JP3113757B2 - air compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air compressor and, more particularly, to an air compressor which generates compressed air by opening and closing an intake valve and an exhaust valve in accordance with a reciprocating motion of a piston.

[0002]

2. Description of the Related Art For example, in a reciprocating air compressor, an intake valve and an exhaust valve are provided in a cylinder head, and compressed air is generated by opening and closing the intake valve and the exhaust valve according to reciprocation of a piston. Is configured. In the intake valve and the exhaust valve, one end of a thin metal plate is fixed to a cylinder head and the other end is a free end, and the free end is bent so that an intake air provided between the cylinder head and the cylinder is provided. Open the valve away from the port and exhaust port.

Therefore, in the intake stroke in which the piston moves downward, the free end of the intake valve is separated from the intake port to open the valve. In the compression / exhaust stroke in which the piston moves upward, the free end of the intake valve moves in the intake port. Is closed to switch to the valve closed state, and the free end of the exhaust valve is separated from the exhaust port to open the valve. When the piston moves downward, the free end of the intake valve is separated from the intake port to switch to the open state, and the free end of the exhaust valve is closed by closing the exhaust port.

Therefore, in the air compressor, when the intake valve and the exhaust valve open and close the intake port and the exhaust port with the reciprocating motion of the piston, an operating noise is generated by contacting the cylinder head, and the air is sucked. At the time of discharge, an intake sound and an exhaust sound were generated due to the air flow, and these sounds were combined to generate noise when compressed air was generated. In order to reduce the noise generated by opening and closing the intake and exhaust valves,
In a conventional air compressor, a silencer is provided on the air suction side, or a soundproof structure is adopted by housing the entire air compressor in a package-type housing.

[0005]

However, even if the entire air compressor is housed in the housing as described above, the housing must be provided with an air inlet and an air outlet, and noise is generated by the air inlet and outlet. It leaked from the air outlet, and it was not possible to make a complete soundproof structure.

In order to reduce noise by active noise control, an expensive arithmetic element capable of performing high-speed processing is required, which causes a problem that the manufacturing cost is significantly increased.

[0007] Therefore, an object of the present invention is to provide an air compressor that has solved the above-mentioned problems.

[0008]

According to the present invention, there is provided an air compressor for generating compressed air by opening and closing an intake valve and an exhaust valve provided on a cylinder head in accordance with a reciprocating motion of a piston. Valve opening / closing detecting means for detecting at least one of the opening and closing operations of the exhaust valve, and detecting at least one of the operating sounds generated along with the opening and closing operation of the intake valve or the exhaust valve for a predetermined time. Operating sound detection means, a speaker provided to generate sound toward the cylinder head, and control means, wherein the control means has a phase with the operation sound detected by the operation sound detection means. A reversing operation sound generating means for generating a reversing operation sound shifted by 180 °; and a sound generation control means for generating the reversing operation sound from the speaker. By generating from over months,
The apparatus is characterized in that at least one of the operation sounds generated by the opening and closing operation of the intake valve or the exhaust valve is silenced.

[0009]

When the operation sound detected by the operation sound detection means detects the operation sound generated by the opening / closing operation of the intake valve or the exhaust valve, the operation sound generation means has a phase of 180 degrees with the operation sound detected by the operation sound detection means. By generating the inverted operation sound deviated by ° and generating the inverted operation sound from the speaker, the operation sound generated due to the opening / closing operation of the intake valve or the exhaust valve can be muted.

[0010]

1 to 3 show an embodiment of an air compressor according to the present invention.

An air compressor 1 called a package type compressor has a compressor body 3, a motor 4,
The tank 5 is stored three-dimensionally and compactly.

A gantry 8 is fixed on a base 6 of the housing 2 via an anti-vibration rubber 7. The motor 4 is fixed on the gantry 8 via a spacer 9, and the tank 5 is fixed on the gantry 8 via a bracket 10.

The compressor body 3 has piston / cylinder mechanisms 3A and 3B on the upper part of the crankcase 11. A silencer 12 is mounted on the intake side of the piston / cylinder mechanism 3A.

A driving pulley 13 provided at a rear portion of the compressor body 3 is rotatably driven via a belt 15 wound around a pulley of the motor 4 during an air compression operation.
The pistons of the cylinder mechanisms 3A and 3B are reciprocated. Accordingly, the air sucked from the silencer 12 is compressed by the piston / cylinder mechanisms 3A and 3B and stored in the tank 5 via the pipe 16. The motor 4 has a rotating shaft 4.
A rotation detection sensor 14 for detecting the number of rotations of a is provided.

The compressor body 3 is fixed on a frame 17 provided on a gantry 8 so as to cover the motor 4 and the tank 5 via a vibration-proof rubber (not shown).

The piston / cylinder mechanisms 3A and 3B are configured as shown in FIG. 2, a crankcase 18 is rotatably supported inside a crankcase 11, and a crank chamber 11a for storing oil for cooling and lubricating the crankshaft 18 is formed at the bottom.
A drive pulley 13 that is driven to rotate by the motor 4 is attached to an end of the crankshaft 18.
The large end of the connecting rod 19 is connected to a.

A piston pin 20 is inserted through a small end provided on the upper end side of the connecting rod 19.
The piston 21 is connected via the. Therefore, the rotational movement of the crankshaft 18 is converted into a reciprocating movement of the piston 21 by the swinging movement of the connecting rod 19.

A cylinder 22 has a cylinder chamber 22a in which a piston 21 slides. A cylinder head base 25 having an intake port 23 and an exhaust port 24 is provided on an upper portion of the cylinder 22, and a cylinder head 26 is fixed to an upper surface of the base 25. Cylinder chamber 22
A compression chamber 27 for compressing air is formed between the upper part of the piston 21 in FIG.

The intake port 23 communicates the intake path 26a of the cylinder head 26 with the compression chamber 27, and the air passing through the silencer 12 reaches the compression chamber 27 via the intake path 26a and the intake port 23. Further, the exhaust port 24 communicates the compression chamber 27 with the exhaust path 26b of the cylinder head 26,
The air compressed in the compression chamber 27 is supplied to the exhaust port 24 and the exhaust path 2
The tank 5 is reached via 6b.

Reference numeral 28 denotes an intake valve for opening and closing the intake port 23, which is attached to the lower surface of the cylinder head base 25. An exhaust valve 29 for opening and closing the exhaust port 24 is attached to the upper surface of the cylinder head base 25. The intake valve 28 and the exhaust valve 29 each have a thin metal plate having one end fixed to the cylinder head base 25 and the other end being a free end.
And open.

Reference numeral 30 denotes an intake valve detection sensor (valve opening / closing detecting means) which detects the opening / closing of the intake valve 28 so that the compression chamber 27
And outputs a detection signal when the intake valve 28 is opened. Reference numeral 31 denotes an intake microphone (operation sound detection means) for inputting noise generated when the intake valve 28 opens and closes, and is provided in the compression chamber 27 so as to be located near the intake valve 28. Although the intake valve detection sensor 30 and the intake microphone 31 are provided in the compression chamber 27, they are arranged so as to be located above the top dead center of the piston 21.

Reference numeral 32 denotes an exhaust valve detection sensor (valve opening / closing detecting means) for detecting opening / closing of the exhaust valve 29, and outputs a detection signal when the exhaust valve 29 is opened. Reference numeral 33 denotes an exhaust microphone (operation sound detection means) for inputting noise generated when the exhaust valve 29 is opened and closed.

As shown in FIG. 3, the controller 34
Has a control circuit 37 functioning as a reversing operation sound generation unit and a sound generation control unit, a storage device 38, and an i / o module 39. The control circuit 37 is connected to the rotation detection sensor 14, the intake microphone 31, and the exhaust microphone 33, and an i / o module 39 as described later.
When the detection signals from the intake valve detection sensor 30 and the exhaust valve detection sensor 32 are input to the CPU, the noise input from the intake microphone 31 and the exhaust microphone 33 is taken in, and the inverted operation sound having a phase shift of 180 ° is generated. Then, the inversion operation sound is stored in the storage device 38. Further, the control circuit 3
Reference numeral 7 denotes a reversal operation sound that is 180 ° out of phase with the noise from the speaker 36 via the amplifier 35, that is, a noise generated when the intake valve 28 and the exhaust valve 29 are opened and closed, by generating a sound stored in the storage device 38. Mute control is performed at an optimal timing so as to cancel.

FIGS. 4A to 4C are waveform diagrams showing sound interference. FIG. 4A shows the waveform of the noise A input from the intake microphone 31 and the exhaust microphone 33.
_M or B _M are the waveforms, and the waveform of FIG.
This is a waveform of the inverted operation sound A _M ′ or B _M ′ whose phase is shifted by 180 ° with respect to the waveform of (A).

The input waveform of the operation sound A _M or B _M shown in FIG. 4A and the waveform of the inverted operation sound A _M ′ or B _M ′ shown in FIG. Fig. 4 (C)
As shown in (2), both waveforms are canceled each other, and the noise can be canceled. That is, the intake valve 28 and the exhaust valve 2
When noise is generated during the opening / closing operation of the speaker 9, the noise can be eliminated by generating, from the speaker 36, an inversion operation sound of a waveform whose phase stored in the storage device 38 is shifted by 180 ° in the housing 2.

Here, the operation of the piston 21, the intake valve 28, and the exhaust valve 29 and the pressure change during the intake process and the compression / exhaust process will be described.

FIG. 5 shows an intake process in which the piston 21 moves down in the cylinder chamber 22a. In the figure, when the piston 21 moves downward, the intake valve 28 opens and air passes through the intake port 23 and is sucked into the compression chamber 27. The opening operation of the intake valve 28 is detected by the intake valve detection sensor 30, and the operation sound at that time is converted into an electric signal by the intake microphone 31.

FIG. 6 shows a compression / exhaust process in which the piston 21 moves upward in the cylinder chamber 22a. Piston 21
Rises, the intake valve 28 closes and the exhaust valve 2
The air compressed by opening the valve 9 is supplied to the tank 5 through the exhaust port 24. The opening operation of the exhaust valve 29 is detected by an exhaust valve detection sensor 32, and the operation sound at that time is converted into an electric signal by an exhaust microphone 33.

As shown in FIG. 7, when the piston 21 moves from the bottom dead center to the top dead center, the relationship between the pressure Pa of the compression chamber 27 and the pressure Pb of the tank 5 satisfies Pa> Pb. Open, and when Pa <Pb, the exhaust valve 29 is closed.

When the relationship between the atmospheric pressure Po and the pressure Pa of the compression chamber 27 when the piston 21 moves from the top dead center to the bottom dead center is Pa <Po, the intake valve 28 opens, and Pa> Po.
When it becomes Po, the intake valve 28 closes.

That is, when the rotation speed of the motor 4 is constant, the pressure generated by the reciprocating motion of the piston 21 is also constant, so that the opening / closing operation timing of the intake valve 28 and the exhaust valve 29 is substantially constant. Therefore, when the detection signals from the intake valve detection sensor 30 and the exhaust valve detection sensor 32 are input, the control circuit 37 stores the inversion stored in the storage device 38 at a substantially constant timing corresponding to the rotation speed of the motor 4. An operation sound is generated from the speaker 36.

Next, the silencing process executed by the control circuit 37 will be described with reference to the flowchart of FIG.

In FIG. 8, when the power switch is turned on, the control circuit 37 executes step S1 (hereinafter referred to as "step").
Is omitted) to turn on the rotation change flag. And
Proceeding to S2, the processing after S3 is executed.

In S3, it is determined whether or not the motor 4 is rotating more than a certain number of times (whether the noise has reached an allowable range or more). If the rotation of the motor 4 is equal to or more than the predetermined rotation, the processing after S4 is executed.

If the rotation change flag Rflag is ON in S4, the processing of S5 to S21 is executed. However, when the rotation change flag Rflag is off in S4, S22 to S3
5 is executed.

In S5, when the intake valve flag Aflag is ON, the processing of S6 to S10 is executed. S6
Then, it is determined whether or not the detection signal As from the intake valve detection sensor 30 is off (the intake valve 28 is closed), and if the detection signal As from the intake valve detection sensor 30 is off, the process proceeds to S7 for a predetermined time. Intake valve microphone 31 to intake valve 2
8 captures the noise A _M at the time of closing of the.

Next, the process proceeds to S8, where the microphone 3 for the intake valve is used.
The phase shifted 180 ° with respect to noise A _M during closing of the intake valve 28 taken from 1, the phase 180 ° in S9
The shifted inversion operation sound is stored in the storage device 38 as A _M '. Then, in S10, the intake valve flag Aflag is turned off.

However, in S11, the detection signal As from the intake valve detection sensor 30 is turned on (the intake valve 28 is opened).
If it is, the process proceeds to S12, and the intake valve flag Aflag is turned on.

When the exhaust valve flag Bflag is ON in S13, the processing of S14 to S18 is executed. S1
4, the detection signal Bs from the exhaust valve detection sensor 32
Is turned off (exhaust valve 29 is closed), and when the detection signal Bs from the exhaust valve detection sensor 32 is off, the process proceeds to S15, and the exhaust valve microphone 33 is closed from the exhaust valve microphone 33 for a certain period of time. Capture the noise B _M of the time.

Subsequently, in S16, the noise B _M at the time of closing the exhaust valve 29 taken in from the exhaust valve microphone 33 is obtained.
The phase is shifted by 180 ° with respect to
The storage device 38 stores the inversion operation sound shifted by 80 ° as B _M ′.
To memorize. Then, the process proceeds to S18, and the exhaust valve flag B
Turn off the flag.

However, in S19, the detection signal Bs from the exhaust valve detection sensor 32 is turned on (the exhaust valve 29 is opened).
If it is, the routine proceeds to S20, where the exhaust valve flag Bflag is turned on.

When both the intake valve flag Aflag and the exhaust valve flag Bflag are off, the routine proceeds to S21, where the rotation change flag Rflag is turned off.

In S4, when the rotation change flag Rflag is off, the process proceeds to S22, and when the intake valve flag Aflag is on (set in S12), the processes of S23 to S27 are executed.

If the detection signal As from the intake valve detection sensor 30 is off (the intake valve 28 is closed) in S23,
Proceeding to 24, the reversing operation sound A _M 'stored in the storage device 38 is generated from the speaker 36 in S9, and the intake valve flag Aflag is turned off in the next S25.

However, in S26, the detection signal As from the intake valve detection sensor 30 is turned on (the intake valve 28 is opened).
If, the program proceeds to S27, where the intake valve flag Aflag is turned on.

In step S28, the exhaust valve flag Bfl
When ag is on, the processing after S29 is executed.
That is, in S29, the detection signal B from the exhaust valve detection sensor 32
When s is off (exhaust valve 29 is closed), the process proceeds to S30, in which the inversion operation sound B _M ′ stored in the storage device 38 is generated from the speaker 36 in S17, and the exhaust valve flag Bflag is set in S31. Turn off.

In S32, the exhaust valve detection sensor 3
If the detection signal Bs from 2 is ON (exhaust valve 29 is open), the routine proceeds to S33, where the exhaust valve flag Bflag is turned on.

However, in S34, when both the intake valve flag Aflag and the exhaust valve flag Bflag are off, the rotation number of the motor 4 is detected by the rotation detection sensor 14, and the rotation number of the motor 4 If it has changed, the process proceeds to S35, where the rotation change flag Rflag is turned on.

The control circuit 37 performs the above-described series of processes S1 to S3.
5 is repeatedly executed, and the intake valve 28, the exhaust valve 2
When the valve 9 is opened, the inversion operation sounds A _M ', B, which are 180 degrees out of phase with respect to the noise during the operation of the intake valve 28 and the exhaust valve 29.
_M ′ is stored in the storage device 38, and the intake valve 28 and the exhaust valve 2
Inversion sound A whose phase is shifted by 180 ° when valve 9 closes
_M ′ and B _M ′ are generated from the speaker 36.

As described above, when the noises A _M and B _M are generated during the operation of the intake valve 28 and the exhaust valve 29, the storage device 3
The inverted operation sounds A _M ′ and B _M ′ stored in
6, the noises A _M and B _M due to the opening and closing operations of the intake valve 28 and the exhaust valve 29 can be eliminated in the housing 2 as shown in the waveform diagram of FIG. Therefore, the air compressor 1 has a muffling structure in which the operation sound at the time of generating the compressed air is almost negated.

In the above embodiment, the intake valve microphone 31 and the exhaust valve microphone 33 are used for the intake valve 2.
8. The noises A _M and B _M of the exhaust valve 29 are stored. However, the present invention is not limited to this. For example, accelerations of the intake valve 28 and the exhaust valve 29 at the time of the valve opening operation are measured by an acceleration sensor, and the measured accelerations are measured. May be measured based on the noise.

In the above-described embodiment, the noises A _M and B _M on the intake side and the exhaust side are eliminated. However, the present invention is not limited to this, and the noise on either one side may be eliminated. Of course.

In the above embodiment, the processing of FIG.
Noise during operation of intake valve 28 and exhaust valve 29 every time
A_M, B_MOperation sound A whose phase is shifted by 180 °
_M’, B _M’, But not limited to this,
Inversion operation sound A stored (for example, every week)_M’, B
_M’May be updated.

Further, noises A _M and B _M during the operation of the intake valve 28 and the exhaust valve 29 are detected by the intake microphone 31 and the exhaust microphone 33, and the noise A
_M, inverted operation sound shifted 180 ° phase with respect to _{B M A M ', B M} ' may be configured to be generated from the speaker 36 while generating. In this case, there is no need to store the inversion operation sounds A _M ′ and B _M ′ as in the above-described embodiment, and the storage device 38 becomes unnecessary and the configuration can be simplified accordingly.

[0055]

As described above, in the air compressor according to the present invention, when the operation sound generated by the operation sound detection means is detected as the opening / closing operation of the intake valve or the exhaust valve, the inversion operation sound generation means is activated. An operation sound generated by the opening / closing operation of the intake valve or the exhaust valve in order to generate an inversion operation sound having a phase shifted by 180 ° from the operation sound detected by the operation sound detection means, and to generate the inversion operation sound from the speaker. It has features such as the ability to cancel the sound and to provide a muffling structure in which the operation sound is extremely suppressed.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment of an air compressor according to the present invention.

FIG. 2 is a vertical sectional view of the air compressor.

FIG. 3 is a block diagram of a controller.

FIG. 4 shows the noise of the intake valve and the exhaust valve, and the noise and the phase are 180.
FIG. 7 is a waveform diagram showing interference of a sound shifted by °.

FIG. 5 is a longitudinal sectional view showing an intake process in which a piston moves downward.

FIG. 6 is a longitudinal sectional view showing a compression / exhaust step in which a piston moves upward.

FIG. 7 shows tank pressure, compressor pressure, piston position,
FIG. 3 is a diagram showing a relationship between an intake valve opening / closing position and an exhaust valve opening / closing position.

FIG. 8 is a flowchart illustrating a process executed by a control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air compressor 2 Housing 3 Compressor main body 3A-3C Piston cylinder mechanism 4 Motor 5 Tank 12 Silencer 18 Crankshaft 19 Connecting rod 21 Piston 22 Cylinder 23 Inlet 24 Exhaust port 28 Intake valve 29 Exhaust valve 30 Intake valve detection Sensor 31 Intake microphone 32 Exhaust valve detection sensor 33 Exhaust microphone 34 Controller unit 36 Speaker 37 Control circuit 38 Storage device

Claims (1)

(57) [Claims] 1. An air compressor for generating compressed air by opening and closing an intake valve and an exhaust valve provided on a cylinder head in accordance with a reciprocating motion of a piston, wherein at least one of the intake valve and the exhaust valve is provided. Valve opening / closing detecting means for detecting the opening / closing operation of the valve; operating sound detecting means for detecting at least one of the operating sounds generated by the opening / closing operation of the intake valve or the exhaust valve for a predetermined time; A speaker provided to generate a sound toward the cylinder head; and a control means. The control means generates a reverse operation sound having a phase shifted by 180 ° from the operation sound detected by the operation sound detection means. And a sound generation control means for generating the inversion operation sound from the speaker, wherein the inversion operation sound is generated from the speaker. An air compressor is characterized in that at least one of the operation sounds generated by the opening and closing operations of the intake valve and the exhaust valve is silenced.