CN202001132U

CN202001132U - Engine piston

Info

Publication number: CN202001132U
Application number: CN2010206965922U
Authority: CN
Inventors: 王磊; 黄鹏华; 罗珒
Original assignee: SAIC GM Wuling Automobile Co Ltd
Current assignee: SAIC GM Wuling Automobile Co Ltd
Priority date: 2010-12-31
Filing date: 2010-12-31
Publication date: 2011-10-05
Anticipated expiration: 2020-12-31

Abstract

The utility model provides an engine piston. The piston comprises a piston head, a piston skirt, a piston pin hole and a piston pin boss. The piston head is bowl-shaped, the periphery of the piston head comprises at least one air valve avoiding pit and at least one inclined conical surface, and the inclined conical surface is connected with the piston head through an arc. The piston skirt is provided with a graphite coating to bring convenience to defection, and in order to facilitate detecting and controlling of the size of the piston, a blank window of the graphite coating is reserved. The engine piston has the advantages that compression ratio of an engine is improved, simultaneously knockings are effectively avoided, power of the engine is increased, thermal efficiency and economical efficiency of the engine are improved, formation and combustion efficiency of gas mixture in a combustion chamber are improved, tensile damage of the piston is avoided, and deformation and tensile damage of the piston pin hole are avoided.

Description

A kind of engine piston

[technical field]

The utility model relates to technical field of internal combustion engines, relates in particular to a kind of engine piston.

[background technique]

Piston is one of critical component of motor, and its main effect is the gas pressure that bears in the cylinder, and this power is passed to connecting rod by wrist pin, to promote crankshaft rotating.Piston head and cylinder head, cylinder wall are formed the firing chamber jointly, and therefore piston-shaped design and combustion-chamber shape and compression ratio have direct relation, and it directly influences eddy current in the firing chamber, rolls the formation and the intensity of stream and burning.

Existing float petrol machine, mostly adopt flat head piston, manufacturing process is simple, but has that heat absorption area is little, compression ratio is less than normal, can't form than shortcomings such as high current field motions in the cylinder, prolonged period of combustion, reduced the constant volume degree that burns, made that the thermal efficiency of motor is on the low side.

The pre-atmospheric pressure that bears of piston is passed to connecting rod by wrist pin and piston pin boss, but the total bearing area of wrist pin is limited, so, surperficial pressure between wrist pin and the key seat is very high, and the relative velocity between wrist pin and the key seat is very low in addition, and the liquid lubrication oil film is difficult for forming, cause pulling of pin-and-hole easily, bending deflection is inharmonious mutually during the work of piston and wrist pin, may cause pin-and-hole distortion even key seat cracking, and the piston lubrication arts demand is constantly explored and improved.

Engine piston working life is the bottleneck in motor working life normally, how to design the engine piston of a high efficiency and durable, and then improves the efficiency of internal combustion engine and performance is a big problem of engine art.

[model utility content]

In order to solve the problems of the prior art, the utility model provides a kind of engine piston, described piston comprises piston head, piston skirt, piston pin hole, piston pin boss, described piston head is a bowl-type depression, and its top depth is 2.0mm to 4.0mm, and comprises around this top that at least one valve dodges hole and at least one tilted conical surface, described tilted conical surface is an inclination angle with the piston transverse section and cooperates with the cylinder head bottom surface, forms to squeeze the stream district.As embodiment of the present utility model, it is four that this valve is dodged the hole, be separately positioned on the position corresponding with the cylinder valve, this tilted conical surface is four, and exceed cylinder block upper surface 0.6mm～3.0mm and this tilted conical surface and be connected by circular arc, and the radius of circular arc is 4.0mm to 10.0mm with the bowl-type top.Described skirt section has lubricant coating, and what adopt in this is novel is graphite coating, detects for convenience, and this graphite coating leaves blank window, is convenient to the Detection ﹠ Controling to piston size.

As further improvement of the utility model, the piston pin boss inboard of this novel piston is designed to the curved surface of cutting sth. askew, and is set to the horn mouth shape in the piston pin hole inside upper surface.

As further improvement of the utility model, the bottom surface of described piston pin boss is provided with machined region, is used for machining control piston size, prevents that piston pin boss and crankshaft counter balance from interfering.

The beneficial effects of the utility model are: when improving engine compression ratio, effectively avoid the appearance of pinking, improve the firing chamber mixed gas and form and combustion efficiency, improve the thermal efficiency and engine power, prevent that the piston skirt from pulling, avoid the distortion of piston pin hole and pull.

[description of drawings]

Fig. 1 is the structural drawing at the engine piston top that provides of the utility model;

Fig. 2 is the vertical direction sectional drawing of engine piston Fig. 1 of providing of the utility model;

Fig. 3 is the horizontal cross-sectional view of piston Fig. 1 of providing of the utility model;

Fig. 4 is the worm's eye view of the engine piston that provides of the utility model;

Fig. 5 is the lubricant coating schematic representation in the engine piston skirt section that provides of the utility model.

[embodiment]

Below in conjunction with description of drawings and embodiment the utility model is further specified.

Be illustrated in figure 1 as the structural drawing at the engine piston top that the utility model provides: position 3 is the bowl-type design of this piston head among the figure, and 1,2,4,8 positions are tilted conical surface; 5,6 positions are the arc design that the bowl-type bottom connects tilted conical surface; The hole is dodged for valve in position 7.

Piston head adopts the bowl-type design, and bowl-type degree of depth h is 2.0mm～4.0mm, and this design has increased the piston head area effectively, the also corresponding increase of its heat absorption area, the heat discharge of energy accelerating piston helps reducing piston unit area heat load, the phenomenon of detonation of having avoided high compression ratio to bring.

Tilted

conical surface

1,2,4,8 is arranged on piston head, this tilted conical surface connects the bowl end of piston head by cambered surface, radius of arc is 4.0mm～10.0mm, tilted conical surface cooperates with the cylinder head bottom surface, and squeeze the stream district common the composition, and tilted conical surface and horizontal line are 12 °～20 °, adopt curving of castings transition between bowl-type bottom and the tilted conical surface, this design helps mixed gas and forms strong extruding flow in cylinder, and then quickens the velocity of combustion of inflammable mixture in the cylinder, improves engine thermal efficiency.

Piston crown is for dodging valve, avoid piston and valve to bump against, be provided with four valves in the intake and exhaust side and dodge the hole, the valve shown in the position 7 is dodged the hole and is adopted open by design, be its outer that directly is communicated with piston crown, other three valves are dodged the hole and are not adopted open by design.Because the intake valve diameter is bigger, also answer relative set more greatly so dodge the diameter in hole, thereby cause the air inlet side to dodge less thick between hole and the firepower off coast wall, in engine operation process, because wall approaches, the operating temperature height, operating mode is abominable, can produce piston material herein and ablate, so position 7 dodge the hole open by design, cancel piston material herein, avoid occurring piston material and ablate.

As Fig. 2, the vertical direction sectional drawing of Fig. 1 of the engine piston that provides for the utility model.

Position

6,2,5,4 among Fig. 2 is consistent with the sign position among Fig. 1 respectively, does not repeat them here.Position 9 is the piston pin hole inboard, the key seat of position 10 for cutting sth. askew, and h indicates the degree of depth of piston head bowl-type design, and this degree of depth is 2.0mm～4.0mm.

When piston is worked up and down, owing to be subjected to very large stress, bending deflection is inharmonious mutually when piston and wrist pin work, can in the key seat hole, cause serious edge load by upside, may cause the pin-and-hole permanent deformation even key seat is split, for this reason, in 9 technological designs of the inboard employing of pin-and-hole horn mouth, can effectively reduce upper edge load in the pin-and-hole, avoid pin-and-hole distortion and key seat crackle to occur.In order to alleviate piston weight to a certain extent, piston base adopts the chamfered design at position 10, and piston pin boss is designed to the ellipse shape of up big and down small handstand or trapezoidal, and this design can make full use of the effective pressure area of piston pin boss, reduce piston mass simultaneously, reduce the impulse force that inertia causes.

The horizontal cross-sectional view of the piston Fig. 1 that provides for the utility model as Fig. 3:

Position 3 is the bowl end of the bowl-type design of this piston head; Position 14 is a pin-and-hole.On this view,, do not repeat them here because each key points in design at Fig. 1, has corresponding the description among Fig. 2.

The worm's eye view of the engine piston that provides for the utility model as Fig. 4.

Position 11 is a machined region among the figure.When piston is positioned at lower dead center, the piston pin boss bottom is the shortest with the crankshaft counter balance distance, because the piston pin hole bottom is to be produced by casting, tolerance of size is bigger, and crankshaft counter balance is similarly the casting generation, and tolerance of size is bigger, two casting tolerance stack, tolerance can be bigger, in engine operation process, exists piston pin boss and crankshaft counter balance to interfere risk.For the machine fining-off is adopted in the piston pin boss bottom, in the piston pin boss bottom machined region 11 is set, thereby effectively guarantees the piston pin boss bottom size, avoid piston pin boss and crankshaft counter balance to interfere the appearance of failure mode.

As Fig. 5 for being the lubricant coating schematic representation in the engine piston skirt section that provides of the utility model.

Position 12 is a graphite coating among the figure, the wicket of position 13 for reserving.

When motor has just started, lubrication system does not also have proper functioning, can't form effective lubricant film between piston and the cylinder hole, be easy to occur the scuffing of cylinder bore problem between piston and the casing wall,, adopt graphite coating 12 in the piston skirt for avoiding the appearance of this situation, simultaneously, for abandoning graphite coating thickness for the influence of measuring piston skirt DN diameter, stay not graphitization of a wicket 13 in the skirt section, can directly measure piston diameter

Above content be in conjunction with concrete preferred implementation to further describing that the utility model is done, can not assert that concrete enforcement of the present utility model is confined to these explanations.For the utility model person of an ordinary skill in the technical field, under the prerequisite that does not break away from the utility model design, can also make some simple deduction or replace, all should be considered as belonging to protection domain of the present utility model.

Claims

1. the piston of a motor, comprise piston head, piston skirt, piston pin hole, piston pin boss, it is characterized in that: described piston head is the reentrant part of bowl-type, the side of this reentrant part includes at least one tilted conical surface, described tilted conical surface is an inclination angle with the piston transverse section and cooperates with the cylinder head bottom surface, forms to squeeze the stream district.

2. the piston of motor according to claim 1, it is characterized in that: described inclination angle is set to 12 °～20 °.

3. the piston of motor according to claim 1, it is characterized in that: described tilted conical surface is four, and exceeds cylinder block upper surface 0.6mm～3.0mm.

4. the piston of motor according to claim 1, it is characterized in that: described piston head also is provided with four valves and dodges the hole.

5. the piston of motor according to claim 1, it is characterized in that: described skirt section is provided with lubricant coating.

6. the piston of motor according to claim 5, it is characterized in that: described lubricant coating is a graphite coating.

7. according to the piston of claim 5 or 6 described motors, it is characterized in that: the wicket that does not have lubricant coating is left in described piston skirt.

8. the piston of motor according to claim 1, it is characterized in that: described piston pin hole inside upper surface is the horn mouth shape.

9. the piston of motor according to claim 1, it is characterized in that: described piston pin boss inboard is designed to the curved surface of cutting sth. askew.

10. the piston of motor according to claim 1, it is characterized in that: the bottom of described piston pin boss is provided with machined region, is used for the fine finishing of bottom size.

11. the piston of motor according to claim 1 is characterized in that: the described bowl-type piston head degree of depth is 2.0mm to 4.0mm.

12. the piston of motor according to claim 1 is characterized in that: it is the arc transition of 4.0mm to 10.0mm radius that described bowl-type piston base and described tilted conical surface adopt radius.