engine

Abstract

The application discloses an engine, comprising: a cylinder head; a crankcase; a balance mechanism comprising a first balance shaft and a second balance shaft; the engine further comprises: an oil pump assembly connected with the balance mechanism and the crankcase, and arranged at least partially in a second accommodation space; an oil drain groove arranged at least partially in the second accommodation space and comprising a first channel and a second channel, the oil drain groove is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly; the first channel is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly, and is used for balancing the oil pressure inside the crankcase; the second channel is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly, and is used for forming a channel of lubricating oil. The beneficial effect of the application is that the oil pressure inside the crankcase can be balanced by arranging the oil drain groove between the crankcase and the oil pump assembly, thereby avoiding water and oil seepage of the engine, and further improving the sealing performance of the engine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power systems, in particular to an engine. BACKGROUND

[0002] In the prior art, the oil pump is used to inject the lubricating oil splashed by the balance mechanism back into the crankcase. However, in the process of injecting the lubricating oil back into the crankcase, the speed of injecting the lubricating oil back into the crankcase slows down due to the increase of oil pressure, and when the amount of lubricating oil in the oil pump reaches a certain amount, the problem of water and oil seepage of the engine is easily caused. In the existing design, the oil pump and the inside of the crankcase are connected through punching. However, in the actual process, due to the reason of excessive oil pressure in the inside of the crankcase, the oil pressure balance in the crankcase cannot be achieved through the punching form, and thus the problem of water and oil seepage of the engine is still caused, which cannot guarantee the sealing of the engine. SUMMARY

[0003] In order to solve the problem of water and oil seepage of the engine caused by excessive oil pressure in the inside of the crankcase, the present application provides an engine, which comprises: a cylinder head, the cylinder head forms a first accommodating space; an intake and exhaust mechanism, the intake and exhaust mechanism is at least partially arranged in the first accommodating space, the intake and exhaust mechanism comprises an intake mechanism and an exhaust mechanism, the intake mechanism is used for the intake of the engine, and the exhaust mechanism is used for the exhaust of the engine; a cam mechanism, the cam mechanism is at least partially arranged in the first accommodating space and is used for controlling the intake and exhaust mechanism; a crankcase, the crankcase forms a second accommodating space; a crankshaft connecting rod mechanism, the crankshaft connecting rod mechanism is at least partially arranged in the second accommodating space; a balance mechanism, the balance mechanism is at least partially arranged in the second accommodating space and is connected with the crankshaft connecting rod mechanism, and the balance mechanism comprises a first balance shaft and a second balance shaft; the engine further comprises: an oil pump assembly, the oil pump assembly is connected with the balance mechanism and the crankcase, and the oil pump assembly is at least partially arranged in the second accommodating space; an oil drain groove, the oil drain groove is at least partially arranged in the second accommodating space and comprises a first channel and a second channel, the oil drain groove is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly; the first channel is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly, and is used for balancing the oil pressure in the inside of the crankcase; and the second channel is arranged between the crankcase and the oil pump assembly and communicates the crankcase and the oil pump assembly, and is used for forming a channel of lubricating oil.

[0004] Further, the first channel and the second channel coincide with each other and communicate.

[0005] Further, the first channel and the second channel are independently arranged and do not communicate with each other.

[0006] Further, the first channel and the second channel are arranged substantially in parallel.

[0007] Further, the oil drain groove and the crankcase are integrally formed.

[0008] Further, the oil pump assembly is connected with the first balance shaft, and the first balance shaft is used to drive the oil pump assembly.

[0009] Further, the first balance shaft is provided with a flat square connecting hole, and the oil pump assembly is provided with a connecting piece; the first balance shaft and the oil pump assembly are connected through the flat square connecting hole, and the first balance shaft and the oil pump assembly are further connected through the connecting piece.

[0010] Further, the oil pump assembly comprises an oil pump shaft, the oil pump shaft is provided with a connecting piece at one end, and is used to connect the first balance shaft; and an oil pump body, the oil pump body is rotationally connected with the crankcase, and the oil pump shaft is at least partially arranged in the oil pump body.

[0011] Further, the oil pump body is rotationally connected with the crankcase through a bearing.

[0012] Further, the flat square connecting hole and the connecting piece are connected through a clearance fit.

[0013] Compared with the prior art, the engine provided by the application can realize oil pressure balance in the crankcase by setting the oil drain groove between the crankcase and the oil pump assembly, thereby avoiding water and oil seepage of the engine, and further improving the sealing performance of the engine. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of the three-dimensional structure of the engine of the application.

[0015] Figure 2 is an exploded view of the overall structure of the engine of the application.

[0016] Figure 3 is a schematic diagram of the cross-sectional structure of the engine of the application.

[0017] Figure 4 is a schematic diagram of the partial structure of the engine of the application.

[0018] Figure 5 is a schematic diagram of the half cross-sectional structure of the engine of the application.

[0019] Figure 6 is a schematic diagram of the structure of the cylinder block of the application.

[0020] Figure 7 is a first schematic diagram of the cross-sectional structure of the crankcase of the application.

[0021] Figure 8 is a schematic diagram of the cross-sectional structure of the crankcase of the application. Figure 7 at E-E in the application.

[0022] Figure 9 is a schematic diagram of the cross-sectional structure of the crankcase of the application. Figure 8 at F in the application. DETAILED DESCRIPTION

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions in specific embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0024] like Figures 1 to 3 As shown, an engine 100 includes a housing assembly 200, which includes a cylinder head cover 1, a cylinder head 2, a cylinder block 3, a crankcase 4, and an oil pan 5. Side covers 6 are provided on both sides of the crankcase 4. The cylinder head cover 1 covers and seals the cylinder head 2, retaining lubricating oil inside the engine 100 while isolating dirt and moisture from the outside. The cylinder head 2 and cylinder block 3 form a basically sealed space, which seals the gases and constitutes a combustion space to withstand high-temperature, high-pressure combustion gases. The cylinder block 3 and crankcase 4 are the basic structure of the engine 100. The oil pan 5 seals the crankcase 4 and, after connecting to the crankcase 4, forms an oil reservoir to prevent impurities from entering and to collect and store lubricating oil free on the various friction surfaces of the engine 100.

[0025] like Figures 2 to 5 As shown, the engine 100 also includes a cam mechanism 7, an intake and exhaust mechanism 8, an ignition mechanism 9, a piston mechanism 11, a transmission mechanism 12, a crankshaft connecting rod mechanism 13, and a balancing mechanism 14. The housing assembly 200 forms a receiving space 201, in which the cam mechanism 7, intake and exhaust mechanism 8, ignition mechanism 9, piston mechanism 11, transmission mechanism 12, crankshaft connecting rod mechanism 13, and balancing mechanism 14 are at least partially disposed. In this embodiment, the receiving space 201 includes a first receiving space 2011, a second receiving space 2012, and a third receiving space 2013.

[0026] The cylinder head 2 forms a first accommodating space 2011, in which the cam mechanism 7, intake and exhaust mechanisms 8, and ignition mechanism 9 are at least partially disposed. The cylinder block 3 forms a second accommodating space 2012, in which the piston mechanism 11 is at least partially disposed. The crankcase 4 forms a third accommodating space 2013, in which the transmission mechanism 12, crankshaft connecting rod mechanism 13, and balancing mechanism 14 are at least partially disposed. The crankshaft connecting rod mechanism 13 connects the cam mechanism 7, piston mechanism 11, and balancing mechanism 14. The cam mechanism 7 contacts the intake and exhaust mechanisms 8.

[0027] like Figure 4 and Figure 5As shown, the intake and exhaust mechanism 8 includes an intake mechanism 81 and an exhaust mechanism 82. The ignition mechanism 9 is arranged between the intake mechanism 81 and the exhaust mechanism 82. The crankshaft connecting rod mechanism 13 includes a crankshaft 131 and a connecting rod 132, one end of the connecting rod 132 is connected to the piston mechanism 11, the other end of the connecting rod 132 is connected to the crankshaft 131, and the crankshaft 131 is connected to the balance mechanism 14 through gear meshing. The piston mechanism 11 includes a piston 111 and a piston pin 112, and the piston 111 and the connecting rod 132 are connected through the piston pin 112. In the axial direction of the ignition mechanism 9, the cylinder block 3 is arranged near one end of the ignition mechanism 9, and the cam mechanism 7 is arranged near the other end of the ignition mechanism 9. The cam mechanism 7 includes a camshaft 71 and an axle seat 72, and the camshaft 71 includes a first wheel shaft 711 and a second wheel shaft 712. The cylinder head cover 1 and the cylinder head 2 are connected through the axle seat 72. As shown Figure 2 As shown, the crankshaft 131 is connected to the cam mechanism 7 through the valve drive assembly 15, and the valve drive assembly 15 is arranged in the accommodation space formed by the cylinder head 2, the cylinder block 3 and the crankcase 4. The valve drive assembly 15 includes a timing chain 151, and the crankshaft 131 is connected to the cam mechanism 7 through the timing chain 151. As shown Figures 2 to 4 As shown, the transmission mechanism 12 includes a transmission main shaft 121 and a transmission secondary shaft 122, and the transmission main shaft 121 and the transmission secondary shaft 122 are connected through gear meshing. The crankshaft 131 drives the transmission mechanism 12, and the power is transmitted to the front wheels and / or rear wheels of the vehicle through the transmission mechanism 12, so as to drive the vehicle to run.

[0028] As shown Figure 5 As shown, the space between the ignition mechanism 9 and the cylinder block 3 is the combustion chamber 16. The combustion chamber 16 is arranged as the space between the top of the piston 111 and the bottom surface of the cylinder head 2 after the piston 111 reaches the top dead center. The top dead center is the position where the top of the piston 111 is farthest away from the center of rotation of the crankshaft 131. The top of the piston 111 refers to the end surface of the piston 111 close to the cylinder head 2, and the bottom surface of the cylinder head 2 refers to the surface of the cylinder head 2 close to the top of the piston 111.

[0029] The piston 111 is driven by the crankshaft connecting rod mechanism 13, so that the piston 111 makes linear reciprocating motion in the cylinder block 3.

[0030] The intake mechanism 81 is used to send fresh air or combustible mixture into the combustion chamber 16, the ignition mechanism 9 ignites the fresh air or combustible mixture, the fresh air or combustible mixture burns in the combustion chamber 16, the piston mechanism 11 converts the heat energy after combustion into mechanical energy, and drives the crankshaft 131 to move through the connecting rod 132. The crankshaft 131 drives the cam mechanism 7 to move through the valve drive assembly 15, so as to open and close the intake mechanism 81 and the exhaust mechanism 82. At the same time, the crankshaft 131 drives the transmission mechanism 12, so that the transmission mechanism 12 transmits power to the vehicle. The exhaust mechanism 82 filters the exhaust gas after combustion, so as to discharge the exhaust gas into the atmosphere.

[0031] In the working cycle of the engine 100, the speed of the piston 111 is very high and uneven. At the top dead center and bottom dead center positions, the speed of the piston 111 is zero; at the positions between the top dead center and bottom dead center, the speed of the piston 111 reaches the highest. Since the piston 111 makes repeated high-speed linear motion in the cylinder block 3, great inertial forces are generated on the piston 111, the piston pin 112 and the connecting rod 132. The counterweight arranged on the connecting rod 132 can effectively balance these inertial forces. However, only part of the moving mass of the counterweight on the connecting rod 132 participates in the linear motion, and the other part of the counterweight on the connecting rod 132 participates in the rotational motion. Except at the top dead center and bottom dead center positions, the various inertial forces cannot be completely balanced, resulting in vibration of the engine 100. Among them, the top dead center is the position where the top of the piston 111 is farthest from the center of rotation of the crankshaft 131, and the bottom dead center is the position where the top of the piston 111 is closest to the center of rotation of the crankshaft 131. The top dead center and the bottom dead center are combined into the top and bottom dead centers.

[0032] When the piston 111 moves up and down once, it will cause the engine 100 to vibrate twice, once up and once down, so the vibration frequency of the engine 100 is related to the speed of the engine 100. In vibration theory, multiple harmonic vibrations are often used to describe the vibration of the engine, in which the vibration frequency is the same as the speed of the engine, which is called first-order vibration, the frequency is twice the speed of the engine, which is called second-order vibration, and so on. There are third-order and fourth-order vibrations. However, the higher the vibration frequency, the smaller the amplitude, and the second-order and above can be ignored. Among them, the first-order vibration accounts for more than 70% of the entire vibration and is the main source of vibration.

[0033] In order to eliminate vibration, there are many methods, but the commonly used way on motorcycle engines is to increase the balancing mechanism to solve it. As shown in Figure 7 The balancing mechanism 14 includes a shaft on which an eccentric weight 141 is arranged and which rotates synchronously with the crankshaft 131. The counter-vibration force generated by the eccentric weight 141 makes the engine 100 have good balancing effect and reduces the vibration of the engine 100.

[0034] As an implementation manner, the balancing mechanism 14 cooperates with the crankshaft 131 to realize synchronous rotation of the balancing mechanism 14 and the crankshaft 131. The balancing mechanism 14 includes a first balance shaft 142, a first shaft gear 143, a second balance shaft 144, a second shaft gear 145, and a driving shaft gear 146. The crankcase 4 is provided with a plurality of fixed shaft holes 401 corresponding to each other, and the first balance shaft 142, the second balance shaft 14, the transmission main shaft 121, the transmission secondary shaft 122, and the crankshaft 131 are all arranged in the fixed shaft hole 401, and the first balance shaft 142, the second balance shaft 14, the transmission main shaft 121, the transmission secondary shaft 122, and the crankshaft 131 are arranged in parallel. The first shaft gear 143 is arranged on the first balance shaft 142, the second shaft gear 145 is arranged on the second balance shaft 144, and the driving shaft gear 146 is arranged on the crankshaft 131. The driving shaft gear 146 is engaged with the first shaft gear 143 and the second shaft gear 145, respectively. The balancing mechanism 14 adopts a double-balance-shaft mode, in which the first balance shaft 142 and the second balance shaft 144 are arranged in angular symmetry about the center line of the crankshaft 131, the rotation direction of the first balance shaft 142 relative to the crankshaft 131 is opposite to the rotation direction of the second balance shaft 144 relative to the crankshaft 131, the rotation speed of the first balance shaft 142 is the same as the rotation speed of the crankshaft 131, and the rotation speed of the second balance shaft 144 is the same as the rotation speed of the crankshaft 131, so as to balance the first-order reciprocating inertia force of the engine 100, thereby reducing the vibration of the engine 100, reducing the noise of the engine 100, prolonging the service life of the engine 100, and improving the comfort of the driver and the passenger.

[0035] The first balance shaft 142, the second balance shaft 144, and the crankshaft 131 are parallel to each other, the first shaft gear 143 is arranged at one end of the first balance shaft 142, the second shaft gear 145 is arranged at one end of the second balance shaft 144, and the driving shaft gear 146 is arranged at one end of the crankshaft 131. The first shaft gear 143, the second shaft gear 145, and the driving shaft gear 146 are at least partially distributed in the same plane, realizing the engagement between the first shaft gear 143 and the driving shaft gear 146, and the engagement between the second shaft gear 145 and the driving shaft gear 146, so as to facilitate the transmission of the rotating motion of the crankshaft 131 to the first balance shaft 142 and the second balance shaft 144. Among them, the first shaft gear 143 and the first balance shaft 142 are fixed by the existing fixed connection, the first shaft gear 143 and the first balance shaft 142 are fixed by the existing fixed connection, and the driving shaft gear 146 and the crankshaft 131 are fixed by the existing fixed connection.

[0036] The center distance between the first balance shaft 142 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, the center distance between the second balance shaft 144 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, the center distance between the first balance shaft 142 and the crankshaft 131 is a first center distance H, the center distance between the second balance shaft 144 and the crankshaft 131 is a second center distance G, and the first center distance H and the second center distance G are determined by the envelope line 133 movement track of the connecting rod 132, the strength of the first balance shaft 142 and the second balance shaft 144. Specifically, the first center distance H is set to 73 mm, and the second center distance G is set to 73 mm, so as to realize the lightweight of the engine 100 by reducing the center distance between the first balance shaft 142 and the crankshaft 131 and the center distance between the second balance shaft 144 and the crankshaft 131. Wherein, the first center distance H and the second center distance G refer to the shortest distance between the centers of the two shafts, the first center distance H is the shortest distance between the center of the first balance shaft 142 and the center of the crankshaft 131, and the second center distance G is the shortest distance between the center of the second balance shaft 144 and the center of the crankshaft 131.

[0037] As shown in Figure 6 , the cylinder block 3 extends substantially along a first straight line 500. The engine 100 further comprises a projection plane 900 (as shown in Figure 3 ) perpendicular to the axis of the crankshaft 131, the projection plane 900 being perpendicular to the first straight line 500. The cylinder head 2 comprises a through line 29 (as shown in Figure 5 ) passing through itself. As shown in Figure 7As shown, the crankcase 4 includes a first horizontal plane perpendicular to the through line 29, the first horizontal plane is perpendicular to the projection plane 900, and the axis of the crankshaft 131 is on the first horizontal plane. In the direction of the first straight line 500, the axis of the first balance shaft 142 is projected on the projection plane 900 as a first projection point, the axis of the second balance shaft 144 is projected on the projection plane 900 as a second projection point, the axis of the crankshaft 131 is projected on the projection plane 900 as a third projection point, the first horizontal plane is projected on the projection plane 900 as a fourth projection line, the line connecting the first projection point and the third projection point is a fifth projection line, and the line connecting the second projection point and the third projection point is a sixth projection line. The acute angle formed by the fifth projection line and the fourth projection line is a third included angle δ, and the acute angle formed by the sixth projection line and the fourth projection line is a fourth included angle γ. Specifically, the acute angle formed by the projection of the line connecting the axis of the first balance shaft 142 and the axis of the crankshaft 131 on the projection plane 900 and the projection of the first horizontal plane on the projection plane 900 is the third included angle δ, and the acute angle formed by the projection of the line connecting the axis of the second balance shaft 144 and the axis of the crankshaft 131 on the projection plane 900 and the projection of the first horizontal plane on the projection plane 900 is the fourth included angle γ. The third included angle δ is greater than or equal to 0° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 0° and less than or equal to 20°. Within this range, the overall vibration frequency and amplitude of the engine 100 can be minimized, the overall design of the engine 100 can be made smaller and lighter, thereby making the structure of the engine 100 more compact, improving the space utilization of the engine 100, making the engine 100 run more smoothly, and thereby improving the service life of the engine 100. When the third included angle δ is 0° and the fourth included angle γ is 0°, the first projection point, the second projection point, and the third projection point are substantially on the same straight line, that is, the projection of the axis of the first balance shaft 142 on the projection plane 900, the projection of the axis of the second balance shaft 144 on the projection plane 900, and the projection of the axis of the crankshaft 131 on the projection plane 900 are substantially on the same straight line. Specifically, the third included angle δ is set to 20°, and the fourth included angle γ is set to 20°. At this time, the included angle between the fifth projection line and the sixth projection line is 140°, the first center distance H is the shortest center distance 73 mm, and the second center distance G is the shortest center distance 73 mm. When the third included angle δ and the fourth included angle γ are both 20°, and the first center distance H and the second center distance G are both 73 mm, the structure of the engine 100 is the most compact, thereby realizing the lightweight of the engine 100 and improving the resource utilization rate under the condition of ensuring the normal operation of the engine 100. In this embodiment, when the third included angle δ and the fourth included angle γ both exceed 20°, the first balance shaft 142 and the second balance shaft 144 will collide with the internal structure (such as the connecting rod 132) due to the existence of the connecting rod 132 envelope line 133, thereby affecting the overall operation of the engine 100. The connecting rod 132 envelope line 133 refers to the geometric shape formed by the motion trajectory of the connecting rod 132.

[0038] In the embodiment, the third included angle δ and the fourth included angle γ can be arranged substantially symmetrically about the through line 29, i.e. the angles of the two included angles are substantially the same.

[0039] As an implementation manner, when the first center distance H is greater than or equal to 72 mm and less than or equal to 76 mm and the second center distance G is greater than or equal to 72 mm and less than or equal to 76 mm, the third included angle δ is greater than or equal to 0° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 0° and less than or equal to 20°. Specifically, when the center distance between the first balance shaft 142 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, the included angle formed by the fifth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°, and the included angle formed by the sixth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°. Through the above arrangement, the vibration frequency and amplitude of the engine 100 can be reduced, the overall design of the engine 100 can be made smaller and lighter, the structure of the engine 100 can be made more compact, the lightweight of the engine 100 can be realized, the space utilization of the engine 100 can be improved, the stability of the engine 100 in operation can be better, and the service life of the engine 100 can be improved.

[0040] Specifically, when the first center distance H is greater than or equal to 72 mm and less than or equal to 74 mm and the second center distance G is greater than or equal to 72 mm and less than or equal to 74 mm, the third included angle δ is greater than or equal to 0° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 0° and less than or equal to 20°. In the embodiment, when the center distance between the first balance shaft 142 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 74 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 74 mm, the included angle formed by the fifth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°, and the included angle formed by the sixth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°. Through the above arrangement, the vibration frequency and amplitude of the engine 100 can be reduced, the overall design of the engine 100 can be made smaller and lighter, the structure of the engine 100 can be made more compact, the lightweight of the engine 100 can be realized, the space utilization of the engine 100 can be improved, the stability of the engine 100 in operation can be better, and the service life of the engine 100 can be improved.

[0041] Specifically, when the first center distance H is greater than or equal to 72 mm and less than or equal to 74 mm and the second center distance G is greater than or equal to 72 mm and less than or equal to 74 mm, the third included angle δ is greater than or equal to 10° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 10° and less than or equal to 20°. In the embodiment, when the center distance between the first balance shaft 142 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 74 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 74 mm, the included angle between the fifth projection line and the fourth projection line is greater than or equal to 10° and less than or equal to 20°, and the included angle between the sixth projection line and the fourth projection line is greater than or equal to 10° and less than or equal to 20°. Through the above setting, the vibration frequency and amplitude of the engine 100 can be reduced, the overall design of the engine 100 can be made smaller and lighter, the structure of the engine 100 can be made more compact, the weight of the engine 100 can be reduced, the space utilization of the engine 100 can be improved, the engine 100 can run more smoothly, and the service life of the engine 100 can be improved.

[0042] It can be understood that when the first center distance H is greater than or equal to 72 mm and less than or equal to 76 mm and the second center distance G is greater than or equal to 72 mm and less than or equal to 76 mm, the third included angle δ is greater than or equal to 10° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 10° and less than or equal to 20°. Specifically, when the center distance between the first balance shaft 142 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is greater than or equal to 72 mm and less than or equal to 76 mm, the included angle between the fifth projection line and the fourth projection line is greater than or equal to 10° and less than or equal to 20°, and the included angle between the sixth projection line and the fourth projection line is greater than or equal to 10° and less than or equal to 20.

[0043] Specifically, when the first center distance H is 73 mm and the second center distance G is 73 mm, the third included angle δ is greater than or equal to 0° and less than or equal to 20°, and the fourth included angle γ is greater than or equal to 0° and less than or equal to 20°. In the embodiment, when the center distance between the first balance shaft 142 and the crankshaft 131 is 73 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is 73 mm, the included angle between the fifth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°, and the included angle between the sixth projection line and the fourth projection line is greater than or equal to 0° and less than or equal to 20°. Through the above setting, the vibration frequency and amplitude of the engine 100 can be reduced, the overall design of the engine 100 can be made smaller and lighter, the structure of the engine 100 can be made more compact, the weight of the engine 100 can be reduced, the space utilization of the engine 100 can be improved, the engine 100 can run more smoothly, and the service life of the engine 100 can be improved.

[0044] Specifically, when the first center distance H is 73 mm and the second center distance G is 73 mm, the third included angle δ is 20°, and the fourth included angle γ is 20°. In the present embodiment, when the center distance between the first balance shaft 142 and the crankshaft 131 is 73 mm, and the center distance between the second balance shaft 144 and the crankshaft 131 is 73 mm, the included angle between the fifth projection line and the fourth projection line is 20°, and the included angle between the sixth projection line and the fourth projection line is 20°. Through the above arrangement, the overall vibration frequency and amplitude of the engine 100 can be minimized, the overall design of the engine 100 can be made smaller and lighter, thereby making the structure of the engine 100 more compact, achieving the lightweight of the engine 100, improving the space utilization of the engine 100, making the engine 100 run more smoothly, and further improving the service life of the engine 100.

[0045] In addition, when the crankshaft 131 rotates, the inertial mass of the piston 111 and the connecting rod 132 causes the crankshaft 131 to lose balance and generates a large unbalanced force. In order to eliminate this unbalanced force, a balance block 1311 needs to be installed on the crankshaft 131, and the mass, shape and installation position of the balance block 1311 need to be reasonably designed to overcome the centrifugal force generated during the rotation of the crankshaft 131. The eccentric weight 141 is provided on the balance shaft, and the reverse vibration force generated by the eccentric weight 141 can make the engine 100 obtain good balance effect, thereby reducing the vibration of the engine 100.

[0046] As Figure 8 and Figure 9As shown, as an implementation manner, the crankcase 4 is further provided with an oil pump assembly 17, the oil pump assembly 17 is connected to the balance mechanism 14, the balance mechanism 14 includes a first balance shaft 142, a first shaft gear 143, a second balance shaft 144, a second shaft gear 145 and a driving shaft gear 146. The first shaft gear 143 is arranged on the first balance shaft 142, the second shaft gear 145 is arranged on the second balance shaft 144, the driving shaft gear 146 is arranged on the crankshaft 131, and the driving shaft gear 146 is engaged with the first shaft gear 143 and the second shaft gear 145 respectively. The first balance shaft 142, the second balance shaft 144 and the crankshaft 131 are parallel to each other, the first shaft gear 143 is arranged at a first end 1421 of the first balance shaft 142, the second shaft gear 145 is arranged at one end of the second balance shaft 144, and the driving shaft gear 146 is arranged at one end of the crankshaft 131; the oil pump assembly 17 is connected to a second end 1422 of the first balance shaft 142, the crankcase 4 is provided with a balance shaft bushing 147 near the second end 1422, the balance shaft bushing 147 is arranged in the fixed shaft hole 401, and the second end 1422 is arranged in the balance shaft bushing 147. Specifically, a flat square connecting hole 1423 is arranged on the end face of the second end 1422, a connecting piece 171 is arranged on the end face of the oil pump assembly 17 close to the second end 1422, the flat square connecting hole 1423 and the connecting piece 171 are connected through clearance fit, so as to realize the connection between the oil pump assembly 17 and the first balance shaft 142, and make the first balance shaft 142 drive the oil pump assembly 17.

[0047] In the embodiment, the oil pump assembly 17 is used to inject the lubricating oil splashed by the balancing mechanism 14 back into the crankcase 4. However, in the process of injecting the lubricating oil back into the crankcase 4, the speed of the lubricating oil injection into the crankcase 4 slows down due to the increase of the oil pressure, and when the lubricating oil in the oil pump assembly 17 reaches a certain amount, the water seepage and oil seepage problem of the engine 100 is prone to occur. In the original design, the oil pump assembly and the inside of the crankcase are connected through punching. However, in the actual process, due to the excessive oil pressure in the crankcase, the oil pressure balance in the crankcase cannot be achieved through the punching form, and thus the water seepage and oil seepage problem of the engine still occurs, which cannot guarantee the sealing of the engine. In order to prevent the oil pump assembly 17 from causing poor sealing due to excessive oil pressure, the present application provides a drain groove 18 on the crankcase 4. The drain groove 18 can be integrally formed with the crankcase 4 by casting or other methods, which is convenient for processing and improves production efficiency. Specifically, when the lubricating oil splashed by the balancing mechanism 14 enters the oil pump assembly 17, the oil pump assembly 17 injects the lubricating oil into the drain groove 18. Since the drain groove 18 has a certain gap, that is, the drain groove 18 is a drain channel, the lubricating oil will be in one part of the space in the drain groove 18. At this time, when the oil pressure increases, the excessive oil pressure will enter the other part of the space in the drain groove 18, which will not affect the lubricating oil transported to the inside of the crankcase 4 through the drain groove 18, thereby achieving the oil pressure balance in the crankcase 4 and effectively solving the water seepage and oil seepage problem caused by the excessive oil pressure in the crankcase 4.

[0048] As shown in Figure 8 and Figure 9 , specifically, the drain groove 18 includes a first channel 181 and a second channel 182. As an implementation manner, the first channel 181 and the second channel 182 can overlap and communicate with each other. The first channel 181 is the part of the space where the oil pressure enters, and the second channel 182 is the other part of the space where the lubricating oil enters. When the lubricating oil splashed by the balancing mechanism 14 enters the oil pump assembly 17, the oil pump assembly 17 injects the lubricating oil into the drain groove 18. Since the drain groove 18 has a certain gap, that is, the drain groove 18 is a drain channel, the lubricating oil will be in the second channel 182. At this time, when the oil pressure increases, the excessive oil pressure will enter the first channel 181, thereby not affecting the lubricating oil transported to the inside of the crankcase 4 through the drain groove 18, and further achieving the oil pressure balance in the crankcase 4 and effectively solving the water seepage and oil seepage problem caused by the excessive oil pressure in the crankcase 4. It can be understood that the first channel 181 is used to balance the oil pressure in the crankcase 4, and effectively solves the water seepage and oil seepage problem caused by the excessive oil pressure in the crankcase 4. The second channel 182 is used to form a channel for the lubricating oil, so that the lubricating oil can be transported from the oil pump assembly 17 to the crankcase 4 through the drain groove 18. In addition, the first channel 181 and the second channel 182 overlap and communicate with each other, which can facilitate the integration of the drain groove 18 with the crankcase 4, facilitate the processing of the drain groove 18, and improve the production efficiency.

[0049] As an implementation manner, the first channel 181 and the second channel 182 can be independently arranged and not communicated with each other. The first channel 181 is a part of space into which oil pressure enters, and the second channel 182 is another part of space into which lubricating oil enters. When the lubricating oil splashed by the balance mechanism 14 enters the oil pump assembly 17, the oil pump assembly 17 injects the lubricating oil into the oil drain groove 18. Since the oil drain groove 18 has a certain gap, that is, the oil drain groove 18 is an oil drain channel, the lubricating oil will be in the second channel 182. At this time, when the oil pressure increases, the excessive oil pressure will enter the first channel 181, so as not to affect the delivery of the lubricating oil to the inside of the crankcase 4 through the oil drain groove 18, thereby realizing the balance of the oil pressure in the crankcase 4 and effectively solving the problem of water and oil seepage caused by excessive pressure of the crankcase 4. It can be understood that the first channel 181 is used to balance the oil pressure in the crankcase 4 and effectively solve the problem of water and oil seepage caused by excessive pressure of the crankcase 4. The second channel 182 is used to form a channel for the lubricating oil, so that the lubricating oil can be delivered from the oil pump assembly 17 to the crankcase 4 through the oil drain groove 18. In addition, the first channel 181 and the second channel 182 can be independently arranged and not communicated with each other, and can be integrally formed with the oil drain groove 18 and the crankcase 4, facilitating the processing of the oil drain groove 18 and improving the production efficiency.

[0050] As an implementation manner, the oil drain groove 18 is at least partially arranged in the third accommodation space 2013. The oil drain groove 18 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. Specifically, the first channel 181 is at least partially arranged in the third accommodation space 2013. The first channel 181 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. The second channel 182 is at least partially arranged in the third accommodation space 2013. The second channel 182 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. The first channel 181 and the second channel 182 are arranged in parallel. Through the above arrangement, the balance of the oil pressure in the crankcase 4 can be realized, and in the case of excessive oil pressure, the lubricating oil can be smoothly delivered to the crankcase 4, thereby effectively solving the problem of water and oil seepage caused by excessive pressure of the crankcase 4.

[0051] As an implementation manner, the oil drain groove 18 is at least partially arranged in the third accommodation space 2013. The oil drain groove 18 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. Specifically, the first channel 181 is at least partially arranged in the third accommodation space 2013. The first channel 181 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. The second channel 182 is at least partially arranged in the third accommodation space 2013. The second channel 182 is arranged between the crankcase 4 and the oil pump assembly 17 and communicates the crankcase 4 and the oil pump assembly 17. The first channel 181 and the second channel 182 are arranged in parallel. Through the above arrangement, the balance of the oil pressure in the crankcase 4 can be realized, and in the case of excessive oil pressure, the lubricating oil can be smoothly delivered to the crankcase 4, thereby effectively solving the problem of water and oil seepage caused by excessive pressure of the crankcase 4. Figure 9As shown, in the embodiment, the oil pump assembly 17 sequentially comprises an oil pump shaft 172, an oil pump body 173 and an oil pump cover 174, and the oil pump shaft 172, the oil pump body 173 and the oil pump cover 174 are fixedly connected in sequence by a bolt or other fixing mode. The oil pump body 173 forms an oil pump body 173 containing space, the oil pump shaft 172 is at least partially disposed in the oil pump body 173 containing space, the oil pump cover 174 forms an oil pump cover 174 containing space, and the oil pump impeller 175 is at least partially disposed in the oil pump cover 174 containing space. One end of the oil pump shaft 172 is provided with a connecting piece 171 for connecting the oil pump shaft 172 with the first balance shaft 142, so that the first balance shaft 142 drives the oil pump assembly 17. The other end of the oil pump shaft 172 is provided with the oil pump impeller 175, and the oil pump shaft 172 and the oil pump impeller 175 are connected by screw threads. The oil pump shaft 172 is rotatably connected with the crankcase 4 through a bearing 176. The bearing 176 is arranged at one end close to the connecting piece 171, and a drain groove 18 is arranged between the bearing 176 and the end face of the second end 1422. An oil seal 177 is arranged between the oil pump impeller 175 and the bearing 176, and the oil seal 177 is used for sealing the lubricating oil to prevent leakage of the lubricating oil. A water seal 178 is arranged between the oil seal 177 and the oil pump impeller 175, and the water seal 178 is used for preventing water and other liquids from the outside from entering the engine 100 to avoid failure caused by water entering the engine 100. Among them, the oil pump shaft 172 realizes the connection between the oil pump assembly 17 and the first balance shaft 142, the oil pump body 173 realizes the connection between the oil pump assembly 17 and the crankcase 4, thereby realizing the fixation and rotation of the oil pump assembly 17.

[0052] Specifically, the drain groove 18 communicates the oil pump body 173 and the inside of the crankcase 4, facilitating the oil pump assembly 17 to circulate the lubricating oil in the oil pump body 173 and the inside of the crankcase 4, so that the lubricating oil circulates in the engine 100. The water seal 178 is arranged close to the oil pump impeller 175, which facilitates better sealing of the water seal 178 when the oil pump impeller 175 rotates. The oil seal 177 is close to the bearing 176, which can not only ensure that the lubricating oil lubricates the bearing 176 to reduce the friction between the oil pump shaft 172 and the bearing 176, but also seals the lubricating oil in the engine 100, thereby facilitating the circulation of the lubricating oil in the engine 100. The number of bearings 176 is at least one, thereby ensuring the rotational connection between the oil pump shaft 172 and the crankcase 4.

[0053] It should be understood that for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. An engine, comprising: The cylinder head forms the first accommodating space; An intake and exhaust mechanism, which is at least partially disposed in the first accommodating space, includes an intake mechanism and an exhaust mechanism; A cam mechanism, at least partially disposed in the first accommodating space, is used to control the intake and exhaust mechanism; A crankcase, wherein the crankcase forms a second receiving space; A crankshaft connecting rod mechanism, wherein the crankshaft connecting rod mechanism is at least partially disposed in the second accommodating space; A balancing mechanism, at least partially disposed in the second receiving space and connected to the crankshaft connecting rod mechanism, the balancing mechanism including a first balance shaft and a second balance shaft; Its features are, The engine also includes: An oil pump assembly is connected to the balancing mechanism and the crankcase, and the oil pump assembly is at least partially disposed in the second accommodating space; the oil pump assembly is connected to the first balancing shaft, and the first balancing shaft is used to drive the oil pump assembly; An oil drain groove is at least partially disposed in the second accommodating space and includes a first channel and a second channel. The oil drain groove is disposed between the crankcase and the oil pump assembly and connects the crankcase and the oil pump assembly. The oil drain groove and the crankcase are integrally formed. The first channel is disposed between the crankcase and the oil pump assembly and connects the crankcase and the oil pump assembly, and is used to balance the oil pressure inside the crankcase; The second channel is disposed between the crankcase and the oil pump assembly and connects the crankcase and the oil pump assembly, and is used to form a channel for lubricating oil; The first channel and the second channel are set independently and are not connected; the first channel and the second channel are set in substantially parallel. The first channel is the space where lubricating oil enters, and the second channel is the space where lubricating oil enters. When the lubricating oil splashed by the balancing mechanism enters the oil pump assembly, the oil pump assembly injects the lubricating oil into the oil drain groove. The oil drain groove has a certain gap, and the lubricating oil will be in the second channel. At this time, when the oil pressure increases, the excessive oil pressure will enter the first channel, so as not to affect the delivery of lubricating oil to the crankcase through the oil drain groove, thereby achieving oil pressure balance in the crankcase.

2. The engine according to claim 1, characterized in that, The first balance shaft is provided with a flat square connecting hole, and the oil pump assembly is provided with a connector; the first balance shaft and the oil pump assembly are connected through the flat square connecting hole, and the first balance shaft and the oil pump assembly are also connected through the connector.

3. The engine according to claim 2, characterized in that, The oil pump assembly includes: An oil pump shaft, one end of which is provided with the connecting member for connecting the first balance shaft; an oil pump body, which is rotatably connected to the crankcase, and the oil pump shaft is at least partially disposed in the oil pump body.

4. The engine according to claim 3, characterized in that, The oil pump body is rotatably connected to the crankcase via bearings.

5. The engine according to claim 3, characterized in that, The flat rectangular connecting hole and the connector are connected by a clearance fit.

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