JPH07233757A - Piston - Google Patents

Abstract

PURPOSE:To prevent the slap noise by fitting an outer ring member, which is energized against a cylinder, to a piston main body without changing a conventional piston assembling process. CONSTITUTION:A piston is formed of a piston main body 1, plural outer ring support members 2 and an outer ring member 3. The outer ring support members 2 are supported in both sides of a piston skirt 6 by pins 5 directed in a piston pin 8 freely to be turned, and an engaging part 3a of the outer ring member 3 having a cylindrical surface is loosely fitted in a groove 2a formed in the outer ring support member 2, and the outer ring member 3 is energized outward by elastic members 4 fitted to the piston skirt 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston of an internal combustion engine, and more particularly to a piston which effectively suppresses slap noise generated from the piston.

[0002]

2. Description of the Related Art A slight gap is provided between a piston and a cylinder of an internal combustion engine in order to facilitate the operation of the piston. Therefore, when the piston reciprocates, it swings around a piston pin. It is known that a piston collides with the cylinder wall to generate a slap sound.

This slap sound is one of the causes of noise generated from an internal combustion engine, and various measures for preventing it have been conventionally proposed. For example, Japanese Utility Model Laid-Open No. 56-85045 discloses a piston in which an outer ring member is attached to the outside of a piston skirt via a cylindrical rubber cushioning material, and a stopper is attached so that the outer ring member does not fall off. ing. In this piston, the rubber cushioning member cushions the impact generated when the cylindrical outer ring member collides with the cylinder wall, and reduces the slap sound.

[0004]

By the way, the means of the above-mentioned publication in which a cylindrical outer ring member is fitted on the outer periphery of the piston skirt via a cushioning material is disclosed in the above-mentioned external means each time the piston changes its posture in the cylinder hole. Since the ring member collides with the cylinder wall, it is not possible to stop the generation of the slap sound, and there is a drawback that the noise is only slightly reduced.

The present invention has been made in view of the above problems. An outer ring member attached to a piston skirt is formed so that its posture and relative position can be changed, and this outer ring member is pressed against a cylinder side. An object of the present invention is to provide a piston which prevents the generation of slap noise and requires almost no modification of the conventional piston assembly process for assembling the outer ring member.

Another object of the present invention is to provide a mounting structure for an outer ring supporting member suitable for stably supporting the outer ring member. Still another object of the present invention is to provide a structure of the outer ring member in which the outer ring member slides stably on the inner wall of the cylinder and effectively cushions between the outer ring member and the piston skirt.

[0007]

A piston of the present invention for achieving the above object is a piston for an internal combustion engine, wherein pins are provided on both sides of the piston pin and below the piston ring groove. The outer ring support members are rotatably attached to the respective pins, and the outer ring support members are provided with engaging grooves in the respective outer lateral directions. Loosely fit the ring member,
An outer ring member is interposed between the piston skirt and the cylinder wall, and an elastic member interposed between the outer ring member and the piston skirt prevents contact between the outer ring member and the piston skirt, and at the same time the outer ring member is It was urged toward the outside.

As described above, since the outer ring member, the outer ring support member and the elastic member are arranged between the piston skirt and the inner wall of the cylinder, the piston skirt is made thinner than the conventional one in order to make room for these members. To do. The shape of the outer ring supporting member is not particularly limited, but it can be formed in a laterally long shape so as to stably support the outer ring member, and can be adapted to the cylinder hole as an arc shape. Further, it is preferable that the engagement groove be wide in the longitudinal direction in order to stably support the outer ring member. Further, the engagement groove may be arcuate to facilitate conforming to the inner surface of the cylinder, or may be linear. Further, the engaging groove may be provided only in a necessary portion without continuously forming the whole.

Further, the structure of the portion that axially supports the outer ring support member on the piston body is such that a groove deepening the portion for mounting the pin is formed below the piston ring groove of the piston body. A holding portion for forming a pin hole through which the pin is inserted can be provided so as to project downward from the main body and can be pivotally supported. The outer ring member is preferably formed of a plate and widely covers the side of the piston skirt in order to disperse the force that presses the cylinder wall due to a change in the posture of the piston, but the present invention is not limited to this, and the present invention is not limited to this. It can have a deformed shape. The point is that the outer ring member is in contact with the cylinder wall and is driven by the piston body, so that the posture change of the piston skirt can be buffered by the elastic member.

Therefore, it is preferable to form the outer shape of the outer ring member into a cylindrical surface shape that fits the inner wall of the cylinder.
The engagement portion for loosely fitting the outer ring member in the engagement groove can be formed by bending the outer ring member inwardly into an inner flange shape. However, the present invention is not limited to this, and can be formed in any shape, for example, by forming a protrusion-shaped engaging portion in a necessary portion. The elastic member is usually rubber or resin, but is not particularly limited. Other elastic bodies such as springs can also be used.

[0011]

In the outer ring member attached to the piston skirt as described above, the posture is changed with respect to the outer ring support member by loosely fitting the engaging portion provided on the outer ring member into the engaging groove. It is possible to move in the engagement groove direction. Therefore, the outer ring member can change the posture with respect to the piston skirt in the lateral direction of the piston pin and can move laterally from the piston body, and can be displaced in the arrangement direction of the piston pin with respect to the piston body.

The outer ring member operates as described above, and is urged outward by the elastic member, constantly pressed against the cylinder wall, and reciprocates in the cylinder while sliding on the cylinder wall surface. To do. The elastic member interposed between the outer ring member in contact with the cylinder wall and the piston skirt cushions the collision between the piston head and the cylinder wall, and the outer ring member and the piston skirt, and prevents the generation of slap noise. To prevent.

The above-mentioned means for attaching the outer ring supporting member and the outer ring member to the pin attached to the piston body can be assembled separately from the original piston assembling step of assembling the piston ring, connecting rod, etc. to the piston body. As such, the present invention can be practiced with little modification to the conventional piston assembly process. Further, a groove for deepening the portion for mounting the pin on the lower side of the piston ring groove is formed in the portion for mounting the outer ring supporting member, and a holding portion for making the pin hole is projected downward from the main body of the outer ring supporting member. The means for arranging allows the outer ring member to be retracted from the piston skirt by reducing the portion of the piston skirt that is shaved as much as possible and by slightly rotating the outer ring support member.

Further, the outer ring member is formed into a cylindrical plate member covering the lower piston skirt of the outer ring support member, and the upper end portion is bent inward in the shape of an inner flange and loosely fitted in the engagement groove. The means has a simple structure and can smoothly perform the operation of buffering the posture change of the piston body.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings with reference to the accompanying drawings. As shown in FIGS. 1 to 3, the piston of this embodiment is constructed by assembling a piston body 1, an outer ring support member 2, an outer ring member 3 and an elastic member 4. Reference numeral 5 shown in FIG. 1 is a pin that pivotally supports the outer ring support member 2 on the piston body 1.

The piston body 1 has a piston ring groove 1 into which a piston ring 1b is fitted on the peripheral surface on the crown portion 1a side.
c, and a boss portion (not shown) in the piston skirt 6
A piston pin 8 for pivotally supporting the connecting rod 7 is attached to the base of the piston rod. The basic shape is the same as that of a conventional mass-produced piston, and the piston skirt 6 for attaching the outer ring support member 2 and the outer ring member 3 is formed thin. ing. Further, since the outer ring member 3 is arranged on both sides of the piston ring 1b (FIG. 2), the outer ring support member 2, the outer ring member 3, the elastic member 4 and the pin 5 each have two sets (only one set is shown in FIG. 1). I prepared it.

The elastic member 4 of this embodiment (4 in this embodiment)
Individual pieces) were elastically engaged with the holding holes 4a formed in the piston skirts 6 on both sides of the piston pin 8 and attached. The outer ring support member 2 has a main body portion formed in an arc shape,
A groove 2a in the circumferential direction of the piston skirt 6 was formed, a holding portion 2b (two pieces) was provided on the lower side of the main body, and a pin hole 2c for inserting the pin 5 was opened in this. The outer ring support member 2
And, as a measure of the circumferential length of the outer ring member 3, about 1/3 of the circumference of the piston skirt 6 (thus, about 2 / about 2 /
3 laps). However, the present invention is not limited to this numerical value, and may be appropriately selected according to the actual situation.

A holding portion 6a for axially supporting the outer ring supporting member 2
Is in the groove 6b formed in the upper part of the piston skirt 6,
The outer ring member 3 was attached so as to fit in the cylinder hole 9a, and a pin hole 6c for inserting the pin 5 was opened in this. Therefore, the outer ring support member 2 pivotally supported by the holding portion 6 a can be pivoted around the pin 5 to be projected and retracted outward from the piston skirt 6.

The outer ring member 3 is, for example, a plate having a size of about 1 mm and is formed into a cylindrical surface that fits the inner surface of the cylinder liner 9. The upper edge of the outer ring member 3 is bent into an inner flange shape, and is inserted into the groove 2a. 3a was formed. To engage the outer ring member 3 with the outer ring support member 2, the engaging portion 3a may be inserted into the groove 2a. The width of the groove 2a is made slightly larger than the thickness of the engaging portion 3a so that the outer ring member 3 can move in the thrust direction of the piston pin 8 in the groove 2a and is bent to some extent with respect to the outer ring support member 2. Formed possible. Therefore, the posture of the piston body 1 changes in the cylinder hole 9a,
Even when eccentric, the outer ring member 3 can always slide while being in contact with the inner wall surface of the cylinder liner 9. The groove 2a
Can be formed parallel to the direction of the piston pin 8 instead of being arcuate.

Next, a procedure for assembling the piston body 1, the outer ring support member 2, the outer ring member 3 and the elastic member 4 will be described. First, the piston body 1 and the connecting rod 7 are assembled by the piston pin 8, and a snap ring (not shown) is used as in the conventional case.
Etc. Next, the elastic member 4 is fixed in the holding hole 4a with an adhesive or the like. Next, the holding portion 2b of the outer ring supporting member 2 was attached to the holding portion 6a of the piston skirt 6, the pin 5 was inserted into the pin holes 2c and 6c, and the outer ring supporting member 2 was rotatably attached.

Then, the engaging portion 3a of the outer ring member 3 is inserted into the groove 2a of the outer ring supporting member 2, and is inserted into the cylinder hole 9a in this state. In the cylinder hole 9a, the outer ring member 3
Can slide in the cylinder hole 9a integrally with the piston body 1 without coming off from the outer ring support member 2. As can be understood from the above description, since the outer ring member 3 is attached after the piston body 1 and the connecting rod 7 are assembled, there is almost no need to change the conventional assembly process, which is extremely advantageous in terms of cost. .

The operation of the piston of this embodiment assembled as described above will be described with reference to FIGS. First, the operation when the piston body 1 makes a swinging motion around the piston pin 8 will be described. In FIG. 2, the piston body 1
However, when the piston pin 8 is rotated to the left as viewed in the figure, the piston skirt 6 is inclined so that the right side of the figure approaches the inner wall of the cylinder liner 9 and the left side thereof moves away.

As described above, since the two outer ring members 3 are biased outward by the elastic members 4, the two outer ring members 3 are rotated / bent at the pin 5 and the engaging portion 3a to have their postures. It is changed and pressed against the wall surface of the cylinder liner 9 as shown in FIG. Therefore, the piston body 1
2 rotates to the opposite side of FIG. 2, the outer ring member 3 is also pressed against the wall surface of the cylinder liner 9. Moreover, when the posture of the piston body 1 is changed, abrupt movement of the piston body 1 is buffered by the elastic member 4, and the outer ring member 3 and the piston skirt 6 are prevented from colliding. Therefore, the slap sound generated when the piston body 1 changes its posture is almost prevented.

As described above, the outer ring member 3 can move in the thrust direction of the piston pin 8. Therefore, as shown in FIG. 3, the piston body 1 is inserted into the cylinder hole 9a.
Even when it is displaced in the direction shown by the arrow in the drawing, the outer ring member 3
Can reasonably maintain the state of being inscribed in the cylinder liner hole 9.

[0025]

As described above, in the piston of claim 1 of the present invention, the outer ring member is arranged between the piston skirts on both sides of the piston pin and the cylinder inner wall, and the outer ring member is directed toward the cylinder inner wall. Since an elastic member for urging is attached, and the outer ring member can be slid in contact with the inner wall of the cylinder irrespective of the posture and displacement of the piston body in the cylinder, it is possible to change the posture of the piston by the cushioning action of the elastic member. The noise due to the slap sound generated when the piston collides with the cylinder wall can be reduced. Moreover, since it is not necessary to change the conventional piston assembly process for carrying out the present invention, the cost is extremely advantageous.

Further, in the piston of claim 2, a groove for deepening the portion for mounting the pin for mounting the outer ring supporting member is formed,
Since the holding portion of the pin is provided so as to project downward from the outer ring support member main body, it is possible to reduce the thickness of the piston skirt as much as possible, and the outer ring support member is slightly rotated. By moving, the effect of making the outer ring member project and retract from the piston skirt is obtained.

Further, in the piston of the third aspect, the outer ring member is formed of a cylindrical plate body covering the piston skirt, and the inner flange-shaped engaging portion is formed in the upper portion, so that the piston has a simple structure. It is possible to smoothly perform the operation of buffering the posture change of the main body.

[Brief description of drawings]

FIG. 1 is an exploded view of a piston according to an embodiment of the present invention with a part of the piston omitted.

FIG. 2 is a longitudinal sectional view of an essential part showing a state in which the piston is attached to the engine shown in FIG.

3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

 1 piston body 2 outer ring support member 2a groove 2b holding part 2c pin hole 3 outer ring member 3a engaging part 4 elastic member 4a holding hole 5 pin 6 piston skirt 8 piston pin

Claims (3)

[Claims] 1. An outer ring support member is rotatably supported by pins attached to both sides of a piston pin provided on a piston of an internal combustion engine and below a piston ring groove, respectively, in a direction in which the piston pin is arranged. Then, the outer ring members are loosely fitted in the respective engagement grooves provided in the outer lateral direction of the outer ring support member so that the outer ring members can be retracted from the piston body and the posture and relative position can be changed. An outer ring member is interposed between the skirt and the cylinder wall, and an elastic member interposed between the outer ring member and the piston skirt prevents contact between the outer ring member and the piston skirt, and at the same time the outer ring member is Piston urged outward. 2. A holding portion for forming a groove deepening a portion for mounting the pin below the piston ring groove of the piston main body, and forming a pin hole for inserting the pin downward from the outer ring support member main body. The piston according to claim 1, wherein the piston is provided. 3. The outer ring member is formed into a cylindrical surface that covers the side of the lower piston skirt of the outer ring support member by processing a plate body, and the upper end portion is bent inward to form an inner flange shape. The piston according to claim 1 or 2, wherein an engaging portion that is loosely fitted in the engaging groove is formed.