JPH0331913B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrically driven vibratory air compression device which is used as an air pressure source for adjusting the height of a vehicle, for example, and which has been improved to be particularly compact.

In conventional vibrating air compressors, the vibrations of the mechanical system and the electrical system do not match due to time delays caused by the inertia of the mechanical system, making it difficult to drive efficiently. Figures 1 and 2 show the relationship between the piston amplitude, input voltage, and input current during sine wave driving and square wave driving. When the input current is positive, the electrical system receives electromagnetic force in the suction direction. If it is negative, electromagnetic force is applied in the discharge direction. In other words, in the hatched areas in FIGS. 1 and 2, electromagnetic force acts in a direction opposite to the direction of movement of the piston, which reduces the amplitude and discharge amount of the piston, resulting in a problem of inefficiency. In the figure, A indicates the suction stroke, B indicates the discharge stroke, A indicates the suction side, B indicates the equilibrium point, and C indicates the discharge side.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a highly efficient vibratory air compressor by reducing the mismatch between vibrations between the mechanical system and the electrical system.

In order to achieve this objective, the present invention provides a rest period for the voltage applied to the electrical system, and the length of the rest period when the applied voltage switches from positive to negative and when it switches from negative to positive is different. It can be set arbitrarily.

Next, an embodiment in which the present invention is used as an air pressure source for adjusting the vehicle height of a vehicle will be described based on the drawings.

FIG. 3 shows a cross-sectional structure of the compressor 10 constituting the compression device. Upper and lower casings 12 and 13 are provided in a sealed state with respect to a cylindrical sleeve 11 to constitute a pressure accumulator container 14. A compressor main body 15 is provided inside the pressure accumulator container 14, and this main body 15 includes a support spring 16,
17 within the container 14.

The compressor main body 15 includes a sleeve 18 made of a ferromagnetic material arranged coaxially with the sleeve 11,
An upper cylinder 19 and a lower cylinder 20 are fixedly set inside both ends of the sleeve 18, respectively. This upper and lower cylinder 19,2
0 is arranged coaxially and a piston 21 is inserted therein, and the cylinders 19, 2 are connected by a container passage 22 formed in the central axis of the piston 21.
0 is connected.

A discharge valve 23 is provided inside the upper cylinder 19, and this valve 23 is normally connected to the opening facing the piston 21 by a spring 25 interposed between it and a retainer 24 provided at the outer opening of the cylinder 19. It is set to close the section.
A compressed air chamber is formed between the valve 23 and the retainer 24. And this air chamber is
It communicates with the retainer 24 and a discharge pipe 26 that penetrates the casing 12 and is drawn out to the outside of the pressure accumulator container 14 .

Further, the lower cylinder 20 is provided with a check valve mechanism 28 that communicates with an intake pipe 27 that penetrates the lower casing 13 and is drawn out to the outside, so that only intake air is introduced into the lower cylinder 20. Configure.

A flange portion 29 is provided in a portion of the piston 21 located between the upper cylinder 19 and the lower cylinder 20 in the form of a brim. This flange 29 is a cylindrical stay 3 set outside the upper cylinder 19.
Moving coils 31 and 32 are attached to the outside of this stay 30 in a state parallel to the axis. Here, the upper cylinder 1 corresponds to the positions of the moving coils 31 and 32.
A stator core 33 is provided on the outer peripheral surface of the ferromagnetic sleeve 18 , and annular permanent magnets 34 and 35 are provided on the inner surface of the ferromagnetic sleeve 18 so as to face the stator 33 . The permanent magnets 34 and 35 are magnetized in the radial direction, and the magnetization directions are opposite to each other. In addition, the moving coils 31, 3
2 also have their winding directions reversed and are interconnected.

The piston 21 is supported between the upper and lower cylinders 19 and 20 by means of a flange 29 and springs 36 and 37 so as to be able to vibrate in the axial direction.

Excitation current to the moving coils 31 and 32 is given from terminals 38a and 38b, and terminal 3
8a is a conductor 39, a conductive plate 40, a spring 3
7. It is connected to the coils 31 and 32 through the conductive plate 41, and the terminal 38b is connected to the coils 31 and 32 through the conductor 42, the conductive plate 43, the spring 36, and the conductive plate 44. In the figure, 45 is a communication pipe penetrating the upper casing 12, and 46 is a pressure sensor that detects the pressure inside the pressure accumulator container 14.

FIG. 4 shows the overall configuration of a compression device using the compressor 10 as described above. be used as. Further, the discharge pipe 26 communicates with an air dryer 50 via a pipeline 49 of an air passage switching circuit 48.
An output pipeline 51 from the compressor 10 is connected to a communication pipe 45 of the compressor 10 via a check valve 52 in the air passage switching circuit 48 . Pipeline 49 above
is further branched via a check valve 53, and supplies a driving compressed air source to an actuator 54 that drives, for example, a vehicle height adjustment device, and a communication pipe 45 is connected to this actuator 54 via an on-off valve 55. has been done. 56 is an exhaust valve.

FIG. 5 shows the moving coils 31 and 32 of the compressor 10.
When the pressure sensor 46 detects that the pressure in the pressure accumulator container 14 has fallen below the specified set pressure, the oscillation starts when the pressure sensor 46 receives the signal from the pressure sensor 46. A pulse signal is oscillated from a circuit (not shown). This pulse signal is input to the binary counter 47, which increments the count by one each time the pulse signal is input, and sends the corresponding address signal to the ROM 4.
8 and the pause period setting circuit 51. Here, the binary counter 47 is an n-bit counter, and the vibrating air compressor is operated at a power supply frequency f.
(Hz), the binary counter 47
The pulse frequency of the signal input to , that is, the pulse frequency at point A in the figure, is 2 ⁿ ·f (Hz).

A binary signal corresponding to a rectangular wave is recorded in the ROM 48, and a binary counter 47
It receives an address signal from , and outputs a rectangular wave binary signal recorded at the same address to the digital-to-analog converter 49 .

In the digital-to-analog converter 49, the ROM4
The binary signal from 8 is converted into an analog signal, and the level of the converted analog signal is converted by the differential amplifier 50. The level-converted signal, that is, the signal at point B in the figure, is branched into two, one of which is supplied to the NOR circuit 59 and the other to the NOR circuit 60 through the inverter 58. Further, the relationship between the address signal outputted from the binary counter 47 and the output waveform outputted from the differential amplifier 50 is as shown in FIG. For example, if the voltage application suspension period is from address 0 to address K (0≦K≦N) and from address N+1 to address P (N≦P≦Z), The corresponding address and the address signal output from the binary counter 47 are constantly compared. Then, while the address signal of the address corresponding to the voltage application suspension period is detected, the suspension period setting circuit 51 outputs a signal to the NOR circuits 59 and 60.

The NOR circuit 59 outputs a signal obtained by NORing the signal output from the differential amplifier 50 and the signal output from the idle period setting circuit 51, and this signal controls ON-OFF of the transistors 54 and 57. . Further, the NOR circuit 60 outputs a signal obtained by NORing the signal output from the differential amplifier 50 and passed through the inverter 58 and the signal output from the pause period setting circuit 51. Controls ON-OFF of 56. And these transistors 54, 55, 5
6 and 57, voltages having waveforms having rest periods t ₁ and t ₂ as shown in FIG. 7 are input to the movable coils 31 and 32. (A: Suction side, B: Discharge side) The waveforms of the signals at points A, B, C, D, E, and F in FIG. 5 are as shown in FIG.

Next, the effects of the rectangular wave drive of this embodiment will be explained based on experimental results in comparison with the conventional one.

The isoflow diagram shown in ^FIG . 9 shows the voltage rest period time ratio (t ₁ /T ₁ ,
Measurements were made by varying t ₂ /T ₂ , where T ₁ =T ₂ ). In this embodiment, the voltage application suspension periods t ₁ and t ₂ can be arbitrarily determined by arbitrarily setting the address corresponding to the suspension period of the suspension period setting circuit 51.

In conventional vibrating air compression equipment, t ₁ /T ₁ = t ₂ /T ₂
As a result, only the flow rate along the straight line (X) in FIG. 9 could be obtained. Therefore, in order to obtain a larger flow rate than before, it is only necessary to set t ₁ /T ₁ = t ₂ /T ₂ within the region indicated by the diagonal line Y, and in particular, t ₁ /T ₁ = 0.2 to 0.4,
The highest flow rate can be obtained by setting t ₂ /T ₂ =0.5 to 0.65.

In addition, the pause period ratio is t ₁ /T ₁ = 0.3, t ₂ /T ₂ =
0.5, the piston amplitude when applying a square wave,
FIG. 10 shows the input voltage waveform and input current waveform.
As can be seen from this figure, the portion that generates electromagnetic force in the opposite direction to the direction of piston movement indicated by hatching is reduced compared to the conventional case, indicating a highly efficient drive.

As explained above, by using the vibratory air compressor of the present invention, it is possible to reduce the mismatch between vibrations between the mechanical system and the electrical system, and it is possible to perform efficient compression.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the relationship between piston amplitude, input voltage, and input current of a conventional vibrating air compressor, Figures 3 to 9 relate to embodiments of the present invention, and Figure 3 shows the A vertical cross-sectional view of the machine part, Figure 4 is an overall configuration diagram, Figure 5 is a diagram showing the drive circuit, and Figure 6 is an address signal output from the binary counter and an output waveform output from the differential amplifier. 7 is a diagram showing the input waveform input to the moving coil, FIG. 8 is a diagram showing the signal at the point in FIG. 5, FIG. 9 is an isoquant diagram, and FIG. FIG. 10 is a diagram showing the relationship among piston amplitude, input voltage, and input current. 10... Compressor, 14... Pressure accumulator container, 15...
... Compressor main body, 16, 17 ... Support spring,
19... Upper cylinder, 20... Lower cylinder,
21...Piston, 22...Air passage, 26...
Discharge pipe, 27... Suction pipe, 31, 32... Moving coil, 33... Stator core, 34, 35... Permanent magnet, 45... Communication pipe, 46... Pressure switch, 100... Drive circuit.

Claims (1)

[Claims] 1 A pressure accumulator container that stores compressed air, a piston mechanism that is installed inside this container and reciprocated by an alternating current, and the reciprocating movement of this piston mechanism sucks air from outside the pressure accumulator container and discharges the compressed air from the discharge port. and a drive circuit for supplying an alternating current to the piston mechanism, and when the alternating current switches from positive to negative and from negative to positive, the alternating current changes to an arbitrary rest period. A vibrating air compression device characterized by: