CN107956784A

CN107956784A - A kind of crank-connecting rod mechanism for engine

Info

Publication number: CN107956784A
Application number: CN201711188360.9A
Authority: CN
Inventors: 张春英; 杨凯; 陈雷雷; 徐明星; 鱼春燕; 顾丽; 居钰生; 夏少华; 易正根
Original assignee: FAW Group Corp
Current assignee: FAW Group Corp
Priority date: 2017-11-24
Filing date: 2017-11-24
Publication date: 2018-04-24

Abstract

A kind of crank-connecting rod mechanism for engine of the present invention, belongs to technical field of internal combustion engines.A kind of crank-connecting rod mechanism for engine, including piston, bent axle and the connecting rod of connection piston and bent axle, wherein, piston is placed in the cylinder of internal combustion engine, connecting rod is linked by piston pin and piston, bent axle by crank-pin and connection-rod linkage, the center line of the main bearing hole of the bent axle relative to cylinder center line positive bias, piston pin hole axis relative to cylinder center line negative bias.Present invention application can only substantially reduce abrasion and the vibrating noise of piston with a piston by the application of offset connecting rod, implementation method is simple, so as to reduce the friction loss of engine, the power of engine is improved, reduces piston purchase cost and the development cost of engine.

Description

A kind of crank-connecting rod mechanism for engine

Technical field

A kind of crank-connecting rod mechanism for engine of the present invention, belongs to technical field of internal combustion engines.

Background technology

When crank-connecting rod mechanism for engine is run in engine body, piston pumps, and tends in piston During upper and lower stop, the contact and shock of moment can occur as guiding role with piston-cylinder inner wall for piston skirt.Especially do Work(stroke top dead center, piston bear greatly explosion pressure and high temperature thermal deformation effect, and larger normal pressure is born in piston skirt And expansion, so as to cause serious friction and wear occurs between piston and cylinder sleeve.Meanwhile piston can also produced with cylinder sleeve Violent vibration and noise.Especially high load capacity, high-revolving engine, the fretting wear of piston skirt is even more serious, reduces The service life of piston.

The technological means of the reduction piston skirt fretting wear used at present is：

Firstth, low-friction coating technology is carried out in piston skirt and inboard wall of cylinder liner, but brought using this kind of means Shortcoming is the yield rate that more complicated coating process can reduce piston, greatly increases the processing cost of piston, and then engine Development cost is consequently increased.

Secondth, using the method for piston skirt asymmetric design, what method directly resulted in this is exactly structure processing technology It is more complicated, the processing cost of piston equally can be also greatly increased, and then the development cost of engine is consequently increased.

The content of the invention

The purpose of the present invention is only by improving the structure of crank-connecting rod mechanism for engine, by crankshaft center positive bias and work The biasing of plug pin hole combines, and reduces fretting wear and the vibrating noise of piston skirt, while improving the service life of piston, selects piston Uniformity with engine improves, so as to reduce engine development cost.

In order to realize above-mentioned technical purpose, the present invention uses following concrete technical scheme：

A kind of crank-connecting rod mechanism for engine, including piston, bent axle and the connecting rod of connection piston and bent axle, wherein, it is living Plug in the cylinder of internal combustion engine, connecting rod is linked by piston pin and piston, and bent axle is described by crank-pin and connection-rod linkage The center line of the main bearing hole of bent axle relative to cylinder center line positive bias, piston pin hole axis relative to cylinder center line Negative bias.

The center line of the main bearing hole of the bent axle relative to the center line of cylinder eccentric distance for 0mm~15mm it Between, the piston pin hole axis is relative to the eccentric distance of the center line of cylinder between -1mm~0mm.

The beneficial effects of the invention are as follows：

Compared with the method deposited at present, a kind of crank-connecting rod mechanism for engine of the present invention passes through piston pin hole bias and bent axle The piston skirt low friction abrasion that the combination of center bias solves independent piston pin hole bias or crankshaft eccentric can not be realized And the optimized design scheme of vibration absorbing low noise.

Meanwhile the mill of piston only can be substantially reduced by the application of offset connecting rod using with a piston Vibrating noise is undermined, implementation method is simple, so as to reduce the friction loss of engine, improves the power of engine, reduces work Fill in purchase cost and the development cost of engine.

Brief description of the drawings

Fig. 1 is a kind of structure diagram of crank-connecting rod mechanism for engine component of the present invention；

Fig. 2 is inventive piston pin hole bias illustraton of model；

Fig. 3 is crankshaft center arranged off-centre component model figure；

Fig. 4 is piston skirt and cylinder sleeve contact area schematic diagram；

Fig. 5 is 4000rpm, and bent axle is without biasing, piston oscillation figure when piston pin is without biasing；

Fig. 6 is 4000rpm, and bent axle positive bias 15mm, piston pin is without piston oscillation figure when biasing；

Fig. 7 is 4000rpm, piston oscillation figure when bent axle positive bias 15mm, piston pin negative bias 0.7mm；

Bent axle positive bias 15mm lower pistons are different when Fig. 8 is 4000rpm biases corresponding data graphs；

Wherein, 1 is piston pin hole axis；2 be the center line of cylinder；3 be the center line of crank spindle bearing bore；4 be bent axle Main bearing hole；5 be cylinder；A is the best region that piston skirt is contacted with cylinder sleeve；B is avoided excessively for piston skirt with cylinder sleeve Contact area；δ be piston pin hole axis and cylinder longitudinal center plane offset distance from；△ is in crank spindle bearing bore and cylinder longitudinal direction The eccentric distance in heart face.

Embodiment

As shown in Figure 1, when piston is from compression stroke top dead center to during working stroke transition, no biasing toggle Piston major thrust face direction, the head on the left of Fig. 1 pistons first contact with cylinder jacket, can cause greatly to tap.Especially at a high speed The engine of operating, this percussion not only result in the great noise of engine and vibration, and the destruction to piston crown is also pole Big.

As shown in Fig. 2, when bent axle positive bias, although piston is that head is contacted with cylinder sleeve, but contact force is obvious Reduce, can not only reduce the fretting wear of piston skirt, also reduce piston lateral force.

As shown in figure 3, by carrying out negative bias to piston pin hole, i.e., after the design of bias -0.7, it can be seen that piston Pivot angle changes.Piston skirt is first contacted with cylinder jacket, and the skirt section of piston not only good rigidity, has the function that guiding.Not only The percussion of piston can be substantially reduced, protective effect also is played to piston crown and piston ring.

Analysis is it can be seen that go the system schema that bent axle positive bias combination piston pin hole biases both to reduce crank above The friction of linkage and vibrating noise, and the reliability of piston can be improved.

1 data of table are that the engine of work, the crank connecting link machine of different bent axle positive bias schemes are pinpointed to a 3000rpm Structure carries out the calculating and contrast of frictionmean effective pressure.It is clear that when crankshaft center distinguishes positive bias 5,10,15, it is living Frictionmean effective pressure when filling in negative bias 0.7 can reduce 4.6%-9.3% than not biasing engine.Significant effect.

Table 1 be 3000rpm rotating speed toggle pistons frictionmean effective pressure, unit Pa

When piston is in engine in reciprocal operational process, when tending to upper and lower stop, piston skirt can occur with cylinder sleeve The collision of moment, the guiding role of piston skirt are ensuring that commutation and and cylinder of the piston between Main thrust face and Mi thrust face Trouble-free operation between set.Especially under acting top dead centre, powerful detonation pressure effect, head and the cylinder of piston are avoided as far as possible Set contact, it is no to cause it will cause piston ring torsional deformation stuck, cause pull-cylinder phenomena after sticking together.

As shown in figure 4, the region contacted between piston skirt and cylinder sleeve, a-quadrant belongs to the upper skirt of piston, rigidity It is good, belong to the best region that piston skirt is contacted with cylinder sleeve；B area is the skirt end of piston skirt, poor rigidity, mutability, no It is adapted to contact.The toggle of the invention can make between piston and cylinder sleeve contact area be in optimum contact region A. The invention can effectively reduce the fretting wear of piston skirt, improve the suitability and reliability of piston.The structure realization side Formula is simple, reduces the cost of engine development.

The influence of piston pin hole negative bias and crankshaft center positive bias to piston knock energy (exemplified by 4000rpm)：

As shown in figure 5, when piston is from compression stroke top dead center to during working stroke transition, no biasing toggle The head in piston major thrust face direction is first contacted with cylinder jacket, not only results in great percussion, and head and skirt section can Produce larger fretting wear.The engine especially to run at high speed, this percussion not only result in the great noise of engine And vibration, the destruction to piston crown are also great, greatly reduce the service life of piston.

As shown in fig. 6, when bent axle positive bias, crankshaft center is just moved to piston major thrust face, i.e. left side, piston crown and The frictional force in skirt section substantially reduces, so that, reduce the destructiveness to piston and cylinder sleeve.

As shown in fig. 7, by carrying out negative bias 0.7 to piston pin hole, piston pin hole is to Main thrust face, i.e., inclined on the left of piston Shiftingization.Piston skirt is first contacted with cylinder jacket, and the skirt section of piston not only good rigidity, has the function that guiding.It can substantially reduce The percussion of piston, also plays protective effect to piston crown, piston ring and cylinder sleeve.

Analysis is it can be seen that go the system schema that bent axle positive bias combination piston pin hole biases both to reduce crank above The friction of linkage, and the reliability of piston can be improved.Both the percussion vibration between piston and cylinder sleeve can have been reduced, also might be used To reduce the noise of engine.

As Fig. 8 shows, dotted line represents bent axle positive bias 15mm, the striking energy data of piston pin hole negative bias 0.7mm.Can be bright Aobvious to find out in whole circulation, the synthesis striking energy of bent axle positive bias 15mm, piston pin hole negative bias 0.7mm is not inclined less than piston Put, solid line in figure, and piston pin hole positive bias 0.7mm, dotted line curve, when striking energy.

The engine to run at high speed is particularly suitable for, the engine to run at high speed, the percussion of piston and cylinder sleeve accelerates hair The vibration of motivation and noise, the toggle scheme for selecting bent axle positive bias and piston pin hole negative bias at this time is optimal side Case.

Claims

1. a kind of crank-connecting rod mechanism for engine, including piston, bent axle and the connecting rod of connection piston and bent axle, wherein, piston It is placed in the cylinder of internal combustion engine, connecting rod is linked by piston pin and piston, and bent axle is existed by crank-pin and connection-rod linkage, its feature In：The center line of the main bearing hole of bent axle（3）Relative to the center line of cylinder（2）Positive bias, piston pin hole axis（1）Relative to The center line of cylinder（2）Negative bias.

A kind of 2. crank-connecting rod mechanism for engine according to claim 1, it is characterised in that：The base bearing of the bent axle The center line in hole（3）Relative to the center line of cylinder（2）Eccentric distance between 0mm ~ 15mm, the piston pin hole axis （1）Relative to the center line of cylinder（2）Eccentric distance between -1mm ~ 0mm.