JP6295592B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine provided with a primary balancer that suppresses vibration in a primary mode caused by a crankshaft and a secondary balancer that suppresses vibration in a secondary mode.

  In an internal combustion engine in which at least two pistons are connected to one crankshaft, one primary eccentric balance shaft (primary balancer) and two secondary eccentric balance shafts (secondary balancer) are respectively connected to the crankshaft. Patent Document 1 discloses an internal combustion engine arranged in parallel to the above. In this internal combustion engine, the primary eccentric balance shaft is rotated at the same rotational speed as the crankshaft by the power transmitted from the crankshaft, and the two secondary eccentric balance shafts are driven by the power transmitted from the crankshaft. Rotate in opposite directions at a rotational speed twice that of the crankshaft.

  According to the internal combustion engine described in Patent Document 1, of the two secondary eccentric balance shafts, the first secondary eccentric balance shaft is used so as to coincide with the axis of the primary eccentric balance shaft. By penetrating the eccentric balance shaft, the weight is reduced and the bulk is not increased. The rotation direction of the first secondary eccentric balance shaft built in the primary eccentric balance shaft is set to the same direction as the rotation direction of the primary eccentric balance shaft. As a result, the rotational speed difference between the primary eccentric balance shaft and the first secondary eccentric balance shaft is reduced to reduce risks such as wear and rotational resistance.

  In order to drive the primary eccentric balance shaft and the secondary eccentric balance shaft, some kind of power transmission mechanism is required. These power transmission mechanisms must be able to accurately observe the rotation angle and rotation speed of the primary eccentric balance shaft and the secondary eccentric balance shaft with respect to the crankshaft. Therefore, in patent document 1, motive power is each transmitted by the gear mechanism. The primary eccentric balance shaft is connected to the crankshaft by a constant speed gear mechanism, and the first secondary eccentric balance shaft is connected to the crankshaft by a double speed gear mechanism. In contrast to the gear mechanism that connects the primary eccentric balance shaft to the crankshaft, the gear mechanism that connects the first secondary eccentric balance shaft to the crankshaft is located at the opposite end of the crankshaft. Has been placed.

JP 2011-102602 A

  By the way, an internal combustion engine with a small number of cylinders is desired to be small, light, and inexpensive, and providing a balancer to suppress vibration goes against these. In particular, Patent Document 1 includes both a primary eccentric balance shaft and a secondary eccentric balance shaft, and the number of shafts is reduced by incorporating one of the secondary eccentric balance shafts into the primary eccentric balance shaft. . However, if the gear mechanisms for driving these are arranged at both ends of the crankshaft, a cover for protecting the gear mechanism and the like are attached to each, so that the total length of the engine becomes longer in the axial direction of the crankshaft. In Patent Document 1, it is suggested to concentrate on one side, but it does not describe how to do it specifically, such as superiority over the case where it is arranged on both sides.

  Accordingly, the present invention provides an internal combustion engine that has a small occupied volume for providing a primary balancer and a secondary balancer and can be manufactured at low cost.

  An internal combustion engine according to the present invention includes a crankshaft, a primary balancer, a first secondary balancer, a second secondary balancer, a primary gear mechanism, and a secondary gear mechanism. The primary balancer has a primary weight in which a rotary shaft is disposed in parallel to the rotary shaft of the crankshaft and the center of gravity is displaced with respect to the rotary shaft. The first secondary balancer has a secondary weight that is inserted into the primary balancer and has a rotational axis that is coaxial with the rotational axis of the primary balancer and whose center of gravity is displaced with respect to the rotational axis. The second secondary balancer has a secondary weight in which a rotation axis is arranged in parallel with the rotation axis of the first secondary balancer and the center of gravity is displaced with respect to the rotation axis. The primary gear mechanism includes a primary drive gear and a primary driven gear. The primary drive gear is provided at one end of the crankshaft. The primary driven gear is provided in the primary balancer and meshes with the primary drive gear. The primary gear mechanism rotates the primary balancer in the opposite direction to the crankshaft at the same rotational speed. The secondary gear mechanism includes a secondary drive gear, a first secondary driven gear, and a second secondary driven gear. The secondary drive gear is provided further on the front end side of the primary drive gear at one end of the crankshaft. The first secondary driven gear is provided in the first secondary balancer and meshes with the secondary drive gear. The second secondary driven gear is provided in the second secondary balancer and meshes with the first secondary driven gear. Then, the secondary gear mechanism rotates the first secondary balancer and the second secondary balancer in directions opposite to each other at twice the rotational speed of the crankshaft.

In the internal combustion engine having the above-described configuration, the secondary weight of the first secondary balancer and the secondary weight of the second secondary balancer are arranged on the secondary gear mechanism side of the primary weight . Further, the end portion of the first secondary balancer opposite to the first secondary driven gear is supported via a bearing provided at a position overlapping the primary weight inside the primary balancer .

  According to the internal combustion engine of the present invention, the primary gear mechanism and the secondary gear mechanism are arranged together at one end portion of the crankshaft. The primary balancer, the first secondary balancer, and the second secondary balancer are the five gears of the primary drive gear, the primary driven gear, the secondary drive gear, the first secondary driven gear, and the second secondary driven gear. Are driven. The primary drive gear and the secondary drive gear, and the primary driven gear and the first secondary driven gear are arranged so as to overlap each other. There may be only one cover covering the primary gear mechanism and the secondary gear mechanism. The supply of lubricating oil to the primary balancer and the secondary balancer is concentrated on one side, and the structure is simplified. Also, since maintenance can be performed from one side, it is excellent in workability. Furthermore, since the size of the internal combustion engine can be reduced in the direction along the rotation axis of the crankshaft, the degree of freedom of layout in the engine room is increased in a vehicle equipped with this internal combustion engine.

  Further, according to the internal combustion engine of the invention in which the secondary weight of the first secondary balancer and the secondary weight of the second secondary balancer are arranged on the secondary gear mechanism side, the secondary gear mechanism to which drive torque is input Since the secondary weights are close to each other, twisting hardly occurs when the rotational speeds of the first secondary balancer and the second secondary balancer change. According to the internal combustion engine of the invention in which the weight of the first secondary balancer is inserted into the shaft of the primary balancer, secondary vibration can be effectively suppressed.

1 is a cross-sectional view of a vibration damping device for an internal combustion engine according to a first embodiment of the present invention. Sectional drawing of the damping device of the internal combustion engine of 2nd Embodiment which concerns on this invention.

  An internal combustion engine 1 according to a first embodiment of the present invention will be described with reference to FIG. The internal combustion engine 1 is a two-cylinder four-cycle engine, and is equipped with a primary balancer 10 and a secondary balancer 20 as vibration damping devices. The internal combustion engine 1 includes a crankshaft 30, a primary balancer 10, a secondary balancer 20, a primary gear mechanism 40, and a secondary gear mechanism 50.

  The crankshaft 30 has two pistons connected by connecting rods 31 at the same rotational angle position. The crankshaft 30 has a counterweight 32 at a position 180 ° symmetrical to a portion where a piston is connected by a connecting rod 31.

  The primary balancer 10 cooperates with the counterweight 32 of the crankshaft 30 to cancel the excitation force (primary vibration) due to the reciprocating motion of the piston and counterweight 32 of the crankshaft 30 in a direction crossing the direction in which the piston reciprocates. Is provided to cancel out the vibration caused by. The primary balancer 10 has a rotary shaft 10A disposed in parallel to the rotary shaft 30A of the crankshaft 30, and includes a primary weight 11 whose center of gravity is displaced (eccentric) with respect to the rotary shaft 10A. Both ends of the primary balancer 10 pass through the crankcase 6 and are supported by bearings 101 and 102, respectively. The bearings 101 and 102 may be sliding bearings or rolling bearings. As shown in FIG. 1, the primary balancer 10 has a hollow shaft 12 over its entire length.

  The secondary balancer 20 is provided as a set of two, a first secondary balancer 21 and a second secondary balancer 22, in order to cancel the remaining secondary vibration as vibration in the direction in which the piston reciprocates. Is provided. As shown in FIG. 1, the first secondary balancer 21 is inserted into the shaft 12 of the primary balancer 10 that is hollow. The first secondary balancer 21 has a rotation shaft 21A disposed coaxially with the rotation shaft 10A of the primary balancer 10, and a secondary weight whose center of gravity is displaced (eccentric) with respect to the rotation shaft 21A. 211. The second secondary balancer 22 has a rotary shaft 22A disposed in parallel to the rotary shaft 21A of the first secondary balancer 21, and the position of the center of gravity is displaced (eccentric) with respect to the rotary shaft 22A. A secondary weight 221 is included.

  The mass and the eccentricity of the secondary weight 211 of the first secondary balancer 21 and the secondary weight 221 of the second secondary balancer 22 are set so as to generate the same vibration force. In the first embodiment, the secondary weight 211 of the first secondary balancer 21 and the secondary weight 221 of the second secondary balancer 22 are secondary gears in directions along the respective rotation shafts 21A and 22A. It is arranged to be biased toward the mechanism 50 side. Therefore, as shown in FIG. 1, in the internal combustion engine 1 of the present embodiment, the center of gravity of each of the secondary weights 211 and 221 of the first secondary balancer 21 and the second secondary balancer 22 is inside the crankcase 6. Is arranged. Since the center of gravity of the secondary weights 211 and 221 is inside the crankcase 6, the efficiency of suppressing secondary vibration is good.

  The primary gear mechanism 40 transmits power for rotating the primary balancer 10 in the opposite direction to the crankshaft 30 at the same rotational speed as the rotational speed of the crankshaft 30. The primary gear mechanism 40 includes a primary drive gear 41 and a primary driven gear 42. The primary drive gear 41 is provided at a first end 33 that is one end of the crankshaft 30 protruding from the crankcase 6. The primary driven gear 42 is attached to the end of the primary balancer 10 protruding from the crankcase 6 and meshes with the primary drive gear 41. The primary balancer 10 is connected to the crankshaft 30 via the primary gear mechanism 40 so that the primary weight 11 is positioned in phase with the counterweight 32 at the top dead center and the bottom dead center of the piston.

  The secondary gear mechanism 50 transmits power for rotating the first secondary balancer 21 and the second secondary balancer 22 in directions opposite to each other at twice the rotational speed of the crankshaft 30. The secondary gear mechanism 50 includes a secondary drive gear 51, a first secondary driven gear 512, and a second secondary driven gear 522. The secondary drive gear 51 is disposed so as to overlap the primary drive gear 41 in the axial direction of the crankshaft 30, and is provided at the first end 33 which is one end of the crankshaft 30 on the further distal side of the primary drive gear 41. It has been.

  The first secondary driven gear 512 is attached to the end of the first secondary balancer 21 that protrudes from the end of the primary balancer 10 along the rotation axis 21A, and is disposed so as to overlap the primary driven gear 42. The first secondary driven gear 512 is meshed with the secondary drive gear 51. Therefore, the first secondary balancer 21 rotates in the direction opposite to the rotation direction of the crankshaft 30, that is, in the same rotation direction as the primary balancer 10.

  The second secondary driven gear 522 is provided in the second secondary balancer 22 and meshes with the first secondary driven gear 512. Therefore, the second secondary balancer 22 rotates in the direction opposite to the rotation direction of the first secondary balancer 21 and the primary balancer 10, that is, the same direction as the rotation direction of the crankshaft 30.

  The first secondary balancer 21 is located at a position where the primary driven gear 42 is attached and at an intermediate position of the shaft 12 in the direction along the rotary shaft 10A, and is provided inside the primary balancer 10 via bearings 214 and 218. It is supported. The secondary weight 221 of the second secondary balancer 22 arranged in parallel to the first secondary balancer 21 is arranged in the crankcase 6, and the first secondary balancer 21 is connected to the primary balancer 10. The crankcase 6 is supported via bearings 224 and 228 so as to correspond to the positions supported inside.

  The secondary weight 211 of the first secondary balancer 21 and the secondary weight 221 of the second secondary balancer 22 are the primary weight 32 of the crankshaft 30 and the primary weight of the primary balancer 10 when the piston is at top dead center. 11 is connected by the secondary gear mechanism 50 so as to be located at the same position as the rotation angle at which 11 is located, that is, in the direction opposite to the piston. Since the first secondary balancer 21 and the second secondary balancer 22 rotate at twice the rotational speed of the crankshaft 30 and the primary balancer 10, the secondary weights 211, 221 Even when it is at the dead center, it is in the same rotational position as when the piston is at the top dead center.

  In the internal combustion engine 1 configured as described above, when the crankshaft 30 rotates, the primary balancer 10 rotates at the same rotational speed in the rotation direction opposite to that of the crankshaft 30. Further, the first secondary balancer 21 rotates in the same rotational direction as the primary balancer 10 at a double speed. Although the first secondary balancer 21 is inserted in the primary balancer 10, it rotates in the same direction as the primary balancer 10. Therefore, the rotational resistance of the first secondary balancer 21 is Can be kept small. The second secondary balancer 22 rotates at the same speed in the rotation direction opposite to that of the first secondary balancer 21. As a result, the primary vibration and the secondary vibration of the internal combustion engine 1 are suppressed.

  In general, when power is transmitted between two rotating shafts by a gear mechanism, two of a driving gear and a driven gear are required. Therefore, when power is to be transmitted to the primary balancer 10, the first secondary balancer 21, and the second secondary balancer 22, between the crankshaft 30 and the primary balancer 10, the crankshaft 30 Two gears are required between the first secondary balancer 21 and between the first secondary balancer 21 and the second secondary balancer 22, for a total of six gears.

  On the other hand, in this embodiment, the crankshaft 30 and the primary balancer 10 are linked by the primary gear mechanism 40. The primary gear mechanism 40 is composed of two gears, a primary drive gear 41 attached to the crankshaft 30 and a primary driven gear 42 attached to the primary balancer 10, which are arranged on the same plane and mesh with each other. Yes.

  Further, a secondary gear mechanism 50 cooperates between the crankshaft 30 and the first secondary balancer 21 and between the first secondary balancer 21 and the second secondary balancer 22. The secondary gear mechanism 50 is provided on the secondary drive gear 51 attached to the crankshaft 30, the first secondary driven gear 512 provided on the first secondary balancer 21, and the second secondary balancer 22. The second secondary driven gear 522 is arranged on the same plane and meshes with each other in series.

  That is, the internal combustion engine 1 is driven by five gears in order to obtain the driving force from the crankshaft 30 and rotate the primary balancer 10, the first secondary balancer 21, and the second secondary balancer 22. Is being communicated. The primary gear mechanism 40 and the secondary gear mechanism 50 are disposed so as to overlap the crankshaft 30 on the same first end portion 33 side. Not only are all the gears arranged together on one side in the axial direction of the crankshaft 30, but the total number thereof is also small. That is, the secondary gear mechanism 50 has a small size in the direction along the rotation shafts 21A and 22A. Therefore, even when covers are attached to the primary gear mechanism 40 and the secondary gear mechanism 50, the dimensions of the internal combustion engine 1 are reduced in the direction along the rotation axis 30A of the crankshaft 30. Since the volume required to equip both the primary balancer 10 and the secondary balancer 20 is reduced, the bulk of the internal combustion engine 1 is also reduced.

  An internal combustion engine 1 according to a second embodiment of the present invention will be described with reference to FIG. In the configuration of the second embodiment, the same configuration as the configuration of the first embodiment is denoted by the same reference numeral in FIG. 2, and the detailed description thereof refers to the description of the first embodiment. In the internal combustion engine 1 of the second embodiment, the secondary of the first secondary balancer 21 and the second secondary balancer 22 is provided outside the crankcase 6 on the side opposite to the side where the secondary gear mechanism 50 is disposed. Weights 211 and 221 are arranged.

  As shown in FIG. 2, the primary balancer 10 is hollow over the entire length, and a primary driven gear 42 is attached to a first end 33 that is one end protruding from the crankcase 6. The first secondary balancer 21 in which the rotary shaft 21A is arranged coaxially with the rotary shaft 10A of the primary balancer 10 is a part of the primary balancer 10 that penetrates the crankcase 6 from the side where the primary driven gear 42 is attached to the opposite side. The first rod 219 is passed through. The first rod 219 connects the first secondary driven gear 512 and the secondary weight 211 of the first secondary balancer 21. The second secondary balancer 22 in which the rotary shaft 22A is arranged in parallel to the rotary shaft 21A of the first secondary balancer 21 passes through the crankcase 6 from the side where the secondary gear mechanism 50 is arranged to the opposite side. The second secondary driven gear 522 and the secondary weight 221 are connected to each other with a second rod 229. The first secondary balancer 21 and the second secondary balancer 22 are provided with secondary weights at the tips of rods 219 and 229 that protrude outside the crankcase 6 on the side opposite to the side where the secondary gear mechanism 50 is disposed. 211 and 221 are attached.

  According to the internal combustion engine configured as described above, the primary gear mechanism 40 and the secondary gear mechanism 50 are arranged in an overlapping manner, so that the assembling work is simplified. The first secondary balancer 21 and the second secondary balancer 22 pass through the crankcase 6, and both ends of the rods 219 and 229 are supported by bearings 214 and 224. The primary balancer 10, the first secondary balancer 21, and the second secondary balancer 22 are less likely to run out when they rotate, and are easy to stabilize. The first secondary balancer 21 and the second secondary balancer 22 that rotate at twice the speed relative to the crankshaft 30 and the primary balancer 10 have the secondary weights 211 and 221 placed outside the crankcase 6. As in the case of the first embodiment, the weight of the secondary weight can be easily adjusted even after assembly.

  In each drawing of each embodiment, the primary balancer 10 and the secondary balancer 20 (the first secondary balancer 21 and the second secondary balancer 22) are arranged in parallel in one direction with respect to the crankshaft 30. However, the layout of the primary balancer and the secondary balancer 20 with respect to the crankshaft 30 is not limited to the arrangement shown in the drawings.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 10 ... Primary balancer, 10A ... Rotary shaft of (primary balancer), 12 ... Shaft (of primary balancer), 20 ... Secondary balancer, 21 ... First secondary balancer, 21A ... (first Rotating shaft 211 (secondary balancer) 211 ... secondary weight 22 ... secondary secondary balancer 22A ... rotating shaft (second secondary balancer) 221 ... secondary weight 30 ... crankshaft 30A ... Rotating shaft (of crankshaft), 40 ... primary gear mechanism, 41 ... primary drive gear, 42 ... primary driven gear, 50 ... secondary gear mechanism, 51 ... secondary drive gear, 512 ... first secondary driven gear, 522 ... Second secondary driven gear.

Claims (2)

A crankshaft,
A primary balancer having a primary weight with a rotational axis disposed parallel to the rotational axis of the crankshaft and having a center of gravity displaced with respect to the rotational axis;
A first secondary balancer having a secondary weight inserted into the primary balancer and having a rotational axis disposed coaxially with the rotational axis of the primary balancer and having a center of gravity displaced with respect to the rotational axis;
A second secondary balancer having a secondary weight with a rotational axis disposed parallel to the rotational axis of the first secondary balancer and having a center of gravity displaced with respect to the rotational axis;
A primary drive gear provided at one end of the crankshaft, and a primary driven gear provided in the primary balancer and meshing with the primary drive gear, the primary drive gear at the same rotational speed in the opposite direction to the crankshaft. A primary gear mechanism that rotates the balancer;
A secondary drive gear provided at a further front end side of the primary drive gear at one end of the crankshaft, and a first secondary driven gear provided at the first secondary balancer and meshing with the secondary drive gear. And a second secondary driven gear that is provided in the second secondary balancer and meshes with the first secondary driven gear, and the first secondary gear is at a speed twice the rotational speed of the crankshaft. a secondary gear mechanism that rotates the next balancer and the second secondary balancer in opposite directions, the Bei example,
The internal combustion engine characterized in that the secondary weight of the first secondary balancer and the secondary weight of the second secondary balancer are arranged closer to the secondary gear mechanism than the primary weight. organ. An end portion of the first secondary balancer opposite to the first secondary driven gear is supported via a bearing provided in a position overlapping the primary weight inside the primary balancer. The internal combustion engine according to claim 1, wherein:

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