JP2006112375A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump which can control the occurrence of a whistle noise in a suction passage. <P>SOLUTION: When a crank bench 4 is rotated by the drive of a motor 3, each diaphragm part 14 is oscillated up and down one by one, and each pump chamber 21 is expanded and contracted one by one. When the pump chamber 21 is expanded, the air is sucked into the pump chamber 21 passing through the suction passage 31 and an intake hole 20. When the expanded pump chamber 21 is contracted, the air is discharged to the outside passing through a discharge passage 28 from a discharge hole 19. A concavity 31 shaped like a groove is provided at one part of the end edge of the opening of the suction passage 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pump in which air is supplied from a suction passage to the pump chamber when the pump chamber expands, and air in the pump chamber is discharged to a discharge passage when the pump chamber contracts.

A conventional pump includes a pump chamber formed by a diaphragm that contracts and expands, a suction hole that communicates with the pump chamber, supplies air to the pump chamber, and a discharge hole that communicates with the pump chamber and discharges air from the pump chamber. A suction valve provided between the pump chamber and the suction hole for regulating the backflow of air from the pump chamber to the suction hole, and a backflow of air from the discharge hole to the pump chamber provided between the pump chamber and the discharge hole. And a lid having a suction passage that covers the suction hole and communicates with the suction hole (see, for example, Patent Document 1). In addition, the applicant could not find prior art documents closely related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification. .
Japanese Patent Laid-Open No. 11-173273 (paragraph “0019”, FIG. 1)

  In the conventional diaphragm pump described above, there is a problem that a sound like a whistle is generated by the air passing through the suction passage. The cause of the whistling noise is not always clear. The reason considered by the inventor will be described below with reference to FIG. Since the cross-sectional area of the suction passage 40 is extremely small, the flow velocity of the air A passing through the suction passage 40 becomes high, and the suction passage as an obstacle immediately before the high-speed air A enters the suction passage 40. 40 collides with the opening edge portion 40a of the intake passage 40, and is divided into a direction along the inner wall surface 40b of the suction passage 40 and a direction along the opening end edge 40c of the suction passage 40, and turbulence is generated behind the opening edge portion 40a. This turbulent air flow generates an air vortex, that is, a Karman vortex 41, and the Karman vortex 41 is repeatedly generated and disappeared by repeated contraction and expansion of the pump chamber. It is considered that local pressure fluctuations occur in the suction passage 40 due to the repeated generation and disappearance of the Karman vortex 41, and this becomes the vibration wave S of the air and the whistling sound is generated. In this case, if the cross-sectional area of the suction passage 40 is increased, the flow rate of the air passing through the suction passage 40 is reduced, so that the generation of Karman vortices is reduced and the whistling sound can be suppressed theoretically. However, if the cross-sectional area of the suction passage 40 is increased, the opening / closing sound of the intake valve that has been silenced in the adjacent silencer chamber 42 leaks outside through the suction passage 40 and generates other noise. The cross-sectional area of the suction passage 40 could not be increased to such an extent that the occurrence of this could be suppressed.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to suppress the generation of whistling sounds.

  To achieve this object, the invention according to claim 1 includes a pump chamber that contracts and expands, a suction passage that communicates with the pump chamber, supplies air to the pump chamber, and communicates with the pump chamber. A discharge passage through which air is discharged; a suction valve that is provided between the pump chamber and the suction passage and restricts the backflow of air from the pump chamber to the suction passage; and between the pump chamber and the discharge passage. In the pump provided with a discharge valve that is provided and restricts the backflow of air from the discharge passage to the pump chamber, a recess is provided in a part of the opening edge of the suction passage.

  According to the present invention, the phase of the vibration wave of the air generated from the bottom of the recess is offset from the phase of the vibration wave of the air generated from the opening end of the suction passage, so that the vibration waves interfere with each other and cancel each other. Therefore, the generation of whistling sounds is suppressed. The reason why the whistling sound is reduced is based on the inventor's guess as described above, and is actually confirmed as a result of many experiments.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a diaphragm pump according to the present invention, where FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line I (B) -I (B) in FIG. 1A, and FIG. It is a model figure for magnifying and showing the principal part and demonstrating the cause by which a whistle blowing sound is suppressed.

  The diaphragm pump generally indicated by reference numeral 1 in FIG. 1 includes a case 2 formed in a substantially cylindrical shape, and an output shaft 3a faces the inside of the case 2 through a hole provided in the bottom of the case 2. As described above, the motor 3 is fixed by screws. Reference numeral 4 denotes a crank base formed in a small columnar shape, which is attached to the output shaft 3a of the motor 3, and a portion eccentric from the center portion attached to the output shaft 3a of the crank base 4 includes: The drive shaft 5 is fixed in an inclined state with respect to the output shaft 3a. Reference numeral 6 denotes a driving body, which is composed of a boss 7 and a plurality of driving elements 8 projecting integrally at one end of the boss 7 radially at equal angles in the circumferential direction. A drive shaft 5 is rotatably inserted into the shaft hole of the part. The plurality of driver elements 8 are inclined downward in the figure by the same angle from the center toward the tip, and mounting holes 8a for attaching piston portions of the respective diaphragm portions to be described later are provided at the respective tip portions. ing.

  Reference numeral 9 denotes a diaphragm holder formed in a cap shape. The upper plate 10 is provided with a plurality of diaphragm part holding holes 11 for holding each diaphragm part. The diaphragm holder 9, the case 2, The housing is formed by abutting open ends of each other. Reference numeral 13 denotes a diaphragm having three diaphragm portions 14. Each diaphragm portion 14 is integrally formed with a piston portion 15, and the piston portion 15 is provided with an engaging convex portion 16. This diaphragm 13 is attached to the drive body 6 and the diaphragm holder 9 by inserting each diaphragm portion 14 into the diaphragm portion holding hole 11 and attaching it to the mounting hole 8a of the driver 8 while elastically deforming the engaging convex portion 16. Retained.

  Reference numeral 17 denotes a valve holder, which is integrally provided with a partition wall 18 formed in an annular shape in plan view. A discharge hole 19 is provided inside the partition wall 18 and a suction hole 20 is provided outside. Each is provided. The valve holder 17 holds the diaphragm 13 together with the diaphragm holder 9, and three pump chambers 21 are formed by the valve holder 17 and each diaphragm portion 14. Reference numeral 22 denotes a discharge valve body that opens and closes the discharge hole 19, and reference numeral 23 denotes a suction valve body that opens and closes the suction hole 20.

  Reference numeral 24 denotes a lid formed in a substantially cap shape that covers the valve holder 17, and a discharge space that communicates with the discharge hole 19 on the inner side of the partition wall 18 between the lid 24 and the valve holder 17. 25 is formed, and a suction space 26 communicating with the suction hole 20 is formed outside. In addition, a discharge cylinder portion 27 is integrally provided at the center of the lid body 24, and a discharge passage 28 communicating with the discharge space 25 is provided in the hollow portion of the discharge cylinder portion 27. A suction passage 30 that communicates with the suction space 26 is provided at a portion that is deviated from the central portion.

  A groove-shaped recess 31 having a height H, which is a feature of the present invention, is provided in part of the opening edge of the suction passage 30 to suppress the generation of whistling noise in the suction passage 30. As shown in FIG. 1A, the recess 31 is formed in a substantially rectangular shape extending in the normal direction of the suction passage 30, and the width B is slightly smaller than the diameter of the suction passage 30 in plan view. ing. As shown in FIG. 2, the bottom 31 b of the recess 31 is formed so as to be orthogonal to the inner wall surface 30 c of the suction passage 30, and is formed in parallel with the opening edge 30 b of the suction passage 30. The lid 24, the valve holder 17, the diaphragm holder 9 and the case 2 are integrated by a through screw or a clamping spring member (not shown).

  Next, operation | movement of the diaphragm pump 1 comprised in this way is demonstrated. When the motor 3 is driven and the output shaft 3a rotates, the crank base 4 also rotates integrally. Therefore, the drive shaft 5 fixed in an inclined state with respect to the output shaft 3a at a position eccentric from the output shaft 3a is output. The shaft 3a rotates eccentrically so as to change the inclination direction. Accordingly, the three driver elements 8 of the driving body 6 rotatably supported by the drive shaft 5 are sequentially swung in the vertical direction, and the three diaphragm portions 14 of the diaphragm 13 are also swung in the vertical direction. Since the pump chamber 21 of the diaphragm section 14 moved downward is expanded, the pump chamber 21 is in a negative pressure state, and air is sucked into the pump chamber 21 from the suction passage 30 through the suction hole 20.

  When the output shaft 3a of the motor 3 further rotates, when the diaphragm portion 14 of the expanded pump chamber 21 moves upward, the pump chamber 14 contracts, so that the pressure of the air in the pump chamber 21 increases, Air is discharged to the outside from the discharge hole 19 through the discharge passage 28. Since the expansion / contraction operation of the pump chamber 21 is sequentially performed in each pump chamber 21, the air discharged from each discharge hole 19 is collected by the discharge space 25 and continuously discharged from one discharge passage 28. .

  Here, the reason why it is considered that the generation of the whistling sound in the suction passage 30 is suppressed by providing the groove-shaped recess 31 in a part of the opening end of the suction passage 30 will be described with reference to FIG. When the air A passing through the suction passage 30 collides with the opening edge 30a as an obstacle immediately before passing through the suction passage 30, the air A passes in the direction along the inner wall surface 30c of the suction passage 30 and the opening of the suction passage 30. Divided in the direction along the edge 30b, turbulence is generated behind the obstacle. This turbulence generates air vortex, that is, Karman vortex 33, and the Karman vortex 33 is repeatedly generated and disappeared in the suction passage 30 as the suction valve 23 is opened and closed by the pumping action of the pump chamber 21. Inside, a local pressure fluctuation occurs, and a vibration wave S1 of air having a wavelength λ is generated.

  On the other hand, when the air A passing through the recess 31 comes into contact with the opening edge 31a as an obstacle immediately before passing through the recess 31, the air A is directed toward the inner wall surface 30c of the suction passage 30 and the bottom 31b of the recess 31. The turbulence is generated behind the obstacle, and the Karman vortex 33 is generated. Therefore, an air vibration wave S2 having a wavelength λ is generated in the suction passage 30. Since the vibration wave S2 is out of phase with the vibration wave S1 by the depth H of the recess 31, the waves interfere with each other and cancel each other. Therefore, the vibration wave S1 and the vibration wave S2 are attenuated, and the whistling sound is generated. It is thought to be suppressed. In this case, if the vibration wave S1 and the vibration wave S2 have the same waveform, that is, the wavelength and the amplitude are the same, theoretically, the depth H of the recess 30 is set to 1/2 of the wavelength λ of the vibration waves S1 and S2. Therefore, the vibration wave S1 can be eliminated and the cause of the whistling sound can be cut off.

  3A and 3B show a second embodiment of the present invention, where FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along line III (B) -III (B) in FIG. . In the second embodiment, a suction cylinder part 35 is erected at a position deviated from the center part of the lid 24, and the hollow part 36 of the suction cylinder part 35 communicates with the suction space 26. The hollow portion 36 forms a suction passage. A recess 37 formed in a groove shape is provided in a part of the opening edge of the suction passage 36. With this configuration, when the air passes through the suction passage 36, the two vibration waves S1 and S2 whose phases are shifted in the suction passage 36 are generated in the same manner as in the first embodiment described above. Therefore, the generation of whistling noise is suppressed.

  In the present embodiment, the example in which the suction passage 30 is provided in the lid 24 has been described. However, the present invention can also be applied to a diaphragm pump in which a suction passage is formed in a swinging drive body. In this embodiment, the example in which the pump chamber is contracted and expanded by swinging the drive body in the vertical direction has been described. However, the pump chamber is controlled by swinging the drive body in the left-right direction. It can also be applied to diaphragm pumps that contract and expand. Further, in the present embodiment, the diaphragm pump provided with the lid 24 has been described, but the lid 24 may not be provided, and in that case, the diaphragm pump may be part of the opening edge of the suction hole 20 of the valve holder 17. A recess may be provided. Further, although three diaphragms have been described, the present invention can be applied to two or less or four or more diaphragms. In addition, the diaphragm pump that contracts and expands the pump chamber using a diaphragm has been described. However, the pump type may be a piston pump. In short, the intake passage through which air is sucked by the contraction and expansion of the pump chamber and the intake passage are opened and closed. It can be applied to any pump provided with a valve body.

The diaphragm pump which concerns on this invention is shown, The same figure (A) is a top view, The same figure (B) is the I (B) -I (B) sectional view taken on the line in the same figure (A). It is a model figure for magnifying and showing the principal part of the diaphragm pump which concerns on this invention, and explaining the principle by which a whistling sound is suppressed. The second embodiment of the present invention is shown, in which FIG. (A) is a plan view and FIG. (B) is a sectional view taken along line III (B) -III (B) in FIG. It is a model figure for demonstrating generation | occurrence | production of a whistling sound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Diaphragm pump, 3 ... Motor, 6 ... Drive body, 13 ... Diaphragm, 14 ... Diaphragm part, 20 ... Suction hole, 21 ... Pump chamber, 22 ... Discharge valve, 23 ... Suction valve, 26 ... Suction space, 28 ... Discharge passage, 30, 36 ... suction passage, 31, 37 ... recess, 35 ... suction cylinder.

Claims (1)

A pump chamber that contracts and expands, a suction passage that communicates with the pump chamber, supplies air to the pump chamber, a discharge passage that communicates with the pump chamber and discharges air from the pump chamber, and the pump chamber and the suction passage Between the pump chamber and the discharge passage, and a discharge valve that is provided between the pump chamber and the discharge passage to restrict the backflow of air from the discharge passage to the pump chamber. A pump comprising a valve, wherein a recess is provided in a part of the opening edge of the suction passage.

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