CN210003388U - Lower connecting rod and engine with same - Google Patents

Abstract

The utility model discloses an lower connecting rods and have its engine be provided with on this lower connecting rod with bent axle complex centre bore, the lower connecting rod includes upper connecting rod portion, control link portion, upper connecting rod portion with the at least end of control link portion junction links to each other through the hinge pin hinge, be provided with in the upper connecting rod portion and be suitable for the upper connecting rod pinhole of being connected with upper connecting rod rotation, the upper connecting rod pinhole is in following and being on a parallel with the direction of upper connecting rod length forms the projection region, when the engine is in the biggest explosive pressure, the hinge pin is located in the projection region.

Description

Lower connecting rod and engine with same

Technical Field

The utility model relates to an automotive filed particularly, relates to kinds of lower connecting rods and have its engine.

Background

The compression ratio of the engine is the ratio of the volume of the cylinder when the piston moves to the bottom dead center to the volume of the combustion chamber when the piston moves to the top dead center. Most of the existing engines are fixed compression ratio engines, and have low fuel combustion efficiency, poor economical efficiency and high emission. With the development of the variable compression ratio technology, the engine starts to increase a compression ratio adjusting mechanism, changes the volume of a combustion chamber by changing the top dead center position of a piston and the like, thereby changing the compression ratio to meet different engine load requirements and enable the engine to work in an optimal working area all the time, thereby improving the dynamic property, reducing the oil consumption, reducing the emission and well solving the contradiction between the dynamic property and the economical efficiency as well as the emission.

At present, a typical structure for changing the top dead center position of an engine piston is a multi-connecting rod mechanism, a lower connecting rod of the multi-connecting rod mechanism is connected with a connecting rod neck of a crankshaft, but when the engine works, the lower connecting rod is stressed maximally due to inertia force, the structural design requirement is strict, the assembly is complex, in addition, two parts of the lower connecting rod are connected through bolts, and the stress at the bolts is severe.

SUMMERY OF THE UTILITY MODEL

In view of this, the present invention provides lower connecting rods to improve the stress condition of the lower connecting rods.

In order to achieve the above purpose, the technical scheme of the utility model is realized like this:

lower connecting rods, wherein the lower connecting rods are provided with center holes matched with the crankshafts, each lower connecting rod comprises an upper connecting rod part and a control connecting rod part, at least ends of the joints of the upper connecting rod part and the control connecting rod part are hinged and connected through hinge pins, the upper connecting rod part is provided with upper connecting rod pin holes suitable for being rotatably connected with the upper connecting rods, the upper connecting rod pin holes form a projection area along the direction parallel to the length of the upper connecting rods, and the hinge pins are positioned in the projection area when the engine is at the maximum explosive pressure.

According to the utility model discloses a some embodiments, go up connecting rod portion with be formed with the die joint between the control link portion, just it is half a hole to be provided with the center in the last connecting rod portion, be provided with half a hole in center down in the control link portion, go up half a hole in center with half a hole surround down in center and enclose into the centre bore, the plane of die joint place is passed the axis setting of centre bore.

Optionally, the axis of the hinge pin lies in the plane of the parting plane.

According to the embodiments of the utility model, the control connecting rod part is provided with a control connecting rod pin hole, the included angle between the central connecting line of the upper connecting rod pin hole and the control connecting rod pin hole and the parting surface is theta, theta satisfies that theta is more than or equal to 45 degrees and less than or equal to 65 degrees.

According to the utility model discloses an some embodiments, the projection region with the region between the centre bore sets up the strengthening rib.

, an interference area is provided between the projected area and the central bore, and the stiffener is at least partially located within the projected area between the interference area and the upper link pin bore.

Specifically, the interference area occupies the maximum proportion of the central hole by no more than 1%.

According to the utility model discloses an some embodiments, go up connecting rod portion with wherein tie points of control link portion are the spiro union tie point, the spiro union tie point is located outside the projection area.

According to some embodiments of the present invention , the inner surface of the upper central half-hole and the lower central half-hole are provided with a wear resistant coating.

Compared with the prior art, the lower connecting rod of the utility model has the following advantages:

lower connecting rod, when the engine is in the biggest explosive pressure, the hinge pin is located the projection region, can improve the atress of lower connecting rod from this.

Another objects of the present invention are to provide engines, which include a piston adapted to move in a cylinder of the engine, a crankshaft having a main journal rotatably disposed on a cylinder body of the engine, a lower link disposed on the lower journal of the crankshaft, an upper link connected between the piston and the lower link, and a compression ratio adjusting mechanism for adjusting a position of the piston in the cylinder, the compression ratio adjusting mechanism including a control link hinged to the lower link.

Compared with the prior art, the engine has the following advantages:

(1) the engine, the part quantity that compresses ratio adjustment mechanism is less, alright in order to reach the purpose that changes the engine compression ratio, be favorable to reducing the assembly process of engine from this, and part quantity is less, is favorable to improving the operational reliability that compresses ratio adjustment mechanism.

(2) The engine, after adopting above-mentioned lower connecting rod, because the at least tie points of last connecting rod portion and control link portion are the rotation tie point, made things convenient for the assembly of lower connecting rod and bent axle from this.

(3) The engine, when the engine is in the biggest explosive pressure, the hinge pin is located the projection region, can improve the atress of lower connecting rod from this.

Drawings

The accompanying drawings, which form part of the present invention, are provided to provide an understanding of the present invention with respect to step , the exemplary embodiments and descriptions thereof are provided to explain the present invention and not to constitute an undue limitation on the invention, in the accompanying drawings:

FIG. 1 is an assembled schematic view of a piston, an upper connecting rod, a lower connecting rod, a crankshaft, a compression ratio adjustment mechanism;

FIG. 2 is an assembled view of the piston, upper link, lower link, and compression ratio adjustment mechanism;

FIG. 3 is an exploded view of the upper connecting rod, lower connecting rod, crankshaft, control connecting rod, and bearing shell;

FIG. 4 is a schematic view of the assembly of the upper link, lower link, link neck, control link, and bearing shell;

FIG. 5 is a schematic view of the lower bearing shell and the height of the remainder of the lower bearing shell;

FIG. 6 is an assembled view of the upper link, the control link, and the th embodiment of the lower link;

FIG. 7 is an exploded view of the th embodiment of the lower link;

FIG. 8 is a schematic view of the connection of the hinge socket, the connecting arm and the hinge pin;

FIG. 9 is a force analysis diagram of the upper link, the control link, and the th embodiment of the lower link;

FIG. 10 is a schematic view of a force analysis of the upper link portion and the control link portion using a link bolt connection at both ends;

FIG. 11 is an assembled view of the upper link, the control link, and the lower link of the second embodiment;

FIG. 12 is an exploded schematic view of a lower link of a third embodiment;

FIG. 13 is an assembled view of the lower link of the fourth embodiment;

FIG. 14 is an exploded schematic view of a lower link of the fourth embodiment;

FIG. 15 is an exploded schematic view of a lower link of the fifth embodiment;

FIG. 16 is a cross-sectional view of the upper link portion pivotally connected to the control link portion at the end and the other end connected using a link bolt;

FIG. 17 is a schematic view of a projected area of a lower link of the th embodiment;

FIG. 18 is a schematic illustration of the projected area interfering with the central aperture;

FIG. 19 is an exploded view of the upper link portion and the control link portion of the th embodiment lower link;

FIG. 20 is an exploded view of the upper link portion and the control link portion of the lower link of the fifth embodiment;

FIG. 21 is a schematic view of the relative rotational angles of the upper link portion and the control link portion;

FIG. 22 is a top view of the boss disposed on the upper link portion;

FIG. 23 is an enlarged partial schematic view at M of FIG. 22;

FIG. 24 is a perspective view of the boss provided on the upper link portion;

FIG. 25 is a schematic view of the boss being located on the control link portion with the lower bearing shell having a clearance height;

FIG. 26 is an enlarged partial schematic view at N of FIG. 25;

FIG. 27 is a schematic view of the assembly of the lower connecting rod with the upper and lower bearing shells;

fig. 28 is an exploded view of the lower link and the upper and lower bearing shells.

Description of reference numerals:

the piston 1, the upper connecting rod 2, the crankshaft 4, the main journal 41, the connecting journal 42, the compression ratio adjustment mechanism 7, the control connecting rod 5, the eccentric shaft 6, the drive shaft 61, the eccentric wheel 62, the piston pin a, the connecting pin B, the bush C, the control connecting pin D, the lower connecting rod 3, the upper connecting rod part 31, the upper connecting pin hole 311, the -th threaded hole 314, the upper center half hole 316, the control connecting rod part 32, the control connecting pin hole 321, the second bolt hole 323, the second threaded hole 324, the lower center half hole 326, the center hole 33, the connecting rod bolt 35, the boss 37, the hinge hole seat boss 371, the connecting arm boss 372, the reinforcing rib 38, the parting surface 40, the upper segment bush 401, the lower segment parting surface 402, the hinge hole seat 51, the -th hinge seat 511, the second hinge hole seat 512, the connecting arm 52, the -th connecting arm 521, the second connecting arm 522, the hinge pin 53, the hinge pin hole 54, the upper bearing shoe 81.

Detailed Description

It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail with reference to fig. 1 to 28 in conjunction with the embodiments.

Referring to fig. 1-3, an engine may include: the piston 1, the upper connecting rod 2, the lower connecting rod 3, the crankshaft 4 and the compression ratio adjusting mechanism 7.

Specifically, the lower connecting rod 3 of the embodiment of the present invention is adapted to be hingedly connected to a crankshaft 4 of an engine, and the piston 1 is movable in a cylinder of the engine, as shown in fig. 1 to 2, and the piston 1 is movable in a cylinder bore of the cylinder in an up-down direction of fig. 1 to 2.

The main journal 41 of the crankshaft 4 is rotatably provided in the cylinder block of the engine, and the connecting journal 42 of the crankshaft 4 is offset from the central axis of the main journal 41. There may be a plurality of connecting journals 42 of the crankshaft 4.

The lower link 3 is sleeved on connecting journals 42, specifically, the lower link 3 is provided with a central hole 33, the connecting journals 42 are located in the central hole 33, the lower link 3 and the connecting journals 42 can rotate mutually, in embodiments, a connecting journal pin or a bearing bush C can be arranged between the lower link 3 and the connecting journals 42 to reduce the abrasion of the lower link 3 and the connecting journals 42 and prolong the service life of parts of the engine.

The upper connecting rod 2 is connected between the piston 1 and the lower connecting rod 3, that is, the th end of the upper connecting rod 2 is connected with the piston 1, and the second end of the upper connecting rod 2 is connected with the lower connecting rod 3. specifically, the th end of the upper connecting rod 2 is hinged with the piston 1, and the second end of the upper connecting rod 2 is hinged with the lower connecting rod 3, so that the upper connecting rod 2 and the piston 1 can rotate with each other, and the upper connecting rod 2 and the lower connecting rod 3 can rotate with each other, so that when the lower connecting rod 3 rotates around the connecting rod neck 42 sleeved with the lower connecting rod 3, the upper connecting rod 2 can be driven to move, and the piston 1 can be driven to move up.

As shown in the figures 1-2, the compression ratio adjusting mechanism 7 can comprise an eccentric shaft 6 and a control connecting rod 5, wherein the control connecting rod 5 is connected between the lower connecting rod 3 and the eccentric shaft 6, the th end of the control connecting rod 5 is connected with the lower connecting rod 3, and the second end of the control connecting rod 5 is eccentrically connected with the eccentric shaft 6, so that when the eccentric shaft 6 rotates, the power of the eccentric shaft 6 can be transmitted to the lower connecting rod 3 through the control connecting rod 5 to enable the lower connecting rod 3 to rotate around the sleeved connecting rod neck 42.

Specifically, when the eccentric shaft 6 rotates, the control connecting rod 5 is pushed to rotate, the control connecting rod 5 pushes the lower connecting rod 3 to rotate, the lower connecting rod 3 pushes the upper connecting rod 2 to rotate, and the upper connecting rod 2 pushes the piston 1 to move up and down, so that the position of the piston 1 in the cylinder can be adjusted. The piston 1 moves up and down, changing the volume of the combustion chamber and thus the compression ratio. That is, the compression ratio adjustment mechanism 7 may function to change the engine compression ratio. By changing the compression ratio, the requirements of different loads of the engine can be met, and the engine can always work in the optimal working area, so that the dynamic property is improved, the oil consumption is reduced, the emission is reduced, the contradiction between the dynamic property and the economical efficiency and the emission is well solved, and the engine can always work in the optimal oil consumption area.

It should be noted that, in the description of the present invention, " th end" of the component refers to the upper end of the drawing, "second end" refers to the lower end of the drawing, but the words indicating the orientation such as " th end", "second end", "upper", "lower", etc. are only for convenience of description and should not be construed as limiting the present invention.

In the specific embodiment, the compression ratio adjusting mechanism 7 has fewer parts, so that the purpose of changing the compression ratio of the engine can be achieved, the assembly process of the engine is favorably reduced, and the working reliability of the compression ratio adjusting mechanism 7 is favorably improved due to the fewer parts.

Referring to fig. 1, the eccentric shaft 6 may include a driving shaft 61 and an eccentric 62, the driving shaft 61 may be rotatably provided on the cylinder block, the eccentric 62 may be eccentrically fitted over the driving shaft 61, and the eccentric 62 may be fixed with respect to the driving shaft 61, an th end of the control link 5 may be hinged to the lower link 3, and a second end of the control link 5 may be hinged to the driving shaft 61 through the eccentric 62, thereby allowing the control link 5 and the lower link 3 to be rotatable with each other and the control link 5 and the driving shaft 61 to be rotatable with each other.

, the compression ratio adjustment mechanism 7 may further include a drive device coupled to the drive shaft 61 and configured to drive the drive shaft 61 in rotation, and more specifically, the drive device provides a drive torque to the drive shaft 61 to rotate the drive shaft 61.

The th end of the upper connecting rod 2 is hinged with the piston 1 through a piston pin A, and the second end of the upper connecting rod 2 is hinged with the lower connecting rod 3 through a connecting rod pin B.

Referring to fig. 1 to 3, , the end of the control link 5 is hinged to the lower link 3 by a control link pin D, and the link pin B and the control link pin D are disposed at both sides of the link neck 42 where the lower link 3 is sleeved, in other words, the lower link 3 is provided with an upper link pin hole 311 and a control link pin hole 321, the upper link pin hole 311 and the control link pin hole 321 are disposed at both sides of the central hole 33 of the lower link 3, preferably, a line connecting the center lines of the upper link pin hole 311 and the control link pin hole 321 passes through the center line of the central hole 33, the link pin B is disposed in the upper link pin hole 311, and the control link pin D is disposed in the control link pin hole 321.

The crankshaft 4 is disposed between the piston 1 and the eccentric shaft 6, thereby bringing the crankshaft 4 closer to the piston 1 so that kinetic energy of the piston 1 can be rapidly transferred to the crankshaft 4 upon combustion of fuel, reducing loss of kinetic energy.

The lower link 3 of the present invention will be described in detail with reference to fig. 1 to 28 in conjunction with the embodiment.

Referring to fig. 2-4, 6-9, 11-21, and 27-28, the lower link 3 according to an embodiment of the present invention may include an upper link portion 31, a control link portion 32, wherein the upper link portion 31 is connected to the control link portion 32, and at least connection points are rotation connection points, and the upper link portion 31 and the control link portion 32 can rotate relative to each other around the rotation connection points, so that the upper link portion 31 and the control link portion 32 can be rotatably mounted on the connecting neck 42 of the crankshaft 4, that is, the lower link 3 can be assembled with the crankshaft 4 by rotating around the rotation connection points.

Compare in traditional mode of using a plurality of bolts alone to connect upper connecting rod portion 31 and control connecting rod portion 32, the utility model provides a rotatory mounting means can guarantee that upper connecting rod portion 31 and control connecting rod portion 32's at least end is assembled in advance at the rotation connecting point department, then changes the angle that opens of upper connecting rod portion 31 and control connecting rod portion 32, makes upper connecting rod portion 31 and control connecting rod portion 32 cooperate with connecting rod neck 42 again, can simplify the assembling process of lower connecting rod 3 and bent axle 4, reduces the assembly degree of difficulty.

The rotation axis of the rotation connection point is parallel to the axis of the central hole 33, so that the rotation track of the upper link part 31 and the rotation track of the control link part 32 are in the same plane , and when the ends of the upper link part 31 and the control link part 32 rotate relatively at the rotation connection point, the opening angle of the other ends of the upper link part 31 and the control link part 32 can be changed.

According to the utility model discloses lower connecting rod 3, upper connecting rod portion 31 and control link portion 32 can revolute the rotation connecting point and take place relative rotation to the assembling process of lower connecting rod 3 and bent axle 4 has been simplified, the assembly degree of difficulty has been reduced.

Referring to fig. 2 to 4, 6 to 9, 11 to 18, and 27 to 28, at the rotational connection point, the upper link portion 31 and the control link portion 32 are rotationally connected by a hinge pin 53. In other words, the hinge pin 53 passes through the upper link portion 31 and the control link portion 32 to achieve the hinge connection of the upper link portion 31 and the control link portion 32. That is, the hinge pin 53 is at the pivot connection point.

referring to FIGS. 2-4, 6-7, 9, 11-21 and 27-28, of the upper link part 31 and the control link part 32 are provided with a hinge socket 51, are provided with a connecting arm 52, hinge sockets 51 and connecting arms 52 are provided with hinge pin holes 54 for mounting hinge pins 53, and hinge pins 53 pass through hinge pin holes 54 of the hinge sockets 51 and hinge pin holes 54 of the connecting arm 52, so as to realize the hinge connection of the upper link part 31 and the control link part 32 at the hinge pins 53, the hinge sockets 51 and the connecting arm 52 form a hinge structure, and the hinge structure forms the above-mentioned rotation connection point.

For example, in the embodiment shown in fig. 11-12, 15, 20-21, the upper link portion 31 is provided with a socket 51 and the control link portion 32 is provided with a connecting arm 52. In the embodiment shown in fig. 2-4, 6-7, 9, 13-14, 16-19, 27-28, the control link part 32 is provided with a hinge socket 51 and the upper link part 31 is provided with a connecting arm 52.

Alternatively, referring to fig. 7-8, 12-15, and 19-20, the connecting arm 52 includes th connecting arm 521 and second connecting arm 522, and the th connecting arm 521 and second connecting arm 522 are spaced apart along the axial direction of the hinge pin 53, the hinge base 51 is sandwiched between the th connecting arm 521 and second connecting arm 522, and the hinge pin 53 sequentially passes through the th connecting arm 521, the hinge base 51 and second connecting arm 522. in other words, the connecting arm 52 is a bifurcated structure and supports both ends of the hinge base 51. the hinge base 51 is a convex structure, and the hinge base 51 is located inside the connecting arm 52 after assembly and supports the middle portion of the hinge pin 53. the hinge pin 53 connects the upper link portion 31 and the control link portion 32 of the lower link 3 to each other at through the hinge pin hole 54 of the hinge base 51 and the connecting arm 52, and at the same time, the upper link portion 31 and the control link portion 32 can relatively rotate around the hinge pin 53 to change the opening angle of the upper link portion 31 and the control link portion 32.

Alternatively, in the embodiment shown in fig. 7-8, 12, 19, the reaming base 51 is a single reaming base 51.

Alternatively, in the embodiment shown in fig. 13-15 and 20, the hinge socket 51 includes th hinge socket 511 and the second hinge socket 512, and the th hinge socket 511 and the second hinge socket 512 are spaced apart along the axial direction of the hinge pin 53, so that the thickness of the hinge socket 51 can be reduced, and the material of the hinge socket 51 can be saved, the th hinge socket 511 and the second hinge socket 512 are both provided with hinge pin holes 54, when the hinge socket 51 is sandwiched between the th connecting arm 521 and the second connecting arm 522, the th hinge socket 511 is abutted with the th connecting arm 521, the second hinge socket 512 is abutted with the second connecting arm, and the hinge pin 53 sequentially passes through the th connecting arm 521, the th hinge socket 511, the second hinge socket 512 and the hinge pin hole 54 on the second connecting arm 522, so as to connect the upper connecting rod portion 31 and the control connecting rod portion 32 to the .

In the embodiments of the present invention, referring to fig. 6, 9, and 17, a parting surface 40 is formed between the upper link part 31 and the control link part 32, the lower link 3 is divided into two parts at the parting surface 40, and the surfaces of the upper link part 31 facing the control link part 32 and the surfaces of the control link part 32 facing the upper link part 31 are both the parting surface 40.

Referring to fig. 7, 12, 14-15, and 19-20, the upper connecting rod portion 31 is provided with an upper central half-hole 316, the control connecting rod portion 32 is provided with a lower central half-hole 326, the upper central half-hole 316 and the lower central half-hole 326 surround a central hole 33, the central hole 33 is adapted to be sleeved on the connecting rod neck 42 of the crankshaft 4, and the crankshaft 4 drives the lower connecting rod 3 to move when rotating.

The plane of parting plane 40 is disposed through the axis of central bore 33, thereby facilitating weight balance between upper link portion 31 and control link portion 32, facilitating dynamic balance performance of lower link 3, and facilitating simplification of the machining process of upper link portion 31 and control link portion 32.

The hinge hole seat 51 mainly functions to connect the upper link part 31 and the control link part 32 and to support the hinge pin 53, and may be provided on any side of the parting surface 40 of the lower link 3, and the hinge hole seat 51 may be provided on the other side of the parting surface 40 of the lower link 3.

The hinge hole seat 51 has two main structures on the side of the parting surface 40 of the lower connecting rod 3, namely, a structure , in which the hinge hole seat 51 and the upper connecting rod pin hole 311 are both located on the upper connecting rod portion 31, as shown in fig. 11-12, 15, 20-21, the upper connecting rod portion 31 is a bifurcated structure, supports both ends of the connecting rod pin B, and the upper connecting rod portion 31 and the hinge hole seat 51 form a Y-shaped structure, wherein the hinge hole seat 51 is a Y-shaped bottom, and the upper connecting rod portion 31 is a Y-shaped top, which is a structure in which stress is easily concentrated at the joint between the hinge hole seat 51 and the upper connecting rod portion 31 when a force is applied, and the joint transition between the two is a large arc, and in the embodiment of fig. 11 and 21, in order to avoid the movement locus of the upper connecting rod 2 to which the pin hole 311 is connected, the hinge hole seat 51 and the upper connecting rod portion 31 are provided with an escape groove, and in the second structure, the hinge hole seat 51 and the control connecting rod pin hole seat hole 321 are both located on the control connecting rod portion 32, as shown in fig. 2-4, 6-7, 9, 13-14, 13-19, and , and the hinge hole seat is not necessary to make the escape groove structure, and the escape structure is slightly better than the hinge seat 51, and the hinge hole structure.

, referring to fig. 9 and 11, the axis of the hinge pin hole 54 is located in the plane of the parting plane 40, i.e. the axis of the hinge pin 53 is located in the plane of the parting plane 40, i.e. the plane of the parting plane 40 passes through the center of the hinge pin 53, thereby avoiding the lower connecting rod 3 from interfering with the crankshaft 4 during the assembly process and ensuring the assembly work to be carried out smoothly.

Alternatively, the axis of the hinge pin hole 54 is parallel to the axis of the central hole 33, and when the upper link portion 31 and the control link portion 32 rotate relatively, the rotation center line is the axis of the hinge pin hole 54, thereby ensuring that the rotation locus of the upper link portion 31 and the rotation locus of the control link portion 32 are in the same plane.

In the embodiments of the present invention, referring to fig. 7, 12-16, 19-21, and 27-28, the upper link portion 31 is provided with an upper link pin hole 311, the control link portion 32 is provided with a control link pin hole 321, and as shown in fig. 11, when viewed from the axial direction of the lower link 3, the parting plane 40 includes an upper parting plane 401 near the upper link pin hole 311 and a lower parting plane 402 near the control link pin hole 321, and the hinge pin 53 is located at the upper parting plane 401.

In embodiments of the present invention, referring to fig. 3-4, 7, and 12-16, of the connection points of the upper link portion 31 and the control link portion 32 are bolt connection points.

referring to fig. 3-4, 7, 13-14 and 16, the upper link part 31 is provided with an upper link pin hole 311, the control link part 32 is provided with a control link pin hole 321, a central hole 33 is defined between the upper link part 31 and the control link part 32, the rotation connection point is located at the side of the central hole 33 near the upper link pin hole 311, and the bolt connection point is located at the side of the central hole 33 near the control link pin hole 321.

If the distance between the center line of the hinge pin 53 and the center line of the center hole 33 is small, the wall thickness of the center hole 33 near the hinge pin 53 is reduced, and when a force is applied, the deformation generated in the reduced area is large, so that the failure risk of the lower connecting rod 3 is increased. On the other hand, if the distance between the center line of the hinge pin 53 and the center line of the center hole 33 is increased, the entire structure of the lower link 3 becomes large, which is disadvantageous to the entire assembly of the lower link 3. Therefore, the distance between the center line of the hinge pin 53 and the center line of the center hole 33 is preferably in the range of 39mm to 45 mm.

Alternatively, the connecting bolt 35 is provided at the screw-coupling point, and when the lower connecting rod 3 is assembled with the neck 42 of the crankshaft 4, the upper connecting rod part 31 is hinge-coupled with the end of the control connecting rod part 32 using the hinge pin 53, then at least of the upper connecting rod part 31 and the control connecting rod part 32 are rotated to increase the opening angle of the upper connecting rod part 31 and the control connecting rod part 32, thereby facilitating the arrangement of the upper connecting rod part 31 and the control connecting rod part 32 on the neck 42 of the crankshaft 4, and then the upper connecting rod part 31 and the control connecting rod part 32 are rotated in the opposite direction to bring the upper connecting rod part 31 into contact with the other end of the control connecting rod part 32 and are fixed at the contact position using the connecting bolt 35, thereby completing the assembly of the lower connecting rod 3 with the crankshaft 4.

Alternatively, the central axis of the link bolt 35 is perpendicular to the central axis of the hinge pin 53, thereby facilitating the tightening or loosening operation of the link bolt 35.

Referring to fig. 12 and 15, the control link portion 32 is provided with a second bolt hole 323, the upper link portion 31 is provided with a -th threaded hole 314 (not shown in fig. 15), and the link bolt 35 is threaded through the second bolt hole 323 and then screwed into the -th threaded hole 314, so as to realize the screwing of the upper link portion 31 and the control link portion 32 at the screwing connection point.

Referring to fig. 3 and 14, a second threaded hole 324 is formed in the control link portion 32, an th bolt hole (not shown in fig. 3 and 14) is formed in the upper link portion 31, and the link bolt 35 is inserted through the th bolt hole and then screwed into the second threaded hole 324, so that the upper link portion 31 and the control link portion 32 are screwed at the screwing connection point.

The force applied to the lower link 3 will be described with reference to fig. 9 to 10.

In fig. 9-10 and 17, Fa ' are the forces of control link 5 on lower link 3, Fb ' are the resultant forces exerted on lower link 3, Fc ' are the forces of upper link 2 on lower link 3, Fx ' are the shear forces, Fy ' are the pressing forces. When the engine is operated, the explosion pressure of the cylinder is transmitted to the upper connecting rod 2 through the piston 1, and the upper connecting rod 2 transmits a force Fc to the lower connecting rod 3. Fc generates a component force, which is a shearing force Fx, at the parting surface 40 of the lower link 3.

Fig. 10 is a force analysis diagram of the upper link portion 31 and the control link portion 32 connected at both ends by the link bolt 35, Fx' acts on the link bolt 35, and the shear resistance of the link bolt 35 is weak, so that the left link bolt 35 shown in fig. 10 is easily damaged. In the structure of the lower link 3 shown in fig. 10, in order to reduce the shearing force Fx ' applied to the link bolt 35, it is necessary to ensure that the direction of the force Fc ' transmitted from the upper link 2 to the lower link 3 is substantially perpendicular to the parting plane 40 of the lower link 3 at a time near the maximum explosive pressure of the engine, and at this time, the range of the included angle θ ' between the parting plane 40 and the connecting line between the upper link pin hole 311 and the control link pin hole 321 is small, which is not beneficial to the adjustment of the structure and size of the lower link 3.

Fig. 9 is a schematic view of the force analysis of the connection of the upper link part 31 and the control link part 32 using the hinge pin 53 and the other end using the link bolt 35, wherein the lower link 3 is subjected to a force that causes the control link part 32 to be tensioned and the upper link part 31 to be compressed at the time of maximum explosive pressure of the engine, and the lower link 3 is subjected to a force that causes the control link part 32 to be compressed and the upper link part 31 to be tensioned at the time of maximum inertial force, because the maximum explosive pressure is much greater than the maximum inertial force, the hinge pin 53 is subjected to a force closer to the upper link pin hole 311 than the hinge pin 53 is subjected to a force closer to the control link pin hole 321, and therefore the hinge pin 53 is preferentially designed to a position closer to the upper link pin hole 311, as shown in fig. 2-4, 6-7, 9, 11, 13-14, 16-19, 21, 27-28, since the lower link 3 employs the hinge pin 53, and the shear force Fx acts on the hinge pin 51 and the link pin 52, and finally the hinge pin 53 is overcome the shear resistance of the hinge pin, thereby significantly improving the shear resistance of the hinge pin 35.

In addition, the explosion pressure of the cylinder is transmitted to the force Fc of the lower link 3, so that the upper link portion 31 of the lower link 3 is pressed, and if the connection is performed by the link bolt 35, when the pressing force Fy acts on the link bolt 35, the end of the threaded hole is likely to have stress concentration, resulting in thread failure. And by adopting the hinge structure, the pressing force Fy acts on the hinge pin 53 through the connecting arm 52, and the hinge pin hole 54 on the connecting arm 52 disperses the pressing force Fy along the edge of the hole, so that the hinge pin 53 is stressed uniformly, and the phenomenon of stress concentration caused by connection of the connecting rod bolt 35 is avoided.

In fig. 9, the hinge pin 53 can bear a large shearing force, and at a time near the maximum explosive pressure of the engine, the direction of the force Fc transmitted from the upper link 2 to the lower link 3 may not be nearly perpendicular to the parting plane 40 of the lower link 3, and the range of the included angle θ between the parting plane 40 and the connecting line between the upper link pin hole 311 and the control link pin hole 321 is larger than the range of the included angle θ' when the link bolts 35 at both ends are connected, and at this time, the included angle θ is between 45 ° and 65 °.

In addition, because the hinge pin 53 cannot exert pretightening force on the lower connecting rod 3, a connection mode capable of exerting pretightening force is required to be adopted at the other end of the lower connecting rod 3, and the connection mode of the upper connecting rod part 31 and the connecting rod bolt 35 at the other end of the control connecting rod part 32 is a connection mode capable of exerting pretightening force.

That is, after the ends of the upper link portion 31 and the control link portion 32 are hinged, the stress on the link bolt 35 at the other end is improved, so that the specification of the link bolt 35 can be properly reduced to save the cost.

Alternatively, in the embodiment shown in fig. 12, 15, 20, the hinge pin 53 may be designed in a position close to the control link pin hole 321.

In order to reduce the axial deformation of the lower connecting rod 3, of the hinge pin holes 54 on the connecting arm 52 and the hinge pin holes 54 on the hinge hole seat 51 are in interference fit when being matched with the hinge pin 53, since the upper connecting rod part 31 and the control connecting rod part 32 of the lower connecting rod 3 can rotate around the hinge pin 53, the other of the hinge pin holes 54 on the connecting arm 52 and the hinge pin holes 54 on the hinge hole seat 51 can be in transition fit or clearance fit, for example, in embodiments of the present invention, referring to fig. 8, the hinge pin 53 is in interference fit with the hinge pin holes 54 of the hinge hole seat 51, the hinge pin 53 is in transition fit or clearance fit with the hinge pin holes 54 of the connecting arm 52, however, in order to reduce the risk of separation of the lower connecting rod 3 due to the clearance between the hinge pin 53 and the hinge pin holes 54 during operation, the transition fit is recommended, in order to further , the clearance between the hinge pin 53 and the hinge pin holes 54 is eliminated, after the lower connecting rod 3 is assembled with the crankshaft 4, pressing force is applied to both sides of the hinge pin holes 53, the hinge pin holes 53 are in radial direction, and the hinge pin holes 53 are in the hinge pin hole 54, and the hinge pin hole 53 is in the hinge pin hole.

In the embodiments not shown in the present invention, the upper connecting rod portion 31 and the control connecting rod portion 32 are connected by two connecting points, and both the two connecting points are rotational connecting points when the upper connecting rod portion 31 and the control connecting rod portion 32 are assembled, the upper connecting rod portion 31 and the control connecting rod portion 32 are hinged at rotational connecting points, the opening angle of the upper connecting rod portion 31 and the control connecting rod portion 32 is adjusted, the upper connecting rod portion 31 and the control connecting rod portion 32 are installed on the crankshaft 4, and the upper connecting rod portion 31 and the control connecting rod portion 32 are fixed at rotational connecting points, so as to install the lower connecting rod 3 on the crankshaft 4.

Referring to fig. 17 to 18, the lower link 3 according to the present invention may include an upper link part 31, a control link part 32, at least end of the connection between the upper link part 31 and the control link part 32 being hingedly connected by a hinge pin 53, the upper link part 31 being provided with an upper link pin hole 311 adapted to be rotatably connected to the upper link 2, the upper link pin hole 311 forming a projected area Q in a direction parallel to the length of the upper link 2, the hinge pin 53 being located within the projected area Q when the engine is under a maximum explosion pressure, the direction parallel to the length of the upper link 2, i.e., the extending direction of the connection line of the piston pin a axis and the link pin B axis, in other words, the upper link pin hole 311 forming the projected area Q in the extending direction of the connection line of the piston pin a axis and the link pin B axis.

Fig. 17 is a schematic diagram of the force applied to the lower link 3 when the engine is in the vicinity of the maximum explosive pressure, and more specifically, when the hinge pin 53 is in the projection region Q, the engine is operated to the vicinity of the maximum explosive pressure, Fc is the force acting on the lower link 3 from the upper link 2 in the direction of the arrow in fig. 17, and the force Fc is divided in the direction of the parting plane 40 of the lower link 3, and the two components are that the shearing force Fx in the direction of the parting plane 40 and the pressing force Fy. Fy perpendicular to the parting plane press the upper link portion 31 of the lower link 3, and the force Fc is in the vicinity of the maximum explosive pressure, so that the component Fy is also large, and the risk of separation of the bearing bush C due to the clearance between the hinge pin 53 and the hinge pin hole 54 is effectively reduced, i.e., β is approximately equal to 90 ° so that the shearing force Fx is small, and the shearing force Fx is mainly borne by the hinge pin 53, so that the connecting rod 35 is substantially free of the connecting rod 35, and the requirement for the bolt 35 is reduced.

According to the utility model discloses lower connecting rod 3, when the engine is in the biggest explosive pressure, hinge pin 53 is located the projection area Q, can improve lower connecting rod 3's atress from this.

In the embodiments of the present invention, as shown in fig. 7 and 17, the control link part 32 is provided with a control link pin hole 321, an included angle between the central connecting line of the upper link pin hole 311 and the control link pin hole 321 and the parting surface 40 is θ, and θ satisfies that θ is greater than or equal to 45 ° and less than or equal to 65 °.

In the embodiments of the present invention, as shown in fig. 17-18, the area between the projection area Q and the central hole 33 is provided with a reinforcing rib 38 to increase the strength and rigidity of the area.

, as shown in FIG. 18, there is an interference area between the projected area Q and the central bore 33, and the stiffener 38 is at least partially located within the projected area Q between the interference area and the upper link pin bore 311.

Specifically, the maximum ratio of the interference area to the central hole 33 is not more than 1% so as to avoid the influence of the overlarge interference area on the bearing performance of the lower connecting rod 3.

Specifically, as shown in fig. 17, a force transmitted from the upper link 2 acts on the lower link 3 through the upper link pin hole 311 in the direction of the arrow, and this force causes deformation in the vicinity of the upper link pin hole 311, so that the distance between the upper link pin hole 311 and the center hole 33 can be shortened to increase the overall rigidity in the vicinity of the upper link pin hole 311. Since the distance between the upper link pin hole 311 and the center hole 33 is shortened, the overall size of the lower link 3 is reduced, making the engine mechanism more compact. Meanwhile, the weight of the lower connecting rod 3 is reduced, the lower connecting rod 3 is lighter, and the inertia force borne by the lower connecting rod is reduced.

The distance between the upper link pin hole 311 and the center hole 33 is shortened so that, in the vicinity of the highest compression ratio of the engine, a projected area Q of the link pin B projected along a straight line passing through the centers of the piston pin a and the link pin B during operation of the mechanism slightly interferes with the center hole 33, that is, an interference area exists between the projected area Q and the center hole 33, and the area of the maximum interference area of the projected area Q and the center hole 33 is about 0.4% of the area of the center hole 33. In the vicinity of the highest compression ratio range, the working condition of the engine is low load, and because the maximum explosion pressure of the low-load working condition is much lower than that of the high-load working condition, under the working condition, the slight interference between the projection region Q and the central hole 33 region has a stress deformation influence on the central hole 33, and the problem can be solved by improving the structural strength of the lower connecting rod 3 in the interference region. The structural rigidity can be enhanced by adjusting the positions of the reinforcing ribs 38 so that the positions of the reinforcing ribs 38 are included in the projection area Q, and the enhancement of the structural rigidity can eliminate the negative influence caused by the deformation under force.

In the embodiments of the present invention, of the upper link portion 31 and the control link portion 32 are bolted joints that are outside the projected area Q. for example, in fig. 17, the hinge pin 53 is located on the left side of the central bore 33 and the bolted joints are located on the right side of the central bore 33.

The utility model discloses an some embodiments, the internal surface of going up central half hole 316 and lower central half hole 326 is provided with wear-resistant coating, can promote the wear resistance of going up central half hole 316 and lower central half hole 326 internal surface from this, like this, when connecting rod 3 and the connecting rod neck 42 of bent axle 4 assemble down, can cancel axle bush C's setting, make wear-resistant coating replace axle bush C to reduce part quantity, simplify assembly process.

Referring to fig. 19 to 21, the lower link 3 according to the present invention may include an upper link portion 31, a control link portion 32, and at least end of the connection between the upper link portion 31 and the control link portion 32 is rotatably connected so that the upper link portion 31 and the control link portion 32 can relatively rotate around the rotation connection point.

Referring to fig. 21, the angle range of the relative rotation between the upper link part 31 and the control link part 32 is α, which is 0 to 170 °, for example, the opening angle α of the upper link part 31 and the control link part 32 around the hinge pin 53 can reach 160 to 170 °, and the lower link 3 can be conveniently put into the cylinder hole during assembly by adjusting the opening angle between the upper link part 31 and the control link part 32.

In the embodiments of the present invention, of the upper link portion 31 and the control link portion 32 are provided with the hinge socket 51, and are provided with the connecting arm 52, and the hinge socket 51 and the connecting arm 52 are rotatably connected.

, the hinge sockets 51 are at least and the connecting arms 52 are at least .

For example, in some embodiments not shown, the hinge eyes 51 and the connecting arms 52 are each , and the hinge eyes 51 and the connecting arms 52 are disposed adjacent to each other.

In the embodiments of the present invention, the thickness of the upper link 31 is equal to that of the control link 32, and the sum of the thicknesses of the reaming base 51 and the connecting arm 52 is equal to that of the upper link 31 or the control link 32, thereby facilitating the balance of the weights of the two parts of the lower link 3.

, the upper link part 31 is provided with an upper link pin hole 311, the control link part 32 is provided with a control link pin hole 321, and in the embodiment of fig. 11 and 21, the hinge hole seat 51 is also located close to the upper link pin hole 311, so that an avoiding groove is provided on the hinge hole seat 51, and the avoiding groove is recessed in a direction away from the upper link pin hole 311 to avoid the movement track of the upper link 2 connected to the upper link pin hole 311.

, referring to fig. 9 and 11, the center of the rotation joint is located in the plane of the parting plane 40, that is, the plane of the parting plane 40 passes through the center of the rotation joint, thereby preventing the lower connecting rod 3 from interfering with the crankshaft 4 during the assembly process.

Referring to fig. 3-4, 7, 12-16, the lower link 3 according to the present invention may include an upper link portion 31, a control link portion 32, wherein the upper link portion 31 is connected to the control link portion 32, and connection points are rotation connection points, and another connection points are adjustable connection points.

Referring to fig. 22 to 28, a parting surface 40 is formed between the upper link part 31 and the control link part 32, and a boss 37 is provided at the parting surface 40 at an end where the upper link part 31 is rotatably connected to the control link part 32.

At the rotational connection point, the hinge pin 53 passes through the hinge pin hole 54 of the upper link portion 31 and the control link portion 32, thereby achieving rotational connection of the upper link portion 31 and the control link portion 32. Due to the clearance between the hinge pin hole 54 and the hinge pin 53, the risk of the bearing shell C separating during operation of the engine is increased. The risk of separation of the bearing shells C can be reduced by providing a boss 37 at the parting plane 40 at the point of the rotary joint and applying an adjusting force at the point of the adjustable joint. Specifically, due to the lever principle, when a small adjusting force is applied to the adjustable connecting point, the boss 37 can generate large deformation, so that the lower connecting rod 3 can apply large pretightening force to the bearing bush C, and the risk of separation of the bearing bush C is reduced. Meanwhile, the pretightening force can also prevent the deformation of the central hole 33 of the lower connecting rod 3 caused by the elastic tension of the bearing bush C.

According to the utility model discloses a lower connecting rod 3 sets up boss 37 through the die joint 40 department at the rotation junction to exert the regulating force in adjustable junction, can make boss 37 produce great deformation, lower connecting rod 3 alright in order to exert great pretightning force to axle bush C, thereby reduced the risk of axle bush C separation.

In the embodiments of the present invention , referring to fig. 3, 7, 12, 14-15, the upper connecting rod 31 is provided with an upper central half-hole 316, the control connecting rod 32 is provided with a lower central half-hole 326, the upper central half-hole 316 and the lower central half-hole 326 surround a central hole 33, the adjustable connection point is a bolt connection point, the bolt connection point and the rotation connection point are distributed on the parting surfaces 40 at two sides of the central hole 33, the bolt connection point is provided with a connecting rod bolt 35, the adjusting force can be changed by changing the tightening degree of the connecting rod bolt 35, so as to change the pre-tightening force applied to the bearing bush C by the lower connecting rod 3.

In the embodiments of the present invention, the hinge seat 51 is disposed at the end of the parting surface 40, the boss 37 is disposed on the parting surface 40 on the side of the hinge seat 51 , as shown in fig. 25, the hinge seat 51 is disposed on the control link 32, the boss 37 and the hinge seat 51 both extend from the parting surface 40 of the control link 32 and extend toward the parting surface 40 of the upper link 31, and when the upper link 31 and the control link 32 are assembled and the connecting rod bolt 35 at the adjustable connecting point is tightened, the boss 37 and the parting surface 40 of the upper link 31 are deformed by contact, so as to increase the pre-tightening force of the lower link 3 on the bearing bush C.

In another embodiments of the present invention, the connecting arm 52 is disposed at the end of the parting surface 40, the boss 37 is disposed on the parting surface 40 located at the 52 side of the connecting arm 52, as shown in fig. 22-24, the connecting arm 52 is disposed on the upper connecting rod portion 31, the boss 37 and the connecting arm 52 both extend from the parting surface 40 of the upper connecting rod portion 31 and extend toward the parting surface 40 of the control connecting rod portion 32, and when the connecting rod bolt 35 at the adjustable connecting point is tightened after the upper connecting rod portion 31 and the control connecting rod portion 32 are assembled, the contact between the boss 371 of the reaming seat and the parting surface 40 of the control connecting rod portion 32 is deformed to increase the pretightening force of the lower connecting rod 3 on the bearing bush C.

In other embodiments of the present invention, the reaming base 51 and the connecting arm 52 both extend from the corresponding parting surface 40, and the boss 37 includes a reaming base boss 371 and a connecting arm boss 372, the reaming base boss 371 extends from the parting surface 40 where the reaming base 51 is located, and the connecting arm boss 372 extends from the parting surface 40 where the connecting arm 52 is located, that is, the boss 37 is disposed on the parting surface 40 where the reaming base 51 and the connecting arm 52 are located, for example, the reaming base 51 and the reaming base boss 371 are disposed on the parting surface 40 of the control connecting rod portion 32, the connecting arm 52 and the connecting arm boss 372 are disposed on the parting surface 40 of the upper connecting rod portion 31, and when the connecting rod bolt 35 at the adjustable connecting point is screwed down after the upper connecting rod portion 31 and the control connecting rod portion 32 are assembled, the reaming base boss 371 and the connecting arm boss 372 contact each other to deform, so as to increase the pretightening force of the lower connecting rod 3 on the bearing bush C.

In the embodiments of the present invention, as shown in fig. 27-28, the lower link 3 further includes the bearing bushes C respectively disposed in the upper link portion 31 and the control link portion 32, the two bearing bushes C are mounted in the central hole 33 in a relatively fastening manner, and as shown in fig. 25-26, the thickness of the boss 37 is not less than the height 91 of the remainder of the corresponding bearing bush C, thereby ensuring that the boss 37 can deform when the adjusting force for adjusting the adjustable connecting point is applied, so as to pre-tighten the bearing bush C, specifically, the bearing bush C disposed in the upper link portion 31 is the upper bearing bush 81, the bearing bush C disposed in the control link portion 32 is the lower bearing bush 82, and taking the control link portion 32 as an example, the thickness of the boss 37 on the parting surface 40 of the control link portion 32 is not less than the height 91 of the remainder of the lower bearing bush 82.

In the embodiments of the present invention, the bosses 37 are elongated bosses 37 for easy machining, and the length direction of the bosses 37 is parallel to the axis of the central hole 33. the number of the bosses 37 is at least .

According to another aspect embodiments of the present invention, the lower connecting rod 3 of the above embodiment is included, compared with the prior art, the engine of the present invention has the following advantages:

(1) the engine, after adopting above-mentioned lower connecting rod 3, because the at least tie points of upper connecting rod portion 31 and control link portion 32 are the rotation tie point, made things convenient for the assembly of lower connecting rod 3 and bent axle 4 from this to can improve the atress of lower connecting rod 3.

(2) The engine, set up boss 37 through 40 departments of the die joint of ends that rotate to be connected at last connecting rod portion 31 and control link portion 32, can realize axle bush C pretension, reduce the risk of axle bush C separation.

Referring to fig. 1 to 5 and 25 to 28, an upper bearing bush 81 is disposed between the upper center half hole 316 and the connecting rod neck 42, a lower bearing bush 82 is disposed between the lower center half hole 326 and the connecting rod neck 42, the upper bearing bush 81 and the lower bearing bush 82 are mounted in the central hole 33 of the lower connecting rod 3 in a relatively engaging manner, and before the upper connecting rod portion 31 and the control connecting rod portion 32 are assembled, the height 91 of the upper bearing bush 81 and/or the height 91 of the lower bearing bush 82 is greater than 0, that is, only the height 91 of the upper bearing bush 81 may be greater than 0, only the height 91 of the lower bearing bush 82 may be greater than 0, and both the heights 91 of the upper bearing bush 81 and the lower bearing bush 82 may be greater than 0. For convenience of description, only the above-mentioned example in which the height 91 of the remaining surface of the upper bush 81 and the lower bush 82 is greater than 0 is described below.

By increasing the height 91 of the residual surface of the upper bearing bush 81 and the lower bearing bush 82, the assembling pretightening force of the upper bearing bush 81 and the lower bearing bush 82 is increased, the joint rate of the upper bearing bush 81 and the lower bearing bush 82 is increased, and the failure risk caused by the separation of the upper bearing bush 81 and the lower bearing bush 82 is reduced.

According to the utility model discloses an engine sets up to all being greater than 0 through the remaining face height 91 with upper bearing bush 81 and lower bearing bush 82 to, can increase the assembly pretightning force of upper bearing bush 81 and lower bearing bush 82 to increased the laminating rate of upper bearing bush 81 and lower bearing bush 82, reduced the separation risk of upper bearing bush 81 and lower bearing bush 82.

In the embodiments of the present invention, the upper link portion 31 is provided with an upper link pin hole 311, the upper link pin hole 311 is hinged to the upper link 2, the control link portion 32 is provided with a control link pin hole 321, and the control link pin hole 321 is hinged to the control link 5.

, the upper link portion 31 and the control link portion 32 have two connecting points to fix the upper link portion 31 and the control link portion 32, and the two connecting points are located at two sides of the connecting line between the upper link pin hole 311 and the control link pin hole 321.

In the embodiments shown in fig. 3-4, 7, 12-16, of the connection points are rotational connection points and another of the connection points are threaded connection points.

In some embodiments not shown, both connection points are rotational connection points.

In other embodiments, not shown, both connection points are bolted connection points.

In embodiments of the present invention, the height 91 of the upper bearing bush 81 and the lower bearing bush 82 is 60 μm to 100 μm.

Meanwhile, the increase of the pretightening force of the bearing bush C can lead to the increase of the stress deformation of the upper bearing bush 81 and the lower bearing bush 82, and the whole thickness of the bearing bush C should be correspondingly increased in order to reduce the deformation of the upper bearing bush 81 and the lower bearing bush 82. in the embodiments of the present invention, the thickness of the upper bearing bush 81 and the lower bearing bush 82 is 1.6mm to 2mm, and the deformation of the upper bearing bush 81 and the lower bearing bush 82 can be reduced by increasing the thickness of the upper bearing bush 81 and the lower bearing bush 82.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The types of lower connecting rods (3) are characterized in that a central hole (33) matched with a crankshaft (4) is formed in each lower connecting rod (3), each lower connecting rod (3) comprises an upper connecting rod part (31) and a control connecting rod part (32), at least end of the connection position of the upper connecting rod part (31) and the control connecting rod part (32) is hinged and connected through a hinge pin (53), an upper connecting rod pin hole (311) suitable for being rotatably connected with an upper connecting rod (2) is formed in each upper connecting rod part (31), a projection area (Q) is formed in each upper connecting rod pin hole (311) in the direction parallel to the length of the upper connecting rod (2), and when an engine is at the maximum explosive pressure, each hinge pin (53) is located in each projection area (Q).
2. 2. The lower connecting rod (3) according to claim 1, wherein a parting plane (40) is formed between the upper connecting rod part (31) and the control connecting rod part (32), an upper center half hole (316) is formed in the upper connecting rod part (31), a lower center half hole (326) is formed in the control connecting rod part (32), the upper center half hole (316) and the lower center half hole (326) surround a center hole (33), and the parting plane (40) is arranged to penetrate through the axis of the center hole (33).
3. 3. A lower connecting rod (3) according to claim 2, characterized in that the axis of the hinge pin (53) lies in the plane of the parting plane (40).
4. 4. The lower connecting rod (3) according to claim 2, wherein the control connecting rod part (32) is provided with a control connecting rod pin hole (321), and the central connecting line of the upper connecting rod pin hole (311) and the control connecting rod pin hole (321) and the parting plane (40) form an included angle theta which satisfies the following conditions: theta is more than or equal to 45 degrees and less than or equal to 65 degrees.
5. 5. A lower connecting rod (3) according to claim 2, characterized in that a region between the projection region (Q) and the central bore (33) is provided with a reinforcement (38).
6. 6. The lower connecting rod (3) according to claim 5, characterized in that there is an interference region between the projected area (Q) and the central bore (33), the stiffener (38) being located at least partially within the projected area (Q) between the interference region and the upper connecting rod pin bore (311).
7. 7. A lower connecting rod (3) according to claim 6, characterized in that the interference area does not exceed 1% of the maximum contribution of the central bore (33).
8. 8. The lower link (3) according to claim 1, characterized in that of the connection points of the upper link portion (31) and the control link portion (32) are bolted connection points that are located outside the projection area (Q).
9. 9. The lower connecting rod (3) of claim 2, wherein the inner surfaces of the upper central half bore (316) and the lower central half bore (326) are provided with a wear resistant coating.
10. 10, an engine, comprising:

    a piston (1), said piston (1) being adapted to move within a cylinder of said engine;

    a crankshaft (4), a main journal (41) of the crankshaft (4) being rotatably provided on a cylinder block of the engine;

    the lower connecting rod (3) according to of any of claims 1-9, the lower connecting rod (3) being fitted over a connecting rod journal (42) of the crankshaft (4);

    the upper connecting rod (2), the said upper connecting rod (2) is connected between said piston (1) and said lower connecting rod (3);

    a compression ratio adjustment mechanism (7), the compression ratio adjustment mechanism (7) for adjusting the position of the piston (1) within the cylinder, the compression ratio adjustment mechanism (7) comprising: the control connecting rod (5), the control connecting rod (5) with lower connecting rod (3) are articulated.

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