WO2015085854A1

WO2015085854A1 - Four-stroke engine

Info

Publication number: WO2015085854A1
Application number: PCT/CN2014/091860
Authority: WO
Inventors: 孔钊; 郭宁; 冯可亚; 吴永东
Original assignee: 苏州科瓴精密机械科技有限公司
Priority date: 2013-12-11
Filing date: 2014-11-21
Publication date: 2015-06-18
Also published as: CN103835782B; CN103835782A

Abstract

A four-stroke engine includes a cylinder (7), an oil pan (1), a crankcase (2), a transmission room (3) and a rocker chamber (4). The transmission room (3) is located on the side of the cylinder. A cam (6) and a big belt wheel (5) are provided above the transmission room (3), and a small belt wheel is provided below the transmission room (3). A driving belt is set between the big belt wheel (5) and the small belt wheel. The rocker chamber (4) is located on the cylinder. Multiple baffle-oil plates (8, 9) are provided between the transmission room (3) and the rocker chamber (4) and form a turning oil channel between the transmission room (3) and the rocker chamber (4). The engine utilizes the baffle-oil plates to form a labyrinth turning oil channel, which makes the lubricating oil mist enter into the rocker chamber through the turning oil channel, while the large amount of liquid lubricant is blocked by the baffle-oil plates, so that the amount of lubricant entered into the rocker chamber is significantly reduced, and the engine lubricating system can obtain a good circulation.

Description

Four-stroke engine

Technical field

The invention relates to a four-stroke engine.

Background technique

Hand-held or backpack-type work tools such as lawn mowers and lawn mowers, such as lawn mowers and lawn mowers, usually use an engine as a power source. Currently, widely used engines are usually two-stroke and four-stroke small-purpose engines. The demand for replacing the engine from two-stroke to four-stroke engines is increasing as the pollutant discharge regulations become more stringent. However, the four-stroke engine has a more complex lubrication system, so a stable and reliable lubrication system for small four-stroke The size, weight and operational stability of the engine have an important impact. The overhead cam engine in the small four-stroke engine has the advantages of high speed and low vibration. Therefore, more and more manufacturers develop and use this type of engine, but since the overhead cam engine usually uses belt or chain transmission, the belt is located in the transmission room. However, the high-speed rotation of the belt will cause the lubricating oil of the transmission chamber to splash, which will bring a large amount of lubricating oil into the rocker arm chamber, causing too much lubricating oil in the rocker arm chamber and affecting the operation of the engine lubrication system. Existing overhead cam engines, such as the lubrication system of the Honda GX25 series engine, use the isolation of the transmission chamber and the rocker chamber, that is, the lubricating oil does not flow into the rocker chamber through the transmission chamber. While other lubrication systems use the transmission chamber and the rocker chamber to communicate, there may be a problem of excessive lubrication of the rocker chamber.

Summary of the invention

In order to solve the problems of the prior art, the present invention provides a four-stroke engine capable of reducing the accumulation of lubricating oil in a rocker arm, which comprises a cylinder, an oil pan, a crankcase, a transmission chamber and a rocker chamber, the transmission chamber being located in the cylinder On the side, a cam and a large pulley are arranged above the transmission chamber, a small pulley is arranged below the transmission chamber, a transmission belt is arranged between the large pulley and the small pulley, the rocker chamber is located at the upper part of the cylinder, the transmission chamber and the shaking Arm A plurality of oil deflectors are disposed between the chambers, and the plurality of oil deflectors form a turning oil passage between the transmission chamber and the rocker chamber.

The following is an auxiliary technical solution of the present invention

Preferably, there are two oil baffles, which are a first oil baffle and a second oil baffle.

Preferably, the first oil deflector is located above the cam.

Preferably, the turning oil passage includes a first passage, an oil inlet gap and a second passage, and the oil inlet gap is located between the oil deflector and the cam.

Preferably, the first oil shield is between the first passage and the second passage.

Preferably, the first oil slinger comprises a flat plate and a vertical plate, and the flat plate is provided with a screw hole.

Preferably, the first oil baffle has a notch.

Preferably, the second oil deflector is integral with the cylinder.

Preferably, the second oil retaining plate is provided with a first shaft hole and a second shaft hole,

Preferably, the four-stroke engine includes a lubrication system including a transmission chamber and a rocker chamber, and the lubricating oil below the transmission chamber is delivered to the rocker chamber through the belt.

The technical effect of the invention is that the oil baffle is used to form the labyrinth overturning oil passage, so that the lubricating oil mist enters the rocker arm chamber through the turning oil passage, and a large amount of liquid lubricating oil is blocked by the oil retaining plate, thereby significantly reducing the entry into the rocker arm chamber. The amount of lubricant makes the engine lubrication system cycle well.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 2 is another cross-sectional view of a four-stroke engine in accordance with an embodiment of the present invention.

Figure 3 is a top plan view of a four stroke engine in accordance with an embodiment of the present invention.

4 is a schematic view of a four-stroke engine cylinder in accordance with an embodiment of the present invention.

Fig. 5 is a schematic view of an oil retaining plate according to an embodiment of the present invention.

detailed description

The invention will be further described below in conjunction with the accompanying drawings.

1 to 3 show a four-stroke engine according to an embodiment of the present invention, which is an overhead cam engine, which has a small volume and displacement, and is generally used for garden tools such as lawn mowers, lawn mowers, and repairs. Tools such as branches and scissors, but are not limited to the above fields. The four-stroke engine of the embodiment comprises: an oil pan 1, a crankcase 2, a transmission chamber 3, a rocker chamber 4 and a cylinder 7, the oil pan 1 is used for storing lubricating oil, and the crankcase 2 is located above the oil pan 1, and the crankcase is provided There is a crankshaft assembly for driving the piston to reciprocate, and the reciprocating motion of the piston causes a pressure change in the crankcase so that the lubricating oil can flow in the engine. The transmission chamber 3 is located on the side of the cylinder 7, and the transmission chamber is provided with a transmission belt (not shown). In the embodiment, the transmission belt is a belt. As those skilled in the art can understand, the transmission belt can also be a chain or other transmission-capable components. The drive belts are respectively sleeved on the large pulley 5 and the small pulley 4. A rocker arm chamber 4 is disposed in the upper portion of the cylinder 7, and a rocker arm assembly 42 is disposed in the rocker arm chamber 4 for controlling opening and closing of the valve 43. When the engine is running, the crankshaft assembly drives the small pulley 4 to rotate, and the rotation of the small pulley is transmitted to the large pulley 5 through the transmission belt, and the large pulley 5 drives the cam 6 to rotate, and the cam top pushes the rocker arm assembly to make the valve open regularly or shut down. In the present embodiment, the large pulley 5 and the cam 6 are integral. The lubrication system of the four-stroke engine of the present embodiment includes an oil pan, a crankcase, a transmission chamber, and a rocker chamber, and the lubricating oil circulates in the lubrication system while the machine is running. When the piston moves from the bottom dead center to the top dead center, a negative pressure is generated, and the lubricating oil in the oil pan 1 enters the oil passage between the oil pan and the crankcase under the action of the negative pressure, and a part of the lubricating oil in the oil passage enters. The crankcase, another part enters the transmission chamber, and the lubricating oil in the transmission chamber is continuously delivered to the rocker chamber through the belt. The power of the lubricating oil cycle in this embodiment is derived from the pressure change of the crankcase, and those skilled in the art will appreciate that the above cycle can also be achieved by the use of an oil pump to provide power. In the prior art, there are many lubrication systems for overhead cam engines. As long as the lubricating oil is delivered to the rocker chamber through the transmission chamber, the technical solution of the oil retaining plate of the present invention can be used to achieve the purpose of controlling the amount of lubricating oil.

As shown in FIGS. 1 to 5, an oil retaining plate is disposed between the transmission chamber 3 and the rocker chamber 4, and the oil retaining plate has at least two pieces, which constitute a turning oil passage, so that the lubricating oil flows in the turning oil passage. Change while extending the flow path. In this embodiment, the oil baffle plate is provided with two blocks, which are a first oil baffle plate 8 and a second oil baffle plate 9, respectively, and the first oil baffle plate and the second oil baffle plate form a turning oil passage. The oil baffle shields the splashing oil from the transmission chamber to prevent excess lubricating oil from entering the rocker arm chamber 4; the turning oil passage extends the lubricating oil mist (the oil mist refers to a mixture including liquid and gaseous lubricating oil) from the transmission chamber to shake The flow path of the arm chamber causes a portion of the oil mist to liquefy in the turning oil passage, thereby reducing the oil mist concentration and reducing the oil mist concentration entering the rocker chamber. The turning oil passage includes a first passage 31, an oil inlet gap 81 and a second passage 41. The lubricating oil mist in the transmission chamber sequentially enters the rocker chamber 4 through the first passage 31, the oil inlet gap 81 and the second passage 41. The first passage 31 is located between the first oil deflector 8 and the large pulley 5, the oil inlet gap 81 is located between the first oil deflector 8 and the cam 6, and the second passage 41 is located at the second oil shield 9 and Between the first oil slabs 8. The lubricating oil mist of the transmission chamber passes through the first passage 31, bypasses the first oil deflector 8 through the oil inlet gap 81, and then enters the second passage 41. Those skilled in the art will appreciate that if the amount of lubricating oil entering the rocker chamber is further reduced, it can be achieved by increasing the number of oil baffles and extending the oil mist flow path, so that the improvement based on the present invention does not deviate from the present invention. . The first oil deflector 8 is disposed above the transmission chamber 3, and includes a flat plate 82 and a vertical plate 83. The flat plate 82 is provided with a screw hole 821, and the first oil retaining plate is fixed to the rocker chamber cover 44 by screws. The riser 83 is located above the cam 6. The riser 83 has a notch 84 which is an arcuate notch which prevents the cam 6 from interfering with the first baffle 8 when it rotates, affecting the cam rotation. It can be known to those skilled in the art that the shape of the first oil slinger can be other forms as long as it can realize the ability to block the lubricating oil. According to the specific structural limitation of the engine, the oil damper of other shapes or sizes can be used instead. It is an improvement that is apparent on the basis of the present invention. A second oil slinger 9 is disposed behind the first oil slinger 8. The second oil slab is substantially parallel to the vertical plate 83. The second time, the liquid lubricating oil splashing from the transmission chamber to the rocker chamber can be intercepted. Reduce liquid lubricant entering the rocker chamber, reduce cylinder oil return and condensation network (set at The device above the cylinder for condensing the lubricating oil, typically the load of the wire mesh). The second oil deflector 9 is provided with a first shaft hole 91 and a second shaft hole 92. The cam shaft and the rocker shaft are respectively disposed in the first and second shaft holes. The second oil slab 9 is integrated with the cylinder 7, which makes the structure simpler and the processability is good.

The invention utilizes a baffle plate to form a labyrinth-turning oil passage, so that the lubricating oil mist enters the rocker arm chamber through the turning oil passage, and a large amount of liquid lubricating oil is blocked by the oil retaining plate, thereby significantly reducing the amount of lubricating oil entering the rocker arm chamber. This allows the engine lubrication system to cycle well. It should be noted that the above-described preferred embodiments are merely illustrative of the technical idea and the features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention. protected range. Equivalent variations or modifications made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims

A four-stroke engine includes a cylinder, an oil pan, a crankcase, a transmission chamber and a rocker chamber. The transmission chamber is located at a side of the cylinder, a cam and a large pulley are arranged above the transmission chamber, and a small pulley is arranged below the transmission chamber. A transmission belt is disposed between the large pulley and the small pulley, and the rocker chamber is located at an upper portion of the cylinder, wherein: a plurality of oil retaining plates are disposed between the transmission chamber and the rocker chamber, and the plurality of oil retaining members The plate forms a turning oil passage between the transmission chamber and the rocker chamber.
A four-stroke engine according to claim 1, wherein said oil deflector has two, respectively a first oil deflector and a second oil deflector.
The four-stroke engine of claim 2 wherein said first oil deflector is located above the cam.
A four-stroke engine according to claim 3, wherein said turning oil passage includes a first passage, an oil inlet gap and a second passage, said oil inlet gap being located between the oil deflector and the cam.
A four-stroke engine according to claim 4, wherein said first oil passage plate is between said first passage and said second passage.
A four-stroke engine according to claim 2, wherein said first oil deflector comprises a flat plate and a riser, and said flat plate is provided with a screw hole.
A four-stroke engine according to claim 2, wherein said first oil stop has a notch.
A four-stroke engine according to claim 2, wherein said second oil deflector is integral with the cylinder.
A four-stroke engine according to claim 2, wherein said second oil retaining plate is provided with a first shaft hole and a second shaft hole,
A four-stroke engine according to any one of claims 1 to 9, wherein: The four-stroke engine includes a lubrication system including a transmission chamber and a rocker chamber, and the lubricating oil below the transmission chamber is delivered to the rocker chamber through the belt.