JP2004116486A - Water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a rotational speed of a rotating shaft becomes greater than required by making it possible to enlarge an external diameter of an input rotator fully without bringing a mass increase of an input rotator greatly, and to reduce a load in durability applied on a bearing and a shaft seal. <P>SOLUTION: A cylindrical wall 7 is provided in a pump housing, and the rotating shaft 5 for connecting a pump impeller 6 and a pulley 9 is inserted in the cylindrical wall 7. A mechanical seal 8 is sandwiched between an inside perimeter of the cylindrical wall 7 and the rotating shaft 5, and a bearing 14 is sandwiched between an outside perimeter of the cylindrical wall 7 and the pulley 9. In such a water pump, a power input and a bearing fixed part of the pulley 9 are comprised of a major diameter cylindrical wall 10 and a minor diameter cylinder wall 11, and both the cylindrical walls 10 and 11 are connected with an end wall 12. The pulley 9 can be enlarged in the external diameter without increasing the whole wall thickness. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention of this application relates to a water pump used for supplying cooling water for an engine or the like.
[0002]
[Prior art]
In this type of water pump, an impeller housed in a pump housing is driven to rotate to perform a pumping operation, and the impeller is connected to an input rotating body such as a pulley via a rotating shaft passing through the pump housing. . The rotating shaft is supported by the pump housing via a bearing, and leakage of cooling water from around the shaft is prevented by a shaft seal such as a mechanical seal.
[0003]
In such a water pump, usually, a shaft seal and a bearing are arranged in series around a rotating shaft, so that water vapor leaked from the shaft seal directly enters the bearing, and the water vapor causes rust on the bearing. Easily.
[0004]
Therefore, conventionally, a water pump that can cope with this has been devised (for example, see Patent Document 1).
[0005]
In this water pump, while an input rotary body coaxially connected to a rotary shaft is formed in a substantially cylindrical shape, a cylindrical wall surrounding the outer circumferential side of the rotary shaft is provided on the pump housing side, and the outer circumferential surface of the cylindrical wall is provided. A bearing is interposed between the inner peripheral surface of the input rotating body and a shaft seal is interposed between the inner peripheral surface of the cylindrical wall and the rotating shaft, and further, the end of the rotating shaft is connected to the input rotating body. The structure has a structure in which an opening is provided on the flange wall to communicate with the outside.
[0006]
In the case of this water pump, since the bearing and the shaft seal are arranged in parallel on the outer peripheral side and the inner peripheral side with the cylindrical wall interposed therebetween, water vapor leaking from the shaft seal does not directly enter the bearing, but reaches the flange wall. It is discharged to the outside of the pump through the opening. Therefore, rust generation of the bearing portion due to infiltration of water vapor is prevented by this structure.
[0007]
[Patent Document 1]
JP-A-2002-89486
[Problems to be solved by the invention]
In the case of this conventional water pump, since the input rotary body is directly supported by the bearing, the size of the bearing is determined by the outer diameter of the rotating shaft and the shaft seal, the wall thickness of the cylindrical wall, and the like. The outer diameter and other sizes of the input rotating body must be determined according to the outer diameter. However, if the thickness of the input rotating body is made extremely thick in order to increase the outer diameter of the input rotating body, the mass of the input rotating body becomes large, which is likely to be adversely affected by inertia when the pump is operated, and the power source is It may cause unnecessary load.
[0009]
Therefore, in the related art, these facts cause hesitation to increase the outer diameter of the input rotating body, and the actual situation is that the outer diameter of the input rotating body cannot be sufficiently increased. For this reason, in the related art, since the outer diameter of the input rotating body cannot be made sufficiently large, the rotating speed of the rotating shaft increases, which adversely affects the durability of the bearing and the shaft seal.
[0010]
Therefore, the invention of this application is to reduce the load on the bearing and the shaft seal from the viewpoint of durability by enabling the outer diameter of the input rotating body to be sufficiently increased without causing a large increase in the mass of the input rotating body. The purpose of the present invention is to provide a water pump that can be used.
[0011]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, the invention of this application provides a power input portion to which power is directly input and a bearing fixing portion fixed to a bearing of the input rotary body, each having a large-diameter cylindrical wall. And a small-diameter cylindrical wall, and the large-diameter cylindrical wall and the small-diameter cylindrical wall are connected by an end wall extending in the radial direction.
[0012]
In the case of the present invention, the power input portion and the bearing fixing portion of the input rotary body are constituted by a large-diameter cylindrical wall and a small-diameter cylindrical wall, respectively, and the two cylindrical walls are connected by end walls. Without increasing, the outer diameter of the power input portion of the input rotating body can be set to be sufficiently large. Therefore, according to the present invention, since the rotation speed of the rotating shaft does not become faster than necessary, the load on the bearing and the shaft seal on the durable surface is reduced, and as a result, the durability of the bearing and the shaft seal is reduced. improves. In addition, since the mass of the input rotating body does not increase significantly, the operation of the pump is not adversely affected by the inertial force, and the load on the power source can be reduced. Further, since the large-diameter cylindrical wall constituting the power input portion has a cantilever structure, it is possible to absorb input vibrations by using this cantilever structure.
[0013]
The rotating shaft is formed in a closed-end cylindrical shape whose side facing the pump chamber is closed, and the opening edge of the rotating shaft is connected to the small-diameter cylindrical wall by a flange wall extending radially outward, It is preferable that the end wall is disposed on an end of the small-diameter cylindrical wall opposite to the flange wall. In this case, the rotary shaft and the entire input rotary body can be easily formed by pressing from a single plate because the rotary shaft and the input rotary body have a continuous shape with a substantially constant thickness from the large-diameter cylindrical wall of the input rotary body. .
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the invention of this application will be described with reference to the drawings.
[0015]
First, a first embodiment shown in FIGS. 1 to 3 will be described. The water pump according to this embodiment is disposed on the front of the engine block 1 and circulates cooling water in the engine block 1 by using the rotational force of a crankshaft (not shown) as a power source.
[0016]
In the water pump, as shown in FIG. 1, a pump housing is constituted by a recess 2 on the front surface of the engine block 1 and a cover plate 3 attached to the front surface of the recess 2, and a pump chamber is provided between the recess 2 and the cover plate 3. 4 are formed. A pump impeller 6 connected to a rotating shaft 5 is disposed in the pump chamber 4, and the water pump performs a pumping operation by the rotation of the pump impeller 6. The pump impeller 6 is formed from a metal plate by press molding, and the center of the pump impeller 6 is press-fitted and fixed to the tip of the rotating shaft 5.
[0017]
The outer peripheral edge of the cover plate 3 is bolted to the engine block 1, while a cylindrical wall 7 protruding toward the outside of the engine block 1 is formed at the center of the cover plate 3. The shaft 5 is inserted from the outside of the cover plate 3. The cylindrical wall 7 is formed in a step shape, and a well-known mechanical seal 8 as a shaft seal for preventing leakage of cooling water is interposed between the inner peripheral surface of the large-diameter portion 7a on the root side and the rotating shaft 5. Have been. The small diameter portion 7b on the distal end side of the cylindrical wall 7 will be described later in detail.
[0018]
The rotary shaft 5 is provided coaxially and integrally with a pulley 9 as an input rotary body, and the pulley 9 is linked to a crankshaft via a belt (not shown) outside the pump housing. Specifically, the pulley 9 is integrally formed by pressing with a rotating shaft 5 from a metal plate (for example, SP120 or SPCC), and a main body of the pulley 9 is a large-diameter cylinder serving as a power input unit. It comprises a wall 10, a small-diameter cylindrical wall 11 serving as a bearing fixing portion, and an end wall 12 connecting the ends of the cylindrical walls 10, 11. The large-diameter cylindrical wall 10 is disposed coaxially on the outer peripheral side of the small-diameter cylindrical wall 11, and has a substantially U-shaped half-section obtained by cutting the main body of the pulley 9 along the axial direction.
[0019]
Further, the rotating shaft 5 is formed in a bottomed cylindrical shape whose side facing the inside of the pump chamber 4 is closed, and a flange wall 13 extending radially outward is formed at an opening edge on the base side thereof. . The outer peripheral edge of the flange wall 13 is connected to the end of the main body of the pulley 9 opposite to the end wall 12 of the small-diameter cylindrical wall 11. Therefore, the half cross-sectional shape of the body of the rotary shaft 5 and the pulley 9 is substantially S-shaped, and the whole is formed to have a substantially constant thickness.
[0020]
Here, a belt for power transmission is hung on the outer peripheral surface of the large-diameter cylindrical wall 10, but a bearing 14 is provided between the inner peripheral surface of the small-diameter cylindrical wall 11 and the small-diameter portion 7 b of the cover plate-side cylindrical wall 7. Is interposed. The bearing 14 is formed by a well-known sealed ball bearing having a seal structure between the outer race and the inner race, and is fixed to the small-diameter cylindrical wall 11 and the cover-plate-side cylindrical wall 7 by press-fitting. . The inner race of the bearing 14 abuts against a step between the small-diameter portion 7b and the large-diameter portion 7a of the cylindrical wall 7, and is thereby positioned on the cover plate 3 side.
[0021]
A plurality of openings 15 for discharging water vapor are formed in the flange wall 13 connecting the rotary shaft 5 and the small-diameter cylindrical wall 11 along the circumferential direction.
[0022]
Since the water pump is configured as described above, when the power of the crankshaft is input to the large-diameter cylindrical wall 10 of the pulley 9, the power is transmitted to the pump impeller 6 via the rotary shaft 5, and at this time, The rotation of the pump impeller 6 causes the cooling water to circulate in the engine block 1. At this time, the rotating shaft 5 and the pulley 9 are rotatably supported on the outer peripheral surface of the cylindrical wall 7 via the bearing 14, and leakage of the cooling water from around the rotating shaft 5 is prevented by the mechanical movement on the inner peripheral side of the cylindrical wall 7. Blocked by seal 8. Then, the water vapor of the cooling water that has passed through the mechanical seal 8 is discharged to the outside of the pump through the opening 15 of the flange wall 13. Therefore, steam does not directly enter the inside of the bearing 14 disposed on the outer peripheral side of the cylindrical wall 7, and rust is prevented from being generated in the bearing 14 due to infiltration of steam.
[0023]
In the case of this water pump, a pulley 9 serving as an input rotary member is provided with a large-diameter cylindrical wall 10 serving as a power input portion on the outer peripheral side of a small-diameter cylindrical wall 11 serving as a bearing fixing portion. Are connected by the end wall 12, so that the outer diameter of the power input portion can be sufficiently increased without increasing the thickness of the entire pulley 9 by increasing the diameter of the end wall 12 at the time of design. be able to. Therefore, the rotation speed of the rotating shaft 5 during normal operation is set to a speed range advantageous for the durability of the bearing 14 and the mechanical seal 8 without increasing the inertia force or the power load due to the increase in the mass of the pulley 9. can do.
[0024]
Further, in the case of this water pump, since the large-diameter cylindrical wall 10 of the pulley 9 is connected to the small-diameter cylindrical wall 11 via the end wall 12 at one end in the axial direction, the large-diameter cylindrical wall 10 is connected via a belt. Is supported by the bearing 14 through the cantilever structure. For this reason, the vibration input to the pulley 9 through the belt is absorbed by the cantilever structure, and the problem that the vibration adversely affects the bearing 14 can be eliminated.
[0025]
Further, as in the water pump of this embodiment, the rotating shaft 5 is formed in a cylindrical shape with a bottom, and the opening edge of the rotating shaft 5 is connected to the small-diameter cylindrical wall 11 of the pulley 9 by a flange wall 13 to rotate the rotating shaft 5. When a half cross section from the shaft 5 to the pulley 9 is formed into an S-shape having a substantially constant thickness, the portion from the pulley 9 to the rotary shaft 5 can be easily formed from a single plate by press molding. Therefore, parts integrated from the pulley 9 to the rotary shaft 5 can be efficiently produced, and the manufacturing cost of the pump can be reliably reduced.
[0026]
Subsequently, a second embodiment shown in FIGS. 4 to 6 will be described. Since the basic configuration of this embodiment is almost the same as that of the first embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and the following description will be made of the parts different from the first embodiment. Will be mainly described.
[0027]
In the water pump of this embodiment, the portion from the pulley 109, which is a power input portion, to the rotary shaft 105 is integrally formed of a resin such as PPS. The rotary shaft 105 is formed solid, and the large-diameter cylindrical wall 10 and the small-diameter The end wall 112 connecting the cylindrical wall 11 is formed continuously on the same side as the flange wall 13 connecting the rotary shaft 105 and the small-diameter cylindrical wall 11.
[0028]
Also in the case of this embodiment, the bearing 14 is interposed between the inner peripheral surface of the small-diameter cylindrical wall 11 of the pulley 109 and the cylindrical wall 7 on the cover plate 3 side. Is provided between the inner peripheral surface and the rotating shaft 105, and the flange wall 13 is provided with an opening 15 for allowing water vapor to escape.
[0029]
Therefore, also in the case of this embodiment, the outer diameter of the pulley 109 can be set to be sufficiently large without increasing the mass while exhibiting the basic effect of preventing the entry of water vapor into the bearing 14. However, when the portion from the pulley 109 to the rotating shaft 105 is formed of a resin as in this embodiment, the degree of freedom in design is greatly increased, and it is advantageous in terms of cost for mass production.
[0030]
The embodiment of the invention of this application is not limited to those described above.For example, when the pulley and the rotating shaft are formed of metal, they may be formed by injection molding instead of press molding, Further, the input rotary body is not limited to the pulley on which the belt is hung, but may be a sprocket or the like with which a chain is engaged.
[0031]
Next, inventions other than those described in the claims that can be understood from the above embodiments will be described below together with their operational effects.
[0032]
3. The water pump according to claim 2, wherein the rotating shaft and the pulley are formed integrally by press molding.
[0033]
In this case, it is possible to easily integrally form the portion from the pulley to the rotating shaft.
[0034]
(B) The wall connecting the rotary shaft and the small-diameter cylindrical wall is provided with an opening for allowing water vapor leaked from the shaft seal to escape to the outside. The water pump described in Crab.
[0035]
In this case, it is possible to eliminate the problem that the steam leaking from the shaft seal goes around the bearing and the steam generates rust on the bearing.
[Brief description of the drawings]
FIG. 1 is a sectional view taken along the line AA of FIG. 2 showing a first embodiment of the present invention;
FIG. 2 is a front view showing the same embodiment.
FIG. 3 is a perspective view showing the same embodiment.
FIG. 4 is a sectional view taken along the line BB of FIG. 5 showing a second embodiment of the present invention;
FIG. 5 is a front view showing the same embodiment.
FIG. 6 is a perspective view showing the same embodiment.
[Explanation of symbols]
2 ... recess (pump housing)
3 ... Cover plate (pump housing)
4 pump chamber 5, 105 rotating shaft 6 pump impeller 7 cylindrical wall 8 mechanical seal (shaft seal)
9,109 ... pulley (input rotating body)
10 large-diameter cylindrical wall 11 small-diameter cylindrical wall 12, 112 end wall 13 flange wall 14 bearing

Claims (2)

A pump housing forming a pump chamber, a pump impeller housed in the pump housing to perform a pumping operation, and a substantially cylindrical input rotator disposed outside the pump housing and rotated by receiving power from a drive source A rotary shaft that is provided integrally and coaxially with the input rotary body and transmits rotation of the input rotary body to the impeller; and a cylinder that is provided integrally with the pump housing and surrounds an outer peripheral side of the rotary shaft. A wall, a bearing interposed between the outer peripheral surface of the cylindrical wall and the inner peripheral surface of the input rotating body, and rotatably supporting the input rotating body on the cylindrical wall; and a bearing for rotating the inner peripheral surface of the cylindrical wall. A shaft seal interposed between the shafts and preventing leakage of cooling water from around the rotation shaft;
Of the input rotary body, a power input portion to which power is directly input, and a bearing fixing portion fixed to the bearing are respectively constituted by a large-diameter cylindrical wall and a small-diameter cylindrical wall, and the large-diameter cylindrical wall and the small-diameter cylindrical wall are respectively provided. A water pump in which cylindrical walls are connected by end walls extending in a radial direction. The rotary shaft is formed in a closed-end cylindrical shape whose side facing the pump chamber is closed, and an opening edge of the rotary shaft is connected to the small-diameter cylindrical wall by a flange wall extending radially outward, The water pump according to claim 1, wherein the end wall is disposed on an end of a small-diameter cylindrical wall opposite to the flange wall.

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