CN100434657C - Four-stroke overhead cam engine - Google Patents

Abstract

The invention relates to a four-stroke overhead cam engine, belonging to the technical field of power devices. Its body is mainly composed of cylinder head, cylinder barrel, upper crankshaft half box and chain chamber, and a combustion chamber is formed on the upper part of the cylinder barrel; the intake valve and exhaust valve are respectively arranged on both sides of the cylinder axis B1-B1; the cam The shaft is arranged in the middle of the intake valve and the exhaust valve, the camshaft is parallel to the crankshaft, and intersects with the cylinder axis B1-B1, and is vertical; the rocker arm shaft is arranged in the middle of the intake valve rocker arm and the exhaust valve rocker arm, The rocker shaft is parallel to the crankshaft. The invention reduces the sealing surface of the engine body, realizes the light weight of the engine, improves the heat dissipation of the cylinder head; reduces the width of the cylinder head, and also reduces the height of the engine; The size of the engine head is conducive to the cooling of the outside of the engine combustion chamber and improves the reliability of the whole machine.

Description

Four-stroke overhead cam engine

technical field

The invention relates to a four-stroke overhead cam engine, belonging to the technical field of power devices.

Background technique

At present, for a general four-stroke overhead cam engine, the cylinder head and the body are respectively cast into a split structure. The cylinder head is installed on the body with bolts, and the camshaft is installed on the cylinder head. The number of parts is large, the number of sealing surfaces is large, and the number of man-hours for processing is increased. Parts such as gaskets must be added to the sealing surface to increase the dependence of the seal, thereby increasing the wall thickness of the cylinder part. In addition, single overhead camshafts are generally used to increase the height of the engine, and double overhead camshafts are used to increase the width of the cylinder head. This kind of structure is unfavorable to the lightweight of the engine and the heat dissipation of the cylinder head. A new overhead cam engine is also proposed in U.S. Patent No. US 5706769, whose intake and exhaust valves and intake and exhaust cam followers are set in a single valve operating cam in the cylinder head. opposite sides of the . The intake and exhaust valves are parallel to each other and perpendicular to the crankshaft. The intake and exhaust cam followers form a two-part structure. One arm of the intake and exhaust cam followers extends inwardly from each other to contact the intake and exhaust valves respectively, and the other arm also extends inwardly from each other to contact the valve operating cam below the center of rotation of the valve operating cam One of the cam surfaces, which arranges the rocker arm on both sides of the camshaft, uses one camshaft and two rocker shafts, thereby increasing the number of parts, and the reciprocating range of the two rocker shafts increases, which directly affects It affects the heat dissipation of the cylinder head, especially the heat dissipation at the contact between the exhaust valve seat and the combustion chamber.

Contents of the invention

The purpose of the present invention is to overcome the above disadvantages, so as to provide a machine body and cylinder head into a whole, reduce the sealing surface, realize the light weight of the engine, improve the heat dissipation of the cylinder head; arrange the camshaft and the rocker arm in two The middle position of the valve does not increase the width of the cylinder head, and also reduces the height of the engine; by reducing the number of parts of the entire valve drive mechanism, the size of the engine head is reduced, which is beneficial to the cooling of the engine combustion chamber and can improve Machine reliability.

Main solution of the present invention is realized like this:

In the present invention, the body, the crankcase cover, and the cylinder head cover are formed by die-casting of aluminum alloy or magnesium alloy; the body is connected with the crankcase cover, and the joint surface of the body and the crankcase cover passes through the crankshaft axis A1-A1 and the cylinder axis B1-B1, The crankshaft is installed on the body machine through bearing support; the piston is installed in the cylinder barrel, the combustion chamber is formed by the piston, the body, and the cylinder barrel, and the piston is connected to the crankshaft through the connecting rod group. The characteristics are:

The body is connected by the cylinder head, the cylinder barrel, the upper crankshaft half case and the chain room to form a whole, and the cylinder head cover is fixed on the cylinder head; the upper part of the body is provided with an intake port and an exhaust port, and the intake port and the exhaust port are respectively located in the cylinder. On both sides of the axis B1-B1; there is a hole in the intake port inclined to the cylinder axis B1-B1, the intake valve guide is installed in the hole, the hole is coaxial with the intake valve seat, and there is a hole in the intake valve guide Intake valve; there is a hole in the exhaust passage inclined to the cylinder axis B1-B1, the exhaust valve guide is installed in the hole, the hole is coaxial with the exhaust valve seat, and the exhaust valve is pierced in the exhaust valve guide;

The upper part of the body is equipped with a camshaft through the shaft, the camshaft is arranged in the middle of the intake valve and the exhaust valve, the camshaft is parallel to the crankshaft, and intersects with the cylinder axis B1-B1, and is vertical; the crankshaft is equipped with a timing gear; on the chain The chamber houses a chain or belt that connects the camshaft, on which the toothing is engraved, to the timing gear;

There is a valve rocker arm seat on the upper part of the body, the rocker arm shaft is installed in the valve rocker arm seat, the rocker arm shaft is arranged in the middle position between the intake valve rocker arm and the exhaust valve rocker arm, the rocker arm shaft is parallel to the crankshaft, Crossing and perpendicular to the cylinder axis B1-B1, it is located on the upper part of the camshaft; the rocker arms of the intake and exhaust valves are crossed on the rocker shaft, and the upper and lower ends of the rocker arms of the intake valve and the upper and lower ends of the rocker arms of the exhaust valve are respectively Located on both sides of the crankshaft axis A1-A1, the rocker arm of the intake valve and the rocker arm of the exhaust valve can swing around the rocker axis;

An integrated cam or an integrated intake cam and exhaust cam are provided on the camshaft;

The rocker arm of the intake valve is divided into two sections, the upper end and the lower end, the upper end is connected to the root of the intake valve, and the lower end is made into a circular arc to contact the cam or exhaust cam;

The rocker arm of the exhaust valve is divided into two sections, the upper end and the lower end, the upper end is connected to the root of the exhaust valve, and the lower end is made into an arc shape to contact the camshaft;

Compared with the prior art, the present invention has the following advantages:

The invention has a simple, compact and reasonable structure; since the engine body and the cylinder head are integrated, the sealing surface is reduced, the weight of the engine is reduced, and the heat dissipation of the cylinder head is improved; the camshaft and the rocker arm are arranged between the two valves The position reduces the width of the cylinder head and the height of the engine; by reducing the number of parts of the entire valve drive mechanism, the size of the engine head is reduced, which is beneficial to the cooling of the outside of the engine combustion chamber and improves the overall performance of the engine. Reliability; the structure can be widely used in gasoline engines, diesel engines, single-cylinder, multi-cylinder, air-cooled, water-cooled and other four-stroke single-cylinder engines.

Description of drawings

Fig. 1 is a longitudinal sectional view of the structure of the present invention (embodiment 1).

Figure 2 is a cross-sectional view of structure A-A of the present invention.

Fig. 3 is a top view of the structure Fig. 2 of the present invention.

Fig. 4 is a B-B cross-sectional view of Fig. 3 of the present invention.

Fig. 5 is an exploded view of the valve operating mechanism of the present invention.

Fig. 6 is a longitudinal sectional view of the structure of the present invention (embodiment 2).

Fig. 7 is a top view of Fig. 6 of the structure of the present invention.

Fig. 8 is a C-C cross-sectional view of Fig. 6 of the present invention.

Detailed ways

Below the present invention will be further described in conjunction with the embodiment in the accompanying drawing:

The present invention mainly consists of body 1, crankcase cover 2, cylinder head cover 3, joint surface 4, bolt 5, crankshaft 6, bearing 7, 8, cylinder barrel 9, piston 10, combustion chamber 11, connecting rod group 12, piston pin 13. Intake channel 14, exhaust channel 15, intake valve seat 16, exhaust valve seat 17, intake pipe 18, exhaust pipe 19, intake valve guide 20, exhaust valve guide 21, hole 22, hole 23 , intake valve 24, exhaust valve 25, intake valve spring 26, exhaust valve spring 27, valve spring seat 28, valve spring seat 29, shaft 30, camshaft 31, timing gear 32, timing chain or belt 33. Valve rocker arm seat 34, rocker arm shaft 35, intake valve rocker arm 36 (upper end 38, lower end 39), exhaust valve rocker arm 37 (upper end 40, lower end 41), valve adjusting screw 42a, valve adjusting nut 43a , valve adjusting screw 42b, valve adjusting nut 43b, engine cylinder head 44, chain chamber 45, upper half crankcase 46, cam 47, spark plug 48, intake cam 49 and exhaust cam 50 etc. composition.

Embodiment 1: (the intake and exhaust valves share one cam)

The invention is a single-cylinder air-cooled overhead cam gasoline engine. The engine main parts body 1, crankcase cover 2 and cylinder head cover 3 are molded by aluminum alloy or magnesium alloy. The body 1 and the crankcase cover 2 are obliquely divided at the joint surface 4 and connected with multiple sets of bolts 5 . The connecting surface 4 of the body 1 and the crankcase cover 2 passes through the crankshaft axis A1-A1 and the cylinder axis B1-B1. The rotation of crankshaft 6 is to pass through bearing 7 and bearing 8 at both ends, bearing 7 is supported on the body machine 1, and bearing 8 is supported on the crankcase cover 2.

The engine body 1 is formed by the cylinder head 44, the upper crankshaft half case 46, the cylinder barrel 9, and the chain chamber 45 by bolts. The cylinder head cover 3 is fixed on the cylinder head 44, and the piston 10 is installed in the cylinder barrel 9. It is formed by a piston 10, a body 1 and a cylinder barrel 9. The piston 10 is connected to the crankshaft 6 through the connecting rod group 12, and the connection between the connecting rod group 12 and the crankshaft 6 is relatively free to rotate. The connection between the piston 10 and the connecting rod group 12 is through a piston pin 13, and can relatively freely swing.

The upper part of the engine body 1 also has an air intake duct 14 and an exhaust duct 15 which are formed by casting in advance, and the intake duct 14 and the exhaust duct 15 are respectively located on both sides of the cylinder axis B1-B1. One end of the intake duct 14 leads to the combustion chamber 11, and an intake valve seat 16 is press-fitted at the junction, and the other end forms a plane outside the body 1, where it is connected with the intake pipe 18. One end of the exhaust passage 15 also leads to the combustion chamber 11, and an exhaust valve seat 17 is press-fitted at the junction, and the other end forms a plane on the other side symmetrical to the cylinder axis B1-B1 of the body 1, where it is connected to the exhaust pipe. 19 connected. A hole 22 is processed obliquely to the cylinder axis B1-B1 in the intake passage 14 to press fit an intake valve guide 20, the hole is coaxial with the intake valve seat 16, and an intake valve is pierced in the intake valve guide 20 24. A valve spring seat 28 is installed on the intake valve 24, and an intake valve spring 26 is installed coaxially with the intake valve 24 between the valve spring seat 28 and the body 1. Therefore, when the intake valve spring 26 is compressed, the intake air Door 24 moves down, breaks away from intake valve seat 16, and the air intake is unobstructed; A hole 23 is processed in the exhaust passage 15 inclined to the cylinder axis B1-B1 to press fit an exhaust valve guide 21, the hole is coaxial with the exhaust valve seat 17, and an exhaust valve is pierced in the exhaust valve guide 21 25. A valve spring seat 29 is installed on the exhaust valve 25, and an exhaust valve spring 27 is installed coaxially with the exhaust valve 25 between the valve spring seat 29 and the body 1, so when the exhaust valve spring 27 is compressed, the exhaust Door 25 moves down, breaks away from exhaust valve seat 17, and exhaust is unobstructed;

A camshaft 31 is also assembled on the upper part of the body 1 through a shaft 30. The camshaft 31 is arranged in the middle of the two valves. The camshaft 31 is parallel to the crankshaft 6 and intersects with the cylinder axis B1-B1, perpendicularly. A cam 47 integrally formed on the camshaft 31 is provided so that the camshaft 31 can freely rotate on the shaft 30 . The rotation of the camshaft 31 is mainly driven by the crankshaft 6 . A timing gear 32 is housed on the crankshaft 6, and the timing gear 32 is press-fitted on the crankshaft 6 and rotates together with the crankshaft; a chain or belt 33 is accommodated in the chain chamber 45, and the timing chain or belt 33 connects it The camshaft 31 engraved with the tooth shape is connected with the timing gear 32; and the number of the tooth shape ensures that the rotational speed ratio of the crankshaft 6 and the camshaft 31 is 2:1. The cam 47 on the camshaft 31 deviates from the intake and exhaust valves 24 and 25, and a protruding valve rocker arm seat 34 is provided on the upper part of the body 1, and the rocker arm shaft 35 is installed in the valve rocker arm seat 34, and the rocker arm shaft 35 is arranged In the middle position of the intake valve rocker arm 36 and the exhaust valve rocker arm 37, the rocker arm shaft 35 is parallel to the crankshaft 6, and passes through and is perpendicular to the cylinder axis B1-B1, and is located on the upper part of the camshaft 31; due to the inclination of the valve, The rocker arm is conveniently arranged in the middle of the two valves; one end of the rocker arm shaft 35 is made to protrude for contacting the cylinder head cover 3 to prevent slippage. The intake valve rocker arm 36 is divided into two sections, an upper end 38 and a lower end 39. The upper end 38 is equipped with a valve adjustment screw 42a and a valve adjustment nut 43a connected to the root of the intake valve 24. The lower end 39 forms an arc and contacts the cam 47; The valve rocker arm 37 is divided into two sections, the upper end 40 and the lower end 41. The upper end 40 is equipped with a valve adjusting screw 42b and the valve adjusting nut 43b is connected with the root of the exhaust valve 25. The lower end 41 forms an arc and contacts the cam 47; The valve rocker arms 36, 37 share a rocker shaft 35 and a cam 47, and the intake and exhaust valve rocker arms 36, 37 are crossed on the rocker shaft 35 so as to be connected to the body 1, so that the intake valve rocker The upper end 38 and the lower end 39 of the arm 36, and the upper end 40 and the lower end 41 of the exhaust valve rocker arm 37 are respectively located on both sides of the crankshaft axis A1-A1, and the intake valve rocker arm 36 and the exhaust valve rocker arm 37 can rotate around the rocker arm. The shaft 35 oscillates.

Its working process:

When the crankshaft 6 rotates, the crankshaft 6 drives the camshaft 31 to rotate at a speed of 1/2 through the timing chain 33, thereby pushing the lower end 39 of the intake valve rocker arm 36 and the exhaust valve rocker arm 37 in contact with the cam 47. lower end 41 . Make intake valve rocker arm 36 upper end 38, the upper end 40 of exhaust valve rocker arm 37 swing, overcome the resistance of intake valve spring 26 and exhaust valve spring 27, open intake valve 24 and exhaust valve 25.

On the other hand, the lower end 39 of the intake valve rocker arm 36 and the lower end 41 of the exhaust valve rocker arm 37 are attached to the cam 47. When the cam 47 continues to rotate, there is no pressure on the intake valve rocker arm 36 and the exhaust valve rocker arm 37. , the intake valve 24 and the exhaust valve 25 are opened by the elastic force of the intake valve spring 26 and the exhaust valve spring 27, and the reset of the intake valve rocker arm 36 and the exhaust valve rocker arm 37 is completed.

Embodiment two: (intake and exhaust valve use a cam respectively)

The engine body 1 is combined to form a whole by the cylinder head 44, the cylinder barrel 9 that accommodates the piston, the chain chamber 45, and the upper crankshaft half case 46. The top of the cylinder barrel 9 on the body forms a combustion chamber 11, and the spark plug 48 is used here for timing. Fire into the combustion chamber.

The upper part of the body 1 also has an air intake channel 14 and an exhaust channel 15 formed by casting in advance, and the air intake channel 14 and the exhaust channel 15 are respectively located on both sides of the cylinder axis B1-B1. One end of the intake duct 14 leads to the combustion chamber 11, and an intake valve seat 16 is press-fitted at the junction, and the other end forms a plane outside the body 1 . One end of the exhaust passage 15 also leads to the combustion chamber 11, and an exhaust valve seat 17 is press-fitted at the junction, and the other end forms a plane on the other side symmetrical to the cylinder axis B1-B1 of the body 1. A hole 22 is processed obliquely to the cylinder axis B1-B1 in the intake passage 14 to press fit an intake valve guide 20, the hole is coaxial with the intake valve seat 16, and an intake valve is pierced in the intake valve guide 20 24. A valve spring seat 28 is installed on the intake valve 24, and an intake valve spring 26 is installed coaxially with the intake valve 24 between the valve spring seat 28 and the body 1. Therefore, when the intake valve spring 26 is compressed, the intake air Door 24 moves down, breaks away from intake valve seat 16, and the air intake is unobstructed; A hole 23 is processed in the exhaust passage 15 inclined to the cylinder axis B1-B1 to press fit an exhaust valve guide 21, the hole is coaxial with the exhaust valve seat 17, and an exhaust valve is pierced in the exhaust valve guide 21 25. A valve spring seat 29 is installed on the exhaust valve 25, and an exhaust valve spring 27 is installed coaxially with the exhaust valve 25 between the valve spring seat 29 and the body 1, so when the exhaust valve spring 27 is compressed, the exhaust Door 25 moves down, breaks away from exhaust valve seat 17, and exhaust is unobstructed;

A camshaft 31 is also assembled on the upper part of the body 1 through a shaft 30. The camshaft 31 is arranged in the middle of the two valves. The camshaft 31 is parallel to the crankshaft 6 and intersects with the cylinder axis B1-B1, perpendicularly. An intake cam 49 and an exhaust cam 50 integrally formed on the camshaft 31 drive the intake valve 24 and the exhaust valve 25 respectively.

There is also a protruding valve rocker arm seat 34 on the upper part of the body 1, which is used to assemble a rocker arm shaft 35. The rocker arm shaft 35 is parallel to the crankshaft 6, and passes through and perpendicular to the cylinder axis B1-B1, and is located on the upper part of the camshaft 30. ; Due to the inclination of the valves, the rocker arm is conveniently arranged in the middle of the two valves. The intake valve rocker arm 36 is divided into two sections, the upper end 38 and the lower end 39. The upper end 38 is equipped with a valve adjustment screw 42a and the valve adjustment nut 43a is connected with the root of the intake valve 24, and the lower end 39 forms an arc and contacts the intake cam 49. The exhaust valve rocker arm 37 is divided into two sections, the upper end 40 and the lower end 41. The upper end 40 is equipped with a valve adjusting screw 42b and the valve adjusting nut 43b is connected with the root of the exhaust valve 25, and the lower end 41 forms an arc shape to match the exhaust cam 50 Contact; the intake and exhaust valve rocker arms 36, 37 share a rocker shaft 35, and the intake and exhaust valve rocker arms 36, 37 pass through the rocker shaft 35 to be connected to the body 1, so that the intake valve rocker arm 36 The upper end 38 and the lower end 39 of the upper end 38 and the lower end 39 of the exhaust valve rocker arm 37 are located on both sides of the crankshaft axis A1-A1 respectively, and the intake valve rocker arm 36 and the exhaust valve rocker arm 37 can rotate around the rocker arm shaft 35 swing.

In this way, when the engine is working, the same camshaft rotates, and the intake and exhaust cams open the intake and exhaust valves accordingly, and when the camshaft continues to rotate, the intake and exhaust valves are closed correspondingly due to the action of the return spring, so as to ensure the four strokes of the engine. work reliably.

Claims (6)

1. A four-stroke overhead cam engine, the body (1) is connected with the crankcase cover (2), the crankshaft (6) is mounted on the body (1) through bearing support; the piston is installed in the cylinder barrel (9) (10), combustion chamber (11) is formed by piston (10), body (1), cylinder barrel (9), and piston (10) connects crankshaft (6) by connecting rod group (12), is characterized in that: a. The body (1) is connected to form a whole by the cylinder head (44), cylinder barrel (9), upper crankshaft half case (46), and chain chamber (45), and the cylinder head cover (3) is fixed on the cylinder head (44) ; B, the upper part of the body (1) is provided with an intake duct (14), an exhaust duct (15), and the intake duct (14) and the exhaust duct (15) are respectively located on both sides of the cylinder axis (B1-B1); A hole (22) is arranged in the intake passage (14) and the cylinder axis (B1-B1) inclined, and the intake valve guide (20) is installed in the hole (22), and the hole (22) is connected with the intake valve seat (16 ) are coaxial, and the intake valve (24) is pierced in the intake valve guide (20); a hole (23) is provided in the exhaust passage (15) at an inclination with the cylinder axis (B1-B1), and the exhaust valve The conduit (21) is installed in the hole (23), the hole (23) is coaxial with the exhaust valve seat (17), and the exhaust valve (25) is worn in the exhaust valve conduit (21); c. A camshaft (31) is installed on the upper part of the body (1) through the shaft (30). The camshaft (31) is arranged between the intake valve (24) and the exhaust valve (25). The camshaft (31) is parallel to Crankshaft (6), and intersects with cylinder axis line (B1-B1), vertical; Timing gear (32) is housed on the crankshaft (6); Hold a chain or belt (33) in chain room (45), timing The chain or belt (33) connects the camshaft (31) with the timing gear (32); d. There is a valve rocker arm seat (34) on the upper part of the body (1), the rocker arm shaft (35) is installed in the valve rocker arm seat (34), and the rocker arm shaft (35) is arranged on the intake valve rocker arm (36 ) and the exhaust valve rocker arm (37), the rocker arm shaft (35) is parallel to the crankshaft (6), passes through and is perpendicular to the cylinder axis (B1-B1), and is located on the upper part of the camshaft (31); The door rocker arm (36) and the exhaust valve rocker arm (37) are crossed on the rocker arm shaft (35), the upper end (38) and the lower end (39) of the intake valve rocker arm (36), and the exhaust valve rocker arm The upper end (40) and the lower end (41) of (37) are respectively positioned at the both sides of the crankshaft axis (A1-A1), and the intake valve rocker arm (36) and the exhaust valve rocker arm (37) can rotate around the rocker arm shaft (35 )swing. 2. The four-stroke overhead cam engine according to claim 1, characterized in that the camshaft (31) is provided with an integrated cam (47) or an integrated intake cam (49) and exhaust Air cam (50). 3. The four-stroke overhead cam engine according to claim 1, characterized in that the upper end (38) of the intake valve rocker arm (36) is connected to the root of the intake valve (24), and the lower end (39) Make arc shape and cam (47) contact. 4. The four-stroke overhead cam engine according to claim 1, characterized in that the upper end (40) of the exhaust valve rocker arm (37) is connected to the root of the exhaust valve (25), and the lower end (41) Make arc shape and cam (47) contact. 5. The four-stroke overhead cam engine according to claim 1 or 2, characterized in that the camshaft (31) is engraved with tooth shapes. 6. The four-stroke overhead cam engine according to claim 1, characterized in that the body (1), crankcase cover (2), and cylinder head cover (3) are respectively die-cast from aluminum alloy or magnesium alloy forming.

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