CN2572008Y - Valve operation mechanism for engine - Google Patents

Abstract

A valve operating mechanism includes rocker shafts, a cam follower press-fit onto one end of each rocker shaft, and a rocker arm press-fit onto the other end of the rocker shaft. An abutment surface is formed on the cam follower and the rocker arm, and a reference surface is formed on the engine block so that when the cam follower and the rocker arm are in phase with each other, the abutment surface and the reference surface follow the cam follower and the rocker arm. The directions of rotation of the arms lie against each other. Therefore, the cam follower and the rocker arm can be fixed to the rocker shaft in proper phase, and the proper phase can be confirmed.

Description

engine valve operator

【Technical field】

The utility model relates to a valve control mechanism of an engine, which comprises a cam operatively connected with a crankshaft, a rocker shaft rotatably supported in a bearing seat hole of the engine body, each fixed at one end of each rocker shaft and A cam follower whose top end is in sliding contact with the cam, and a rocker arm fixed to the other end of the rocker shaft and whose top end is connected to a valve installed on the engine body.

【Background technique】

The applicant of the present utility model once proposed such an engine valve operating mechanism (see Japanese Patent Application No. 2000-276459). In this mechanism, a cam with a larger diameter is arranged on one side of the engine body, and a rocker arm and a rocker shaft with a smaller diameter are arranged directly above the engine body. Therefore, the upward protrusion of the valve operating mechanism is restricted, thereby reducing the overall height of the engine, and thereby making the engine compact.

In this valve operating mechanism, in order to properly open and close the valve by the cam, it is required that the phases of the cam follower and the rocker arm around the shaft axis of the rocker arm be adapted to each other.

【Content of invention】

Accordingly, it is an object of the present invention to provide an engine valve operating mechanism and a method of assembling the valve operating mechanism in which the cam follower and rocker arm can be fixed and properly phased on the rocker arm shaft, and Proper mutual phase between cam follower and rocker arm can be confirmed.

In order to achieve the above object, according to the first feature of the utility model, a valve operating mechanism of an engine is provided, which has a cam operatively connected with the crankshaft, a rocker arm rotatably supported in the bearing seat hole of the engine body Shafts, cam followers each fixed at one end of each rocker shaft and whose top end is in sliding contact with the cam, and rocker arms fixed at the other end of the rocker shaft and whose top end is connected to a valve installed on the engine body, wherein , there are abutment surfaces on the cam follower and the rocker arm, and a reference surface on the engine block, so that when the phases of the cam follower and the rocker arm around the axis of the rocker arm shaft are mutually appropriate, the abutment surface and the reference surface They abut against each other along the direction of rotation of the cam follower and the rocker arm.

By this feature, proper phasing of the cam follower and rocker arm about the axis of the rocker shaft is ensured during assembly by abutting the abutment face against the reference face of the engine block. Therefore, the valves are opened and closed synchronously by turning the cams.

According to a second feature of the present invention, there is provided a method of assembling an engine valve operating mechanism having the above first feature, comprising the steps of press fitting one end onto one of a cam follower and a rocker arm Install each rocker arm shaft into the bearing housing hole, put the adjoining surface of one of the cam follower and rocker arm against the corresponding reference surface, and in this state, align the cam follower and rocker arm Press fit the other of the two to the other end of the rocker shaft while pressing the other abutment against the corresponding reference surface.

Through the above-mentioned second feature, the proper phase between the cam follower and the rocker arm can be confirmed at the same time as the cam follower and the rocker arm are connected to the rocker shaft, so that the mechanism has a satisfactory quality and productivity.

The above and other objects, features and advantages of the utility model can be clearly obtained from the following description of the preferred embodiments of the utility model in conjunction with the accompanying drawings.

【Description of drawings】

Fig. 1 is a vertical sectional view of an engine with a valve operating mechanism of the present invention.

Fig. 2 is an exploded view of the main body of Fig. 1 .

Fig. 3 is a sectional view along line 3-3 in Fig. 1 .

Fig. 4 is a sectional view along line 4-4 in Fig. 3 .

Fig. 5 is a sectional view along line 5-5 in Fig. 4 .

Fig. 6 is a sectional view along line 6-6 of Fig. 4 .

Figures 7A and 7B are views corresponding to Figure 5, but showing the assembly process of the valve operating mechanism.

Figures 8A and 8B are views corresponding to Figure 6, but showing the assembly process of the valve operating mechanism.

Figure 9 is a front view of the driven pulley/cam assembly in the valve operating mechanism.

Fig. 10 is a sectional view along line 10-10 in Fig. 9 .

Fig. 11 is a sectional view along line 11-11 in Fig. 10 .

【Detailed ways】

Embodiments of the utility model will be described below in conjunction with the accompanying drawings.

As shown in Figures 1-4 and 6, the engine body 1 of the engine E includes a crankcase 2 with a crank chamber 2a, a cylinder block 3 with a single cylinder hole 3a, and a combustion chamber 5 and an intake air and a combustion chamber leading to the combustion chamber 5. Cylinder head 4 of exhaust port 6,7.

A crankshaft 10 disposed in the crank chamber 2a is supported on laterally opposite side walls of the crank case 2 via bearings 11 and 11' provided on the laterally opposite side walls of the crank case 2.

Fuel tank 12 is connected as a whole with the left side wall of crankcase 2 near the place outside crankcase 2, and one end of crankshaft 10 passes through fuel tank 12 with the mode of sealing oil-tight.

A belt guide 13 of flat section is integrated with the top wall of the fuel tank 12 and extends vertically through the top wall. The lower end of the belt guide 13 extends to the vicinity of the crankshaft 10 located in the oil tank 12 . The upper end of the belt conduit 13 is integrally connected with the cylinder head 4 , thereby sharing the partition wall 14 with the cylinder head 4 . A series of annular sealing flanges 15 are formed at the periphery of the cylinder head 4 and at the upper end of the belt duct 13, from which the partition wall 14 protrudes upward.

An annular sealing groove 16 is provided on the lower end surface of the top cover 8 , and the top cover 8 is connected with the upper end of the cylinder head 4 and corresponds to the sealing flange 15 . A linear sealing groove 17 is provided on the inner surface of the top cover 8 to allow the opposite sides of the annular sealing groove 16 to communicate. The annular seal 18 is installed in the annular seal groove 16 , and the linear seal 19 is integrally formed with the annular seal 18 and installed in the linear seal groove 17 . The top cover 8 is connected to the cylinder head 4 through bolts, so that the sealing flange 15 is in pressure contact with the annular seal 18 , and the partition wall 14 is in pressure contact with the linear seal 19 .

The belt guide 13 and the half top cover 8 form a first valve actuating chamber 21a. The cylinder head 4 and the other half of the top cover 8 form a second valve operating chamber 21b. The valve operating chambers 21 a and 21 b are partitioned from each other by the partition wall 14 .

An intake valve 22i and an exhaust valve 22e for opening and closing the intake port 6 and the exhaust port 7, respectively, are provided in the cylinder head 4 in parallel to the cylinder bore 7a.

The valve operating mechanism 23 for opening and closing the intake valve 22i and the exhaust valve 22e will be described below.

As shown in Figures 1-6, the valve operating mechanism 23 includes a synchronous transmission device 23a and a cam device 23b. 21a extends into the second valve operating chamber 21b.

The synchronous transmission device 23a includes a driving pulley 24 fixed on the crankshaft 13 located in the oil tank 12, a driven pulley 25 rotatably supported on the upper part of the belt guide 13, and a synchronous belt threaded between the driving and driven pulleys 24, 25. Belt 26. Hub 30 and cam 29 are integral with driven pulley 25 to form driven pulley/cam assembly 50 . The cam 29 is provided on the same side of the cylinder head 4 as the driven pulley 25 . The driving and driven pulleys 24 and 25 are toothed so that the driving pulley 24 can drive the driven pulley 25 with a reduction ratio of 1/2 through the belt 26 .

The support wall 27 is integrally formed on the outer side wall of the belt guide 13 and extends upwardly into the annular sealing flange 15 to abut against the inner surface of the top cover 8 or to extend adjacent thereto. The support shaft 39 is rotatably supported on the through hole 28a on the support wall 27 and the bottomed hole 28b on the partition wall 14 through both ends thereof. The hub 30 is rotatably supported at the center of a support shaft 39 . The support shaft 39 is inserted from the through hole 28a into the bottomed hole 28b through the shaft hole 35 of the driven pulley 25 and the cam 29 before being mounted on the top cover 8 . After the support shaft 39 is inserted, when the top cover 8 is connected to the cylinder head 4 and the belt conduit 13, the inner surface of the top cover 8 is opposite to the outer end of the support shaft 39 to prevent the support shaft 39 from slipping out.

A pair of bearing housings 31i and 31e are integrally formed with the cylinder head 4, and protrude from the partition wall 14 toward the second valve operating chamber 21b parallel to the support shaft 39. The cam device 23b includes a cam 29, an intake rocker shaft 33i and an exhaust rocker shaft 33e, an intake cam follower 34i and an exhaust cam follower 34e, an intake rocker arm 35i and an exhaust rocker arm 35e, and an intake cam follower 34i and an exhaust rocker arm 35e. Gas spring 38i and exhaust spring 38e, intake rocker shaft and exhaust rocker shaft are rotatably supported in bearing housing holes 32i and 32e in bearing housings 31i and 31e, respectively, intake cam follower and exhaust Each of the gas cam followers is press-fitted on one end of each rocker shaft 33i and 33e and extends toward the cam 29, the intake and exhaust rocker arms being press-fitted in the second valve operating cavity 21b. The other ends of the intake and exhaust rocker shafts 33i and 33e extend to the intake valve 22i and the exhaust valve 22e, and the intake spring and the exhaust spring are installed on the intake valve 22i and the exhaust valve 22e to facilitate These valves 22i and 22e are biased in the closing direction. The intake cam follower 34i and the exhaust cam follower 34e are arranged such that sliding surfaces 36 , 36 on the upper surface of their top ends come into sliding contact with the lower surface of the cam 29 . The intake rocker arm 35i and the exhaust rocker arm 35e are arranged so that the adjusting bolts 37, 37 threaded on the top thereof abut against the upper ends of the intake valve 22i and the exhaust valve 22e.

The support shaft 39 and the intake and exhaust rocker shafts 33i and 33e are disposed above the annular seal flange 15 of the cylinder head 4 and the upper end of the belt duct 13 . Therefore, when the top cover 8 is removed, the support shaft 39 and the intake and exhaust rocker shafts 33i and 33e can be installed and removed above the sealing flange 15 without being hindered by the sealing flange 15. , so it has good assemblability and easy maintenance.

As shown in FIGS. 5-8, abutment surfaces 40i and 40e are respectively formed at the rear of the intake cam follower 34i and the exhaust cam follower 34e opposite the sliding surfaces 36, 36 and parallel to the rocker shaft 33i. and the axis of 33e. The abutment surfaces 41i and 41e are formed at the rear of the intake rocker arm 35i and the exhaust rocker arm 35e opposite to the protruding portions of the adjustment bolts 37, 37, respectively. In addition, reference surfaces 42i and 42e and reference surfaces 43i and 43e are provided on the cylinder head 4, and when the intake cam follower 34i and the intake rocker arm 35i rotate to the outside and side of the cylinder head, the reference surfaces 42i and 42e Abutment surfaces 40i and 40e face, while reference surfaces 43i and 43e face abutment surfaces 41i and 41e when exhaust cam follower 34e and exhaust rocker arm 35e are rotated outward and sideways of the cylinder head.

If the phases of the intake cam follower 34i and the intake rocker arm 35i about the intake rocker axis 33i are adapted to one another, the abutment surfaces 40i and 41i and the reference surfaces 42i and 43i simultaneously abut one another. If the phases of the exhaust cam follower 34e and the exhaust rocker arm 35e about the exhaust rocker axis 33e are adapted to one another, the abutment surfaces 40e and 41e and the reference surfaces 42e and 43e simultaneously abut one another. All the reference surfaces 42i, 42e, 43i and 43e are arranged at the same height position, so they can work simultaneously.

To install the intake cam follower 34i and the intake rocker arm 35i to the intake rocker shaft 33i, the intake cam follower 34i is first press-fit and fixed to one end of the rocker shafts 33i and 33e, and the The rocker shafts 33i and 33e are inserted into the bearing housing holes 32i and 32e. Then, as shown in FIGS. 7B and 8B , the intake rocker arm 35 is rotated outward and sideways from the cylinder head 4 and brings the abutment surfaces 40i and 40e into abutment with the corresponding reference surfaces 42i and 42e. In this state, if the intake rocker arm 35i is press-fitted and fixed to the other end of the rocker shafts 33i and 33e, and at the same time the abutment faces 41i and 41e are made to abut against the corresponding reference faces 43i and 43e, the The intake cam follower 34i and the intake rocker arm 35i may be properly phased relative to each other about the intake rocker shaft 33I. Of course, in the same manner, the exhaust cam follower 34e and the exhaust rocker arm 35e can form a proper relative phase around the exhaust rocker arm shaft 33e. The same effect can also be obtained in the case of first press-fitting the rocker arms 35i and 35e to the rocker shafts 33i and 33e. After the assembly is completed, the cam followers 34i and 34e and the rocker arms 35i and 35e are turned to the working positions located in the middle of the cylinder head 4, as shown in FIGS. 7A and 8A.

As shown in Figures 4 and 5, auxiliary springs 45i and 45e are provided between the cylinder head 4 and the intake cam follower 34i and between the cylinder head 4 and the exhaust cam follower 34e, respectively, so as to facilitate along the intake spring The direction of action of 38i and exhaust spring 38e pushes intake cam follower 34i and exhaust cam follower 34e. Each of the auxiliary springs 45i and 45e is a torsion spring including a coiled portion 46 mounted on the outer periphery of a corresponding one of the rocker shafts 33i and 33e, and the stationary end 47 is locked to the locking portion 49 of the cylinder head 4 Above, the movable end 48 is connected to a corresponding one of the cam followers 34i and 34e, and biases the cam followers 34i and 34e upwardly.

As shown in FIGS. 9-11 , the cam 29 is composed of sintered alloy integrally formed with a cylindrical hub 30 rotatably supported on a support shaft 39 . In this case, the hub 30 is provided protruding from one end surface of the cam 29, and has a cut surface 30a on the outer peripheral surface of the top end thereof. One end surface of the cam 29 is provided with a groove 51 surrounding the hub 30 and a radial protrusion 52 protruding from the bottom surface of the groove 51 . The shape of the groove 51 is substantially similar to the outer peripheral surface of the cam 29, and therefore, the wall thickness of the cam 29 around the groove 51 is substantially constant.

The driven pulley 25 made of synthetic resin is molded together with the hub 30 and the cam 29 . During this process, the outer peripheral surface and cut surface 30a of the hub 30 are surrounded by the material of the driven pulley, that is, synthetic resin, and the groove 51 of the cam 29 is also filled with synthetic resin. A driven pulley/cam assembly is thus formed.

As shown in FIGS. 1 and 2 , a certain amount of lubricating oil o injected through the lubricating oil injection port 12 a is stored in the oil tank 12 . A pair of flingers 55a and 55b are fixed to the crankshaft 13 in the oil tank 40 by a press fit or the like, and are arranged on opposite sides of the driving pulley 24 in the axial direction. The flingers 56a and 56b radially protrude in opposite directions and are bent in such a way that their top ends are separated from each other in the axial direction. When the crankshaft 13 rotates the oil slingers 56a and 56b, at least one of the oil slingers 56a and 56b stirs and diffuses the lubricating oil o in the oil tank 40, thereby generating oil mist even at any operating position of the engine E. At the same time, the generated oil mist enters the first valve operating chamber 21a to lubricate the synchronous transmission 23a, and circulates to the crank chamber 6a, the second valve operating chamber 21b and the oil tank 12 to lubricate the various components and cams in the crank chamber 2a Device 22b.

The operation of this embodiment will be described below.

During the rotation of the crankshaft 10, the driving pulley 24 rotating therewith drives the driven pulley 25 and the cam 29 through the belt 26, and the cam 29 causes the intake and exhaust cam followers 32i and 32e to oscillate appropriately. This swing is transmitted to the intake and exhaust rocker arms 35i and 35e through the respective rocker shafts 33i and 33e, and causes the intake and exhaust rocker arms 35i and 35e to swing. Accordingly, the intake and exhaust valves 22i and 22e are properly opened and closed by cooperating with the intake and exhaust springs 38i and 38e.

During this process, the cam 29 and the hub 30 are lubricated by the oil mist generated in the oil tank 12 . However, the cam 29 and the hub 30 are made of sintered alloy containing numerous micropores so that lubricating oil can be held in these micropores. Therefore, the portion where the cam 29 and the hub 30 are in sliding contact with the cam followers 34i and 34e and the portion where the cam 29 and the hub 30 rotate and slide on the support shaft 39 can be effectively lubricated, thereby avoiding wear, and thus The life of these parts is improved.

Also, the hub 30 is rotatably supported on a support shaft 39, and the support shaft 39 is also rotatably supported on two opposite side walls of the first valve operating chamber 21a. Therefore, during the rotation of the driven pulley 25 and the cam 29, the support shaft 39 also rotates and is subjected to frictional force, thereby reducing the difference in rotational speed between the hub 30 and the support shaft 39. This reduces wear and improves the life of rotating and sliding parts.

In addition, the driven pulley 25 driven by the driving pulley 24 through the belt 26 is made of synthetic resin, so although its diameter is large, its weight is relatively small, thus reducing the weight of the driven pulley/cam assembly 50, And thereby reduce the weight of the engine E.

Furthermore, since the driven pulley 25 is molded to the cam 29 and the hub 30, the driven pulley/cam assembly 50 can be constructed without the need for other special components, further reducing the weight of the assembly 50.

In addition, when the driven pulley 25 is molded to the cam 29 and the hub 30, the outer peripheral surface and cut surface 30a of the hub 30 are surrounded by the material of the driven pulley 25, that is, synthetic resin, and the groove 51 of the cam 29 is filled with synthetic resin. The resin, therefore, improves the connection force in the rotational direction and the axial direction between the driven pulley 25 and the hub 30 and the cam 29 .

In particular, since the shape of the groove 51 is substantially the same as that of the outer peripheral surface of the cam 29, the coupling force between the driven pulley 25 and the cam 29 in the rotational direction is effectively improved. Moreover, since the wall thickness of the cam 29 around the groove 51 is substantially constant, thermal deformation of the cam 29 during sintering is reduced, thereby improving the accuracy of the cam profile shape.

The base circle portion of the cam 29 is opposed to the intake cam follower 34i and the exhaust cam follower 34e. When the downward thrust acting on the base circle portion is released, when the biasing force of the intake spring 38i and the exhaust spring 38e opens the intake valve 22i and the exhaust valve 22e, the intake valve 22i and the exhaust valve 22e pushes up the rocker arms 35i and 35e, so that one end of each rocker shaft 33i and 33e is pushed up and simultaneously swings around its axis, and a pair of forces act on the rocker shafts 33i and 33e.

When the intake cam follower 34i and the exhaust cam follower 34e are each supported on the base circle portion of the cam 29, and in response to the release of the downward urging force on the cam follower, the intake spring 38i and the exhaust The biasing force of the spring 38e closes the intake valve 22i and the exhaust valve 22e, and then the intake valve 22i and the exhaust valve 22e push the rocker arms 35i and 35e upward and swing the rocker arms 35i and 35e around their axes, Thereby acting on one end of each rocker shaft 33i and 33e, pushing them up and applying a pair of forces to the rocker shafts 33i and 33e.

However, the biasing force of the auxiliary springs 45i and 45e connected to the cam followers 34i and 34e makes the upward thrust force always act on the other end of the rocker shafts 33i and 33e, and this pair of forces is counteracted by the thrust force, therefore, the rocker shaft 33i and 33e are fully pushed against the upper surfaces of the bearing housing holes 32i and 32e, thereby preventing chattering caused by this pair of forces in advance, and preventing abnormal noise and impact wear from occurring in advance.

The larger-diameter cam 29 is provided on the same side of the cylinder head 4 as the driven pulley 25, and only the intake and exhaust rocker arms 35i and 35e and the smaller-diameter intake and exhaust rocker shafts 33i and 33e are directly Set above the cylinder head 4. Therefore, the valve operating mechanism 23 cannot protrude greatly above the cylinder head 4, thereby reducing the overall height of the engine E, and thus making the engine E compact.

During assembly of the cam followers 34i and 34e and the rocker arms 35i and 35e, the cam followers 34i and 34e and the rocker arms 35i and 35e fixed at opposite ends of the rocker shafts 33i and 33e such that they abut against the surfaces 40i and 40e To abut against the reference surfaces 42i, 42e, 43i and 43e of the cylinder head 4, the intake cam follower 34i and the intake rocker arm 35i around the rocker shafts 33i and 33e are properly phased. Therefore, by rotating the cam 29, the intake and exhaust valves 22i and 22e are opened and closed synchronously.

In particular, during assembly, each cam follower 34i and 34e is press fitted to one end of each rocker shaft 33i and 33e, and the rocker shafts 33i and 33e are mounted to the bearings of the bearing housings 31i and 31e. Then, the rocker arms 35i and 35e are press-fitted to the other ends of the rocker shafts 33i and 33e. At the same time, the abutment surfaces 41i and 41e of the rocker arms 35i and 35e are press-fitted onto the corresponding reference surfaces 43i and 43e and abut against the corresponding reference surfaces 43i and 43e. Therefore, while connecting the cam followers 34i and 34e and the rocker arms 35i and 35e to the rocker shafts 33i and 33e, the cam followers 34i and 34e and the rocker arms 35i and 35e can be properly phased, thus Both quality and productivity are satisfactory.

Although the embodiments of the present utility model have been described in detail above, it is obvious that the present utility model is not limited to the above-mentioned specific embodiments. Various variations are also possible.

Claims (1)

1. A valve operating mechanism of an engine, which has a cam that is operatively connected to the crankshaft, a rocker shaft that is rotatably supported in the bearing seat hole of the engine body, and is fixed on one end of each of the rocker shafts and a cam follower whose top end is in sliding contact with the cam, and a rocker arm fixed to the other end of the rocker shaft and whose top end is connected to a valve installed on the engine body, wherein an abutment surface is formed on the cam follower and the rocker arm, and a reference surface is formed on the engine body so that when the cam follower and the When the phases of the rocker arms are appropriate to each other, the abutment surface and the reference surface abut against each other along the rotation direction of the cam follower and the rocker arm.

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