JPH0550046U - Internal combustion engine pistons - Google Patents

Abstract

(57) [Abstract] [Purpose] An annular groove was formed in the second land to provide a pressure adjusting chamber, and the second land between the annular groove and the ring groove had a thin plate shape with low strength. Even in the case, the piston of the internal combustion engine capable of preventing the damage of the second land is provided. An annular groove is formed along a piston ring in a second land of the piston, a pressure adjusting chamber is formed in this portion, and the cylinder into which the piston is fitted and the second
A support member that abuts against and supports the upper wall and the lower wall of the annular groove is fitted into the annular groove so that the gap between the land and the pressure adjusting chamber communicate with each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 In order to reduce the consumption of engine oil by stabilizing the behavior of the piston ring, the present invention relates to a piston in which an annular groove is formed in the second land between the top ring and the second ring, the annular groove The present invention relates to a piston of an internal combustion engine capable of preventing breakage of a second land that has a shape that vertically protrudes in a thin plate shape.

[0002]

[Prior Art]

 An annular ring groove is formed on the side surface of the piston, and in this ring groove, a compression ring (top ring) for preventing high-pressure gas from leaking from the combustion chamber to the crank chamber, Oil rings for scraping off the excess engine oil retained in the gap between the cylinder and the piston are fitted in the gaps.

The top ring tilts so as to be twisted in the ring groove, and the engine oil leaks excessively from the crank chamber side to the combustion chamber side, or oil rises or high pressure in the combustion chamber occurs. Since the ability to seal the gas of the above will decrease and the amount of blow-by gas will increase, it is necessary to stabilize the posture of this top ring and ensure the retention of the sealing property. Therefore, as shown in FIG. 9, an annular groove 3 is formed along the piston ring 1 on the second land 2a between the top ring 1a and the second ring 1b, and the pressure is adjusted in the space surrounded by the annular groove 3. There is a chamber 4 formed.

By forming the pressure adjusting chamber 4, the volume of the gap 7 between the cylinder liner 6 fitted in the cylinder 5 and the second land 2a is increased, and the gap 7 and the pressure adjusting communicating with the gap 7 are increased. The pressure inside the chamber 4 is adjusted to be significantly lower than the pressure inside the combustion chamber 8. By causing a large pressure difference between the pressure in the combustion chamber 8 and the pressure in the pressure adjusting chamber 4 as described above, the top ring 1a is pressed against the lower wall 9a of the top ring groove 9 below the second land 2a. In other words, the behavior of the top ring 1a in the top ring groove 9 is stabilized and the gas sealing ability is enhanced.

Further, in the stroke of the reciprocating motion of the piston 10, especially in the compression stroke and the explosion stroke where the pressure in the combustion chamber 8 becomes high, the sealing property of the top ring 1a becomes very important. By forming the pressure adjusting chamber 4 in the second land 2a of the piston 10, the pressure rise of the gas flowing into the second land 2a is suppressed to a low level, and the pressure in the pressure adjusting chamber 4 is In the compression stroke and the explosion stroke, the pressure in the combustion chamber 8 becomes significantly lower than that in the combustion chamber 8, and the effect of stabilizing the behavior of the top ring 1a is exhibited.

[0006]

[Problems to be solved by the device]

 As described above, when the annular groove for forming the pressure adjusting chamber is formed in the second land, the second land between this annular groove and the ring grooves above and below this annular groove are as shown in FIG. It has a thin plate-like shape. Then, due to the top ring accompanying the reciprocating motion of the piston and the swinging of the second ring in the ring groove, a pressing force is applied to the thin plate-shaped second land, and a crack is generated as shown by a star in the figure, This second land is easily damaged. Further, if the second land is damaged, the fragments of the second land will be seized on the cylinder liner due to the reciprocating motion of the piston. This problem often occurs because the width of each piston land including the second land has to be narrowed, especially with the recent trend of increasing the number of piston rings in order to reduce oil consumption. It is supposed to do.

Therefore, as shown in FIG. 10, the diameter of the second land 2a between the top ring 1a and the second ring 1b is made smaller than the diameters of the other piston lands 2 to make the second land 2a smaller. Although it is possible to prevent the damage of the second land 2a by forming the concave portion 11 in the entire 2a, in this case, the behavior of the top ring 1a and the second ring 1b in the ring groove is stable. However, there is a problem that the piston ring tilts in the ring groove, the sealing property deteriorates, the amount of blow-by gas increases, or oil rises to increase oil consumption.

In view of the above problems, the present invention forms an annular groove to provide a pressure adjusting chamber in the second land, and the second land between the annular groove and the ring groove is a thin plate. An object of the present invention is to provide a piston for an internal combustion engine that can prevent the damage of the second land even when the piston has a low strength shape.

[0009]

[Means for Solving the Problems]

 The piston of the internal combustion engine of the present invention for achieving the above object has an annular groove formed along the piston ring in the second land of the piston, a pressure adjusting chamber is formed at this portion, and the piston is inserted into the annular groove. A support member that abuts against and supports the upper wall and the lower wall of the annular groove is inserted into the annular groove so that the gap between the cylinder and the second land and the pressure adjusting chamber communicate with each other. The configuration is characterized in that

[0010]

[Work]

 The piston of the internal combustion engine according to the present invention has the above-described structure, and the support member provided in the annular groove has the second land between the annular groove and the tompling groove into which the top ring fits, and the annular land. The second land between the groove and the second ring groove into which the second ring fits is abutted on and supported by the upper and lower walls of the annular groove so as to reinforce from the inside of the annular groove. Therefore, due to the swinging of the piston ring in the ring groove caused by the reciprocating motion of the piston, excessive stress is applied to the thin plate-shaped second land, and the second land is damaged. Can be prevented.

[0011]

【Example】

 Next, an example in which the embodiment of the present invention is applied to the piston 10 having the pressure adjusting chamber 4 shown in FIG. 9 will be described with reference to the drawings. First, in the first embodiment of the present invention, as shown in FIGS. 1 and 2, a support member 12 having a U-shaped cross section is fitted in the annular groove 3 formed in the second land 2a. The base portion 12a of the support member 12 is in contact with the bottom portion 3a of the annular groove 3, and the holding portions 12b and 12c of the support member 12 are in contact with the upper wall 3b and the lower wall 3c of the annular groove, respectively. ing. A top ring groove 9 and a second ring groove 13 are formed above and below the second land 2a in which the annular groove 3 is formed.

The top ring that fits into the top ring groove 9 and the second ring that fits into the second ring groove 13 oscillate in each ring groove by the reciprocating motion of the piston. As a result, the second land 2a, which has the shape of a thin plate, is stressed so as to be pressed from the ring groove toward the annular groove 3. Therefore, this stress is applied from the inside of the annular groove 3 to the annular groove 3. By being supported by the support member 12, it is possible to prevent an excessive stress from being applied to the second land 2a having the reduced strength.

In the second embodiment shown in FIGS. 3 and 4, a ventilation hole 14 is opened in the base portion 12a of the support member 12 having a U-shaped cross section in the first embodiment, and contrary to the case of FIG. The base portion 12a is fitted in the annular groove 3 with the base portion 12a facing the opening side of the annular groove 3. The support member 12 of this embodiment also receives the stress due to the swing of the top ring and the second ring instead of the second land 2a.

The support member 12 having a U-shaped cross-section with the vent hole 14 according to this embodiment forms the annular groove 3 so that the pressure adjusting chamber 4 formed in this portion is provided with the second land 2a and the cylinder. It is for opening to the clearance between. By forming the ventilation hole 14, the second land 2a can be reinforced without impairing the effect of keeping the pressure in the pressure adjustment chamber 4 formed in the second land 2a lower than the pressure in the combustion chamber. can do.

Next, in the third embodiment shown in FIGS. 5 and 6, in the circumferential direction of the annular groove 3, a holding portion 12b that abuts on the second land 2a near the top ring 1a and a second portion near the second ring 1b. The holding portions 12c contacting the two lands 2a are alternately formed, and the holding portion 12b contacting the upper wall 3b of the annular groove 3 and the holding portion 12c contacting the lower wall 3c are connected by the base portion 12a. It is a thing.

Also in the case of this embodiment, similarly to each of the above-described embodiments, the holding portions 12b and the holding portions 12c, which are alternately arranged in the circumferential direction along the piston ring 1, are formed from the inner side of the annular groove 3. The upper wall 3b and the lower wall 3c of the annular groove 3 are supported, and the second land 2a protruding in a thin plate shape is pressed by the swing of the piston ring 1 and is reinforced so as not to be broken. Embodiment 4 shown in FIG. 7 and FIG. 8 has a holding portion 12b that abuts on the upper wall 3b of the annular groove 3 over the entire circumference of the annular groove 3, and similarly over the entire circumference of the annular groove 3. A holding portion 12c that abuts the lower wall 3c is provided, and the holding portion 12b and the holding portion 12c are connected by a base portion 12a similar to that in the third embodiment. Also in the case of this embodiment, the action and effect are the same as those of the above-mentioned embodiments. Incidentally, in the case of this embodiment, a structure having a high strength against the stress applied from above and below such as a honeycomb structure can be formed, and therefore, this is a preferable shape as a reinforcing member for the second land 2a.

Although four examples have been given above as examples, the shape of the support member 12 is not limited to these examples, and supports the upper wall 3b and the lower wall 3c of the annular groove 3. Any shape may be used as long as it can receive the pressing force applied to the second land 2a. The material of the supporting member 12 is preferably made of a material having a coefficient of thermal expansion substantially equal to that of the material of the piston 10 in consideration of the coefficient of thermal expansion. For example, when the piston 10 is made of aluminum. The support member 12 is also preferably made of aluminum, an aluminum alloy, or the like.

[0018]

[Effect of the device]

 In the piston of the internal combustion engine of the present invention, an annular groove is formed in the second land of the piston along the piston ring, a pressure adjusting chamber is formed in this portion, and the cylinder into which the piston is fitted and the second land. A support member that abuts against and supports the upper wall and the lower wall of the annular groove is fitted into the annular groove so that the gap between the pressure adjusting chamber and the gap between The following effects can be achieved.

A support member provided in the annular groove includes a second land between the annular groove and a tompling groove into which the top ring fits, and a second ring in which the annular groove and the second ring fit. Since the second land portion between the groove and the groove is abutted against and supports the upper wall and the lower wall of the annular groove so as to reinforce from the inside of the annular groove, the ring groove accompanying the reciprocating motion of the piston It is possible to prevent a situation in which the thin plate-shaped second land is subjected to excessive stress due to the swinging of the piston ring inside the second ring and the second land is damaged.

Further, since the second land, which has a thin plate-like shape and has a reduced strength, can be reinforced by this support member, particularly in the compression stroke and the explosion stroke of the piston, the annular groove is formed. Since the pressure in the pressure regulation chamber formed by the pressure can be made significantly smaller than the pressure in the combustion chamber, the behavior in the ring groove of the piston ring can be stabilized and the oil rise and blow-by gas amount can be reduced. Can be planned.

[Brief description of drawings]

FIG. 1 is a sectional view of a supporting member used for a piston of an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a partial perspective view of the support member of FIG.

FIG. 3 is a sectional view of a supporting member used for a piston of an internal combustion engine according to a second embodiment of the present invention.

4 is a partial perspective view of the support member of FIG.

FIG. 5 is a sectional view of a supporting member used for a piston of an internal combustion engine according to a third embodiment of the present invention.

6 is a partial perspective view of the support member of FIG.

FIG. 7 is a sectional view of a supporting member used for a piston of an internal combustion engine according to a fourth embodiment of the present invention.

8 is a partial perspective view of the support member of FIG.

FIG. 9 is a sectional view of a main part of a piston of a conventional internal combustion engine used in the present invention.

FIG. 10 is a sectional view of a main part of a piston of a conventional internal combustion engine.

[Explanation of symbols]

1 Piston ring 2a 2nd land 3 Annular groove
3b Upper wall 3c Lower wall 4 Pressure adjustment chamber 5 Cylinder 7 Gap 10
Piston 12 support member.

Claims (1)

[Scope of utility model registration request] 1. A second land of the piston is formed with an annular groove along the piston ring, a pressure adjusting chamber is formed at this portion, and a gap between the cylinder into which the piston is fitted and the second land. A piston for an internal combustion engine, wherein a support member that abuts and supports the upper wall and the lower wall of the annular groove is fitted into the annular groove so that the pressure adjusting chamber and the pressure adjusting chamber communicate with each other.