CN113294239A

CN113294239A - Method for assembling variable compression ratio driving structure

Info

Publication number: CN113294239A
Application number: CN202010113512.4A
Authority: CN
Inventors: 刘涛; 杨乐; 苏旭朝; 张树旻; 渠娜; 尹吉; 刘君宇; 董高峰; 钟德华; 王文远; 刘刚; 谷世宁
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2020-02-24
Filing date: 2020-02-24
Publication date: 2021-08-24
Anticipated expiration: 2040-02-24
Also published as: CN113294239B

Abstract

The invention provides an assembly method of a variable compression ratio driving structure, which drives an eccentric shaft in a variable compression ratio mechanism to rotate and comprises a harmonic reducer unit fixedly arranged on an engine cylinder body and a motor unit fixedly arranged on a rigid wheel in the harmonic reducer unit. The assembling method can realize the assembly of the variable compression ratio driving structure, has simpler assembly, can improve the assembly precision, and is beneficial to the reliable arrangement of the driving structure.

Description

Method for assembling variable compression ratio driving structure

Technical Field

The invention relates to the technical field of engines, in particular to an assembly method of a variable compression ratio driving structure.

Background

In order to reduce the engine displacement and improve the fuel combustion efficiency and the fuel economy, the variable compression ratio technology is developed at the same time, and the compression ratio adjusting mode is more and more diversified along with the continuous development of the variable compression ratio technology. The multi-connecting-rod type variable compression ratio mechanism which adopts the matching of the eccentric shaft and the multi-connecting-rod mechanism so as to realize the transmission of the multi-connecting-rod mechanism when driving the eccentric shaft to rotate and further realize the change of the top dead center of the engine piston has become the key point of research and development of many vehicle enterprises.

In the existing multi-link variable compression ratio mechanism, a matching structure of a motor and a harmonic reducer is used as a driving source, and a driving mode for driving an eccentric shaft to rotate is adopted. At present, the transmission mode between motor and the harmonic reducer ware is mostly belt drive among the current structure, or arranges the motor in the side of engine cylinder body to be connected with the harmonic reducer ware transmission. The existing structural form causes the whole width of the engine to be larger, is not beneficial to carrying of the whole vehicle, and in a motor side structure, a motor mounting space is required to be reserved or a motor mounting bracket is required to be processed during cylinder body processing, so that the cylinder body structure is more complex, and the processing difficulty is higher. In addition, in the conventional variable compression ratio mechanism, the driving structure is complicated to assemble, and the assembly precision is difficult to ensure.

Disclosure of Invention

In view of the above, the present invention is directed to a method for assembling a variable compression ratio driving structure, so that the assembling can be simplified and the assembling accuracy can be improved.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method of assembling a variable compression ratio driving structure for driving an eccentric shaft of a variable compression ratio mechanism to rotate, the variable compression ratio driving structure comprising a harmonic reducer unit fixed to an engine block, and a motor unit fixed to a rigid gear of the harmonic reducer unit, a flexible gear of the harmonic reducer unit being drivingly connected to one end of the eccentric shaft, one end of a rotating shaft of the motor unit being extended outward and drivingly connected to a wave generator of the harmonic reducer, one end of the eccentric shaft connected to the flexible gear having an extended end extended to one side of the rotating shaft, the method comprising the steps of:

a. rotatably mounting one end of the eccentric shaft with the extending end in the rigid wheel through a third bearing;

b. the flexible gear is arranged in the rigid gear to be in transmission fit with the rigid gear, and the flexible gear is sleeved on the extension end and is fixedly connected with the eccentric shaft;

c. the connected rigid wheel, the eccentric shaft and the flexible wheel are installed in the engine cylinder body, and the rigid wheel is pre-fixed on the engine cylinder body;

d. installing a reducer small cover on the engine cylinder body, clamping the rigid wheel between the reducer small cover and the engine cylinder body, and fastening the rigid wheel and the connection between the reducer small cover and the engine cylinder body;

e. rotatably mounting the wave generator on the extending end by a first bearing, and pressing the wave generator into the flexible gear to be in transmission fit with the flexible gear;

f. mounting a timing cover on the engine block to enclose the harmonic reducer unit within the engine block;

g. and the motor unit penetrates through the timing cover cap to be fixed on the rigid wheel, so that the extending end of the motor unit is in transmission connection with the wave generator, the wave generator is rotatably arranged on a shell of the motor unit by a second bearing or the wave generator is in sliding butt joint with the shell, and the sealing between the shell and the timing cover cap is completed along with the penetration of the motor unit in the timing cover cap.

Furthermore, an oil duct communicated with a lubricating oil path in the engine cylinder body is formed in the eccentric shaft, and the oil duct axially penetrates through the end part of the extending end of the eccentric shaft.

Further, a lubricant filter assembly is disposed in the oil passage located at the end of the extending end, and the step a further includes installing the lubricant filter assembly in the oil passage.

Further, in the tip of extension end construct have with the notch that the oil duct link up, lubricating oil filtering component is including locating filter screen in the notch, and set firmly in the notch is interior in order to compress tightly the oil of filter screen is stifled, be equipped with in the oil stifled and run through self and one end with the oilhole of oil duct intercommunication.

Further, along the height direction of the engine cylinder block, the rotation axis of the motor unit is offset below the rotation axis of the harmonic reducer unit.

Furthermore, an inner gear ring is constructed in the wave generator, one end of the rotating shaft, which is in transmission connection with the wave generator, is connected with a gear, the gear is located in the wave generator, and the gear is meshed with part of teeth of the inner gear ring to form meshing connection between the gear and the inner gear ring, an opening of the oil duct at the end part of the extending end is arranged opposite to the gear, and the projection of the opening on the gear is located inside a root circle of the gear.

Furthermore, an upper oil hole penetrating through the engine cylinder body is formed in the engine cylinder body, and the upper oil hole penetrates through the inner portion of the rigid wheel connected with the engine cylinder body so as to spray lubricating oil between the rigid wheel and the flexible wheel.

Furthermore, relative to one side of the flexible gear, which is connected with the eccentric shaft, the other side of the flexible gear is provided with a flexible gear gasket arranged in the flexible gear, and the flexible gear is fixedly connected with the eccentric shaft through a connecting piece which is provided with the flexible gear gasket in a penetrating way and the flexible gear.

Furthermore, a positioning part for pre-positioning the installation of the small speed reducer cover is arranged between the engine cylinder body and the small speed reducer cover.

Furthermore, the positioning part comprises positioning pin holes respectively formed in the engine cylinder body and the small speed reducer cover, and positioning pins with two ends respectively inserted into the two positioning pin holes.

Further, a seal ring is provided on the outer periphery of the case to seal between the case and the timing cover; the first bearing positioned on one side of the wave generator is in interference press fit in the wave generator and is in clearance fit with the extending end; and:

the other side of the wave generator is rotatably installed by the second bearing, and the second bearing is pressed in the shell in an interference fit manner and is in clearance fit with the wave generator;

or the other side of the wave generator is in sliding contact with the shell, and a wear-resistant layer is arranged at the position of the shell in sliding contact with the wave generator.

Furthermore, the other side of the wave generator is in sliding abutting joint with the shell, the first bearings are arranged in parallel, a thrust gasket protruding outwards relative to the shell is arranged on the shell, the wave generator is in sliding abutting joint with the shell through the thrust gasket, and the wear-resistant layer is located on the thrust gasket.

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

the assembling method is based on the constitution of the variable compression ratio driving structure, and the assembling sequence of all the parts in the driving structure is arranged, the eccentric shaft and the rigid wheel are firstly connected, then the flexible wheel is assembled, then the eccentric shaft, the rigid wheel and the flexible wheel are assembled in the engine cylinder body, the installation of the timing cover and the penetrating assembly of the motor unit are carried out, and the sealing between the motor and the timing cover is realized along with the penetrating assembly, so that the whole assembling process is simpler, the assembling precision can be improved through the matching among all the parts, and the reliable arrangement of the driving structure in the engine is facilitated.

In addition, the lubricating effect on the driving structure can be ensured through the arrangement of the oil duct in the eccentric shaft, the radial runout of the eccentric shaft can be reduced through the arrangement of the third bearing so as to protect the flexible gear, the flexible gear can be prevented from being crushed and damaged through the arrangement of the flexible gear gasket, the installation of the small cover of the speed reducer can be facilitated through the arrangement of the positioning part between the small cover of the speed reducer and the engine cylinder body, and the damping belt pulley in the engine can be avoided through the fact that the axis of the motor unit is located under the axis of the speed reducer unit, so that the overall design of the engine is facilitated.

In addition, the present invention can reliably support the wave generator to limit the axial play of the wave generator by rotatably mounting one side of the wave generator on the eccentric shaft and rotatably mounting the other side of the wave generator on the housing of the motor unit or slidably abutting against the housing. And adopt the sealing washer to carry out the sealed between motor element and the timing shroud, its simple structure, it is sealed effectual, easily assembly and with low costs.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural view of a variable compression ratio mechanism according to an embodiment of the present invention;

FIG. 2 is a schematic view of a variable compression ratio drive structure according to the embodiment of the present invention;

FIG. 3 is a schematic illustration of the variable compression ratio drive configuration of FIG. 2 assembled in an engine block;

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a schematic diagram of an offset arrangement of a motor unit according to an embodiment of the present invention;

FIG. 6 is a partial enlarged view of portion A of FIG. 3;

FIG. 7 is a schematic view of a thrust washer according to an embodiment of the present invention;

FIG. 8 is a schematic structural view of a wave generator according to an embodiment of the present invention in another form of support;

FIG. 9 is a schematic view of the sealing of the motor unit and the timing cover according to the embodiment of the present invention;

FIG. 10 is a schematic view of the eccentric shaft preassembly according to the embodiment of the present invention;

FIG. 11 is a schematic view of the assembly of the eccentric shaft and the rigid wheel according to the embodiment of the present invention;

FIG. 12 is a schematic view of an assembly of a flexspline according to an embodiment of the present invention;

FIG. 13 is a schematic view of the assembly of the eccentric shaft, the rigid gear and the flexible gear in the engine block according to the embodiment of the present invention;

FIG. 14 is a schematic view of an assembly of a wave generator according to an embodiment of the present invention;

FIG. 15 is an assembled view of the timing cover according to the embodiment of the present invention;

description of reference numerals:

1-piston, 2-crankshaft, 3-adjusting connecting rod, 4-executing connecting rod, 5-eccentric shaft, 6-driving connecting rod, 7-engine cylinder, 8-rigid wheel, 9-flexible wheel, 10-wave generator, 11-shell, 12-rotating shaft, 13-gear, 14-first bearing, 15-thrust gasket, 16-flexible wheel gasket, 17-third bearing, 18-timing cover cap, 19-oil feeding hole, 20-oil seal, 21-sealing ring, 22-damping belt pulley, 23-plug terminal, 24-filter screen, 25-oil plug, 26-second bearing, 27-reducer small cover and 28-positioning pin;

501-eccentric wheel, 502-oil channel, 503-flange part, 504-extension end, 505-connecting hole, 701-positioning pin hole, 1001-inner gear ring, 1101-groove, 1102-embedded groove, 1103-anti-rotation groove and 1501-anti-rotation block.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

The present embodiment relates to an assembling method of a variable compression ratio driving structure, wherein the variable compression ratio driving structure is generally used as a part of a variable compression ratio mechanism to drive an eccentric shaft in the variable compression ratio mechanism to rotate, so as to adjust the compression ratio of an engine.

In detail, as for the above variable compression ratio mechanism, it is embodied as a multi-link type variable compression ratio mechanism, and an exemplary structure of the mechanism may be as shown in fig. 1, when the variable compression ratio mechanism is embodied as a piston 1 provided in an engine cylinder, a crank assembly and an eccentric shaft assembly rotating on an engine cylinder 7, and an adjusting link 3 rotatably fitted on a crank shaft 2 in the crank assembly, an actuating link 4 hinged between the piston 1 and one end of the adjusting link 3, and a driving link 6 hinged between an eccentric shaft 5 in the eccentric shaft assembly and the other end of the adjusting link 3, and generally, the driving link 6 is embodied as a eccentric 501 hinged on the eccentric shaft 5.

The variable compression ratio drive structure of the present embodiment is also provided in the engine block 7, and it is used to drive the above-described eccentric shaft 5 to rotate. At this time, during the operation of the engine, based on the control of the engine ECU, the eccentric shaft 5 is driven to rotate by the driving structure, and then the eccentric wheel 501 on the eccentric shaft 5 drives the driving connecting rod 6 to swing, the driving connecting rod 6 swings to change the swing supporting position of itself, and therefore the top dead center position of the piston 1 is also made to be higher or lower by the conduction of the adjusting connecting rod 3 and the executing connecting rod 4, so that the adjustment of the compression ratio of the engine can be realized.

Of course, the variable compression ratio drive structure of the present embodiment may be applied to other variable compression ratio mechanisms employing an eccentric shaft structure, other than the variable compression ratio mechanism shown in fig. 1, and the present embodiment is not limited thereto, as long as the variable compression ratio mechanism can apply the drive structure of the present embodiment and can obtain the intended effects.

Next, the variable compression ratio drive structure of the present embodiment will be described first, and in this case, as shown in fig. 2 to 4, the variable compression ratio drive structure integrally includes a harmonic reducer unit (X portion) fixed to the engine block 7, and a motor unit (D portion) fixed to the ring gear 8 in the harmonic reducer unit. Like the conventional harmonic reducer structure, the harmonic reducer unit is still composed of a rigid gear 8, a flexible gear 9 and a wave generator 10, and the working principle of the harmonic reducer unit is consistent with that of the conventional harmonic reducer structure. The motor unit of the embodiment can generally adopt a stepping motor to have better rotation amount control precision. Meanwhile, the motor unit is directly fixed on the harmonic reducer unit, and the size of the whole driving structure can be effectively reduced by the embodiment, so that the structure is compact, and the arrangement in an engine is facilitated.

In the harmonic reducer unit of the present embodiment, the rigid gear 8 is fixed to the engine block 7, the flexible gear 9 is in transmission connection with one end of the eccentric shaft 5, one end of the rotating shaft 12 of the motor unit is extended and in transmission connection with the wave generator 10, and the rotating axis of the motor unit is also offset to one side of the rotating axis of the harmonic reducer unit in the present embodiment, so that the motor unit is eccentrically arranged with respect to the harmonic reducer unit. In addition, in the embodiment, the end of the eccentric shaft 5 connected to the flexible gear 9 also has an extending end 504 extending to the side of the rotating shaft 12, the extending end 504 can be specifically referred to as fig. 10 described below, and a shoulder structure is configured on the extending end 504 to perform the following installation of the first bearing 14, and the shoulder is used for limiting the position of the first bearing 14. In the present embodiment, an oil passage 502 communicating with the lubricating oil passage in the engine cylinder 7 is also formed in the eccentric shaft 5, and the oil passage 502 axially penetrates to the end of the extending end 504 of the eccentric shaft 5.

As a preferred embodiment, the present embodiment is directed to the above-described offset arrangement of the motor unit with respect to the harmonic reducer unit, which may be in the height direction of the engine block 7 such that the rotation axis of the motor unit is offset below the rotation axis of the harmonic reducer unit, and particularly, preferentially, as shown in fig. 4, such that the rotation axis n of the motor unit is located directly below the rotation axis m of the harmonic reducer. At this time, referring to fig. 5, the rotational axis of the motor has a distance difference h from the rotational axis of the harmonic reducer unit above the rotational axis.

In the integral structure of the engine, the damping pulley 22 is generally arranged above the harmonic reducer unit, and the engine damping pulley 22 is a flexible part, so that the belt of the gear train is allowed to generate certain amplitude of bounce in the running process in the design requirement. Therefore, by offsetting the motor unit below, it can provide an avoidance space for the bounce of the damping belt pulley 22 and the belt thereon during operation, thereby avoiding the influence on the normal operation of the engine gear train, and by disposing the rotation axis of the motor unit directly below the rotation axis of the harmonic reducer unit, the avoidance effect is optimal at this time.

In the present embodiment, the ring gear 8 of the harmonic reducer unit is fixed to the engine block 7 by bolts, and at the same time, the housing 11 of the motor unit is also fixed to the ring gear 8 by bolts. At this time, the rigid wheel 8 and the housing 11 of the motor unit are also provided with mounting holes for bolts to pass through, and as shown in fig. 5, a two-dot chain line circle e is a connecting line between the mounting holes on the housing 11, and a two-dot chain line circle f is a connecting line between the mounting holes on the rigid wheel 8. Due to the eccentric arrangement of the motor unit, the two-dot chain line circle e intersects with the two-dot chain line circle f instead of being nested, and the housing 11 is also provided with notches at positions corresponding to the mounting holes on the rigid wheel 8 to avoid the mounting holes of the rigid wheel 8, and the notches are larger as they are closer to the intersection of the two-dot chain line circles.

As shown in fig. 2 and 3 in combination with fig. 5, the present embodiment is directed to a transmission connection between a rotating shaft 12 of a motor unit and a wave generator 10, and specifically, an internal gear 1001 is configured in the wave generator 10, a gear 13 is connected to one end of the rotating shaft 12 in transmission connection with the wave generator 10, the gear 13 is located in the wave generator 10, and the gear 13 is also engaged with a part of teeth of the internal gear 1001 to form a meshing connection therebetween. At this time, the teeth of the ring gear 1001 that mesh with the gear 13 are the bottommost portion thereof, matching the eccentric arrangement of the motor unit.

In the present embodiment, through the arrangement of the oil passage 502 in the eccentric shaft 5, lubricating oil can be supplied between the gear 13 and the ring gear 1001, and between the wave generator 10, the flexible gear 9 and other components in the harmonic reducer unit, so as to achieve effective lubrication of each component. At this time, since the extending end 504 of the eccentric shaft 5 is disposed right opposite to the motor unit, and the lubricant oil inevitably contains fine metal impurities, in order to prevent the lubricant oil ejected from the oil passage 502 from entering the motor unit, so that the metal impurities are connected to the solder points on the motor circuit board, and the motor is short-circuited, the embodiment also particularly makes the opening of the oil passage 502 at the end of the extending end 504 and the gear 13 disposed opposite to each other, and the projection of the opening on the gear 13 is also located inside the root circle of the gear 13.

Through the relative position arrangement between the opening of the oil passage 502 and the gear 13 and the projection of the opening of the oil passage 502 is located in the root circle of the gear 13, as seen from fig. 2 or 3, that is, the gear 13 is arranged higher than the opening of the oil passage 502, so that the lubricating oil ejected from the opening of the oil passage 502 is blocked by the gear 13 and flows down along the gear 13, and the motor can be protected, and at this time, because the gear 13 is meshed with the teeth at the bottom in the ring gear 1001, the meshing surface between the two is also exactly located on the flow path of the lubricating oil, so that sufficient lubrication can be obtained, and the problems of dry grinding or high-temperature damage and the like caused by insufficient lubrication can be avoided. Of course, in order to further ensure that the lubricating oil does not enter the interior of the motor, the present embodiment may also be provided with an oil seal 20 between the rotating shaft 12 and the housing 11 of the motor unit, as shown in fig. 2 or 3, and the oil seal 20 may be directly made of a commercially available component.

In order to prevent the impurities from entering the joint of the gear 13 and the ring gear 1001 and other parts in the harmonic reducer unit, as a preferred embodiment, a lubricating oil filtering assembly for filtering lubricating oil is also arranged at the opening part of the oil passage 502 at the end of the extending end 504.

At this time, as an exemplary structure provided for the above-mentioned lubricating oil filtering assembly, as shown in fig. 6, a notch penetrating the oil passage 502 is formed at the end of the extending end 504 on the eccentric shaft 5, and the lubricating oil filtering assembly specifically includes a strainer 24 disposed in the notch, the strainer 24 is pressed in the notch by an oil plug 25 fixedly disposed in the notch, and an oil hole k penetrating itself and having one end communicating with the oil passage 502 is also disposed in the oil plug 25.

It should be noted that, in this embodiment, since the amount of lubricating oil required between the gear 13 and the ring gear 1001, and the flexspline 9, the wave generator 10 and other related components in the harmonic reducer unit is small in use, the diameter of the oil hole k in the oil plug 25 can be designed to be small, so that the lubricating oil can be restricted to ensure the oil pressure in the eccentric shaft 5. In addition, the oil plug 25 can be press-fitted or screwed into a notch at the end of the eccentric shaft 5, and the oil plug 25 can be made of a simpler cylindrical steel block. In the present embodiment, the oil plug 25 is formed by modifying a socket head cap screw, which flattens the tapered end of the screw and drills an oil hole k therein.

It should be noted that the oil plug 25 used in the present embodiment is configured such that the hexagonal socket hole in the oil plug 25 and the oil hole k in the oil plug 25 are communicated with each other to substantially form a part of the oil hole k, but since the hexagonal socket hole has a larger inner diameter than the oil hole k, the lubricating oil discharged from the oil hole k in actual use flows only through the hexagonal socket hole.

By arranging the oil passage 502 in the eccentric shaft 5 and the gear 13 opposite to the opening of the oil passage 502, the lubricating oil from the eccentric shaft 5 of the present embodiment firstly enters the joint of the gear 13 and the inner gear ring 1001, then enters the meshing position of the flexible gear 9 and the rigid gear 8 through the wave generator 10, and finally flows into the oil pan of the engine through the third bearing 17 at the rear end, which will be mentioned later. The lubrication path can meet the lubrication requirements of the gear 13, the inner gear ring 1001, the wave generator 10, the flexible gear 9, the rigid gear 7 and the third bearing 17.

However, as can be seen from fig. 2 or fig. 3, the above-mentioned lubrication path is mainly located below the horizontal plane of the oil passage 502, and since the flexible gear 9 drives the eccentric shaft 5 to rotate only in a certain angle range, and not in a complete rotation, the lubrication range is always fixed in the rotation range of the flexible gear 9, so that poor lubrication is likely to occur in some of the meshing teeth of the flexible gear 9 and the rigid gear 8. In order to avoid such poor lubrication, in a preferred embodiment, in addition to the oil supply of the oil passage 502, the engine block 7 is also provided with an oil applying hole 19 penetrating through the engine block 7, and the oil applying hole 19 penetrates into the inside of the rigid wheel 8 connected to the engine block 7, so that the circulating lubricating oil at the cylinder head, the tensioner or other mechanisms inside the timing cover 18 can be poured down between the rigid wheel and the flexspline 8 9, thereby ensuring the lubricating effect between the flexspline 9 and the rigid spline 8.

In order to prevent larger metal impurities in the lubricating oil, which are difficult to avoid, from entering the meshing portion between the flexible gear 9 and the rigid gear 8, a lubricating oil filtering structure may be provided in the upper oil hole 19, and the structure may be, for example, a strainer fitted into the upper oil hole 19. Furthermore, the upper oil port 19 is preferably arranged with its axial direction perpendicular to the horizontal direction of the engine, although it may be arranged at an angle to the horizontal plane of the engine other than perpendicular.

In the embodiment, the wave generator 10 is of an elliptical structure, radial force cannot be borne in the movement process, the flexible gear 9 is a thin-wall part, when the wave generator 10 is installed in the flexible gear 9, the shape of the flexible gear 9 changes along with the rotation of the wave generator 10, and the shape of the flexible gear 9 is directly determined by the wave generator 10 when meshing teeth on the flexible gear 9 are meshed with the rigid gear 8. If the axial play of the wave generator 10 is too large, the meshing length between the flexible gear 9 and the rigid gear 8 is affected, the force applied to the teeth is directly affected, and even the teeth breaking phenomenon is caused in severe cases, so that the axial play of the wave generator 10 needs to be limited within an allowable range.

Based on the above, the present embodiment is thus, as an alternative to the installation of the wave generator 10, as shown in fig. 2 and 3, one side of the wave generator 10 is rotatably installed on the extension end 504 of the eccentric shaft 5 by the first bearing 14, and the first bearings 14 are also two arranged side by side, and are in clearance fit with the extension end 504 and in interference fit with the wave generator 10. At the same time, the other side of the wave generator 10 is in sliding contact with the housing 11 of the motor unit, and in order to reduce friction loss, a wear-resistant layer is also provided at a portion of the housing 11 in sliding contact with the wave generator 10.

The two rows of the first bearings 14 are adopted in the embodiment, so that one-point support can be changed into two-point support in the axial direction, the support is firmer, and the running stability of the wave generator 10 after installation can be ensured. As for the sliding abutment between the wave generator 10 and the housing 11, it may be such that the wave generator 10 is in direct abutment with the housing 11 and the wear-resistant layer is provided directly on the housing 11 in the relevant place. However, since the housing 11 of the motor unit is made of an aluminum material for the end cover portion, the housing is poor in high temperature resistance and wear resistance, and is likely to be ablated at high temperature, and the friction loss is also large.

In this embodiment, as a preferable arrangement when the housing 11 and the wave generator 10 are in sliding contact with each other, as shown in fig. 7, specifically, a thrust washer 15 is provided at a portion of the housing 11 in sliding contact with the wave generator 10, the thrust washer 15 protrudes outward relative to the housing 11 so as to be in sliding contact with the wave generator 10, and the above-mentioned wear-resistant layer is also provided on the thrust washer 15.

In this embodiment, as an exemplary structure of the thrust washer 15, the thrust washer 15 is annular, and the housing 11 is provided with an insertion groove 1102 for inserting the thrust washer 15. The thrust washer 15 is mounted on the housing 11 by transition fit with the fit-in groove 1102, and a rotation prevention portion for restricting rotation of the thrust washer 15 is also provided between the fit-in groove 1102 and the thrust washer 15. The anti-rotation part specifically includes an anti-rotation groove 1103 disposed on the inner wall of the embedded groove 1102, and an anti-rotation block 1501 disposed on the thrust washer 15 and capable of being clamped in the anti-rotation groove 1103.

Of course, the thrust washer 15 of the present embodiment may have other conventional configurations in addition to the annular thrust washer 15 and its corresponding arrangement described above. Furthermore, it is also possible for the wear-resistant layer provided to be, for example, a wear-resistant alloy layer and the corresponding thrust washer 15 to be made of a steel material as a backing material, or for the thrust washer 15 to be made of another base material and the wear-resistant layer to be provided as a wear-resistant coating.

In addition to the above-described arrangement of the wave generator 10 with one side rotatably mounted by the first bearing 14 and the other side slidably abutting, it should be noted that, as another possible arrangement of the wave generator 10, it is also possible to have one side of the wave generator 10 rotatably mounted on the extension end 504 of the eccentric shaft 5 by means of the first bearing 14 and the other side of the wave generator 10 rotatably mounted in the housing 11 of the motor unit by means of the second bearing 26, as shown in fig. 8.

At this time, only one first bearing 14 is used, and the first bearing 14 is still in interference fit with the wave generator 10, and is still in clearance fit with the extending end 504 of the eccentric shaft 5, and the second bearing 26 on the other side is in clearance fit with the wave generator 10, and is in interference fit with the housing 11 of the motor unit. The present embodiment, by the above-described manner in which both sides are rotatably mounted via bearings, of course, also enables reliable arrangement of the wave generator 10 to limit the amount of axial play of the wave generator 10.

In addition, in the present embodiment, the arrangement of the two wave generators 10 is adopted, the extending end 504 is only arranged at the end of the eccentric shaft 5, and the extending end 504 forms a supporting end for supporting the wave generator 10, compared with the direct supporting mode in which a supporting structure is assembled on the eccentric shaft 5, and then the indirect supporting mode in which the wave generator 10 is assembled is performed, so that the first-stage assembly error can be reduced, and the coaxiality of the extending end 504 and the excircle of the main journal of the eccentric shaft 5 in the assembling process can be effectively ensured, and the transmission precision and reliability of the wave generator 10 are further improved.

In the present embodiment, as also shown in fig. 10, which will be described later, for the connection between the flexspline 9 and the eccentric shaft 5, a radially outwardly protruding flange portion 503 is also formed at the end of the eccentric shaft 5 having the extension end 504, as in the case of the flange attached to the eccentric shaft 5, so that the flange portion 503 is called, and the extension end 504 is also attached to the flange portion 503 and is integrated with the rest of the eccentric shaft 5.

A plurality of connecting holes 505 are provided in the flange 503, wherein the connecting holes 505 are arranged in a ring shape, the connecting holes 505 can be threaded holes, for example, in general, and the flexible wheel 9 can be fastened to the flange 503 by bolts. At this time, since the flexible gear 9 is a thin-walled member, in order to avoid the flexible gear 9 from being damaged by screwing a bolt, in this embodiment, as a preferred implementation form, a flexible gear pad 16 located in the flexible gear 9 may be disposed on the other side of the flexible gear 9 relative to the side of the flexible gear 9 connected to the eccentric shaft 5, the flexible gear 9 is fixedly connected to the eccentric shaft 5 through a connecting member penetrating through the flexible gear pad 16 and the flexible gear 9, and the connecting member here is generally also the bolt.

Meanwhile, regarding the flexible gear pad 16, as an exemplary structure adopted in the present embodiment, the end faces of the two opposite ends are also different in size, so that the outer peripheral surface of the flexible gear pad 16 is similar to a cone, and when in use, the end face with the smaller cross section of the flexible gear pad 16 is attached to the flexible gear 9, thereby facilitating the installation of the flexible gear pad 16 in the flexible gear 9. It should be noted that, instead of using bolts, it is also possible to replace the bolts with rivets or directly weld the flexspline 9 to the flange portion 503 in this embodiment, and when using the welding method, the flexspline 16 may be omitted.

In this embodiment, from the viewpoint of preventing the flexible gear 9 from being deformed too much in the radial direction to protect the flexible gear, a third bearing 17 is also provided at the end of the eccentric shaft 5 connected to the flexible gear 9, so that the eccentric shaft 5 is rotatably mounted in the rigid gear 8 through the third bearing 17. At this time, the radial support of the eccentric shaft 5 by the third bearing 17 can limit the radial runout generated during the cylinder explosion transmitted by the multi-link mechanism borne by the eccentric shaft 5, thereby preventing the flexspline 9 from generating large radial runout due to the driving of the eccentric shaft 5.

It should be noted that, in addition to the third bearing 17 being attached to the ring gear 8, the third bearing 17 may be attached to the engine block 7 in the present embodiment, as a matter of course, in accordance with the dimensional design of the ring gear 8 of the harmonic reducer unit.

In addition, as shown in fig. 2 and fig. 9, the timing cover 18 covering the harmonic reducer unit is attached to the engine block 7, and the motor unit is attached to the rigid wheel 8 across the timing cover 18, and a seal ring 21 is interposed between the housing 11 of the motor unit and the timing cover 18. As shown in fig. 7, a groove 1101 is provided on the outer peripheral wall of the housing 11 of the motor unit, the sealing rings 21 are installed in the groove 1101, and to improve the sealing effect, the sealing rings 21 may be preferably two side by side.

The present embodiment is configured such that the motor unit is connected to the ring gear 8 through the timing cover 18, and a seal structure that seals the fastening bolt of the ring gear 8, the joint surface of the ring gear 8 and the case 11 within the timing cover 18 is provided between the case 11 and the timing cover 18. Therefore, the timing cover 18, the engine cylinder body 7 and the oil pan therein can form a closed space, and the joint surface and the bolt hole which are contacted with lubricating oil are all subjected to oil leakage risk, so that the joint surface of the motor unit and the harmonic reducer unit and the fastening bolt of the harmonic reducer unit can be sealed in the engine cylinder body 7 by arranging the end cover part of the shell 11 in the motor unit and the whole harmonic reducer unit in the closed space, so that the sealing requirements can be reduced or even eliminated, the number of sealing belts can be effectively reduced, the assembly is simplified, and the cost is reduced.

Lubricating oil directly flows into the oil pan after passing through the mounting hole in the rigid wheel 8 in the lubricating process, and the lubricating oil in the harmonic reducer unit cavity also leaks into the oil pan through the joint surface of the shell 11 and the rigid wheel 8, so that the lubricating oil circulation is completed without leakage.

In the present embodiment, based on the above-described configuration of the driving structure, the specific assembling method includes the following steps.

First, the strainer 24 is fixed in the eccentric shaft 5 by the oil plug 25 as shown in fig. 10, but this step can be omitted if the oil strainer assembly is not provided. Then, as shown in fig. 11, the third bearing 17 is press-fitted into the stepped hole of the rigid wheel 8, and the end of the eccentric shaft 5 having the extended end 504 is rotatably mounted in the rigid wheel 8 by passing through the inner ring of the third bearing 17. Next, as shown in fig. 12, the flexible gear 9 is installed in the rigid gear 8, so that the flexible gear 9 is in transmission fit with the rigid gear 8, and the flexible gear 9 is sleeved on the extension end 504 to be attached to the end face of the flange part 503 on the eccentric shaft 5, and then is fixedly connected to the flange part 503 on the eccentric shaft 5 through the flexible gear spacer 16 by bolts.

Then, the engine block 7 is turned 180 ° so that the bottom surface faces upward, the connected rigid ring 8, eccentric shaft 5, and flexspline 9 are fitted into the engine block 7 as shown in fig. 13, and the rigid ring 8 is preliminarily fixed to the engine block 7 by tightening the connecting bolts of the rigid ring 8. Next, the reduction gear small cover 27 is attached to the engine block 7 so as to sandwich the rigid wheel 8 between the reduction gear small cover 27 and the engine block 7, and the rigid wheel 8 and the connection between the reduction gear small cover 27 and the engine block 7 are fastened so that the rigid wheel 8 is fixed in the engine block 7.

Then, the first bearing 14 is press-fitted into the wave generator 10 with interference, and the extension end 504 of the eccentric shaft 5 is inserted from the inner ring of the first bearing 14, whereby the wave generator 10 is rotatably mounted on the extension end 504 of the eccentric shaft 5 via the first bearing 14, and the wave generator 10 is pressed into the flexible gear 9 to be in driving engagement with the flexible gear 9. At this time, when the wave generator 10 is pressed into the flexible gear 9, the wave generator 10 may be rotated into the flexible gear 9 at a constant rotation speed by using a tool having one end fitted into the wave generator 10 as shown in fig. 14, so as to facilitate the pressing of the wave generator 10.

Next, as shown in fig. 15, the timing cover 18 is mounted on the engine block 7, the timing cover 18 is pre-tightened to cover the harmonic reducer unit in the engine block 7, the motor unit is inserted through the timing cover 18 to connect the housing 11 to the rigid wheel 8, and the housing 11 and the timing cover 18 are tightened again, and at this time, the seal ring 21 is sealed between the housing 11 and the timing cover 18 with the insertion of the housing 11, and the connection terminal 23 in the motor unit is located outside the timing cover 18.

The aforesaid is through the arrangement to each part assembly order among the drive structure, utilize earlier to connect eccentric shaft 5 and rigid wheel 8, assemble flexbile gear 9 again, then assemble eccentric shaft 5, the combination of rigid wheel 8 and flexbile gear 9 in engine cylinder body 7, and carry out the installation of timing shroud 18 and the assembly of wearing to establish of electrical unit again, and along with wearing to establish the sealed between casing 11 and the timing shroud 18 that realizes electrical unit in the lump, it makes the whole assembly process comparatively simple, and also can improve the assembly precision through the cooperation between each part.

The support of the wave generator 10 by the housing 1 is carried out before the installation of the motor unit, depending on the design choice, by means of the thrust washer 15 or the second bearing 26, and the wave generator 10 is brought into contact with the thrust washer 15 as the motor unit is inserted, or the wave generator 10 is inserted into the second bearing 26, it being noted that, if the thrust washer 15 is chosen, the first bearings 14 on the other side are arranged in two side by side arrangement, as described above.

In addition, after the motor unit is inserted into the timing cover 18, the motor unit is also rotated to adjust the angle thereof, so that the axis of the motor unit is positioned right below the axis of the harmonic reducer unit, and the opening of the upper plug-in terminal 23 of the motor unit is horizontally directed to the air intake side relative to the engine block. Therefore, the part of the gear 13 on the motor unit, which is engaged with the internal gear 1001 in the wave generator 10, is located at the lowest position vertically below and on the flow path of the lubricating oil, and the opening of the plug terminal 23 faces the air inlet side, so that the plugging and unplugging of the interface can be facilitated.

In addition, in order to facilitate the installation of the retarder small cover 27 in the engine block 7, the present embodiment may preferably also provide a positioning portion between the engine block 7 and the retarder small cover 27 to preposition the installation of the retarder small cover 27. The positioning portion may be, for example, a positioning pin hole 701 provided in each of the engine block 7 and the reducer small cover 27, and a positioning pin 28 having two ends inserted into the two positioning pin holes 701, or the positioning portion may also adopt other existing conventional positioning structures.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method of assembling a variable compression ratio drive structure, characterized by: the variable compression ratio driving structure drives an eccentric shaft (5) in a variable compression ratio mechanism to rotate and comprises a harmonic reducer unit fixedly arranged on an engine cylinder body (7) and a motor unit fixedly arranged on a rigid wheel (8) in the harmonic reducer unit, wherein a flexible wheel (9) in the harmonic reducer unit is in transmission connection with one end of the eccentric shaft (5), one end of a rotating shaft (12) of the motor unit extends outwards and is in transmission connection with a wave generator (10) in the harmonic reducer, one end, connected with the flexible wheel (9), of the eccentric shaft (5) is provided with an extending end (504) extending towards one side of the rotating shaft (12), and the assembling method comprises the following steps:

a. rotatably mounting one end of the eccentric shaft (5) with the extension end (504) in the rigid wheel (8) through a third bearing (17);

b. the flexible gear (9) is arranged in the rigid gear (8) to be in transmission fit with the rigid gear (8), and the flexible gear (9) is sleeved on the extension end (504) and fixedly connected with the eccentric shaft (5);

c. the connected rigid gear (8), the eccentric shaft (5) and the flexible gear (9) are installed in the engine cylinder body (7), and the rigid gear (8) is pre-fixed on the engine cylinder body (7);

d. mounting a reducer small cover (27) on the engine block (7) to sandwich the rigid wheel (8) between the reducer small cover (27) and the engine block (7) and to fasten the connection between the rigid wheel (8) and the reducer small cover (27) and the engine block (7);

e. rotatably mounting one side of the wave generator (10) on the extension end (504) by a first bearing (14), and pressing the wave generator (10) into the flexible gear (9) to be in transmission fit with the flexible gear (9);

f. mounting a timing cover (18) on the engine block (7) to encase the harmonic reducer unit within the engine block (7);

g. and the motor unit penetrates through the timing cover (18) to be fixed on the rigid wheel (8), so that the extending end of the motor unit is in transmission connection with the wave generator (10), the other side of the wave generator (10) is rotatably arranged on a shell (11) of the motor unit by a second bearing (26) or the wave generator (10) is in sliding butt joint with the shell (11), and the sealing between the shell (11) and the timing cover (18) is completed along with the penetration of the motor unit in the timing cover (18).

2. The assembling method of a variable compression ratio driving structure according to claim 1, characterized in that: an oil channel (502) communicated with a lubricating oil channel in the engine cylinder body (7) is formed in the eccentric shaft (5), and the oil channel (502) axially penetrates to the end of an extending end (504) of the eccentric shaft (5).

3. The assembling method of a variable compression ratio driving structure according to claim 2, characterized in that: a lube oil filter assembly is disposed in the oil passage (502) at the end of the extension end (504), and step a further includes installing the lube oil filter assembly in the oil passage.

4. The assembling method of a variable compression ratio driving structure according to claim 3, characterized in that: the end part of the extending end (504) is provided with a notch communicated with the oil duct (502), the lubricating oil filtering assembly comprises a filter screen (24) arranged in the notch and an oil plug (25) fixedly arranged in the notch and used for compressing the filter screen (24), and an oil hole (k) penetrating through the oil plug (25) and communicating with the oil duct (502) is formed in the oil plug (25).

5. The assembling method of a variable compression ratio driving structure according to claim 2, characterized in that: and the rotating axis of the motor unit is offset below the rotating axis of the harmonic reducer unit along the height direction of the engine cylinder body (7).

6. The assembling method of a variable compression ratio driving structure according to claim 5, characterized in that: an inner gear ring (1001) is constructed in the wave generator (10), one end of the rotating shaft (12) in transmission connection with the wave generator (10) is connected with a gear (13), the gear (13) is located in the wave generator (10), the gear (13) is meshed with part of teeth of the inner gear ring (1001) to form meshing connection between the gear and the inner gear ring, an opening of the oil duct (502) at the end of the extending end (504) is arranged opposite to the gear (13), and the projection of the opening on the gear (13) is located inside a tooth root circle of the gear (13).

7. The assembling method of a variable compression ratio driving structure according to claim 2, characterized in that: an upper oil hole (19) penetrating through the engine cylinder body (7) is formed in the engine cylinder body (7), and the upper oil hole (19) penetrates into the rigid gear (8) connected with the engine cylinder body (7) so as to spray lubricating oil downwards between the rigid gear and the flexible gear (9) (8).

8. The assembling method of a variable compression ratio driving structure according to claim 1, characterized in that: and a positioning part for prepositioning installation of the small speed reducer cover (27) is arranged between the engine cylinder body (7) and the small speed reducer cover (27).

9. The assembling method of a variable compression ratio driving structure according to any one of claims 1 to 8, characterized in that: a seal ring (21) is provided on the outer periphery of the housing (11) to seal between the housing (11) and the timing cover (18); the first bearing (14) positioned at one side of the wave generator (10) is pressed in the wave generator (10) in an interference fit mode and is in clearance fit with the extending end (504); and:

the other side of the wave generator (10) is rotatably installed by the second bearing (26), and the second bearing (26) is press-fitted in the shell (11) in an interference manner and is in clearance fit with the wave generator (10);

or the other side of the wave generator (10) is in sliding contact with the shell (11), and a wear-resistant layer is arranged on the part, in sliding contact with the wave generator (10), of the shell (11).

10. The assembling method of a variable compression ratio driving structure according to claim 9, characterized in that: the other side of the wave generator (10) is in sliding abutting joint with the shell (11), the first bearings are arranged in parallel, a thrust gasket (15) protruding outwards relative to the shell (11) is arranged on the shell (11), the wave generator (10) is in sliding abutting joint with the shell (11) through the thrust gasket (15), and the wear-resistant layer is located on the thrust gasket (15).