JP2001124049A - Crankshaft holding structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crankshaft holding structure of engine capable of restricting the thrust direction moving amount of a crankshaft using a simple configuration. SOLUTION: An energizing means 60 to energize a crankshaft 11 in the thrust direction is interposed between the thrust receiving surface 34 of one bearing part 30 and a first thrust thrust receiving surface of the crankshaft 11, and energization is made so that a second thrust receiving surface 52 of the crank shaft 11 is pressed to the thrust receiving surface 44 of another bearing part 40, and thus movement in thrust direction of the crankshaft 11 is suppressed. This permits omission of adjustment of the thrust direction moving amount of the crankshaft 11 in the engine assembling process, and manufactur of engines is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine crankshaft holding structure, and more particularly to an engine crankshaft holding structure in which a crankshaft is rotatably held in a crank chamber via a bearing.

[0002]

2. Description of the Related Art FIG.
FIG. 5 is an enlarged view of a portion Y in FIG. The engine 1 used in the present embodiment is a general-purpose engine used for a portable small generator and the like. As shown in FIG. 4, the engine 1 has a cylinder block 4 in which a crankcase 2 and a cylinder 3 are integrally formed, and a cylinder head 6 provided with a valve mechanism 5 is provided above the cylinder block 4. Have been.

The crankcase 2 cooperates with a case cover 7 to form a crankcase 10 having a predetermined interior space below the engine 1, and a crankshaft 11 extends in the crankcase 10 in the left-right direction. It is rotatably supported.

The crankshaft 11 has journal portions 12 and 1 at positions corresponding to the crankcase 2 and the case cover 7.
The webs 14 and 15 are provided between the journal portions 12 and 13 so as to face each other and form a pair and extend in a direction intersecting the axial direction. Web 14,
A crank pin portion 18 for supporting a connecting rod 16 connected to a piston 17 is provided between the web members 15 and a sprocket for driving the valve train 5 between the web 14 and the journal portion 12 on the case cover 7 side. A power transmission shaft portion 20 to which the shaft 19 is attached is provided.

The left side wall 21 of the crankcase 2 is provided with a case through hole 22 through which the shaft end 11a of the crankshaft 11 is inserted. A cover through hole 23 for inserting the portion 11b is formed.

[0006] Journal receiving portions 2 are provided inside the crankcase 10 through the case through-hole 22 and the cover through-hole 23, respectively.
4 and 25 are recessed, and journal receiving portions 24 and 25 are provided.
, Bearings 30 and 40 are press-fitted and fixed respectively.

The bearings 30 and 40 are provided with outer rings 31 and 41, respectively.
And the inner rings 32 and 42 have a double ring shape, and have a structure rotatable with each other via balls 33 and 43 therebetween. The outer rings 31, 41 have outer diameters that are press-fitted into the journal receiving portions 24, 25. The inner rings 32 and 42 have an inner diameter into which the journal portion 12 of the crankshaft 11 is press-fitted, and have thrust receiving surfaces 34 and 44 inside the crank chamber 10.

The crankshaft 11 has a cover-side thrust receiving surface 51 facing the thrust receiving surface 34 of the bearing 30 on the case cover 7 side and a case facing the thrust receiving surface 44 of the bearing 40 on the crankcase side 2. A side thrust receiving surface 52 is provided.

As shown in FIG. 5, a gap 55 is formed between the thrust receiving surface 34 of the bearing 30 on the case cover 7 side and the thrust receiving surface 51 on the cover side, and a shim washer 56 is interposed. ing. Gap 55
Is formed so as to have a gap width within a predetermined range from the relationship of the manufacturing accuracy of the cylinder block 4 and the case cover 7.

FIG. 6 is a schematic view of the shim washer 56, in which (a) is a perspective view and (b) is a sectional view. The shim washer 56 has a ring shape having an inner diameter that allows the crankshaft 11 to be inserted. The plate thickness t ′ has an accuracy of the order of 1/100 mm. It regulates movement.

The gap width of the gap 55 is determined by the crankcase 2
Since it changes according to the processing accuracy of the crankshaft 11 and the case cover 7 and differs individually for each engine, it is measured using a special jig at the time of engine assembly.

Then, a shim washer 56 having a thickness corresponding to the measured value is appropriately selected and mounted so as to be interposed in the gap. Thereby, the movement of the crankshaft 11 in the thrust direction is restricted, and the generation of the thrust sound during the operation of the engine is prevented.

[0013]

However, the measurement of the gap width of the gap 55 is complicated and increases the number of manufacturing steps of the engine 1. In addition, since it is necessary to cope with various gap widths, it is necessary to always prepare a plurality of types of shim washers 56 having a high-precision thickness t 'as inventory, which complicates inventory management of parts. .

Further, the shim washer 56 is required to have a plate thickness accuracy in units of 1/100 mm. However, there is a possibility that an erroneous assembly in which an erroneous size is assembled during engine assembly may occur.

On the other hand, Japanese Patent Application Laid-Open No. 60-179597 discloses a technique in which an elastic material is provided between a rolling bearing and a crankcase cover to restrict the movement of the crankshaft in the thrust direction. According to this, the rolling bearing itself is moved in the thrust direction by the elastic material, and the rolling bearing is brought into contact with the crankshaft with a predetermined pressing force to regulate the movement of the crankshaft in the thrust direction.

However, since the rolling bearing supports the crankshaft rotating at high speed, it is not preferable to move its position.

Further, since it is necessary to move the rolling bearing while holding it in the crankcase, it is necessary to provide an insert for inserting the bearing in the crankcase. Therefore, the structure becomes complicated, and the manufacturing cost increases due to the increase in the number of parts and the accompanying increase in the number of manufacturing steps.

The present invention has been made in view of the above-mentioned problems, and has as its object to provide a crankshaft holding structure for an engine capable of restricting the movement of the crankshaft in the thrust direction with a simpler configuration. Is to do.

[0019]

In order to solve the above-mentioned problems, a crankshaft holding structure for an engine according to the present invention is provided so as to face each other at positions spaced apart from each other in a crank chamber of the engine. Bearing portion having a thrust receiving surface, a first thrust receiving surface which is mounted between the bearing portions and faces a thrust receiving surface of one bearing portion, and a second thrust receiving surface which faces a thrust receiving surface of the other bearing portion. So that the second thrust receiving surface is interposed between the thrust receiving surface of the one bearing portion and the first thrust receiving surface so that the second thrust receiving surface is pressed against the thrust receiving surface of the other bearing portion. Biasing means for biasing the crankshaft in the thrust direction;
It is characterized by having.

According to this, the crankshaft is urged to one side in the thrust direction such that the second thrust receiving surface is pressed against the thrust receiving surface of the other bearing portion, and the movement in the thrust direction is performed. Be regulated.

Therefore, in the case of the shim washer, it is necessary to regulate the range of movement of the crankshaft in the thrust direction. The thrust receiving surface of one bearing and the first thrust surface of the crankshaft are required. It is possible to omit the measurement of the gap width formed between them and the selection of a shim washer having a thickness corresponding to the measured value.

Further, since it is not necessary to prepare shims washers having different thicknesses at the time of assembling, inventory management of parts and the like can be simplified. Further, there is no possibility of wrong assembly of a wrong size such as a shim washer. Therefore, the manufacturing cost can be reduced and the manufacturing can be facilitated by reducing the number of assembly steps.

According to a second aspect of the present invention, there is provided a wave washer in which the urging means has a washer shape through which a crankshaft can be inserted, and is formed into a wave shape so as to have a spring action in its thickness direction. It is characterized by. According to this, the urging in the thrust direction of the crankshaft can be reliably performed with a simple configuration.

[0024]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of the engine, and FIG. 2 is an enlarged view of a portion X in FIG. Note that the same components as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted. A feature of the present embodiment is that a wave washer 60 is used in place of the shim washer 56 described in the related art.

FIGS. 3A and 3B are schematic views of the wave washer 60. FIG. 3A is an overall perspective view, and FIG. 3B is a sectional view of FIG. The wave washer 60 is formed of an elastic member such as a thin steel plate, has a thin plate shape with a thickness t, has an outer diameter substantially the same as the inner ring 32 of the bearing 30, and has a crankshaft 1.
It has an inside diameter into which one journal portion 12 can be inserted.

Then, as shown in FIG.
The portions 60a and 60b opposed to each other with 1 therebetween are curvedly formed in a waveform so as to be spaced apart from the adjacent portions 60c and 60d in the thickness direction, and have a spring action in the thickness direction. Further, as shown in (b) in the figure, the non-compressed state has a compressed width (Tt) in the thickness direction.

As shown in FIGS. 1 and 2, the wave washer 60 is mounted in a gap 55 between the thrust receiving surface 34 of the bearing 30 on the case cover 7 side and the cover-side thrust receiving surface 51 of the crankshaft 11. Is done. The gap width T 'of the gap portion 55 has an interval in a range larger than the plate thickness t of the wave washer 60 and smaller than the uncompressed height width T of the wave washer 60 (t <T'<T).

Therefore, as shown in FIG. 2, in the wave washer 60, the portions (60c and 60d in the figure) of the gap 55 that protrude in one thrust direction are in contact with the cover-side thrust receiving surface 51 of the crankshaft 11. The parts protruding in the thrust direction in contact with and separated from this (60a, 6
0b) comes into contact with the thrust receiving surface 34 of the bearing 30 on the case cover 7 side, and is compressed and contracted in the thrust direction so that its curvature is extended.

As a result, the thrust receiving surface 34 of the bearing 30 on the case cover 7 side and the thrust receiving surface 51 on the cover side
And the crankshaft 11 is urged in the thrust direction on the crankcase 2 side (the direction of arrow F in the figure).

Therefore, as shown in FIG. 1, the case-side thrust receiving surface 52 of the crankshaft 11 is
The thrust receiving surface 44 of the bearing 40 is pressed with a predetermined pressing force. Therefore, the crankshaft 11
It is held in the crank chamber 10 in a stable state in which the movement in the thrust direction is suppressed.

Therefore, in addition to the function and effect of preventing backlash in the thrust direction of the crankshaft 11 and the generation of thrust noise due to this, in the case of a shim washer, the range of movement of the crankshaft in the thrust direction is restricted. The measurement of the gap width of the gap portion 55 and the selection of the shim washer 56 according to the measured value, which are operations required for the above, can be omitted.

Further, since one kind of wave washer 60 can cope with various gap widths, it is not necessary to prepare shim washers 56 having various thicknesses in advance, which simplifies parts inventory management and the like. And there is no risk of erroneous assembling of a wrong size such as a shim washer.

Further, the gap width T 'of the gap portion 55 is
If the thickness is larger than the thickness t of the wave washer 60 and smaller than the height T of the wave washer 60, the crankshaft 11 can be securely urged in the thrust direction. Processing accuracy can be reduced. Therefore, the engine can be easily manufactured, and the manufacturing cost can be reduced.

Note that the present invention is not limited to the above-described embodiment, and various changes can be made within the gist of the present invention. For example, in the above-described embodiment, a wave washer was used as an example of the urging means. However, the urging means is provided between the thrust surface of one bearing and the thrust receiving surface of the crankshaft, and can urge the crankshaft in the thrust direction. Anything should do. For example, the crankshaft may be urged in the thrust direction by holding a material having the same shape as the shim washer and having high elasticity itself in the gap.

Further, in the above-described embodiment, an example has been described in which the cover-side thrust receiving surface 51 corresponds to the first thrust receiving surface and the case-side thrust receiving surface 52 corresponds to the second thrust receiving surface. Moves the cover-side thrust receiving surface 51 to the second position.
A gap 55 is formed between the case-side thrust receiving surface 52 and the thrust receiving surface 44 of the bearing 40 on the crankcase 2 side so that the case-side thrust receiving surface 52 corresponds to the first thrust receiving surface. Provided, wave washer 6
0 may be interposed.

[0036]

As described above, according to the crankshaft holding structure for the engine according to the present invention, the urging means for urging the crankshaft in the thrust direction is provided between the thrust receiving surface of one bearing portion and the crankshaft. Interposed between the first thrust receiving surface and the second thrust receiving surface of the crankshaft is urged to be pressed against the thrust receiving surface of the other bearing portion,
Since the movement of the crankshaft in the thrust direction is suppressed, adjustment of the movement amount of the crankshaft in the thrust direction at the time of assembling the engine can be omitted, and the engine can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine.

FIG. 2 is an enlarged view of a portion X in FIG.

FIG. 3 is a schematic view of a wave washer.

FIG. 4 is an explanatory longitudinal sectional view of the engine.

FIG. 5 is an enlarged view of a Y part in FIG. 4;

FIG. 6 is a schematic diagram of a shim washer.

[Explanation of symbols]

 Reference Signs List 1 engine 10 crankcase 30, 40 bearing (bearing part) 34, 44 thrust receiving surface of bearing 51 cover-side thrust receiving surface (first thrust receiving surface) 52 case-side thrust receiving surface (second thrust receiving surface) 60 wave washer (Biasing means)

Claims (2)

[Claims] 1. A bearing portion which is disposed opposite to each other in a crank chamber of an engine and has a thrust receiving surface on a side surface facing each other, and is axially suspended between the bearing portions, and is provided on a thrust receiving surface of one of the bearing portions. A crankshaft having an opposing first thrust receiving surface and a second thrust receiving surface opposing the thrust receiving surface of the other bearing portion; and between the thrust receiving surface of the one bearing portion and the first thrust receiving surface. Biasing means interposed and biasing the crankshaft in the thrust direction such that the second thrust receiving surface is pressed against the thrust receiving surface of the other bearing portion;
A crankshaft holding structure for an engine, comprising: 2. The device according to claim 1, wherein said urging means is a wave washer having a washer shape through which a crankshaft can be inserted, and having a wave-shaped curve so as to have a spring action in a thickness direction thereof. The crankshaft holding structure for an engine according to claim 1.