CN110671201A - Worm and gear driven mechanism with variable connecting rod length and variable compression ratio - Google Patents

Abstract

The invention discloses a turbine worm driving type variable connecting rod length and variable compression ratio mechanism, which comprises a connecting rod small end, an eccentric connecting rod bush, a worm, a driven gear, a driving motor, a connecting rod body, a bearing end cover, a bearing and the like, and is characterized in that: the eccentric connecting rod bushing is arranged in a small end hole of the connecting rod, an eccentric hole of the eccentric connecting rod bushing is used for installing a piston pin, a worm is arranged in a round hole processed in the small end of the connecting rod, the worm is meshed with an arc gear at the middle position of the eccentric connecting rod bushing to form a worm and gear transmission system, a driving motor is arranged in a connecting rod body and is controlled by an electric control system, the driving motor drives the worm and gear system through the gear transmission system to enable the eccentric connecting rod bushing to rotate, the linear distance from the axis of the piston pin hole to a crankshaft neck is further changed, and the length of the connecting rod is changed, so.

Description

A worm-driven variable link length variable compression ratio mechanism

technical field

The invention relates to a vehicle engine component, more specifically, a turbine worm drive type variable link length variable compression ratio mechanism.

Background technique

There is still huge potential in the production and ownership of automobiles, which also brings opportunities and challenges to the development of engines. Although new energy vehicles have emerged in recent years, they still cannot shake the market of mainstream internal combustion engine vehicles. Internal combustion engines have the advantages of light weight, high energy density, high thermal efficiency, good fuel adaptability, and reliable performance. At present, most engines still use petroleum products as the main fuel source. Therefore, with the increase of car ownership year by year, the energy security problem is more severe, and higher requirements are also placed on the engine. There are many factors affecting the thermal efficiency of the internal combustion engine. Among them, the compression ratio is an important factor affecting the thermal efficiency and fuel economy of the engine. The compression ratio of the engine refers to the ratio of the cylinder volume when the piston moves to the bottom dead center to the cylinder volume when the piston moves to the top dead center. Increasing the compression ratio can effectively improve the thermal efficiency of the engine. Under normal circumstances, the higher the compression ratio of the engine, the longer the piston work stroke, the more work, and the greater the output power. However, an excessive compression ratio in a gasoline engine will cause uncontrollable combustion, thereby damaging the engine, and knocking is prone to occur when the load is relatively large; an excessive compression ratio in a diesel engine will make the cylinder pressure of the diesel engine too high, resulting in increased vibration and noise. The impact load to be endured by the moving parts increases, thus affecting the working reliability and service life of the diesel engine.

In order to avoid the above situation, the variable compression ratio technology is introduced, which is considered to be one of the most effective means to improve the thermal efficiency of the engine and improve the fuel economy. Than, reduce gasoline engine knock and diesel engine work rough.

Using variable compression ratio technology can:

1. The combustion of the engine is optimized, and the larger compression ratio is adopted under partial load, which reduces the residual coefficient of exhaust gas and improves the thermal efficiency of combustion.

2. It enhances the adaptability of the engine to fuel. Generally speaking, for gasoline engines, specific models need to be added with a specific type of gasoline to ensure that no knocking occurs, and high-grade gasoline is expensive and uses variable compression. After the technology is compared, because the deflagration can be controlled by means of technical means, the gasoline of lower grade can be selected. From this point of view, the economy is also improved.

3. It is beneficial to improve the turbocharging performance of the supercharged gasoline engine. Due to the low speed and low exhaust energy during the starting process of the supercharged gasoline engine, the turbocharging system does not intervene at low speeds. The use of variable compression ratio technology can undoubtedly increase the exhaust energy and help the turbocharging system. Intervene quickly.

4. It is convenient for engine miniaturization and lightweight design.

SUMMARY OF THE INVENTION

In view of the existing technical problems, the present invention proposes a worm-driven variable connecting rod length variable compression ratio mechanism, which has reliable operation, small changes in parts, and low R&D cost. Specifically, when the crankshaft position sensor detects When the piston top dead center position signal, the electronic control system controls the rotation of the motor to drive the gear transmission system and then drives the worm gear transmission system to change the eccentric position of the piston pin hole, change the distance between the piston pin and the crank pin, and then bring the length of the connecting rod to change, thus To achieve the purpose of changing the compression ratio. However, the present invention only involves changing the compression ratio of two stages, and cannot achieve the effect of infinitely variable compression ratio.

To achieve the above object, the technical scheme adopted in the present invention is:

A turbine-worm drive type variable link length variable compression ratio mechanism comprises a connecting rod small end, an eccentric connecting rod bushing, a worm, a driven gear, a driving gear, a driving motor, a connecting rod body, a bearing end cover and a bearing. It is characterized by:

The eccentric connecting rod bushing is installed in the small end hole of the connecting rod, the eccentric hole of the eccentric connecting rod bushing is used to install the piston pin, the small end of the connecting rod is connected with the connecting rod body through threads, and the connecting rod body is internally processed. The driving motor is installed in the blind hole, the output shaft of the driving motor is connected with the driving gear, the driving gear is positioned through two bearings, the driving gear and the driven gear are meshed with each other, the lower end shaft of the worm is connected with the driven gear, and the worm is installed on the small end of the connecting rod for machining In the round hole of the worm, the upper and lower ends of the worm are fixed in position by the bearing and the bearing end cover, and the worm meshes with the arc gear processed on the outside of the eccentric connecting rod bushing.

The worm drive type variable connecting rod length variable compression ratio mechanism is characterized in that the center of the piston pin hole of the eccentric connecting rod bushing is not concentric with the outer circle center of the eccentric connecting rod bushing, and the outer circle is not concentric. The distance between the center of the circle and the center of the piston pin hole is d, and an arc gear is machined along the circumference at the middle position of the eccentric connecting rod bushing, and the tooth tip circle diameter of the gear is smaller than the outer diameter of the eccentric connecting rod bushing.

The worm-driven variable connecting rod length variable compression ratio mechanism is characterized in that the small end of the connecting rod is machined with a circular hole for installing the worm, the driving gear and the driven gear, through the bearing or the bearing. The end caps locate the gear and the worm.

The worm-driven variable connecting rod length variable compression ratio mechanism is characterized in that the connecting rod is divided into two parts, one part is the small end of the connecting rod, and the other part is the connecting rod body, and the two parts pass through the connecting rod. Threaded connection.

The worm drive type variable link length variable compression ratio mechanism is characterized in that the worm and the arc gear in the middle of the eccentric link bush form a worm gear transmission system, and at the same time use the worm to fix the position Locate the eccentric link bushing.

The worm-driven variable link length variable compression ratio mechanism is characterized in that the link body has a built-in drive motor, the output shaft of the drive motor is connected with the driving gear, and the driving gear is meshed with the driven gear, The driven gear is connected with the worm shaft, and the turbine worm drive system is driven by the drive motor, and the motor is controlled by the electronic control system.

In the described variable compression ratio piston connecting rod assembly driven by an eccentric bushing, the piston pin hole of the eccentric connecting rod bushing is in interference fit with the piston pin, and the clearance between the eccentric connecting rod bushing and the small end hole of the connecting rod is Cooperate. The inside of the piston has a square hole on the side of the active eccentric shaft sleeve, and the worm is installed in the square hole to cooperate with the gear in the middle of the active eccentric shaft sleeve.

Compared with the prior art, the beneficial effects of the present invention are:

1. A turbine-worm-driven variable link length variable compression ratio mechanism according to the present invention is composed of eccentric link bushings, worms, gears, motors and other components, and has a simple structure and is easy to process and install.

2. The turbine-worm drive type variable connecting rod length variable compression ratio mechanism according to the present invention only changes the structure of the upper half of the connecting rod, which avoids the modification of large parts such as the cylinder head, the body, and the crankshaft, which reduces the design cost.

Description of drawings

Below in conjunction with accompanying drawing, the present invention is further described:

FIG. 1 is a front cross-sectional view of the variable-length link variable compression ratio mechanism at a high compression ratio.

FIG. 2 is a front cross-sectional view of the variable length link variable compression ratio mechanism at a low compression ratio.

3 is a front cross-sectional view of an eccentric link bush.

Figure 4 is a side view of the eccentric link bushing.

FIG. 5 is an enlarged schematic cross-sectional view of FIG. 1B .

FIG. 6 is an enlarged schematic cross-sectional view of FIG. 1A

Description of reference numbers:

1 small end of connecting rod, 2 eccentric connecting rod bushing, 3 worm, 4 driven gear, 5 driving gear, 6 driving motor, 7 connecting rod body, 8 bearing end cover, 9 bearing.

Detailed ways

The present invention will be described in detail below according to the description of the accompanying drawings. The present invention is described as a preferred embodiment among many embodiments.

As shown in Figure 1, Figure 3 and Figure 4, the connecting rod eccentric bushing 2 is a cylindrical structure with a piston pin hole. The center of the piston pin hole does not coincide with the outer circle center of the connecting rod eccentric bushing 2. The parallel distance between them is d, and the connecting rod eccentric bushing 2 is machined with a circle of arc gears in the middle as shown in the figure. The diameter of the tooth tip circle of the gear is smaller than the outer diameter of the eccentric connecting rod bushing 2. The worm 3 is meshed and combined to form a worm gear and worm transmission system. Because the gear is processed on the connecting rod eccentric bushing 2, it can drive the connecting rod eccentric bushing 2 to rotate. Do location targeting.

As shown in Figure 1, Figure 5 and Figure 6, the connecting rod is divided into two parts, one part is the connecting rod small head 1, and the other is the connecting rod body 7. The two parts are connected by threads, and the two parts are divided into two parts for the convenience of processing. The blind hole for the drive motor 6 and the round hole for the bearing 9 are machined inside the connecting rod body 7, and the small end 1 of the connecting rod is machined with a round hole for placing the worm 3, the driving gear 5 and the driven gear 4, and the output shaft of the driving motor 6. Connected with the driving gear 5, the driving gear is positioned by the upper and lower two bearings 9, the two bearings 9 are respectively installed in the connecting rod body 7 and the circular hole of the connecting rod small end 1, the driving gear 5 and the driven gear 4 are meshed with each other For force transmission, the lower shaft of the worm 3 is combined with the driven gear 4, and the driven gear 4 is fixed in position under the action of the lower shaft of the worm 3, the bearing 9 and the bearing end cover 8, and the upper shaft of the worm is in the bearing 9 and the bearing end. Under the joint action of the cover 8, the position is fixed, and the rotation of the drive motor 6 drives the worm 3 to rotate.

As shown in Figure 1 and Figure 2, the engine is in a state of high compression ratio, the worm gear system does not work, the small end of the connecting rod 1, the eccentric connecting rod bushing 2, the worm shaft 3, and the three remain relatively static, and the piston pin hole The center of the circle is above the center of the outer circle of the eccentric connecting rod bushing 2, and the parallel distance between the two centers is d, which is called the eccentric distance. The process of converting an engine from a high compression ratio to a low compression ratio. At the top dead center position of the power stroke, the drive motor 6 works under the control of the electronic control system. The drive motor 6 first drives the gear transmission system and then drives the worm 3 to rotate through this system. Meshing, drives the eccentric connecting rod bushing to rotate, the eccentric connecting rod bushing 2 rotates 180 degrees, so that the position of the piston pin hole moves from the dotted line position to the solid line position, then the motor stops working, the worm gear system self-locks, and the length of the connecting rod changes. , the engine completes the transition from a high compression ratio to a low compression ratio.

Claims (7)

1. A worm and gear driven variable connecting rod length variable compression ratio mechanism comprises a connecting rod small end (1), an eccentric connecting rod bush (2), a worm (3), a driven gear (4), a driving gear (5), a driving motor (6), a connecting rod body (7), a bearing end cover (8) and a bearing (9), and is characterized in that the original connecting rod bush is designed into the eccentric connecting rod bush (2) to be installed in a hole of the connecting rod small end (1), an eccentric hole of the eccentric connecting rod bush (2) is used for installing a piston pin, the connecting rod small end (1) is connected with the connecting rod body (7) through a thread, the driving motor (6) is installed in a blind hole processed inside the connecting rod body (7), an output shaft of the driving motor (6) is connected with the driving gear (5), the driving gear (5) is positioned through two bearings (9), and the driving gear (5) is meshed with the driven gear (4, a lower end shaft of the worm (3) is connected with the driven gear (4), the worm (3) is installed in a circular hole machined in the small end (1) of the connecting rod, the upper end and the lower end of the worm (3) are fixed in position through a bearing (9) and a bearing end cover (8), and the worm (3) is meshed with an arc gear machined in the outer side of the eccentric connecting rod bushing (2).

2. The worm and gear driven variable connecting rod length variable compression ratio mechanism as claimed in claim 1, characterized in that the center of the piston pin hole of the eccentric connecting rod bush (2) is not concentric with the center of the outer circle of the eccentric connecting rod bush (2), the distance between the center of the outer circle and the center of the piston pin hole is d, an arc gear is machined along the circumference at the middle position of the eccentric connecting rod bush (2), and the diameter of the top circle of the gear is smaller than the diameter of the outer circle of the eccentric connecting rod bush (2).

3. The worm and gear driving type variable connecting rod length and compression ratio mechanism as claimed in claim 1, characterized in that the small end (1) of the connecting rod is provided with a round hole for mounting the worm (3), the driving gear (5) and the driven gear (4), and the gear and the worm (3) are positioned through a bearing (9) or a bearing end cover (8).

4. The worm gear and worm drive type variable connecting rod length and compression ratio mechanism as claimed in claim 1, wherein the connecting rod is divided into two parts, one part is the small connecting rod head (1) and the other part is the connecting rod body (7), and the two parts are connected through threads.

5. The worm-and-gear drive type variable link length and compression ratio mechanism as claimed in claim 1, wherein the worm gear (3) and the arc gear at the middle position of the eccentric link bush (2) form a worm-and-gear (3) transmission system, and the eccentric link bush (2) is positioned by utilizing the fixed position of the worm gear (3).

6. The worm and gear driven variable connecting rod length and variable compression ratio mechanism as claimed in claim 1, characterized in that the connecting rod body (7) is internally provided with a driving motor (6), an output shaft of the driving motor (6) is connected with a driving gear (5), the driving gear (5) is meshed with a driven gear (4), the driven gear (4) is connected with a worm shaft (3), and a worm and gear transmission system is driven by the driving motor (6).

7. The eccentric bushing driven variable compression ratio piston and connecting rod assembly according to claim 1, wherein the piston pin hole of the eccentric connecting rod bushing (2) is in interference fit with the piston pin, and the eccentric connecting rod bushing (2) is in clearance fit with the connecting rod small end (1) hole.

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