JPH048288Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a piston for an internal combustion engine, and particularly to a piston used in an internal combustion engine equipped with an oil injection type piston cooling device.

[Prior Art] As the output of internal combustion engines increases, the top wall of the piston, which is located inside the cylinder bore and forms part of the wall of the combustion chamber, is exposed to a severe thermal load and requires forced cooling. It's coming.

As a piston cooling device that forcibly cools the top wall of the piston, engine lubricating oil is injected from the inner space of the piston body having a cup-like structure toward the top wall of the piston, and the engine lubricating oil cools the piston. An oil injection piston cooling device that cools the top wall has already been proposed, and in order to more effectively cool the piston top wall with such an oil injection piston cooling device, a In order to temporarily catch the injected lubricating oil and spray it again toward the top wall of the piston as the piston reciprocates,
It is known in Japanese Utility Model Publication No. 54-26424 and the earlier Utility Model Application No. 1983-1983 to install a shelf-shaped oil reservoir member forming an oil reservoir in the inner space of the piston body, facing the inner surface of the top wall of the piston. No. 185184 (Actual Publication No. 18518-
90055).

As described above, by inserting the shelf plate-shaped oil reservoir constituent member into the inner space of the piston body and configuring the oil reservoir facing the top wall of the piston body, the oil injection device can spray the top wall of the piston body The lubricating oil injected toward the inner surface of the top wall once cools down and is then received by the oil reservoir, and when the piston reaches its top dead center again, the inertial force acting on the oil causes the piston to reflow. The lubricating oil is sprayed onto the inner surface of the top wall, and better cooling of the piston top wall is achieved by respraying or respraying the lubricating oil.

In the above-mentioned Japanese Utility Model Publication No. 54-26424, the oil reservoir component consists only of a shelf-like member that faces the inner surface of the piston top wall and provides an oil reservoir, and is located within the inner space of the cup-shaped piston body. When the piston is brought to a predetermined position and has a predetermined attitude relative to the piston body, both ends thereof are fitted into grooves cut into the inner peripheral surface of the piston peripheral wall, or
Alternatively, the central part of the shelf-like member is held between the central part of the piston top wall and the opposite end of the connecting rod, so that it can be mounted in that position.

Furthermore, in the above-mentioned Utility Model Application No. 185184/1984, the oil sump component has a shelf and a pair of legs bent from both side edges of the shelf, and the oil sump component is connected to the piston. When installing the oil sump component at a predetermined position within the main body, insert the oil reservoir component into the inner space of the piston body so that the holes formed in the pair of legs align with the piston pin holes formed in the piston body. Hold the connecting rod, then insert the end of the connecting rod between the pair of legs of the oil sump component, align the three holes in the piston body, the oil sump component, and the piston rod, and insert the piston there. It is necessary to pass the pin through.

[Problems to be solved by the invention] In any of these cases, when attaching the oil reservoir component to the piston body, it is necessary to bring the oil reservoir component to the correct mounting position with respect to the piston body in advance, and to adjust the oil reservoir configuration in advance. It is believed that it is necessary to hold the member in position for a period of time, and that some assembly holding means is required for this purpose, and that its operation requires delicate movements.

The present invention provides an oil sump component that is inserted into the inner space of a cup-shaped piston body and forms an oil sump facing the inner surface of the top wall of the piston body. An object of the present invention is to provide a piston for an internal combustion engine that has an oil reservoir component and its mounting structure that can be easily and reliably mounted without requiring any means.

[Means for Solving the Problems] According to the present invention, the problem is solved by the present invention, which includes a top wall portion, a peripheral wall portion, and a pair of boss portions that protrude inwardly facing each other, and a piston pin hole is formed in the boss portions. A piston body having an open space, a shelf plate portion inserted into the inner space of the piston body and forming an oil reservoir recess facing the inner surface of the top wall portion, and a shelf plate portion bent from both side edges of the shelf plate portion. an oil reservoir component having a pair of leg portions, and the oil reservoir component has an engaging hole formed in the pair of leg portions and bordered by a cylindrical portion inside the boss portion. The engagement hole of the leg part is engaged with the cylindrical engagement part whose diameter is reduced in steps around the end, and the engagement hole of the leg part is opened by the elastic force that causes the pair of leg parts to open in the direction of separating from each other. The boss portion is kept engaged with the cylindrical engaging portion, and the leg portion has a bent portion along a side edge of the shelf portion and the engaging hole. Since the leg portions are bent along folding lines substantially parallel to the folding lines for the side edges of the shelf portion, the leg portions can be bent at one time to fold the shelf portion. Achieved by a piston for an internal combustion engine, characterized in that the length from the edge of the engagement hole to the side edge of the shelf section is substantially increased compared to the case where the piston extends to the side edge. be done.

[Operation of the invention] As described above, the oil reservoir component that provides the oil reservoir recesses facing each other on the inner surface of the top wall of the piston body is formed by a shelf board and a pair of leg pieces bent from both side edges of the shelf board. This is a cylinder whose diameter is reduced in steps around the inner ends of a pair of bosses in which the holes formed in the pair of legs protrude inwardly from the peripheral wall of the piston body. By assembling the oil reservoir component into the piston body so as to engage with the shaped engagement portion, the oil reservoir component can be reliably attached directly to the piston body by itself without relying on a piston pin or connecting rod. .

In this case, since the engagement hole for the piston boss is bordered by the cylindrical portion, the pair of leg pieces is a member that is quite rigid against bending in its main portion including the engagement hole. Therefore, the elastic deformation part for elastically joining the pair of leg parts to the shelf part must be provided by the part extending from the edge of the engagement hole to the side edge of the shelf part. First, the longer this portion is, the more elasticity the pair of leg portions join to the shelf portion. In this regard, as mentioned above, between the bending part along the side edge of the shelf part and the part where the engagement hole is formed, the leg part is substantially parallel to the bending line along the side edge of the shelf part. By being bent again along the folding line, compared to the case where the leg part is connected to the side edge of the shelf part by one bending,
The length from the edge of the engagement hole to the side edge of the shelf board section is substantially increased, and the elasticity of the pair of leg sections to the shelf board section is improved, and the oil reservoir component is connected to the piston. This makes it easier to install, and the stability after installation is also improved.

Furthermore, since each of the pair of leg pieces is bent twice relative to the shelf board, the whole is bent approximately 90 degrees, so the bent portion is smaller than when the legs are bent 90 degrees in one bend. The degree of stress concentration occurring in the structure is low, and a favorable effect can be obtained from the viewpoint of the strength of the member.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show one embodiment of a piston for an internal combustion engine according to the present invention. The piston for an internal combustion engine according to the present invention is composed of a piston body 1 and an oil reservoir forming member 10.

The piston body 1 is cast into a cup shape having a cylindrical peripheral wall part 2 and a top wall part 3 provided at one end of the peripheral wall part so as to close the one end. A pair of boss portions 4 are formed on the inside of the peripheral wall portion 2 to face each other and bulge toward the inner space of the piston body 1, and each of the pair of boss portions 4 is provided with a piston pin hole on the same axis. 5 is provided. A piston pin that connects the piston body 1 to a connecting rod (not shown) is inserted into the piston pin hole 5. Top wall part 3
Two piston ring grooves 6 and one oil ring groove 7 are provided on the outer periphery of the side peripheral wall 2, and the oil ring groove 7 communicates with the inner space of the piston body 1 through a slit hole 8. .

Each of the boss parts 4 has a stepped part on the outer periphery of the tip part, which consists of a cylindrical engaging part 9a having a smaller diameter than the outer periphery of the root part, and an annular end surface 9b located at the end of the cylindrical engaging part on the root side. It has 9. Relatively wide grooves 2a are formed along the axis of the piston body 1 from the tip edges of the inner circumferential surface of the piston body 1 in the skirt portions, which are opposed to each other in the direction perpendicular to the axis of the piston hole 5. It is formed.

As clearly shown in FIGS. 4 and 5, the oil reservoir component 10 includes a substantially rectangular shelf section 12 having an oil reservoir recess 11, and one side from both side edges of the shelf section 12. A pair of leg pieces 13 bent to
and a pair of engaging pieces 14 bent toward one side from both end edges of the shelf plate 12, and the entirety is press-formed from a metal plate having appropriate elasticity such as spring steel. There is. Each of the leg sections 13 includes a relatively small first section 13a bent along a first folding line A relative to the shelf section 12, and a first section 13a.
The leg piece 13 is bent along the second folding line B.
The distance La between the first folding lines A of the pair of leg portions 13 is equal to the distance La between the tip surfaces 4a of the pair of boss portions 4. The distance Lc between the second folding lines B of the pair of leg portions 13 is equal to or slightly smaller than the distance Lb, and the distance Lc between the second folding lines B of the pair of leg portions 13 is the distance between the annular end surfaces 9b of the stepped portions 9 of the pair of boss portions 4.
It is almost equal to Ld, and the pair of leg pieces 13
In the free state before installation, the legs are spread apart toward each other as shown in FIGS. 4 and 5. The second pieces 13b of the leg portions 13 are engaged with each other by overhanging cylindrical portions 15 which are formed to protrude toward the other leg portion, that is, toward the inside, by press-molding the second piece with an overhang. Matching hole 1
6 is formed, and the engagement hole is adapted to be externally engaged with the cylindrical engagement portion 9a of the boss portion 4.

The pair of engagement pieces 14 are grooves 2a of the piston body 1.
In the free state before installation, as shown in FIG. 4, the distance Le between the tips is equal to the distance between the bottoms of the pair of grooves 2a.
It is slightly larger than Lf (see Figure 2).

As shown in FIG. 5, the oil reservoir component 10 has a shelf plate 12 located on the side closer to the piston body 1, a pair of leg pieces 13 corresponding to the boss 4, and a pair of engaging Inside the piston body 1, the piece 14 is in a posture corresponding to the groove 2a and the pair of leg pieces 13 are elastically deformed in the direction toward each other as shown by the imaginary line in FIG. By being inserted into the space, it can be attached to the piston body 1 with a single touch due to the spring action.

In this case, the second piece 13b is connected to the engagement hole 16.
The stepped cylindrical engaging portion 9a of the boss portion 4 at
and when removed from this engaged state for disassembly, the second piece 13b keeps its surface perpendicular to the central axis of the cylindrical engaging part 9a as much as possible. It is preferable that the leg section 13 be moved in the direction along the bending line B, but this means that the leg section 13 is bent along the folding line B so that the second section 13b can be moved in the direction of rotation. This is achieved by deviating the curve A laterally from the plane of the second piece 13b.

When the pair of leg portions 13 are elastically deformed in the direction toward each other as described above, the leg portions 13 are elastically bent along each of the first folding line A and the second folding line B. By doing so, a pair of leg pieces 1
3 is equal to or smaller than the distance Lb between the tip surfaces 4a of the boss portions 4, so that the pair of leg portions 13 can be inserted between the boss portions 4 without difficulty. The oil reservoir component 10 is the piston body 1
When inserted into the inner space from the open end of the groove 2, the pair of leg portions 14 are simultaneously elastically deformed and inserted into the groove 2.
By engaging with the groove 2a and sliding through the groove, the oil reservoir component 10 can be inserted into the piston 1 reliably and easily without wobbling as it is guided by the engagement between the pair of legs 14 and the groove 2a. It will be done. When the pair of leg parts 13 are inserted into the boss part 4 and the engagement hole 16 is aligned with the cylindrical engagement part 9a of the boss part 4, the pair of leg parts 13 are moved away from each other by their own spring force. The second piece 1 around the engagement hole 16 is elastically deformed in the direction
3b is pressed against the annular end surface 9b of the boss portion 4, and at the same time, the entire inner peripheral surface of the overhanging cylindrical portion 15 is joined to the outer peripheral surface of the cylindrical engaging portion 9a. As a result, the engagement hole 16 is connected to the cylindrical engagement portion 9.
The oil reservoir forming member 10 is fixedly connected to the piston body 1 by its own spring action.

As can be seen from the above description, in the piston according to the present invention, the stepped portion is only provided at the tip of the boss portion, and the oil reservoir component can be installed without major changes to the piston body. Easily and reliably attaches to the piston body with one touch and without the need for special mounting parts or tools.
Moreover, it will be understood that it can be installed with high reliability.

When the oil reservoir component 10 is fixed in the inner space of the piston body 1 as described above, the shelf plate portion 12 is a plane (horizontal plane) perpendicular to the axis of the piston body 1.
An oil sump depression 1 is provided near the top wall 3.
1 constitutes an oil reservoir.

As shown in FIGS. 3 and 4, the shelf portion 12 of the oil reservoir component 10 has wing portions 17 extending from the side edges in the vicinity of both ends, and the wing portions are designed to prevent oil from flowing. It acts to receive the water, and is provided only on one side near one end, and only on the other side near the other end. As a result, a relatively large opening 18 is formed on the other side of the oil reservoir component 10 near the one end, and a relatively large opening 18 is formed between the piston body 1 and the other side near the other end. A relatively large opening 19 is provided between the piston body 1 and the piston body 1, one of which is used as an oil supply passage and the other as an oil discharge passage.

[Effect of the invention] As mentioned above, in addition to the fact that the leg part is bent along the folding line A at the joint part with the shelf part,
a second piece 13 having the folding line A and the engagement hole 16;
By being bent along the folding line B between B and B, when the leg plate part is connected to the shelf part at only one bending part, as in the above-mentioned Utility Application No. 185184/1984, In comparison, the first piece 13a is highly elastic.
The second piece 13b, which is the main part of the leg part and is made substantially rigid by the overhanging cylindrical part 15, has a sufficiently high elasticity with respect to the shelf part. The legs can be opened or closed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of a piston for an internal combustion engine according to the present invention, FIG. 2 is a sectional view taken along the line - of FIG. 1, and FIG. 3 is a sectional view taken along the line - of FIG.
4 is a perspective view of an oil reservoir component incorporated in the piston for an internal combustion engine according to the present invention shown in FIGS. 1 to 3, and FIG. 5 is a cross-sectional view of the piston for an internal combustion engine according to the present invention. FIG. 1... Piston body, 2... Surrounding wall portion, 2a...
Groove, 3... Top wall portion, 4... Boss portion, 4a... Tip surface, 5... Piston pin hole, 6... Piston ring groove, 7... Oil ring groove, 8... Slit hole, 9... ...Stepped part, 9a...Cylindrical engagement part, 9b
...Annular end surface, 10...Oil reservoir component, 11...
...Oil sump depression, 12... Shelf board part, 13... Leg piece part, 13a... First piece part, 13b... Second piece part, 14... Leg piece part, 15... Extended cylindrical part ,1
6...hole, 17...wing section, 18, 19...opening.

Claims (1)

[Scope of utility model registration request] A piston body having a top wall portion, a peripheral wall portion, and a pair of boss portions protruding inwardly facing each other, the boss portions having a piston pin hole, and a piston body inserted into the inner space of the piston body. an oil sump constituting member comprising a shelf plate section providing an oil sump recess facing the inner surface of the top wall section and a pair of leg pieces bent from both side edges of the shelf section; In the oil reservoir component, the pair of leg portions are engaged with a cylindrical engagement portion whose diameter is reduced in steps around the inner end of the boss portion through engagement holes formed therein and bordered by a cylindrical portion. Further, the engagement hole of the leg portion is maintained in a state of being engaged with the cylindrical engagement portion of the boss portion due to the elastic force that causes the pair of leg portions to open in a direction in which they separate from each other. The leg portion is formed between a bent portion along the side edge of the shelf portion and a portion where the engagement hole is formed, and the leg portion is substantially in contact with the bent portion along the side edge of the shelf portion. By being bent along a folding line parallel to , the shelf board is closer to the edge of the engagement hole than in the case where the leg part is connected to the side edge of the shelf board part by one bending. A piston for an internal combustion engine, characterized in that the length of the piston up to the side edge of the piston is substantially increased.