JP3223294B2 - Piston pin fixing device for aluminum alloy piston of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for fixing a piston pin to an aluminum alloy piston of an internal combustion engine.

[0002]

[Premise Configuration] The present invention is directed to one having the following premise configuration as shown in FIG. 1 or FIG. [Premise configuration] Piston pin on aluminum alloy piston (1)
The pin ends (2a) and (2a) of (2) are fixed via screw type fixing means (3). The screw shaft insertion holes (4) and (4) are passed through the pin ends (2a) and (2a) of the piston pin (2), and the screw type fixing means (3)
The leg screw portions (5a) and (5a) of the pair of screw shafts (5) and (5) are passed through the screw shaft insertion holes (4) and (4).

First, the piston (2) is made of an aluminum alloy and is light, so that vibrations and slap noise of the engine are small, which is advantageous for high rotation and high output of the engine. Next, since the thickness of the ring land portion (11) and the skirt portion (12) of the piston (1) can be made substantially uniform along the circumferential direction, thermal distortion of the piston (1) is small, and the amount of blow-by gas is reduced. Less.

[0004]

2. Description of the Related Art In the above-mentioned premise structure, there is a prior art, for example, shown in FIG. 3 as a structure of a portion for fixing a piston pin (2) to a piston (1), which is as follows.

The screw type fixing means (3) comprises a pair of hexagonal head bolts (51) (51). Crown of piston (1)
A pair of left and right bosses (52) (52) protrudes downward from (9).
The pin bearings (53) and (53) and the screw holes (5
4) (54) is formed. The left and right pin ends (2a) and (2a) of the piston pin (2) are brought into contact with the respective pin seats (53) and (53), and the bolts (51) and (51) are connected to the respective pins of the piston pin (2). End (2a) (2a)
Through the screw shaft insertion holes (4) and (4) from below
(54) The pin ends (2a) (2a) are pressed and fixed to the pin receiving seats (53) (53) by being screwed into (54).

[0006]

The above prior art has the following problems. (I). First, the bolt (51) tends to loosen early. First, the thermal expansion coefficient of the aluminum alloy boss (52) screwed to the bolt (51) is much larger than that of the iron-based material bolt (51). For this reason, the piston (1)
When the temperature rises, the size of the boss (52) pulling up the bolt (51) increases, and the head (51a) of the bolt (51) and the pin seat (5)
3) and the tightening force of the bolt (51) increases. Next, since the thread of the screw hole (54) screwed with the bolt (51) is made of aluminum alloy and has low mechanical strength, it is easily deformed by the strong tightening force of the bolt (51).

Since the pin seat (53) is also made of an aluminum alloy, it is easily deformed by the strong tightening force of the bolt (51). Thus, the combination of the increased tightening force of the bolt (51) and the fact that the thread of the screw hole (54) and the pin seat (53) have low mechanical strength and are easily compressed and deformed, (51)
Is easy to loosen early and has poor durability.

(B). It takes time to assemble the piston pin (2). The procedure for assembling the piston pin (2) to the piston (1) is as follows:
With the skirt (12) of the piston (1) facing upward and the connecting rod (55) fitted in advance on the piston pin (2), the pin end (2a) is placed on the pin receiving seat (53), and the bolt ( 51) is inserted into the screw shaft insertion hole (4), screwed into the screw hole (54), and tightened.

At this time, the screw hole (54) is inserted into the piston pin (2).
The bolt (51) must be groped and screwed into the screw hole (54), making it difficult to fit the bolt (51) into the screw hole (54). Difficult and time-consuming. It is an object of the present invention to (a) prevent a screw for fixing a piston pin from being loosened at an early stage, and (b) to facilitate a work of assembling a piston pin.

[0010]

According to the present invention, in order to solve the above-mentioned problems in the above-mentioned premise, for example, as shown in FIG. 1, a portion for fixing a piston pin (2) to a piston (1) is provided. As a configuration, the following characteristic configuration is added. The screw type fixing means (3) includes a connecting body (6), a pair of screw shafts (5) (5) made of an iron-based material, and a pair of nuts (7) (7) made of an iron-based material. A pair of screw shafts (5) and (5) are fixedly extended to both sides of the connecting body (6). A pin seat made of iron-based material is provided in the middle of the length direction of each screw shaft (5) (5).
(8) Fix (8). The connecting body (6) is fixed to the inside of the wall of the crown (9) of the piston (1) by casting.

The respective screw shaft insertion holes (4) and (4) of the respective pin ends (2a) and (2a) of the piston pin (2) are inserted into the respective leg screw portions (5a) and (5a) of the respective screw shafts (5) and (5). The pin ends (2a) and (2a) are received by the pin receiving seats (8) and (8), respectively. A pair of nuts (7) (7)
Is screwed into each of the leg screw portions (5a) (5a), whereby each pin end (2a) (2a) is pressed and fixed to the pin receiving seat (8). The “iron-based material” includes carbon steel and alloy steel. As the carbon steel, for example, a rolled material for general structure or carbon steel for machine structure is used, and as the alloy steel, for example, chromium steel, nickel chrome steel, chromium molybdenum steel, manganese steel, or stainless steel is preferably used.

[0012]

【The invention's effect】

(I). First, the nut (7) does not loosen. First, both the pin seat (8) and the nut (7) that hold the pin ends (2a) and (2a) of the piston pin (2) are made of an iron-based material. The thermal expansion coefficients are the same or almost the same. Therefore, when the temperature of the piston (1) rises due to the operation of the engine, the nut
(7) is pulled greatly toward the pin seat (8), and the nut
The tightening force of (7) does not increase.

Next, since the nut (7) is made of a tough iron-based material, its threads are not easily deformed by the compressive force of the tightening of the nut (7). And since the pin seat (8) is also made of a tough iron-based material, it is not easily deformed by the compressive force. As described above, the combination of the fact that the tightening force of the nut (7) does not increase and the fact that both the thread of the nut (7) and the pin seat (8) have high mechanical strength and are hard to be deformed by compression makes the nut ( 7) is less likely to loosen early and has excellent durability.

(B). The procedure for assembling the piston pin (2) to the piston (1) can be performed easily and efficiently.
With the skirt (12) of the piston (1) facing upward and the connecting rod (55) fitted in advance on the piston pin (2), the screw shaft insertion hole (4) of the piston pin (2) is inserted into the screw shaft (5). ), And the nut (7) is screwed into the leg screw (5a) of the screw shaft (5) and tightened. At this time, the leg screw (5a) is visible without being hidden by the piston pin (2), and the leg screw (5a) is located near the opening in the piston (1). The nut (7) is easily fitted into the part (5a), and the work of assembling the piston pin (2) to the piston (1) can be performed easily and efficiently.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. ○ Embodiment 1 See FIGS. 1 (A) and 1 (B) The pin ends (2a) and (2a) of the piston pin (2) are fixed to the aluminum alloy piston (1) via the screw type fixing means (3).
Screw shaft insertion holes at each pin end (2a) (2a) of piston pin (2)
(4) Penetrate (4). Each leg screw part (5a) (5a) of the pair of screw shafts (5) (5) of the screw type fixing means (3) is inserted into each screw shaft insertion hole.
(4) Pass through (4).

The screw type fixing means (3) includes an annular connecting body (6) made of carbon steel or stainless steel for machine structure, and a pair of screw shafts (5) made of carbon steel or stainless steel for machine structure.
(5) and a pair of nuts (7) (7) made of carbon steel or stainless steel for machine structure. A pair of screw shafts (5) and (5) are fixedly connected to the left and right side portions of the connecting body (6). An annular reinforcing frame made of carbon steel or stainless steel for machine structure (13) over a part of the length of the two screw shafts (5) (5).
Is fixed. Portions of the reinforcing frame (13) connected to the screw shafts (5) (5) are fixedly provided as pin seats (8) (8).

The connecting member (6) is a crown portion of the piston (1).
(9) The inside of the wall is fixed by casting. Each screw shaft insertion hole (4) at each pin end (2a) (2a) of the piston pin (2)
(4) is inserted from below into each leg screw portion (5a) (5a) of each screw shaft (5) (5), and each pin end (2a) (2a) is inserted into each pin seat (8). (8)
To be received. By screwing a pair of nuts (7) and (7) into the leg screw portions (5a) and (5a), the pin ends (2a) and (2a)
Is pressed and fixed to the pin seat (8).

Embodiment 2 FIG. 2 shows a second embodiment of the present invention, which is different from the first embodiment in that, as shown in FIG.
(8) is characterized in that they are formed in a circular flange shape independently of each other.

[Brief description of the drawings]

1 shows a first embodiment of the present invention, wherein FIG. 1 (A) is a longitudinal sectional front view showing a state where a piston pin is assembled to a piston, and FIG. 1 (B) is an exploded perspective view of a screw type fixing means.

FIG. 2 is a perspective view of a main part of a screw-type fixing means according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional front view showing a state in which a piston pin is attached to a piston according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piston, 2 ... Piston pin, 2a ... Pin end part, 3 ... Screw type fixing means, 4 ... Screw shaft insertion hole, 5
... screw shaft, 5a ... leg screw part, 6 ... connecting body, 7 ... nut, 8 ... pin seat, 9 ... crown part.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasumichi Kamata 64 Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Works, Ltd. References: Japanese Utility Model Hei 5-5079 (JP, U) Japanese Utility Model Showa 58-25641 (JP, U) Japanese Utility Model Showa 59-115835 (JP, U) Japanese Utility Model Showa 58-100239 (JP, U) Japanese Utility Model Showa 56-118934 (JP, U) Actually open 56-39833 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16J 1/18 F02F 3/00 301

Claims (1)

(57) [Claims] 1. An aluminum alloy piston (1) is fixed to each end (2a) (2a) of a piston pin (2) via a screw type fixing means (3). Screw shaft insertion holes at pin ends (2a) (2a)
(4) (4) is passed through, and each leg screw part (5a) (5a) of the pair of screw shafts (5) (5) of the screw type fixing means (3) is inserted into each screw shaft insertion hole.
(4) In a device for fixing a piston pin to an aluminum alloy piston of an internal combustion engine, the screw-type fixing means (3) includes a connecting body (6) and a pair of ferrous material. Screw shaft (5) (5) and a pair of nuts (7) made of ferrous material
(7), and a pair of screw shafts (5) and (5) are fixedly extended to both sides of the connecting body (6), respectively. The pin seats (8) and (8) made of an iron-based material are fixed, and the connecting body (6) is fixed to the inside of the wall of the crown (9) of the piston (1) with a cast-in. Insert each screw shaft insertion hole (4) (4) of each pin end (2a) (2a) of 2) into each leg screw portion (5a) (5a) of each screw shaft (5) (5). The pin ends (2a) and (2a) are received by the pin seats (8) and (8), respectively, and a pair of nuts (7) and (7) are connected to the leg screw portions (5).
a) an aluminum alloy for an internal combustion engine, wherein each of the pin ends (2a) and (2a) is pressed and fixed to a pin seat (8) (8) by being screwed into (5a). Device for fixing piston pins to pistons made of steel