JP2002039154A - Mounting structure for thrust metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate application of unnecessary moment toward a crankshaft 10 to thrust metals 34F and 34R following the rotation of the crankshaft 10. SOLUTION: Semicircular arc thrust grooves 28F along the peripheral edge of a journal bore 22 are formed in both axial side surfaces 16F of a bulk part 16C of a cylinder block and a bearing cap fastened with it. Both side surfaces of the bulk part 16C are provided with lock grooves 32F extending radially outwardly from the downstream side end of the thrust grooves with respect to the rotation direction α of the crankshaft 10. Projections 36F and 36R engaging with the lock grooves are disposed at the downstream side ends with respect to the rotation direction α in the semicircular arc thrust metals 34F and 34R engaging with the thrust grooves in the bulk part 16C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust metal mounting structure for receiving a thrust force of a crankshaft of an internal combustion engine.

[0002]

2. Description of the Related Art Generally, a crank journal of a crankshaft of an internal combustion engine is rotatably supported by a half-type journal bore formed in a mating surface between a bulk portion of a cylinder block and a bearing cap fixed to each other. Is done. A thrust groove is formed along the peripheral edge of the journal bore on both axial sides of at least the pair of bulk portions and the bearing cap.
A thrust metal that receives the thrust force of the crankshaft is attached.

As an example, Japanese Patent Application Laid-Open No. 05-306710 discloses a technique in which two half-type thrust metals are used on each side in the axial direction, that is, a total of four thrust metals are used on both sides. In the case of this four-piece structure, since the thrust grooves formed in both the cylinder block and the bearing cap have an annular shape as a whole, the thrust grooves are provided with the bearing cap fastened to the cylinder block. Therefore, there is an advantage that the accuracy such as the perpendicularity of the thrust groove with respect to the axis of the journal bore can be easily obtained. However, there are problems such as an increase in the number of parts, an increase in cost, and an increase in the amount of assembly work.

[0004] As another example, it is known that a flange portion corresponding to the above-described thrust metal is integrally formed at both axial ends of a main metal attached to a journal bore. However, in this case, the structure becomes complicated. , Again, disadvantageous in terms of cost.

Therefore, in order to mainly reduce the cost, a technique of reducing the number of half-type thrust metals to two for a pair of cylinder blocks and bearing caps has been known (see, for example, Japanese Patent Application Laid-Open No. H11-163873). See Japanese Utility Model Application Laid-Open No. 64-57416). In this configuration, generally, the thrust groove is formed only on the cylinder block side, the thrust groove is not formed on the bearing cap, the thrust metal end face is pressed by the mating surface of the bearing cap, and the thrust metal is stopped. It is designed to prevent rattling.

However, when there is no thrust groove on the bearing cap side, the thrust groove cannot be machined with the bearing cap fastened to the cylinder block side as described above. For this reason, the processing accuracy of the thrust groove is reduced. In other words, since the thrust groove is machined without the bearing cap being fastened to the cylinder block side, when the bearing cap is finally fastened and fixed to the cylinder block, the vicinity of the thrust groove is inevitable due to bolt axial force etc. It may expand (expand) in the axial direction, possibly inviting local contact of the thrust metal.

Therefore, in Japanese Unexamined Patent Publication No. 11-108038, as shown in FIG.
A technique is disclosed in which the thrust metal 7 is reduced to two sheets on both side surfaces while forming 6. That is, a claw 7c for preventing rotation is provided at one end of the thrust metal 7 having a substantially semicircular arc shape, and the claw 7c is engaged with a claw groove 8 formed in the cylinder block 1 so that the thrust metal 7 is formed. While stopping the rotation, the other end of the thrust metal 7
An extension 7b extending into the thrust groove 5 of the bearing cap 3 is set to prevent the thrust metal 7 from rattling.

[0008]

However, as shown in FIG. 4 of Japanese Patent Application Laid-Open No. H11-108038, in order to mainly simplify the manufacturing, generally, all the thrust metal 7 is made up and down. Are formed in the same defined shape.
When such thrust metal 7 having the same shape is attached to both axial side surfaces of the cylinder block 1, at least one axial side surface has a claw 7 as shown in FIG.
c is located upstream with respect to the rotation direction β of the crankshaft. In this case, with the rotation of the crankshaft, a moment M1 acts on the thrust metal 7 in a direction toward the crankshaft with the engagement portion between the claw 7c and the claw groove 8 as a fulcrum. For this reason, the thrust metal 7 easily inadvertently interferes with the crankshaft, and as a result, the thrust metal 7 tends to fall off and be entangled in the crankshaft.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems. That is, the invention according to claim 1 can rotate the crank journal of the crankshaft on the mating surface between the bulk portion of the cylinder block and the bearing cap fixed to each other in the mounting structure of the thrust metal receiving the thrust force of the crankshaft. A half-type journal bore is formed to support the
At least a pair of bulk portions and a semicircular thrust groove are formed on both sides in the axial direction of the bearing cap along the peripheral edge of the journal bore, respectively.
On both sides of the bulk portion, detent grooves projecting radially outward from the downstream end of the thrust groove in the rotation direction of the crankshaft are formed, and the thrust metal fits into the thrust groove of the bulk portion. It is characterized in that it has a semicircular shape that fits, and a projection that fits into the detent groove is provided at the downstream end in the rotation direction of the crankshaft.

Further, according to the present invention, a main metal which is in sliding contact with the outer periphery of a crank journal of the crankshaft is attached to the journal bore of the bulk portion, and the axial dimension of the main metal is adjusted to the bulk portion. It is characterized in that it is set larger than the axial dimension of the portion where the thrust groove is formed.

According to a third aspect of the present invention, the shape of the pair of detent grooves formed on both sides in the axial direction of the bulk portion is different from each other, and the pair of main metal fittings respectively fitted in the detent grooves. It is characterized in that the shapes of the projections are different from each other.

That is, even if the front main metal is to be assembled into the rear thrust groove, the projection does not properly fit into the detent groove, so that an incorrect assembly of the main metal can be reliably performed. Can be suppressed.

[0013]

According to the first aspect of the present invention, the number of thrust metals can be reduced to two for a pair of bulk portions and a bearing cap. A small number of points are required, which is advantageous in terms of cost.

In addition, the thrust groove is formed in both the bulk portion and the bearing cap while adopting the two-piece structure as described above, and the thrust groove is formed over the entire circumference. Therefore, it is possible to perform the thrust groove in the state where the bearing cap is fastened to the bulk portion, and the processing accuracy of the thrust groove is improved. On the other hand, when the thrust groove is formed only on one of the bulk portion and the bearing cap, such a process cannot be performed. The deformation of the thrust groove due to the axial force cannot be avoided, the processing accuracy is reduced, and the thrust metal may be locally hit.

Furthermore, since no thrust metal is present in the thrust groove of the bearing cap and a space is left, the thrust groove is also advantageous in terms of radiating heat generated in the bearing portion.

In addition, since the projection of each thrust metal is fitted into the detent groove of the thrust groove, the end face of the projection and the mating surface of the bearing cap come into contact with and engage with each other. The rotation of the thrust metal used for the rotation of the shaft can be prevented.

The projection and the detent groove having the thrust metal detent function are arranged on the downstream side with respect to the rotation direction of the crankshaft. For this reason, the moment acting on the thrust metal with the rotation of the crankshaft is directed in a direction away from the crankshaft with the projection as a fulcrum, in both the axial metal side thrust metal. There is no moment acting in the direction toward. For this reason, there is no possibility that an unnecessary load acts on the crankshaft side or that the thrust metal falls off or gets caught in the crankshaft.

According to the second aspect of the present invention, the main metal effectively prevents the thrust metal from falling off to the inner diameter side and rattling in the radial direction.

According to the invention of claim 3, erroneous assembly of the main metal can be reliably suppressed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a thrust metal mounting structure according to the present invention is applied to an in-line four-cylinder internal combustion engine will be described in detail with reference to FIGS. 3 is an enlarged view of a portion C in FIG. 2, FIG. 4 is a view corresponding to an arrow A in FIG. 2, and FIG. 5 is a view corresponding to an arrow B in FIG.

The crankshaft 10 is provided with crank journals 12 coaxially with the rotation axis 11 at a total of five places between the cylinders and at both ends of the cylinder rows. On the other hand, the bulk portion 16 of the cylinder block 14
Bearing cap 18 having substantially the same axial dimension as
Are fixed from below by bolts (not shown), and the mating surfaces of the two are half-split (total circular) that rotatably support the crank journal 12.
Journal bores 22, 24 are formed respectively.

Each of the journal bores 22 and 24 is provided with a semi-cylindrical (as a whole, cylindrical) main metal 26 which is in sliding contact with the outer peripheral surface of the crank journal 12. Each main metal 26 has a chamfered portion 2 on the inner peripheral side.
6a (FIG. 3) are formed, and are preferably formed in the same shape in order to reduce manufacturing costs. Although not shown, each main metal 26 and bulk portion 16,
The bearing cap 18 is provided with claws, grooves, and the like for preventing relative movement between the two.

Here, a pair of bulk portions 16C and a bearing cap 18C, which are located substantially at the center of the cylinder row, are provided on both axial sides, that is, axial front surfaces 16F, 18F and rear surface 16F.
In the R and 18R, thrust grooves 28F, 28R, 30F and 30R each forming a semicircular arc shape (total annular shape) are respectively recessed at four places along the peripheral edges of the journal bores 22 and 24.

As shown in FIGS. 4 and 5, the front face 16F and the rear face 16R of the bulk portion 16C have thrust grooves 28F, 28R with respect to the rotation direction α of the crankshaft 10.
Rotation-stop grooves 32F and 32R projecting radially outward from the downstream end of R are respectively recessed. The detent grooves 32F, 32R are formed at substantially the same depth as the thrust grooves 28F, 28R.

Then, only in the thrust grooves 28F and 28R of the bulk portion 16C, the semicircular thrust metal 34F, which receives the thrust surface 10a of the crankshaft 10, is provided.
34R are respectively fitted and arranged.

FIGS. 6 and 7 show the front thrust metal 34F and the rear thrust metal 34R, respectively, and show the surface sides of the crankshaft 10 facing the thrust surface 10a. Protrusions 36F, 36R fitted to the detent grooves 32F, 32R, respectively, are provided at the downstream ends of the thrust metals 34F, 34R that are downstream with respect to the rotation direction α of the crankshaft 10 in the assembled state. Are formed to protrude radially outward. That is, the formation positions of the protrusions 36F, 36R are different between the two thrust metals 34F, 34R.

In order to prevent the front and rear thrust metals from being mistakenly assembled at the time of assembly, the projection 36F of the front thrust metal 34F and the rear thrust metal 34R
The shape of the protrusion 36R is different from that of the protrusion 36R. Accordingly, the shapes of the detent grooves 32F and 32R are also different from each other.

In order to ensure lubricity, two lubricating oil grooves 42F, 42R are provided on the side surfaces (the side surfaces shown in FIGS. 6 and 7) of the respective thrust metals 34F, 34R which are in sliding contact with the thrust surface 10a. Are formed respectively.

Further, tapered portions 38F, 38R which are gradually thinned toward both ends are formed at both ends of each of the thrust metals 34F, 34R so as to absorb axial displacement.

In addition, each thrust metal 34F, 34R
Notches 40F and 40R are respectively formed on the inner peripheral side of both ends of the main body to mainly improve the efficiency of material removal during manufacturing.

According to the mounting structure of this embodiment, the thrust grooves 28F, 30F, and 28
Since R and 30R are formed over the entire circumference, in a state where the bearing cap 18 is fastened to the bulk portion 16,
Like the journal bores 22 and 24, the thrust grooves can be machined. Therefore, the processing accuracy of the thrust groove is improved, and the local contact of the thrust metal as in the above-described conventional example can be reliably suppressed.

Further, since the thrust metal 34F, 34R is mounted on the pair of bulk portions 16 and the bearing cap 18 one by one at the front and the rear, the thrust metal 34F, 34R is compared with the conventional four-plate structure. Therefore, the number of parts can be reduced, which is advantageous in terms of cost. In addition, since no thrust metal is provided in the thrust grooves 30F and 30R of the bearing cap 18, the thrust grooves 30F and 30R are not provided.
R is left as a space, and heat is radiated through the lubricating oil in this space, which is advantageous in terms of heat radiation of heat generated in the bearing portion.

Further, the protrusions 36 are formed in the detent grooves 32F, 32R projecting outward from the thrust grooves 28F, 28R.
F, 36R are fitted, so that the projections 36F, 36R
The end face of R and the mating surface of the bearing cap 18 abut,
By the engagement, the rotation of the thrust metal 34F, 34R, which is used for the rotation of the crankshaft 10, can be prevented.

Then, such a thrust metal 34
Projections 36F, 36 having a function of preventing rotation of F, 34R
The R and the detent grooves 32F, 32R are disposed downstream with respect to the rotation direction α of the crankshaft 10. For this reason, the projections 36 are provided on the thrust metals 34F and 34R.
A moment M2 acts in a direction away from the crankshaft 10 with the F and 36R as fulcrums. The moment M2 is applied to the inner peripheral surfaces of the thrust grooves 28F and 28R which abut and engage with the outer peripheral surfaces of the thrust metals 34F and 34R. It is reliably received by the surface.

In other words, with the rotation of the crankshaft 10, the thrust metal 34F, 34R gives a moment in the direction toward the crankshaft 10 (M1 in FIG. 8).
Does not act, an unnecessary load acts on the crankshaft 10 side, and the thrust metals 34F, 34R fall off or the crankshaft 10
There is no danger of being involved in the side.

Further, in the present embodiment, as shown in FIG. 3, the axial dimension D1 of the main metal 26 is
6 is set to be larger than the axial dimension D2 of the portion where the thrust grooves 28F and 28R are formed, and the main metal 26 allows the thrust metals 34F and 34R to be formed.
Is effectively prevented from dropping to the inner diameter side and rattling in the radial direction.

The axial dimension D1 of the main metal 26 is set smaller than the axial dimension D3 between the opposing thrust surfaces 10a so that the main metal 26 does not interfere with the thrust surface 10a of the crankshaft 10. Have been.

In the above-described embodiment, the bearing caps 18 are five independent bearing caps. Alternatively, a type in which a plurality of bearing caps are connected by a connecting member may be used. Also,
A so-called ladder frame type bearing cap in which all the bearing caps are integrated including the outer wall of the engine body may be used.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a thrust metal mounting structure according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the mounting structure of the embodiment.

FIG. 3 is an enlarged view of a portion C in FIG. 2;

4 is a view corresponding to an arrow A in FIG. 2 and shows a mounting structure of a front-side thrust metal according to the present embodiment.

FIG. 5 is a view corresponding to an arrow B in FIG. 2 showing a mounting structure of the rear thrust metal of the embodiment.

FIG. 6 is a front view of a front thrust metal according to the embodiment.

FIG. 7 is a front view of the rear thrust metal of the embodiment.

FIG. 8 is a front view showing a conventional thrust metal mounting structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Crankshaft 14 ... Cylinder block 16 ... Bulk part 18 ... Bearing cap 22, 24 ... Journal bore 26 ... Main metal 28F, 28R, 30F, 30R ... Thrust groove 32F, 32R ... Detent groove 34F, 34R ... Thrust metal 36F , 36R ... Protrusion

Claims (3)

[Claims] 1. A mounting structure for a thrust metal receiving a thrust force of a crankshaft, wherein a half of a crank journal of a crankshaft is rotatably supported on a mating surface between a bulk portion of a cylinder block and a bearing cap fixed to each other. A semi-circular thrust groove is formed along the peripheral edge of the journal bore on at least the two axial side surfaces of the pair of bulk portions and the bearing cap, respectively.
On both sides of the bulk portion, detent grooves projecting radially outward from the downstream end of the thrust groove with respect to the rotation direction of the crankshaft are formed. The thrust metal fits into the thrust groove of the bulk portion. A thrust metal mounting structure comprising a semicircular arc that fits and a projection that fits into the detent groove is provided at a downstream end in a rotation direction of the crankshaft. 2. A main metal, which is in sliding contact with an outer periphery of a crank journal of the crankshaft, is attached to a journal bore of the bulk portion, and an axial dimension of the main metal is formed with a thrust groove of the bulk portion. The thrust metal mounting structure according to claim 1, wherein the size is set larger than the axial dimension of the portion. 3. The shape of a pair of detent grooves formed on both sides in the axial direction of the bulk portion is different from each other, and the shape of a pair of main metal protrusions respectively fitted into the detent grooves is changed. The thrust metal mounting structure according to claim 1, wherein the thrust metal mounting structures are different from each other.