JPH08200499A - Combination oil ring - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the followability of the combined oil ring to the cylinder inner wall in an internal combustion engine. In a combined oil ring including an oil ring body 1 obtained by dividing upper and lower rails 3 and 4, and a coil spring 2 for urging the oil ring body 1 in a radial direction, the upper and lower rails 3 and 4 are arranged in a vertical direction. The protrusion 7 and the locking groove 8 for restricting the movement away from each other are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved combination oil ring mounted on a piston of an internal combustion engine.

[0002]

2. Description of the Related Art A piston of an internal combustion engine is provided with a pressure ring mainly having a gas sealing function and an oil ring for adjusting a lubricating oil film attached to the inner wall of the cylinder.

As the oil ring, there is a combined oil ring provided with a coil spring for urging the oil ring body slidingly in contact with the inner wall of the cylinder in the radial direction.

As a conventional combined oil ring, for example, as shown in FIG. 5, an oil ring main body 1 is integrally formed with upper and lower rails 3 and 4 and a column portion 5 connecting the upper and lower rails 3 and 4 to form an I-shape. Some of them have a cross-sectional shape.

A coil spring 2 is fitted behind the oil ring body 1. The oil ring body 1 is mounted in the oil ring groove of the piston, and is pressed against the inner wall of the cylinder by the urging force of the coil spring 2 to scrape off the lubricating oil attached to the inner wall of the cylinder as the piston reciprocates. . (Kaikaihei 5-8128,
See Japanese Utility Model Laid-Open No. 54-53108).

[0006]

By the way, the bore radius of the inner wall of the cylinder becomes non-uniform due to the influence of heat, etc., and there is a possibility that uneven portions in which the inner wall of the cylinder partially inclines with respect to the cylinder axial direction occur. is there.

However, in such a conventional combined oil ring body 1, since the upper and lower rails 3 and 4 are integrally formed, the rigidity in the bending direction is high and the oil is generated on the inner wall of the cylinder. One of the upper and lower rails 3 and 4 may hit the inner wall of the cylinder with respect to the uneven portion, and the other may separate from the inner wall of the cylinder, making it difficult to ensure sufficient followability to deformation of the inner wall of the cylinder. There is a point.

Also, as a conventional combination oil ring,
For example, as shown in FIG. 6, the oil ring body 1 may be formed by dividing the upper and lower rails 3 and 4.

Also in this case, the coil spring 2 is fitted behind the oil ring body 1. Oil ring body 1
Is mounted in the oil ring groove of the piston, and the upper and lower rails 3 and 4 are independently pressed against the inner wall of the cylinder by the urging force of the coil spring 2 to provide sufficient followability when the uneven portion of the inner wall of the cylinder occurs. It is designed to be secured (see Japanese Utility Model Laid-Open No. 64-49762).

However, in such a conventional combined oil ring body 1, the upper and lower rails 3 and 4 are pressed against the upper surface 32 and the lower surface 33 of the oil ring groove 31 of the piston 30 by the urging force of the coil spring 2. Therefore, there is a problem in that the friction between the upper and lower rails and the oil ring groove increases, and the followability to the uneven portion of the cylinder inner wall deteriorates.

An object of the present invention is to solve the above problems and improve the followability of the combined oil ring to the inner wall of the cylinder.

[0012]

The invention according to claim 1 is provided with an oil ring main body in which upper and lower rails are divided,
A combined oil ring including a coil spring for urging the oil ring main body in a radial direction includes restraint means for restraining movement of upper and lower rails in the vertical direction.

The combination oil ring according to claim 2 is
In the invention according to claim 1, a plurality of protrusions protruding from the lower surface of the upper rail are formed as restraint means for restricting the movement of the upper and lower rails in the vertical direction, and the protrusions are recessed in the upper surface of the lower rail. Forming a plurality of locking grooves for engaging the protrusions.

The combination oil ring according to claim 3 is
In the invention of claim 1, as a restraint means for restricting the movement of the upper and lower rails in the vertical direction, a single projection protruding from the lower surface of the upper rail is formed along the circumferential direction of the oil ring body, and the lower side A locking groove that is recessed in a concave shape on the upper surface of the rail and that engages the protrusion is formed along the circumferential direction of the oil ring body.

The combination oil ring according to claim 4 is
In the invention according to claim 3, the protrusion and the engaging groove are each formed in a T-shape in cross section.

The combination oil ring according to claim 5 is
In the invention according to claim 3, the protrusion is formed to have an L-shaped cross section.

A combination oil ring according to claim 6 is
In the invention according to any one of claims 1 to 5,
A surface layer made of a low wear material having a small friction coefficient is formed on at least one of the contact surfaces that are in sliding contact with each other between the protrusion and the locking groove.

[0018]

In the combined oil ring according to claim 1, the oil ring body is mounted in the oil ring groove of the piston, and is pressed against the inner wall of the cylinder by the urging force of the coil spring. Scrapes off the lubricating oil that has adhered to the inner wall of the cylinder.

Since the upper and lower rails of the oil ring body are formed separately, the upper and lower rails receive the biasing force of the coil spring and are displaced independently of each other in the radial direction of the piston. As a result, the upper and lower rails follow the minute irregularities formed on the cylinder inner wall to prevent a gap from being formed between the rail and the cylinder inner wall, and prevent the lubricating oil from being left on the cylinder inner wall.

Since the upper and lower rails are restricted from being separated from each other in the vertical direction by the restraining means, it is possible to prevent the upper and lower rails from being pressed against the upper surface or the lower surface of the oil ring groove by the urging force of the coil spring. As a result, the friction between the upper and lower rails and the oil ring groove can be reduced, the followability of the upper rail to the irregularities of the cylinder inner wall can be enhanced, and the amount of unlubricated oil left on the cylinder inner wall can be reduced.

In the combined oil ring according to the second aspect of the invention, the plurality of projections projecting from the lower surface of the upper rail engage with the plurality of locking grooves recessed in the upper surface of the lower rail, respectively, so that The rail is restricted from moving vertically. Therefore, it is avoided that the coil spring is pressed against the upper surface or the lower surface of the oil ring groove by the biasing force of the oil spring, the followability of the upper rail to the uneven portion of the cylinder inner wall is improved, and the amount of unlubricated oil left on the cylinder inner wall is reduced. be able to.

In the combined oil ring according to the third aspect of the present invention, a single projection projecting from the lower surface of the upper rail engages with a single locking groove recessed in the upper surface of the lower rail, so The rail is restricted from moving vertically. Therefore, the biasing force of the coil spring prevents the oil ring groove from being pressed against the upper surface or the lower surface of the oil ring groove, which improves the followability of the upper rail to the uneven portion of the cylinder inner wall, and reduces the amount of unlubricated oil left on the cylinder inner wall. be able to.

In the combined oil ring as set forth in claim 4, when the oil ring body is assembled, the abutment end of the upper rail is engaged with the abutment end of the lower rail to displace the upper and lower rails in the circumferential direction. Then, the T-shaped protrusion is inserted into the slit.

As a result, the upper and lower rails can be formed by using the linear material having the same cross-sectional shape in the circumferential direction, and the productivity can be improved.

In the combined oil ring according to the present invention, the L-shaped projection is radially arranged with respect to the locking groove of the lower rail in a state where the upper rail has a larger opening than the lower rail. To engage. As a result, the number of assembly steps can be reduced.

As a result, the upper and lower rails can be formed by using a linear material having the same cross sectional shape in the circumferential direction, and the productivity can be improved.

In the combined oil ring according to the sixth aspect, since the projection and the engaging groove are in sliding contact with each other through the surface layer having a small friction coefficient formed on the contact surface, friction between the upper and lower rails is reduced, It is possible to improve the followability of the upper and lower rails to the irregularities on the cylinder inner wall, and further reduce the amount of unlubricated oil left on the cylinder inner wall.

[0028]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the oil ring body 1
Is mounted in the oil ring groove 31 of the piston 30 and is pressed against the inner wall of the cylinder via the biasing force of the coil spring 2.

The oil ring body 1 includes the upper and lower rails 3,
It is formed by being divided into four. The upper and lower rails 3 and 4 have outer peripheral projections 6 and 10 that are in sliding contact with the inner wall of the cylinder.

A plurality of projections 7 projecting from the lower surface of the upper rail 3 are formed at predetermined intervals as restraint means for restricting the movement of the upper and lower rails 3 and 4 in the vertical direction (cylinder axial direction). A plurality of locking grooves 8 are formed on the upper surface of the lower rail 4 so as to be recessed in a concave shape to engage the protrusions 7.

The projection 7 is integrally formed with a neck portion 11 protruding from the lower surface of the upper rail 3 and a head portion 12 connected to the tip of the neck portion 11. The head 12 is formed in a rectangular parallelepiped larger than the neck 11.

The engaging groove 8 has a slit 13 for inserting the neck 11 of the protrusion 7, a recess 14 for inserting the head 12 of the protrusion 7, and an upper surface of the lower rail 4 connected to the slit 13 and the recess 14. And an assembly hole 16 that opens.

The recess 14 has a contact surface 15 for joining the head 12 of the projection 7 formed in a plane shape orthogonal to the cylinder axis.

In the projection 7, the contact surface 18 for joining the contact surface 15 of the recess 14 is formed in a plane shape orthogonal to the cylinder axis.

The projection 7 and the engaging groove 8 engage with each other with a predetermined gap in the piston radial direction, and the upper and lower rails 3 and 4 can be independently displaced in the piston radial direction within the range of this gap.

The opening width of the oil ring groove 31 in the cylinder axis direction is formed to be larger than the thickness of the oil ring main body 1 in the cylinder axis direction, and a predetermined gap is formed between them.

With the above construction, the operation will be described below.

When the oil ring body 1 is assembled, the protrusion 7 of the upper rail 3 is inserted into the assembling hole 16 of the lower rail 4 and the upper and lower rails 3, 4 are displaced in the circumferential direction to slit the protrusion 7. Insert through 13.

The oil ring body 1 is composed of upper and lower rails 3, 4
With the oil ring groove 3 of the piston 30 assembled
1 is pressed against the inner wall of the cylinder by the urging force of the coil spring 2, and along with the reciprocating movement of the piston 30, the outer peripheral projections 6 and 10 of the upper and lower rails 3 and 4 scrape off the lubricating oil attached to the inner wall of the cylinder. Drop it.

By the way, the bore radius of the inner wall of the cylinder becomes non-uniform due to the influence of heat or the like, and there is a possibility that an uneven portion in which the inner wall of the cylinder is partially inclined with respect to the cylinder axial direction is generated.

To cope with this, the upper and lower rails 3 and 4 of the oil ring body 1 are formed separately, so that the upper and lower rails 3 and 4 receive the biasing force of the coil spring 2 and are independent of each other. Displaces in the piston radial direction. As a result, the upper and lower rails 3 and 4 are 20μ generated on the inner wall of the cylinder.
It is possible to prevent a gap from being formed between the cylinder inner wall and the cylinder inner wall by following the uneven portion of about m, and it is possible to prevent the lubricating oil from being left on the cylinder inner wall.

When the piston 30 moves up, the lower rail 4 of the oil ring body 1 is seated on the lower surface 33 of the oil ring groove 31, as shown in FIG. At this time, since the upper and lower rails 3 and 4 are restricted from separating in the vertical direction by the engagement of the projection 7 and the locking groove 8, there is a gap between the upper rail 3 and the upper surface 32 of the oil ring groove 31. . Therefore,
Since the upper rail 3 is not pressed against the upper surface 32 of the oil ring groove 31 by the urging force of the coil spring 2, the friction between the upper rail 3 and the oil ring groove 31 is reduced, and the upper rail 3 with respect to the concavo-convex portion on the inner wall of the cylinder. It is possible to improve the follow-up property and reduce the amount of unlubricated oil left on the inner wall of the cylinder.

When the piston 30 descends, the upper rail 3 of the oil ring body 1 is seated on the upper surface 32 of the oil ring groove 31. At this time, since the upper and lower rails 3 and 4 are restricted from separating in the vertical direction by the engagement of the projection 7 and the locking groove 8, a gap is formed between the lower rail 4 and the lower surface 33 of the oil ring groove 31. Vacant Therefore, the lower rail 4 is not pressed against the lower surface 33 of the oil ring groove 31 by the urging force of the coil spring 2, the friction between the lower rail 4 and the oil ring groove 31 is reduced, and the cylinder of the lower rail 4 is reduced. It is possible to improve the followability to the uneven portion of the inner wall and reduce the amount of unlubricated oil left on the inner wall of the cylinder.

Further, the contact surface 15 of the recess 14 and the contact surface 18 of the projection 7 which are in sliding contact with each other may be provided with a surface layer made of a low wear material having a small friction coefficient.

In this case, the friction between the upper and lower rails 3 and 4 is reduced, the followability of the upper and lower rails 3 and 4 to the irregularities of the cylinder inner wall is increased, and the amount of unlubricated oil left on the cylinder inner wall is further reduced. be able to.

Next, another embodiment shown in FIG. 3 will be described. It should be noted that the same reference numerals are used for the portions corresponding to those in FIGS. 1 and 2.

As a restraint means for restricting the movement of the upper and lower rails 3, 4 away from each other in the vertical direction (cylinder axis direction), a single protrusion 47 projecting from the lower surface of the upper rail 3 extends along the circumferential direction of the oil ring body 1. On the other hand, a locking groove 48 is formed in the upper surface of the lower rail 4 so as to be recessed in a concave shape to engage the protrusion 47 along the circumferential direction.

The protrusion 47 is integrally formed with a neck portion 41 projecting from the lower surface of the upper rail 3 and a head portion 42 connected to the tip of the neck portion 41. The head 42 and the neck 41 are formed with a T-shaped cross section.

The engaging groove 48 has a slit 43 into which the neck portion 41 of the protrusion 47 is inserted and a recess 44 into which the head portion 42 of the protrusion 47 is inserted, and is formed with a T-shaped cross section.

The concave portion 44 has a contact surface 45 for joining the head 42 of the projection 47 formed in a plane shape orthogonal to the cylinder axis.

The protrusion 47 has a contact surface 49 for joining the contact surface 45 of the recess 44 formed in a plane shape orthogonal to the cylinder axis.

The projection 47 and the engaging groove 48 engage with each other with a predetermined gap in the piston radial direction, and the upper and lower rails 3 and 4 can be independently displaced in the piston radial direction within the range of this gap.

With the above construction, the operation will be described below.

At the time of assembling the oil ring body 1, the abutment end of the upper rail 3 is engaged with the abutment end of the lower rail 4,
The upper and lower rails 3 and 4 are displaced in the circumferential direction so that the T-shaped protrusion 47 is inserted into the slit 43.

Since the upper and lower rails 3 and 4 have the same cross-sectional shape in the circumferential direction, it is possible to form them using a linear material having the same cross-sectional shape, which improves the productivity.

When the upper and lower rails 3 and 4 are not formed into a perfect circle, the gap between the protrusion 47 and the locking groove 48 in the piston radial direction should be increased, or the upper and lower rails 3 and 4 should be formed.
It is necessary to fit the cylinder 4 into the inner wall of the cylinder while bringing it close to a perfect circle.

It is also conceivable to assemble the upper and lower rails 3 and 4 in a state where the upper and lower rails 3 and 4 are linearly formed and then bend the upper and lower rails 3 and 4 together.

Further, the contact surface 45 of the recess 44 and the contact surface 49 of the projection 47, which are in sliding contact with each other, may be provided with a surface layer made of a low wear material having a small friction coefficient.

In this case, the friction between the upper and lower rails 3 and 4 is reduced, the followability of the upper and lower rails 3 and 4 to the irregularities of the cylinder inner wall is increased, and the amount of unlubricated oil left on the cylinder inner wall is further reduced. be able to.

Next, another embodiment shown in FIG. 4 will be described. It should be noted that the same reference numerals are used for the portions corresponding to those in FIGS. 1 and 2.

As a restraint means for restricting the movement of the upper and lower rails 3 and 4 in the vertical direction (cylinder axis direction), a single projection 57 protruding from the lower surface of the upper rail 3 extends along the circumferential direction of the oil ring body 1. On the other hand, a single protrusion 50 protruding from the upper surface of the lower rail 4 is formed along the circumferential direction of the oil ring body 1, and the upper and lower protrusions 57, 5 are formed.
0s engage each other.

The upper protrusion 57 is integrally formed with a neck portion 51 projecting from the lower surface of the upper rail 3 and a head portion 52 bent from the tip of the neck portion 51. The head portion 52 and the neck portion 51 are bent with an L-shaped cross section.

The lower protrusion 50 is also bent with an L-shaped cross section to engage the head 52 of the upper protrusion 57 with a locking groove 58.
Is formed.

In the recess 54, a contact surface 55 for joining the head 52 of the projection 57 is formed in a plane shape orthogonal to the cylinder axis.

In the projection 57, a contact surface 59 for joining the contact surface 55 of the recess 54 is formed in a plane shape orthogonal to the cylinder axis.

The projection 57 and the engagement groove 58 engage with each other with a predetermined gap in the piston radial direction, and the upper and lower rails 3 and 4 can be independently displaced in the piston radial direction within the range of this gap.

With the above arrangement, the operation will be described.

When the oil ring main body 1 is assembled, the protrusion 57 of the upper rail 3 is fitted into the locking groove 58 of the lower rail 4 in a state where the joint of the upper rail 3 is wider than the joint of the lower rail 4. To engage from the radial direction, and each contact surface 55, 5
Join 9 together. As a result, the number of assembly steps can be reduced.

Also in this case, since the upper and lower rails 3 and 4 have the same cross-sectional shape in the circumferential direction, it is possible to form them by using the linear material having the same cross-sectional shape, which improves the productivity.

Further, the contact surface 55 of the recess 54 and the contact surface 59 of the projection 57 which are in sliding contact with each other may be provided with a surface layer made of a low wear material having a small friction coefficient.

In this case, the friction between the upper and lower rails 3 and 4 is reduced, the followability of the upper and lower rails 3 and 4 to the uneven portion of the cylinder inner wall is enhanced, and the amount of unlubricated oil left on the cylinder inner wall is further reduced. be able to.

[0073]

As described above, the invention according to claim 1 is a combination oil ring that includes an oil ring main body in which upper and lower rails are divided, and includes a coil spring that biases the oil ring main body in a radial direction. Since the upper and lower rails are provided with restraint means for restricting movement in the vertical direction, the friction between the upper and lower rails and the oil ring groove is reduced, the followability to the uneven portion of the cylinder inner wall of the upper rail is improved, and It is possible to reduce the amount of unlubricated oil left unlubricated and reduce the amount of lubricating oil consumed by the internal combustion engine.

The combined oil ring according to claim 2 is
In the invention according to claim 1, a plurality of protrusions protruding from the lower surface of the upper rail are formed as restraint means for restricting the movement of the upper and lower rails in the vertical direction, and the protrusions are recessed in the upper surface of the lower rail. By forming multiple locking grooves that engage the protrusions, the friction between the upper and lower rails and the oil ring groove is reduced, the followability to the uneven parts of the cylinder inner wall of the upper rail is improved, and the lubricating oil on the cylinder inner wall is left behind. The amount can be reduced to reduce the lubricating oil consumption of the internal combustion engine.

The combined oil ring according to claim 3 is
In the invention of claim 1, as a restraint means for restricting the movement of the upper and lower rails in the vertical direction, a single projection protruding from the lower surface of the upper rail is formed along the circumferential direction of the oil ring body, and the lower side Since a locking groove that is recessed in the upper surface of the rail and that engages the protrusion is formed along the circumferential direction of the oil ring main body, friction between the upper and lower rails and the oil ring groove is reduced, and the unevenness of the cylinder inner wall of the upper rail is reduced. It is possible to improve the followability to the portion and reduce the amount of unlubricated oil left on the cylinder inner wall to reduce the amount of lubricating oil consumed by the internal combustion engine.

The combined oil ring according to claim 4 is
In the invention according to claim 3, since the projection and the locking groove are formed in a T-shape in cross section, it is possible to form the upper and lower rails by using a linear material, which improves productivity and reduces cost. It comes off.

The combined oil ring according to claim 5 is
In the invention according to claim 3, since the cross-sectional shape of the protrusion is formed in an L shape, it is possible to form the upper and lower rails by using a linear material while reducing the number of assembling steps.
It can improve productivity and reduce costs.

The combined oil ring according to claim 6 is
In the invention according to any one of claims 1 to 5,
Since a surface layer made of a low wear material with a small coefficient of friction is formed on at least one of the contact surfaces that are in sliding contact with each other between the protrusion and the locking groove, friction between the upper and lower rails is reduced and the cylinder inner wall of the upper and lower rails is reduced. It is possible to improve the followability to the uneven portion of the above, further reduce the amount of the unlubricated oil left on the inner wall of the cylinder, and reduce the amount of lubricating oil consumed by the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a sectional view of an oil ring showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the oil ring of the same.

FIG. 3 is an exploded perspective view of an oil ring showing another embodiment.

FIG. 4 is a sectional view of an oil ring showing still another embodiment.

FIG. 5 is a sectional view of an oil ring and the like showing a conventional example.

FIG. 6 is a sectional view of an oil ring showing a conventional example.

[Explanation of symbols]

 1 Oil Ring Main Body 2 Coil Spring 3 Upper Rail 4 Lower Rail 6 Outer Peripheral Protrusion 7 Protrusion 8 Locking Groove 10 Outer Perimeter Protrusion 15 15 Contact Surface 18 Contact Surface 30 Piston 31 Oil Ring Groove 47 Protrusion 45 Contact Surface 48 Locking Groove 49 Contact surface 57 Protrusion 55 Contact surface 58 Locking groove 59 Contact surface

Claims (6)

[Claims] 1. A combination oil ring, comprising an oil ring main body having upper and lower rails divided, and a coil spring for urging the oil ring main body in a radial direction, wherein the upper and lower rails are restrained from moving in the vertical direction. A combination oil ring characterized by having means. 2. A plurality of projections projecting from the lower surface of the upper rail are formed as restraint means for restricting the movement of the upper and lower rails in the vertical direction, and the projections are recessed in the upper surface of the lower rail to engage the respective projections. The combination oil ring according to claim 1, wherein a plurality of locking grooves are formed. 3. As a restraint means for restraining the movement of the upper and lower rails in the vertical direction, a single protrusion protruding from the lower surface of the upper rail is formed along the circumferential direction of the oil ring body, and is formed on the upper surface of the lower rail. The combination oil ring according to claim 1, wherein a locking groove that is recessed in a concave shape and that engages the protrusion is formed along a circumferential direction of the oil ring body. 4. The combined oil ring according to claim 3, wherein each of the projection and the engaging groove has a T-shaped cross section. 5. The combined oil ring according to claim 3, wherein the projection has an L-shaped cross section. 6. A surface layer made of a low wear material having a small friction coefficient is formed on at least one of the contact surfaces that are in sliding contact with each other between the projection and the locking groove. The combination oil ring described in one.