阅读说明：本技术 一种两缸水平对置发动机正时系统 (Two-cylinder horizontally-opposed engine timing system ) 是由 李业振 许敏 袁志远 谭子瑶 王燕 于 2020-06-30 设计创作，主要内容包括：本发明涉及发动机配气领域,公开了一种两缸水平对置发动机正时系统,其包括曲轴(1),曲轴链轮(2),凸轮轴链轮I(9),进气凸轮轴Ⅰ(8),凸轮轴链轮II(12),排气凸轮轴Ⅰ(11),正时链条Ⅰ(10),曲轴链轮(2)两端分别具有同轴的链齿Ⅰ(24)和链齿Ⅱ(25),链齿Ⅰ(24)与正时链条Ⅰ(10)以链传动的方式连接；链齿Ⅱ(25)以链传动的方式连接一圈正时链条Ⅱ(20)一端,正时链条Ⅱ(20)另一端以链传动的方式依次跨绕凸轮轴链轮III(22)和凸轮轴链轮IV(19),凸轮轴链轮III(22)同轴固接进气凸轮轴Ⅱ(21)；凸轮轴链轮IV(19)同轴固接排气凸轮轴Ⅱ(18)。本发明实现了两缸水平对置发动机配气机构及附件系统正时驱动。(The invention relates to the field of engine gas distribution, and discloses a two-cylinder horizontally-opposed engine timing system which comprises a crankshaft (1), a crankshaft sprocket (2), a camshaft sprocket I (9), an air inlet camshaft I (8), a camshaft sprocket II (12), an air outlet camshaft I (11) and a timing chain I (10), wherein two ends of the crankshaft sprocket (2) are respectively provided with a coaxial sprocket I (24) and a sprocket II (25), and the sprocket I (24) is connected with the timing chain I (10) in a chain transmission manner; the chain tooth II (25) is connected with one end of a circle of timing chain II (20) in a chain transmission mode, the other end of the timing chain II (20) sequentially strides around a camshaft chain wheel III (22) and a camshaft chain wheel IV (19) in a chain transmission mode, and the camshaft chain wheel III (22) is coaxially and fixedly connected with an air inlet camshaft II (21); the camshaft sprocket IV (19) is coaxially and fixedly connected with an exhaust camshaft II (18). The invention realizes the timing drive of the valve actuating mechanism and the accessory system of the two-cylinder horizontally-opposed engine.)

1. A two-cylinder horizontally opposed engine timing system, comprising:

a crankshaft (1), said crankshaft (1) being located between two cylinders of the engine;

the crankshaft chain wheel (2), the crankshaft chain wheel (2) is coaxially and fixedly connected with the crankshaft (1);

the camshaft chain wheel I (9) is arranged close to an air inlet valve of an air cylinder of the engine, and the camshaft chain wheel I (9) is coaxially and fixedly connected with an air inlet camshaft I (8) and used for controlling the opening or closing of the air inlet valve close to the air cylinder;

the camshaft chain wheel II (12) and the camshaft chain wheel I (9) are arranged close to the same cylinder, the installation position of the camshaft chain wheel II is closer to an exhaust valve, and the camshaft chain wheel II (12) is coaxially and fixedly connected with an exhaust camshaft I (11) and used for controlling the opening or closing of the exhaust valve close to the cylinder;

the crankshaft chain wheel (2), the camshaft chain wheel I (9) and the camshaft chain wheel II (12) are connected in a chain transmission mode through a circle of timing chain I (10), one end of the timing chain I (10) sequentially strides around the camshaft chain wheel I (9) and the camshaft chain wheel II (12), and the other end of the timing chain I (10) strides around the crankshaft chain wheel (2);

the method is characterized in that: the two ends of the crankshaft chain wheel (2) are respectively provided with a coaxial chain tooth I (24) and a coaxial chain tooth II (25), the number of the chain teeth I (24) is the same as that of the chain tooth II (25), and the chain tooth I (24) is connected with the timing chain I (10) in a chain transmission mode; the chain tooth II (25) is connected with one end of a circle of timing chain II (20) in a chain transmission mode, the other end of the timing chain II (20) sequentially strides around a camshaft chain wheel III (22) and a camshaft chain wheel IV (19) in a chain transmission mode, the camshaft chain wheel III (22) is installed close to an intake valve of another cylinder of the engine, and the camshaft chain wheel III (22) is coaxially and fixedly connected with an intake camshaft II (21) and used for controlling the intake valve of the cylinder close to the intake valve to be opened or closed; the camshaft sprocket IV (19) is coaxially and fixedly connected with an exhaust camshaft II (18) and is used for controlling the opening or closing of an exhaust valve close to the cylinder.

2. A two-cylinder horizontally opposed engine timing system as set forth in claim 1 wherein: a timing chain I (10) between the crankshaft chain wheel (2) and the camshaft chain wheel I (9) is connected into a balance shaft chain wheel (26) in a chain transmission mode, the balance shaft chain wheel (26) and a gear I (5) are coaxially and fixedly connected onto a balance shaft I (4), a timing chain I (10) between the crankshaft chain wheel (2) and the camshaft chain wheel II (12) is connected into another balance shaft chain wheel (26) in a chain transmission mode, the balance shaft chain wheel (26) and a gear II (15) are coaxially and fixedly connected onto a balance shaft II (14), and the gear I (5) is meshed with the gear II (15).

3. A two-cylinder horizontally opposed engine timing system as set forth in claim 2 wherein: and the shaft sections, close to the balance shaft chain wheel (26), of the balance shaft I (4) or the balance shaft II (14) are respectively provided with an eccentric balance block (30).

4. A two-cylinder horizontally opposed engine timing system as set forth in claim 3 wherein: and the shaft section of one end of the balance shaft I (4) or the balance shaft II (14) far away from the balance shaft chain wheel (26) is respectively provided with another eccentric balance block (30), and an included angle of 180 degrees is formed between the balance block (30) and the balance shaft chain wheel (26).

5. A two-cylinder horizontally opposed engine timing system as set forth in claim 4 wherein: the balance weight (30) is in a shape of removing the circle center area of the balance weight in a fan shape.

6. A two-cylinder horizontally opposed engine timing system as set forth in claim 5 wherein: a static guide rail III (3) is arranged between a balance shaft chain wheel (26) and a crankshaft chain wheel (2), wherein the balance shaft chain wheel (26) is connected with the upper portion of the timing chain I (10) in a chain mode, and a section of the timing chain I (10) between the balance shaft chain wheel (26) on the balance shaft I (4) and the crankshaft chain wheel (2) is cut in or cut out along the track of the static guide rail III (3).

7. A two-cylinder horizontally opposed engine timing system as set forth in claim 3 wherein: the timing chain I (10) is provided with a first tensioning device, the first tensioning device comprises a movable guide rail I (7), a static guide rail I (13) and a first tensioner (6), the movable guide rail I (7) is installed on a section of timing chain I (10) between a balance shaft chain wheel (26) and a camshaft chain wheel I (9) on the balance shaft I (4), the timing chain I (10) is cut into or cut out along the track of the movable guide rail I (7), one end of the movable guide rail I (7) is a fixed end and is installed close to the camshaft chain wheel I (9), the other end of the movable guide rail I (7) is a free end and is close to the balance shaft chain wheel (26) on the balance shaft I (4), the part between the fixed end and the free end of the movable guide rail I (7) protrudes downwards, and the section of the timing chain I (10) between the balance shaft chain wheel (26) and the camshaft chain wheel I (9) on the balance shaft I (4) is pressed down and tensioned, a first tensioner (6) is arranged at the free end of the movable guide rail I (7), the lower end of the first tensioner (6) is fixedly connected with the free end of the movable guide rail I (7) and can drive the free end of the movable guide rail I (7) to rotate by taking the fixed end of the movable guide rail I (7) as a shaft; the two ends of the static guide rail I (13) are fixed ends, one end of the static guide rail I (13) is installed close to the camshaft chain wheel II (12), the other end of the static guide rail I (13) is installed close to the balance shaft chain wheel II (26), a cutting-in or cutting-out of a timing chain I (10) between the balance shaft chain wheel (26) on the balance shaft II (14) and the camshaft chain wheel IV (19) is carried out along the track of the static guide rail I (13), the part between the two fixed ends of the static guide rail I (13) protrudes upwards, and the cutting-in timing chain I (10) between the balance shaft chain wheel (26) on the balance shaft II (14) and the camshaft chain wheel IV (.

8. A two-cylinder horizontally opposed engine timing system as set forth in claim 1 wherein: the timing chain I (10) is provided with a first tensioning device, the first tensioning device comprises a movable guide rail I (7), a static guide rail I (13) and a first tensioner (6), the movable guide rail I (7) is installed on a timing chain I (10) between a crankshaft chain wheel (2) and a camshaft chain wheel I (9), the timing chain I (10) is cut in or out along the track of the movable guide rail I (7), one end of the movable guide rail I (7) is a fixed end and is installed close to the camshaft chain wheel I (9), the other end of the movable guide rail I (7) is a free end and is close to the crankshaft chain wheel (2), the part between the fixed end and the free end of the movable guide rail I (7) downwards protrudes to press down and tension the timing chain I (10) between the crankshaft chain wheel (2) and the camshaft chain wheel I (9), the first tensioner (6) is installed on the free end of the movable guide rail I (7), the lower end of the first tensioner (6) is fixedly connected with the free end of the movable guide rail I (7), and can drive the free end of the movable guide rail I (7) to rotate by taking the fixed end of the movable guide rail I (7) as a shaft; the two ends of the static guide rail I (13) are fixed ends, one end of the static guide rail I (13) is installed close to the camshaft chain wheel II (12), the other end of the static guide rail I (13) is installed close to the crankshaft chain wheel II (2), a section of the timing chain I (10) between the crankshaft chain wheel (2) and the camshaft chain wheel IV (19) is cut in or cut out along the track of the static guide rail I (13), the part between the two fixed ends of the static guide rail I (13) protrudes upwards, and the section of the timing chain I (10) between the crankshaft chain wheel (2) and the camshaft chain wheel IV (19) is lifted and.

9. A two-cylinder horizontally opposed engine timing system as set forth in any one of claims 1-8, wherein: the timing chain II (20) is provided with a second tensioning device, the second tensioning device comprises a movable guide rail II (17), a static guide rail II (23) and a second tensioner (16), the movable guide rail II (17) is arranged between a crankshaft sprocket wheel (2) and a camshaft sprocket wheel IV (19) and is provided with a fixed end and a free end, the fixed end of the movable guide rail II is arranged close to the camshaft sprocket wheel IV (19), the free end of the movable guide rail II is close to the crankshaft sprocket wheel (2), the part between the fixed end and the free end of the movable guide rail II is in a convex shape so as to lift and tension a section of the timing chain II (20) between the crankshaft sprocket wheel (2) and the camshaft sprocket wheel IV (19), the timing chain II (20) between the crankshaft sprocket wheel (2) and the camshaft sprocket wheel IV (19) is cut in or cut out along a section of the movable guide rail II (17), and the free end of the movable guide rail II (17) is provided with, the second tensioner (16) is arranged below the movable guide rail II (17), the upper end of the second tensioner (16) is fixedly connected with the free end of the movable guide rail II (17), and the second tensioner (16) can drive the free end of the movable guide rail II (17) to rotate by taking the fixed end of the movable guide rail II (17) as a shaft; the two ends of the static guide rail II (23) are fixed ends, one end of the static guide rail II is close to the camshaft chain wheel III (22) and the other end of the static guide rail II is close to the crankshaft chain wheel (2), the part between the two ends of the static guide rail II is in a downward convex shape, and a cutting timing chain II (20) between the crankshaft chain wheel (2) and the camshaft chain wheel III (22) is cut in or out along the track of the static guide rail II (23).

10. A two-cylinder horizontally opposed engine timing system as set forth in claim 9 wherein: the first tensioner (6) and the second tensioner (16) are hydraulic tensioners.

Technical Field

The invention relates to the field of engine gas distribution, in particular to a two-cylinder horizontally-opposed engine timing system.

Background

The timing of the engine is an important component of an engine gas distribution system, and the accuracy of air inlet and exhaust time is ensured by connecting with a crankshaft and matching with a certain transmission ratio. With the continuous progress of the technical level and the industrial development, a part of timing belts of the engine is replaced by engine chains, and compared with the traditional belt drive, the chain drive mode has the advantages of reliable transmission, good durability and space saving. The chain timing system consists of a gear, a chain, a tensioning device and the like.

The engine is different from the traditional in-line engine which only has one cylinder cover, the two horizontally opposite cylinders of the engine are respectively provided with one cylinder cover at the left end and the right end in the horizontal direction, and each cylinder cover is provided with an independent valve actuating mechanism. Therefore, a two-cylinder horizontally-opposed engine needs a set of timing system which can drive and ensure that independent valve actuating mechanisms on the left side and the right side accurately operate according to given phase moments.

Disclosure of Invention

The present invention is directed to solving the above-mentioned problems of the prior art, and an object of the present invention is to provide a two-cylinder horizontally-opposed engine timing system, which can control intake and exhaust valves of a two-cylinder horizontally-opposed engine using chain transmission, and which can realize the advantages of the chain transmission in the two-cylinder horizontally-opposed engine valve timing system.

To solve the above problem, a two-cylinder horizontally opposed engine timing system is employed, which includes:

a crankshaft, the crankshaft being located between two cylinders of the engine;

the crankshaft chain wheel is coaxially and fixedly connected with the crankshaft;

the camshaft chain wheel I is arranged close to an air inlet valve of an air cylinder of the engine and is coaxially and fixedly connected with an air inlet camshaft I and used for controlling the opening or closing of the air inlet valve close to the air cylinder;

the camshaft chain wheel II and the camshaft chain wheel I are arranged close to the same cylinder, the installation position of the camshaft chain wheel II is closer to an exhaust valve, and the camshaft chain wheel II is coaxially and fixedly connected with an exhaust camshaft I and used for controlling the exhaust valve of the cylinder close to the exhaust camshaft II to be opened or closed;

the crankshaft chain wheel, the camshaft chain wheel I and the camshaft chain wheel II are connected in a chain transmission mode through a circle of timing chain I, one end of the timing chain I sequentially strides around the camshaft chain wheel I and the camshaft chain wheel II, and the other end of the timing chain I strides around the crankshaft chain wheel;

the two ends of the crankshaft chain wheel are respectively provided with a chain tooth I and a chain tooth II which are coaxial, and the number of teeth of the chain tooth I is the same as that of the chain tooth II. The sprocket I and the timing chain I are connected in a chain transmission mode; the chain teeth II are connected with one end of a circle of timing chain II in a chain transmission mode, the other end of the timing chain II sequentially strides around a camshaft chain wheel III and a camshaft chain wheel IV in a chain transmission mode, the camshaft chain wheel III is arranged close to the inlet valve of the other cylinder of the engine, and the camshaft chain wheel III is coaxially and fixedly connected with an inlet camshaft II for controlling the inlet valve of the cylinder close to the inlet valve to be opened or closed; the camshaft chain wheel IV is coaxially and fixedly connected with an exhaust camshaft II for controlling the opening or closing of an exhaust valve close to the cylinder.

Because the crankshaft is coaxial with the crankshaft sprocket, when the crankshaft rotates, the crankshaft sprocket as a driving wheel can be driven to drive the camshaft sprocket I, the camshaft sprocket II, the camshaft sprocket III and the camshaft sprocket IV as a driven wheel to rotate in a chain transmission mode, correspondingly, the inlet valve and the exhaust valve of the cylinder bodies on two sides of the engine are opened or closed, finally, the two cylinders are horizontally arranged opposite to the engine for air distribution, the inlet valve and the exhaust valve of the cylinder bodies on two sides are opened or closed at a specified time according to the requirement of the working cycle of the engine, combustible mixed gas or air enters the cylinders on two sides of the engine, and combusted waste gas is exhausted.

As a further improvement of the invention, a timing chain I between a crankshaft chain wheel and a camshaft chain wheel I is connected into a balance shaft chain wheel in a chain transmission mode, the balance shaft chain wheel and a gear I are coaxially and fixedly connected onto the balance shaft I, a timing chain I between the crankshaft chain wheel and the camshaft chain wheel II is connected into another balance shaft chain wheel in a chain transmission mode, the balance shaft chain wheel and the gear II are coaxially and fixedly connected onto the balance shaft II, and the gear I is meshed with the gear II.

The gear I is meshed with the gear II, the balance shaft I transmits the driving force from the crankshaft to the other balance shaft II in a gear meshing mode, so that the two balance shafts are equal in running speed and opposite in rotating direction, more chain wheels are connected into a chain, and the stability of chain transmission can be guaranteed;

and because of the installation height of the balance shaft chain wheel 26 of the balance shaft I and the balance shaft II, the position of the timing chain I cut into or out of the movable guide rail I or the static guide rail I can be adjusted, and the timing chain I can be tensioned by matching with the first tensioning device.

As a further improvement of the invention, the shaft sections of the balance shaft I or the balance shaft II close to the balance shaft chain wheel are respectively provided with an eccentric balance block.

Eccentric balance blocks are respectively assembled on the balance shaft I and the balance shaft II, and the two balance shafts synchronously rotate along with the crankshaft. The resultant force of the inertia force generated by the rotation of the eccentric balance blocks is equal to the first-order reciprocating inertia force generated by the self-running of the engine, and the direction of the resultant force is opposite to that of the first-order reciprocating inertia force generated by the self-running of the engine, so that the first-order reciprocating inertia force generated during running can be balanced, the engine can obtain good balance effect, and the vibration of the engine is reduced.

As a further improvement of the invention, the shaft section of one end of the balance shaft I or the balance shaft II, which is far away from the chain wheel of the balance shaft, is respectively provided with another eccentric balance block, and the shaft section and the balance block which are close to the chain wheel of the balance shaft form an included angle of 180 degrees.

Because the balancing piece rotates along with the balance shaft, the balancing piece which is arranged at an angle of 180 degrees is more beneficial to the self balance of the balancing piece under the influence of the dead weight.

As a further improvement of the invention, the balance weight is in the shape of a sector with the center area removed, the center of the sector is on the axis of the balance shaft, the center of gravity of the sector is on the intersection point of the bisector of the center angle of the sector and the chord line passing through the two ends of the arc line, the center angle and the radius length of the sector are controlled, the center of gravity can be closer to the arc line, and when the balance weight is positioned below, the center of gravity is lower and more stable.

As a further improvement of the invention, a static guide rail III is arranged between a balance shaft chain wheel and a crankshaft chain wheel which are connected with the upper part of the timing chain I in a chain mode, and a section of the timing chain I between the balance shaft chain wheel and the crankshaft chain wheel on the balance shaft I is cut in or cut out along the track of the static guide rail III.

Because a timing chain I between the balance shaft chain wheel on the balance shaft I and the crankshaft chain wheel is cut in or out along the track of the static guide rail III, the chain between the crankshaft chain wheel and the balance shaft chain wheel of the balance shaft I can be prevented from jumping teeth.

In addition, in the technical scheme, the timing chain I is provided with a first tensioning device which comprises a movable guide rail I, the device comprises a static guide rail I and a first tensioner, wherein a movable guide rail I is arranged on a section of timing chain I between a balance shaft chain wheel and a camshaft chain wheel I on a balance shaft I, the timing chain I is cut in or cut out along a track of the movable guide rail I, one end of the movable guide rail I is a fixed end and is arranged close to the camshaft chain wheel I, the other end of the movable guide rail I is a free end and is close to the balance shaft chain wheel on the balance shaft I, a part between the fixed end and the free end of the movable guide rail I downwards protrudes, one section of timing chain I between the balance shaft chain wheel and the camshaft chain wheel I on the balance shaft I is pressed down and tensioned, the first tensioner is arranged on the free end of the movable guide rail I, the lower end of the first tensioner is fixedly connected with the free end of the movable guide rail; the two ends of the static guide rail I are fixed ends, one end of the static guide rail I is installed close to the camshaft chain wheel II, the other end of the static guide rail I is installed close to the balance shaft chain wheel, a cutting timing chain I between the balance shaft chain wheel on the balance shaft II and the camshaft chain wheel IV is cut in or out along the track of the static guide rail I, the part between the two fixed ends of the static guide rail I protrudes upwards, and a cutting timing chain I between the balance shaft chain wheel on the tensioning balance shaft II and the camshaft chain wheel IV is lifted.

Because I free end of first tensioning ware lower extreme rigid coupling movable guide rail can drive I free end of movable guide rail to I stiff end of movable guide rail rotates as the axle, thereby can push down I upper portion chain of timing chain, reaches the effect of tensioning.

In addition, in the above technical solution, the timing chain ii is provided with a second tensioning device, the second tensioning device comprises a movable guide rail ii, a stationary guide rail ii and a second tensioner, the movable guide rail ii is installed between the crankshaft sprocket and the camshaft sprocket IV, and has a fixed end and a free end, the fixed end is installed near the camshaft sprocket IV, the free end is near the crankshaft sprocket, the portion between the fixed end and the free end is in a convex shape to raise and tension a section of the timing chain ii between the crankshaft sprocket and the camshaft sprocket IV, the section of the timing chain ii between the crankshaft sprocket and the camshaft sprocket IV is cut into or cut out along the track of the movable guide rail ii, the free end of the movable guide rail ii is installed with the second tensioner, the second tensioner is installed below the movable guide rail ii, the upper end of the second tensioner is fixedly connected with the free end of the movable guide rail ii, the second tensioner can drive the free end of the movable, the fixed end of the movable guide rail II is used as a shaft to rotate; two ends of the static guide rail II are fixed ends, one end of the static guide rail II is close to the camshaft chain wheel III, the other end of the static guide rail II is close to the crankshaft chain wheel III, the part between the two ends of the static guide rail II is in a downward convex shape, and a section of the timing chain II between the crankshaft chain wheel and the camshaft chain wheel III is cut in or out along the track of the static guide rail II.

The second tensioner can drive the free end of the movable guide rail II to rotate by taking the fixed end of the movable guide rail II as a shaft, so that the lower chain of the timing chain II can be lifted up, and the tensioning effect is achieved.

As a further improvement of the invention, the first and second tensioners are hydraulic tensioners. The hydraulic tensioning can adopt a proportional system, so that the tension of the whole system can be adjusted more conveniently, and the hydraulic tensioning device also adopts a pressure sensor, so that the tension condition can be known timely.

The invention realizes the timing drive of the air distribution mechanism of the engine with two horizontally-opposed cylinders and the accessory system, has compact structure, strengthens the connection relation between the tension device and the transmission system, and ensures that the tension device and the transmission system are more stable when matched with each other.

Drawings

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

fig. 1 is a schematic view of a timing sprocket mechanism in the prior art.

Fig. 2 is a schematic diagram of the overall arrangement of an embodiment of the present invention.

FIG. 3 is a schematic diagram of a crankshaft sprocket configuration in an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a driving part of a balance shaft i in the embodiment of the invention.

Fig. 5 is a schematic structural diagram of a balancing system in an embodiment of the present invention.

Reference numerals: 1. a crankshaft; 2. a crankshaft sprocket; 3. a static guide rail III; 4. a balance shaft I; 5. a gear I; 6. a first tensioner; 7. a movable guide rail I; 8. an air inlet camshaft I; 9. a camshaft sprocket I; 10. a timing chain I; 11. an exhaust camshaft I; 12. a camshaft sprocket II; 13. a static guide rail I; 14. a balance shaft II; 15. a gear II; 16. a second tensioner; 17. a movable guide rail II; 18. an exhaust camshaft II; 19. a camshaft sprocket IV; 20. a timing chain II; 21. an air inlet camshaft II; 22. a camshaft sprocket III; 23. a static guide rail II; 24. a sprocket I; 25. a sprocket II; 26. a balance shaft sprocket; 27. a cylinder body; 28. a cylinder cover; 29. an oil jet; 30. a balance weight.

Detailed Description

For a better understanding of the invention, its improvements over the prior art are addressed by the prior art referenced in the background section in conjunction with the accompanying drawings, before the detailed description of the embodiments of the invention.

Fig. 1 shows a detailed structure of a timing sprocket mechanism disclosed in prior art chinese utility model patent specification CN202718726U, and reference numerals of the original drawings have been modified accordingly for convenience of description.

When the engine designs the variable valve timing, the intake valve of the cylinder is driven to open or close by the camshaft sprocket I9, the exhaust valve of the cylinder is driven to open or close by the camshaft sprocket II12, in order to ensure the synchronous rotation of the camshaft sprocket I9 and the camshaft sprocket II12, an annular timing chain I10 is needed, one end of the timing chain I10 sequentially strides around the camshaft sprocket I9 and the camshaft sprocket II12, the other end strides around the crankshaft sprocket 2, the crankshaft sprocket 2 is coaxially sleeved with the crankshaft 1, when the crankshaft 1 is driven to rotate, the crankshaft sprocket 2 can be driven to rotate, the influence of chain transmission of the timing chain I10 is received, the camshaft sprocket I9 and the camshaft sprocket II12 can synchronously rotate, the camshaft sprocket I9 can drive the intake valve of the cylinder to open or close, and the camshaft sprocket II12 can drive the exhaust valve of the cylinder to open or close.

In the timing chain wheel mechanism shown in fig. 1, a movable guide rail I7 is arranged on a timing chain I10 between a camshaft chain wheel I9 and a crankshaft chain wheel 2, one end of the movable guide rail I7 is a fixed end and is arranged at a position close to the camshaft chain wheel I9, the other end of the movable guide rail I7 is a free end and is close to the crankshaft chain wheel 2 and is controlled by a first tensioner 6, the first tensioner 6 controls the free end of the movable guide rail I7 to tension the timing chain I10 to prevent the timing chain I10 from jumping, and a static guide rail I is arranged on the timing chain I10 between the camshaft chain wheel II12 and the crankshaft chain wheel 2 and ensures the stable chain transmission of the timing chain I10.

With this timing sprocket mechanism, when the crankshaft 1 drives the crankshaft sprocket 2 to rotate, only the camshaft sprocket I9 and the camshaft sprocket II12 at one end can be controlled to rotate, that is, only the intake valve and the exhaust valve of a single cylinder can be controlled to open or close, and the opening or closing of the intake valve and the exhaust valve of two cylinders of a two-cylinder horizontally-opposite engine cannot be realized.

The invention is an improvement aiming at the problem that the opening or closing of the intake valve and the exhaust valve of two horizontally opposite cylinders cannot be realized by using a chain-driven timing chain wheel mechanism in the prior art.

FIG. 2 is a schematic diagram of the overall arrangement of a two cylinder horizontally opposed engine timing system of an embodiment of the present invention. Fig. 3 is a schematic view showing a detailed structure of the crankshaft sprocket shown in fig. 2.

For convenience of description, the terms "left", "right", "up" and "down" used herein are used in the same direction as the left, right, up and down directions of the drawings, but do not limit the structure of the present invention. Further, for the sake of brevity, the tensioner on the upper right side of the timing system is simply referred to as a first tensioner, and the tensioner on the lower left side of the timing system is simply referred to as a second tensioner.

As shown in fig. 2, the crankshaft sprocket 2 is coaxially sleeved on the crankshaft 1 and driven by the crankshaft 1 to rotate, the crankshaft sprocket 2, the camshaft sprocket I9 and the camshaft sprocket II12 are connected in a chain transmission manner, specifically, a timing chain I10 with a closed end to end is adopted, the right end of the timing chain I10 strides around the camshaft sprocket I9 and the camshaft sprocket II12, the camshaft sprocket I9 is above the camshaft sprocket II12, the camshaft sprocket I9 and the camshaft sprocket II12 are connected only in a chain transmission manner, the camshaft chain wheel I9 and the camshaft chain wheel II12 are respectively sleeved with the air inlet camshaft I8 and the air outlet camshaft I11 in a coaxial way without direct contact, with the intake valve and the exhaust valve of control right side cylinder body open or close, the crankshaft sprocket 2 is striden around to timing chain I10 left end, and the crankshaft links 2 as the action wheel, and camshaft sprocket I9 and camshaft sprocket II12 are as follows the driving wheel, action wheel: crankshaft sprocket 2 and driven wheel: the transmission ratio of the camshaft chain wheel I9 or the camshaft chain wheel II12 is that the number of teeth of a driven wheel/the number of teeth of a driving wheel is 2:1, the crankshaft chain wheel 2, the timing chain I10, the camshaft chain wheel I9, the camshaft chain wheel II12, the intake camshaft I8 and the exhaust camshaft I11 jointly form a transmission system I, and an intake valve and an exhaust valve of a right cylinder body are driven to be opened or closed in a chain transmission mode.

As shown in FIG. 3, the two ends of the crankshaft sprocket 2 are respectively provided with a sprocket I24 and a sprocket II25 which are coaxial, and the number of teeth, the modulus and the reference circle diameter of the sprocket I24 and the sprocket II25 are completely the same. The chain teeth I24 are connected into the timing chain I10 and used as driving wheels, and the driven wheels are driven to rotate in a chain transmission mode. Chain tooth II25 is connected with the right end of timing chain II20 as the driving wheel in a chain transmission mode, timing chain II20 is a chain with the head and the tail closed, the left end of timing chain II20 strides around camshaft sprocket III22 and camshaft sprocket IV19 in sequence, camshaft sprocket III22 is located above camshaft sprocket IV19, camshaft sprocket III22 and camshaft sprocket IV19 are respectively and coaxially sleeved with air inlet camshaft II 21 and exhaust camshaft II 18, camshaft sprocket III22 and camshaft sprocket IV19 are not in direct contact and are only connected in a chain transmission mode, when camshaft sprocket III22 and camshaft sprocket IV19 rotate, air inlet camshaft II22 and exhaust camshaft II 18 correspondingly rotate, and therefore opening or closing of an inlet valve and an exhaust valve of a left cylinder body can be controlled. The crankshaft 1, the crankshaft sprocket 2, the camshaft sprocket III22, the camshaft sprocket IV19, the intake camshaft II 21 and the exhaust camshaft II 18 form a transmission system II.

The common parts of the transmission system I and the transmission system II are a crankshaft 1 and a crankshaft chain wheel 2, and the difference is that the transmission system I is connected with a chain tooth I24 of the crankshaft chain wheel 2 in a chain transmission connection mode, and the transmission system II is connected with a chain tooth II25 of the crankshaft chain wheel 2 in a chain transmission connection mode, so that when the crankshaft 1 rotates, the crankshaft chain wheel 2 serving as a driving wheel can be driven to drive a camshaft chain wheel I9, a camshaft chain wheel II12, a camshaft chain wheel III22 and a camshaft chain wheel IV19 serving as driven wheels to rotate in a chain transmission mode, correspondingly, an intake valve and an exhaust valve of a right cylinder body and an intake valve and an exhaust valve of a left cylinder body are opened or closed, finally, the two cylinders are horizontally opposite to the engine air distribution timing, and the intake valve and the exhaust valve of the left cylinder body and the exhaust valve of the right cylinder body are opened, combustible mixture or air is made to enter the left and right cylinders, and burned exhaust gas is discharged.

In the embodiment of the invention, because the crankshaft sprocket 2 as the driving wheel is provided with the structure that the two ends are respectively provided with the coaxial sprocket I24 and the coaxial sprocket II25, compared with the crankshaft sprocket 2 with single sprocket disclosed in the prior art, the valve timing of the left and right cylinder bodies of the engine with two cylinders horizontally opposite can be realized, and in the case of one crankshaft 1, the inlet valve and the exhaust valve of the left and right cylinder bodies can be circularly opened and closed, so that the advantages of chain transmission in a timing system can be fully exerted.

In the embodiment shown in fig. 2, in order to tension the chain and prevent the tooth skipping phenomenon of the chain transmission connection, a first tensioning device consisting of a movable guide rail I7, a static guide rail I13 and a first tensioning device 6 is arranged on a transmission system I of a right cylinder body; and a second tensioning device consisting of a movable guide rail II 17, a static guide rail II 23 and a second tensioner 16 is arranged on the transmission system II of the left cylinder body.

The movable guide rail I7 is installed on a timing chain I10 between a crankshaft chain wheel 2 and a camshaft chain wheel I9, the timing chain I10 is cut into or cut out along a movable guide rail I7 track, one end of the movable guide rail I7 is a fixed end and is installed close to a camshaft chain wheel I9, the other end of the movable guide rail I7 is a free end and is close to the crankshaft chain wheel 2, the part between the fixed end and the free end of the movable guide rail I7 downwards protrudes to press down and tension the upper section of the timing chain I10, a first tensioner 6 is installed on the free end of the movable guide rail I7, the lower end of the first tensioner 6 is fixedly connected with the free end of the movable guide rail I7 and can drive the free end of the movable guide rail I7 to rotate by taking the fixed end of the movable guide rail I7 as a shaft, and therefore the upper chain.

Both ends of static guide rail I13 are all the stiff ends, one end is close to camshaft sprocket II12 and installs, the other end is close to crankshaft sprocket 2 and installs, the part between its both ends is the shape of epirelief, one section that timing chain I10 is located between camshaft sprocket II12 and the crankshaft sprocket 2 cuts into or cuts out along static guide rail I13 track, it is the tensioning to be raised by static guide rail I13, even if the chain on timing chain I10 upper portion is moved guide rail I7 and is pressed down, the chain of lower part is raised by static guide rail I13, nevertheless enough space still remains between I10 upper portion chain of timing chain and the lower part chain, make its upper portion chain and lower part chain can not take place direct contact because of pressing down the tensioning or raising the tensioning, thereby influence the transmission.

The movable guide rail II 17 is arranged between the crankshaft chain wheel 2 and the camshaft chain wheel IV19, and is provided with a fixed end and a free end, the fixed end of the cam shaft chain wheel is arranged close to the cam shaft chain wheel IV19, the free end of the cam shaft chain wheel is close to the crankshaft chain wheel 2, the part between the fixed end and the free end of the cam shaft chain wheel is in a convex shape, so as to lift and tension the lower chain of the timing chain II20, the lower chain of the timing chain II20 is cut into or cut out along the movable guide rail II 17, the free end of the movable guide rail II 17 is provided with a second tensioner 16, the first tensioner 6 and the second tensioner 16 are hydraulic tensioners, the second tensioner 16 is arranged below the movable guide rail II 17, the upper end of the second tensioner 16 is fixedly connected with the free end of the movable guide rail II 17, the second tensioner 16 can drive the free end of the movable guide rail II 17, the fixed end of the movable guide rail II 17 is used as a shaft to rotate, so that the lower chain of the timing chain II20 can be lifted up, and the tensioning effect is achieved.

Two ends of the static guide rail II 23 are fixed ends, one end of the static guide rail II is installed close to the camshaft chain wheel III22, the other end of the static guide rail II is installed close to the crankshaft chain wheel 2, the part between the two ends of the static guide rail II is in a downward convex shape, and an upper chain of the timing chain II20 is cut into or cut out along the track of the static guide rail II 23. Although the upper chain of the timing chain II20 is pressed down by the static guide rail II 23 and the lower chain is lifted up by the driven guide rail II 17, enough space is still left between the upper chain and the lower chain of the timing chain II20, so that the upper chain and the lower chain cannot be in direct contact due to pressing down and tensioning or lifting up and tensioning, and transmission is affected.

In the embodiment of the invention shown in fig. 2, the following modifications can be made to the drive system I and the first tensioning means: a balance shaft I4, a gear I5, a balance shaft II 14 and a gear II 15 which are additionally provided for driving by an auxiliary transmission system I and assisting tensioning of a first tensioning device, wherein in the structure of a driving part of the balance shaft I4 shown in figure 4, the gear I5 and a balance shaft chain wheel 26 are coaxially and fixedly connected to the balance shaft I4, when seen in figure 2, the balance shaft chain wheel 26 is connected to an upper chain of a timing chain I10 and is positioned between a crankshaft chain wheel 2 and a movable guide rail I7, the structure of the driving part of the balance shaft II 14 is the same as that of the driving part of the balance shaft I4, the gear II 15 and another balance shaft chain wheel 26 are coaxially and fixedly connected to the balance shaft II 14, the balance shaft chain wheel 26 on the balance shaft II 14 is connected to a lower chain of the timing chain I10 and is positioned between the crankshaft chain wheel 2 and a static guide rail I13, the transmission ratio of the crankshaft chain wheel 2 to the balance shaft chain wheel 26 is 1:1, the balance shaft I4 transmits the driving force, realize that two balance shaft operating speed are equal, the direction of rotation is opposite, inserts more sprockets in the chain, guarantees chain drive's stability, and the diameter of gear I5, gear II 15 and is greater than balance shaft sprocket 26, and gear I5 is in II 15 tops of gear, and I5 of gear and II 15 meshing transmission of gear. Balance shaft I4, gear I5, balance shaft II 14, gear II 15 and balance shaft sprocket 26 constitute balance shaft drive system. The balance shaft chain wheel 26 can adjust the position of the upper chain or the lower chain of the timing chain I10 cutting into or out of the movable guide rail I7 or the static guide rail I13, and the timing chain I10 is tensioned by the first tensioning device.

The balance shafts I4 and II 14 can also balance the first-order reciprocating inertia force generated during operation, as shown in FIGS. 2 and 4, eccentric balance weights 30 are respectively assembled on the balance shafts I4 and II 14, the balance weights 30 extend along the radial direction of the balance shafts I4 or II 14, the balance weights 30 are preferably in a shape of sector with the circle center area removed, and the balance shafts rotate synchronously with the crankshaft 1. These eccentric weights30The resultant force of the inertia force generated by rotation is equal to the first-order reciprocating inertia force generated by the self-running of the engine, and the directions are opposite, so that the first-order reciprocating inertia force generated during running can be balanced, the engine obtains a good balancing effect, and the vibration of the engine is reduced. When the balance shaft I4 and the balance shaft II 14 are arranged, the balance shaft I4 and the balance shaft II 14 are vertically symmetrical along the horizontal plane where the axis of the crankshaft 1 is located.

In fig. 5, a balance weight 30 is further added to one end of the balance shaft i 4 or the balance shaft ii 14 far from the balance shaft sprocket 26, and the balance weight 30 can be seen as that the balance weight 30 close to the balance shaft sprocket 26 is moved to a shaft section far from the balance shaft sprocket 26, and is formed by rotating 180 degrees, and under the influence of self weight, the balance weights 30 are more beneficial to self balance.

In the embodiment of the invention shown in fig. 2, the following improvements can be made to the balance shaft drive system described above: install quiet guide rail III 3 between crankshaft sprocket 2 and the balance shaft sprocket 26 of balance shaft I4, quiet guide rail III 3 has two stiff ends, and one end is close to crankshaft sprocket 2 and installs, and the other end is close to the balance shaft sprocket 26 installation of balance shaft I4, makes the chain between crankshaft sprocket 2 and the balance shaft sprocket 26 of balance shaft I4 cut into or surely go out along the track of quiet guide rail III 3, prevents that the chain between crankshaft sprocket 2 and the balance shaft sprocket 26 of balance shaft I4 from jumping the tooth.

The invention realizes the timing drive of the air distribution mechanism of the engine with two horizontally-opposed cylinders and the accessory system, has compact structure, strengthens the connection relation between the tension device and the transmission system, and ensures that the tension device and the transmission system are more stable when matched with each other.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several equivalent substitutions or obvious modifications can be made without departing from the spirit of the invention, and all the properties or uses are considered to be within the scope of the invention.