WO2016006357A1

WO2016006357A1 - Water pump and assembly method for water pump

Info

Publication number: WO2016006357A1
Application number: PCT/JP2015/065359
Authority: WO
Inventors: 雄介古澤
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2014-07-09
Filing date: 2015-05-28
Publication date: 2016-01-14
Also published as: CN106471255A; US20170114792A1; JP6188942B2; JPWO2016006357A1; DE112015003163T5

Abstract

The present invention comprises a drive shaft (7) formed from a synthetic resin material, a pulley (5) provided to be integrally rotatable with a large diameter shaft portion (7a) side of the drive shaft, and an impeller (8) formed from a synthetic resin material and fitted astride an intermediate shaft portion (7b) and small diameter shaft portion (7c) by means of a fitting hole (23), wherein first and second step portions (22, 24) that delimit the maximum fitting position of the impeller in the axial direction are provided between the other end of the drive shaft and the fitting hole, a pushnut (25) that, in concert with the first and second step portions, restricts the movement of the impeller (8) in the axial direction at the maximum fitting position is provided to a projection (7d) on the impeller front surface side of the drive shaft, the cross section of a fitting part (20) of the intermediate shaft portion is cocoon-shaped, and the cross section of a large diameter fitting aperture portion (23a) is the same cocoon shape as the fitting part (20). Consequently, the coupling force between the impeller and the drive shaft is improved and it is possible to restrict the slipping of the impeller with respect to the drive shaft and disengagement from the drive shaft.

Description

Water pump and method of assembling the water pump

The present invention relates to a water pump which is applied to, for example, an engine cooling system of a motor vehicle and is provided to circulate cooling water in the cooling system, and a method of assembling the water pump.

As a conventional water pump of this type, one described in Patent Document 1 below is known.

Generally described, this water pump includes a pump housing having a pump chamber therein, a cylindrical drive shaft formed of a synthetic resin material, and rotatably supported in the pump chamber, and one end of the drive shaft. A pulley made of synthetic resin integrally connected via a flange wall and rotated by external power transfer, and a ball bearing provided on the inner peripheral side of the pulley via a cylindrical metal insert, A synthetic resin impeller provided at the other end of the drive shaft; and a mechanical seal interposed between the pump housing and the drive shaft to seal between the pump chamber and the ball bearing And.

The impeller and the drive shaft are the vibration of the inner peripheral surface of the insertion hole formed in a substantially circular shape in a horizontal cross section at the central position of the impeller and the outer peripheral surface of the other end of the drive shaft inserted in the insertion hole. It is integrally rotatably coupled by welding.

Japanese Patent Application Publication No. 2002-349481

However, although the impeller and the drive shaft are integrally rotatably coupled by vibration welding as described above, when the vibration welding is insufficient, the bonding strength of the welding surface is reduced. When the cooling water is pumped, the connection is separated, which may cause slippage or slippage between the impeller and the drive shaft.

The present invention has been made in view of the circumstances of the conventional water pump, and provides a water pump that can control slippage of the impeller relative to the drive shaft and dropout from the drive shaft.

According to the present invention, a drive shaft is disposed in a pump housing and is formed by a synthetic resin material, and a pulley rotatably provided integrally with one end of the drive shaft and transmitting power from a drive source to rotate the drive shaft; An impeller formed of a synthetic resin material and fitted to the other end of the drive shaft through a fitting hole, and the impeller is interposed between the other end of the drive shaft and the fitting hole of the impeller A restricting portion is provided which restricts the axial maximum engagement position of the impeller, and the axial movement of the impeller in the maximum engagement position cooperates with the restriction portion on the tip end side of the other end of the drive shaft Of the other end of the drive shaft and the cross-sectional shape of the portion fitted to the impeller as a rotation restricting portion, and the cross-sectional shape of the fitting hole is the other end It was formed as a rotation regulation part as well as the part of It is characterized.

According to the present invention, the coupling force between the impeller and the drive shaft can be improved, and slippage of the impeller relative to the drive shaft and detachment from the drive shaft can be restricted.

It is a longitudinal cross-sectional view of the water pump in the 1st Embodiment of this invention. It is an exploded perspective view of a water pump in a 1st embodiment. It is an A arrow line view of FIG. (A) is an enlarged perspective view of a drive shaft provided in the first embodiment, and (B) is a sectional view taken along the line AA of (A). (A) is a perspective view which shows and shows the principal part of 1st Embodiment, (B) is an enlarged view of (A). It is a rear perspective view of an impeller provided to a 1st embodiment. It is a disassembled perspective view which shows the operation process at the time of assembling | attaching the impeller provided to 1st Embodiment to a drive shaft. It is a perspective view which partially shows in cross section the state where the impeller provided to a 1st embodiment was attached to a drive shaft. (A) is an enlarged perspective view of a drive shaft provided in a second embodiment of the present invention, and (B) is a cross-sectional view taken along the line BB of (A). (A) is an enlarged perspective view of a drive shaft provided in a third embodiment of the present invention, and (B) is a cross-sectional view taken along the line CC of (A). (A) is an enlarged perspective view of a drive shaft provided in a fourth embodiment of the present invention, and (B) is a cross-sectional view taken along the line DD of (A). (A) is an enlarged perspective view of a drive shaft provided in a fifth embodiment of the present invention, and (B) is a cross-sectional view taken along the line EE of (A).

First Embodiment
Hereinafter, each embodiment of a water pump concerning the present invention is explained in full detail based on a drawing. The water pump 1 is applied to a cooling device for circulating antifreeze liquid (ethylene glycol), which is cooling water, between a radiator of an automobile and an internal combustion engine.

As shown in FIGS. 1 and 2, the water pump 1 is directly attached by bolting or the like to the side of a cylinder block of an internal combustion engine (not shown) and has a pump housing 3 having a pump chamber 3 in the front end on the cylinder block side. 2, a pulley 5 rotatably supported by a single ball bearing 4 as a bearing on the front end side of the pump housing 2, and a metal insert interposed between the pulley 5 and the ball bearing 4 6 and a drive shaft 7 which is disposed through the inside of the pump housing 2 and has one end side integrally formed with the pulley 5 and is fixed to the other end side of the drive shaft 7 so as to be rotatable in the pump chamber 3 And a mechanical shaft that is interposed between the pump housing 2 and the drive shaft 7 to seal between the pump chamber 3 and the ball bearing 4. A seal 9, which is mainly comprised.

The pump housing 2 is integrally formed of an aluminum alloy material, and the housing body 10 on the side of the pump chamber 3 is formed in a deformed annular ring, and a cylindrical portion with a step diameter on the rear end side of the housing body 10 It has 11 in one.

The housing body 10 is provided at its front end with a flat annular mounting surface 10a that abuts on a flat portion of the side of the cylinder block, and a mounting bolt screwed to the cylinder block is inserted around the outer periphery. A plurality of bosses 10c in which the bolt holes 10b are formed are provided in a projecting manner.

Further, inside the housing main body 10, there is a discharge port 10d for discharging the cooling water flowing into the pump chamber 3 from the suction port on the radiator side (not shown) into the water jacket in the cylinder block as the impeller 8 rotates. It is formed.

As shown in FIGS. 1 to 3, the cylindrical portion 11 has a large diameter cylindrical portion 11a on the side of the pump chamber 3, and a medium diameter cylindrical portion 11b extending in the direction of the ball bearing 4 from the large diameter cylindrical portion 11a. And a small diameter cylindrical portion 11c extending from the middle diameter cylindrical portion 11b to one end side of the drive shaft 7.

The middle diameter cylindrical portion 11 b is vertically formed with a drain hole 12 through which water droplets of cooling water leaked from the mechanical seal 9 flow downward on the lower side in the direction of gravity. A drain chamber 13 for collecting and storing water droplets dropped from the drain hole 12 is formed across the inside of the large diameter cylindrical portion 11a. A lower end opening of the drain chamber 13 is sealed in a liquid tight manner by a drain cap 14.

The ball bearing 4 is general, and as shown in FIG. 1 and FIG. 2, the inner ring 4a press-fitted into the small diameter cylindrical portion 11c, the outer ring 4b press-fitted into the insert 6, and the inner ring A plurality of balls 4c are provided so as to be rollable between a ring 4a and an outer ring 4b via a cage.

The maximum press-fit position of the inner ring 4 a in the axial direction is regulated by the front end face of the medium-diameter cylindrical portion 11 b of the cylindrical portion 11. On the other hand, the axial position of the outer ring 4 b is set in advance by the press-fit length into the insert 6.

As shown in FIGS. 1 and 2, a pair of first and

second seal members

15 and 16 are provided at the axial direction front and rear ends of the ball bearing 4 for preventing intrusion of dust etc. into the ball bearing 4. The two

seal members

15 and 16 are formed in a substantially annular shape, and are disposed to face each other in the axial direction of the ball bearing 4.

The first seal member 15 is fixed in a sandwiched state between the middle diameter cylindrical portion 11b and one end surface of the inner ring 4a. On the other hand, the second seal member 16 is fixed in a sandwiched state between the second seal member 16 and the other end surface of the inner ring 4a by a retainer 17 which is a holding member.

The pulley 5 is integrally formed with the drive shaft 7 by a synthetic resin material containing a glass fiber 26 described later, as shown in FIGS. 1 and 2, from the one end side of the drive shaft 7 in the radial direction. A flange wall 5a which is a disk-shaped end wall extending, a large diameter cylindrical base 5b bent in the axial direction of the drive shaft 7 from the outer peripheral edge of the flange wall 5a, and the cylindrical base 5b The belt mounting portion 5c is provided to project from the outer peripheral surface.

As shown in FIGS. 1 and 2, in the flange wall 5a, six through holes 18 for inserting a jig at the time of assembly are axially formed at substantially equally spaced positions in the circumferential direction. The reinforcing rib 19 is integrally provided on the outer surface along the radial direction from the central position.

As shown in FIG. 1, the cylindrical base 5 b is provided with the metal cylindrical insert 6 on the inner peripheral side. The insert 6 comprises a cylindrical main body 6a and a flange portion 6b integrally formed at the end of the main body 6a, and the flange portion 6b is embedded in the cylindrical base portion 5b at the time of resin molding of the pulley 5 Fixed.

The belt mounting portion 5c is configured such that a rotational force is transmitted to the outer periphery formed in the shape of a corrugated tooth by a transmission belt wound around a drive pulley fixed to the tip end portion of a crankshaft not shown. .

As shown in FIG. 1, the drive shaft 7 is formed in a cylindrical shape and a step shape by a synthetic resin material into which glass fibers 26 described later are compounded, and is integrally integrated with the center of the flange wall 5 a of the pulley 5 from the axial direction. A large diameter shaft portion 7a which is one end coupled to the middle diameter shaft portion 7b which is the other end portion axially extended from the other end edge of the large diameter shaft portion 7a, and the middle diameter shaft portion It is comprised from the small diameter axial part 7c which is the other end similarly extended axially from the other end edge of 7b.

Further, the drive shaft 7 has a tapered shape in which the diameter gradually decreases from the large diameter shaft portion 7a to the tip of the small diameter shaft portion 7c, that is, the rigidity of the large diameter shaft portion 7a which is a connecting portion with the pulley 5 is secured. It is formed in a shape that takes into consideration the draft when drawing out from the mold after injection molding.

As shown in FIGS. 1 and 8, the impeller 8 is fitted to the medium diameter shaft portion 7 b so as to straddle the small diameter shaft portion 7 c via a fitting hole 23 described later. A part of the middle diameter shaft portion 7b (fitting portion 20), which is a fitting range with the fitting hole 23, has a cross section as a rotation restricting portion that restricts the relative rotation of the impeller 8 with respect to the drive shaft 7. It is formed in the non-perfect circle shape.

Specifically, as shown in FIGS. 4A and 4B, the fitting portion 20 of the outer peripheral surface from the substantially central position in the axial direction of the medium diameter shaft portion 7b to the end edge on the small diameter shaft portion 7c side. A pair of recesses 21 is formed at a position of 180 ° in the circumferential direction. The outer circumferential surface of each of the recesses 21 is formed as a curved surface, and the circumferential side edges thereof are connected to the outer circumferential surface of the middle diameter shaft portion 7 b with a gentle curved surface.

As a result, the fitting portion 20 of the middle diameter shaft portion 7b, which is a fitting range with the fitting hole 23, has a non-perfect circle shape having a cross-sectional shape that is point-symmetrical and has a smooth uneven shape. It has a shape.

The small diameter shaft portion 7c has a role as a guide portion when the impeller 8 is assembled, and the tip end portion is formed to project from the front end side of the impeller 8 and the protruding portion 7d is formed. A tapered surface 7e is formed at the tip end edge.

Further, an annular first step 22 that constitutes a part of the restricting portion is formed so as to be orthogonal to the axial direction at the connection point between the medium diameter shaft 7b and the small diameter shaft 7c. .

The impeller 8 is integrally formed of a synthetic resin material and, as shown in FIG. 1 to FIG. 3 and FIG. 6, has a substantially disc-like base 8a and a central portion of the base 8a It is comprised from the axial part 8b and the eight blade parts 8c radially formed from the outer peripheral surface of the axial part 8b in the front side of the said base 8a.

The base 8a is formed to a predetermined thickness and rotates with a gap on the back of the pump chamber 3, and as shown in FIG. 2, FIG. 3 and FIG. A pair of small diameter through holes 8d are bored at approximately the middle position, and the mechanical seal 9 is cooled by flowing cooling water to the back surface of the base 8a through the small diameter through

holes

8d, 8d. The seizure due to the sliding friction between the mechanical seal 9 and the drive shaft 7 is suppressed.

A fitting hole 23 into which the other end of the drive shaft 7 is fitted is formed in a penetrating manner in the inner axial direction of the shaft portion 8b, and the fitting hole 23 is fitted to the drive shaft 7 A position corresponding to the fitting portion 20 of the medium diameter shaft portion 7b is formed in the large diameter fitting hole portion 23a as a rotation restricting portion having a cross sectional shape substantially the same as the cross sectional shape of the fitting portion 20 There is.

That is, while the fitting portion 20 of the medium diameter shaft portion 7b is formed on the shaft portion with a cross section wedge shape, the inner peripheral surface shape of the large diameter fitting hole portion 23a is formed in the same cross section wedge shape Thus, the impeller 8 is fitted across the medium diameter shaft 7 b and the small diameter shaft 7 c of the drive shaft 7. The small diameter fitting hole 23b through which the small diameter shaft portion 7c of the fitting hole 23 is inserted is formed in a cylindrical shape following the outer peripheral surface shape of the small diameter shaft portion 7c.

The large diameter fitting hole portion 23a is formed to have a slightly larger diameter and a uniform inner diameter with respect to the maximum diameter of the fitting portion 20 having a downward tapered shape toward the tip end side of the drive shaft 7 The small diameter fitting hole 23b is formed to have a slightly larger diameter and a uniform inner diameter with respect to the maximum diameter of the small diameter shaft portion 7c, and the impeller 8 and the drive shaft 7 are separated It is designed to be mated.

Further, between the large diameter fitting hole portion 23a and the small diameter fitting hole portion 23b of the fitting hole 23, an annular second step portion 24 which constitutes a part of the regulating portion is formed. .

The second step portion 24 is formed to be orthogonal to the axial direction, and when the impeller 8 is inserted into the drive shaft 7, the drive formed to be orthogonal to the axial direction as well. It abuts on the first step portion 22 on the side of the shaft 7 so that the axial movement on the side of the large diameter shaft portion 7a beyond that is restricted.

Therefore, the impeller 8 is determined by the first stepped portion 22 and the second stepped portion 24 to determine the maximum fitting position with respect to the drive shaft 7, and the axial movement from here to the large diameter shaft portion 7a is performed. It is supposed to be regulated.

Further, when the impeller 8 is assembled to the drive shaft 7, as described above, the small diameter shaft portion 7c is formed to project from the front surface side of the impeller 8, but it is fixed to the projecting portion 7d. A metal push nut 25 which is a member is engaged.

As shown in FIGS. 1 and 2, the push nut 25 is formed in a thin disc shape, and an insertion hole 25a smaller in diameter than the small diameter shaft portion 7c of the drive shaft 7 is formed at the center position. It is done.

Further, a plurality of claws 25c are formed on the push nut 25 via a plurality of cut-outs 25b cut out in the direction of the insertion hole 25a from the outer peripheral part, and the push nut 25 is disposed at the maximum push-in position. It fixes by making each tip edge of each nail | claw part 25c bite in the outer peripheral surface of the said protrusion part 7d in line contact or point contact form. As a result, the movement of the impeller 8 in the axial direction to the side opposite to the

step portions

22 and 24 is restricted.

The mechanical seal 9 is a general one as shown in FIG. 1 and FIG. 2, and the cartridge portion 9 a is fixed to the inner peripheral surface of the medium diameter cylindrical portion 11 b of the cylindrical portion 11; A sleeve portion 9b supported on the outer peripheral surface of the medium diameter shaft portion 7b of the shaft 7, and a seal portion 9c provided between the inner peripheral side of the cartridge portion 9a and the outer peripheral side of the sleeve portion 9b It consists of

In addition, although the said pulley 5 and the drive shaft 7 are integrally resin-molded by the metal mold | die as mentioned above, the synthetic resin material with which the short glass fiber 26 was mix | blended is used in the case of the shaping | molding.

This synthetic resin material is injected from a position corresponding to the end face of the small diameter shaft 7c of the drive shaft 7 of the mold, and is axially inserted into the flange wall 5a of the pulley 5 of the large diameter shaft 7a. When it flows to the coupled position, it flows radially to the position of the outer peripheral edge of the belt mounting portion 5c of the pulley 5 in this radial direction, whereby the entire mold is filled.

At this time, the glass fiber 26 is oriented in the flow direction of the synthetic resin material in the vicinity of the portion which was in contact with the mold at the time of resin molding, that is, in the vicinity of the outer peripheral surface of the pulley 5 and the drive shaft 7 In the medium diameter shaft portion 7b of the drive shaft 7 shown in FIGS. 5 (A) and 5 (B), the glass fiber 26a inside is oriented along the circumferential direction, whereas the glass near the outer peripheral surface is The fibers 26b are oriented along the axial direction (see the arrow in FIG. 5 (B)).
[Assembling method of impeller and drive shaft]
Hereinafter, a method of assembling the impeller 8 to the drive shaft 7 will be described.

First, by relatively rotating the impeller 8 with respect to the drive shaft 7, the fitting portion 20 of the drive shaft 7 and the large diameter fitting hole 23a of the impeller 8 are aligned in advance.

Next, as shown in FIG. 7, the impeller 8 is moved from the tip end side of the small diameter shaft portion 7c of the drive shaft 7 along the axial direction while being fitted to the large diameter shaft portion 7a side. The first step 22 on the seventh side and the second step 24 on the impeller 8 abut against each other (a maximum fitting position). At this time, while the impeller 8 is rotated with respect to the drive shaft 7, the impeller 8 is further pushed toward the large diameter shaft portion 7a, and it is confirmed whether the fitting between the fitting portion 20 and the large diameter fitting hole 23a is secure. .

Thereafter, the push nut 25 is engaged with each of the claws 25c at the projecting portion 7d of the small diameter shaft 7c which protrudes from the front side of the shaft 8b of the impeller 8 while maintaining the impeller 8 in the maximum fitting position. Is inserted while being elastically deformed in the radial direction, and pushed into the front end surface position of the shaft portion 8b of the protruding portion 7d.

As a result, the push nut 25 is engaged with the outer peripheral surface of the projecting portion 7d while the claws 25c are elastically deformed in the radial direction. Then, the tip end edge of each claw 25c bites into the outer peripheral surface of the projecting portion 7d by elastic force (restoration force) in the diameter reducing direction, so that the push nut 25 is fixed in axial position. ing.

By the above method, as shown in FIG. 8, the impeller 8 is fitted with a large diameter fitting portion of the impeller 8 with the fitting portion 20 of the medium diameter shaft portion 7b of the drive shaft 7 formed in a substantially wedge shape in cross section. The relative rotation is restricted by the foraminous part 23 a, and the axial movement is restricted by the restricting part consisting of the first and

second step parts

22 and 24 and the push nut 25. It is firmly assembled.
[Operation and effect of the first embodiment]
Therefore, according to this embodiment, when the crankshaft of the engine is rotationally driven and the pulley 5 is rotationally driven, the impeller 8 is rotated via the drive shaft 7 integrally formed with the pulley 5. The pump action is performed, and cooling water is pumped from the discharge port 10d to the water jacket of the engine to cool the entire internal combustion engine.

At this time, between the drive shaft 7 and the impeller 8, the drive shaft by the moment force (force in the circumferential direction) accompanying the transmission of the rotational force and the reaction force when each blade portion 8 c pumps cooling water. An axial load (axial force) acts in the direction of the tip end of 7, but when the coupling strength between the drive shaft 7 and the impeller 8 is low, the exchange of rotational force becomes insufficient and the impeller 8 becomes the drive shaft 7 On the other hand, there has been a possibility that a problem such as idling may occur or the impeller 8 may come off from the drive shaft 7 without being able to withstand the axial load.

On the other hand, in the present embodiment, the impeller is formed by fitting the fitting portion 20 of the medium diameter shaft portion 7b formed in substantially the same cross section wedge shape with the large diameter fitting hole portion 23a of the impeller 8 The relative rotation with respect to the drive shaft 7 was restricted to improve the coupling strength to the force in the rotational direction, that is, the rotation stopping force.

That is, when the drive shaft 7 is rotated with the rotation of the pulley 5, the relative rotation is restricted by the engagement between the fitting portion 20 and the large diameter fitting hole portion 23a, and the rotational force to the impeller 8 is reliably achieved. To communicate.

Further, in the present embodiment, since the movement of the impeller 8 in the front-rear axial direction is surely restricted by the cooperation of the first and

second step parts

22 and 24 and the push nut 25, the bonding strength is further improved.

That is, even if axial load along the axial direction to the tip end side of the drive shaft 7 is applied to the impeller 8, the tip edge of each claw 25 c provided on the inner peripheral side of the push nut 25 has a small diameter shaft by elastic force. Since it bites into the outer peripheral surface of 7 c and is firmly engaged, the movement of the impeller 8 is strongly restricted.

Therefore, according to the present embodiment, since the coupling strength between the drive shaft 7 and the impeller 8 is improved, the idle rotation of the impeller 8 with respect to the drive shaft 7 and the dropout from the drive shaft 7 can be reliably suppressed. .

Further, in the present embodiment, since the push nut 25 is made of metal and the drive shaft 7 is made of synthetic resin, the small diameter shaft portion 7c is in contact with the tip edge of each claw 25c of the push nut 25. It is necessary to take into consideration the possibility that the part is corroded by resin creep (aging deterioration), the push nut 25 is detached from the drive shaft 7, and the connection between the drive shaft 7 and the impeller 8 is released.

For this reason, in the present embodiment, the push nut 25 and the small diameter shaft portion are formed by using the push nut 25 which is formed in a thin disk shape and is fixed in line contact or point contact with the small diameter shaft portion 7c. The contact range with 7c was made very small. That is, even if the resin creep occurs on the contact surface of the small diameter shaft portion 7c with the push nut 25 and the push nut 25 moves to the tip end side of the drive shaft 7, the range is extremely narrow. Can be reduced to maintain the connection between the drive shaft 7 and the impeller 8.

Further, the small diameter shaft portion 7c of the drive shaft 7 is formed to project from the front end side of the impeller 8, and the push nut 25 is positioned at the front end surface of the shaft portion 8b of the impeller 8 at the projecting portion 7d. Therefore, even if the resin creep occurs and the push nut 25 moves to the tip side of the small diameter shaft portion 7c, it is bitten into the moved end and fixed again, and the drive shaft 7 and the impeller 8 and Connection is maintained.

Further, in the present embodiment, since the cross-sectional shape (wedge shape) of the fitting portion 20 is formed into a smooth uneven shape having no corner portion (edge), stress compared to a shape having a corner portion Concentration is less likely to occur.

Furthermore, since the cross-sectional shape of the fitting portion 20 is also point-symmetrical, stress concentration is unlikely to occur regardless of the rotational direction, and, for example, it flows by inertia immediately after the operation of the water pump 1 is stopped. Even in the case of receiving a rotational force in a direction reverse to the normal direction from the cooling water, stress concentration is less likely to occur in the fitting portion 20.

Thus, since the fitting portion 20 is formed in a shape that avoids stress concentration, it is possible to effectively suppress the deformation, breakage or the like of the drive shaft 7 (the fitting portion 20).

Further, in the present embodiment, the glass fiber 26 is contained in the inside of the drive shaft 7, but the glass fiber 26 has an effect of improving the rigidity against the force orthogonal to the oriented direction. There is. That is, since the glass fibers 26b in the vicinity of the outer peripheral surface of the drive shaft 7 are oriented along the axial direction, the rigidity (torsional rigidity) with respect to the rotation direction which is the orthogonal direction is improved.

In particular, in the present embodiment, since the outer peripheral surface of the fitting portion 20 is all formed by a curved surface and the surface area is larger than the shape including the linear portion, the glass oriented in the direction orthogonal to the rotation direction Since the proportion of the fibers 26 b is increased, the torsional rigidity of the fitting portion 20 is further improved.

Therefore, deformation, breakage or the like of the drive shaft 7 (fitting portion 20) can be more effectively suppressed.

Furthermore, in the present embodiment, since the assembly of the impeller 8 to the drive shaft 7 is entirely performed in the axial direction, the assembling workability is improved and the tip of the drive shaft 7 is stronger in the radial direction. Since no load is applied, the assembly operation can be performed without deforming the drive shaft 7.

Further, since the connection between the drive shaft 7 and the impeller 8 can be released only by removing the push nut 25, the workability for disassembling can be improved as compared with a connection method such as press-fitting or welding.
Second and third embodiments
FIG. 9 shows the second embodiment, and the basic configuration is the same as that of the first embodiment, but the fitting portion 20 of the medium diameter shaft portion 7b of the drive shaft 7 and the large diameter fitting hole of the impeller 8 The difference is that 23a is formed in a substantially elliptical shape in cross section.

FIG. 10 shows the third embodiment, and the basic configuration is the same as that of the first embodiment, but the fitting portion 20 of the medium diameter shaft portion 7b of the drive shaft 7 and the large diameter fitting hole of the impeller 8 The difference is that the cross section 23a is formed in a substantially oval shape in cross section.

As in the first embodiment, these are also shaped so as not to have corners (edges) on the outer peripheral surface of the fitting portion 20, so local stress concentration inside the fitting portion 20 can be achieved. It can be relaxed.
Fourth and fifth embodiments
11 and 12 show the fourth and fifth embodiments of the present invention, in which the fitting portion 20 of the medium diameter shaft portion 7b of the drive shaft 7 and the large diameter fitting hole portion 23a of the impeller 8 are cross sections. It is formed in a polygonal shape.

In the fourth embodiment shown in FIG. 11, the fitting portion 20 and the large diameter fitting hole 23a are formed in a substantially hexagonal cross section.

In the fifth embodiment shown in FIG. 12, the fitting portion 20 and the large diameter fitting hole 23a are formed in a substantially rectangular shape in cross section.

Although these have a plurality of corner portions 27 (edges) on the outer peripheral surface of the fitting portion 20, stress concentration is likely to occur in the vicinity of the corner portions 27 as compared with the first embodiment and the like. Since the corner portions 27 firmly engage with the inner peripheral surface of the large diameter fitting hole portion 23a, the idle rotation of the impeller 8 with respect to the drive shaft 7 can be further suppressed (FIG. 11 (B), FIG. 12 (B )reference). Each corner 27 is rounded to avoid excessive stress concentration.

The present invention is not limited to the configuration of each of the above-described embodiments, and the configuration can be changed without departing from the scope of the invention.

For example, in each of the embodiments, the drive shaft 7 and the pulley 5 are described as being integrally formed, but they may be separately formed.

In each of the above embodiments, the first and

second step portions

22 and 24 are used as the restricting portions for restricting the maximum fitting position of the impeller 8 with respect to the drive shaft 7. However, the restricting portions are limited to the step portions. It is not something that can be done.

Furthermore, although the said push nut 25 was used as a fixing member in said each embodiment, a fixing member is not restricted to this, For example, it is also possible to apply a snap ring.

Claims

A drive shaft disposed in the pump housing and formed of a synthetic resin material;
A pulley which is integrally rotatably provided at one end of the drive shaft and receives power from the drive source to rotate;
An impeller formed of a synthetic resin material and fitted to the other end of the drive shaft through a fitting hole;
Equipped with
Between the other end of the drive shaft and the fitting hole of the impeller, there is provided a regulating portion for regulating the maximum fitting position in the axial direction of the impeller, and at the other end tip end side of the drive shaft, A fixing member for restricting axial movement of the impeller in the maximum fitting position in cooperation with the restricting portion is provided, and a cross section of a portion of the other end of the drive shaft to be fitted to the impeller is rotated. A water pump characterized in that it is formed as a restricting portion, and the cross-sectional shape of the fitting hole is formed as a rotation restricting portion like the portion of the other end of the drive shaft.
In the water pump according to claim 1,
The cross-sectional shape of the portion of the other end of the drive shaft to be fitted to the impeller is formed to have no corner, and the cross-sectional shape of the fitting hole is the same as the portion of the other end of the drive shaft. A water pump characterized in that it has a cornerless shape.
In the water pump according to claim 2,
The cross-sectional shape of the fitting portion of the impeller at the other end of the drive shaft is formed to be a curved surface as a whole, and the cross-sectional shape of the fitting hole is a portion of the other end of the drive shaft The water pump is characterized in that it has a curved surface as a whole.
In the water pump according to claim 3,
The cross-sectional shape of the portion of the other end of the drive shaft to be fitted to the impeller is formed into a smooth uneven shape, and the cross-sectional shape of the fitting hole is as smooth as the portion of the other end of the drive shaft Water pump characterized in that it has an irregular shape.
In the water pump according to claim 4,
The water pump, wherein the synthetic resin material forming the drive shaft includes glass fibers, and the glass fibers are oriented along the axial direction on the outer surface of the drive shaft.
In the water pump according to claim 5,
The cross-sectional shape of the portion of the other end of the drive shaft to be fitted to the impeller is formed point-symmetrically, and the cross-sectional shape of the fitting hole is point-symmetrical similarly to the portion of the other end of the drive shaft A water pump characterized in that it has a shape.
In the water pump according to claim 3,
The cross-sectional shape of the portion of the other end of the drive shaft to be fitted to the impeller is formed in an elliptical shape, and the cross-sectional shape of the fitting hole is elliptical as in the region of the other end of the drive shaft A water pump characterized by being formed.
In the water pump according to claim 1,
The cross-sectional shape of the portion of the other end of the drive shaft to be fitted to the impeller is formed into a polygonal shape, and the cross-sectional shape of the fitting hole is also polygonal like the portion of the other end of the drive shaft A water pump characterized by being formed.
In the water pump according to claim 8,
The water pump characterized in that the polygonal shape is a hexagonal shape.
In the water pump according to claim 8,
The water pump characterized in that the polygonal shape is a square shape.
In the water pump according to claim 1,
The water pump, wherein the other end side of the drive shaft is protruded from the fixing member.
In the water pump according to claim 11,
The water pump, wherein the fixing member is fixed to an outer surface of the drive shaft by point contact or line contact.
In the water pump according to claim 12,
The water pump, wherein the fixing member is a retaining ring.
In the water pump according to claim 13,
The water pump, wherein the retaining ring is a push nut.
In the water pump according to claim 1,
The water pump, wherein the drive shaft is formed in a tapered shape that inclines upward to the pulley side.
A pump housing having a cylindrical portion at one end in the axial direction;
A drive shaft rotatably supported in the pump housing and formed of a synthetic resin material;
A synthetic resin having a disk-like end wall integrally fixed to one end of the drive shaft and a cylindrical base integrally coupled to an outer peripheral edge of the end wall so as to surround the cylindrical portion A pulley formed by the material,
A cylindrical metal member fixed to the inner periphery of the cylindrical base;
A bearing portion which is refurbished between the metal member and the tubular portion and rotatably bears the drive shaft;
An impeller formed of a synthetic resin material and fitted to the other end side of the drive shaft;
Equipped with
Between the other end of the drive shaft and the fitting hole of the impeller, there is provided a regulating portion for regulating the maximum fitting position in the axial direction of the impeller, and at the other end tip end side of the drive shaft, A fixing member for restricting axial movement of the impeller in the maximum fitting position in cooperation with the restricting portion is provided, and a cross section of a portion of the other end of the drive shaft to be fitted to the impeller is rotated. A water pump characterized in that it is formed as a restricting portion, and the cross-sectional shape of the fitting hole is formed as a rotation restricting portion like the portion of the other end of the drive shaft.
A drive shaft disposed in the pump housing and formed of a synthetic resin material;
A pulley which is integrally rotatably provided at one end of the drive shaft and receives power from the drive source to rotate;
An impeller formed of a synthetic resin material and fitted to the other end side of the drive shaft;
A hollow fixing member mounted on the other end side of the driving shaft relative to the impeller;
A method of assembling a water pump, comprising:
After the impeller is fitted along the axial direction from the tip on the other end side of the drive shaft, the movement to the pulley side is restricted by the restricting portion provided between the impeller and the drive shaft The first step of pushing to the position where
And a second step of fixing the fixing member in the front end position of the impeller of the drive shaft after fitting the fixing member along the axial direction from the tip end portion of the other end of the drive shaft projecting from the impeller ,
A method of assembling a water pump having:
In the water pump assembling method according to claim 17,
The method of assembling a water pump, wherein the fixing member is engaged and fixed from an axial tip end side of the other end of the drive shaft.
A method of assembling a water pump according to claim 18, wherein
The method of assembling a water pump according to claim 1, wherein the fixing member is engaged and fixed by causing a claw portion formed on an inner peripheral side to bite into the drive shaft.