JP2007309293A - Diaphragm pump and connection structure of pipe passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a four-valve diaphragm pump capable of securing liquid-tightness of a connection part of a flow passage formed by a cylindrical protrusion, a fitting hole and an O-ring with high reliability, durability and assembly performance in the diaphragm pump wherein a suction port and a delivery port communicated with a suction flow passage and a delivery flow passage of one of a pair of housings fastening a diaphragm, and a pair of cylindrical protrusion communicated with the suction port and the delivery port or a fitting hole are formed in one of the pair of the housings, a pair of fitting holes or a cylindrical protrusion communicated with a suction flow passage and a delivery flow passage of the other housing and fitted with the pair of the cylindrical protrusions or the fitting hole is formed on the other housing, and the O-ring is interposed between the cylindrical protrusion and the fitting hole. <P>SOLUTION: When an outside diameter of the O-ring in a free condition fitted to an outer periphery of the cylindrical protrusion is (d) and an end diameter of the fitting hole is D, D is set to be larger than (d) and a diameter of a tapered hole formed in the fitting hole is smaller as going to an inner side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diaphragm pump and a pipe connection structure.

The diaphragm pump forms a pump chamber (variable volume chamber) by the diaphragm, and a pair of check valves (inlet side check allowing fluid flow to the pump chamber) in a pair of flow paths connected to the pump chamber. A discharge-side check valve that allows fluid flow from the valve and the pump chamber. When the diaphragm is vibrated, the volume of the pump chamber changes, and the suction side check valve opens in the stroke when the volume increases, and the discharge side check valve opens in the stroke when the volume decreases. It is done. The diaphragm is made of an elastic (vibrating) material such as rubber or a piezoelectric vibrator.
JP-A-10-288120 Japanese Patent Laid-Open No. 11-182413 JP 2002-70732 A Japanese Patent Laid-Open No. 2003-232283

  As described above, this diaphragm pump repeats the operation of opening the suction side check valve in the stroke in which the volume of the pump chamber is expanded and opening the discharge side check valve in the stroke in which the volume is reduced. Is inevitable.

  The present applicant has proposed a diaphragm pump in which the pulsation at the discharge port is a problem and the pulsation cycle is halved (Japanese Patent Laid-Open No. 2005-337068). In this diaphragm pump, a pair of pump chambers are formed above and below the diaphragm by the diaphragm, while a single suction port and a single discharge port are provided, and the suction ports are respectively provided between the pair of pump chambers and the suction port. First and second suction side check valves that allow fluid flow from the port to the pair of pump chambers but do not allow fluid flow in the opposite direction are provided between the pair of pump chambers and the discharge port, respectively. There are provided first and second discharge-side check valves that allow fluid flow from a pair of pump chambers to the discharge port but do not allow fluid flow in the opposite direction (four-valve diaphragm pump).

  In this four-valve diaphragm pump, basically, upper and lower housings sandwiching the diaphragm are respectively formed with recesses for forming an upper pump chamber and a lower pump chamber, and these are laminated in order, and a pair of pump chambers are formed on the upper housing and the lower housing. It can be configured by forming a flow path that connects the suction port and the discharge port. However, in the 4-valve diaphragm pump being developed by the present applicant, the liquid-tightness of the connection portion of the flow path formed across the upper housing and the lower housing, or the liquid-tightness of the suction flow path and the discharge flow path is highly reliable. How to secure it in terms of durability and durability is a problem. Furthermore, high assemblability is required for mass-produced products.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a four-valve diaphragm pump capable of ensuring the liquid tightness of the connecting portion of the flow path formed across the upper housing and the lower housing with high reliability, durability and assemblability. To do. It is a further object of the present invention to provide a pipe connection structure that is excellent in assemblability and that is free from pinching of the O-ring during assembly in a pipe connection structure using an O-ring.

  The four-valve diaphragm pump of the present invention includes a pair of housings that sandwich a vibrating diaphragm, a recess that forms a pump chamber between the diaphragm, a suction-side check valve, and a discharge-side check valve in each pump chamber. A suction flow path and a discharge flow path that communicate with each other through a valve are formed, and a suction port and a discharge port that communicate with the suction flow path and the discharge flow path of the one housing are provided in one of the pair of housings, and the suction port And a pair of cylindrical protrusions or fitting hole portions respectively communicating with the discharge port, and the other housing communicates with the suction passage and the discharge passage of the other housing, A diaphragm pump in which a pair of fitting holes or cylindrical protrusions that fit into the fitting part or the fitting hole part is formed, and an O-ring is interposed between the cylindrical protrusion and the fitting hole part, Free fit on the outer periphery of the cylindrical protrusion When the outer diameter of the O-ring is d and the end diameter of the fitting hole is D, D> d is set, and a tapered hole having a smaller diameter is formed in the fitting hole. It is characterized by being.

  It is preferable that a tapered shaft portion corresponding to the tapered hole portion of the fitting hole portion is formed in the cylindrical protrusion, and the O-ring is compressed and held between the tapered hole portion and the tapered shaft portion.

  In addition, if the cylindrical protrusion and the fitting hole are formed with constant diameter portions that are fitted to each other at the tip of the taper shaft and the tip of the taper hole, respectively, the axes of both are easily aligned. be able to.

  The taper of the tapered hole portion (taper shaft portion) may be, for example, 20 to 45 ° with respect to the axis.

  Further, in the present invention, more generally, the tubular protrusion is formed on one of a pair of members having a conduit to be connected, and the tubular protrusion is fitted on the other. In an aspect of a pipe connection structure in which a fitting hole portion connected to a path is formed and an O-ring is interposed between the outer periphery of the cylindrical protrusion and the fitting hole portion, an O-ring is provided on the outer periphery of the cylindrical protrusion. When the outer diameter of the O-ring in the fitted free state is d and the end diameter D of the fitting hole is set to D> d, and the tapered part is smaller in diameter toward the inner part of the fitting hole. It is characterized by having formed.

  According to the present invention, in the four-valve diaphragm pump, the liquid-tightness of the connecting portion of the flow path formed across the upper housing and the lower housing is ensured with high reliability and durability without sacrificing assembly. can do. Even in a general pipe connection structure using an O-ring, high assemblability, liquid-tight reliability and durability can be ensured.

  In the illustrated embodiment, the present invention is applied to a four-valve diaphragm pump proposed by the applicant of the present invention in Japanese Patent Application Laid-Open No. 2005-337068. One embodiment will be described with reference to FIGS. This diaphragm pump has an upper housing 20U that sandwiches a piezoelectric vibrator (diaphragm) 10 at the center, and a lower housing 20L.

  The upper housing 20U and the lower housing 20L are made of a molded product of a resin material, and a suction port 21 and a discharge port 22 made of a completely cylindrical body and projecting from each other are provided on the lower housing 20L side. The upper housing 20U and the lower housing 20L basically have symmetrical shapes except for the structure around the suction port 21 and the discharge port 22. First, the common (symmetric) structure will be described. As shown in FIGS. 1, 4, and 5, the upper housing 20U (lower housing 20L) has an inner surface (the surface on the piezoelectric vibrator 10 side is the inner surface, and the opposite is the opposite). A pump chamber forming recess 23U (23L) is formed on the outer surface, and a suction flow path recess 24U (24L) and a discharge flow path recess (recess) 25U (25L) whose outer surfaces are opened on the outer surface. Is formed. A deformed O-ring holding groove 23U1 (23L1) is formed on the outer periphery of the pump chamber forming recess 23U (23L).

  The suction flow path recess 24U (24L) extends from the outer side of the upper housing 20U (lower housing 20L) toward the center, and the flow path communicates with the pump chamber forming recess 23U (23L) at the center side end. A hole 26U (26L) is formed. The discharge flow path recess 25U (25L) extends substantially in parallel with the suction flow path recess 24U (24L), and a flow path hole 27U (communication with the pump chamber formation recess 23U (23L) is provided at the center side end thereof. 27L) is drilled. A suction side umbrella (check valve) 28U (28L) is attached to the flow path hole 26U (26L), and a discharge side umbrella (check valve) 29U (29L) is installed in the flow path hole 27U (27L). Is installed.

  The lower housing 20L communicates with the suction port 21 and the discharge port 22, and communicates with the outer end portions of the suction flow path recess 24L and the discharge flow path recess 25L (FIGS. 2, 4, and 5). ) Is drilled. In the upper housing 20U, communication holes 33 and 34 (FIGS. 3, 4, and 4) are connected to the outer end portions of the suction flow path recess 24U and the discharge flow path recess 25U so as to match the positions of the communication holes 31 and 32. 5) is drilled.

  The communication holes 31 and 33 and the communication holes 32 and 34 are pipes that are liquid-tightly connected to each other. As shown in FIGS. 4, 5, and 6, the communication holes 33 and 34 are provided in the upper housing 20 </ b> U. And cylindrical projections 35 and 36 are formed so as to be coaxial with each other. On the other hand, fitting holes 37 and 38 for receiving the cylindrical projections 35 and 36 are formed in the lower housing 20L coaxially with the communication holes 31 and 32.

  The cylindrical protrusion 35 and the fitting hole 37 (cylindrical protrusion 36 and fitting hole 38) have the same structure. As best shown in FIG. 6, the cylindrical protrusion 35 (36) includes, in order from the tip, a small-diameter constant-diameter portion 35a (36a), a large-diameter tapered shaft portion 35b (36b), and a large-diameter constant-diameter portion 35c. (36c). On the other hand, the fitting hole portion 37 (38) has a small diameter constant diameter hole 37a (38a), a stepped enlarged diameter tapered hole portion 37b (38b) and a large diameter constant diameter hole portion 37c (38c) in order from the back. is doing. An O-ring 39 is provided between the diameter-expanded tapered shaft portion 35b (36b) of the cylindrical protrusion 35 (36) and the stepped diameter-expanded tapered hole portion 37b (38b) of the fitting hole 37 (38). Compressed and held.

  The O-ring 39 is connected in advance to the cylindrical protrusion 35 (36) when the upper housing 20U and the lower housing 20L are connected (see FIG. 7A). When the outer diameter of the O-ring 39 in this free state is d, the end diameter D of the fitting hole 37 (38) (large diameter constant diameter hole 37c (38c)) is set to D> d. (FIG. 7A). As described above, when the outer diameter of the O-ring 39 and the end diameter of the large-diameter constant-diameter hole 37c (38c) are set, the cylindrical protrusion 35 (36) of the upper housing 20U is made clear as shown in FIG. When inserting and coupling to the fitting hole 37 (38) of the lower housing 20L, the O-ring 39 is hardly caught. In the fully inserted state, the O-ring 39 is compressed and held between the enlarged diameter tapered shaft portion 35b (36b) and the stepped enlarged diameter tapered hole portion 37b (38b), thereby maintaining liquid tightness. . The small diameter constant diameter portion 35a (36a) and the large diameter constant diameter portion 35c (36c), and the small diameter constant diameter hole 37a (38a) and the large diameter constant diameter hole portion 37c (38c) are fitted to each other to ensure coaxiality. To do.

  FIG. 10 shows a case where the outer diameter of the O-ring 39 is larger than the end diameter of the fitting hole 37 (38) as a reference example. When the outer diameter of the O-ring 39 is large as described above, the O-ring 39 is likely to be sandwiched between the upper housing 20U and the lower housing 20L due to slight dimensional errors (manufacturing errors and assembly errors). Liquid-tight holding reliability is impaired. In particular, since this diaphragm pump is aimed at miniaturization to the limit, such pinching of the O-ring is a problem, and according to this embodiment, liquid tightness can be maintained without the problem of pinching of the O-ring. Can do.

  In addition, in this embodiment, a pair of the cylindrical protrusion 35 and the fitting hole 37, and the cylindrical protrusion 36 and the fitting hole 38 are present in parallel with each other. For this reason, as shown in FIG. 8, the manufacturing error of the inter-axis distance X also causes the pinching. According to this embodiment, it is possible to absorb an error in the distance between the axes. The outer diameter d of the O-ring 39 in the free state and the size of the end diameter D of the fitting hole 37 (38) (large diameter constant diameter hole 37c (38c)) are specifically manufactured by these. Determined in consideration of errors and assembly errors.

  When the O-ring 39 is compressed between the enlarged diameter tapered shaft portion 35b (36b) and the stepped enlarged diameter tapered hole portion 37b (38b), the repulsive force of the O ring 39 causes the upper housing 20U and the lower housing to be compressed. A force in the separation direction acts between 20L. This force should be as small as possible. For this reason, it is preferable that the inclination | tilt angle (alpha) (FIG. 6, FIG. 7) with respect to the axis line of the diameter expansion taper shaft part 35b (36b) and the step diameter expansion taper hole part 37b (38b) shall be 20 degrees-45 degrees. If it is larger than 45 °, the separating force becomes too large, and if it is smaller than 20 °, it becomes difficult to increase the end diameter of the fitting hole 37 (38), and the problem of the O-ring being caught is solved. Becomes difficult. The large diameter constant diameter portion 35c (36c) and the large diameter constant diameter hole portion 37c (38c) may not be provided.

  The piezoelectric vibrator 10 is sandwiched and held between the two housings with the deformed O-ring 41 inserted in the O-ring holding groove 23U1 (23L1) of the upper housing 20U (lower housing 20L). The piezoelectric vibrator 10 is composed of a bimorph-type piezoelectric vibrator, and vibrates when an alternating electric field is applied between a shim at a central portion in the thickness direction and piezoelectric bodies stacked on the front and back of the shim. Such a piezoelectric vibrator 10 is well known and has nothing to do with the gist of the present invention, so further description including the feeding structure will be omitted.

  The suction flow path recess 24U (24L) and the discharge flow path recess 25U (25L) of the upper housing 20U (lower housing 20L) are liquid-tightly closed by the lid plate 42 (FIG. 1), thereby separating the suction flow path and the discharge flow path. Constitute. The lid plate 42 is a member made of a molded product of a synthetic resin material common to the suction flow path recess 24U (24L) and the discharge flow path recess 25U (25L), and its liquid-tight structure is taken as an example of the suction flow path recess 24U. This will be described with reference to FIGS.

  Within the suction flow path recess 24U, a shallow step portion 24U1, a deep groove portion 24U2, and a central middle-high portion 24U3 are formed in a closed curve in order from the outside along the shape of the suction flow path recess 24U. An O-ring guide taper portion 24U4 is formed between the shallow step portion 24U1 and the deep groove portion 24U2. On the other hand, on the lid plate 42, an outer peripheral thin plate portion 42a and an insertion protrusion portion 42b are formed in a closed curve so as to correspond to the shallow step portion 24U1 and the deep groove portion 24U2, and on the outer periphery side of the insertion protrusion portion 42b, An O-ring holding recess 42c is formed. The inner peripheral surface of the insertion protrusion 42b is in contact with the center middle / high part 24U3.

  An O-ring 43 is held in the O-ring holding recess 42c, and is held and compressed between the wall of the deep groove portion 24U2 and the insertion protrusion 42b to maintain liquid tightness. The repulsive force of the O-ring 43 tends to deform the insertion protrusion 42b inward, but the center middle and high portion 24U3 comes into contact with the inner end of the insertion protrusion 42b, and the insertion protrusion 42b is prevented from being deformed. In this way, the deformation force applied to the insertion protrusion 42b of the lid plate 42 by the O-ring 43 is received by the center middle / high portion 24U3 of the suction flow path recess 24U, thereby improving the liquid-tight reliability of the lid plate 42 portion. Can do. The lid plate 42 is joined to the contact portion between the outer thin plate portion 42a and the shallow step portion 24U1 by appropriate means such as laser welding, ultrasonic welding, or adhesive.

  In the diaphragm pump having the above-described configuration, the chamber formed between the piezoelectric vibrator 10 and the pump chamber forming recess 23U of the upper housing 20U is defined as the pump chamber A, and the pump chamber forming recess 23L of the piezoelectric vibrator 10 and the lower housing 20L. Assuming that the chamber formed between the two chambers is a pump chamber B, the operation is as follows. That is, when the piezoelectric vibrator 10 is elastically deformed (vibrated) in the forward and reverse directions, the volume of one of the pump chambers A and B increases and the other volume decreases. In the process of increasing the volume of the pump chamber A (decreasing the volume of the pump chamber B), the suction side umbrella 28U is opened, fluid flows into the pump chamber A from the suction port 21, and fluid in the pump chamber B is discharged. The side umbrella 29L is opened and flows out to the discharge port 22 (see FIG. 11B). Conversely, in the stroke in which the volume of the pump chamber A decreases (the volume of the pump chamber B increases), the suction-side umbrella 28L is opened and fluid flows into the pump chamber B from the suction port 21, and the fluid in the pump chamber A Opens the discharge-side umbrella 29U and flows out to the discharge port 22 (see (A)). Therefore, the pulsation cycle in the discharge port 22 can be shortened (halved compared to the case where the pump chamber is formed only in one of the upper and lower sides of the piezoelectric vibrator 30).

  The present invention is directed to a seal structure that ensures the liquid-tightness of the fitting portions of the cylindrical protrusions 35 and 36 and the fitting hole portions 37 and 38 of the above embodiment with high assemblability and durability. The formation mode of the suction channel and the discharge channel, the umbrella (check valve), the piezoelectric vibrator, and the like is merely an example.

It is a perspective view of the disassembled state which shows one Embodiment of the diaphragm pump by this invention. It is an inner surface figure of a lower housing. It is an external view of an upper housing. It is sectional drawing which follows the IV-IV line of FIG.2 and FIG.3 in an assembly state. It is sectional drawing which follows the same VV line. It is a disassembled cross-sectional perspective view of a connection pipe line part. (A), (B), (C) is sectional drawing which shows the assembly process of a connection pipe line part. It is sectional drawing before the coupling | bonding of an upper housing and a lower housing which follows the VIII-VIII line of FIG. It is a cross-sectional perspective view showing the relationship between a suction channel recess (discharge channel recess) and a lid plate that closes the recess liquid-tightly. It is sectional drawing corresponding to FIG. 7 which shows the comparative example of a connection pipe line structure. (A), (B) is a conceptual diagram in the vibration direction from which the diaphragm of the 4-valve diaphragm pump to which this invention is applied is different.

Explanation of symbols

10 Piezoelectric vibrator (diaphragm)
20U Upper housing 20L Lower housing 21 Suction port 22 Discharge port 23U 23L Pump chamber forming recess 24U 24L Suction passage recess 25U 25L Discharge passage recess 24U1 Shallow step portion 24U2 Deep groove portion 24U3 Center middle and high portion 24U4 O-ring guide taper portion 26U 26L Flow Channel hole 27U 27L Channel hole 28U 28L Suction side umbrella 29U 29L Discharge side umbrella 31 32 Communication hole (lower housing side)
33 34 Communication hole 35 36 Cylindrical protrusion 35a 36a Small diameter constant diameter part 35b 36b Large diameter taper shaft part 35c 36c Large diameter constant diameter part 37 38 Fitting hole part 37a 38a Small diameter constant diameter hole 37b 38b Stepped large diameter tapered hole Portion 37c 38c large-diameter constant-diameter hole 39 O-ring 41 deformed O-ring 42 lid plate 42a outer peripheral thin plate portion 42b insertion protrusion 42c O-ring holding recess 43 O-ring

Claims (5)

A pair of housings that sandwich the vibrating diaphragm, a recess that forms a pump chamber between the diaphragm, and a suction flow that communicates with each pump chamber via a suction-side check valve and a discharge-side check valve, respectively. Forming a channel and a discharge channel,
One of the pair of housings includes a suction port and a discharge port communicating with the suction flow path and the discharge flow path of the one housing, and a pair of cylindrical protrusions or holes communicating with the suction port and the discharge port, respectively. Form the
The other housing is formed with a pair of fitting hole portions or cylindrical protrusion portions that communicate with the suction passage and the discharge passage portion of the other housing and fit into the pair of cylindrical protrusion portions or fitting hole portions. ,
A diaphragm pump in which an O-ring is interposed between the pair of cylindrical protrusions and the fitting hole,
When the outer diameter of the O-ring fitted in the outer periphery of the cylindrical projection is d and the end diameter of the fitting hole is D, D> d, and the fitting hole A diaphragm pump characterized in that a tapered hole portion having a smaller diameter toward the back portion is formed in the portion. 2. The diaphragm pump according to claim 1, wherein a tapered shaft portion corresponding to a tapered hole portion of the fitting hole portion is formed on the cylindrical protrusion, and the tapered shaft portion is provided between the tapered hole portion and the tapered shaft portion. A diaphragm pump that compresses and holds the O-ring. 3. The diaphragm pump according to claim 2, wherein a small-diameter constant-diameter portion is formed in the cylindrical projection and the fitting hole, respectively, to be fitted to each other at the tip of the taper shaft and the tip of the taper hole. Diaphragm pump. 4. The diaphragm pump according to claim 1, wherein a taper of the tapered hole portion is 20 to 45 ° with respect to an axis. 5. A cylindrical protrusion connected to the pipe is formed on one of a pair of members having a pipe to be connected, and a fitting hole connected to the pipe is formed on the other. In the pipe connection structure in which an O-ring is interposed between the outer periphery of the cylindrical protrusion and the fitting hole, the outer diameter of the O-ring in a free state in which the O-ring is fitted to the outer periphery of the cylindrical protrusion Where d is the end diameter D of the fitting hole, and D> d, and the fitting hole is formed with a tapered portion having a smaller diameter toward the back. Connection structure.