JPS60153452A - Piston for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a piston for an internal combustion engine, and more particularly to a piston used in an internal combustion engine equipped with an oil injection type piston cooling device.

BACKGROUND OF THE INVENTION In an internal combustion engine, overheating of engine parts must be avoided at all costs in order to maintain normal operation of the engine. The top wall of the piston, which is located in the cylinder bore and forms part of the wall of the combustion chamber, is exposed to relatively severe thermal conditions among other engine parts, and is subject to an increase in heat load as the engine output increases. As a result, forced cooling is becoming necessary.

As a type of piston cooling device that forcibly cools the top wall of a piston, engine lubricating oil is injected toward the piston top wall from the inner space side of the piston having a cup-shaped structure, and the engine lubricating oil cools the top wall of the piston. BACKGROUND OF THE INVENTION Oil injection type piston cooling devices that cool a wall portion are conventionally known. As a piston improved so that the top wall part is effectively cooled by the oil injection type piston cooling device as described above, the inner space of the piston body is designed to receive the lubricating oil injected toward the top wall part. A piston is equipped with a shelf-shaped oil reservoir member constituting an oil reservoir on the top wall side of the piston.
No. 96796 (Utility Publication No. 54-26424/), Utility Application No. 55-42967 (Utility Application No. 57-156052),
Patent application No. 138183/1983, Utility patent application No. 16404/1983
No. 0, Utility Model Application No. 188456/1983 has already been proposed.

Although the pistons having the oil sump component l as described above achieve the initial purpose, they still have drawbacks regarding the manufacturability of the piston, the ease of assembling the oil sump component to the piston body, and the reliability of assembly. , and there is not enough information on these.

Purpose of the Invention The present invention provides an oil reservoir component that can be attached to a piston body using a structure that does not require major changes to the piston body of general structure and is easy to assemble and has excellent assembly reliability. The purpose is to provide a piston for internal combustion engines.

"Structure of the Invention": According to the present invention, the present invention has a cup-shaped piston body having a top wall at one end, and an oil reservoir component provided in the inner space of the piston body. , the oil reservoir component includes a shelf section defining an oil reservoir section on a part of the top wall 9, and a shelf section fixedly connected to the shelf section and provided around a piston pin hole of the piston body. This is achieved by a piston for an internal combustion engine that includes a pair of leg portions that are respectively engaged with the outer peripheries of a pair of boss portions and supported by the piston body.

Effects of the Invention As mentioned above, in the piston for an internal combustion engine according to the present invention,
Since the oil reservoir component is attached to the piston body by effectively utilizing the boss portion around the piston pin hole that the piston body originally has, there is no need to make any major changes to the piston body of general structure. The oil reservoir component has a simple structure and can be securely attached to the piston body.

DESCRIPTION OF EMBODIMENTS The present invention will now be described in detail with reference to embodiments 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 and closing the one end. The back surface 3a of the top wall portion 3, ie, the ceiling surface 3a of the inner space of the piston body 1, is inclined at a slope of -[0] as it goes from the side circumference toward the center. Note that the ceiling surface 3a may be formed into a substantially hemispherical shape. A pair of boss portions 4 are formed on the inside of the peripheral wall portion 2 to bulge out toward the inner space of the piston body 1 so as to face each other. A hole 5 is provided. The piston body 1 is inserted into the piston pin hole 5.
A piston pin is inserted to connect the piston and a connecting rod (not shown).

Two piston ring grooves 6 and one oil ring groove 7 are provided on the outer periphery of the top wall 3 and the side peripheral wall 2, and the oil ring #47 passes through the slit hole 8 to the inside of the piston body 1. connected to space.

Each boss portion 4 includes a cylindrical engaging portion 9a on the outer periphery of the tip portion, which has a smaller diameter than the outer periphery of the root portion, and an annular end surface 91 located at the end of the cylindrical engaging portion on the root side. It has a stepped portion 9. The parts of the inner circumferential surface of the piston body 1 that face each other in the direction perpendicular to the axis of the piston pin hole 5, that is, the skirt parts, each have a portion of the piston body 1 from the tip edge thereof.
A relatively wide guide groove 2a is formed along the axis.

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 a shelf section 120 extending from both side edges to one side. It has a pair of bent leg sections 13 and another pair of leg sections 14 bent toward one side from both end edges of the shelf section 12, and the entire leg section 13 is made of a material such as spring steel. It is press-molded from a metal plate with appropriate elasticity. Each leg piece 13 is
A relatively small first piece 13a is bent along a first folding line A relative to the shelf board 12, and a leg is bent along a second folding line B relative to the first piece 13a. It has a relatively large second piece part 13b which forms the majority of the piece part 13, and the distance between the first 6-fold line A of the pair of leg parts 13 (-a is the distance between the pair of boss parts). 4 tip surface 48
The distance LC between the second folding lines 8 of the pair of leg portions 13 is equal to the distance L b between them, but is slightly smaller than that, and the distance LC between the second folding lines 8 of the pair of leg portions 13 is equal to the distance Ld between the annular end surfaces 9b of the stepped portions 7 of the pair of boss portions 4. The pair of leg portions 13 are approximately equal to each other, and the pair of leg portions 13 are attached in the free state as shown in FIGS. 4 and 5.
Their legs are spread apart from each other. The second pieces 13b of the leg portions 13 each have an overhanging cylindrical portion 15 formed by overhang press molding from the second piece so as to protrude toward the other leg portion, that is, toward the inside. is provided,
An engagement hole 16 is formed by the overhanging cylindrical portion, and the engagement hole is adapted to engage the cylindrical engagement portion 9a of the boss portion 4 in a circumferential manner. The tip, ie, the lower end, of the second piece 13b has a semicircular shape, and the outer diameter of the lower end is larger than the outer diameter of the tip of the boss portion 4.

The pair of leg portions 14 are adapted to engage with the guide groove 28 of the piston body 1, and in the previous free state, the pair of leg portions 14 are fitted between the tip portions as shown in FIG. Interval 1e
is the distance Lf between the bottoms of the pair of guide grooves 2a (see Figure 2)
It's a little bigger than that.

As shown in FIG. 5, the oil reservoir component 1o 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 leg pieces 13 corresponding to the boss 4. Inside the piston body 1, the pair of leg pieces 13 are elastically deformed in the direction toward each other, as shown by the imaginary lines in FIG. By being inserted into the space, it can be attached to the piston body 1 with a single touch by a spring action.

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, the maximum outer distance between the pair of leg portions 13 is the same as that of the boss portion 4.
The distance is equal to or smaller than the distance Lb between the distal end surfaces 4a, so that the pair of leg portions 13 can be easily inserted between the boss portions 4. When the oil reservoir component 1o is inserted into the inner space of the piston body 1 from the open end thereof, at the same time, the pair of leg portions 14 elastically deform and engage with the guide groove 28 to slide therein. Therefore, the oil reservoir component 10 is inserted into the piston 1 by the pair of leg portions 14 and the guide groove 2a.
This can be done reliably and easily without wobbling as a result of the engagement. A pair of leg pieces 13 are inserted between the boss parts 4,
When L16 is aligned with the cylindrical engagement portion 9a of the boss portion 4, the pair of leg portions 13 are elastically deformed in the direction away from each other due to their own spring force, and the outer surface of the second portion 13b around the hole 16 is At the same time, it is pressed against the annular end surface 9b of the boss portion 4, and at the same time, the entire inner circumferential surface of the overhanging cylindrical portion 15 is joined to the outer circumferential surface of the cylindrical engaging portion 9a. To this J: hole 16
is circumscribed to the cylindrical engaging portion 9a, and the oil reservoir component 10 is fixedly connected to the piston body 1 by its own spring action.
be done.

As can be seen from the above description, in the piston according to the present invention, the stepped portion is only provided on the outer periphery of the tip end of the boss portion, and the piston body can be attached to the oil reservoir component without making any major changes to the piston body for attaching the oil reservoir component. It will be appreciated that it can be easily and reliably attached to the piston body with just one touch and without the need for special attachment parts or attachment tools.

The rotation around the piston pin hole 5 of the oil reservoir component 1o is prevented by the pair of leg pieces 14 being pressed against the bottom of the groove 2a by their own spring force. This may be done by not forming the engaging portion 9a and the hole 16 in a perfect circle.

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

As clearly 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 hold the oil. 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.

10- As a result, as clearly shown in FIG. 3, 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. A relatively large opening 19 is provided in one side near the other end between the opening 19 and the piston body 1, one of which is used as an oil supply passage and the other as an oil discharge passage. It is now possible to do so.

Next, the behavior of the lubricating oil for cooling the piston in the piston configured as described above will be explained.

Lubricating oil for cooling the piston is injected toward the ceiling surface 3a of the piston body 1 through the opening 18 from a nozzle (not shown) fixedly disposed on the side of the crank chamber. When the piston is moving upward from the bottom dead center position to the top dead center position, the relative speed of the lubricating oil from the nozzle to the ceiling surface 3a is small, and therefore the lubricating oil injected from the nozzle is moving upward from the ceiling surface 3a. Most of the oil falls onto the shelf board part 12 of the oil sump constituting member 10 and accumulates in the oil sump recess 11 without wetting the entire oil sump 3a. When the piston is at the top dead center position -11=, the lubricating oil is accumulated in the oil sump recess 11, rises, and cools the top wall portion 3 again.

When the piston moves from the bottom dead center position to the top dead center position, most of the lubricating oil that is peeled off from the ceiling surface 3a due to the inertial action is received by the shelf part 12, but some of the lubricating oil The oil falls onto the upper surface portion 4b of the boss portion 4, and flows downward from this, that is, into the oil pan.

A portion of this lubricating oil flows along the surface of the leg portion 13 and drips from the lower end of the leg portion 13 because the lower end edge thereof protrudes below the boss portion 4 . That is, the leg portion 1
The lower end of the piston 3 performs an oil draining action, thereby preventing the lubricating oil from adhering to the inner circumferential surface of the cylinder bore that receives the piston.

Incidentally, a protruding tongue piece 13c may be formed protrudingly at the end portion in order to obtain the above-mentioned oil draining effect more clearly, and as shown in FIG. 7, the lower end portion of the leg portion 13 It may be bent toward the center side.

13- In the above, the present invention has been described with reference to specific embodiments.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an oil reservoir component of a piston for an internal combustion engine according to the present invention, FIG. 5 is an exploded view of the piston for an internal combustion engine according to the present invention, and FIGS. 6 and 7 are each according to the present invention. It is a sectional view showing other examples of a piston for internal combustion engines. 1... Piston body, 2... Surrounding wall part, 2a...
Guide groove. 3...Top wall surface, 3a...Ceiling surface, 4...Boss part,
4a...Tip part, 4b...Top part, 5...Piston pin hole, 6...Piston ring groove, 7...Oil ring groove, 8...Slit hole, 9...Step Attachment, 9a
...Cylindrical engagement part. 14-9b... Annular end surface, 10... Oil reservoir component, 11
... Oil reservoir depression, 12 ... Shelf board part, 13 ... Leg piece part, 13a ... first piece part, 13b ... second piece part, 13G ... protruding tongue piece , 14... leg piece, 15...
- Overhanging cylindrical part. 16...hole, 17...wing, 18.19...when opened Applicant: Toyota Motor Corporation Agent: Patent Attorney Masaki Akashi

Claims (1)

[Claims] It has a cup-shaped piston body having a top wall at one end, and an oil reservoir component provided in an inner space of the piston body, and the oil reservoir component has an oil reservoir on the side of the top wall. A shelf board part constituting the section, and a pair of boss parts that are fixedly connected to the fence board part and provided around the piston pin hole of the piston main body are respectively engaged with outer peripheral parts and supported by the piston main body. A piston for an internal combustion engine, comprising a pair of leg pieces.