JPH0128320Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a horizontal internal combustion engine with a lift pump that is integrally equipped with a centrifugal lift pump at the end of the crankshaft. The present invention relates to the horizontal internal combustion engine with a water pump having a structure that prevents cavitation on the opposing surfaces of the mouth ring provided on the pump lid side and the liner ring on the pump lid side.

(Prior art) Conventionally, when driving a centrifugal water pump by directly connecting it to the output shaft of an internal combustion engine such as a horizontal diesel engine, a flywheel 2 is fixed to the end of the crankshaft as shown in Fig. 4. and said flywheel 2
An internal combustion engine 1 with an output shaft 3 protruding further laterally from the
and a water pump 5 with a pump shaft 4 protruding in the horizontal direction are installed on one common platform 6, and the output shaft 3 of the internal combustion engine 1 and the pump shaft 4 of the water pump 5 are installed on a common platform 6.
A water pump set is assembled by connecting these to each other using elastic joints 7, and this is transported to a work site and used.

However, in the conventional water pump set as described above, the installation interval between the internal combustion engine 1 and the water pump 5 is wide, which increases the volume and weight of the entire set, causing inconvenience in transportation, and the installation area of the common platform 6. The problem was that it was large and the installation location was restricted.

Therefore, in order to overcome the problems of the conventional water pump set, the applicant has developed a cylinder block 1 for a horizontal internal combustion engine, as shown in cross section in FIG.
A centrifugal water pump 17 has a flywheel 13 fixed to the end of a crankshaft 12 which is rotatably supported by a centrifugal water pump 17, and a spiral water passage 16 is provided on the outer surface of a lid 15 of a flywheel housing 14 surrounding the flywheel 13. An impeller 2 is integrally formed with a casing 18 by casting, and has a mouth ring 20 in an impeller housing chamber 19 at the center of the casing 18.
1, and the central boss portion of the impeller 21 is connected to the flywheel attachment side end 12a of the crankshaft 12 with or without the pump shaft 22, thereby making the water pump 17 compact. We previously proposed an internal combustion engine with an integrated centrifugal water pump. (Refer to Japanese Utility Model Application Publication No. 101700/1983) Therefore, in the above-mentioned internal combustion engine with a water pump, a water inlet 24 is formed at the inner end of the pump lid 23 fitted to the outer extended opening end of the impeller housing chamber 19. The mouth ring 2 is connected to the mouth ring 2 by the liner ring 25.
By surrounding the outer periphery of 0 with a slight gap all around, it is possible to prevent a decrease in pump efficiency due to leakage from this part.

(Problem to be solved by the invention) However, in such a conventional internal combustion engine with a water pump, when the piston on the inter-machine side reciprocates, the crankshaft 12 is slightly bent by the explosive load, and the reaction occurs. The impeller 21 is momentarily eccentric toward the head side in the reciprocating direction of the piston due to force and inertia force, and the air bubbles generated in the opposing gap (also referred to as a wear ring gap) between the mouth ring 20 and the liner ring 25 are crushed. There is a problem in that the so-called cavitation phenomenon occurs and the inner circumferential surface of the liner ring 25 and the outer circumferential surface of the mouth ring 20 corrode, and there remains room for further improvement in this respect.

In order to prevent the cavitation described above, it is possible to set the opposing gap between the mouth ring 20 and the liner ring 25 to be somewhat larger in consideration of the amount of eccentricity of the impeller 21, but in this case, leakage from the opposing gap all around the circumference may be considered. This is undesirable because it increases the volume and backflow, leading to a decrease in pump efficiency.

The present invention was developed by focusing on the problem of cavitation occurring in the opposing gap between the mouth ring on the impeller side and the liner ring on the pump case side, which conventional internal combustion engines with a water pump had. Of the entire peripheral wall of the liner ring that surrounds the outer circumferential surface, a pressure relief hole is provided in the wall on the side where the impeller is eccentric due to the explosion load of the internal combustion engine, and by preventing cavitation in this part, the opposing gap in other parts is reduced. The purpose is to make it possible to set it as small as before, thereby solving the above-mentioned problem.

(Means for Solving the Problems) The structure of the present invention for achieving the above object will be explained with reference to the accompanying drawings FIGS. 1 and 2.

In the horizontal internal combustion engine with a water pump of the present invention, a flywheel 35 fixed to an end 32a of a crankshaft 32 is surrounded by a flywheel housing 36, and an impeller housing chamber is located on the outer surface of the flywheel housing 36. A pump casing 41 of a centrifugal water pump 40 having a spiral water passage 39 on the outer periphery of the pump 38 is integrally formed, and an impeller 44 built in the impeller housing chamber 38 is attached to the flywheel mounting side of the crankshaft 32. While communicating with the end portion 32a, the outer peripheral surface of the mouth ring 47 of the impeller 44 is connected to the impeller housing chamber 3.
It has a structure in which a liner ring 48 formed at the inner end of the water inlet 46 of the pump lid 45 fitted to the outer extended opening end of the pump lid 45 surrounds the water inlet 46 with a slight opposing gap over the entire circumference. Of the entire circumferential wall of the liner ring 48, a pressure relief hole 50 is bored in the wall at a position on the head side in the reciprocating direction of the piston of the internal combustion engine, allowing the opposing gap and the impeller housing chamber 38 to communicate with each other.

(Function) In the horizontal internal combustion engine with a lift pump of the present invention having the above-mentioned configuration, the liner ring 48 of the pump lid 45, which faces the mouth ring 47 of the impeller 44 with a slight gap, is located at the head in the reciprocating direction of the piston. Impeller 4 due to side position, i.e. explosive load
4 has a pressure relief hole 50 that opens at the opposing gap at one end and opens at the impeller housing chamber 38 at the other end at the position on the eccentric side. Even if the air bubbles are reduced by
Corrosion due to cavitation is prevented.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a side view of a horizontal internal combustion engine with a water pump according to the present invention, and FIG. 2 is a plan view taken along the - arrow in FIG.

In these figures, 31 is a cylinder block of a horizontal diesel internal combustion engine, 32 is a crankshaft rotatably supported by the cylinder block 31 via a bearing member 33 and a bearing 34;
35 is a flywheel fixed to the output side end 32a of the crankshaft 32; 36 is a flywheel housing surrounding the flywheel 35 and fixed to the side surface of the cylinder block 31; 37;
is a lid member attached to close the outer opening of the flywheel housing 36, and the outer surface of the lid member 37 has a centrifugal water passage 39 provided on the outer periphery of the impeller housing chamber 38. A pump casing 41 of the water pump 40 is integrally formed by casting, and the end portion 3 of the crankshaft 32 is inserted through a shaft through hole 42 provided at the center of the lid member 37.
The other end of a fixed pump shaft 43 with one end fixed to 2a is inserted into the impeller housing chamber 38, and the pump shaft 43 is attached to the pump casing 41.
An impeller 44 is fixed thereto, which has a diameter smaller than the regular dimensions corresponding to the size of the engine and which has a displacement matching the output of the internal combustion engine.

Reference numeral 45 denotes a pump lid fitted to the outer extended opening end of the impeller housing chamber 38, and the pump lid 45 has a water inlet 46 in the center thereof to which a suction hose is connected, and the water inlet 45 is connected to the suction hose. At the inner end side of the inlet 46, the mouth ring 4 of the impeller 44
7 is integrally provided with a liner ring 48 that surrounds the outer circumferential surface with a slight opposing gap.

Of the entire circumference of the liner ring 48,
Engine piston reciprocating direction, i.e. pump center 0
cylinder head 4 of the engine in the horizontal direction including
A pressure relief hole 50 is bored in the wall on the side 9, and has one end opening in the gap facing the mouth ring 47 and the other end opening in the impeller housing chamber 38 inside the pump lid 45. ing.

As shown in FIG. 3, the pressure relief hole 50 has an elliptical shape with a minor axis approximately half the effective length l in the axial direction of the portion facing the mouth ring 47. The major axis d ₁ is 20 mm and the minor axis d ₂ is
Set to 10-12mm.

In the figure, 51 is a vane plate provided on the impeller 44;
52 is a discharge pipe placed on the upper surface of the pump casing 41 for guiding the pressurized water flowing out from the spiral water passage 39 to the drainage hose; 54 is an exhaust bed pipe whose lower end is connected to an exhaust port opened on the side surface of the cylinder head 49; 55 is an exhaust muffler; A fuel tank 57 placed on the front side is a radiator placed on the upper surface of the cylinder block 31 adjacent to the fuel tank 56.

The horizontal internal combustion engine with a lift pump of the present invention has the above-mentioned configuration, and its operation will be explained next.

First, when the impeller 44 fixed to the shaft end of the crankshaft 32 rotates at high speed in the impeller housing chamber 38 during engine operation, water sucked in from the water inlet 46 of the pump lid 45 flows through the blades 51 of the impeller 44.
The spiral water passage 39 receives centrifugal force due to the rotation of the
However, when the water flows into the mouth ring 47 of the impeller 44 from the water inlet 46, the liner ring 48 slightly faces the outer peripheral surface of the mouth ring 47 over the entire circumference. Since they face each other with a gap, the amount of water leaking from there is kept extremely small.

During this period, the crankshaft 32 receives an explosive load, and the reaction force due to the deflection causes the impeller 44 to
When the impeller is horizontally eccentric toward the cylinder head 49 side, the water that has entered the opposing gap escapes from the pressure relief hole 50 to the impeller accommodation chamber 38, and the bubbles that have entered this are prevented from being crushed. This will prevent cavitation from occurring.

In addition, in the above embodiment, the pressure relief hole 5
0, a case has been described in which one oval shaped hole is provided on the wall of the mouth ring 48 on the head side in the piston reciprocating direction, but the manner in which the pressure relief hole 50 is formed is not limited to this. ,
It is also possible to have a configuration in which a plurality of small holes are concentrated in one place, and it goes without saying that the design can be modified as appropriate without departing from the spirit of the present invention.

(Effects of the invention) As described above, the horizontal internal combustion engine with a water pump of the invention has a flywheel fixed to the end of the crankshaft, which is surrounded by a flywheel housing.
A pump casing of a centrifugal water pump, which is located on the outer surface of the flywheel housing and has a spiral water passage around the outer periphery of an impeller housing chamber, is integrally formed with the flywheel housing, and an impeller built in the impeller housing chamber. is connected to the flywheel mounting side end of the crankshaft, and the mouth ring outer circumferential surface of the impeller is formed at the water inlet inner end of the pump lid fitted to the outer extended opening end of the impeller housing chamber. In a horizontal internal combustion engine with a lift pump, which is surrounded by a ring with a small opposing gap around the entire circumference, the opposing gap and Since a pressure relief hole is drilled to communicate with the impeller housing chamber, when the pump is running, the crankshaft is bent due to the explosion load of the internal combustion engine, and the impeller is eccentric toward the head side in the direction of piston reciprocation due to the reaction force. Even if the water that has flowed into the opposing gap escapes from the pressure relief hole to the impeller accommodation chamber side, the bubbles of the gas mixed therein are prevented from collapsing, which has the excellent effect of preventing cavitation in this area. Demonstrate.

Moreover, according to the present invention, cavitation can be prevented by providing a pressure relief hole only in a part of the liner ring, so the facing gap between the mouth ring and the liner ring can be set as small as before, and the pump efficiency is increased. The effect of being able to maintain a high value can also be fully expected.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of a horizontal internal combustion engine with a water pump according to the present invention, Fig. 2 is a plan cross-sectional view taken in the direction of - arrow in Fig. 1, and Fig. 3 is a pump lid applicable to the engine. FIG. 4 is a schematic diagram of a lift pump set driven by a conventional internal combustion engine, and FIG. 5 is a front sectional view showing an example of the horizontal internal combustion engine with a lift pump proposed earlier. be. 32... Crankshaft, 32a... End, 35...
... flywheel, 36 ... flywheel housing, 38 ... impeller housing chamber, 39 ... spiral water passage, 40 ... centrifugal water pump, 41 ...
...Pump casing, 44... Impeller, 45...
... Pump lid, 46 ... Water inlet, 47 ... Mouth ring, 48 ... Liner ring, 49 ... Cylinder head, 50 ... Pressure relief hole.

Claims (1)

[Scope of utility model registration request] A centrifugal water pump includes a flywheel fixed to the end of a crankshaft, which is surrounded by a flywheel housing, and a spiral water passage located on the outer surface of the flywheel housing and around the outer periphery of an impeller housing chamber. A pump casing is integrally formed, and an impeller built in the impeller housing chamber is connected to the flywheel attachment side end of the crankshaft, and the outer peripheral surface of the mouth ring of the impeller is extended outside the impeller housing chamber. In a horizontal internal combustion engine with a water pump that is surrounded by a liner ring formed at the inner end of the water inlet of a pump lid fitted to the open end with a slight opposing gap around the entire circumference, A water pump, characterized in that a pressure relief hole is bored at a position on the head side in the direction of piston reciprocation of the internal combustion engine, one end of which opens into the opposing gap, and the other end of which opens into the impeller housing chamber. Horizontal internal combustion engine.