JPH1162847A - Load decreasing mechanism of multiple stage compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid interruption of the operation of a multiple stage compressor by avoiding the stop of the multiple stage compressor caused by overload of a driving motor, to be generated caused by large torque to be generated in starting of the multiple stage compressor or in using a plurality of power tools. SOLUTION: A communication pipe passage 23 is provided between a discharge port 22 of a cylinder 9 on the first stage side (low pressure) of a multiple stage compressor 1 and a suction port 22' on the second stage side (high pressure), discharge valves capable of being freely opened and closed are provided on heads of respective cylinders, stable compressed air from an air tank 2 in relation to the discharge valves is allowed to flow through a communication pipe passage 17, a solenoid valve 19 is interposed, the solenoid valve 19 opens respective discharging valves in detecting of overload so as to communicate with the atmosphere, and therefore, over-compression can be avoided, the stop of the driving motor can be avoided, and the multiple stage compressor can be continuously operated. Accordingly, since the solenoid valve is operated by approximately constant pressure in the air tank, the stable operation can be performed, the discharge valves can communicate with the atmosphere, and overload of the multiple stage compressors can be reliably decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The disclosed technology relates to a mechanism for reducing the load so that the operation of the compressor is not stopped when the multi-stage compressor is started and when the load on the drive motor during operation becomes greater than a specified value. Belongs to the technical field.

[0002]

2. Description of the Related Art As is well known, a compressor is widely used in many construction fields or facilities, but a high compression ratio torque is required depending on the application, and the compressor is provided integrally with the compressor. When storing compressed air at a predetermined pressure in an air tank, a multi-stage compressor that uses two or three-stage cylinders rather than a single-stage cylinder to increase the compression efficiency is used. It has become to.

In particular, small- and medium-sized compressors equipped with a two-stage cylinder have been frequently used recently in various construction sites, etc. from the viewpoint of ease of use.

A driving motor for operating a piston set in each cylinder of such a multi-stage compressor via a connecting rod requires a large torque at the time of starting the motor, resulting in an overload, and in a construction work or the like. In use, for example, when using another electric tool from the same power supply via a cord reel, in order to use the compressor together with this kind of electric tool at the same time at once, the voltage decreases, If the drive is continued to be used in this state, the drive motor is also overloaded, and there is a risk that the drive motor may be damaged, such as burn-in, so a thermal protector for preventing motor burnout is provided to deal with this. The thermal protector operates to cut off power supply and stop the compressor to prevent compressor trouble due to overtorque. It is sea urchin.

However, in such a mode of using the thermal protector for preventing motor burnout, there is a problem that the compressor is temporarily stopped due to the stop of the power supply to the motor, and the actuator cannot be continuously used by the compressed air.

To cope with this, for example, Japanese Patent Laid-Open No. 9-7 / 1990
As shown in the invention of No. 9145, for example, in a two-stage compressor, a communication pipe passage is provided between a discharge port on the first stage (low pressure) and an intake port on the second stage (high pressure), An electromagnetic valve is interposed in the middle of the communication pipe passage to detect the current value of the drive motor or the terminal voltage value, and when the current value or the terminal voltage value exceeds the set value, the electromagnetic valve A technology has been developed in which the pressure on the intake side of the two-stage side (high pressure) is reduced by opening the opening.

[0007]

However, compared to the air pressure stored in the air tank, the fluctuations in the operating one-stage (low pressure) and the second-stage (high pressure) pressures are large. The solenoid valve interposed in the connecting pipe passage merely performs on / off operation, but during the operation, the solenoid valve is reliably turned on / off by the fluctuating pressure on the one-stage side (low pressure) and the two-stage side (high pressure). In order to perform this operation, the operating voltage of the solenoid valve must be adjusted according to the fluctuating pressure so that the valve operates normally, and the adjusting mechanism becomes complicated. However, it cannot operate normally, and there is a problem that pressure leak occurs and overload prevention of the compressor cannot be completely protected.In addition, there is a drawback that the structure must be complicated in terms of design. Costs are high, Management operation at the time there was a inconvenience to cumbersome maintenance becomes complicated.

[0008]

SUMMARY OF THE INVENTION The object of the invention of this application is to solve the problems of the overload preventing and adjusting mechanism of a multi-stage compressor or the like based on the above-mentioned prior art, and has a first stage (low pressure) and a second stage (high pressure). ) Of the air tank which has less pressure fluctuation than the pressure fluctuation in the communication pipe passage while taking advantage of the advantage of preventing overload by adjusting the pressure by operating the solenoid valve interposed between the discharge port and the intake port of the cylinder head. By using the stored pressure, the pressure of the discharge port on the first stage (low pressure) and the pressure of the intake port on the second stage (high pressure) communicate with the atmosphere, so that the pressure of the multi-stage cylinder does not increase, and the load is reduced. An object of the present invention is to provide an excellent load reduction mechanism for a multi-stage compressor that avoids stoppage of a drive motor and allows the compressor to continue operating, thereby benefiting air compression technology applications in various construction industries.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a configuration of the invention of the present application for solving the above-mentioned problems is provided in a multi-stage compressor provided with a multi-stage cylinder. A communication pipe is provided between the intake port of the cylinder and the discharge port of the low-pressure cylinder, and an electromagnetic valve provided in conjunction with a load detection mechanism electrically connected to a drive motor is provided at an intermediate portion of the communication pipe, The discharge valve linked to the solenoid valve is made to face the intake port and the discharge port of the head of each cylinder, and the communication pipe is connected to the air tank so that it is passed over the back of the cooling fan installed on the air tank. Technical measures taken.

[0010]

When the multi-stage compressor is driven, or when the plurality of electric tools are used simultaneously at the same time via the cord reel from the same power source, these electric tools are used simultaneously at the same time. When the drive motor of the compressor is overloaded and the torque of the drive motor becomes large, when the torque over exceeds the set value as the motor current value or the terminal voltage value, The load detection mechanism electrically connected to the drive motor operates to operate the solenoid valve interposed in the communication pipe, and the solenoid valve is operated by the pressure that the air tank pressure fluctuates only slightly. The electromagnetic valve always operates stably, and the compressed air in the air tank is provided alongside the electromagnetic valve via the electromagnetic valve, and is provided at the head of each cylinder on the first stage (low pressure) and the second stage (high pressure). Release bar Open the compressor and release the air in the compression process to the atmosphere, the pressure in the multi-stage cylinder does not rise, the load is reduced, the stop of the drive motor is prevented, and the compressor can be operated continuously, reducing the load The loss of time is reduced, and therefore, the set value of the current value or the terminal voltage value of the load detection mechanism can be reduced. Therefore, the communication pipe passage is connected to the first stage (low pressure) cylinder head from the head. Provided on the back of the cooling fan mounted on the device frame while being passed between the head of the stage (high pressure) cylinder and discharging and sucking air from the first stage (low pressure) to the second stage (high pressure) Since the cooling efficiency can be improved in the process and the compression efficiency can be improved, efficient operation is possible.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

In the illustrated embodiment, reference numeral 1 denotes a multi-stage compressor which is the center of the gist of the invention of the present application, and shows a two-stage compressor as an embodiment, and a pair of air tanks 2 and 2 forming a base thereof have a base. Each of the air tanks 2 and 2 forms a base frame having blocks 3 and 3 and can be stably set. A drive motor 5 has a field coil 6 and a rotor 7 and is disposed at a substantially central position. A crankcase 8 has a left-right one-stage (low-pressure) cylinder 9 and a two-stage (high-pressure) cylinder 9. Are provided symmetrically and have compression pistons 12 and 13 therein.

A load detector block 14 is provided below the frame base 4 near one side.

As shown in FIG. 5, the load detecting device block 14 is provided with a predetermined load detecting mechanism 18 connected to the drive motor 5 via a cable (not shown). It is electrically connected to an interposed electromagnetic valve 19.

A pipe passage 24 branched from the pipe passage 17 is connected to the discharge port 2 of the cylinder 9 on the first stage (low pressure).
5 and the discharge port 25 'of the second stage (high pressure) cylinder 10
The discharge valves 26, 26 'provided on the heads of the respective cylinders 9, 10 are openable and closable, and the discharge valve main body 27 is always in a closed position via a return spring 28.

When the valve body 27 is led out through the solenoid valve 19 by the compressed air stably stored from the air tank 2, the valve body 27 is opposed to the return spring 28 as shown in FIGS. As shown in FIG. 5, the intake port 28 '' and the discharge port 28 '''' are opened so that air is discharged through the discharge flapper valve 21 to the outside air through the discharge ports 25 and 25 'so that compressed air is not formed. The first-stage (low-pressure) cylinder 9 is of a downward intake type as in the conventional mode, and is provided with an intake flap valve 20 and a discharge flapper valve 21.
A communication pipe passage 23 is provided between the discharge port 22 and an intake port 22 ′ of the second-stage (high-pressure) cylinder 10.

In the second stage (high pressure) cylinder 10, reference numeral 21 'denotes a discharge flapper valve.

As shown in FIGS. 1 to 3, the communication pipe passage 23 has a discharge port 22 of the first-stage (low-pressure) cylinder 9 and a second-stage (high-pressure) cylinder 1 at the back of the cooling fan 11.
The first-stage (low-pressure) cylinder 9 is cooled by the cooling fan 11 and connected to the second-stage (high-pressure) cylinder 9 to be cooled and sent and sucked. The compression efficiency of the second-stage (high-pressure) cylinder 10 is improved.

In FIG. 6A, reference numeral 28 "denotes an intake port of the second-stage (high-pressure) cylinder 9, and 28""in FIG. A discharge port, and 30 in FIGS. 1 and 2 is an instrumentation device block.

In the illustrated embodiment, the air tanks 2 and 2 are symmetrical and have the same shape and have good mass productivity, good form, and low cost. Is designed so that the air tanks 2 and 2 can be mounted symmetrically by changing the position by 180 °.

In FIGS. 6A and 6B, 31 '
Is a discharge port.

It should be noted that the accessory instrumentation unit or the block can be attached via a socket hole which is previously symmetrically blocked and attached via a socket. is there.

In this embodiment, a two-stage cylinder is shown, but the invention of this application is not limited to a two-stage cylinder, but is equipped with a multi-stage cylinder having three or more stages. Things can be targeted.

In the above-described configuration, when the compressor is started, or when a plurality of electric tools are supplied with power through the cord reel of the same electric tool at a construction site or the like, the drive motor 5 of the compressor 1 is overloaded. When the overload is detected by the load detection device block 14 and the current value or the terminal voltage exceeds the set value, the load detection mechanism 18 is activated, the solenoid valve 19 is activated, and the compressed air from the air tank 2 is released. The discharge port 25 of the first-stage (low-pressure) cylinder 9 and the discharge valve 2 of the second-stage (high-pressure) cylinder 10 via the communication pipe passage 17 and the branch pipe passage 24.
7, the discharge port 28 'is opened against the spring 28, and communicates with the atmosphere via the discharge port 31' to communicate with the outside air so that the heads of the cylinders 9 and 10 are not compressed.

In the invention of this application, the solenoid valve 19
Is provided in the communication pipe passage 17 from the air tank 2, the pressure acting on the solenoid valve 19 is substantially constant,
Therefore, there is no pressure fluctuation as in the conventional mode described above, and the solenoid valve 19 can stably maintain the on / off function at all times in the initial set state.

Therefore, an increase in the torque of the compressor 1 is avoided, an overload of the drive motor 5 is prevented, a power supply stop is prevented, and the compressor 1 can be operated continuously including a start-up operation, and the load is steady. In this state, the overload detecting device block 14 is activated, the load detecting mechanism 18 turns off the solenoid valve 19, and the compressed air from the air tank 2 is released from the heads of the cylinders 9, 10 to the valves 26, 26 '. The valve body 27 is returned to the discharge port 28 ″ by the spring 28.
28 '''is closed, and the one-stage and two-stage compressions are continued to perform a predetermined function.

At this time, the communication pipe passage 23 provided between the heads of the cylinders 9 and 10 is connected to the cooling fan 1.
1, the compressed air supplied from the first-stage (low-pressure) cylinder 9 to the second-stage (high-pressure) cylinder 10 is cooled and cooled to the second-stage (high-pressure) cylinder 10.
Can significantly improve the compression efficiency.

The embodiment of the invention of this application is not limited to the above-described embodiment. For example, the cylinder is not limited to a two-stage type, and a plurality of cylinders are radially installed around a crankcase. Various modes can be adopted.

[0029]

As described above, according to the invention of this application, a compressor is basically used in a multi-stage compressor at the time of start-up or operation when a plurality of other power tools are used from the same power supply via a cord reel. There is no danger that the load of the drive motor will be overloaded and the power supply to the drive motor due to the operation of the normally equipped thermal protector will stop and the compressor will stop, and the current value and terminal voltage value of the drive motor will be set. When the pressure rises above the value, the load detection mechanism operates to operate the solenoid valve interposed in the communication passage from the air tank, and the solenoid valve operates by the pressure from the air tank to operate the intake port of the head of each cylinder. By opening the discharge valve provided at the discharge port and opening the cylinder in communication with the atmosphere, the pressure of the multi-stage cylinder does not increase, the load is reduced, and the drive motor stops. Locked, the compressor maintains a continuous operating state load returns to the steady state, the compression operation of the compressor is exerted an excellent effect that takes place efficiently.

Also, a solenoid valve interposed in a passage communicating from the air tank to the discharge port and the intake port of each cylinder can open and operate the discharge port and the intake port of each cylinder to the atmosphere. Since the on / off operation of the solenoid valve is operated at a substantially stable pressure state, the solenoid valve operates stably in the initial setting state of the solenoid valve, and the operating valve is not damaged at all, and the operating valve is not damaged. Since the discharge valve provided at the discharge port or the intake port of the head of each cylinder at the pressure of can be operated, the excellent effect that the discharge valve is reliably operated and stable load prevention can be achieved. Is played.

Further, since the communication pipe is provided behind the cooling fan provided in the air tank, the compression of the cylinder from the first stage (low pressure) to the second stage (high pressure) during normal operation. Since the air is supplied in a cooled state, the compression efficiency is improved, and an excellent effect that the efficiency of the compressor is improved is exhibited.

[Brief description of the drawings]

FIG. 1 is an overall schematic front view of an embodiment of the invention of the present application.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of a layout of a cylinder and a discharge valve.

FIG. 4 is a side view of the same.

FIG. 5 is a schematic structural diagram of a control mechanism of a discharge valve.

FIG. 6 is a schematic cross-sectional view of a main part of a discharge valve, (A) is a cross-sectional view of a main part of a two-stage (high pressure side), and (B) is a cross-sectional view of a main part of a single step (low-pressure side).

[Explanation of symbols]

 Reference Signs List 9 low-pressure cylinder 10 high-pressure cylinder 22 'intake port 22 discharge port 23 communication pipe 19 solenoid valve 14 overload detection device block 2 air tank 5 drive motor 26, 26' discharge valve 1 multi-stage compressor 11 cooling fan

Claims (2)

[Claims] 1. A load reduction mechanism for a multi-stage compressor in which an electromagnetic valve is disposed between a communication pipe extending between an intake port of a high-pressure cylinder and a discharge port of a low-pressure cylinder of a multi-stage cylinder. A load reduction mechanism for a multi-stage compressor, wherein a discharge valve associated with an electromagnetic valve interposed between the load detection mechanism of a drive motor and an intake port and a discharge port of a head of the cylinder are provided. 2. The load reduction mechanism for a multi-stage compressor according to claim 1, wherein said communication pipe is provided behind a cooling fan provided in an air tank.