JP2009156183A - Engine seal structure, resin ring, and engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal structure for an engine, a resin ring, and an engine which are less influenced by cavitations. <P>SOLUTION: A seal structure to be attached to a cylinder liner 1 of a water-cooled engine comprises a back-up ring 4 facing a water jacket 3 formed between this cylinder liner 1 and a cylinder block 2, in which the back-up ring 4 is formed of a thermoplastic resin, is cut at a cutting part in the circumferential direction. The cutting part is arranged at a place out the engine thrust direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine seal structure, a resin ring, and an engine, and more particularly to an engine seal structure, a resin ring, and an engine used in a water jacket portion formed between a cylinder liner and a cylinder block in a water-cooled engine. The present invention relates to an engine to which the seal structure is applied.

  Conventionally, in a water-cooled engine, cooling water for engine cooling circulates between a radiator and a water jacket formed between a cylinder block and a cylinder liner. The cylinder liner is provided with a square seal ring for preventing leakage of the cooling water (Patent Document 1).

Japanese Utility Model Publication No. 4-117166

  By the way, in recent years, the present inventor has found that, as the engine output increases and the in-cylinder pressure increases, vibration in the thrust direction of the piston causes a large pressure vibration in the cooling water in the water jacket, resulting in cavitation. It was. Therefore, in the conventional seal structure, there is a possibility that the rectangular seal ring facing the cooling water is damaged by cavitation and leakage of the cooling water occurs.

  An object of the present invention is to provide an engine seal structure, a resin ring, and an engine that can be hardly affected by cavitation.

An engine seal structure according to claim 1 of the present invention is a seal structure that is mounted on a cylinder liner of a water-cooled engine and has a resin ring facing a water jacket formed between the cylinder liner and a cylinder block. The resin ring is formed of a thermoplastic resin and is cut in the circumferential direction by a cutting portion, and the cutting portion is located away from the engine thrust direction. .
Here, the “engine thrust direction” refers to a direction orthogonal to the axial direction of the crankshaft and the axial direction of the cylinder liner.

The engine seal structure according to claim 2 of the present invention is the engine seal structure according to claim 1, wherein a rubber seal ring is in contact with the resin ring on the side opposite to the side facing the water jacket. It is characterized by being.
Here, “contact” means that the resin ring and the seal ring are not in contact with each other, but the resin ring and the seal ring may be bonded with an adhesive or the like, or may be integrally formed. Including.

  The engine seal structure according to claim 3 of the present invention is the engine seal structure according to claim 1 or 2, wherein the cylinder liner is press-fitted into the cylinder block and the resin ring is mounted. A recess is provided along the circumferential direction, a round corner is provided in the recess, and the resin ring has a chamfered portion in the outer peripheral portion on the front side in the press-fitting direction of the cylinder liner in the press-fitting direction. A curved surface portion is provided in each inner peripheral portion on the rear side, and the curved surface portion of the resin ring is in close contact with the corner portion in the recess.

  The engine seal structure according to a fourth aspect of the present invention is the engine seal structure according to any one of the first to third aspects, wherein the cut surface formed by being cut by the cutting portion is the cylinder liner. It is formed so as to intersect with at least one of the axial direction and the radial direction.

  An engine seal structure according to a fifth aspect of the present invention is the engine seal structure according to any one of the first to fourth aspects, wherein the engine seal structure deviates from a range of 30 ° in the circumferential direction with respect to the engine thrust direction. The cutting part is located.

  The resin ring which concerns on Claim 6 of this invention is used for the engine seal structure in any one of Claims 1-5.

  An engine according to claim 7 of the present invention is characterized in that the engine seal structure according to any one of claims 1 to 5 is employed.

  In the above, according to the first and sixth and seventh aspects of the present invention, the resin ring has a low elasticity and is formed of a harder thermoplastic resin than that of rubber, so that it occurs in the water jacket. There is no risk of damage due to cavitation. Moreover, since the resin ring is hard, the mounting property to the cylinder liner becomes a problem, but since the middle of the resin ring in the circumferential direction is cut, it is also made of a hard thermoplastic resin. Regardless, the resin ring can be easily mounted on the cylinder liner. Furthermore, by positioning the cutting portion away from the engine thrust direction where cavitation is likely to occur, the cutting portion can avoid the influence of cavitation, and cavitation does not affect the other through the cutting portion.

  According to the second aspect of the present invention, since the seal ring does not face the water jacket by disposing the seal ring at a position opposite to the side facing the water jacket of the resin ring, the seal ring enters the water jacket. It can be prevented from protruding. Furthermore, the use of a rubber seal ring with high elasticity can reliably prevent leakage of cooling water. Further, by disposing the cut portion of the resin ring at a position where the influence of cavitation is small, the seal ring can be prevented from being damaged without being affected by the cavitation from the cut portion.

  According to the invention of claim 3, since the chamfered portion is provided in the resin ring, when the cylinder liner with the resin ring is press-fitted into the cylinder block, the resin ring is smoothly caught without being caught by the water jacket. Can be pushed into. In addition, since the resin ring has a curved surface portion, the resin ring can be satisfactorily held in the concave portion by bringing the curved surface portion into close contact with the corner portion in the concave portion of the cylinder liner in a state where the cylinder liner is press-fitted. .

  According to the fourth aspect of the present invention, since the cut surface intersects at least one of the axial direction and the radial direction of the cylinder liner, the progress of cavitation can be blocked at the cut surface, The influence of cavitation can be prevented.

  According to the fifth aspect of the present invention, cavitation is particularly likely to occur in the engine thrust direction. However, since the cutting portion is located outside the range of 30 ° forward and backward from the engine thrust direction, the cavitation to the cutting portion is The impact can be avoided reliably. Therefore, even if the cut portion is formed in the resin ring, it is possible to more reliably prevent the influence of cavitation from being exerted through the cut portion.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a water-cooled engine 10 to which the seal structure in the present embodiment is applied, and FIG. 2 is a cross-sectional view showing the main part of the seal structure. FIG. 3A is a perspective view of the backup ring 4 as a resin ring constituting the seal structure, and FIG. 3B is a front view of the backup ring 4. 4 is a cross-sectional view of the cylinder block 2 taken along line IV-IV in FIG.

  1 and 2, a water jacket 3 for cooling the engine is formed between the cylinder liner 1 and the cylinder block 2 of the water-cooled engine 10 so as to surround the outer periphery of the cylinder liner 1. The inside of the cylindrical cylinder liner 1 is a cylinder space 11 in which a piston (not shown) reciprocates. A plurality of concave portions 12 that are continuous in the circumferential direction are provided on the outer periphery of the cylinder liner 1 at predetermined intervals. ing.

  In the recess 12 on the uppermost side (cylinder head side), the backup ring 4 is arranged on the upper side, and the rectangular seal ring 5 as a seal ring is arranged on the lower side, and the rubber seal 6 is arranged in the other recess 12. . Further, cooling water 31 for engine cooling circulates in the water jacket 3 with a radiator (not shown).

  Here, the backup ring 4 is made of a thermoplastic resin having low elasticity and excellent heat resistance and water resistance. Such a backup ring 4 is used to prevent the square seal ring 5 from protruding to the water jacket 3 side, and to reduce the influence of cavitation on the square seal ring 5. However, the material is hardly affected by cavitation.

  As the material of the backup ring 4, polytetrafluoroethylene is adopted in the present embodiment, but is not limited thereto, polyethylene, polypropylene, polystyrene, acrylotolyl, butanediene, styrene resin, polyvinyl chloride, acrylonitrile, Styrene resin, methacrylic resin, vinyl chloride, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, GF reinforced polyethylene terephthalate, ultrahigh molecular weight polyethylene, polyphenylene sulfide, polyimide, polyetherimide, polyarylate, polysulfone, polyethersulfone Any of thermoplastic resins such as polyetheretherketone and liquid crystal polymer may be arbitrarily adopted in consideration of heat resistance.

  The square seal ring 5 is made of a synthetic rubber having elasticity, and is formed to have an outer diameter having a crushing allowance that is crushed by the wall surface 21 of the cylinder block 2 in a state of being accommodated in the recess 12. Such a square seal ring 5 is used to prevent the cooling water 31 from leaking to the lower side of the cylinder block 2 (the side opposite to the cylinder head). The rubber seal 6 prevents lubricating oil from entering the square seal ring 5 from the lower side of the cylinder block 2 and is made of a synthetic rubber having elasticity.

  Referring to FIG. 2, the cross-sectional shape of the space 121 formed by the recess 12 and the wall surface 21 of the cylinder block 2 becomes narrower in a wedge shape as it goes downward. According to this, when the cylinder liner 1 is press-fitted into the cylinder block 2 after placing the backup ring 4 and the square seal ring 5 in the recess 12 (in the direction of the white arrow in FIG. 2), the square seal ring 5 The portion is pressed and compressed by the wall surface 21, and is in close contact with the space 121, thereby reliably preventing the cooling water 31 from leaking.

  That is, when the cylinder liner 1 is press-fitted to a position where it abuts on the stepped portion 23 (FIG. 1) of the cylinder block 2, the square seal ring 5 is compressed while being pressed against the wall surface 21, so It adheres and prevents the leakage of the cooling water 31 reliably. Further, the square seal ring 5 presses the backup ring 4 by a reaction force from the wall surface 21. When the backup ring 4 is pressed by the square seal ring 5, the curved surface portion 43 provided on the inner peripheral side of the backup ring 4 adheres well to the round-shaped corner portion 122 provided in the recess 12, and is more stable. Is held in the state.

Next, the shape and arrangement direction of the backup ring 4 will be described.
As shown in FIGS. 3A and 3B, a cutting portion 41 is provided in the middle of the backup ring 4 in the circumferential direction. The backup ring 4 is cut by the cutting portion 41 at an appropriate angle with respect to the axial direction of the cylinder liner 1 when viewed from the front. That is, the cut surface 44 is cut so as to intersect the axial direction of the cylinder liner 1. By cutting one part of the backup ring 4, the backup ring 4 having a small elasticity can be easily mounted in the recess 12 while being widened. In FIG. 3 (A), the backup ring 4 is shown open so that the cut surface 44 can be seen.

  As shown in FIGS. 3A and 2, a chamfered portion 42 that is continuous in the circumferential direction is formed on the lower outer peripheral portion of the backup ring 4 that is the front side of the cylinder liner 2 in the press-fitting direction. On the upper inner peripheral portion of the backup ring 4 on the rear side in the press-fitting direction, the above-described curved surface portion 43 that is continuous in the circumferential direction is formed. The chamfered portion 42 eliminates the catch on the corner portion 22 provided on the cylinder block 2 side during the press-fitting, so that the backup ring 4 is smoothly pushed. The chamfered portion 51 provided on the square seal ring 5 operates in the same manner. The curved surface portion 43 comes into close contact with the corner portion 122 in the recess 12 when the cylinder liner 1 is press-fitted into the cylinder block 2.

  Referring to FIG. 4, when the backup ring 4 is mounted on the cylinder liner 1, the cutting portion 41 is orthogonal to the engine thrust direction (both the axial direction of the crankshaft (not shown) and the axial direction of the cylinder liner 1). It is located away from the direction. In the present embodiment, the cutting portion 41 is located at a position shifted by 90 ° in the circumferential direction from the engine thrust direction, that is, corresponding to the axis AA of the crankshaft.

  In the engine thrust direction, cavitation is likely to occur in the water jacket 3 due to the vibration generated by the reciprocating motion of the piston. For this reason, if the cutting part 41 is positioned in the engine thrust direction affected by cavitation, the rectangular seal ring 5 positioned below from the cut end of the cutting part 41 may be affected by cavitation. That is, in this embodiment, the cutting part 41 is positioned away from the engine thrust direction, thereby eliminating the influence of cavitation on the rectangular seal ring 5 via the cutting part 41. Here, it is sufficient that the position of the cutting portion 41 is deviated from the engine thrust direction. However, it is preferable that the position of the cutting portion 41 is deviated from the front and rear 30 ° in the circumferential direction with respect to the engine thrust direction. As in the embodiment, it is preferable to correspond to the axis AA of the crankshaft.

Note that the present invention is not limited to the above-described embodiment, and includes other configurations that can achieve the object of the present invention, and includes the following modifications and the like.
For example, in the above-described embodiment, the backup ring 4 is cut obliquely in a state viewed from the front by the cutting portion 41, but may be cut vertically in the drawing along the axial direction of the cylinder liner 1. This also facilitates mounting on the cylinder liner 1, and the rectangular seal ring 5 is not affected by cavitation via the cutting portion 41 by removing the engine thrust direction and positioning the cutting portion 41.

  In the above-described embodiment, the backup ring 4 and the square seal ring 5 are separate from each other and are simply in contact with each other. However, the backup ring 4 and the square seal ring 5 may be bonded to each other with an adhesive or the like. The seal ring 5 may be integrally formed. Even in these cases, only the portion corresponding to the backup ring 4 is broken, so that it can be easily mounted on the cylinder liner 1 without being affected by cavitation as described above.

  Further, the shape of the cutting portion 41 may be a shape as shown in FIGS. The backup ring 4 in FIGS. 5A and 5B is cut into a crank shape in plan view by the cutting portion 41, and the backup ring 4 in FIGS. 6A and 6B is flat by the cutting portion 41. It is cut obliquely with respect to the radial direction when viewed. Also in these cases, the backup ring 4 has a cut surface that intersects the radial direction of the cylinder liner 1. Further, the backup ring 4 in FIG. 5 is cut in a crank shape in a plan view, but may be cut in a crank shape in a front view. In this case, it has a cut surface that intersects the axial direction of the cylinder liner 1.

  In the above-described embodiment, the cutting portion 41 is disposed at a position where the engine thrust direction is removed, but FIG. 7 shows a case where the cutting portion 41 is positioned in the engine thrust direction as a reference. The backup ring 4 in this case is, for example, whether it is cut obliquely or cut in a crank shape by the cutting portion 41 in a plan view or a front view. That is, the backup ring 4 may not be cut so that the cut surface formed by the cutting portion 41 intersects the axial direction or the radial direction of the cylinder liner 1. If the cut surface at the cutting portion 41 is along the axial direction or the radial direction of the cylinder liner 1, the influence of the generated cavitation exerts on the lower rectangular seal ring 5 through the cutting portion 41.

  On the other hand, if the cut surface at the cutting portion 41 is slanted as described above or is crank-shaped, it proceeds along the axial direction or the radial direction of the cylinder liner 1 or the outer peripheral side of the backup ring 4. It is possible to block the damage caused by cavitation that tends to proceed toward the inner peripheral side from the cut surface, and to reduce the influence of cavitation that the square seal ring 5 receives. Therefore, even when the cutting portion 41 is disposed in the engine thrust direction where cavitation is likely to occur, the rectangular seal ring 5 is prevented from being damaged due to the influence of cavitation, and the leakage of the cooling water 31 can be prevented. In addition, since the cutting portion 41 is provided, the square seal ring 4 can be easily attached.

  The present invention can be suitably used for preventing leakage of cooling water filled in a water jacket of a water-cooled engine.

A sectional view showing an important section of a water cooling engine to which a seal structure concerning one embodiment of the present invention was applied. Sectional drawing which shows the principal part of the said seal structure. The perspective view and front view which show the backup ring which comprises the said seal structure. Sectional drawing of the cylinder block in the IV-IV line of FIG. The perspective view and top view which show the backup ring of a modification. The perspective view and top view which show the backup ring of a modification. Sectional drawing of the cylinder block which shows the modification about the arrangement | positioning direction of the cutting part of a backup ring.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cylinder liner, 2 ... Cylinder block, 3 ... Water jacket, 4 ... Backup ring as resin ring, 5 ... Square seal ring as seal ring, 10 ... Water-cooled engine, 12 ... Recessed part, 31 ... Cooling water, 41 ... cutting part, 42 ... chamfering part, 43 ... curved surface part, 44 ... cutting surface, 122 ... corner part.

Claims (7)

A seal structure having a resin ring mounted on a cylinder liner of a water-cooled engine and facing a water jacket formed between the cylinder liner and a cylinder block,
The resin ring is formed of a thermoplastic resin, and the middle in the circumferential direction is cut by a cutting portion,
The engine sealing structure according to claim 1, wherein the cutting portion is located away from an engine thrust direction. The engine seal structure according to claim 1,
A seal structure for an engine, wherein a rubber seal ring is in contact with the resin ring on a side opposite to the side facing the water jacket. The engine seal structure according to claim 1 or 2,
The cylinder liner is press-fitted into the cylinder block, and a recess in which the resin ring is mounted is provided along the circumferential direction.
A round corner is provided in the recess,
The resin ring is provided with a chamfered portion on the outer peripheral portion on the front side in the press-fitting direction of the cylinder liner, and a curved surface portion on the inner peripheral portion on the rear side in the press-fit direction,
An engine seal structure, wherein a curved surface portion of the resin ring is in close contact with a corner portion in the recess. The engine seal structure according to any one of claims 1 to 3,
The engine sealing structure, wherein a cut surface formed by being cut by the cutting portion is formed so as to intersect at least one of an axial direction and a radial direction of the cylinder liner. The engine seal structure according to any one of claims 1 to 4,
The engine sealing structure characterized in that the cutting portion is located outside a range of 30 ° in the circumferential direction with respect to the engine thrust direction. It is used for the engine seal structure in any one of Claims 1-5. The resin ring characterized by the above-mentioned. The engine seal structure according to any one of claims 1 to 5 is adopted. An engine characterized by things.

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