JP2011085154A - Bearing for water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a water pump, inhibiting rollers and a roller cage from pushing out a seal member. <P>SOLUTION: The bearing 1 for the water pump includes an outer ring 3 press-fitted in a bearing installing tube 9 and formed with outer rolling faces 3a, 3b on the inner peripheral surface, rolling elements 4 of a cylindrical shape interposed to freely roll between inner rolling faces 2a, 2b formed on the outer peripheral surface of a shaft 2 arranged inside the outer ring 3 and the outer rolling faces 3a, 3b of the outer ring 3, and the seal member 6 having a fixing part 60a fixed to the outer peripheral surface of the outer ring 3 and a seal part 61 formed radially inward from the fixing part 60a to seal between the outer ring 3 and the shaft 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bearing for a water pump, and more particularly to a bearing for a water pump used for a cooling water pump in an internal combustion engine of an automobile.

  In recent years, the load applied to the engine side of the bearing for the water pump has increased with the increase in engine output and load capacity.

  Conventionally, this type of water pump bearing includes a rotating shaft that functions as an inner ring of the bearing, an outer ring disposed on the outer periphery of the rotating shaft, and a double-row rolling mechanism interposed between the outer ring and the rotating shaft. There is a moving body, and the internal space is sealed by a front side seal member and a rear side seal member (for example, Patent Document 1).

  The rotary shaft has an inner rolling surface for rolling the double row rolling elements on the outer peripheral surface, and is rotatably arranged in a bearing assembly cylinder of the pump housing. A pulley is attached to the front end portion of the rotating shaft via a pulley seat, and an impeller for a water pump is attached to the rear end portion thereof.

  The outer ring has an outer rolling surface on the inner circumferential surface for rolling the double row rolling elements, is fixed in a bearing assembly cylinder of the pump housing, and is entirely formed of a cylindrical member.

  In the double row rolling elements, one side row rolling element having a relatively small load is constituted by a ball, and the other side row rolling element having a relatively large load is constituted by a roller. The rolling elements in one side row are disposed on the rear side of the water pump bearing and are held by a ball cage. Further, the rolling elements in the other side row are disposed on the front side of the water pump bearing and are held by a roller holder.

  With the above configuration, when torque is transmitted from the engine side of the vehicle to the pulley via the driving force transmission member, the pulley rotates together with the rotating shaft. Since the impeller is attached to the rotating shaft, torque from the engine side is also transmitted to the impeller, and the impeller rotates together with the rotating shaft.

Japanese Patent Laid-Open No. 9-25817

  By the way, according to the water pump bearing shown in Patent Document 1, the cylindrical (roller) receives a high load from the rotating shaft side and moves toward the seal member together with the roller retainer, and the roller retainer interferes with the seal member. There are things to do. This is because the roller is arranged between the inner ring and the outer ring with a dimensional margin, so that the roller rolls in a state inclined with respect to the axial direction of the rotating shaft and the outer ring, and there is a thrust force that moves the roller to the seal member. By acting, the roller presses the seal member together with the roller cage. For this reason, even when an excessive load is applied for a long time, there is a problem that the strength of the seal member must be sufficiently ensured so that the roller member does not push out the seal member.

  Accordingly, an object of the present invention is to provide a bearing for a water pump that can suppress the roller and the roller retainer from pushing out the seal member.

  In order to achieve the above object, the present invention provides a water pump bearing to be assembled in a bearing assembly cylinder of a pump housing, which is press-fitted into the bearing assembly cylinder and has a rolling surface on an inner peripheral surface. And a cylindrical shape interposed between the rolling surface formed on the outer peripheral surface of the inner rotating member disposed on the inner side of the outer ring and the rolling surface of the outer ring. A rolling element, a fixed part fixed to the outer peripheral surface of the outer ring, and a seal that is formed by bending inwardly in the radial direction from the fixed part and seals between the outer ring and the inner rotating member Provided is a bearing for a water pump provided with a seal member having a portion.

  According to the present invention, it is possible to suppress the roller and the roller holder from pushing out the seal member.

Sectional drawing shown in order to demonstrate the whole water pump bearing which concerns on embodiment of this invention. Sectional drawing shown in order to demonstrate the principal part of the bearing for water pumps concerning embodiment of this invention.

[Embodiment]
(Whole structure of water pump bearing)
FIG. 1 shows the entire water pump bearing. FIG. 2 shows a main part of the bearing for the water pump. As shown in FIG. 1, the water pump bearing 1 includes a shaft 2 as an inner rotating member that also serves as an inner ring of the bearing 1, an outer ring 3 disposed on the outer periphery of the shaft 2, and the outer ring 3 and the shaft 2. And a pair of sealing members 6 and 7 for sealing between the shaft 2 and the outer ring 3 outside the rolling elements 4 and 5, and a pump housing 8. The bearing assembly cylinder 9 is assembled by press-fitting.

(Configuration of shaft 2)
As shown in FIG. 1, the shaft 2 has inner rolling surfaces 2 a and 2 b for rolling the double-row rolling elements 4 and 5, respectively, on the outer peripheral surface, and in the bearing assembly cylinder 9 of the pump housing 8. It is arranged so as to be rotatable around the central axis O. The shaft 2 is configured such that one inner rolling surface 2a functions as a rolling element for the rolling element 4, and the other inner rolling surface 2b functions as a part for rolling the rolling element 5. A pulley 11 is attached to the front side (left side in FIG. 1) of the shaft 2 via a pulley seat 10, and an impeller 12 for a water pump is attached to the rear side (right side in FIG. 1). Yes.

  The pulley 11 is connected to the engine side via a driving force transmission belt (not shown). The impeller 12 has a base portion 12a and a blade portion 12b, and is rotatably accommodated in the pump housing 8. Thus, when the pulley 11 receives a driving torque from the engine side, the shaft 2 and the impeller 12 are rotationally driven around the central axis O, and the engine coolant is circulated by the impeller 12.

  The pump housing 8 has an accommodating space 8a for accommodating the impeller 12 therein, and a through hole 8b communicating with the accommodating space 8a. The pump housing 8 is disposed on the rear side of the water pump bearing 1, and the interior thereof is a housing sealing member. 13 is sealed.

  The bearing assembling cylinder 9 is integrally formed on the outer peripheral edge of the through hole 8b in the pump housing 8, and is formed by a cylindrical member that opens to the outside and communicates with the housing space 8a. The cylinder 9 for bearing assembly is set to a dimension in which the cylinder thickness gradually increases from the opening end on the pump drive source side (left side in FIG. 1) along the press-fitting direction (arrow a direction) of the water pump bearing 1. Has been.

(Configuration of outer ring 3)
As shown in FIG. 1, the outer ring 3 has outer rolling surfaces 3 a and 3 b for rolling the double-row rolling elements 4 and 5 on the inner circumferential surface, and is disposed on the outer periphery of the shaft 2. It is press-fitted into a bearing assembly cylinder 9 of the housing 8 and fixed. Further, the outer ring 3 is press-fitted into the inner peripheral surface of the bearing assembling cylinder 9, and is formed closer to the pump drive source than the barrel 3c and has a smaller outer diameter than the barrel 3c. 3d, and the whole is formed by a cylindrical member that opens in both directions along the central axis O. The outer ring 3 is configured such that one outer rolling surface 3a rolls the rolling element 4 and the other outer rolling surface 3b rolls the rolling element 5. The outer rolling surface 3a is formed across the trunk portion 3c and the trunk portion 3d.

(Configuration of rolling elements 4 and 5)
As shown in FIG. 1, the rolling elements 4 in one side row are composed of rollers having a cylindrical rolling surface, and are arranged on the front side of the water pump bearing 1, that is, on the pump drive source side of the bearing assembly cylinder 9. And is held by a roller holder 14.

  As shown in FIG. 1, the rolling elements 5 in the other side row are made of steel balls and are arranged on the rear side of the water pump bearing 1, that is, on the pump side of the bearing assembly cylinder 9 (on the side opposite to the pump drive source side). And is held by a ball cage 15.

(Configuration of seal members 6 and 7)
The seal members 6 and 7 are opposed to each other via the rolling elements 4 and 5 and are disposed between the shaft 2 and the outer ring 3. Since the seal members 6 and 7 have substantially the same configuration, only the seal member 6 on the pump drive source side will be described. In addition, about the seal member 7 of the pump side, the code | symbol of each site | part is attached | subjected corresponding to the code | symbol of each site | part of the seal member 6 (for example, the core part of the seal member 7 respond | corresponds to the core part 60 of the seal member 6). 70, and 71 is assigned to the seal portion of the seal member 7 in correspondence with the seal portion 61 of the seal member 6, respectively).

  As shown in FIG. 2, the seal member 6 has a core portion 60 and a seal portion 61, and the core portion 60 is fixed to the outer peripheral surface of the small-diameter body portion 3 d of the body portions 3 c and 3 d of the outer ring 3. .

  The core portion 60 is made of a material such as a metal having higher rigidity than the seal portion 61, and is a cylindrical fixed portion 60a that is press-fitted into the outer peripheral surface of the body portion 3d of the outer ring 3. A pump drive source for the fixed portion 60a The bottom portion 60b is formed integrally with the bottom portion 60b and formed radially inward from the axial end portion of the fixed portion 60a. A shaft insertion hole 60c through which the shaft 2 is inserted is provided at the center of the bottom 60b, and the core 60 is formed as a bottomed cylindrical member as a whole. Further, the inner diameter of the shaft insertion hole 60c of the core portion 60 is formed smaller than the outer diameter with respect to the central axis O of the end portion 14a on the pump drive source side of the roller holder 14, and the roller holder 14 has moved in the axial direction. In this case, the end surface in the axial direction of the roller retainer 14 is configured to contact the bottom portion 60b.

  The seal portion 61 includes a base piece 61a and tongue pieces 61b and 61c, and is entirely formed of an elastically deformable annular member made of, for example, nitrile rubber.

  The base piece 61b is integrally formed on the outer peripheral surface of the fixed portion 60a of the core portion 60, the surface on the pump drive source side of the bottom portion 60b, and the inner peripheral side surface of the shaft insertion hole 60c, for example, by baking.

  The tongue pieces 61b and 61c are integrally provided on the inner side of the base piece 60b, and the tip portion on the inner peripheral side comes into contact with the outer peripheral surface of the shaft 2 so as to seal the space between the outer ring 3 and the shaft 2 from the outside. Is formed. The tongue piece 61b is arranged closer to the pump drive source than the base piece 61a, and the tongue piece 61c is arranged closer to the pump than the base piece 61a. And the tongue pieces 61b and 61c are comprised so that the outer peripheral surface of the shaft 2 may be slidably contacted when the shaft 2 rotates.

  The seal member 7 may be attached to the inner peripheral surface of the outer ring 3 instead of being attached to the outer peripheral surface.

(Assembly method of seal member 6)
Next, a method for assembling the seal member 6 will be described with reference to FIG.

  As shown in FIG. 2, the seal member 6 is assembled from the end on the pump drive source side to the core portion 60 on the body 3 d of the outer ring 3 in which the rolling elements 4 are arranged on the inner peripheral surface together with the roller holder 14 in advance. This is done by press-fitting the fixed portion 60a. At this time, the tongue pieces 61b and 61c are elastically deformed so that the shaft 2 is inserted.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

  Since the core portion 60 is pressed against the outer peripheral surface of the body portion 3d of the outer ring 3, the contact area between the seal member and the outer ring can be increased compared to the case where the seal member is mounted on the inner peripheral surface of the outer ring. The sealing member 6 can be fixed more firmly. For this reason, even if the rolling element 4 receives a high load from the shaft 2 side and moves together with the roller retainer 14 to the seal member 6 on the front side, the seal member 6 does not move even if the roller retainer 14 interferes with the seal member 6. The roller ring 14 and the rolling element 4 can be prevented from jumping out of the water pump bearing 1 without being detached from the outer ring 3. Further, since the seal member 6 is fixed to the outer peripheral surface of the body portion 3d, the thickness T of the core portion 60 is relatively larger than the case where the seal member is attached to the inner peripheral surface of the outer ring as in the prior art ( T = 0.8 to 1.2 mm: the thickness t of the conventional core can be set to t = 0.5 to 0.8 mm), and the deformation of the seal member 6 due to the interference of the roller cage 14 is suppressed. can do. Furthermore, the axial length of the outer ring can be shortened compared with the case where the seal member is attached to the inner peripheral surface of the outer ring.

  As mentioned above, although the bearing for water pumps of this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment, In the range which does not deviate from the summary, it implements in various aspects. For example, the following modifications are possible.

(1) In the above embodiment, the case where the rolling element 4 on the pump drive source side, that is, the front side of the bearing assembly cylinder 9 is formed by a cylindrical roller has been described, but the present invention is not limited to this, Not only the rolling elements on the front side but also the rolling elements on the rear side may be formed by cylindrical rollers. That is, according to the present invention, it is sufficient that at least one of the bearing assembly cylinders includes a double row rolling element including a rolling element composed of a roller. In addition, the rolling elements do not have to be in a double row, and may be a single row of rolling elements in which a plurality of rollers are arranged along the circumferential direction of the shaft 2.

(2) Although the case where the rolling element 4 on the pump drive source side is a cylindrical roller has been described in the above embodiment, the present invention is not limited thereto, and may be another rolling element such as a needle roller. .

  DESCRIPTION OF SYMBOLS 1 ... Water pump bearing, 2 ... Shaft, 2a, 2b ... Inner rolling surface, 3 ... Outer ring, 3a, 3b ... Outer rolling surface, 3c ... Large diameter trunk | drum, 3d ... Small diameter trunk | drum, 4, DESCRIPTION OF SYMBOLS 5 ... Rolling element, 6, 7 ... Seal member, 60 ... Core part, 60a ... Fixed part, 60b ... Bottom part, 60c ... Shaft insertion hole, 60b ... Base piece, 61 ... Seal part, 61b, 61c ... Tongue piece, 7 DESCRIPTION OF SYMBOLS ... Seal member, 70 ... Core part, 71 ... Seal part, 8 ... Pump housing, 8a ... Accommodating space, 8b ... Through-hole, 9 ... Bearing assembly cylinder, 10 ... Pulley seat, 11 ... Pulley, 12 ... Impeller, 12a ... Base, 12b ... Blades, 13 ... Housing sealing member, 14 ... Roller cage, 15 ... Ball cage, O ... Center axis

Claims (2)

A water pump bearing assembled in a bearing assembly cylinder of a pump housing,
An outer ring press-fitted into the bearing assembly cylinder and having a rolling surface on the inner peripheral surface;
A cylindrical rolling element interposed between the rolling surface formed on the outer peripheral surface of the inner rotating member disposed inside the outer ring and the rolling surface of the outer ring so as to be freely rollable;
A fixing portion that is fixed to the outer peripheral surface of the outer ring, and a sealing member that is formed radially inward from the fixing portion and has a sealing portion that seals between the outer ring and the inner rotating member. Water pump bearing. The outer ring has two large and small trunks with different outer diameters,
2. The water pump bearing according to claim 1, wherein the sealing member is fixed by press-fitting the fixing portion into an outer peripheral surface of a small-diameter body portion of the two large and small body portions.

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