JPH0322536Y2 - - 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 (Recently published in 1988)
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 facing the inner surface of the top wall of the piston and providing 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, its both ends are fitted into grooves cut into the inner circumferential surface of the piston peripheral wall, or are shaped like a shelf plate. The central portion of the member is held in place by being sandwiched between the central portion of the piston top wall and the opposite end of the connecting rod.

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. Insert the end of the connecting rod between the pair of legs of the oil sump component, align the three holes of the piston body, the oil sump component, and the piston rod, and insert it there. It is necessary to pass the piston 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 providing an oil reservoir recess facing the inner surface of the top wall portion, and a pair of shelf plates bent from both side edges of the shelf plate portion. and a pair of abutting pieces bent from both ends of the shelf plate, the oil sump configuring member having the pair of leg pieces attached to it. The opening engages with a cylindrical engaging part whose diameter is reduced in steps around the inner end of the boss part through the opened engaging hole, and the pair of leg pieces try to open in the direction in which they separate from each other. Due to the elastic force of The internal combustion engine is characterized in that the contact piece portion is attached to the piston body by engaging and being guided by a pair of guide grooves provided on the inner peripheral surface of the peripheral wall portion of the piston body. Achieved by engine pistons.

[Operation of the device] As described above, the shelf plate portion and the shelf plate portion are provided in the inner space of the cup-shaped piston body that has a top wall portion, a peripheral wall portion, and a pair of boss portions that protrude inwardly facing each other. An oil reservoir component having a pair of leg pieces bent from both side edges of the piston body is shaped like a step around the inner end of the boss part of the piston body through the engagement hole formed in the pair of leg pieces. A piston for an internal combustion engine configured to engage with a cylindrical engaging portion whose diameter is reduced and to be held in the engaged position by elastic force that causes a pair of leg portions to open in a direction away from each other. In this case, the oil reservoir component is further provided with a pair of abutting pieces bent from both ends of the shelf plate, and these pair of abutting pieces touch the inner circumferential surface of the peripheral wall of the piston body. Since the oil reservoir component is engaged with and guided by a pair of guide grooves provided in the piston body, the oil reservoir component is not attached to the piston body during the process of installing the oil reservoir component into the piston body. The piston body can be easily guided to the correct posture, and after the oil reservoir component is installed in the piston body, the oil reservoir component can stably maintain the correct mounting position of the oil reservoir component with respect to the piston body.

[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 peripheral wall portion 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. On the inner circumferential surface of the piston body 1, the parts facing each other in the direction orthogonal to the axis of the piston pin hole 5, that is, the skirt parts, each have a relatively wide guide groove extending from the tip end thereof along the axis of the piston body 1. 2a is formed. The guide groove 2a may be formed by casting the piston body 1, or may be formed by effectively utilizing a step in a mold dividing part of a casting mold.

As shown better in FIGS. 4 and 5, the oil sump component 10 includes a substantially rectangular shelf section 12 having an oil sump recess 11, and a substantially rectangular shelf section 12 extending from both side edges of the shelf section to one side. A pair of bent leg pieces 1
3 and a pair of abutting pieces 14 bent toward one side from both ends of the shelf plate 12, and the whole is press-formed from a metal plate having appropriate elasticity such as spring steel. There is. Each leg piece 13 is a shelf part 1
2, a relatively small first piece 13a is bent along a first folding line A, and a leg piece 13 is bent along a second folding line B relative to the first piece 13a. The first folding line A of the pair of leg pieces 13
The spacing La between the two is equal to or slightly smaller than the spacing Lb between the tip surfaces 4a of the pair of boss portions 4, and the spacing Lc between the second folding lines B of the pair of leg portions 13 is equal to or slightly smaller than the spacing Lb between the tip surfaces 4a of the pair of boss portions 4. Distance between annular end surfaces 9b of stepped portion 9
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. An engagement hole 16 is formed in each second piece 13b of the leg part 13 by an overhanging cylindrical part 15 formed to protrude from the second piece part toward the other leg part by press molding. The engagement hole is adapted to be externally engaged with the cylindrical engagement portion 9a of the boss portion 4.

The pair of abutment pieces 14 are adapted to engage with the guide groove 2a of the piston body 1, and in the free state before installation, there is a gap between the tips of the two abutment pieces 14, as shown in FIG. The distance Le is slightly larger than the distance Lf between the bottoms of the pair of guide grooves 2a (see FIG. 2).

As shown in FIG. 5, the oil reservoir component 10 has a shelf plate portion 12 located on the side closer to the piston body 1, a pair of leg portions 13 corresponding to the boss portion 4, and a pair of abutting portions. With the piece 14 in the orientation corresponding to the groove 2a, the pair of leg pieces 13 are elastically deformed in a direction toward each other as shown by imaginary lines in FIG.
The pair of abutment pieces 14 engage with the guide grooves 2a and are inserted into the inner space of the piston body 1 while being guided by the guide grooves 2a, so that they can be attached to the piston body 1 with a single touch by a spring action. It will be done.

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 oil reservoir component 10, at the same time, the pair of abutment pieces 14 engage with the guide groove 2a while being elastically deformed and slide in the guide groove. The insertion into the piston 1 is guided by the engagement between the pair of abutment pieces 14 and the guide groove 2a, and is carried out reliably and easily without wobbling. A pair of leg pieces 13 are inserted between the boss parts 4,
When the engagement hole 16 is aligned with the cylindrical engagement portion 9a of the boss portion 4, the pair of leg portions 13 are elastically deformed in a direction away from each other due to their own spring force, and the legs around the engagement hole 16 are The outer surface of the second piece 13b is pressed against the annular end surface 9b of the boss portion 4, and the inner circumferential surface of the overhanging cylindrical portion 15 is joined to the outer circumferential surface of the cylindrical engaging portion 9a over its entire surface. In this way, the oil reservoir component 10 is securely attached to the piston body 1 by its own spring action.

When the oil reservoir component 10 is fixed in the inner space of the piston body 1 in the above manner, the shelf plate portion 12 extends along a plane (horizontal plane) perpendicular to the axis of the piston body 1, and the top wall An oil reservoir portion is formed by an oil reservoir depression 11 near the portion 3.

As better 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 near both ends thereof. These wings function to catch oil, and are 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 between the piston body 1 and the other side of the oil reservoir component 10 in the vicinity of the one end.
Further, a relatively large opening 19 is provided on one side near the other end between the piston body 1 and the piston body 1.
One of them is used as an oil supply passage, and the other is used as an oil discharge passage.

[Effect of the invention] According to the structure of the invention as described above, the pair of contact pieces of the oil reservoir component engage with the pair of guide grooves provided on the inner surface of the peripheral wall of the piston body. is guided to a predetermined installation position with respect to the piston body, and when the pair of leg pieces reaches the installation position, the pair of leg pieces engage the engagement holes provided therein by their own elastic force, and engage the pair of boss parts located there. By being fitted into the surrounding cylindrical engaging portion, the oil sump engaging member is immediately brought into its predetermined final installed state.

[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 - in FIG. 1, and FIG. 3 is a sectional view along the line -
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. DESCRIPTION OF SYMBOLS 1... Piston body, 2... Peripheral wall part, 2a... Guide groove, 3... Top wall part, 4... Boss part, 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 pool component, 11... Oil pool depression, 12... Shelf board part, 13... Mounting leg piece part, 13a... First piece part, 1
3b...Second piece, 14...Mounting guide leg piece, 15
... Overhanging cylindrical part, 16... Engagement hole, 17... Wing part, 1
8, 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. A shelf board portion facing the inner surface of the top wall portion and providing an oil reservoir recess, a pair of leg pieces bent from both side edges of the shelf board portion, and a pair of leg pieces bent from both end edges of the shelf board portion. an oil reservoir component having an abutment piece portion, and the oil reservoir component has a step-like shape around the inner end of the boss portion in which the pair of leg portions are provided with engagement holes formed therein. The engaging hole of the leg portion engages with the cylindrical engaging portion of the boss portion due to the elastic force that causes the pair of leg portions to open in the direction of separating from each other. The pair of abutting pieces are provided on the inner circumferential surface of the peripheral wall of the piston body when the piston body is maintained in an engaged state with the shaped engagement portion and inserted into the inner space of the piston body. A piston for an internal combustion engine, characterized in that the piston is attached to the piston body by being engaged and guided by a pair of guide grooves.