JP2009156241A - Centrifugal pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal pump easy to secure coaxial arrangement of an impeller and a driving shaft. <P>SOLUTION: The centrifugal pump 1 includes a housing 3 fitted to an engine block 2, a driving shaft 7 turnably supported by the housing, and an impeller 11 as an impeller fixed to one end of the driving shaft. The impeller is integrally formed with a disc-like base 12, a plurality of blade parts 13 cut and stood on a peripheral side thereof and bent in the axial direction in predetermined positions in the circumferential direction of the base, and a shaft part 14 protruded along the axial direction in the inner peripheral part of the base by pressing a metal plate. At the same time, the driving shaft is formed into a hollow cylindrical shape. The impeller is fixed to the driving shaft by fitting the shaft part in the inner periphery of one end of the driving shaft. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of a centrifugal pump applied to, for example, a water pump used in a cooling device for an automobile engine.

  In a water pump applied to a cooling device for an automobile engine, for example, an embodiment of this type of centrifugal pump, a drive shaft formed in a hollow shape for the purpose of reducing the weight of the pump or reducing the cost has been proposed in recent years. For example, one described in Patent Document 1 below is known.

  Briefly, the water pump is inserted through an outer surface of the engine block, a substantially concave housing fixed to the outer surface of the engine block, and an inner periphery of a cylindrical portion provided at the bottom of the housing. A hollow cylindrical drive shaft rotatably supported on the inner periphery of the cylindrical portion; and an impeller attached to one end of the drive shaft and housed in a pump chamber defined by the housing and the engine block. The impeller is rotated by the rotational driving force of the engine transmitted through a pulley attached to the other end of the drive shaft.

  The impeller has a plurality of blade portions provided at a predetermined interval in the circumferential direction and guides the fluid flowing into the inner circumferential side to the outer circumferential side based on centrifugal force, and a cylindrical fitting portion is provided at the center position thereof. Is provided. The impeller is connected to the drive shaft via a rod-like connecting shaft whose one end is fitted and fixed to the fitting portion of the impeller and the other end is fitted and fixed to one end of the drive shaft. ing.

In addition, a suction port that opens to the inner peripheral side of the impeller is formed in the outer surface of the engine block, and a discharge port that opens to the outer peripheral side of the impeller is formed in the housing. As a result, when the impeller rotates, the fluid sucked into the inner peripheral side of the impeller through the suction port is guided to the outer peripheral side of the impeller through the blade portion by centrifugal force and discharged from the discharge port. It has become so.
JP 2003-364658 A

  With this configuration, the conventional water pump is configured to connect the impeller to the drive shaft via the connection shaft. Therefore, when the water pump is assembled, the impeller, the connection shaft, and the drive shaft are separated from each other. There is a need to secure the coaxial of the person.

  However, since the impeller, the connecting shaft, and the drive shaft are individually manufactured, not only machining errors occur in the three parties, but also the assembly errors of the three parties are accumulated by assembling them. Therefore, the technical problem that it is difficult to ensure the coaxiality of the three parties has been invited.

  The present invention has been devised in view of the actual situation of the conventional water pump, and an object of the present invention is to provide a centrifugal pump capable of facilitating ensuring the coaxiality between the impeller and the drive shaft.

  According to the present invention, a shaft portion extending in the axial direction is integrally formed on the inner portion of the impeller, and the shaft portion is fitted and fixed to the inner periphery of one end portion of a hollow drive shaft, thereby driving the impeller and the impeller. It is characterized by connecting shafts.

  Embodiments of a centrifugal pump according to the present invention will be described below with reference to the drawings.

  In each of the following embodiments, the centrifugal pump according to the present invention is applied to a water pump used in a cooling device for an automobile engine as in the prior art, and this water pump is provided on one side of an engine block. The cooling water is circulated in the engine block using the rotational driving force of the crankshaft of the engine as a power source.

  1 to 4 show a first embodiment of the present invention. As shown in FIG. 1, the water pump 1 has a concave housing 3 attached to one side of an engine block 2, and the housing A pump chamber 4 is defined between the engine block 3 and the engine block 2.

  The housing 3 is formed with a cylindrical portion 5 protruding in the axial direction, and an inner peripheral surface 5a of the cylindrical portion 5 is formed in a cylindrical shape constituting a ball bearing mechanism having a driving shaft 7 as an inner ring. The outer ring member 6 is fixed by press-fitting. Further, a drive shaft 7 formed in a substantially hollow cylindrical shape is penetrated on the inner peripheral side of the outer ring member 6, and two raceway grooves are formed on the opposing surface of the drive shaft 7 and the outer ring member 6. 7a and 6a are provided in parallel along the circumferential direction. A plurality of rolling elements 8 arranged at equal intervals in the circumferential direction are interposed between the opposed raceway grooves 6a and 7a, and the drive shaft 7 is connected to the cylinder via the bearing mechanism. The part 5 is rotatably supported.

  Further, the bearing mechanism is provided with annular first and second seal members 21 and 22 between both ends of the outer ring member 6 and the drive shaft 7, respectively. Grease for smooth rolling of the rolling elements 8 is enclosed in a cylindrical space defined between the radial directions of the both.

  The first seal member 21 is interposed between one end portion of the outer ring member 6 and one end portion of the drive shaft 7. The first seal member 21 is not restrained by a seal member 23 to be described later and is not restrained by the inner peripheral portion of the cylindrical portion 5. While exhibiting a waterproof function against the moisture of the cooling water that has entered slightly, it plays a role of holding the grease sealed in the cylindrical space inside.

  On the other hand, the second seal member 22 is interposed between the other end portion of the outer ring member 6 and the other end portion of the drive shaft 7 to prevent intrusion of dust and the like from the outside of the housing 3, and Similar to the first seal member 21, it plays a role of holding the grease sealed in the cylindrical space.

  An impeller 11 connected to one end of the drive shaft 7 facing the pump chamber 4 is rotatably accommodated and disposed in the pump chamber 4, and the impeller 11 is disposed on a side portion of the engine block 2. The suction port 9 is formed so as to be directed substantially in the center of the engine block 2 and sucks the cooling water flowing through the engine block 2. Further, a discharge port (not shown) through which cooling water urged based on the centrifugal force generated with the rotation of the impeller 11 is discharged is formed in the side portion of the pump chamber 4. The suction port 9 may be provided in the housing 3 so as to be directed substantially to the center of the impeller 11 as shown in FIG.

  On the other hand, the other end of the drive shaft 7 facing the outside of the housing 3 is linked to the crankshaft of the engine via a belt (not shown) and transmits the rotational driving force of the crankshaft to the drive shaft 7. The pulley 10 is fixedly attached by press fitting or the like.

  The impeller 11 is integrally formed by pressing a metal plate, and a base 12 formed in a substantially disk shape, and an outer peripheral side is cut and raised at a predetermined position in the circumferential direction of the base 12 to be axial. A plurality of blade portions 13 that are bent to the opposite side and the drive shaft 7 from the outer surface side (the engine block 2 side) toward the inner surface side (the housing 3 side) at the center position of the base portion 12 And a cylindrical shaft portion 14 projecting from the shaft, and the tip end portion of the shaft portion 14 is press-fitted into the inner periphery of one end portion of the drive shaft 7 to be coupled to the drive shaft 7.

  The base 12 is formed in a substantially flat shape, and a fitting recess 12 a that is recessed from the inner surface to the outer surface is formed in the outer peripheral region of the base end edge of the shaft portion 14. And this fitting recessed part 12a fits the one end part of the sealing member 23 mentioned later.

  The shaft portion 14 is formed by drawing so as to push the outer surface of the base portion 12 toward the inner surface side by the press work, and is formed in a substantially bottomed cylindrical shape. In addition, at the distal end portion of the shaft portion 14, two-surface width portions 14 a and 14 a having a so-called two-surface width shape as shown in FIG. 2 are provided in a range where the one end portion of the drive shaft 7 is fitted. ing.

  On the other hand, the inner surface of one end of the drive shaft 7 is also provided with two-surface width portions 7b and 7b that engage with the two-surface width portions 14a and 14a of the shaft portion 14, and the drive shaft 7 is provided with such an engagement structure. A so-called detent is suppressed to prevent the shaft portion 14 from slipping in the circumferential direction, so that the drive shaft 7 and the impeller 11 rotate integrally.

  The engagement structure is not limited to the engagement structure having the two-sided width shape, and for example, the engagement structure having a rectangular shape as shown in FIG. 3 or the engagement shape having a polygonal shape as shown in FIG. A non-circular engagement structure such as a structure can exhibit the above-described detent action regardless of its shape.

  Further, an annular protrusion 14b that is engaged with one end edge of the drive shaft 7 is formed slightly projecting radially outward on the tip end side of the shaft section 14, and the annular protrusion 14b is formed on the drive shaft 7. It is possible to position the axial position of the shaft portion 14 with respect to the drive shaft 7 by engaging with one end edge of the shaft.

  Further, a seal member 23 for preventing cooling water from entering the bearing mechanism is fitted to the outer periphery of the base end portion of the shaft portion 14. The seal member 23 has a substantially cylindrical shape, and has one end fitted into the fitting recess 12a provided in the base 12 as described above.

  The seal member 23 is formed with an annular lip 23a protruding at a substantially central position in the axial direction. The other end of the seal member 23 is in close contact with the base end edge of the cylindrical portion 5. It is inserted in the inner periphery of the base end part of the cylindrical part 5.

  From the above, according to this embodiment, since the shaft portion 14 is integrally formed in the impeller 11, when the impeller 11 is assembled to the drive shaft 7, the drive shaft 7 and the shaft portion 14 are assembled. Therefore, the assembly workability of the both 7 and 11 can be improved as compared with the conventional structure in which the impeller and the drive shaft are connected by the connecting shaft. As a result, the number of assembling steps related to the assembling work can be reduced, which can contribute to a reduction in the manufacturing cost of the pump.

  In addition, since the impeller 11 is formed by press working, the shaft portion 14 can be formed simultaneously with the blade portion 13 and the like. Therefore, compared to the conventional configuration in which the impeller and the connecting shaft are individually manufactured, the processing is performed. Man-hours can also be reduced. Therefore, also from this viewpoint, the manufacturing cost of the pump can be reduced.

  In the case of the present embodiment, since the drive shaft 7 and the impeller 11 are directly assembled, it is possible to reduce a processing error accumulated during the assembly. 11 can improve the assembly accuracy.

  FIG. 5 shows the second embodiment of the present invention, the basic configuration is the same as that of the first embodiment, and the difference is that the impeller 11 is the same as that of the first embodiment. Thus, the metal plate is not formed by pressing, but is formed by injection molding a resin material.

  That is, the impeller 11 includes the base portion 12 formed in a substantially disc shape, and a plurality of blade portions 13 protruding along the axial direction at predetermined locations in the circumferential direction on the outer peripheral side of the base portion 12. A columnar shaft portion 14 that protrudes so as to face the drive shaft 7 toward the cylindrical portion 5 side is integrally provided at the center of the inner surface of the base portion 12.

  The shaft portion 14 is provided with a fitting groove 14c along the circumferential direction in a region fitted to the inner periphery of one end of the drive shaft 7, and the fitting groove 14c is fitted with the fitting groove 14c. A metal piece 15 formed in a shape corresponding to the groove 14c is fitted and fixed. If it demonstrates concretely, this metal piece 15 is what is called an insert, Comprising: At the time of the injection molding of the impeller 11, it is integrated simultaneously. Thereby, the press-fitting strength of the shaft portion 14 with respect to the drive shaft 7 is ensured, and the shaft portion 14 is prevented from coming off from the drive shaft 7.

  Therefore, according to this embodiment, the same effect as that of the first embodiment, which is derived by integrally configuring the shaft portion 14 in the impeller 11, can be obtained. Since the entire 11 is made of a resin material, the entire pump can be further reduced in weight compared to the first embodiment in which the impeller 11 is formed of metal.

  Furthermore, since the impeller 11 according to the present embodiment is also formed by injection molding a resin material, the shaft portion 14 can be formed at the same time when the impeller 11 is formed. Similar to the embodiment, the number of processing steps can be reduced as compared with the conventional configuration.

  FIG. 6 shows a third embodiment of the present invention, the basic configuration of which is the same as that of the second embodiment, except that the two-surface width portions 7b and 7b and the shaft of the drive shaft 7 are different. The engagement structure composed of the two-surface width portions 14 a and 14 a of the portion 14 is abolished, and instead the inner peripheral surface of the drive shaft 7 and the outer peripheral surface of the shaft portion 14 are fixed by an adhesive 16.

  Therefore, according to this embodiment, it is not necessary to provide a retaining mechanism such as the insert in the second embodiment on the shaft portion 14 by adopting a simple coupling means called adhesion. Furthermore, since it is not necessary to provide a rotation prevention mechanism for the shaft portion 14 with respect to the drive shaft 7, the shaft portion 14 can be more easily fixed to the drive shaft 7. Therefore, the assembly workability of the both 7 and 14 can be further improved.

  In addition, in the present embodiment, since the above-described detent mechanism is not required between the drive shaft 7 and the shaft portion 14, the rotation of the both 7, 14 is performed when the both 7, 14 are assembled. It is possible to ensure a relative degree of freedom in the direction. Therefore, the assembling workability of the both 7 and 14 can be further improved.

  The present invention is not limited to the configuration of each of the above embodiments. For example, in the second embodiment, as a retaining mechanism for the shaft portion 14 with respect to the drive shaft 7, instead of the insert, As shown in FIG. 7, an engaging protrusion 14 d protrudes along the outer peripheral surface of the tip end portion of the shaft portion 14, while the engaging protrusion 14 d extends along the inner peripheral surface of one end portion of the drive shaft 7. An engaging groove 7c to be engaged may be provided, and the engaging protrusion 14d may be engaged with the engaging groove 7c.

  Such a retaining mechanism can also be configured by providing the engagement groove 7c on the shaft portion 14 side and the engagement protrusion 14d on the drive shaft 7 side.

  Furthermore, in this retaining mechanism, as shown in FIG. 8, a caulking portion 7d is provided at a portion overlapping one end portion of the drive shaft 7 in the radial direction with the shaft portion 14, and the drive shaft 7 is connected to the shaft. It is also possible to adopt a configuration that caulks to the portion 14. In this case, not only can the shaft 14 be prevented from coming off from the drive shaft 7 more reliably, but also the coupling strength between the both 7 and 14 can be improved, and between the both 7 and 14 can be improved. The occurrence of relative slip can be prevented more reliably.

  Although not specifically shown, the engagement structure shown in FIGS. 7 and 8 can be applied to the first and third embodiments, and in this case. However, the same operational effects as when the engagement structure is applied to the second embodiment can be obtained.

It is principal part sectional drawing of the pump which shows 1st Embodiment of the centrifugal pump which concerns on this invention, and demonstrates the principal part of this invention. It is the sectional view on the AA line of FIG. It is the sectional view on the AA line of FIG. 1 which shows the 1st modification of the 1st Embodiment of this invention. It is the sectional view on the AA line of FIG. 1 which shows the 2nd modification of the 1st Embodiment of this invention. It is principal part sectional drawing of the pump which shows 2nd Embodiment of the centrifugal pump which concerns on this invention, and demonstrates the principal part of this invention. It is principal part sectional drawing of the pump which shows 3rd Embodiment of the centrifugal pump which concerns on this invention, and demonstrates the principal part of this invention. It is a principal part expanded sectional view of FIG. 5 which shows the 1st modification of the 2nd Embodiment of this invention. FIG. 6 is an enlarged cross-sectional view of a main part of FIG. 5 showing a second modification of the second embodiment of the present invention. It is principal part sectional drawing of the pump which shows the other examples of the 1st Embodiment of this invention.

Explanation of symbols

1. Water pump (centrifugal pump)
DESCRIPTION OF SYMBOLS 3 ... Housing 7 ... Drive shaft 11 ... Impeller 12 ... Base part 13 ... Blade | wing part 14 ... Shaft part

Claims (7)

A drive shaft rotatably supported by the housing;
An impeller fixed to one end of the drive shaft and discharging the fluid sucked from the axial direction in the circumferential direction by centrifugal force;
While forming the drive shaft in a hollow shape, integrally forming a shaft portion extending along the axial direction on the inner portion of the impeller,
A centrifugal pump characterized in that the shaft portion of the impeller is fitted and fixed to the inner periphery of one end portion of the drive shaft. The impeller is integrally formed by pressing a metal plate,
A base formed in a substantially disc shape;
A plurality of blade portions each having an outer peripheral side cut and raised at a predetermined position in the circumferential direction of the base portion and bent in the axial direction;
2. The centrifugal pump according to claim 1, further comprising: a cylindrical shaft portion protruding along the axial direction at a center portion of the base portion. The impeller is integrally formed of a resin material,
A base formed in a substantially disc shape;
A plurality of blade portions protruding along the axial direction at predetermined locations in the circumferential direction of the base portion, and
The centrifugal pump according to claim 1, further comprising: a columnar shaft portion extending in an axial direction from a central portion of an inner surface of the base portion. The centrifugal pump according to claim 3, wherein an insert is provided in a predetermined range of a tip portion of the shaft portion. The impeller and the drive shaft are connected to each other by fixing the outer peripheral surface of the shaft portion to an inner peripheral surface of one end portion of the drive shaft via a predetermined adhesive. Centrifugal pump. The outer shape of the tip portion of the shaft portion is formed in a non-circular cross section, and the inner periphery of one end portion of the drive shaft is configured to engage with the tip portion of the shaft portion. The centrifugal pump according to any one of the above. An engagement groove is formed on one of the inner peripheral surface of the one end portion of the drive shaft or the outer peripheral surface of the tip portion of the shaft portion, and an engagement protrusion that engages with the engagement groove is formed on the other.
The centrifugal pump according to any one of claims 2 to 5, wherein the impeller and the drive shaft are connected by engaging the engagement protrusion with the engagement groove.

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