Reciprocating internal combustion engine

Abstract

To realize a reciprocating internal combustion engine that easily reduces the vibrations generated. [Solution] The reciprocating internal combustion engine 100 comprises a first piston member 12A, a first planetary gear mechanism 21A, a first counter rotating member 31A, a second piston member 12B, a second planetary gear mechanism 21B, a second counter rotating member 31B, an interlocking mechanism 32, and an output member 4. The first piston member 12A is connected to the first counter rotating member 31A via the first planetary gear mechanism 21A. The second piston member 12B is connected to the second counter rotating member 31B via the second planetary gear mechanism 21B. The interlocking mechanism 32 interlocks the first counter rotating member 31A and the second counter rotating member 31B so that they rotate at the same rotational speed. The output member 4 rotates in conjunction with the rotating members that rotate in conjunction with the rotating members constituting the interlocking mechanism 32.

Description

Technical Field

[0001] The present invention relates to a reciprocating internal combustion engine.

Background Art

[0002] Techniques related to reciprocating internal combustion engines are disclosed, for example, in Patent Document 1. In the following description of this background art, the reference numerals and names in Patent Document 1 are cited within parentheses.

[0003] Patent Document 1 discloses a reciprocating internal combustion engine (opposed piston type engine A) including a cylinder (horizontal cylinder 1), a first piston member (left piston 2) and a second piston member (right piston 3) that reciprocate within the cylinder (horizontal cylinder 1). The reciprocating internal combustion engine (opposed piston type engine A) disclosed in Patent Document 1 is of an opposed type in which the first piston member (left piston 2) and the second piston member (right piston 3) reciprocate within the same cylinder (horizontal cylinder 1), thereby reducing the vibration generated by the reciprocating motion of the first piston member (left piston 2) and the second piston member (right piston 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the reciprocating internal combustion engine (opposed piston type engine A) disclosed in Patent Document 1, since the reciprocating motion of the first piston member (left piston 2) and the second piston member (right piston 3) is converted into a rotational motion by a crank mechanism (left and right crank mechanisms 17, 18), secondary vibration is likely to occur.

[0006] Therefore, there is a need to realize a reciprocating internal combustion engine that can easily reduce the vibrations that occur. [Means for solving the problem]

[0007] The reciprocating internal combustion engine according to this disclosure comprises a first planetary gear mechanism comprising: a first ring gear which is an internal gear; a first carrier rotatably supported with respect to the first ring gear; a first planetary gear which is rotatably supported with respect to the first carrier and meshes with the first ring gear; a first crank member which is connected to rotate integrally with the first planetary gear; a first piston member which is connected to the first crank member so as to rotate relative to it about a first input axis which is set at a position spaced apart from the first planetary axis which is the rotation axis of the first planetary gear; a first counter rotating member which rotates in the opposite direction to the first carrier at the same rotational speed in conjunction with the rotation of the first carrier; a second ring gear which is an internal gear; a second carrier which is rotatably supported with respect to the second ring gear; and a first counter rotating member which is rotatably supported with respect to the second carrier. The device comprises a second planetary gear mechanism comprising a second planetary gear that meshes with the second ring gear, a second crank member connected to rotate integrally with the second planetary gear, a second piston member connected to the second crank member so as to be rotatable relative to a second input axis set at a position spaced apart from the second planetary axis which is the rotation axis of the second planetary gear, a second counter rotating member that rotates in the opposite direction to the second carrier at the same rotational speed in conjunction with the rotation of the second carrier, an interlocking mechanism that interlocks the first counter rotating member and the second counter rotating member so that they rotate at the same rotational speed, and an output member that rotates in conjunction with the first carrier, the second carrier, the first counter rotating member, the second counter rotating member, and the interlocking mechanism.

[0008] With this configuration, the planetary gear mechanism, which has less difference in piston speed change between the forward and return strokes compared to a crank mechanism, converts the reciprocating motion of the first and second piston members into rotational motion, making it easier to suppress secondary vibrations. In addition, the primary vibrations caused by the reciprocating motion of the first and second piston members can be effectively reduced by the first counter rotating member and the second counter member. Therefore, it is easier to reduce vibrations generated from the entire reciprocating internal combustion engine.

[0009] Further features and advantages of the technology relating to this disclosure will become clearer from the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 1 [Figure 2] Section II-II in Figure 1 [Figure 3] Section III-III in Figure 1 [Figure 4] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 2 [Figure 5] VV section view in Figure 4 [Figure 6] Figure 4, section VI-VI [Figure 7] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 3 [Figure 8] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 4 [Figure 9] Figure 8: Cross-sectional view of section IX-IX [Figure 10] Cross-sectional view of XX in Figure 8 [Figure 11] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 5 [Figure 12] Figure 11 shows the cross-sectional view between XII and XII. [Figure 13] Cross-sectional view of the reciprocating internal combustion engine of Embodiment 6 [Figure 14] Figure 13: Cross-sectional view between XIV and XIV [Modes for carrying out the invention]

[0011] 〔Embodiment 1〕 The reciprocating internal combustion engine 100 of Embodiment 1 will be described with reference to FIGS. 1 to 3.

[0012] The reciprocating internal combustion engine 100 is, for example, an engine that serves as a drive source for a rotating machine that operates by a generator, a pump, or other rotational force. Specifically, the reciprocating internal combustion engine 100 converts the energy of the combustion gas burned in the combustion chamber into a reciprocating motion. Then, the reciprocating internal combustion engine 100 converts the reciprocating motion into a rotational motion and outputs it.

[0013] As shown in FIG. 1, the reciprocating internal combustion engine 100 includes a reciprocating unit 1, a power conversion unit 2, an output member 4, a vibration reduction structure 3, and a case 5 that houses these components. The reciprocating unit 1 converts the energy of the combustion gas into a reciprocating motion. The power conversion unit 2 converts the reciprocating motion taken out by the reciprocating unit 1 from the combustion gas into a rotational motion. The output member 4 is used to output the rotational motion.

[0014] The reciprocating unit 1 includes a cylinder 11 that forms a combustion chamber in which air mixed with fuel burns, and a piston member 12 that reciprocates within the cylinder. The cylinder 11 is a cylindrical container having a wall that surrounds the outer periphery of the combustion chamber, and the piston member 12 is a member that covers the combustion chamber from the side. Around the combustion chamber, at least an intake port for sending air into the combustion chamber, an exhaust port for discharging air containing combustion gas outside the combustion chamber, and an injector for mixing air and fuel (not shown) are arranged.

[0015] The piston member 12 reciprocates along the longitudinal direction of the cylinder 11 to perform each step of the combustion cycle, which consists of a step of taking air into the combustion chamber, a step of burning the gas mixture of fuel and air, and a step of exhausting the gas after combustion from the combustion chamber. Here, since the detailed structure of the reciprocating unit 1 is easier to understand based on the direction in which the piston member 12 reciprocates, in this specification, the direction in which the piston member 12 reciprocates is referred to as the reciprocating direction I. In the reciprocating direction I, the side closer to the combustion chamber is referred to as the inner side I1 of the reciprocating direction, and the side away from the combustion chamber is referred to as the outer side I2 of the reciprocating direction. Also, the direction orthogonal to the reciprocating direction I is referred to as the cylinder radial direction H.

[0016] The piston member 12 includes a piston body 121 that forms a wall covering the combustion chamber from the side, and a connecting rod 122 that connects the piston body 121 and the power conversion unit 2.

[0017] The piston body 121 moves between the top dead center and the bottom dead center within the cylinder 11. The top dead center is the position that is the most inner side I1 in the reciprocating direction among the positions where the piston body 121 can move within the cylinder. On the other hand, the bottom dead center is the position that is the most outer side I2 in the reciprocating direction among the positions where the piston body 121 can move within the cylinder. The specific positions of the top dead center and the bottom dead center are determined by the shape of the connecting rod 122 and the structure of the power conversion unit 2. The piston body 121 moves from the top dead center toward the bottom dead center by receiving the expansion pressure of the combustion gas on the surface arranged on the inner side I1 of the reciprocating direction, and moves from the bottom dead center toward the top dead center as the air in the combustion chamber is discharged to the outside of the combustion chamber through the exhaust port. In the example shown in FIG. 1, the state where the piston member 12 is arranged at the top dead center is shown.

[0018] The connecting rod 122 is a member that extends along the reciprocating direction I. The inner end I1 of the connecting rod 122 in the reciprocating direction is connected to the outer portion I2 of the piston body 121 in the reciprocating direction, and the outer end I2 of the connecting rod 122 in the reciprocating direction is connected to the power conversion unit 2. The power conversion unit 2 converts the reciprocating motion transmitted from the piston body 121 via the connecting rod 122 into rotational motion. In this embodiment, the connecting rod 122 is provided with a pair of connecting portions 123 on both sides in a direction perpendicular to the reciprocating direction I. Each of the pair of connecting portions 123 extends along the reciprocating direction I, and its outer end I2 in the reciprocating direction is connected to the power conversion unit 2.

[0019] In this embodiment, the power conversion unit 2 includes a planetary gear mechanism 21 for outputting rotational motion to an output member 4, and a crank member 22 for connecting the planetary gear mechanism 21 to a connecting rod 122.

[0020] The planetary gear mechanism 21 includes an internal gear, a ring gear RG; a carrier C rotatably supported relative to the ring gear RG; and a planetary gear PG rotatably supported relative to the carrier C and meshing with the ring gear RG. The reciprocating motion of the piston body 121 is transmitted to the planetary gear PG via the connecting rod 122 and the crank member 22, and output as rotational motion by the carrier C. In this embodiment, the carrier C includes an output unit 21C that outputs rotational motion. Figure 1 shows an external gear that rotates together with the carrier C as an example of the output unit 21C.

[0021] The ring gear RG is positioned outward I2 in the reciprocating direction relative to the cylinder 11. In this embodiment, the ring gear RG is positioned such that, when viewed from the reciprocating direction I, the axis of the ring gear RG coincides with the center position of the cylinder 11 in the cylinder radial direction H. The planetary gear PG is supported by the carrier C so as to be movable along the inner circumference of the ring gear RG while meshing with it. Therefore, the carrier C has a rotational axis (carrier axis XC) that coincides with the axis of the ring gear RG, and rotates around the carrier axis XC in conjunction with the movement of the planetary gear PG along the inner circumferential surface of the ring gear RG.

[0022] Here, since the planetary gear mechanism 21 outputs rotational motion from the carrier C, the arrangement relationship between the planetary gear mechanism 21 and the crank member 22, and the arrangement relationship between the planetary gear mechanism 21 and the vibration reduction structure 3, is easier to understand when viewed with reference to the carrier axis XC. Therefore, in this specification, the direction along the carrier axis XC is referred to as the axial direction X. One side in the axial direction X is referred to as the axial first side X1, and the other side in the axial direction X is referred to as the axial second side X2.

[0023] As shown in Figure 2, the crank member 22 is connected to the planetary gear PG so as to rotate integrally with the planetary gear PG. The crank member 22 comprises a planetary shaft 221 that supports the planetary gear PG, an input shaft 22Z to which reciprocating motion is input, and an arm 222 that connects the input shaft 22Z to the planetary shaft 221 so as not to move relative to it. The input shaft 22Z has an axis (input axis XZ) extending in the axial direction X, and is rotatably supported by the connecting part 123 via a connecting bearing 23. The planetary shaft 221 rotates together with the planetary gear PG and has the same axis of rotation as the axis of rotation of the planetary gear PG (planetary axis XP).

[0024] The piston member 12 is connected to the crank member 22 so as to be able to rotate relative to it around the input axis XZ, which is set at a position spaced apart from the planet axis XP. In this embodiment, the input axis XZ is positioned at a position spaced apart from the planet axis XP in the planetary radial direction R, which is perpendicular to the planet axis 221. In this embodiment, the planet axis 221 is positioned such that the planet axis XP is parallel to the input axis XZ. To achieve this positional relationship, the arm 222 is a member that extends in the reciprocating direction I and the cylinder radial direction H. In the example shown in Figure 2, the input axis 22Z and the planet axis 221 are fixed to the arm 222 so as to protrude in opposite directions along the axial direction X.

[0025] In this embodiment, the crank member 22 comprises a pair of input shafts 22Z and a pair of arms 222, which are spaced apart in the axial direction X. One of the pair of input shafts 22Z is ​​connected to one of the pair of connecting parts 123, and the other of the pair of input shafts 22Z is ​​connected to the other of the pair of connecting parts 123. The planetary shaft 221 has its axial first side X1 end fixed to one of the pair of arms 222, and its axial second side X2 end fixed to the other of the pair of arms 222. With this configuration, the planetary gear mechanism 21 can be positioned to overlap with the piston body 121 when viewed from the reciprocating direction I, so that a load biased towards the axial direction X is less likely to be applied to the connection structure between the planetary gear mechanism 21 and the connecting rod 122 and its surrounding structure.

[0026] As the piston body 121 reciprocates within the cylinder 11, the input shaft 22Z reciprocates within a certain range, tracing a linear trajectory along the reciprocating direction I. As a result, the arm 222 and the planetary shaft 221 rotate relative to each other around the input axis XZ, which moves along the reciprocating direction I, and the entire crank member 22 revolves together with the planetary gear PG around the axis of the ring gear RG. With this configuration, the difference in velocity change when the piston body 121 moves from bottom dead center to top dead center, and when the piston body 121 moves from top dead center to bottom dead center, is reduced.

[0027] The reciprocating unit 1 described above comprises a pair of piston members 12, and the reciprocating internal combustion engine 100 comprises a pair of power conversion units 2 connected to each of the pair of piston members 12. In this specification, one of the pair of piston members 12 is referred to as the first piston member 12A, and the other of the pair of piston members 12 is referred to as the second piston member 12B. Also, one of the pair of power conversion units 2 is referred to as the first power conversion unit 2A, and the other of the pair of power conversion units 2 is referred to as the second power conversion unit 2B.

[0028] The first piston member 12A is connected to the first power conversion unit 2A, as shown in Figure 2. The second piston member 12B is connected to the second power conversion unit 2B, as shown in Figure 3.

[0029] In this specification, the crank member 22 and the planetary gear mechanism 21 of the first power conversion unit 2A are referred to as the first crank member 22A and the first planetary gear mechanism 21A, respectively, and in the first crank member 22A, the input axis XZ is referred to as the first input axis XZA. The ring gear RG, carrier C, and planetary gear PG of the first planetary gear mechanism 21A are referred to as the first ring gear RGA, the first carrier CA, and the first planetary gear PGA, respectively. The first rotation axis, which is the carrier axis XC of the first carrier CA, is referred to as the first carrier axis XCA, and the planetary axis XP of the first planetary gear PGA is referred to as the first planetary axis XP1.

[0030] Similarly, the crank member 22 and the planetary gear mechanism 21 of the second power conversion unit 2B are referred to as the second crank member 22B and the second planetary gear mechanism 21B, respectively, and the input axis XZ of the second crank member 22B is referred to as the second input axis XZB. The ring gear RG, carrier C, and planetary gear PG of the second gear mechanism are referred to as the second ring gear RGB, the second carrier CB, and the second planetary gear PGB, respectively. The second rotation axis, which is the carrier axis XC of the second carrier CB, is referred to as the second carrier axis XCB, and the planetary axis XP of the second planetary gear PGB is referred to as the second planetary axis XP2.

[0031] Here, it was explained that the axial direction X is determined with respect to the carrier axis XC. And, in this embodiment, since there is a pair of carriers C, it is preferable to distinguish the axial direction X in accordance with the pair of carrier axes XC. However, as will be described later, in this embodiment, the first carrier axis XCA and the second carrier axis XCB are in a positional relationship parallel to each other, so in this specification, the axial direction X is defined as the direction along the first carrier axis XCA and the second carrier axis XCB.

[0032] In this embodiment, the reciprocating unit 1 is of the opposing type, as shown in Figure 1, in which a pair of piston members 12 are arranged in positions facing each other. More specifically, both the first piston member 12A and the second piston member 12B slide within the same cylinder 11. In order to arrange the pair of piston members 12 facing each other, the cylinder 11 has openings at both ends along the reciprocating direction I. The first piston member 12A is positioned in one of the openings of the cylinder 11, and the second piston member 12B is positioned in the other opening of the cylinder 11. Thus, the combustion chamber is surrounded by the wall of the cylinder 11, the piston body 121 of the first piston member 12A, and the piston body 121 of the second piston member 12B.

[0033] In this embodiment, since the reciprocating unit 1 is of the opposing type, the first power conversion unit 2A and the second power conversion unit 2B are arranged opposite each other with the first piston member 12A and the second piston member 12B in between, from the viewpoint of vibration reduction and structural simplification. The first carrier axis XCA, which is the carrier axis XC of the first carrier CA, and the second carrier axis XCB, which is the carrier axis XC of the second carrier CB, are arranged parallel to each other. In detail, the first piston member 12A and the second piston member 12B are arranged in opposite directions to each other so that they reciprocate along the reference axis. Here, the reference line is an imaginary line connecting the first carrier axis XCA and the second carrier axis XCB in an axial view along the axial direction X.

[0034] As shown in Figure 1, the vibration reduction structure 3 comprises a counter rotating member 31 and an interlocking mechanism 32. The counter rotating member 31 and the interlocking mechanism 32 reduce the primary vibration generated by the reciprocating piston member 12 at each reciprocating cycle. In this embodiment, the vibration reduction structure 3 further comprises a balancer 33. The balancer 33 further reduces the primary vibration reduced by the counter rotating member 31 and the interlocking mechanism 32, and also reduces vibration caused by torque fluctuations that occur in the piston member 12 as each process of the combustion cycle progresses.

[0035] The counter rotating member 31 rotates in the opposite direction to the carrier C of the planetary gear mechanism 21 at the same rotational speed, in conjunction with the rotation of the carrier C. With this configuration, the counter rotating member 31 cancels out at least a portion of the vibration component of the primary vibration generated by the piston member 12.

[0036] In this embodiment, as shown in Figures 1 and 2, the counter rotating member 31 includes an input unit 311 to which rotation is transmitted from the output unit 21C of the carrier C, a counter shaft 312 that rotates together with the input unit 311, and a wheel 313 that rotates together with the counter shaft 312. In this embodiment, the input unit 311 is a gear that meshes with the output unit 21C, which is an external gear. The counter shaft 312 has a rotation axis parallel to the carrier axis XC and is rotatably supported by the case 5. In the example shown in Figures 1 and 2, the input unit 311 and the counter shaft 312 are an integrated structure.

[0037] The wheel 313 is a rotating body that cancels out the primary vibrations generated by the reciprocating unit 1 and the power conversion unit 2. The wheel 313 is a rotating body whose center of gravity is located at a position spaced apart from the carrier axis XC when viewed from the axial direction X, so as to cancel out the primary vibrations generated by the reciprocating unit 1 and the power conversion unit 2. In detail, the wheel 313 is a rotating body having the same axis of rotation as the counter shaft 312 and is connected to the counter shaft 312 so as to rotate together with the counter shaft 312. In the example shown in Figure 2, the wheel 313 also serves as the input section 311, and the input section 311 is provided on the outer circumference of the wheel 313.

[0038] The vibration reduction structure 3 includes a pair of counter-rotating members 31 to reduce vibrations of the pair of piston members 12 and the pair of power conversion units 2. Hereafter, for the sake of explanation, one of the pair of counter-rotating members 31 will be referred to as the first counter-rotating member 31A, and the other of the pair of counter-rotating members 31 will be referred to as the second counter-rotating member 31B. The first counter-rotating member 31A rotates in the opposite direction to the first carrier CA of the first planetary gear mechanism 21A at the same rotational speed. On the other hand, the second counter-rotating member 31B rotates in the opposite direction to the second carrier CB of the second planetary gear mechanism 21B at the same rotational speed.

[0039] As shown in Figure 1, the interlocking mechanism 32 interlocks the first counter rotating member 31A and the second counter rotating member 31B so that they rotate at the same rotational speed. With this configuration, much of the vibration component of the primary vibration caused by the reciprocating motion of the first piston member 12A and the second piston member 12B can be effectively canceled out. In this embodiment, the interlocking mechanism 32 drives and connects the wheel 313 of the first counter rotating member 31A and the wheel 313 of the second counter rotating member 31B so that they rotate in the same direction and at the same rotational speed.

[0040] Herein, in this application, "driving connection" refers to a state in which two rotating elements are connected in a manner that can transmit driving force. This state includes a state in which the two rotating elements are connected so as to rotate as a whole, or a state in which the two rotating elements are connected in a manner that can transmit driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at a variable speed, such as shafts, gear mechanisms, belts, chains, etc. In addition, the transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices, meshing engagement devices, etc.

[0041] In this embodiment, the interlocking mechanism 32 includes, as shown in Figure 2, a first interlocked gear 321 provided on the first counter rotating member 31A, a second interlocked gear 322 provided on the second counter rotating member 31B, and an interlocking gear 323, as shown in Figure 3. The interlocking gear 323 is an external gear that meshes with both the first interlocked gear 321 and the second interlocked gear 322. In this embodiment, the first interlocked gear 321 has the same rotational axis as the counter shaft 312 of the first counter rotating member 31A and is an external gear positioned on the second axial side X2 with respect to the wheel 313 of the first counter rotating member 31A. On the other hand, the second interlocked gear 322 has the same rotational axis as the counter shaft 312 of the second counter rotating member 31B and is an external gear positioned on the second axial side X2 with respect to the wheel 313 of the second counter rotating member 31B. The number of teeth and pitch circle diameter of the second linked gear 322 are set to be the same as the number of teeth and pitch circle diameter of the first linked gear 321.

[0042] The output member 4 rotates in conjunction with the first carrier CA, the second carrier CB, the first counter rotating member 31A, the second counter rotating member 31B, and the interlocking mechanism 32. More specifically, the output member 4 is connected to rotate integrally with the first carrier CA, the second carrier CB, the first counter rotating member 31A, the second counter rotating member 31B, and the interlocking mechanism 32, or with gears, shafts, or other rotating members that rotate together with them. Here, for one rotating member to rotate in conjunction with another rotating member, for example, a gear, which is an example of one rotating member, meshes with a gear, which is an example of another rotating member, and they rotate together. For example, the interlocking gear shaft 41, which rotatably supports the interlocking gear 323 in the case 5, rotates integrally with the output member 4.

[0043] The output member 4 is connected to the first load L1. The first load L1 converts rotational motion into a form appropriate to the application. For example, the first load L1 can be a generator or a wheel. If the first load L1 is a generator, the output member 4 is driven and connected to the rotating shaft of the generator, and rotates the shaft to generate electricity. Alternatively, if the first load L1 is a wheel, the output member 4 is driven and connected to the axle of the wheel, and rotates the axle to move the vehicle. Preferably, the moment of inertia of the rotating part of the first load L1 is set taking into consideration the primary vibration generated by the reciprocating unit 1 and the power conversion unit 2 during operation.

[0044] The balancer 33 is a group of masses that cancel out the vibration components of primary vibrations and torque fluctuations caused by the reciprocating motion of the piston member 12 within the cylinder 11. Here, the group of masses includes multiple masses. The masses include members that are detachably attached to the rotating member and a part of the rotating member. The balancer 33 comprises a main balancer 33M, a counter balancer 33S, and a torque balancer 33T.

[0045] The main balancer 33M is a mass that rotates in the same direction as the carrier C of the planetary gear mechanism 21. With this configuration, at least a portion of the vibration component of the primary vibration caused by the reciprocating motion of the piston member 12 can be canceled out. In detail, the main balancer 33M comprises a first balance weight 1M and a second balance weight 2M. The first balance weight 1M cancels out at least a portion of the vibration component of the primary vibration caused by the first piston member 12A. The second balance weight 2M cancels out at least a portion of the vibration component of the primary vibration caused by the second piston member 12B.

[0046] The first balance weight 1M is a mass that rotates in the same direction as the first carrier CA. In this embodiment, the first balance weight 1M is a mass that constitutes a part of the first carrier CA. The first balance weight 1M shown in Figures 1 and 2 is an integral structure with the first carrier CA and is a portion that protrudes from the outer circumference of the first carrier CA toward the first axial direction X1. The position and range occupied by the first balance weight 1M in the first carrier CA, as viewed from the axial direction X, are determined in relation to the surrounding structure and so that the center of gravity of the first balance weight 1M is in a position appropriate for reducing first-order vibrations.

[0047] The first balance weight 1M is positioned such that its center of gravity and the positional relationship between it and the first planetary axis XP1 are opposite each other when viewed from the axial direction X, with the first carrier axis XCA in between. In Figure 1, the first balance weight 1M is positioned such that its center of gravity, the first planetary axis XP1, and the first carrier axis XCA are aligned in a straight line when viewed from the axial direction X.

[0048] The second balance weight 2M is a mass that rotates in the same direction as the second carrier CB, similar to the relationship between the first balance weight 1M and the first carrier CA. In this embodiment, the second balance weight 2M is a mass that constitutes a part of the second carrier CB. The second balance weight 2M shown in Figures 1 and 3 is an integral structure with the second carrier CB and is a portion that protrudes from the outer circumference of the second carrier CB toward the first axial direction X1. The position and range occupied by the second balance weight 2M on the second carrier CB, as viewed from the axial direction X, are determined in relation to the surrounding structure and so that the center of gravity of the second balance weight 2M is in a position appropriate for reducing primary vibrations.

[0049] The second balance weight 2M is positioned such that its center of gravity and the second planetary axis XP2 are on opposite sides of the second carrier axis XCB when viewed from the axial direction X. In Figure 1, the second balance weight 2M is positioned such that its center of gravity, the second planetary axis XP2, and the second carrier axis XCB are aligned in a straight line when viewed from the axial direction X.

[0050] The counterbalancer 33S is a mass that rotates in the same direction as the counter rotating member 31. With this configuration, at least a portion of the vibration component in the cylinder radial direction H of the primary vibration when the piston member 12 is reciprocating at an intermediate position between the top dead center and the bottom dead center can be canceled out. In detail, the counterbalancer 33S comprises a third balance weight 3S and a fourth balance weight 4S. The third balance weight 3S can cancel out at least a portion of the vibration component in the cylinder radial direction H of the primary vibration generated by the first piston member 12A and the first planetary gear mechanism 21A. The fourth balance weight 4S cancels out at least a portion of the vibration component in the cylinder radial direction H of the primary vibration generated by the second piston member 12B and the second planetary gear mechanism 21B.

[0051] The third balance weight 3S is a mass that rotates in the same direction as the first counter rotating member 31A. In this embodiment, the third balance weight 3S is a mass that rotates together with the wheel 313 provided on the first counter rotating member 31A. The third balance weight 3S shown in Figures 1 and 2 is an integral structure with the wheel 313 provided on the first counter rotating member 31A, and is a portion of the wheel 313 that protrudes from its outer circumference in the first axial direction X1. The position and range occupied by the third balance weight 3S on the wheel 313, as viewed from the axial direction X, are determined in relation to the surrounding structure and so that the center of gravity of the third balance weight 3S is in a position appropriate for reducing primary vibrations.

[0052] The third balance weight 3S is positioned in a location synchronized with the rotation of the first balance weight 1M. More specifically, the third balance weight 3S is positioned such that, in its rotational state, a first inclination angle (not shown) determined by the center of gravity of the third balance weight 3S is the same as a second inclination angle (not shown) determined by the center of gravity of the first balance weight 1M. The first inclination angle is the angle formed by a reference line along the reciprocating direction I passing through the rotation axis of the third balance weight 3S, viewed from the axial direction X, and an inclined line connecting the rotation axis to the center of gravity of the third balance weight 3S. The second inclination angle is the angle formed by a reference line along the reciprocating direction I passing through the rotation axis of the first balance weight 1M and an inclined line connecting the rotation axis to the center of gravity of the first balance weight 1M.

[0053] The fourth balance weight 4S is a mass that rotates in the same direction as the second counter rotating member 31B, similar to the relationship between the third balance weight 3S and the wheel 313 of the first rotating member. In this embodiment, the fourth balance weight 4S is a mass that rotates together with the wheel 313 of the second counter rotating member 31B. The fourth balance weight 4S shown in Figures 1 and 3 is an integral structure with the wheel 313 of the second counter rotating member 31B, and is a portion of the wheel 313 that protrudes from its outer circumference in the first axial direction X1. The position and range occupied by the fourth balance weight 4S on the wheel 313, as viewed from the axial direction X, are determined in relation to the surrounding structure and so that the center of gravity of the fourth balance weight 4S is in a position appropriate for reducing primary vibrations.

[0054] The fourth balance weight 4S is positioned in a location synchronized with the rotation of the second balance weight 2M. More specifically, the fourth balance weight 4S is positioned such that, in the rotational state, the third inclination angle (not shown), determined by the center of gravity of the fourth balance weight 4S, and the fourth inclination angle (not shown), determined by the center of gravity of the second balance weight 2M, are the same. The third inclination angle, similar to the first inclination angle described above, is the angle formed by a reference line along the reciprocating direction I passing through the rotation axis of the third balance weight 3S, viewed from the axial direction X, and an inclined line connecting the rotation axis to the center of gravity of the third balance weight 3S. The fourth inclination angle, similar to the second inclination angle described above, is the angle formed by a reference line along the reciprocating direction I passing through the rotation axis of the second balance weight 2M, and an inclined line connecting the rotation axis to the center of gravity of the second balance weight 2M.

[0055] Torque balancer 33T is either a fifth balance weight 5T or a second load L2, having the same moment of inertia as the first load L1.

[0056] The fifth balance weight 5T (not shown in this embodiment) is a mass provided on the rotating member, similar to the first balance weight 1M, the second balance weight 2M, the third balance weight 3S, and the fourth balance weight 4S. The second load L2, similar to the first load L1, converts rotational motion into a form suitable for the application. The second load L2, similar to the first load L1, can be, for example, a generator or a wheel. In the example shown in Figure 1, the torque balancer 33T is the second load L2.

[0057] The fifth balance weight 5T or the second load L2 rotates in the opposite direction to the output member 4. The fifth balance weight 5T is provided on a rotating member that rotates in the opposite direction to the interlocking gear shaft 41 when the interlocking gear shaft 41 rotates integrally with the output member 4. In this embodiment, such a rotating member could be, for example, the wheel 313, the first interlocked gear 321, and the second interlocked gear 322. Similarly, when the interlocking gear shaft 41 rotates integrally with the output member 4, the second load L2 is driven and connected to a rotating member that rotates in the opposite direction to the interlocking gear shaft 41. In this embodiment, a rotating member driven and connected to the second load L2 could be, for example, the counter shaft 312. In the example shown in Figure 1, the second load L2 is driven and connected to the counter shaft 312 of the first counter rotating member 31A. Preferably, the second load L2 has the same configuration as the first load L1. For example, if the first load L1 is a generator, it is preferable that the second load L2 is also a generator with the same moment of inertia as the first load L1. This configuration makes it possible to efficiently reduce vibrations caused by torque fluctuations in the reciprocating unit 1.

[0058] As described above, the reciprocating internal combustion engine 100 generates secondary vibrations at approximately twice the frequency of the primary vibrations, in addition to primary vibrations and vibrations due to torque fluctuations, due to the reciprocating motion of the piston member 12. Secondary vibrations are more likely to occur when there is a large speed difference between the speed of the piston member 12 moving from top dead center to bottom dead center and the speed of the piston member 12 moving from bottom dead center to top dead center.

[0059] In this embodiment, it is preferable that the pitch circle radius of the ring gear RG is the same as the pitch circle diameter of the planetary gear PG, and that the dimension from the planetary axis XP to the input axis XZ in the crank member 22 in an axial view is the same as the pitch circle radius of the planetary gear PG. With this configuration, the speed difference between the speed of the piston member 12 moving from top dead center to bottom dead center and the speed of the piston member 12 moving from bottom dead center to top dead center can be kept small. Therefore, secondary vibrations generated by the reciprocating internal combustion engine 100 can be reduced.

[0060] [Embodiment 2] The reciprocating internal combustion engine 100 of Embodiment 2 will be described with reference to Figures 4 to 6. The vibration reduction structure 3 of the reciprocating internal combustion engine 100 of Embodiment 2 differs from that of the reciprocating internal combustion engine 100 of Embodiment 1. In the following description, only the differences between the reciprocating internal combustion engine 100 of Embodiment 2 and the reciprocating internal combustion engine 100 of Embodiment 1 will be described. The same configurations of the reciprocating internal combustion engine 100 of Embodiment 2 and that of the reciprocating internal combustion engine 100 of Embodiment 1 will not be described.

[0061] In this embodiment, as shown in Figure 4, the vibration reduction structure 3 includes a counter rotating member 31 which, in addition to the configuration described in Embodiment 1, is equipped with a sub-wheel 314 that rotates in conjunction with the wheel 313. Furthermore, the main balancer 33M is provided on the wheel 313 instead of the carrier C, and the counter balancer 33S is provided on the sub-wheel 314 instead of the wheel 313, which is a difference from Embodiment 1. In addition, this embodiment differs from Embodiment 1 in that the interlocking mechanism 32 does not include an interlocking gear 323, and the first interlocked gear 321 and the second interlocked gear 322 mesh directly with each other.

[0062] The sub-wheel 314 is a rotating body that rotates in the opposite direction to the wheel 313. As shown in Figure 4, the sub-wheel 314 of the first counter rotating member 31A is positioned I1 in the reciprocating direction relative to the wheel 313 of the first counter rotating member 31A. The sub-wheel 314 of the first counter rotating member 31A is equipped with a first linked gear 321 that meshes with an input portion 311, which is an external gear formed on the wheel 313. Similarly, the sub-wheel 314 of the second counter rotating member 31B is positioned I1 in the reciprocating direction relative to the wheel 313 of the second counter rotating member 31B. The sub-wheel 314 of the second counter rotating member 31B is equipped with a second linked gear 322 that meshes with an input portion 311, which is an external gear formed on the wheel 313. With this configuration, the second carrier CB rotates in the opposite direction to the first carrier CA. Therefore, the couple generated by the first piston member 12A and the first power conversion unit 2A can be canceled out by the couple generated by the second piston member 12B and the second power conversion unit 2B. As a result, vibrations generated throughout the reciprocating internal combustion engine 100 can be reduced.

[0063] The first balance weight 1M is mounted on the wheel 313 so as to rotate in a positional relationship with the first planetary gear PGA that is in opposite phase. More specifically, the first balance weight 1M is positioned such that, in the rotating state, the difference between the aforementioned second inclination angle (not shown), which is determined by the center of gravity of the first balance weight 1M, and the fifth inclination angle (not shown), which is determined by the center of gravity of the first planetary gear PGA, is 180°. The second inclination angle is, as described above, the angle formed by a reference line along the reciprocating direction I passing through the rotation axis of the first balance weight 1M, viewed from the axial direction X, and an inclined line connecting the rotation axis to the center of gravity of the first balance weight 1M. The fifth inclination angle is the angle formed by a reference line along the reciprocating direction I passing through the first carrier axis XCA, and an inclined line connecting the first carrier axis XCA to the center of gravity of the first planetary gear PGA. The second balance weight 2M, like the first balance weight 1M, is mounted on the wheel 313 so as to rotate in a positional relationship with the second planetary gear PGB that is in opposite phase.

[0064] In this embodiment, the first linked shaft 32A, which rotatably supports the first linked gear 321 in the case 5, rotates integrally with the output member 4. The first linked gear 321 is driven and connected to the first load L1. On the other hand, the second linked gear 322 is driven and connected to the torque balancer 33T. In the example shown in Figure 4, the torque balancer 33T is driven and connected to the second linked shaft 32B, which rotatably supports the second linked gear 322 in the case 5. The torque balancer 33T is the second load L2. With this configuration, the first load L1 and the second load L2 or the fifth balance weight 5T can be placed close together, making it easier to simplify the overall configuration of the reciprocating internal combustion engine 100.

[0065] [Embodiment 3] The reciprocating internal combustion engine 100 of Embodiment 3 will be described with reference to Figure 7. The reciprocating internal combustion engine 100 of Embodiment 3 differs from the reciprocating internal combustion engine 100 of Embodiment 1 in its interlocking mechanism 32. In the following description, only the differences between the reciprocating internal combustion engine 100 of Embodiment 3 and the reciprocating internal combustion engine 100 of Embodiment 1 will be described. The parts of the reciprocating internal combustion engine 100 of Embodiment 3 that are the same as those of the reciprocating internal combustion engine 100 of Embodiment 1 will not be described.

[0066] In this embodiment, unlike in Embodiment 1, the interlocking mechanism 32 does not have the interlocking gear 323 meshing with the first linked gear 321. In addition to the configuration described in Embodiment 1, the interlocking mechanism 32 includes a speed-increasing gear 324 that meshes with both the first linked gear 321 and the interlocking gear 323. The speed-increasing gear 324 is a gear with a smaller pitch circle diameter than the interlocking gear 323, the first linked gear 321, and the second linked gear 322. In this embodiment, the speed-increasing gear 324 includes a speed-increasing gear shaft 4F that is rotatably supported in the case 5, and the speed-increasing gear shaft 4F rotates integrally with the output member 4. With this configuration, a load requiring a high rotational speed input can be set as the first load L1. In the example shown in Figure 7, the speed-increasing gear 324 is positioned closer to the cylinder 11 in the cylinder radial direction H than to the rotation axis of the counter shaft 312 and the interlocking gear 323 of the first counter rotating member 31A. With this configuration, even when the interlocking mechanism 32 is equipped with a speed-increasing gear 324, the entire reciprocating internal combustion engine 100 can be made more compact.

[0067] Furthermore, in this embodiment, the torque balancer 33T is driven and connected to the interlocking gear shaft 41. In the example shown in Figure 7, the torque balancer 33T is the second load L2. With this configuration, the first load L1 and the second load L2 can be placed close together, making it easier to reduce the space occupied by the reciprocating internal combustion engine 100 and its surrounding structure.

[0068] [Embodiment 4] The reciprocating internal combustion engine 100 of Embodiment 4 will be described with reference to Figures 8 to 10. The reciprocating internal combustion engine 100 of Embodiment 4 differs from the reciprocating internal combustion engine 100 of Embodiment 1 in its interlocking mechanism 32. In the following description, only the differences between the reciprocating internal combustion engine 100 of Embodiment 4 and the reciprocating internal combustion engine 100 of Embodiment 1 will be described. The parts of the reciprocating internal combustion engine 100 of Embodiment 4 that are the same as those of the reciprocating internal combustion engine 100 of Embodiment 1 will not be described.

[0069] In this embodiment, the interlocking mechanism 32 differs from that of Embodiment 1 in that it includes a belt mechanism 325 that circulates along the circulation path, instead of the first interlocked gear 321 and the second interlocked gear 322 described in Embodiment 1. In addition, the interlocking mechanism 32 of Embodiment 3 differs from that of Embodiment 1 in that the interlocking gear 323 engages with the input section 311 of the first counter rotating member 31A.

[0070] The belt mechanism 325 includes an endless belt 32V arranged along a circulation path, a first sprocket 326 rotatably supported by the case 5, and a second sprocket 327 rotatably supported by the case 5. The belt 32V is supported by the first sprocket 326 and the second sprocket 327 respectively so as to circulate along the circulation path in conjunction with the rotation of the first sprocket 326 and the second sprocket 327. In this embodiment, the belt 32V is wrapped around the first sprocket 326 and the second sprocket 327.

[0071] As illustrated in Figure 8, the first sprocket 326 rotates integrally with the counter shaft 312 of the second counter rotating member 31B. More specifically, as shown in Figure 10, the first sprocket 326 has the same rotational axis as the counter shaft 312 and is positioned on the second axial side X2 with respect to the wheel 313. With this configuration, when the counter shaft 312 of the second counter rotating member 31B rotates, the first sprocket 326, which rotates integrally with the counter shaft 312, also rotates, causing the belt 32V to circulate along the circulation path.

[0072] On the other hand, as shown in Figure 8, the second sprocket 327 is positioned closer to the cylinder 11 in the cylinder radial direction H than the counter shaft 312 of the first counter rotating member 31A. The second sprocket 327 rotates together with the interlocking gear 323, which meshes with the input section 311, which is an external gear of the first counter rotating member 31A. Therefore, when the input section 311 rotates, the interlocking gear 323 and the second sprocket 327 also rotate, causing the belt 32V to circulate along the circulation path. With this configuration, even if the first counter rotating member 31A and the second counter rotating member 31B are positioned far apart in the reciprocating direction I, the first counter rotating member 31A and the second counter rotating member 31B can be rotated in conjunction with a simple structure and a small number of parts.

[0073] Furthermore, in this embodiment, the interlocking gear shaft 41 rotates integrally with the output member 4, and a torque balancer 33T is provided on the counter shaft 312 of the first counter rotating member 31A. Specifically, the interlocking gear shaft 41 illustrated in Figure 8 is driven and connected to the first load L1. The torque balancer 33T illustrated in Figures 8 and 9 is a fifth balance weight 5T. The fifth balance weight 5T illustrated in Figure 9 is positioned on the second axial side X2 relative to the input unit 311 and is a disc having the same rotation axis as the counter shaft 312. In the example shown in Figure 9, the fifth balance weight 5T is integrated with the counter shaft 312.

[0074] [Embodiment 5] The reciprocating internal combustion engine 100 of Embodiment 5 will be described with reference to Figures 11 and 12. The reciprocating internal combustion engine 100 of Embodiment 5 differs from the reciprocating internal combustion engine 100 of Embodiment 1 in that the first piston member 12A and the second piston member 12B of the reciprocating unit 1 slide against each other in different cylinders 11. In the following description, only the differences between the reciprocating internal combustion engine 100 of Embodiment 5 and the reciprocating internal combustion engine 100 of Embodiment 1 will be described. The parts of the reciprocating internal combustion engine 100 of Embodiment 5 that are the same as those of the reciprocating internal combustion engine 100 of Embodiment 1 will not be described.

[0075] In this embodiment, the reciprocating unit 1 differs from Embodiment 1 in that the cylinder 11 comprises a first cylinder 111 and a second cylinder 112. Each of the first cylinder 111 and the second cylinder 112 is a bottomed cylindrical wall with a wall surrounding the outer circumference of the combustion chamber and one end of the combustion chamber in the reciprocating direction I. The first piston member 12A forms a combustion chamber by covering the opening of the first cylinder 111 and reciprocates along the longitudinal direction of the first cylinder 111. Similarly, the second piston member 12B forms a combustion chamber by covering the opening of the second cylinder 112 and reciprocates along the longitudinal direction of the second cylinder 112.

[0076] In this embodiment, the first piston member 12A and the second piston member 12B are arranged in a horizontally opposed configuration. More specifically, the first piston member 12A and the second piston member 12B are arranged so that they reciprocate along the same axis. The first cylinder 111 and the first piston member 12A, the first power conversion unit 2A, the second power conversion unit 2B, the second piston member 12B and the second cylinder 112 are arranged along the reciprocating direction I in the order described above.

[0077] In this embodiment, the counter rotating member 31 is positioned adjacent to the power conversion unit 2 in the cylinder radial direction H. In addition, unlike Embodiment 1, the interlocking mechanism 32 does not have an interlocking gear 323, and the first linked gear 321 and the second linked gear 322 are directly meshed. With this configuration, the second carrier CB rotates in the opposite direction to the first carrier CA. Therefore, the couple generated by the first piston member 12A and the first power conversion unit 2A can be canceled out by the couple generated by the second piston member 12B and the second power conversion unit 2B. As a result, vibrations generated throughout the reciprocating internal combustion engine 100 can be reduced. Furthermore, with this configuration, the interlocking mechanism 32 can be constructed without an interlocking gear 323, making it easier to miniaturize the entire reciprocating internal combustion engine 100.

[0078] Preferably, either the counter shaft 312 that rotates with the first linked gear 321 or the counter shaft 312 that rotates with the second linked gear 322 rotates integrally with the output member 4, while the other is driven and connected to the torque balancer 33T. With this configuration, torque fluctuations occurring in the combustion chambers of the first cylinder 111 and the second cylinder 112 can be effectively reduced in a small space. In the example shown in Figure 11, the counter shaft 312 that rotates with the first linked gear 321 rotates integrally with the output member 4. On the other hand, the second load L2 is driven and connected to the counter shaft 312 that rotates with the second linked gear 322.

[0079] [Embodiment 6] The reciprocating internal combustion engine 100 of Embodiment 6 will be described with reference to Figures 13 and 14. The reciprocating internal combustion engine 100 of Embodiment 6 differs from the reciprocating internal combustion engine 100 of Embodiment 5 in the arrangement of the first cylinder 111 and the second cylinder 112. In the following description, only the differences between the reciprocating internal combustion engine 100 of Embodiment 6 and the reciprocating internal combustion engine 100 of Embodiment 5 will be described. The parts of the reciprocating internal combustion engine 100 of Embodiment 6 that are the same as those of the reciprocating internal combustion engine 100 of Embodiment 5 will not be described.

[0080] In this embodiment, the first piston member 12A is positioned adjacent to the second piston member 12B in the cylinder radial direction H. The first piston member 12A and the first cylinder 111 illustrated in Figure 13 are arranged such that the reciprocating trajectory of the first piston member 12A is parallel to the reciprocating trajectory of the second piston member 12B.

[0081] Furthermore, in this embodiment, the first counter rotating member 31A is connected to the second carrier CB so as to rotate integrally with it, and the second counter rotating member 31B is connected to the first carrier CA so as to rotate integrally with it. In the example shown in Figure 13, the second carrier CB also serves as the first counter rotating member 31A, and the first carrier CA also serves as the second counter rotating member 31B. With this configuration, since the counter rotating member 31 constitutes part of the planetary gear mechanism 21, the entire reciprocating internal combustion engine 100 can be easily miniaturized.

[0082] In this embodiment, the interlocking mechanism 32 is configured by the meshing of an output section 21C, which is an external gear on the first carrier CA, and an output section 21C, which is an external gear on the second carrier CB. The number of teeth and pitch circle diameter of the output section 21C on the first carrier CA are set to be the same as the number of teeth and pitch circle diameter of the output section 21C on the second carrier CB. As a result, the first carrier CA rotates at the same speed in the opposite direction to the rotation of the second carrier CB, in conjunction with the rotation of the second carrier CB. With this configuration, the interlocking mechanism 32 also serves as the counter rotating member 31 and constitutes part of the planetary gear mechanism 21, making it easier to miniaturize the entire reciprocating internal combustion engine 100.

[0083] In this embodiment, the output member 4 includes an output gear 421 that meshes with a gear that serves as an output section 21C of the second carrier CB, and an output shaft 422 that rotatably supports the output gear 421 in the case 5. The output gear 421 is positioned in the cylinder radial direction H with respect to the second carrier axis XCB, on the side opposite to the side where the first carrier CA is located. The first load L1 is driven and connected to the output shaft 422.

[0084] Furthermore, in this embodiment, the balancer 33 further includes a torque balance member 43 that rotates in the opposite direction to the output member 4. The torque balance member 43 rotates in conjunction with the first carrier CA. Specifically, the torque balance member 43 includes a torque balance gear 431 that meshes with the gear that serves as the output section 21C of the first carrier CA, and a torque balance shaft 432 that rotatably supports the torque balance gear 431 in the case 5. The torque balance shaft 432 is positioned in the cylinder radial direction H with respect to the first carrier axis XCA, on the side opposite to the side where the second carrier CB is located. The fifth balance weight 5T or the second load L2 rotates together with the torque balance shaft 432. With this configuration, it is easy to realize a structure that reduces vibrations caused by torque fluctuations in the reciprocating unit 1 in a compact structure.

[0085] In the example shown in Figure 14, the torque balancer 33T is the fifth balance weight 5T. The fifth balance weight 5T is positioned at a distance X2 in the axial direction from the torque balance gear 431, which rotates integrally with the torque balance shaft 432. The fifth balance weight 5T has the same rotational axis as the torque balance shaft 432 and rotates integrally with the torque balance shaft 432.

[0086] [Other Embodiments] Next, other embodiments of the reciprocating internal combustion engine 100 will be described.

[0087] (1) In the above embodiment, the reciprocating unit 1 was described as comprising a first piston member 12A and a second piston member 12B. However, the number of piston members 12 may be two or more.

[0088] (2) In the above embodiment, the output unit 21C was described as an external gear. However, the output unit 21C is not limited to an external gear as long as it can output rotational motion. For example, the output unit 21C may be an internal gear, a belt, or a chain.

[0089] (3) In the above embodiment 6, the first piston member 12A and the first cylinder 111 were described as being arranged such that the reciprocating trajectory of the first piston member 12A is parallel to the reciprocating trajectory of the second piston member 12B. However, the first piston member 12A and the first cylinder 111 may also be arranged such that the reciprocating trajectory of the first piston member 12A intersects or intersects with the reciprocating trajectory of the second piston member 12B.

[0090] (4) The configurations disclosed in the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0091] [Summary of this embodiment] The following is a summary of the embodiments relating to the reciprocating internal combustion engine (100) described above.

[0092] The reciprocating internal combustion engine (100) includes a first planetary gear mechanism (21A) comprising a first ring gear (RGA) which is an internal gear, a first carrier (CA) rotatably supported with respect to the first ring gear (RGA), and a first planetary gear (PGA) rotatably supported with respect to the first carrier (CA) and meshing with the first ring gear (RGA); a first crank member (22A) connected to rotate integrally with the first planetary gear (PGA); and the rotation of the first planetary gear (PGA) relative to the first crank member (22A). A first piston member (12A) is connected to a first input axis (XZA) which is set at a position spaced apart from the first planetary axis (XP1), which is the pivot axis, so as to be rotatable relative to it; a first counter rotating member (31A) rotates in the opposite direction to the first carrier (CA) at the same rotational speed in conjunction with the rotation of the first carrier (CA); a second ring gear (RG) which is an internal gear; a second carrier (CB) which is rotatably supported relative to the second ring gear (RG); and a second ring gear (31A) which is rotatably supported relative to the second carrier (CB). A second planetary gear mechanism (21B) comprising a second planetary gear (PGB) meshing with a gear (RG), a second crank member (22B) connected to rotate integrally with the second planetary gear (PGB), a second piston member (12B) connected to the second crank member (22B) so as to be rotatable relative to a second input axis (XZB) set at a position spaced apart from the second planetary axis (XP2), which is the rotation axis of the second planetary gear (PGB), and a second carrier (CB) that rotates in conjunction with the rotation of the second carrier (CB) and in opposition to the second carrier (CB). The system includes a second counter rotating member (31B) that rotates in opposite directions at the same rotational speed, an interlocking mechanism (32) that interlocks the first counter rotating member (31A) and the second counter rotating member (31B) so that they rotate at the same rotational speed, and an output member (4) that rotates in conjunction with the first carrier (CA), the second carrier (CB), the first counter rotating member (31A), the second counter rotating member (31B), and the interlocking mechanism (32).

[0093] With this configuration, the planetary gear mechanism (21), which has less difference in piston speed change between the forward and return strokes compared to a crank mechanism, converts the reciprocating motion of the first piston member (12A) and the second piston member (12B) into rotational motion, making it easier to suppress secondary vibrations. In addition, the primary vibrations caused by the reciprocating motion of the first piston member (12A) and the second piston member (12B) can be effectively reduced by the first counter rotating member (31A) and the second counter rotating member (31B). Therefore, it is easier to reduce vibrations generated from the entire reciprocating internal combustion engine (100).

[0094] Here, the system includes a first balance weight (1M) that rotates in the same direction as the first carrier (CA), a second balance weight (2M) that rotates in the same direction as the second carrier (CB), a third balance weight (3S) that rotates in the same direction as the first counter rotating member (31A), a fourth balance weight (4S) that rotates in the same direction as the second counter rotating member (31B), and a fifth balance weight (5T) or second load (L2) having the same moment of inertia as the first load (L1) connected to the output member (4), wherein the fifth balance weight (5T) or second load (L2) preferably rotates in the opposite direction to the output member (4).

[0095] In this configuration, the first load (L1), first balance weight (1M), second balance weight (2M), third balance weight (3S), fourth balance weight (4S), and fifth balance weight (5T) or second load (L2) reduce primary vibrations and effectively absorb torque fluctuations that occur during the combustion cycle.

[0096] Furthermore, it is preferable that the first rotational axis (XCA), which is the rotational axis of the first carrier (CA), and the second rotational axis (XCB), which is the rotational axis of the second carrier (CB), are arranged parallel to each other, the direction along the first rotational axis (XCA) and the second rotational axis (XCB) is defined as the axial direction (X), and the imaginary line connecting the first rotational axis (XCA) and the second rotational axis (XCB) in an axial view along the axial direction (X) is defined as the reference axis, and that the first piston member (12A) and the second piston member (12B) are arranged in opposite directions to each other so as to reciprocate along the reference axis.

[0097] In this configuration, the first planetary gear (PGA) connected to the first piston member (12A) rotates in the opposite direction to the second planetary gear (PGB) connected to the second piston member (12B). Therefore, vibrations caused by couples occurring throughout the reciprocating internal combustion engine (100) are easily reduced.

[0098] Furthermore, it is preferable that the first rotation axis (XCA), which is the rotation axis of the first carrier (CA), and the second rotation axis (XCB), which is the rotation axis of the second carrier (CB), are arranged parallel to each other, the first counter rotating member (31A) is connected to the second carrier (CB) so as to rotate integrally with it, and the second counter rotating member (31B) is connected to the first carrier (CA) so as to rotate integrally with it.

[0099] In this configuration, the first counter rotating member (31A) is connected to the second carrier (CB) so as to rotate integrally with it, allowing the first counter rotating member (31A) and the second carrier (CB) to be arranged coaxially. Similarly, the second counter rotating member (31B) is connected to the first carrier (CA) so as to rotate integrally with it, allowing the second counter rotating member (31B) and the first carrier (CA) to be arranged coaxially. Therefore, these mechanisms can be easily miniaturized and simplified. [Industrial applicability]

[0100] The technology described herein can be used in reciprocating internal combustion engines. [Explanation of Symbols]

[0101] 1M: First balance weight, 2M: Second balance weight, 3S: Third balance weight, 4: Output member, 4S: Fourth balance weight, 5T: Fifth balance weight, 12A: First piston member, 12B: Second piston member, 21A: First planetary gear mechanism, 21B: Second planetary gear mechanism, 22A: First crank member, 22B: Second crank member, 31A: First counter rotation member, 31B: Second counter rotation member, 32: Interlocking mechanism Structure, 100: Reciprocating internal combustion engine, CA: First carrier, CB: Second carrier, L1: First load, L2: Second load, PGA: First planetary gear, PGB: Second planetary gear, RGA: First ring gear, X: Axial direction, XCA: First rotation axis (first carrier axis), XCB: Second rotation axis (second carrier axis), XP: Planetary axis, XP1: First planetary axis, XP2: Second planetary axis, XZ: Input axis, XZA: First input axis, XZB: Second input axis

Claims

1. A first planetary gear mechanism comprising: a first ring gear which is an internal gear; a first carrier rotatably supported with respect to the first ring gear; and a first planetary gear rotatably supported with respect to the first carrier and meshing with the first ring gear; A first crank member is connected to the first planetary gear so as to rotate integrally with it, A first piston member is connected to the first crank member so as to be able to rotate relative to it around a first input axis which is set at a position spaced apart from the first planetary axis which is the rotation axis of the first planetary gear, A first counter rotating member rotates in the same rotational speed as the first carrier but in the opposite direction to the first carrier, in conjunction with the rotation of the first carrier, A second planetary gear mechanism comprising: a second ring gear which is an internal gear; a second carrier rotatably supported with respect to the second ring gear; and a second planetary gear rotatably supported with respect to the second carrier and meshing with the second ring gear; A second crank member is connected to the second planetary gear so as to rotate integrally with it, A second piston member is connected to the second crank member so as to be able to rotate relative to it around a second input axis which is set at a position spaced apart from the second planetary axis which is the rotation axis of the second planetary gear, A second counter rotating member rotates in the same direction as the second carrier but at the same rotational speed, in conjunction with the rotation of the second carrier, An interlocking mechanism that links the first counter rotating member and the second counter rotating member so that they rotate at the same rotational speed, A reciprocating internal combustion engine comprising the first carrier, the second carrier, the first counter rotating member, the second counter rotating member, and an output member that rotates in conjunction with the interlocking mechanism.

2. A first balance weight that rotates in the same direction as the first carrier, A second balance weight that rotates in the same direction as the second carrier, A third balance weight that rotates in the same direction as the first counter rotating member, A fourth balance weight that rotates in the same direction as the second counter rotating member, The output member is connected to a fifth balance weight or second load having the same moment of inertia as the first load, The reciprocating internal combustion engine according to claim 1, wherein the fifth balance weight or the second load rotates in the opposite direction to the output member.

3. The first rotation axis, which is the rotation axis of the first carrier, and the second rotation axis, which is the rotation axis of the second carrier, are arranged parallel to each other. The direction along the first and second rotational axes is defined as the axial direction, and the imaginary line connecting the first and second rotational axes in an axial view along the axial direction is defined as the reference axis. The reciprocating internal combustion engine according to claim 1 or 2, wherein the first piston member and the second piston member are arranged in opposite directions to each other so as to reciprocate on the reference axis.

4. The first rotation axis, which is the rotation axis of the first carrier, and the second rotation axis, which is the rotation axis of the second carrier, are arranged parallel to each other. The first counter rotating member is connected to the second carrier so as to rotate integrally with it. The reciprocating internal combustion engine according to claim 1 or 2, wherein the second counter rotating member is connected to the first carrier so as to rotate integrally with it.

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