An engine rotating opposed-piston shafting cooling system and engine

Abstract

The application relates to an engine rotating opposed-piston shaft cooling system and an engine, the shaft cooling system comprising a power output shaft and a nested shaft nested with the power output shaft, the power output shaft being provided with a power output shaft oil inlet channel and a power output shaft oil outlet channel along an axis, and the power output shaft being provided with a power output shaft oil inlet manifold and a power output shaft oil outlet manifold corresponding to the power output shaft oil inlet channel and the power output shaft oil outlet channel, the power output shaft oil inlet manifold and the power output shaft oil outlet manifold being provided with different cross sections and being provided with a power output shaft first piston and a power output shaft second piston; the nested shaft being provided with a nested shaft oil inlet channel and an oil outlet channel along an axis, and the nested shaft being provided with a nested shaft oil inlet manifold and a nested shaft oil outlet manifold corresponding to the nested shaft first piston and the nested shaft second piston; and the nested shaft oil inlet ring groove and the nested shaft oil outlet ring groove corresponding to the oil inlet oil pad and the oil outlet oil pad, and forming a nested shaft oil inlet main channel and a nested shaft oil outlet main channel.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine technology, and more specifically to a shaft cooling system for an engine with rotating opposed pistons and an engine. Background Technology

[0002] Due to its unique structure, the rotary opposed piston engine operates at twice the power frequency of a traditional reciprocating piston internal combustion engine at the same speed. For example, patent document CN113006932A discloses a direct-injection rotary opposed piston engine. Compared to the Wankel engine (a triangular piston engine invented in 1954 by Felix Heinrich Wankel in Germany), the rotary opposed piston engine does not suffer from the low thermal efficiency caused by its long and narrow combustion chamber. Compared to a two-stroke engine, the intake and exhaust strokes of the rotary opposed piston engine are relatively independent, resulting in more efficient air exchange. The rotary opposed piston engine eliminates the complex crankshaft and connecting rod mechanism and valve train, achieving miniaturization and weight reduction of the internal combustion engine.

[0003] In addition, the rotary opposed piston engine has a simple structure, runs smoothly and has low noise, effectively breaking through the bottleneck of power improvement of traditional reciprocating piston engines. As a high power density engine, it is expected to be applied to hybrid vehicles, small drones, and auxiliary power systems of armored vehicles.

[0004] Because of its shorter power cycle, the rotary opposed piston engine loses approximately 65% ​​of the heat through coolant compared to a traditional reciprocating piston engine, significantly reducing energy loss during cooling and improving energy transfer efficiency. However, this reduced heat loss through coolant results in a higher thermal load, leading to higher combustion chamber wall temperatures and impacting engine reliability. Since the piston and shaft surfaces are part of the combustion chamber walls, a highly efficient cooling system is required for both the piston and shaft system. As a relatively new type of internal combustion engine, there are currently no reports or documents detailing the design of cooling systems for the piston and shaft system in rotary opposed piston engines.

[0005] Therefore, how to provide a shaft cooling system for an engine with rotating opposed pistons is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Therefore, one object of the present invention is to provide a shaft cooling system for an engine with a rotating opposed piston, and another object is to provide an engine with a rotating opposed piston shaft cooling system to solve the cooling problem of a rotating opposed piston engine.

[0007] This invention provides a shaft cooling system for an engine with rotating opposed pistons, comprising:

[0008] A power output shaft is provided at one end, and the shoulder extends outward to form a piston mounting section of the power output shaft. A first piston and a second piston of the power output shaft are mounted opposite each other on the piston mounting section. The other end of the power output shaft is a nested end. An oil inlet passage and an oil outlet passage of the power output shaft are provided along the axis from one end to the other. A power output shaft manifold and a power output shaft outlet manifold are correspondingly provided between the power output shaft oil inlet passage and the power output shaft outlet manifold. The power output shaft oil inlet manifold and the power output shaft outlet manifold are radially provided corresponding to different cross sections of the power output shaft and are connected to the first piston and the second piston of the power output shaft.

[0009] The power output shaft has one end embedded in a nested shaft hole concentric with it, and extends outward from the nested shaft hole; the shoulder mates with the end face of the nested shaft hole; a first nested shaft piston and a second nested shaft piston are mounted opposite each other on the side of the nested shaft near the shoulder; the nested shaft has a nested shaft oil inlet passage and a nested shaft oil outlet passage along a direction parallel to its axis; the nested shaft has nested shaft oil inlet manifolds and nested shaft oil outlet manifolds communicating with the first nested shaft piston and the second nested shaft piston in different cross-sectional directions;

[0010] The nested shaft has an oil inlet ring groove and an oil outlet ring groove on its outer wall away from the first piston and the second piston of the nested shaft. The oil inlet ring groove and the oil outlet ring groove correspond one-to-one with the oil inlet ring and the oil outlet ring, forming the main oil inlet channel and the main oil outlet channel of the nested shaft.

[0011] Furthermore, the first piston and the second piston of the power output shaft have the same structure. The bottom of the first piston of the power output shaft is provided with a first piston pin of the power output shaft, which cooperates with the first piston pin groove of the power output shaft provided on the piston mounting section of the power output shaft. The second piston pin of the power output shaft at the bottom of the second piston of the power output shaft cooperates with the second piston pin groove of the power output shaft provided on the piston mounting section of the power output shaft.

[0012] The nested shaft first piston and the nested shaft second piston have the same structure. The bottom of the nested shaft first piston is provided with a nested shaft first piston pin, which cooperates with the nested shaft first piston pin groove provided near the shoulder side of the nested shaft. The nested shaft second piston pin cooperates with the nested shaft second piston pin groove provided near the shoulder side of the nested shaft.

[0013] Furthermore, the inner diameter of the oil inlet bearing is the same as the outer diameter of the nested shaft and they are concentrically fitted. The oil inlet bearing has an oil inlet hole and an oil inlet groove. The oil inlet groove and the oil inlet ring groove of the nested shaft form the main oil inlet channel of the nested shaft.

[0014] The inner diameter of the oil outlet bearing is the same as the outer diameter of the nested shaft and they are concentrically fitted. The oil outlet bearing has an oil outlet hole and an oil outlet groove. The oil outlet groove and the oil outlet ring groove of the nested shaft form the main oil outlet channel of the nested shaft.

[0015] Furthermore, the oil inlet manifold and oil outlet manifold of the power output shaft are straight channels and are located at different cross sections of the power output shaft; the oil inlet manifold and oil outlet manifold of the nested shaft are curved channels and are located at different cross sections of the nested shaft.

[0016] Furthermore, the internal oil passages of the first piston and the second piston of the power output shaft each include: the bottom of the first piston of the power output shaft is provided with a piston oil inlet hole and a piston oil outlet hole; one end of the piston oil inlet hole is connected to the oil inlet manifold of the power output shaft, and the other end is connected to the piston end face oil inlet passage; one end of the piston oil outlet hole is connected to the piston end face oil outlet passage, and the other end is connected to the power output shaft oil outlet manifold; the piston end face oil inlet passage and the piston end face oil outlet passage are connected through multiple piston circumferential oil passages.

[0017] Furthermore, the internal oil passages of both the nested shaft first piston and the nested shaft second piston include: the bottom of the nested shaft first piston is provided with a piston oil inlet hole two and a piston oil outlet hole two; one end of the piston oil inlet hole two is connected to the nested shaft oil inlet manifold, and the other end is connected to the piston end face oil inlet passage two; one end of the piston oil outlet hole two is connected to the piston end face oil outlet passage two, and the other end is connected to the nested shaft oil outlet manifold; the piston end face oil inlet passage two and the piston end face oil outlet passage two are connected by multiple piston circumferential oil passages two.

[0018] The present invention provides an engine with a rotating opposed piston shaft cooling system, comprising an engine body and a shaft cooling system for the engine rotating opposed piston as described above, which cooperates with the engine.

[0019] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a shaft cooling system for an engine with a rotating opposed piston. By designing the oil passages of the power output shaft and the nested shaft separately, the oil can flow smoothly through the piston and the internal oil passages of the shaft, thereby achieving reliable cooling of the rotating opposed piston engine.

[0020] The oil inlet and outlet of the power output shaft are both located on the axis of the power output shaft. The oil inlet and outlet of the power output shaft are straight channels. The oil inlet and outlet of the power output shaft are on different cross sections of the power output shaft, which avoids direct communication between the oil inlet and outlet of the power output shaft, thereby avoiding oil short circuit.

[0021] Since the nested shaft has a nested shaft hole along the axial direction and cooperates with the power output shaft, and the nested shaft is a hollow shaft, the nested shaft oil inlet manifold and the nested shaft oil outlet manifold are arc-shaped. The nested shaft oil inlet manifold and the nested shaft oil outlet manifold are in different nested shaft sections, which avoids direct communication between the nested shaft oil inlet manifold and the nested shaft oil outlet manifold, thereby avoiding oil short circuit.

[0022] In a rotary opposed piston engine, each pair of opposed pistons is connected to a power output shaft and a nested shaft, respectively. The two shafts are nested together and supported by the engine block. To achieve the four strokes of exhaust, intake, compression, expansion, and power, the two sets of pistons need to drive the power output shaft and the nested shaft to rotate in the same direction in different modes. The cooling system of this invention ensures reliable cooling of the rotary opposed piston engine. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 The attached figure is an exploded view of a shaft cooling system for a rotating opposed piston engine provided by the present invention;

[0025] Figure 2 The attached figure is a schematic diagram of the structural assembly of a shaft cooling system for an engine with rotating opposed pistons;

[0026] Figure 3 The attached diagram illustrates the structure of the oil passages inside the power take-off shaft;

[0027] Figure 4 The attached image is... Figure 3 Left view of the power take-off shaft;

[0028] Figure 5 The attached diagram is a schematic diagram of the internal oil passages of the nested shaft;

[0029] Figure 6 The attached image is... Figure 5Left view of nested axes;

[0030] Figure 7 The attached diagram shows the internal oil passages and piston pin of the first piston (second piston) of the power take-off shaft.

[0031] Figure 8 The attached image is... Figure 7 A bottom view;

[0032] Figure 9 The attached diagram is a schematic diagram of the internal oil passages and piston pin of the nested shaft first piston (second piston);

[0033] Figure 10 The attached image is... Figure 9 A bottom view;

[0034] Figure 11 The attached diagram is a schematic diagram of the oil outlet bearing structure;

[0035] Figure 12 The attached diagram shows the structure of the oil inlet bearing. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] Due to its simple structure, smooth operation, and low noise, the rotary opposed piston engine effectively overcomes the power bottleneck of traditional reciprocating piston engines. As a high-power-density engine, it holds promise for applications in hybrid vehicles, small drones, and auxiliary power systems for armored vehicles. Its reliable operation relies heavily on cooling. Given the limited research on cooling systems for rotary opposed piston engines, this invention discloses a shaft cooling system for the rotary opposed piston engine. (See attached diagram.) Figure 1-6 ,include:

[0041] A power output shaft 1 has a shoulder 13 at one end, which extends outward to form a piston mounting section. A first piston 3 and a second piston 4 are mounted opposite each other on the piston mounting section. The other end of the power output shaft 1 is a nested end. An oil inlet passage 11 and an oil outlet passage 12 are formed along the axis from one end to the other within the power output shaft 1. A power output shaft inlet manifold and an oil outlet manifold are correspondingly formed between the oil inlet passage 11 and the oil outlet passage 12. The oil outlet manifold is radially opened corresponding to different cross sections of the power output shaft 1 and is connected to the first piston 3 and the second piston 4 of the power output shaft. The engine oil enters the oil inlet passage 11 of the power output shaft through the oil pump, and is split through the oil inlet manifold (oil inlet manifold 111, oil inlet manifold 112) to enter the internal oil passages of the first piston 3 and the second piston 4 of the power output shaft. Then, it merges with the oil outlet passage 12 of the power output shaft through the oil outlet manifold (oil outlet manifold 121, oil outlet manifold 122) and enters the engine oil pan to complete the cooling flow.

[0042] The nested shaft 2 has one end of the power output shaft 1 embedded in the nested shaft hole 21 of the nested shaft 2, which is concentric with it, and extends outward from the nested shaft hole 21; the shoulder 13 is engaged with the end face of the nested shaft hole 21; the nested shaft 2 has a first piston 5 and a second piston 6 mounted opposite each other on the side of the shoulder 13; the nested shaft 2 has a nested shaft oil inlet passage 25 and a nested shaft oil outlet passage 24 along a direction parallel to its axis; the nested shaft 2 has nested shaft oil inlet manifolds (oil inlet manifold three 251, oil inlet manifold four 252) and nested shaft oil outlet manifolds (oil outlet manifold three 241, oil outlet manifold four 242) connected to the first piston 5 and the second piston 6 in different cross-sectional directions;

[0043] The inlet oil bearing 8 and the outlet oil bearing 7 are provided on the outer wall of the nested shaft 2 away from the first piston 5 and the second piston 6 of the nested shaft. The inlet oil bearing 22 and the outlet oil bearing 23 of the nested shaft are provided on the outer wall away from the first piston 5 and the second piston 6 of the nested shaft. The inlet oil bearing 22 and the outlet oil bearing 23 of the nested shaft correspond one-to-one with the inlet oil bearing 8 and the outlet oil bearing 7, and form the main inlet oil channel and the main outlet oil channel of the nested shaft.

[0044] Among them, the nested shaft oil inlet ring groove 22 and the nested shaft oil outlet ring groove 23 are concentric. During the operation of the rotary opposed piston engine, the oil inlet bearing and the oil outlet bearing are stationary, and the nested shaft rotates concentrically relative to them. The nested shaft oil inlet ring groove 22 and the oil inlet bearing 8 form the nested shaft oil inlet main channel, and the nested shaft oil outlet ring groove 23 and the oil outlet bearing 7 form the nested shaft oil outlet main channel.

[0045] Among them, the inlet and outlet oil bearings rotate relative to the nested shaft, while the stationary oil bearings ensure that the inlet and outlet of the nested shaft oil passage remain absolutely stationary, facilitating the connection of external oil pipes.

[0046] The technical solution provided by this invention, through the separate design of the oil passages of the power output shaft and the nested shaft, enables the oil to flow smoothly through the piston and the internal oil passages of the shaft system, thereby achieving reliable cooling of the rotary opposed piston engine.

[0047] See appendix Figure 7 and 8 The first piston 3 and the second piston 4 of the power output shaft have the same structure. Taking the first piston 3 of the power output shaft as an example, the bottom of the first piston 3 of the power output shaft is provided with a first piston pin 31 of the power output shaft. The first piston pin 31 of the power output shaft cooperates with the first piston pin groove 141 of the power output shaft provided on the piston mounting section of the power output shaft 1. The second piston pin of the power output shaft at the bottom of the second piston 4 of the power output shaft cooperates with the second piston pin groove 142 of the power output shaft provided on the piston mounting section of the power output shaft 1.

[0048] See appendix Figure 9 and 10 The nested shaft first piston 5 and the nested shaft second piston 6 have the same structure. Taking the nested shaft first piston 5 as an example, the bottom of the nested shaft first piston 5 is provided with a nested shaft first piston pin 51, which cooperates with the nested shaft first piston pin groove 261 provided on the side of the nested shaft 2 near the shoulder 13; the nested shaft second piston pin cooperates with the nested shaft second piston pin groove 262 provided on the side of the nested shaft 2 near the shoulder 13.

[0049] See appendix Figure 11 and 12 The inner diameter of the oil inlet bearing 8 is the same as the outer diameter of the nested shaft 2 and they are concentrically fitted. The oil inlet bearing 8 is provided with an oil inlet hole 82 and an oil inlet groove 81. The oil inlet groove 81 and the nested shaft oil inlet ring groove 22 form the main channel for oil inlet of the nested shaft.

[0050] The inner diameter of the oil outlet bearing 7 is the same as the outer diameter of the nested shaft and they are concentrically fitted. The oil outlet bearing 7 has an oil outlet hole 72 and an oil outlet groove 71. The oil outlet groove 71 and the oil outlet ring groove 23 of the nested shaft form the main channel for oil outlet of the nested shaft.

[0051] Advantageously, the oil inlet manifold and oil outlet manifold of the power output shaft are straight channels and are located at different cross sections of the power output shaft 1; the oil inlet manifold and oil outlet manifold of the nested shaft are curved channels and are located at different cross sections of the nested shaft 2.

[0052] Specifically, the oil inlet manifold (oil inlet manifold 111, oil inlet manifold 212) and oil outlet manifold (oil outlet manifold 121, oil outlet manifold 2122) of the power output shaft are straight channels. The oil inlet manifold and oil outlet manifold of the power output shaft are on different cross sections of the power output shaft, which avoids direct communication between the oil inlet 11 and the oil outlet 12 of the power output shaft, thereby avoiding oil short circuit; because the nested shaft 2 is along the axial direction The shaft has a shaft hole 21 that mates with the shoulder 13 of the power output shaft. The nested shaft 2 is a hollow shaft. Therefore, the oil inlet manifold (oil inlet manifold 3 251, oil inlet manifold 4 252) and the oil outlet manifold (oil outlet manifold 3 241, oil outlet manifold 4 242) of the nested shaft are arc-shaped. The oil inlet manifold and the oil outlet manifold of the nested shaft are in different cross sections of the nested shaft, which avoids direct communication between the oil inlet manifold and the oil outlet manifold of the nested shaft, and thus avoids short circuit of the oil.

[0053] Specifically, the internal oil passages of the first piston 3 and the second piston 4 of the power output shaft both include: the bottom of the first piston 3 of the power output shaft is provided with a piston oil inlet hole 32 and a piston oil outlet hole 36, one end of the piston oil inlet hole 32 is connected to the power output shaft oil inlet manifold, and the other end is connected to the piston end face oil inlet passage 33; one end of the piston oil outlet hole 36 is connected to the piston end face oil outlet passage 35, and the other end is connected to the power output shaft oil outlet manifold; the piston end face oil inlet passage 33 and the piston end face oil outlet passage 35 are connected by multiple piston circumferential oil passages 34.

[0054] The internal oil passages of the nested shaft first piston 5 and the nested shaft second piston 6 both include: the bottom of the nested shaft first piston 5 is provided with a piston oil inlet hole 2 52 and a piston oil outlet hole 2 56, one end of the piston oil inlet hole 2 52 is connected to the nested shaft oil inlet manifold, and the other end is connected to the piston end face oil inlet passage 2 53; one end of the piston oil outlet hole 2 56 is connected to the piston end face oil outlet passage 2 55, and the other end is connected to the nested shaft oil outlet manifold; the piston end face oil inlet passage 2 53 and the piston end face oil outlet passage 2 55 are connected by multiple piston circumferential oil passages 2 54.

[0055] The present invention also provides an engine with a rotating opposed piston shaft cooling system, comprising an engine body and a shaft cooling system for the engine's rotating opposed pistons that cooperate with the engine. In the rotating opposed piston engine, each pair of opposed pistons is respectively connected to a power output shaft and a nested shaft, with the two shafts nested together and supported by the engine block.

[0056] In this invention, the two pairs of opposing pistons 3 and 4, 5 and 6 of the rotary opposed piston engine drive the corresponding power output shaft 1 and nested shaft 2 to rotate. For the power output shaft 1, the first piston 3, and the second piston 4, the engine oil enters the power output shaft oil inlet passage 11 opened in the center of the power output shaft 1 through the oil pump. After passing through the power output shaft oil inlet manifold (oil inlet manifold 111, oil inlet manifold 212), it flows into the oil inlet hole at the bottom of the piston. Inside the piston, it passes through the piston end face oil inlet passage 1, the piston circumferential oil passage 1, the piston end face oil outlet passage 1, and the piston oil outlet hole before entering the power output shaft oil outlet manifold (oil outlet manifold 121, oil outlet manifold 2122). It then merges with the power output shaft oil outlet passage 12 through the oil outlet manifold and flows to the engine oil pan to complete the cooling.

[0057] For the nested shaft 2, nested shaft first piston 5, nested shaft second piston 6, oil outlet bearing 7, and oil inlet bearing 8, the engine oil enters through the oil inlet bearing oil inlet hole 82 opened on the oil inlet bearing via the oil pump, enters the nested shaft oil inlet main channel formed by the nested shaft oil inlet ring groove 22 and the oil inlet bearing 8, enters the nested shaft oil inlet passage 25 through the nested shaft oil inlet ring passage, and is split into the nested shaft oil inlet manifold (oil inlet manifold three 251, oil inlet manifold four 252) and enters the oil inlet holes of the nested shaft first piston 5 and nested shaft second piston 6, flows through the piston end face oil inlet passage two and piston circumference. After exiting the second oil passage and the piston end face, the oil flows through the oil outlet holes of the first piston 5 and the second piston 6 of the nested shaft into the nested shaft oil outlet manifold (oil outlet manifold 3 241, oil outlet manifold 4 242). After merging through the nested shaft oil outlet manifold (oil outlet manifold 3 241, oil outlet manifold 4 242), it enters the nested shaft oil outlet passage 24. The nested shaft oil outlet passage 24 flows to the nested shaft main oil outlet channel formed by the oil outlet bearing 7 and the nested shaft oil outlet ring groove 23. It flows out through the oil outlet bearing oil outlet hole 72 opened on the oil outlet bearing and enters the engine oil pan to complete the cooling.

[0058] In this invention, the first piston of the power output shaft, the second piston of the power output shaft, the first piston of the nested shaft, and the second piston of the nested shaft are provided with piston pins at their bottoms and have the same structural dimensions. The power output shaft and the nested shaft are provided with piston pin grooves and have the same structural dimensions. The piston pins and piston pin grooves cooperate to realize the synchronous rotation of the shaft and the piston during the engine operation process. This further ensures that the piston oil inlet hole and the corresponding shaft oil inlet manifold are always connected during the engine operation process, and the piston oil outlet hole and the corresponding shaft oil outlet manifold are always connected.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A shaft cooling system for an engine with rotating opposed pistons, characterized in that, include: A power output shaft (1) is provided at one end with a shoulder (13), and the shoulder (13) extends outward to form a piston mounting section of the power output shaft. The piston mounting section is provided with a first piston (3) and a second piston (4) of the power output shaft. The other end of the power output shaft (1) is a nested end. A power output shaft oil inlet passage (11) and a power output shaft oil outlet passage (12) are provided along the axis from one end to the other in the power output shaft (1). A power output shaft oil inlet manifold and a power output shaft oil outlet manifold are provided between the power output shaft oil inlet passage (11) and the power output shaft oil outlet passage (12). The power output shaft oil inlet manifold and the power output shaft oil outlet manifold are radially opened corresponding to different cross sections of the power output shaft (1) and are connected to the first piston (3) and the second piston (4) of the power output shaft. The nested shaft (2) has the other end of the power output shaft (1) embedded in the nested shaft hole (21) of the nested shaft (2) which is concentric with it, and extends outward from the nested shaft hole (21); the shoulder (13) is engaged with the end face of the nested shaft hole (21); the nested shaft (2) has a first piston (5) and a second piston (6) mounted opposite each other on the side of the shoulder (13); the nested shaft (2) has a nested shaft oil inlet passage (25) and a nested shaft oil outlet passage (24) opened in a direction parallel to its axis; the nested shaft (2) has a nested shaft oil inlet manifold and a nested shaft oil outlet manifold communicating with the first piston (5) and the second piston (6) in different cross-sectional directions; The inlet oil bearing (8) and outlet oil bearing (7) are provided on the outer wall of the nested shaft (2) away from the first piston (5) and the second piston (6) of the nested shaft. The inlet oil bearing (22) and outlet oil bearing (23) correspond one-to-one with the inlet oil bearing (8) and the outlet oil bearing (7), forming the main inlet oil channel and the main outlet oil channel of the nested shaft.

2. The shaft cooling system for an engine with rotating opposed pistons according to claim 1, characterized in that, The first piston (3) and the second piston (4) of the power output shaft have the same structure. The bottom of the first piston (3) of the power output shaft is provided with a first piston pin (31) of the power output shaft. The first piston pin (31) of the power output shaft cooperates with the first piston pin groove (141) of the power output shaft provided on the piston mounting section of the power output shaft (1). The second piston pin of the power output shaft at the bottom of the second piston (4) of the power output shaft cooperates with the second piston pin groove (142) of the power output shaft provided on the piston mounting section of the power output shaft (1). The nested shaft first piston (5) and the nested shaft second piston (6) have the same structure. The nested shaft first piston (5) is provided with a nested shaft first piston pin (51) at the bottom, which cooperates with the nested shaft first piston pin groove (261) provided on the side of the nested shaft (2) near the shoulder (13). The nested shaft second piston pin cooperates with the nested shaft second piston pin groove (262) provided on the side of the nested shaft (2) near the shoulder (13).

3. The shaft cooling system for an engine with rotating opposed pistons according to claim 1, characterized in that, The inner diameter of the oil inlet bearing (8) is the same as the outer diameter of the nested shaft (2) and they are concentrically fitted. The oil inlet bearing (8) is provided with an oil inlet hole (82) and an oil inlet groove (81). The oil inlet groove (81) and the nested shaft oil inlet ring groove (22) form the main channel for the nested shaft oil inlet. The inner diameter of the oil outlet bearing (7) is the same as the outer diameter of the nested shaft and they are concentrically fitted. The oil outlet bearing (7) is provided with an oil outlet hole (72) and an oil outlet groove (71). The oil outlet groove (71) and the oil outlet ring groove (23) of the nested shaft form the main channel for oil outlet of the nested shaft.

4. The shaft cooling system for an engine with rotating opposed pistons according to claim 1, characterized in that, The oil inlet manifold and oil outlet manifold of the power output shaft are straight channels and are located at different sections of the power output shaft (1); the oil inlet manifold and oil outlet manifold of the nested shaft are arc-shaped channels and are located at different sections of the nested shaft (2).

5. A shaft cooling system for an engine with rotating opposed pistons according to claim 2, characterized in that, The internal oil passages of the first piston (3) and the second piston (4) of the power output shaft both include: the bottom of the first piston (3) of the power output shaft is provided with a piston oil inlet hole (32) and a piston oil outlet hole (36), one end of the piston oil inlet hole (32) is connected to the power output shaft oil inlet manifold, and the other end is connected to the piston end face oil inlet passage (33); one end of the piston oil outlet hole (36) is connected to the piston end face oil outlet passage (35), and the other end is connected to the power output shaft oil outlet manifold; the piston end face oil inlet passage (33) and the piston end face oil outlet passage (35) are connected through multiple piston circumferential oil passages (34).

6. A shaft cooling system for an engine with rotating opposed pistons according to claim 2, characterized in that, The internal oil passages of the nested shaft first piston (5) and the nested shaft second piston (6) both include: the bottom of the nested shaft first piston (5) is provided with piston oil inlet hole two (52) and piston oil outlet hole two (56), one end of piston oil inlet hole two (52) is connected to the nested shaft oil inlet manifold, and the other end is connected to piston end face oil inlet passage two (53); one end of piston oil outlet hole two (56) is connected to piston end face oil outlet passage two (55), and the other end is connected to nested shaft oil outlet manifold; piston end face oil inlet passage two (53) and piston end face oil outlet passage two (55) are connected by multiple piston circumferential oil passage two (54).

7. An engine having a rotating opposed piston shaft cooling system, comprising an engine body and a shaft cooling system for an engine rotating opposed piston as described in any one of claims 1-6, cooperating with the engine.

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