JPH10246184A - Load reducing device for air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To open a delivery chamber side to the atmosphere, so that no-load operation can be easily performed and durability, reliability, etc., can be improved, without using a check valve or the like. SOLUTION: In a cylinder head 13 provided in a high pressure side cylinder 10, a first/second delivery chamber D, E is formed, one delivery chamber D is connected to an air tank 19 through an air pipe 20, also the other delivery chamber E is connected to an inflow port 23B of a release valve 21 through an unloading flow pipe 22. In a valve plate 14 in a side of the cylinder head 13, delivery valves 16, 17 are provided, which connect/interrupt the delivery chambers D, E individually relating to a compression chamber B. A side of a pilot pressure chamber 24 of the release valve 21 is connected to the air tank 19 through a solenoid valve 33 and a pipe 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing the load of an air compressor which is preferably used for supplying compressed air to a pneumatic device such as an air motor or an air cylinder.
In particular, the present invention relates to a load reduction device for an air compressor that can perform a no-load operation when the pressure of compressed air increases significantly.

[0002]

2. Description of the Related Art Generally, a compression chamber is defined between a crankcase in which a crankshaft is rotatably provided, a cylinder mounted on the crankcase, and a piston in the cylinder provided on the cylinder. A cylinder head, a suction chamber and a discharge chamber provided independently of each other in the cylinder head, an electric motor provided in the crankcase as a drive source for rotating the crankshaft, and provided on the suction chamber side. The reciprocating air compressor includes an unloading mechanism that allows the suction valve to open and close in accordance with the reciprocating motion of the piston at all times, and holds the suction valve in an open state during no-load operation. For example, JP-A-8-6123
No. 5 publication.

In this type of prior art air compressor,
By rotating the crankshaft by the electric motor to reciprocate the piston in the cylinder, the air sucked from the suction chamber side is compressed in the compression chamber, and the compressed air is discharged from the discharge chamber to an external air tank or the like. A so-called compression operation is performed.

When the pressure in the air tank rises to a predetermined maximum set pressure by the compression operation, the unloading mechanism is operated to forcibly open the suction valve, and the compression chamber is closed by the suction valve and the suction valve. By communicating with the atmosphere via the suction chamber, the no-load operation is performed while the rotation of the electric motor is continued.

[0005] The unloading mechanism includes an electromagnetic actuator provided on the cylinder head located on the suction chamber side, an unloading piston driven by the electromagnetic actuator to push the suction valve, and the like. During normal compression operation, the unload piston is separated from the suction valve to allow the suction valve to open and close according to the reciprocating motion of the piston.

[0006] When the pressure in the air tank rises to the highest set pressure by the compression operation, the unload piston drives the unload piston toward the suction valve side by the electromagnetic actuator, so that the unload piston operates the suction valve. Push to forcibly open the valve and start unload operation as no-load operation.

As a result, while the suction valve is kept open, the pressure in the compression chamber is maintained at the atmospheric pressure even if the reciprocation of the piston is continued by the electric motor, and the load applied to the electric motor is reduced. It is possible to perform no-load operation with reduced load.

[0008] This eliminates the need to start and stop the electric motor in response to pressure fluctuations in the air tank, thereby saving power. When starting the electric motor to start the compression operation,
Until this motor reaches the rated rotation, the suction valve is opened for a predetermined time by the unload mechanism so that the starting load can be reduced.

[0009]

In the above-mentioned prior art, the unload piston is driven by the electromagnetic actuator during the no-load operation, and at this time, the suction valve is pushed by the unload piston to operate the suction valve. Since the valve is forcibly opened, the following problems occur.

That is, in the prior art, when the unloading mechanism is operated during the compression operation in which the suction valve is opened and closed with the reciprocation of the piston, for example, the unloading mechanism driven by the electromagnetic actuator is operated. The load piston strongly collides with the suction valve during the opening and closing operations, and the shock at this time may cause the suction valve to be worn and damaged early.

When the piston in the cylinder is in the discharge (compression) stroke, the suction valve is closed,
Since the compression chamber in the cylinder is pressurized to a high pressure state with the compressed air, when the unload mechanism is operated at the moment of the discharge stroke, the suction valve is forcibly opened by the unload piston against the high pressure in the compression chamber. Therefore, it is necessary to apply a large driving force to the unload piston by the electromagnetic actuator. In particular, in the case of a large compressor that generates high-pressure compressed air, the electromagnetic actuator and the like must be increased in size in order to increase the driving force of the unload piston by the electromagnetic actuator.

On the other hand, in a multistage air compressor in which a plurality of cylinders (cylinders) are provided in a crankcase of a compressor body, a suction valve for each cylinder is forcibly operated by a respective unload mechanism during an unload operation. A configuration in which a valve is opened is known. However, in this case, since an unloading mechanism is provided for each cylinder, the number of parts increases, the workability at the time of assembly decreases, and the control circuit of each unloading mechanism becomes complicated. However, there is a problem that the manufacturing cost is increased.

Further, as another prior art, for example, a check valve is provided between an air tank and a discharge chamber of a cylinder head to prevent compressed air in the air tank from flowing back to the discharge chamber side, There is also known a configuration in which an unload mechanism for opening the discharge chamber to the atmosphere is provided on the discharge chamber side of the head.

However, in this case, during a normal compression operation, high-pressure compressed air is discharged from the discharge chamber side to the air tank via the check valve, so that the check valve of the high-temperature compressed air is discharged. It is always exposed to thermal influences, and tends to thermally deteriorate early. In order to prevent this, it is necessary to use a high-quality check valve that can withstand high temperatures, high pressures, or high loads. This not only increases the cost but also increases the quality of the check valve. There is a problem that it is difficult to always secure operation stability (reliability) as a valve for a long period of time.

The present invention has been made in view of the above-described problems of the prior art, and the present invention can easily perform a no-load operation by opening the discharge chamber side to the atmosphere without using a check valve or the like. It is another object of the present invention to provide a load reducing device for an air compressor which can improve durability, reliability, and the like.

Another object of the present invention is to reduce the number of parts by eliminating the need to provide an unloading mechanism for each cylinder, even when applied to, for example, a multi-stage air compressor. An object of the present invention is to provide a load reducing device for an air compressor which can improve workability at the time of assembling, simplify the entire structure, and extend durability and life.

[0017]

In order to solve the above-mentioned problems, the present invention has at least a compression chamber and first and second discharge chambers. A compressor body provided with first and second discharge valves that are opened and closed independently of each other between a second discharge chamber and a compression chamber; and a compressor body provided in the compressor body and the compression chamber. And a drive source for driving the compressor body to generate compressed air, and connected to one of the discharge chambers of the compressor body and discharged from the compression chamber via one of the discharge chambers. An air tank for storing compressed air and the other discharge chamber of the compressor main body are connected to each other, and the other discharge chamber is kept in a high-pressure state by closing the valve at all times. Valve means for opening the discharge chamber to the atmosphere, and opening and closing of the valve means by an external signal Adopts a configuration comprising a that the valve drive means.

According to the above construction, one of the first and second discharge chambers provided in the compressor body is connected to the air tank, and the other discharge chamber is connected to the valve means. When the valve means is opened by the valve driving means during the no-load operation, the other discharge chamber can be opened to the atmosphere, and the pressure of the compressor body and the driving source is reduced by reducing the pressure in the compression chamber to the atmospheric pressure state. Can be reduced automatically. Since the pressure from the air tank acts on the discharge valve on the one discharge chamber side, the discharge valve can be maintained in a high pressure state by maintaining the closed state of the discharge valve, and stored in the air tank. It is possible to prevent the compressed air leaked to the outside during the no-load operation.

[0019]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 to 4 show an example in which the load reducing device for an air compressor according to the embodiment of the present invention is applied to a reciprocating two-stage air compressor.

In FIG. 1, reference numeral 1 denotes a compressor main body constituting a main body of the compressor. The compressor main body 1 is a horizontally opposed two-stage compressor comprising a crankcase 2 and cylinders 5 and 10 to be described later. It is configured. A crankshaft 3 is rotatably provided in a crankcase 2 of the compressor body 1, and the crankshaft 3 is driven to rotate by an electric motor 18 described later. A cooling fan 4 is provided at a tip end of a crankshaft 3 protruding from the crankcase 2 to the outside.
It is configured to generate cooling wind toward zero or the like.

Reference numeral 5 denotes a low-pressure cylinder constituting a first cylinder provided in the crankcase 2, reference numeral 6 denotes a piston slidably inserted into the low-pressure cylinder 5, and the piston 6 is a crankshaft. 3, and reciprocates in the low-pressure side cylinder 5 as the crankshaft 3 is driven to rotate by the electric motor 18. A low-pressure side compression chamber A is defined in the low-pressure side cylinder 5 between the piston 6 and a cylinder head 8 described later.

A cylinder head 8 is provided at the tip end of the low-pressure cylinder 5 and constitutes a first cylinder together with the low-pressure cylinder 5. Communicating via suction valve and discharge valve,
A suction chamber and a discharge chamber (both not shown) that are shut off are formed. The suction chamber of the cylinder head 8 communicates with the outside air through a suction silencer (not shown) or the like, and when the suction valve is opened, external air is supplied to the compression chamber A of the low-pressure side cylinder 5.
It is designed to be sucked inside. A discharge port 8A is provided on the discharge chamber side of the cylinder head 8.
A is connected via a communication pipe 9 to a suction chamber C on the high-pressure side described later.

A high-pressure cylinder 10 is located on the opposite side of the low-pressure cylinder 5 and constitutes a second cylinder provided in the crankcase 2. The high-pressure cylinder 10 has a smaller cylinder diameter than the low-pressure cylinder 5. And generate high-pressure compressed air. Reference numeral 11 denotes a piston slidably inserted into the high-pressure side cylinder 10. The piston 11 is connected to the crankshaft 3 via a connecting rod 12, and rotates inside the high-pressure side cylinder 10 with rotation of the crankshaft 3. Reciprocate.

A cylinder head 13 is provided at the tip end of the high pressure side cylinder 10 and constitutes a second cylinder together with the high pressure side cylinder 10. The cylinder head 13 is inserted into the high pressure side cylinder 10 with the piston 11. A compression chamber B is formed. A valve plate 14 is provided between the cylinder head 13 and the high-pressure side cylinder 10, and the valve plate 14 is provided in the cylinder head 13 as shown in FIG.
Second discharge chambers D and E are defined.

One of the discharge chambers D and E is connected to an air tank 19 described later via an air pipe 20, and the other discharge chamber E is connected to a release valve 21 described later for unloading. Are connected via a conduit 22. Further, the compression chamber B of the high-pressure side cylinder 10 is provided in the valve plate 14.
A suction valve 15 for communicating and shutting off the inside of the suction chamber C is provided, and first and second discharge valves 16 and 17 for connecting and shutting off the compression chamber B to discharge chambers D and E are provided.

Here, the discharge valves 16 and 17 are composed of reed valves and the like, and are configured to open and close the discharge chambers D and E independently of the inside of the compression chamber B. The cylinder head 13 is provided with a suction port 13A that is always in communication with the suction chamber C. The suction port 13A is connected to the low-pressure side discharge port 8A via the communication pipe 9.

Reference numeral 18 denotes an electric motor as a drive source provided integrally with the crankcase 2 of the compressor body 1. A motor case 18A of the electric motor 18 forms a part of the crankcase 2 as shown in FIG. So as to be integrally provided on one side of the crankcase 2. The rotating shaft 18B of the electric motor 18 is integrally connected to the crankshaft 3 in the crankcase 2 to rotate the crankshaft 3.

Reference numeral 19 denotes an air tank for storing compressed air.
The air tank 19 is formed as a substantially cylindrical airtight container as shown in FIG. 2. For example, a connection pipe portion 19 </ b> A for introducing compressed air into and out of the air tank 19 is integrated with an upper side of the air tank 19. It is provided in. The air tank 19 is connected to a discharge chamber D formed in the cylinder head 13 on the high-pressure side via an air pipe 20, and the high-pressure compressed air generated in the compression chamber B of the high-pressure cylinder 10 is discharged from the discharge chamber D Is stored in the air tank 19 through the air pipe 20.

A release valve 21 is connected to a discharge chamber E of the cylinder head 13 via a conduit 22 for unloading. The release valve 21 is a piston slide as shown in FIGS. The valve housing 23 has a hole 23A formed as an axial stepped hole, an inflow port 23B and a pilot port 23C spaced apart in the axial direction of the piston sliding hole 23A, and one end of the piston sliding hole 23A. A plug 25 which is screwed to one end of the valve housing 23 so as to close the side thereof and defines a pilot pressure chamber 24 which is always in communication with a pilot port 23C between the valve housing 23 and a stepped piston 29 which will be described later; And a body 30 and the like.

Here, on the other end side of the valve housing 23,
Annular valve seat 2 between the other end surface of piston sliding hole 23A
An enlarged hole 23E forming 3D is provided.
3E is a cover cylinder 26 which forms a part of the valve housing 23.
Covered by The cover cylinder 26 defines an atmosphere opening chamber 27 between the cover cylinder 26 and the enlarged diameter hole 23E, and the atmosphere opening chamber 27 is provided with a silencing filter 2 made of a porous sintered metal or the like.
8 so as to always communicate with the outside air.

Reference numeral 29 denotes a stepped piston inserted into a piston sliding hole 23A of the valve housing 23. The stepped piston 29 has a small-diameter shaft portion 29A extending coaxially toward the enlarged-diameter hole 23E. A valve body 30 formed in a short cylindrical shape is integrally fixed to a distal end side of the small diameter shaft portion 29A via a nut 31. An annular valve seat 32 is provided on one end side of the valve body 30, and the valve seat 32 is detachably seated on the annular valve seat 23 </ b> D of the valve housing 23 together with the valve body 30.

Here, the stepped piston 29 receives the pressure from the inflow port 23B on the end face 29B side, so that while the pilot pressure chamber 24 side is in the atmospheric pressure state, FIG.
It is pressed in the direction of arrow F in the middle. Thus, the stepped piston 29 moves the valve body 30 to the annular valve seat 23D and the valve seat 3
2 and the inflow port 23B is connected to the atmosphere opening chamber 2
7 shut off.

On the other hand, when high-pressure compressed air is supplied into the pilot pressure chamber 24 via a pipe 35 described later, the stepped piston 29 receives this pressure on the end face 29C side. Further, since the stepped piston 29 has a larger pressure receiving area on the end face 29C side than on the end face 29B side, even if the pressure state between the inflow port 23B and the pilot port 23C is almost equal, the stepped piston 29 is stepped. The piston 29 is pressed in the direction of arrow G by the pressure receiving area difference between the end faces 29B and 29C.

As a result, when the valve body 30 is separated from the annular valve seat 23D of the valve housing 23 together with the valve seat 32, the valve body 30 is opened and the inflow port 23B communicates with the atmosphere opening chamber 27. The compressed air flowing from the inflow port 23 </ b> B to the open-to-atmosphere chamber 27 is discharged to the outside via the silencing filter 28. Thereby, the discharge chamber E of the cylinder head 13 shown in FIG. 2 is opened to the atmosphere by the release valve 21 through the unloading conduit 22 and the high-pressure side cylinder 10 communicated with the discharge chamber E through the discharge valve 17. The pressure in the inner compression chamber B automatically decreases to a state close to the atmospheric pressure by opening the release valve 21.

At this time, the silencing filter 28 reduces the exhaust noise of the compressed air discharged from the open-to-atmosphere chamber 27 to the outside of the cover cylinder 26, thereby suppressing the generation of noise. This prevents entry into the open chamber 27 and suppresses early wear and damage of the sliding surfaces of the valve seat 32 and the stepped piston 29 by dust.

Further, the silencing filter 28 has a porous structure so as to give a throttle resistance to the compressed air discharged from the open-to-air chamber 27 to the outside, and to provide a constant pressure lower than the atmospheric pressure to the open-to-air chamber 27 side. Only a slightly higher pressure is created.
Thus, for example, when switching from the no-load operation (unload operation) to the compression operation, if the pilot pressure chamber 24 is set to the atmospheric pressure state, the air release chamber 27 is set to at least a pressure higher than the atmospheric pressure. Therefore, the stepped piston 29 receives a higher pressure than the end face 29C side of the stepped piston 29, so that the stepped piston 29 is pressed in the direction of arrow F in FIG. At the same time, the release valve 21 is automatically closed by seating on the annular valve seat 23D of the valve housing 23.

Reference numeral 33 denotes an electromagnetic valve as valve driving means for opening and closing the release valve 21. The electromagnetic valve 33 has an inlet 33A, an outlet 33B and an outlet 33C.
Directional solenoid valve and the like.
4 is connected to the connection pipe 19A of the air tank 19. The electromagnetic valve 33 has an outflow port 33B serving as an atmosphere opening port, and an outflow port 33C connected to a pilot port 23C of the release valve 21 via a pipe 35.

Here, the solenoid valve 33 is connected to a control device 36 described later.
, The outlet 33C is normally communicated with the outlet 33B, and the inlet 33A is shut off from the outlet 33B and the outlet 33C. At this time, the pilot port 23C of the release valve 21 is connected to the pipe 35 and the outlet 33C and the outlet 33C of the solenoid valve 33.
B is released to the atmosphere through B, so that the release valve 21
The pilot pressure chamber 24 is brought into an atmospheric pressure state as shown in FIG. 3, and the stepped piston 29 connects the valve 30 to the inflow port 23B.
The valve is kept closed by the side pressure.

When the solenoid valve 33 is switched by a control signal from the control device 36, the inlet 33A of the solenoid valve 33 communicates with the outlet 33C, and the outlet 33B connects to the inlet 33A and the outlet 33C. Will be shut off. Thereby, the compressed air in the air tank 19 is
4. The pilot pressure chamber 24 of the release valve 21 is supplied to the pilot pressure chamber 24 through the inflow port 33A, the outflow port 33C, and the pipe 35 of the solenoid valve 33. The stepped piston 29 of the release valve 21 is pressed in the direction of the arrow G as shown in FIG. 4 to forcibly open the valve body 30 against the pressure on the inflow port 23B side.

Further, reference numeral 36 denotes a control device for controlling the switching of the solenoid valve 33. The control device 36 has an input side connected to a power supply line of the electric motor 18 as a voltage detector and an output side connected to the solenoid valve 33. Have been. Here, the electric motor 18 is connected to a commercial power supply (not shown) or the like via an outlet 37 at the end of the power supply line, and the voltage supplied from the power supply to the electric motor 18 varies depending on the load state of the electric motor 18. It is known to vary in response.

Therefore, the controller 36 controls the electric motor 1
The voltage value supplied from the power supply to the power supply 8 is detected by the voltage detector, and thereby the load state of the electric motor 18 is monitored. When the voltage value is at the normal voltage level, it can be determined that the electric motor 18 is in the normal compression operation state. Therefore, the control device 36 excites the solenoid valve 33 by a control signal, 33C is communicated with the outlet 33B, and the inlet 33A is blocked from the outlet 33B and the outlet 33C.

On the other hand, when the pressure of the compressed air generated in the high-pressure side cylinder 10 becomes higher than the set pressure on the air tank 19 side, the compression chambers A and B of the compressor body 1 (see FIG. 1) are relatively high. It becomes pressure state, and high pressure
1, the rotational load on the crankshaft 3 increases, and the electric motor 18 receives a large rotational load. In this case, the voltage value is
8, the control device 36 demagnetizes the solenoid valve 33 to control the switching of the solenoid valve 33, and connects the inflow port 33A of the solenoid valve 33 to the outflow port 33C. 33B to the inlet 33A and the outlet 3
Cut off to 3C.

The load reducing device for a two-stage air compressor according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

First, when the crankshaft 3 is driven to rotate by the rotating shaft 18B of the electric motor 18, each of the cylinders 5, 10
Each of the pistons 6 and 11 is reciprocated inside, and a compression operation for generating compressed air in each of the compression chambers A and B is performed. The compressed air generated in the compression chamber A of the low-pressure side cylinder 5 by this compression operation is supplied from the discharge port 8A of the cylinder head 8 to the high-pressure side cylinder 10 through the communication pipe 9.
Is discharged into the suction chamber C.

In the compression chamber B of the high-pressure side cylinder 10, the compressed air is sucked from the suction chamber C in accordance with the reciprocating motion of the piston 11 and is compressed to a higher pressure level, so that the high-pressure compressed air is compressed. Discharge valve 16,1
The ink is discharged to the respective discharge chambers D and E via the nozzle 7.

In this case, since the release valve 21 is kept closed in the normal compression operation state, the unloading conduit 22 is connected to the inflow port 23B of the release valve 21.
The pressure in the discharge chamber E connected through the air tank 1
The pressure rises faster than 9. When the pressure in the discharge chamber E becomes higher than the pressure in the compression chamber B of the high-pressure side cylinder 10, the discharge valve 17 is kept closed even when the piston 11 reciprocates.

On the other hand, on the discharge chamber D side connected to the air tank 19 via the air pipe 20, the discharge valve 16 keeps opening and closing according to the reciprocation of the piston 11, whereby
High-pressure compressed air generated in the compression chamber B of the high-pressure side cylinder 10 is discharged into the discharge chamber D when the discharge valve 16 is opened, and the compressed air is sequentially stored in the air tank 19 via the air pipe 20. Will be.

During the compression operation, the voltage value supplied from the power supply to the electric motor 18 maintains the normal voltage level, so that the control device 36 continues to excite the solenoid valve 33,
The pilot pressure chamber 24 of the release valve 21 is set to the atmospheric pressure state by making the outlet 33C of the solenoid valve 33 communicate with the outlet 33B and closing the inlet 33A with respect to the outlet 33B and the outlet 33C. .

Next, when the pressure in the air tank 19 increases to the set pressure level during the compression operation as described above, the compression chambers A and B of the compressor body 1 (see FIG. 1) Since the pressure is relatively high, the electric motor 18 receives a large rotational load. Then, when the voltage value decreases to a predetermined voltage value according to the load of the electric motor 18, the control device 36 performs switching control of the electromagnetic valve 33 so that the electromagnetic valve 33 is automatically demagnetized.
The solenoid valve 33 connects the inflow port 33A to the outflow port 33C and shuts off the outflow port 33B.

As a result, the compressed air in the air tank 19 is supplied to the pilot pressure chamber 24 of the release valve 21 via the pipe 34, the solenoid valve 33, and the pipe 35. Rise to equal pressure. The stepped piston 29 of the release valve 21 applies pressure from the pilot pressure chamber 24 to the end face 29.
The pressure is received on the side C, and the pressure receiving area on the end face 29C side is larger than that on the end face 29B side by the small diameter shaft portion 29A of the stepped piston 29, so that the stepped piston 29 moves in the direction of arrow G as shown in FIG. When the valve 30 is pressed, the
The valve is forcibly opened against the pressure on the B side.

As a result, the valve body 30 of the release valve 21
Is separated from the annular valve seat 23D of the valve housing 23 together with the valve seat 32, and the inflow port 23B is
The discharge chamber E of the cylinder head 13 shown in FIG. 2 is opened to the atmosphere via the unloading conduit 22 and the like. The pressure in the compression chamber B in the high-pressure cylinder 10 which is communicated with the discharge chamber E via the discharge valve 17 is reduced to the atmospheric pressure state by opening the release valve 21. The pressure in the chamber A also decreases to the atmospheric pressure level, and the compressor body 1 is operated in unload (no load) operation, so that the load on the electric motor 18 can be automatically reduced.

In a case where the electric motor 18 which has been temporarily stopped is restarted in a state where compressed air is stored in the air tank 19 in advance, the electric motor 1
When the starting load acts on the motor 8, the voltage supplied from the power supply to the electric motor 18 may be greatly reduced. In this case as well, the control device 36 controls the solenoid valve 33
, The pressure in the air tank 19 is introduced into the pilot pressure chamber 24 of the release valve 21,
The load at the time of starting is reduced by opening the release valve 21.

Next, in this state, when the voltage value supplied to the electric motor 18 rises to a regular voltage level, the control device 36 excites the solenoid valve 33 so that the inlet of the solenoid valve 33 is opened. 33A, the outlet valve 33C communicates with the outlet port 33B, and the release valve 2
The first pilot pressure chamber 24 is set to the atmospheric pressure state. As a result, the release valve 21 is again closed, and the compressor body 1 is operated for compression by the electric motor 18.

Thus, according to the present embodiment, the first and second discharge chambers D and E are formed in the cylinder head 13 provided in the high-pressure side cylinder 10, and one of the discharge chambers D is connected via the air pipe 20. The discharge valve E is connected to the air tank 19 and the other discharge chamber E is connected to the release valve 2 via a conduit 22 for unloading.
1 and the pilot port 23C (pilot pressure chamber 24) side of the release valve 21 is connected to the air tank 19 via the pipe 35, the solenoid valve 33 and the pipe 34. Various operational effects can be obtained.

That is, the control device 36 for switching and controlling the solenoid valve 33 monitors the load state of the electric motor 18 while
By continuing to excite the electromagnetic valve 33 until the load on the electric motor 18 becomes excessive, the release valve 21 can be maintained in a closed state, the discharge chamber E is maintained in a high pressure state, and the compressor body 1 is moved by the electric motor 18. , And the compression operation can be continued.

By such a compression operation, sufficient compressed air is stored in the air tank 19, and when the pressure in the air tank 19 rises to a level exceeding the set pressure, the load on the electric motor 18 increases. Therefore, the solenoid valve 33 can be demagnetized by a control signal from the control device 36 and the release valve 21 can be forcibly opened by the pressure from the air tank 19.

As a result, the discharge chamber E can be opened to the atmosphere via the unloading conduit 22, so that both the compression chambers B and A of the compressor main body 1 can be reduced in pressure to the atmospheric pressure, and the compressor can be compressed. The unload operation of the main body 1 can be performed, and the load on the electric motor 18 can be automatically reduced.

The first and second discharge chambers D and E formed in the cylinder head 13 are separated from the compression chamber B by the first and second discharge chambers.
The discharge chambers D and E are connected to the respective discharge valves 16 and 17 individually.
17, the compression chamber B can be opened and closed independently. For example, even when the discharge chamber E side is opened to the atmosphere via the release valve 21 for performing no-load operation, the compression in the air tank 19 is prevented. The discharge valve 16 can prevent air from flowing backward from the discharge chamber D to the compression chamber B side.

Therefore, according to the present embodiment, two discharge chambers D and E are formed in the cylinder head 13 and the discharge chambers D and E are formed.
E is independently opened and closed with respect to the compression chamber B by the respective discharge valves 16 and 17, so that, for example, a check valve is provided in the middle of the air pipe 20 connecting one discharge chamber D to the air tank 19. Air tank 1 without providing
When the pressure in the interior 9 becomes sufficiently high, the other discharge chamber E side is opened to the atmosphere via the release valve 21 so that no-load operation can be easily performed, and the load applied to the electric motor 18 is automatically reduced. Can be reduced.

The discharge valves 16, 17 provided between the compression chamber B and the discharge chambers D, E are constituted by reed valves and the like which open and close on the valve plate 14, so that the discharge valves 16, 17 are provided. Etc. can be prevented from being thermally degraded early even when exposed to high temperature and high pressure compressed air, and the durability and life of the compressor can be reliably improved. By switching to the no-load operation, the operation as the compressor can be stabilized and the reliability can be improved.

Further, by connecting the discharge chamber E formed in the cylinder head 13 on the high pressure side to the release valve 21 via the unloading conduit 22, the compression chambers B and B on the high pressure side and the low pressure side during no load operation. A can reduce the load on the electric motor 18 by lowering the pressure to the atmospheric pressure level, so that it is not necessary to provide an unloading mechanism or the like for each cylinder as in the conventional multi-stage air compressor. The number of parts can be reduced, and workability during assembly can be improved.

Further, the release valve 21 serving as an unloading mechanism is connected to the valve housing 23 and the stepped piston 29.
And the valve body 30 and the like, and the valve body 30 is forcibly opened by using the air pressure from the air tank 19, so that the suction valve is provided by using a push rod or the like as in a conventional unloading mechanism. For example, even if the pressure of the compressed air is increased, it is possible to cope without increasing the size of the release valve 21 and the like, thereby simplifying the entire structure and extending the durability and life. Can be.

In each of the above embodiments, a two-stage air compressor including the low-pressure side cylinder 5 and the high-pressure side cylinder 10 has been described as an example. However, the present invention is not limited to this. The present invention may be applied to a single-stage air compressor having the above-described cylinders, or may be applied to a three-stage or more air compressor. Further, the present invention is not limited to a reciprocating air compressor, and may be applied to, for example, a locking piston type, a rotary type or a scroll type air compressor.

[0065]

According to the present invention, as described in detail above, the first and second discharge chambers and the compression chamber are provided in the compressor body, and these discharge chambers are provided in the compression chamber. On the other hand, the first and second discharge valves are opened and closed independently of each other, and one of these discharge chambers is connected to an air tank, and the other discharge chamber is connected to valve means. With the configuration, during the no-load operation, the other discharge chamber can be opened to the atmosphere by opening the valve means by the valve driving means to reduce the pressure in the compression chamber to the atmospheric pressure state. The load on the main body and the drive source can be automatically reduced. Then, on the one discharge chamber side, the pressure from the air tank acts on the discharge valve, so that the discharge valve can be kept in a closed state, and the compressed air stored in the air tank is operated during no-load operation. Leakage to the outside can be reliably prevented.

Therefore, without using a check valve or the like,
For example, by exposing the second discharge chamber side to the atmosphere, no-load operation can be easily performed, and durability and reliability can be improved. Also, for example, even when applied to a multi-stage air compressor, there is no need to provide an unloading mechanism for each cylinder, so that the number of parts can be reduced, workability during assembly can be improved, and the overall structure can be simplified. And the durability and life can be extended.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a two-stage air compressor according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a load reduction device showing a high pressure side cylinder and a cylinder head in FIG. 1 together with a release valve and the like.

FIG. 3 is an enlarged longitudinal sectional view showing a release valve in FIG. 2;

FIG. 4 is a longitudinal sectional view similar to FIG. 3, showing a state when a release valve is opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor main body 2 Crankcase 3 Crankshaft 5 Low pressure side cylinder 6, 11 Piston 8, 13 Cylinder head 9 Communication pipe 10 High pressure side cylinder 15 Suction valve 16 First discharge valve 17 Second discharge valve 18 Electric motor (drive Source) 19 Air tank 21 Release valve (Valve means) 22 Unloading conduit 23 Valve housing 24 Pilot pressure chamber 27 Atmospheric release chamber 28 Silence filter 29 Stepped piston 30 Valve body 33 Solenoid valve (Valve driving means) A, B Compression chamber C Suction chamber D First discharge chamber E Second discharge chamber

Claims (1)

[Claims] The first and second discharge chambers have at least a compression chamber and first and second discharge chambers, and the first and second discharge chambers and the compression chamber are opened and closed independently of each other. A compressor main body provided with a second discharge valve; a drive source provided in the compressor main body for driving the compressor main body to generate compressed air in the compression chamber; An air tank connected to one of the discharge chambers for storing compressed air discharged from the compression chamber through one of the discharge chambers, and connected to the other discharge chamber of the compressor body, By closing the valve, the other discharge chamber is maintained at a high pressure state, and when no load operation is performed, the valve is opened to open the other discharge chamber to the atmosphere, and the valve is opened and closed by an external signal. And a valve driving means for the air compressor.