JP2012002134A - Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a side effect problem caused by the vibration of a movable part during ultrasonic welding.SOLUTION: The pump includes a fixed shaft rotatably supporting an impeller via a bearing, and a casing welded with a separation plate by ultrasonic welding and housing the impeller in a space with the separation plate. An axial end face of a casing side of the bearing disposed at an impeller inner periphery is slidably contacted to a bearing plate prevented from rotating by engagement with a D-cut part provided at an end of a casing side of the shaft supported in both axial ends by the separation plate and the casing. A distance from the other face of the bearing plate supported by the casing in an axial one face to an edge of an end of the D-cut part in the shaft is larger than a movable distance of the bearing in the axial direction of the shaft.

Description

  The present invention relates to a pump in which members constituting a pump chamber are joined by ultrasonic welding, and more particularly to a pump in which a DC brushless motor for driving is integrally provided.

  Various types of pumps exist, and a typical example is a centrifugal brush driven by a DC brushless motor. As shown in FIG. 8, the rotor unit 5 is integrally formed with the impeller 7 and includes the permanent magnet 6, the stator unit 3 formed by winding the coil 1, and the coil The pump chamber 18, in which the rotor portion 5 is rotatably supported by the shaft 12, is arranged in each arrangement space between the rotor portion 5 and the stator portion 3. It is formed as a space surrounded by the separation plate 2 that divides the gas and the casing 8 having the suction port 16 and the discharge port 17.

  As shown in FIG. 9, the shaft 12 on which the bearing 14 fixed to the inner periphery of the rotor portion 5 is rotatably arranged is provided with a plane 12b parallel to the axial direction and a plane 12c perpendicular to the axial direction at both ends. The D-cut portion 12a on one end side is supported by a shaft support 2a provided on the separating plate 2, and the D-cut portion 12a on the other end side is supported by a shaft support 8a provided on the casing 8. It is supported. Since the shaft support 2a has a D-cut shape that matches the cross-sectional shape of the D-cut portion 12a of the shaft 12, the shaft 12 is prevented from rotating by the shaft support 2a. Further, a cushioning material 15 is provided between the shaft support 8a and the other end surface of the shaft 12, so that the axial direction of the shaft 12 is suppressed.

  Further, a bearing plate 13 inserted through the shaft 12 is disposed in the gap between the end surface of the bearing 14 on the casing 8 side and the shaft support 8a. The bearing plate 13 does not rotate with respect to the shaft 12 by having a D-shaped hole that matches the cross-sectional shape of the D-cut portion 12 a of the shaft 12.

  This pump rotates the rotor portion 5 (the impeller 7) by generating a rotating magnetic field in the stator portion 3 by energization control of the coil 1 of the stator portion 3, and supplies liquid into the pump chamber 18 from the suction port 16. At the same time, the liquid is pressurized and discharged from the discharge port 17.

  While the impeller 7 is rotating, the vicinity of the center of the impeller 7 from the suction port 16 becomes negative pressure, and the outer periphery of the impeller 7, the outer periphery of the rotor unit 5, and the impeller 7 are increased by the liquid pressurized by the rotation of the impeller 7. A positive pressure is formed on the back side. For this reason, a differential pressure is generated before and after the impeller 7 in the axial direction, and a force G acting on the impeller 7 toward the casing 8 is applied. Due to this force G, the end surface on the casing 8 side in the axial direction of the bearing 14 rotates and slides on the bearing plate 13 while the impeller 7 rotates.

  Since the end surface of the bearing 14 on the side of the separation plate 2 is in contact with the end surface of the shaft support 2a, it impedes the rotation of the impeller 7, so that the total length of the bearing 14 and the thickness of the bearing plate 13 are added The length between the end surface of the shaft support 8a on the casing side and the end surface of the shaft support 2a on the separation plate 2 side is slightly longer than that, and the impeller 7 is rotated between the bearing 14 and the end surface of the shaft support 2a. A gap C is generated in the gap.

  By the way, the casing 8 surrounding the pump chamber 18 and the separation plate 2 are generally connected by a fixing tool such as a screw and sealed by packing. In this case, however, the number of parts increases and the packing is increased. There is a problem such as water leakage due to aging of foreign matter or packing with time. This point can be solved by connecting the casing 7 and the separation plate 2 by welding as shown in Patent Document 1. The above-mentioned Patent Document 1 shows that the casing and the separation plate are connected by spin welding. However, when ultrasonic welding is performed, the following problem is newly generated.

  That is, ultrasonic welding mainly applies vibration energy to the pressure-bonded joint surfaces of components to be joined by generating longitudinal vibrations by ultrasonic waves of 20 kHz or higher, and the welding margin provided on the joint surfaces by frictional heat. It is melted and melted and bonded instantly, and when the separator plate and casing that make up the pump chamber are ultrasonically welded, several shapes and forms can be taken. Usually, a fixed form called a shear joint is taken.

  10 and 11 are sectional views before welding in the case of the shear joint type, and FIGS. 12 and 13 are sectional views after welding. The casing 8 is received by the receiving jig 35, and the separation plate 2 placed on the casing 8 is pressurized downward by the ultrasonic horn 32 on the casing 2 side.

  In the state before welding, the welded portion taper 8 c of the casing 8 is in contact with the welded portion edge 2 c of the separation plate 2. In this state, if ultrasonic wave is oscillated simultaneously with pressurization by the ultrasonic horn 32 and vibration energy is propagated to the welded part through the ultrasonic horn 32, the welded part edge 2c is melted by the welding length D by frictional heat. Then, the melted portion E is formed in the state shown in FIGS.

  Here, the impeller 7 (rotor portion 5) in a state before welding has a bearing 14 mounted on a shaft support 8a of the casing 8 via a bearing plate 13 by its own weight, and is separated from the upper end surface of the bearing 14. There is a gap of C + D between the end surface of the shaft support 2a of the plate 2.

  The ultrasonic vibration applied for welding causes each component to vibrate. However, since both the impeller 7 and the bearing plate 13 are movable in the axial direction with respect to the shaft 12, a slight amount of the shaft support 8a is slightly affected. The movement is amplified by the vibration and moves up and down greatly in the axial direction. As shown in FIG. 14, this vertical movement initially occurs with the maximum amplitude (C + D). The amplitude decreases as the welded portion progresses, and finally becomes the amplitude of C.

  Immediately after the oscillation of the ultrasonic vibration, when the rotor portion 5 reaches the highest point as shown in FIG. 14B by the above vertical movement, the plane 12c at the end of the D-cut portion 12a on the casing 8 side of the shaft 12 The edge portion 12d, which is a portion where the outer peripheral surface of the shaft 12 intersects, is exposed from the bearing 14.

  Further, the shaft 12 and the bearing plate 13 are made of ceramic or SUS material. However, when a ceramic material is used in order to ensure particularly good slidability, the thickness of the bearing plate 13 is reduced. By making it thinner than the distance from the edge portion 12d of the D-cut portion 12a of the shaft 12 to the end surface of the shaft support 8a, a gap F is provided between the edge portion 12d of the shaft 12 and the bearing plate 13, and the edge portion 12d Although the bearing plate 13 is not interfered with, when the rotor portion 5 is separated from the bearing plate 13 as described above, the bearing plate 13 becomes movable in the axial direction by the gap F, and the ultrasonic wave At the time of oscillation, the bearing plate 13 also moves up and down. At this time, the bearing plate 13 repeatedly contacts the exposed edge portion 12d of the shaft 12 to generate slight chipping at the edge portion 12d. Let me It was a. Such a situation may also occur when an axial impact is applied to the pump.

  When ceramic fragments generated by chipping enter the sliding surface of the bearing 14 and the bearing plate 13 and are strongly pressed by the end surface of the bearing 14 on the casing 8 side by the vertical vibration of the rotor portion 5, If the pump is operated as it is, the sliding resistance increases due to ceramic debris caught on the bearing sliding surface, and the specified pump performance cannot be satisfied. It was.

JP2009-221942A

  It is an object of the present invention to provide a pump that can suppress the vibration of the movable part that occurs during ultrasonic welding from causing a new problem.

  According to the first aspect of the present invention, there is provided an impeller having a magnetic follower disposed in a pump chamber, a fixed shaft that rotatably supports the impeller through a bearing, and the magnetic A magnetic drive unit that rotates the impeller by applying magnetism to the driven unit, a separation plate that partitions the magnetic drive unit from the pump chamber, and a separation plate that is welded to the separation plate by ultrasonic welding. A casing that forms the pump chamber in between, and the rotation is prevented by engagement with a D-cut portion provided at an end portion on the casing side of the shaft that is supported at both ends in the axial direction by the separation plate and the casing. In the pump in which the axial end surface on the casing side of the bearing disposed on the inner periphery of the impeller is in sliding contact with the bearing plate, the casing is provided with one axial surface rather than the movable distance of the bearing in the axial direction of the shaft. Above the other side of the supported bearing plate It is characterized in that to increase the distance to the edge of the end of the D-cut portion in the axial.

  The invention of claim 2 of the present application includes an impeller that has a magnetic follower and is disposed in the pump chamber, a fixed shaft that rotatably supports the impeller via a bearing, and the magnetic A magnetic drive unit that rotates the impeller by applying magnetism to the driven unit, a separation plate that partitions the magnetic drive unit from the pump chamber, and a separation plate that is welded to the separation plate by ultrasonic welding. A casing that forms the pump chamber in between, and the rotation is prevented by engagement with a D-cut portion provided at an end portion on the casing side of the shaft that is supported at both ends in the axial direction by the separation plate and the casing. In the pump in which the axial end surface on the casing side of the bearing disposed on the inner periphery of the impeller is in sliding contact with the bearing plate, a surface parallel to the axial direction in the D-cut portion of the shaft and an outer peripheral surface of the shaft Tapered by connecting with inclined surfaces inclined with respect to the axial direction It is characterized in that is.

  In any pump, it is preferable to provide a relief with a larger bearing inner diameter on the inner peripheral surface of the bearing casing side end. A tapered shape with a small diameter may be used. In any case, providing the relief improves the slidability between the shaft and the bearing.

  Moreover, it is preferable that the part located in the outer periphery of the said bearing of an impeller is provided with the circulation hole which penetrates an impeller to an axial direction. Since the circulating hole reduces the differential pressure generated before and after the impeller in the axial direction, the force acting on the sliding contact surface between the bearing and the bearing plate is reduced, and good sliding characteristics can be obtained.

  In particular, if at least three or more circulation holes installed in the impeller are formed at equal intervals around the axis of the impeller, the posture during rotation of the impeller is also stabilized, so that even better sliding characteristics are obtained. can get.

  In the first aspect of the invention, when ultrasonic vibration is applied to the separation plate and the casing for ultrasonic welding, the impeller and the bearing plate vibrate in the axial direction. Therefore, even if the shaft and the bearing plate are made of ceramic, chipping does not occur, and as a result, the pump performance due to chips generated by chipping. It can suppress that the fall of this occurs.

  In the invention of claim 2, even if the bearing plate contacts the end of the D-cut portion of the shaft, there is no sharp edge portion, so that no chipping occurs. Can be suppressed.

It is sectional drawing in an example of embodiment of this invention. It is sectional drawing of the impeller vicinity when an impeller is located in the uppermost point by the vibration in another example. Furthermore, it is sectional drawing of an impeller vicinity when an impeller is located in the uppermost point by the vibration in another example. It is a front view of the impeller which shows a reflux hole. It is a front view of the impeller which shows the other example of a reflux hole. It is sectional drawing of the impeller vicinity when an impeller is located in the uppermost point by the vibration in another example. It is sectional drawing of an impeller vicinity when an impeller is located in the uppermost point by the vibration in another example. It is sectional drawing of a prior art example. It is a perspective view of a shaft same as the above. It is sectional drawing before ultrasonic welding. It is sectional drawing of the welding part vicinity before ultrasonic welding. It is sectional drawing after ultrasonic welding. It is sectional drawing of the welding part vicinity after ultrasonic welding. (a) (b) is sectional drawing which shows the vertical vibration of the impeller by the ultrasonic wave at the time of welding.

  The present invention will be described in detail based on an example of the embodiment. As shown in FIG. 1, the basic configuration is the same as that of the conventional example, and the inside of the pump chamber 18 surrounded by the separation plate 2 and the casing 8. The rotor 5 is integrally formed with the impeller 7, and one end of the rotor 5 is supported by the shaft support 2 a of the separation plate 2 and the other end is supported by the shaft support 8 a of the casing 8. The shaft 12 is rotatably supported via a bearing 14. A permanent magnet 6 is fixed to the outer peripheral portion of the rotor portion 5 in which an impeller 7 having a large number of blades 7a is formed on one end side in the axial direction. 3 is disposed.

  The stator portion 3 formed as a plurality of coils 1 wound around the stator core 22 is positioned and fixed by fixing a hook-shaped protrusion 22a provided on the stator core 22 to the separation plate 2 with a core fixing screw 23. The coil 1 is connected to a control unit 4 fixed to the separation plate 2 with screws or the like by caulking terminals or tie pins. The control unit 4 rotates the rotor unit 5 (the impeller 7) including the permanent magnet 6 around the shaft 12 by generating a rotating magnetic field by controlling energization to the plurality of coils 1.

  The shaft 12 includes D-cut portions 12a and 12a at both ends in the axial direction. The D-cut portion 12a on one end side is supported by a shaft support 2a having a cross-sectional shape provided on the separation plate 2 and having a D-cut shape. The end-side D-cut portion 12 a is supported by a shaft support 8 a provided in the casing 8. The distance between the bottom surface of the shaft support 2a and the bottom surface of the shaft support 8a is slightly longer than the total axial length of the shaft 12, and a cushioning material made of an elastic material is provided between the shaft support 8a and the other end surface of the shaft 12. By the compression arrangement 15, the axial direction of the shaft 12 is suppressed.

  A bearing plate 13 is disposed between the bearing 14 fixed to the inner peripheral surface of the rotor portion 5 and the shaft support 8a. The bearing plate 13 does not rotate with respect to the shaft 12 by forming a hole having a shape corresponding to the D-cut portion 12 a of the shaft 12 at the center.

  In the pump in which the stator 3 as the magnetic drive unit is arranged in a region partitioned by the separation plate 2 from the pump chamber 18 in which the rotor unit 5 (the impeller 7) as the magnetic follower unit is arranged, the stator unit 3 When the impeller 7 is rotated by generating a rotating magnetic field, the liquid is sucked into the pump chamber 18 from the suction port 16 provided in the casing 8, and the liquid whose pressure is increased with the rotation of the impeller 7 is the same. It is discharged from a discharge port 17 provided in the casing 8. At this time, the rotation of the impeller 7 causes negative pressure in the vicinity of the center of the impeller 7 from the suction port 16, and positive pressure acts on the rear surface side of the impeller 7 by the liquid pressurized by the rotation of the impeller 7. Therefore, differential pressure acts on the front and rear in the axial direction of the impeller 7, and the axial load G to the casing 8 side is applied to the impeller 7 as described above. The end surface of the bearing 14 is rotationally slid on the bearing plate 13.

  The axial load G generated by the pump operation is all applied to the sliding surfaces of the bearing plate 13 and the bearing 14, and if this surface pressure becomes too high, the sliding portion of the bearing 14 is adversely affected. Abnormal wear or the like of the bearing 14 occurs. For this purpose, here, a circulating hole 7c that penetrates the rotor portion 5 in the axial direction is provided in a portion located between the outer periphery of the bearing 14 and the magnet 6 in the rotor portion 5. Due to the presence of the circulation hole 7c that allows the casing 8 side and the separation plate 2 side of the impeller 7 to communicate with each other, the pressure difference is relaxed and the load generated on the bearing plate 13 and the bearing 14 is reduced. The recirculation hole 7c is small and about φ1.5 is appropriate even if it is large from φ1.0. Further, it is preferable to provide a plurality around the axis of the shaft 12 at equal intervals. This is because the posture of the rotating impeller 7 is stabilized, so that good sliding characteristics can be obtained.

  4 shows a case where three circulation holes 7c are provided at equal intervals, and FIG. 5 shows a case where four circulation holes 7c are provided at equal intervals. However, two or five or more circulation holes 7c are provided. Also good. However, if the cross-sectional area and the number of the circulation holes 7c are too large, the loss of liquid circulation increases and the pump efficiency decreases. Therefore, it is necessary to balance the setting of the size and number of the circulation holes 7c.

  Further, since the distance from the end surface of the shaft support 8a to the end surface of the shaft support 2a is longer by C than the total length of the bearing 14 and the thickness of the bearing plate 13, the bearing 14 is rotated during the rotation of the impeller 7. The end face of the shaft support 2a is prevented from contacting.

  Further, the distance F from the other surface of the bearing plate 13 in contact with the end surface of the shaft support 8a to the edge portion 12d at the end of the D-cut portion 12a on the casing 8 side of the shaft 12 is determined from the distance C. It is also long.

  Further, the separation plate 2 and the casing 8 here are fixed and sealed by ultrasonic welding as described in the conventional example, but the welding length D and C are added at the time of welding. The F is made longer than the combined length C + D.

  For this reason, even when the bearing 14 of the rotor portion 5 moves to the separation plate 2 side due to the vibration during ultrasonic welding and the impact in the axial direction of the shaft 12 applied to the pump, as shown in FIG. The edge portion 12d of the shaft 12 is still in the inner peripheral position of the bearing 14 and is not exposed to the bearing plate 13 side than the end face of the bearing 14, so that even if the bearing plate 13 moves in the axial direction, The edge portion 12d is not hit, and chipping of the edge portion 12d, which is a problem when the shaft 12 is made of ceramic, does not occur.

  However, when the length of the D-cut portion 12a is increased, the impeller 7 rotates in a state of moving to the casing 8 side due to the differential pressure in the pump operation state. 12a is present, and the length of the portion of the entire inner periphery of the bearing 14 that is received by the shaft 12 is shortened, and the slidability due to the twisting of the bearing 14 with respect to the shaft 12 may be reduced.

  In this regard, as shown in FIG. 2, a relief 14d having a slightly larger inner diameter may be provided on the inner peripheral surface of the end portion of the bearing 14 on the casing 8 side. As the relief 14d, as shown in FIG. 3, the end inner peripheral surface of the bearing 14 on the casing 8 side may be a tapered surface.

  If the relief 14d is too large, the area of the sliding surface of the bearing 14 decreases and the surface pressure of the sliding portion in the axial direction during pump operation increases, which may adversely affect the slidability of the bearing 14. However, in such a case, it is effective to provide the circulation hole 7c for reducing the differential pressure acting on the impeller 7 as described above.

  Regarding the point of preventing chipping of the edge portion 12d, it is shown in FIG. 6 or 7 instead of connecting the outer peripheral surface of the shaft 12 and the surface parallel to the axial direction of the D-cut portion 12 with a surface orthogonal to the axial direction. Thus, the edge portion 12d may have an obtuse angle by connecting the inclined surfaces inclined with respect to the axial direction into a tapered shape. Even in this case, even when the bearing plate 13 is exposed during ultrasonic welding or axial impact, the edge portion 12d is not a sharp edge, so that no chipping occurs. In this case, if the end surface of the bearing 14 contacts the bearing plate 13 when the bearing 14 is on the casing 8 side, the obtuse edge portion 12d has an obtuse edge portion 12d when the bearing 14 is on the separation plate 2 side as shown in FIG. 14 may be exposed from the end face.

  Regardless of the type of the D-cut portion 12a of the shaft 12, the shaft 12 as shown in the illustrated example having the D-cut portions 12a at both ends considers the D-cut at both ends in consideration of assembly workability. The parts 12a and 12a may have the same size and shape.

DESCRIPTION OF SYMBOLS 1 Coil 2 Separation plate 3 Stator part 4 Control part 5 Rotor part 6 Permanent magnet 7 Impeller 8 Casing 12 Shaft 13 Bearing plate 14 Bearing

Claims (7)

An impeller disposed in the pump chamber having a magnetic follower, a fixed shaft that rotatably supports the impeller via a bearing, and magnetism applied to the magnetic follower. A magnetic drive section for rotating the impeller, a separation plate that partitions the magnetic drive section from the pump chamber, and a casing that is welded to the separation plate by ultrasonic welding to form the pump chamber between the separation plate A bearing plate that is supported by a D-cut portion provided at an end portion on the casing side of the shaft that is supported at both ends in the axial direction by the separation plate and the casing, on the inner periphery of the impeller A pump in which the axial end surface on the casing side of the bearing disposed is in sliding contact,
The distance from the other surface of the bearing plate supported by the casing to the edge portion of the end of the D-cut portion in the shaft is larger than the movable distance of the bearing in the axial direction of the shaft. A pump characterized by An impeller disposed in the pump chamber having a magnetic follower, a fixed shaft that rotatably supports the impeller via a bearing, and magnetism applied to the magnetic follower. A magnetic drive section for rotating the impeller, a separation plate that partitions the magnetic drive section from the pump chamber, and a casing that is welded to the separation plate by ultrasonic welding to form the pump chamber between the separation plate A bearing plate that is supported by a D-cut portion provided at an end portion on the casing side of the shaft that is supported at both ends in the axial direction by the separation plate and the casing, on the inner periphery of the impeller A pump in which the axial end surface on the casing side of the bearing disposed is in sliding contact,
A pump characterized in that a surface parallel to the axial direction in the D-cut portion of the shaft and an outer peripheral surface of the shaft are connected by an inclined surface inclined with respect to the axial direction to form a taper shape.   The pump according to claim 1 or 2, wherein a relief having a larger bearing inner diameter is provided on an inner peripheral surface of an end portion on a casing side of the bearing.   4. The pump according to claim 3, wherein the relief provided on the inner peripheral surface of the end portion of the bearing on the casing side has a constant inner diameter.   4. The pump according to claim 3, wherein the relief provided on the inner peripheral surface of the end portion of the bearing on the casing side has a tapered shape with a diameter decreasing toward the back of the bearing.   The pump according to any one of claims 1 to 5, wherein a portion of the impeller located on the outer periphery of the bearing is provided with a circulation hole penetrating the impeller in the axial direction.   The pump according to claim 6, wherein the at least three or more circulation holes installed in the impeller are formed at equal intervals around the axis of the impeller.

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