JP2013117200A - Internal combustion engine, method for manufacturing the same, and vehicle mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine that can reduce piston friction and reduce piston slap with a simple structure, and to provide a method for manufacturing the same and a vehicle mounting the same.SOLUTION: Grooves 11a and 11b extending in a reciprocating direction of a piston 3 are provided in such a way that at least a thrust side and a side opposite thereto on an outer peripheral surface of a skirt 3a of the piston 3 which reciprocates in a cylinder liner 2 do not come into directly contact with a thrust surface 2a and a counter-thrust surface 2b. In addition, a plurality of steel balls 12a coming into rolling contact with the thrust surface 2a and a plurality of steel balls 12b coming into rolling contact with the counter-thrust surface 2b are arranged in an extending direction of the grooves 11a and 11b, respectively.

Description

  The present invention relates to an internal combustion engine that can reduce piston clearance, reduce piston slap, and reduce piston friction, a manufacturing method thereof, and a vehicle equipped with the same.

  A gap (hereinafter referred to as piston clearance) is provided between the piston of the engine (internal combustion engine) and the cylinder liner to facilitate the reciprocating motion of the piston. However, with this piston clearance, the in-cylinder pressure due to absorption, compression, combustion, and exhaust stroke of the piston, the inertia of the piston itself, and the crankshaft connected to the piston are converted from reciprocating motion to rotational motion. The thrust force due to the effect acts on the piston, and a swing motion (hereinafter referred to as piston slap) around the piston pin occurs. As a result, a slap noise, which is one of the causes of engine noise, is generated, and piston friction increases due to contact between the piston and the cylinder liner.

  Here, a conventional piston will be described with reference to FIG. As shown in FIG. 8A, the engine 1X includes a cylinder liner 2 and a piston 3X that reciprocates therein. A connecting rod 4 connected to a crankshaft (not shown) is connected to the piston 3X via a piston pin 5. A piston clearance CL is provided between the piston 3X and the cylinder liner 2.

  As described above, the piston 3 generates the thrust force Tf generated by the change in the cylinder pressure, the inertia of the piston 3 itself, and the action of the crank mechanism including the connecting rod 4 and the crankshaft, which is orthogonal to the axial direction of the piston pin 5. Receive in the direction. Then, the piston 3X tilts, the ring 6 (6a, 6b, 6c) of the piston 3X comes into contact with a thrust side surface (hereinafter referred to as a thrust surface) 2a of the cylinder liner 2, and the skirt portion 3aX of the piston 3X is in contact with the cylinder liner. 2 is in contact with an anti-thrust surface (hereinafter referred to as an anti-thrust surface) 2b.

  Alternatively, as shown in FIG. 8B, the piston 3X is pressed against the thrust surface 2a of the cylinder liner 2, and the ring 6 and the skirt portion 3aX of the piston 3 come into contact with the thrust surface 2a. The movement of the piston 3 due to the action of the thrust force is the piston slap, and a slap sound is generated due to this. At this time, the piston skirt 3a or the ring 6 comes into contact with the thrust surface 2a or anti-thrust surface 2b of the cylinder liner 2 to increase piston friction.

  In order to solve the above problem, there is an apparatus in which rolling bearings that can roll along the piston sliding surface of the cylinder are provided rotatably on the thrust side and the anti-thrust side of the skirt (see, for example, Patent Document 1). ). According to this apparatus, piston friction between the piston and the cylinder liner can be reduced, so that piston seizure and scuffing can be prevented.

  However, the above-mentioned device has a problem that it is necessary to provide a rolling bearing in the skirt portion of the piston, the structure is complicated, and pressure is concentrated on the contact portion between the rolling bearing and the cylinder liner. In addition, the rolling bearing of the above-described device is only in the reciprocating direction of the piston, so when a force other than the direction in which the thrust force is applied is applied, that is, when a force from a direction other than the rolling direction of the rolling bearing is applied. There is also a problem that the rolling bearing is broken.

JP 2004-144014 A

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the piston clearance, reduce the piston slap and reduce the piston friction with a simple structure, The manufacturing method and a vehicle equipped with the manufacturing method are provided.

  An internal combustion engine of the present invention for solving the above-mentioned object is an internal combustion engine comprising a piston that reciprocates in a cylinder liner, wherein at least the thrust side of the outer peripheral surface of the skirt portion of the piston and the opposite side are the inner wall of the cylinder liner. A plurality of grooves extending in the reciprocating direction of the piston are provided so as not to be in direct contact, and a plurality of spheres that are in rolling contact with the inner wall of the cylinder liner are arranged in the groove in the extending direction of the groove.

  According to this configuration, a plurality of grooves are formed in the skirt portion of the piston, and a simple structure in which a plurality of spheres are arranged in the grooves, the piston and the sphere, and the cylinder liner and the sphere are in rolling contact, Even if thrust force acts, the thrust side of the piston and the opposite side do not directly contact the inner wall of the cylinder liner. Therefore, a large force does not act on the piston ring, and the piston friction can be reduced. Further, since the piston clearance is reduced, the piston slap can be reduced and the slap noise can be reduced.

  In addition, by providing a plurality of spheres in the groove, there are a plurality of contact points, pressure is dispersed, and local pressure concentration on the cylinder liner can be reduced. Furthermore, since the sphere of the present invention is configured to roll not only in the reciprocating direction of the piston but also in all directions such as the circumferential direction of the piston, it rolls even when a force other than the thrust force acts on the piston. Failure can be prevented.

  In the internal combustion engine described above, when at least three or more of the grooves in which the sphere is disposed are arranged in an annular shape along the outer peripheral surface of the skirt portion, a plurality of thrust forces are applied when a thrust force acts on the piston. Since the thrust force is dispersed by a plurality of spheres arranged in the groove, piston friction can be further reduced. Moreover, piston clearances other than the thrust side and the opposite side can be reduced, and piston slap can be further reduced. In particular, since the piston slap is suppressed and the force is dispersed in the explosion process, the piston slap can be reduced and the piston friction can be reduced.

  In addition, in the above internal combustion engine, when an oil supply hole for supplying oil to the sphere arranged in the groove is provided, the engine oil attached to the outer peripheral surface of the piston due to spray oil supply, oil jet, or the like is removed from the oil supply hole. Therefore, the friction between the sphere and the groove and between the sphere and the cylinder liner can be further reduced.

  An internal combustion engine manufacturing method for solving the above problem is the internal combustion engine manufacturing method described above, wherein a groove is formed in the reciprocating direction of the piston on the outer peripheral surface of the piston skirt, and the cylinder When the piston is inserted into the liner, a plurality of spheres are arranged in the groove so as to roll in the reciprocating direction and in all directions.

According to this method, when a groove is formed in the skirt portion of the piston by excavation or casting and installed in the cylinder liner, it is only necessary to arrange a plurality of spheres in the groove, and it can be easily manufactured. . In addition, since the rolling contact with the cylinder liner is a sphere, the machining of the shaft and the like is unnecessary, and the number of machining steps can be reduced.

  A vehicle for solving the above problem is configured by mounting the internal combustion engine described above. According to this configuration, it is possible to improve fuel efficiency by reducing piston friction, and to reduce slap noise by reducing piston slap. Moreover, since the effect can be obtained with a simple structure, the manufacturing cost can be reduced.

  According to the present invention, the piston clearance can be reduced, the piston slap can be reduced, and the piston friction can be reduced with a simple structure.

1 is a side sectional view showing an internal combustion engine according to a first embodiment of the present invention. It is sectional drawing of the side which showed the internal combustion engine of 1st Embodiment which concerns on this invention, and is the figure which showed the arrangement | positioning which arranged the rolling support structure in the reciprocating direction of the piston. It is sectional drawing of the plane which showed the internal combustion engine of 2nd Embodiment which concerns on this invention, (a) shows thrust force, (b) is the figure which showed forces other than thrust force. FIG. 6 is a plan sectional view showing an internal combustion engine according to a second embodiment of the present invention, in which (a) shows a diagram in which four rolling support structures are arranged at equal intervals, and (b) shows six rolling support structures. The figure which has arrange | positioned the dynamic support structure at non-equal intervals is shown. It is sectional drawing of the side surface which showed the internal combustion engine of 3rd Embodiment concerning this invention. 2 is a table showing piston friction of an internal combustion engine, (a) showing a conventional internal combustion engine, and (b) showing an internal combustion engine according to an embodiment of the present invention. It is the table | surface which showed the piston slap of an internal combustion engine, (a) shows the conventional internal combustion engine, (b) is the table | surface which showed the internal combustion engine of embodiment which concerns on this invention. It is the side view which showed the conventional internal combustion engine.

  Hereinafter, an internal combustion engine according to an embodiment of the present invention and a vehicle equipped with the internal combustion engine will be described with reference to the drawings. Here, one cylinder of an in-line four-cylinder diesel engine will be described as an example, but the remaining other cylinders have the same configuration. The present invention is not limited to a diesel engine but can be applied to a gasoline engine, and the number of cylinders and the arrangement of the cylinders are not limited. Note that the dimensions of the drawings are changed so that the configuration can be easily understood, and the ratios of the thicknesses, widths, lengths, and the like of the respective members and parts do not necessarily match the ratios of actually manufactured parts.

  First, an internal combustion engine according to a first embodiment of the present invention will be described with reference to FIG. Here, the surface to which the thrust force of the inner wall of the cylinder liner 2 is applied is the thrust surface 2a, and the opposite side is the anti-thrust surface 2b. The direction in which the thrust force acts, that is, the direction orthogonal to the axis of the piston pin 5 is defined as the x direction, the reciprocating direction of the piston 3 is defined as the y direction, and the axial direction of the piston pin 5 is defined as the z direction.

  The engine (internal combustion engine) 1 includes a piston 3 that reciprocates in a cylinder liner 2. A connecting rod 4 connected to a crankshaft (not shown) is connected to the piston 3 via a piston pin 5. The piston 3 is provided with a top ring 6a, a second ring 6b, and an oil ring 6c (hereinafter collectively referred to as the ring 6).

  In addition, rolling support structures 10a and 10b are provided on the outer peripheral surface of the skirt portion 3a of the piston 3, respectively. The rolling support structure 10a is provided on a surface of the outer peripheral surface of the skirt portion 3a facing the thrust surface 2a and the anti-thrust surface 2b of the cylinder liner 2, and includes a groove 11a and a plurality of steel balls 12a. The rolling support structure 10b has the same configuration.

  The rolling support structure 10a is configured such that a plurality of steel balls 12a are loosely fitted in the groove 11a so as to roll in all directions, and the plurality of steel balls 12a are in rolling contact with the thrust surface 2a. In this embodiment, at least the rolling support structure 10a is provided so as to be in rolling contact with the thrust surface 2a, and the rolling support structure 10b is provided so as to be capable of rolling contact with the anti-thrust surface 2b.

  A plurality of hard spheres 12a are loosely fitted in the groove 11a of the rolling support structure 10a by a method such as excavation or casting, and the opening shape of the groove 11a is longitudinal in the y direction so that the hard spheres 12a can roll in all directions. The cross section of the xz plane is semicircular.

  The length of the groove 11a in the longitudinal direction is a length that allows a plurality of steel balls 12a to be arranged side by side. In this embodiment, the length is from the bottom of the oil ring 6c to the vicinity of the lower surface of the piston 3. This length is not limited as long as a plurality of steel balls 12a can be arranged. However, if many hard balls 12a are arranged in the y direction, piston slap can be further reduced.

  The depth of the groove 11a is a depth at which the hard sphere 12a can be brought into contact with the thrust surface 2a when the hard sphere 12a is disposed in the groove 11a. Preferably, the area protruding from the groove 11a is less than half the surface area of the hard sphere 12a. To be.

  The steel balls 12a of the rolling support structure 10a are formed into a spherical shape by a method such as casting a metal such as iron, an aluminum alloy, or a titanium alloy. Further, the portion protruding from the groove 11 a is configured to contact the inner wall of the cylinder liner 2. The size of the steel ball 12a is preferably as small as possible in contact area with the thrust surface 2a because piston friction is reduced.

  The steel ball 12a is not limited to the above-described configuration as long as it is disposed in the groove 11a and can roll in all directions. For example, the surface of the steel ball 12a may be coated with a fluorine resin to reduce the frictional force.

  According to the above configuration, the steel balls 12a and 12b have a simple structure in which the plurality of steel balls 12a and 12b are disposed in the grooves 11a and 11b, even if the thrust force Tf acts on the piston 3. Is in rolling contact with the thrust surface 2a and the anti-thrust surface 2b of the cylinder liner 2, so that the force applied to the ring 6 and the skirt portion 3a of the piston 2 is reduced, and piston friction can be reduced. Further, since the steel balls 12a and 12b protrude from the grooves 11a and 11b, the piston clearance CL between the thrust surface 2a and the anti-thrust surface 2b and the piston 3 is reduced, so that the piston friction is reduced. And piston slap can be reduced.

  Further, since the plurality of steel balls 12a and 12b are in contact with the thrust surface 2a and the anti-thrust surface 2b, there are a plurality of contact points with the thrust surface 2a and the anti-thrust surface 2b. Since the pressure applied to the anti-thrust surface 2b can be dispersed, it is possible to prevent local concentration of pressure on the thrust surface 2a and the anti-thrust surface 2b. Thereby, seizing and scuffing of the cylinder liner 2 and the piston 3 can be prevented.

The rolling support structure 10a described above only needs to form the steel ball 12a as a sphere, and the plurality of steel balls 12a can be in contact with the surface of the thrust surface 2a of the cylinder liner 2 to roll in all directions. The configuration is not limited to the above. For example, as shown in FIG. 2, two rolling support structures 10aA and 10aB may be provided in the y direction.

  Next, an internal combustion engine according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3A, the engine 30 includes rolling support structures 31 to 38 having the same configuration as the above-described rolling support structure, with pistons 3 on the thrust surface 2a and the anti-thrust surface 2b of the cylinder liner 2. A plurality of pistons 3 are arranged in an annular shape on the outer peripheral surface of the piston 3 so that they do not directly contact each other.

  Since the piston pin 4 is press-fitted into the piston 3 by press fit, and the piston pin 4 is fitted into the piston 3, the grooves of the rolling support structures 31 to 38 are also formed on the end surface of the piston pin 4. Can do. When using a method in which the piston 3 and the piston pin 4 are fitted to each other with a circlip at both ends of the piston pin 4 by a full float, it is preferable to avoid the end face of the piston pin 4 and form a groove. In this embodiment, the eight rolling support structures 31 to 38 are arranged at equal intervals, the rolling support structure 31 is in rolling contact with the thrust surface 2a, and the rolling support structure 35 is in rolling contact with the anti-thrust surface 2b. Arranged.

  According to this configuration, when a thrust force Tf is received and a force acts in the x direction, the force can be dispersed by the roller guide mechanisms 31, 32, and 38. Further, as shown in FIG. 3B, when a z-direction force acts on the piston 3, the force can be dispersed by the roller guide mechanisms 32, 33, and 34.

  As described above, when the rolling support structures 31 to 38 are arranged annularly along the outer peripheral surface of the piston 3, no matter which direction of the piston 3 acts, the force is applied by the plurality of rolling support structures. Since it can disperse | distribute, piston friction can be reduced. Further, since the piston clearance CL is reduced over the entire outer periphery of the piston 3, the piston 3 is not inclined in any direction, so that occurrence of piston slap can be reduced and slap noise can be reduced. Particularly, since the force can be dispersed by suppressing the swing of the piston 3 in the explosion process, the piston slap can be reduced and the piston friction can be reduced.

  In this embodiment, eight positions are arranged so as to form an annular shape on the outer peripheral surface of the piston 3, but the piston 3 is not in direct contact with each of the thrust surface 2a and the anti-thrust surface 2b. The arrangement is not limited to the above as long as it can be arranged so as to exert an effect on the force that is in rolling contact and acts in the z direction that is the axial direction of the piston pin 4.

  For example, as shown in FIG. 4 (a), when the weight of the skirt portion 3a is reduced except for the surface on the thrust surface 2a side and the surface on the anti-thrust surface 2b side, You may arrange | position the four rolling support structures 41-44 on an outer peripheral surface at equal intervals. Further, as shown in FIG. 4B, a large number of the six rolling support structures 51 to 56 may be arranged in a portion where force is concentrated rather than at equal intervals.

  According to this configuration, the rolling support structures 31, 32, and 36 that are in contact with the surface of the thrust surface 2a having the greatest influence of the thrust force are arranged on the thrust surface 2a with a small space therebetween, so that the influence of the thrust force is reduced. It can be further reduced, piston friction can be reduced, and generation of slap noise can be prevented. Moreover, even if the outer peripheral surface of the skirt part 3a is not circular shape, force can be disperse | distributed by arrange | positioning several rolling support structures.

  Next, a third embodiment according to the present invention will be described with reference to FIG. The engine 50 of this embodiment includes a groove 51, a steel ball 52, and an oil supply path 53. The oil supply path 53 is a through-hole penetrating from the outer peripheral surface side of the skirt portion 3 a of the groove 51 toward the inner peripheral surface so as to guide the oil to the steel ball 52 disposed in the groove 51.

  The operation of the engine 50 will be described. When the piston 3 reciprocates, a crankshaft (not shown) scrapes the engine oil OL, or an oil jet (not shown) injects the engine oil OL toward the joint between the piston pin 4 and the connecting rod 5. As a result, the engine oil OL is guided to the joint portion between the piston pin 4 and the connecting rod 5, and the friction is reduced. At this time, the engine oil OL scattered on the inner peripheral surface of the skirt portion 3 a can be supplied to the steel ball 52 via the oil supply path 53.

  According to the above operation, the engine oil OL can be supplied to the steel ball 52 disposed in the groove 51 via the oil supply path 53, so the steel ball 52 and the groove 51, and the steel ball 52 and the thrust surface. Friction with 2a can be reduced.

  The oil supply path 53 is not limited to the above configuration as long as the engine oil OL can be supplied to the steel ball 52 disposed in the groove 51. One oil supply path 53 may not be provided for one steel ball 52, and one oil supply path 53 may be provided for at least one groove 51. Further, the shape of the oil supply path 53 is not particularly limited.

  FIG. 6 shows the magnitude of piston friction with respect to a predetermined crank angle when the above-described engines 1, 20, 30, 40 and 50 are actually operated, and FIG. 7 shows the vibration acceleration with respect to the predetermined crank angle. Show. In order to easily understand the effect, the figure also shows a piston having a conventional configuration.

  Compared to the conventional engine shown in FIG. 6 (a), in the engine of the present invention shown in FIG. 6 (b), the friction of the ring 6 of the piston 3 and the friction of the skirt portion 3a are greatly reduced. I understand that. In particular, the friction of the ring 6 is reduced.

  Further, it can be seen that the vibration acceleration is greatly reduced in the engine of the present invention shown in FIG. 7B compared to the conventional engine shown in FIG. This is a result of the fact that the piston slap is greatly reduced due to the low frequency and low amplitude of the piston of the present invention.

  From the above results, it can be seen that the engine of the present invention can reduce piston friction and piston slap with a simple structure. Therefore, a vehicle equipped with the engine of the present invention can improve fuel efficiency and reduce slap noise, and can prevent cylinder liner and piston burning and scuffing and improve durability. Can do. Furthermore, since the above effects can be realized with a simple structure, the manufacturing cost can also be reduced.

  The internal combustion engine of the present invention has a simple structure, can reduce piston friction, and can reduce piston slap. Therefore, the internal combustion engine of the present invention is used particularly for a vehicle equipped with a diesel engine that has a high in-cylinder pressure and generates a large thrust force. be able to.

1, 20, 30, 40, 50 engine (internal combustion engine)
2 Cylinder liner 2a Thrust surface 2b Anti-thrust surface 3 Piston 4 Connecting rod 5 Piston pin 6 Ring 10a, 10b, 21-28, 31-34, 41-46 Rolling support structure 11a, 11b Groove 12a, 12b Steel ball Tf Thrust force 51 Groove 52 Steel ball 53 Oil supply path

Claims (5)

  In an internal combustion engine having a piston that reciprocates within a cylinder liner, the piston extends in the reciprocating direction so that at least the thrust side and the opposite side of the outer peripheral surface of the skirt portion do not directly contact the inner wall of the cylinder liner. An internal combustion engine characterized in that a plurality of grooves are provided, and a plurality of spherical bodies that are in rolling contact with the inner wall of the cylinder liner are arranged in the grooves in the extending direction of the grooves.   2. The internal combustion engine according to claim 1, wherein at least three or more of the grooves in which the spheres are arranged are arranged in an annular shape along the outer peripheral surface of the skirt portion.   The internal combustion engine according to claim 1, further comprising an oil supply path that supplies oil to the sphere disposed in the groove.   3. The method of manufacturing an internal combustion engine according to claim 1, wherein a groove is formed in a reciprocating direction of the piston on an outer peripheral surface of a piston skirt portion, and the groove is inserted into the cylinder liner when the piston is inserted. A method of manufacturing an internal combustion engine, wherein a plurality of spheres are arranged to roll in the reciprocating direction and in all directions.   A vehicle comprising the internal combustion engine according to claim 1.