JP2967369B2 - Water pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft having an axial inner end protruding into a pump chamber formed in a pump case. The rotary shaft is rotatably supported by the pump case. The present invention relates to a water pump provided with a power transmission rotary wheel and a mechanical seal provided between a pump case and a rotary shaft.

[0002]

2. Description of the Related Art Conventionally, such a water pump is known, for example, from Japanese Utility Model Laid-Open Publication No. Sho 61-169230, and the water pump is disposed inside the bearing along the axial direction of a rotating shaft supported by a pump case via a bearing. On the side, a mechanical seal is interposed between the pump case and the rotating shaft,
In order to prevent water leaking from the mechanical seal from entering the bearing, a baffle plate is provided on the rotating shaft between the bearing and the mechanical seal, and a discharge hole is provided in the pump case for discharging water. Have been.

[0003]

However, it is difficult to completely discharge the water from the discharge hole by the baffle plate which rotates with the rotating shaft in the above-mentioned conventional apparatus.
It is difficult to reliably prevent water vapor from entering the bearing.

The present invention has been made in view of such circumstances, and has as its object to provide a water pump capable of reliably preventing water from entering a bearing means.

[0005]

According to the first aspect of the present invention, there is provided a pump case, wherein a cylindrical support portion surrounding a rotary shaft is provided in a pump case, and the pump case is provided outwardly from the support portion. cylindrical power transmission rotary wheel surrounding the support portion is integrally coupled to the outer end of the rotary shaft that protrudes, the rotary ring
A bearing means for the rotating shaft combination is provided only between the inner surface of the power transmission rotating wheel and the outer surface of the supporting portion, and the supporting portion of the supporting portion on the outer side of the mechanical seal along the axial direction of the rotating shaft; A plurality of seal members are disposed between the inner surface and the rotary shaft at substantially the same position as the bearing unit along the axial direction of the rotary shaft and concentrically with the bearing unit. Is filled.

According to the first aspect of the present invention, leakage of moisture from the mechanical seal side to the bearing means is prevented by the seal member and the grease filled between the seal members is used. It is possible to improve the water resistance of the bearing means by stopping the leakage of water, and furthermore , to the inside and outside of the cylindrical support of the pump case.
And the sealing member and the bearing means extend along the axial direction of the rotating shaft.
Are arranged concentrically at almost the same position,
Can be arranged at the position where the displacement of the rotating shaft is the smallest, improving the sealing performance of the seal member and the water retention of the grease, and compensating the water pump in the axial direction of the rotating shaft.
Configuration. In addition, the rotating shaft and rotating wheel are combined and integrated.
Bearing means only between the inner surface of the rotating wheel and the outer surface of the support.
Installation, the number of bearings is minimized and the number of parts is reduced.
Can be reduced and leakage from the mechanical seal
It is possible to effectively prevent infiltrated moisture from entering the bearing means.

According to the second aspect of the present invention, the pump case is provided with a cylindrical support portion surrounding the rotary shaft, and a support portion is provided at an outer end of the rotary shaft projecting outward from the support portion. cylindrical power transmission rotary wheel surrounding the are integrally joined, the bearing means for the rotation wheel-rotation shaft coupling member,
It is interposed only between the inner surface of the power transmission rotating wheel and the outer surface of the supporting portion, and is located between the inner surface of the supporting portion and the rotating shaft on the outer side of the mechanical seal along the axial direction of the rotating shaft ,
A substantially same position as the bearing means along the axial direction of the rotating shaft.
A sealing member is provided interposed concentrically with the bearing means, and a fan disposed in an annular chamber formed in a pump case surrounding the rotating shaft between the sealing member and the mechanical seal. And a passage for allowing air to flow between the annular chamber and the outside is provided in at least one of the rotating shaft and the pump case, and a drain hole for discharging water in the annular chamber to the outside is provided in the pump case.

[0008] According to the configuration of the second aspect of the present invention, moisture leakage from the mechanical seal side is prevented by the seal member.
It is possible to improve the water resistance of the bearing means by stopping
And inside and outside of the cylindrical support of the pump case.
In the circumference, the sealing member and the bearing means are in the axial direction of the rotating shaft.
Are arranged concentrically at almost the same position along the
Can be placed at the position where the rotation axis displacement is the smallest.
To improve the sealing performance of the seal
The water pump can be made compact in the axial direction.
Also, the rotating shaft and rotating wheel are combined and integrated, and the bearing means is
By interposing only between the inner surface of the
Receiving means can be minimized and the number of parts can be reduced.
In both cases, the moisture leaking from the mechanical seal invades the bearing means.
Can be effectively avoided. Also, especially in annular chambers
Rotating the fan effectively drains water to the outside
As well as cooling the mechanical seal and seal members.
To improve their sealing performance
Can be

Furthermore according to claim 3 invention According described, the pump casing is provided a cylindrical support portion surrounding the rotary shaft, the outer end of the rotary shaft projecting outward from the support portion, their
From the outer end through a collar portion which overhangs radially outward cylindrical power transmission rotary wheel surrounding the support portion is integrally coupled, a bearing means for the rotation wheel-rotation shaft coupling member, A seal member is provided only between the inner surface of the power transmission rotary wheel and the outer surface of the support portion, and a seal member is provided between the inner surface of the support portion and the rotary shaft outside the mechanical seal along the axial direction of the rotary shaft. interposed, the flange portion, at least one through hole having an axis parallel to the axis of the rotary shaft is provided, this magnetic
The hole is formed between the outer ring and the outer ring of the bearing means.
And the bearing seal member to be cooled .

[0010] According to the configuration of the third aspect of the present invention, moisture leakage from the mechanical seal side is prevented by the seal member.
It is possible to improve the water resistance of the bearing means by stopping
Function, and the rotating shaft and rotating wheel
Means are interposed only between the inner surface of the rotating wheel and the outer surface of the support.
As a result, the number of bearings can be minimized and the number of parts can be reduced.
And the moisture leaking from the mechanical seal
Intrusion into the bearing means can be effectively avoided. Especially
The inside and outside of the bearing means are attached to the flange connecting the rotating shaft and the rotating wheel.
Rings and bearing seal members that seal between the outer and inner rings
Cooling of sealing member is possible by forming opposing through holes
Not only the cooling effect of the bearing means and the bearing seal member
And the inner surface and support of the power transmission wheel
The work of mounting the bearing means between the outer surfaces of the
The degree also improves. In addition, the above-mentioned through hole is
Can be installed as far away as possible in the direction
The through hole can be formed large while suppressing the decrease in rigidity.
The cooling effect of the bearing means etc. can be further enhanced and the pump
Lightening is achieved.

According to the fourth aspect of the present invention, the pump case is provided with a cylindrical support portion surrounding the rotary shaft, and the support portion is provided at an outer end of the rotary shaft projecting outward from the support portion. The surrounding cylindrical power transmission rotary wheel is integrally connected, bearing means is provided between the inner surface of the power transmission rotary wheel and the outer surface of the support portion, and extends along the axial direction of the rotary shaft. A seal member is interposed between the inner surface of the support portion and the rotation shaft on the outer side of the mechanical seal, and an annular chamber formed in the pump case surrounding the rotation shaft between the seal member and the mechanical seal. A passage communicating with the rotating shaft is provided at the outer end of the rotating shaft.

According to the structure of the invention, the sealing member prevents moisture from leaking from the mechanical seal to the bearing means, thereby improving the water resistance of the bearing means. It is possible to cool the seal member by flowing air through a passage provided in the rotating shaft.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention. FIG. 1 is a side view of an engine provided with a water pump, FIG. 2 is a front view of the water pump, and FIG. FIG. 3 is a sectional view taken along line 3-3 of FIG.

First, in FIG. 1, a water pump P
The water pump P is provided on the side surface of the engine body 1 of the DOHC type engine for an automobile, and the power from the crankshaft 2 is transmitted to the water pump P via the wrapping transmission 4. The winding transmission 4 is provided with a pair of valve cam shafts 5, 6 rotatably supported on the upper part of the engine body 1 in parallel with the crankshaft 2, and an adjusting mechanism for driving the water pump P. A drive pulley 7 fixed to the crankshaft 2, a driven pulley 8 for driving the water pump P, and driven pulleys 9 and 10 fixed to the two-way valve camshafts 5 and 6, respectively. The timing belt 11 is suspended by the driving pulley 7.
The water pump P and the double-acting valve camshafts 5 and 6 are driven to rotate by driving 1 in the traveling drive direction indicated by the arrow 12. In addition, a tensioner 13 for adjusting the tension is elastically slidably brought into contact with the timing belt 11 between the driving pulley 7 and the driven pulley 8.

In FIGS. 2 and 3, a pump case 14 of the water pump P defines a pump chamber 16 between the engine body 1 and the engine body 1 and is fixed to a side surface of the engine body 1. An impeller 18 is press-fitted and fixed to an axial inner end of a rotary shaft 17 which is rotatably supported by the pump case 14 and protrudes into the pump chamber 16. The rotary shaft 17 protrudes from the cover 15. The driven pulley 8 as a power transmission rotating wheel is provided at an outer end of the driven pulley 8.

In the pump case 14, the cover 15 is integrally provided with a support portion 20 formed in a cylindrical shape, and the rotary shaft 17 is disposed coaxially through the support portion 20. At the outer end of the rotating shaft 17 that protrudes outward from the support portion 20, a flange portion 21 that protrudes radially outward is provided, and a driven pulley formed in a cylindrical shape coaxially surrounding the support portion 20. 8 is integrally connected to the radially outer end edge of the flange portion 21 , thereby forming the rotating shaft / rotating wheel combined body U.
Re that.

Bearing for the combined rotating shaft and rotating wheel U
A double row ball bearing 22 as a means is interposed only between the inner surface of the driven pulley 8 and the outer surface of the support portion 20.
Therefore, the rotating shaft 17 is rotatably supported by the cover 15, that is, the pump case 14 via the double row ball bearing 22. Moreover, the double row ball bearing 22 is provided with bearing seal members 22a, 22a, respectively, between both ends of the inner ring and the outer ring in the axial direction, and these bearing seal members 22a, 22a are inserted into the double row ball bearing 22. To prevent water and dust from entering. The flange 21 has an end portion of the double row ball bearing 22 , that is, an inner ring, an outer ring and a bearing seal member 22.
At least one, for example, four through-holes 23 facing each end of a are bored at intervals in the circumferential direction.

The inner surface of the cover 15 is integrally provided with a cylindrical portion 24 protruding toward the pump chamber 16 so as to coaxially surround the inner end of the support portion 20.
A conventionally known mechanical seal 25 is interposed between the rotary shaft 4 and the rotary shaft 17. Further, at an axial position substantially corresponding to the double row ball bearing 22, a pair of seal members 26, 26 are provided between the inner surface of the support portion 20 and the outer surface of the rotary shaft 17 at an axial interval. The space between the seal members 26 is filled with grease 27. The grease 27 is provided between the sealing members 26 and 26 and the rotating shaft 17.
And a function of trapping the leaked moisture even if moisture leaks from the seal member 26 on the inner side in the axial direction of the rotating shaft 17.

The cover 15 is disposed between the mechanical seal 25 and the seal member 26 on the inner side along the axial direction of the rotary shaft 17.
An annular chamber 28 surrounding the rotating shaft 17 is formed therein.
In the annular chamber 28, the mechanical seal 2 is attached to the rotating shaft 17.
The fan 29 arranged toward the fifth side is fixed. The fan 29 has a plurality of blades along the radial direction of the rotating shaft 17.
A communication hole 30 opened inside 9 is formed along one diameter line. In order to form an air passage in cooperation with the communication hole 30, an introduction hole 31 having an inner end communicating with the communication hole 30 is formed coaxially with the rotating shaft 17, and an outer end of the introduction hole 31 is formed. It is opened to the outside by a widened portion 31a having a tapered shape or a stepped shape to expand the axially outward side to improve the air introduction. Therefore, the rotating shaft 17, that is, the fan 2
By the rotation operation of 9, air is introduced from the outside into the annular chamber 28 through the introduction hole 31 and the communication hole 30, and a centrifugal force is applied to the introduced air.

By providing the widened portion 31a at the outer end of the introduction hole 31 as described above, there is a concern that displacement of the rotating shaft 17 and associated sealing failure of the sealing members 26, 26 may occur. The shaft 17 is supported by interposing a double row ball bearing 22 between the driven pulley 8 surrounding the support 20 and the support 20,
Since an excessive load is not applied to the rotating shaft 17, there is no danger that the displacement of the rotating shaft 17 and the resulting sealing failure will occur, and the air can be better introduced into the introduction hole 31.

On the other hand, the cover 15 is provided with a drain hole 32 and an air passage 33 having an outer end opened to the outside and an inner end opened to the annular chamber 28. The drain hole 32 is formed in the lower part of the cover 15 so as to be located radially outward of the rotary shaft 17 from the inner end to the outer end along the rotation direction 34 of the rotary shaft 17. The air passage 33 is formed in the upper portion of the cover 15 so that the angle between the axis of the air passage 33 and the axis of the drain hole 32 is an acute angle.

Next, the operation of this embodiment will be described. When the water pump P is operated, the space between the pump chamber 16 and the annular chamber 28 is sealed by a mechanical seal 25, and water in the pump chamber 16 is released from the annular chamber. However, it is difficult to completely seal with the mechanical seal 25, and the annular chamber 28 of a small amount of water containing water vapor evaporated by frictional heat in the mechanical seal 25.
Leaks to the unavoidable. However, in the annular chamber 28, air is introduced from the outside through the air passage formed by the introduction hole 31 and the communication hole 30 by the fan 29, and centrifugal force acts on the introduced air. Therefore, centrifugal force also acts on the water and steam leaking from the mechanical seal 25 to the annular chamber 28, and a part of the steam and the water are forced out of the drain hole 32, and the remaining steam is forced out of the air passage 33. Is discharged. In addition, since the air flows in the annular chamber 28, the mechanical seal 25 can be cooled, and the generation of frictional heat in the mechanical seal 25 can be suppressed as much as possible.

Although it is difficult to completely remove moisture from the annular chamber 28 by the function of the fan 29, a pair of seal members 26, 26 are arranged between the annular chamber 28 and the double row ball bearing 22. Even if moisture leaks from the inner sealing member 26, the leakage of moisture can be stopped by the grease 27 between the two sealing members 26, 26. Can be reliably prevented from leaking water, and the water resistance can be improved. The two seal members 26, 26 are also cooled by the airflow generated by the fan 29.

Further, the two seal members 26, 26 are provided at the position where the displacement of the rotating shaft 17 is the smallest when an external load is applied to the rotating shaft 17, that is, at the substantially same axial position as the double row ball bearing 22, and the rotation of the supporting portion 20 Since it is interposed between the shafts 17, it is possible to exert an excellent sealing effect on the two sealing members 26, 26, to further improve the water resistance, and to shorten the length of the support portion 20 as much as possible. Thus, the water pump P can be made compact.

Further, by providing a plurality of through holes 23 in the flange 21 connecting the rotary shaft 17 and the driven pulley 8, the double row ball bearing 22 and the seal members 26, 26 can be cooled, and The mounting operation of the double row ball bearing 21 can be easily performed by using the through holes 23, and the mounting accuracy is also improved.

As another embodiment of the present invention, as shown in FIG. 4, a single seal member 26 may be interposed between the rotating shaft 17 and the support portion 20. Although the sealing performance is slightly reduced as compared with the conventional one, it is possible to more reliably prevent the penetration of moisture into the double row ball bearing 22 as compared with the conventional one.

In each of the embodiments described above, the double row ball bearing 22 is used as the bearing means. However, the present invention can be applied to a case using other bearing means such as a roller bearing and a slide bearing.

[0029]

As described above, according to the first aspect of the present invention,
It is possible to improve the water resistance of the bearing means by stopping water leakage from the mechanical seal side with the seal member and grease between the seal members, and furthermore, the pump
Sealing members and seals are provided on the inner and outer circumferences of the cylindrical support
And the bearing means are located at almost the same position along the axis of the rotating shaft.
Since the seal members are arranged concentrically, the seal member can be arranged at a position where the displacement of the rotating shaft is the smallest , thereby improving the sealing property of the seal member and the water holding force of the grease, and further improving the water resistance of the bearing means. Of the rotating shaft
The water pump can be made compact in the axial direction.
it can. In addition, the rotating shaft and rotating wheel are combined and integrated, and bearing means
Is installed only between the inner surface of the rotating wheel and the outer surface of the support.
As a result, the number of bearings can be minimized and the number of parts can be reduced.
Not only contributes to cost savings, but also
Prevent moisture leaking from the seal from entering the bearing means
It can be avoided effectively.

According to the second aspect of the present invention, it is possible to improve the water resistance of the bearing means by stopping water leakage from the mechanical seal side with the seal member, and furthermore, to improve the water resistance of the pump case. Of the outer circumference
And the bearing means are substantially the same along the axis of the rotating shaft.
Since it is arranged concentrically at one position, the seal member can be rotated
It can be placed at the position where the shaft displacement is the smallest,
Improves sealing performance and further improves the water resistance of bearing means
And the water
The pump can be made compact. Also rotating shaft
・ The rotating wheel is connected and integrated, and the bearing means is supported on the inner surface of the rotating wheel.
Since the bearings are interposed only between the outer surfaces of the
Reduces the number of parts and reduces costs
As well as leakage from the mechanical seal.
To effectively prevent spilled water from entering the bearing means.
Can be. Also , since the fan is rotated in the annular chamber to effectively discharge moisture to the outside and cool the mechanical seal and the seal member ,
The sealing performance can be further improved, and the water resistance of the bearing means can be further improved.

[0031] According to the third aspect of the invention, it is possible to improve the water resistance of the bearing means so as to stop the water leaking from the mechanical seal side seal member, deer
Also integrates the rotating shaft and rotating wheel and integrates the bearing means
The bearing is installed only between the inner surface and the outer surface of the support,
The number of parts is reduced and the number of parts can be reduced.
As well as mechanical
Effectively prevents moisture leaking from the bearings from entering the bearing means.
Can be avoided. Also especially connected between the rotating shaft and rotating wheel
To the outer ring of the bearing means and the inner and outer rings of the bearing means.
Formed through holes facing the bearing seal member to be sealed
Since the cooling can and Do Rubakari of the seal member, the bearing hand
The cooling effect of the step and bearing seal members is also improved, and the work of mounting the bearing means between the inner surface of the power transmission rotating wheel and the outer surface of the support portion is facilitated, and mounting accuracy is also improved. Further above
The through-hole is located in the flange as far as possible in the radial direction from the rotation axis.
To reduce the rigidity of the flange
The through hole can be formed large, and therefore the cooling effect of the bearing means etc.
The pump can be further improved and the pump can be reduced in weight.
You.

Further, according to the present invention, it is possible to improve the water resistance of the bearing means by preventing the leakage of water from the mechanical seal side with the seal member. When the air flows through the passage, the seal member can be cooled.

[Brief description of the drawings]

FIG. 1 is a side view of an engine provided with a water pump according to one embodiment of the present invention.

FIG. 2 is a front view of the water pump.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a sectional view corresponding to FIG. 3 of another embodiment of the present invention.

[Explanation of symbols]

8 Driven Pulley as Power Transmission Rotary Wheel 14 Pump Case 16 Pump Chamber 17 Rotating Shaft 20 Support 21 Collar 22 Double Row Ball Bearing as Bearing 23 Through Hole 25 Mechanical Seal 26 Seal Member 27 Grease 28 Annular Chamber 29 Fan Reference Signs List 30 communication hole forming air passage 31 introduction hole forming air passage 32 drain hole 33 air passage P water pump U rotating shaft / rotating wheel combination

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shoji Isobe 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Research Institute Co., Ltd. (56) References JP-A-2-55899 (JP, A) Sho Akai 61-137900 (JP, U) Fully open Showa 61-169230 (JP, U) Fully open Showa 61-144219 (JP, U) Really open 2-144693 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F04D 29/04 F04D 29/42 F04D 29/58

Claims (4)

(57) [Claims] A rotary shaft (17) having an axial inner end protruding into a pump chamber (16) formed in a pump case (14) is rotatably supported by the pump case (14), and is rotatable. In a water pump provided with a power transmission rotating wheel (8) at an axially outer end of (17) and a mechanical seal (25) between the pump case (14) and the rotating shaft (17), the pump case ( 14) is provided with a cylindrical support part (20) surrounding the rotation shaft (17), and a support part (2) is provided at an outer end of the rotation shaft (17) projecting outward from the support part (20).
0) cylindrical power transmitting rotating wheel (8 surrounding the) are integrally coupled, against the rotation wheel-rotation shaft coupling member (U)
Bearing means (22) is provided only between the inner surface of the power transmission rotating wheel (8) and the outer surface of the support portion (20), and extends along the axial direction of the rotating shaft (17). ), Between the inner surface of the support portion (20) and the rotating shaft (17), at substantially the same position as the bearing means (22) along the axial direction of the rotating shaft (17). A plurality of seal members (2) arranged concentrically with (22).
6) A water pump, wherein grease (27) is filled between the seal members (26). 2. A rotary shaft (17) having an axial inner end protruding into a pump chamber (16) formed in the pump case (14) is rotatably supported by the pump case (14), and is rotatable. In a water pump provided with a power transmission rotating wheel (8) at an axially outer end of (17) and a mechanical seal (25) between the pump case (14) and the rotating shaft (17), the pump case ( 14) is provided with a cylindrical support part (20) surrounding the rotation shaft (17), and a support part (2) is provided at an outer end of the rotation shaft (17) projecting outward from the support part (20).
0) cylindrical power transmitting rotating wheel (8 surrounding the) are integrally coupled, against the rotation wheel-rotation shaft coupling member (U)
Bearing means (22) is provided only between the inner surface of the power transmission rotating wheel (8) and the outer surface of the support portion (20), and extends along the axial direction of the rotating shaft (17). ), Between the inner surface of the support portion (20) and the rotating shaft (17) , along the axial direction of the rotating shaft (17).
The bearing means at substantially the same position as the bearing means (22).
A seal member (26) arranged concentrically with (22) is interposed, and a rotary shaft (17) is surrounded between the seal member (26) and the mechanical seal (25) in the pump case (14). A fan (29) arranged in the formed annular chamber (28) is fixed to the rotating shaft (17), and the annular chamber (2) is fixed.
8) and a passage (30, 3) for allowing air to flow between the outside and
1, 33) are the rotating shaft (17) and the pump case (1).
A drain hole (32) provided in at least one of (4) and discharging water in the annular chamber (28) to the outside is provided in the pump case (1).
Water pump characterized by being provided in 4). 3. A rotary shaft (17) having an axial inner end protruding into a pump chamber (16) formed in the pump case (14) is rotatably supported by the pump case (14). In a water pump provided with a power transmission rotating wheel (8) at an axially outer end of (17) and a mechanical seal (25) between the pump case (14) and the rotating shaft (17), the pump case ( 14) is provided with a cylindrical support portion (20) surrounding the rotary shaft (17), and the outer end of the rotary shaft (17) projecting outward from the support portion (20) is provided at the outer end thereof. A cylindrical power transmission rotating wheel (8) surrounding the support portion (20) via a flange portion (21) projecting radially outward from the shaft.
Are integrally combined, and the rotating wheel and rotating shaft combined body (U)
Bearing means (22) for the power transmission rotating wheel (8)
Interposed only between the outer surface of the inner surface and the support part (20),
A seal member (26) is provided between the inner surface of the support portion (20) and the rotary shaft (17) on the outer side of the mechanical seal (25) along the axial direction of the rotary shaft (17), The flange (21) is provided with at least one through-hole (23) having an axis parallel to the axis of the rotating shaft (17) , and this through-hole (23) is provided in the bearing means (22).
Bearing seal member for sealing the outer ring and the inner ring and the outer ring
(22a) . A water pump characterized by being opposed to (22a) . 4. A rotary shaft (17) having an axial inner end projecting into a pump chamber (16) formed in the pump case (14) is rotatably supported by the pump case (14). In a water pump provided with a power transmission rotating wheel (8) at an axially outer end of (17) and a mechanical seal (25) between the pump case (14) and the rotating shaft (17), the pump case ( 14) is provided with a cylindrical support portion (20) surrounding the rotation shaft (17), and the support portion (2) is provided at the outer end of the rotation shaft (17) projecting outward from the support portion (20).
The power transmission rotary wheel (8), which is formed in a cylindrical shape and surrounds the power transmission rotary wheel (8), is integrally joined, and a bearing means (22) is provided between the inner surface of the power transmission rotary wheel (8) and the outer surface of the support portion (20). )
A support portion (2) is provided on the outer side of the mechanical seal (25) along the axial direction of the rotary shaft (17).
0) and between the rotating shaft (17) and the sealing member (2).
A passage (30) is provided between the seal member (26) and the mechanical seal (25), which surrounds the rotation shaft (17) and communicates with an annular chamber (28) formed in the pump case (14). , 31) are provided on the rotating shaft (17) so as to open at the outer end of the rotating shaft (17).