JP6695622B2 - Internal combustion engine - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an internal combustion engine including a mechanism for suppressing vibration caused by a pestle movement.

  2. Description of the Related Art There is known an internal combustion engine equipped with a balance shaft that rotates at a constant speed and in the opposite direction to the crankshaft in order to suppress the rubbing motion that occurs in the crankshaft of an inline 3-cylinder engine or the like (see, for example, Patent Document 1).

  In the internal combustion engine described in Patent Document 1, a balance weight is provided at a position on the balance shaft corresponding to the first cylinder and the third cylinder, thereby canceling out the inertia couple generated by the counterweight of the crankshaft and suppressing the rubbing movement. is doing. In other words, the balance shaft has substantially the same length as the crankshaft, and balance weights are provided at both front and rear ends thereof.

  In this way, the balance shaft, which is long and thick, and has balance weights at multiple points in the front-rear direction, presses the volume of the oil pan at the bottom of the crankcase and reduces the amount of lubricating oil stored in the oil pan. End up.

  The problems described above are not limited to the in-line 3-cylinder internal combustion engine, but exist in general internal-combustion engines such as V-type 6-cylinders and in-line 5-cylinders having a configuration in which the scoring movement of the crankshaft can occur.

JP 54-28914A

  The present invention has been made in view of the above points, and an object thereof is to alleviate the pressure of the volume of the oil pan by the balance shaft while suppressing the rubbing movement of the crankshaft.

In order to solve the above problems, the internal combustion engine according to the present invention has the configuration described below. That is, the internal combustion engine according to the present invention has a balance shaft shorter than the crankshaft, in which the gear provided on the front end side meshes with the gear provided on the front end side of the crankshaft and rotates at the same speed and in the opposite direction as the crankshaft. An internal combustion engine provided with a drive plate or a flywheel at the rear end of the crankshaft, or an eccentric mass provided at the rear end of the crankshaft itself or behind the center of the crankshaft in the extending direction, or the crankshaft. Among the counterweights provided on the rear side, the one located rearward of the center in the extending direction of the crankshaft is heavier than the other counterweights, and the balance shaft serves as the input shaft of the oil pump and the front end side of the balance shaft. , Or an eccentric mass is provided in front of the center of the balance shaft in the extending direction of the balance shaft as a weight for suppressing the rubbing movement of the crankshaft, and the main body of the oil pump is connected to the rear end of the balance shaft. The main body of the pump and the balance shaft are located in front of the central portion of the internal combustion engine in the front-rear direction .

  ADVANTAGE OF THE INVENTION According to this invention, the compression of the volume of the oil pan by a balance shaft can be relieved, suppressing the grind movement of the crankshaft in an internal combustion engine.

The schematic diagram showing the internal-combustion engine concerning one embodiment of this embodiment. The figure for demonstrating the groin motion which generate | occur | produces with the internal combustion engine of this invention. The figure for demonstrating the groining motion which generate | occur | produces in a general internal combustion engine.

  One embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

  The internal combustion engine 0 of the present invention has three in-line cylinders, three cylinders 1, an intake passage (not shown) for supplying intake air into the cylinder 1, and an exhaust gas (not shown) for discharging exhaust gas from the cylinder 1. An exhaust passage, a crankshaft 2 driven by a piston (not shown) arranged in the cylinder 1 and provided with a crank gear 3 at a front end, and an oil pump 5 driven by the crank gear 3 are provided. . The three cylinders 1 are arranged in the front-rear direction of the internal combustion engine 0, that is, in the Y-axis direction in FIG. Further, the crankshaft 2 extends in the Y-axis direction in FIG.

  The crankshaft 2 is located between four crank journals 2a arranged in the Y-axis direction in FIG. 1 and adjacent crank journals 2a, and is connected to a piston in the cylinder 1 via a piston rod (not shown). Three crank pins 2b, a crank arm 2c connecting the crank journal 2a and the crank pin 2b, respectively, and a counter weight 2d extending from the base end of the crank arm 2c to the opposite side of the crank pin 2b. It has and. Each crank pin 2b is provided so as to be shifted by 120 ° around the Y axis. A drive plate 7 is connected to the rear end of the crankshaft 2. The drive plate 7 has a weight fixed to the crankshaft 2 at a position eccentric to the rotation center of the crankshaft 2, that is, a position eccentric from the central axis of the crank journal 2a (a position eccentric from the Y axis). A first eccentric mass 8 is fixed to. That is, the first eccentric mass 8 is arranged rearward of the central portion of the internal combustion engine body (hereinafter, referred to as the central portion in the front-rear direction of the internal combustion engine 0) in which the cylinder block, the cylinder head, and the crankcase are integrated. ing.

  The oil pump 5 meshes with an oil pump body 5a having an input shaft 6 for receiving power transmission, and a crank gear 3 provided at a front end portion of the input shaft 6 so that power is input from the crank gear 4. An oil pump gear 4 that transmits to the shaft 6 is provided. The input shaft 6 extends in the Y-axis direction in FIG. 1, and the total length of the input shaft 6 is shorter than the total length of the crankshaft 2. A second eccentric mass 9 is fixed to the oil pump gear 4 at a position eccentric from the center of rotation. That is, the second eccentric mass 9 is arranged in front of the central portion of the internal combustion engine 0 in the front-rear direction.

  Here, a crankshaft of a general in-line three-cylinder internal combustion engine performs a rubbing motion based on the principle described below with reference to FIG. That is, as shown in FIG. 3, the direction in which the crankshaft extends is the Y-axis direction, the direction from the crankshaft to the cylinder is the Z-axis direction, and the direction from the crankshaft to the cylinder is the Z-axis direction and the Y-axis direction and the Z-axis direction. When the crankshaft rotates when the direction of the arrow is the X-axis direction, the Z-axis component of the force generated in the crankpin becomes unbalanced, and pitch vibration occurs. This pitch vibration still occurs although the Z-axis component of the force generated in the crank weight is offset and reduced by the provision of the crank weight, and the crank weight also generates the X-axis component force. Since the force of the X-axis component acts in opposite directions in the first cylinder and the third cylinder in which the forces are generated, respectively, a couple in the X-axis direction is generated on the crankshaft, and yaw vibration occurs in the internal combustion engine 0. Occurs. When the yaw vibration and the pitch vibration occur, the internal combustion engine 0 equipped with such a crankshaft undergoes a rubbing motion, and the internal combustion engine 0 and the power split mechanism 10 vibrate.

  On the other hand, when the crankshaft 2 rotates in the internal combustion engine of the present embodiment, the crankshaft 2 tries to rub through the principle as described above with reference to FIG. This pestle movement is counteracted. That is, as shown in FIG. 2, the weight (first eccentric mass 8) is fixed at a position rearward of the central portion of the internal combustion engine 0 in the front-rear direction, more specifically, at a position eccentric from the rotation center of the drive plate 7. Therefore, the position where the amplitude is minimized in the crankshaft 2 that performs the rubbing motion, in other words, the node N of the rubbing motion is located behind the center C in the front-rear direction of the internal combustion engine 0. Become. Here, the center C in the front-rear direction of the internal combustion engine 0 is the center of the internal combustion engine body in which the cylinder block, the cylinder head, and the crankcase are integrated. On the other hand, the oil pump gear 4 and the input shaft 6 of the oil pump 5 rotate at the same rotational speed as the crankshaft 2 and in the opposite direction, and more forward than the center C of the internal combustion engine 0 in the front-rear direction, more specifically. Since the weight (second eccentric mass 9) is fixedly provided at a position eccentric from the rotation center axis of the oil pump gear 4, the crankshaft 2 rubs by the movement of the center of gravity of the second eccentric mass 9. As a result, the action given to each part of the internal combustion engine 0 is canceled. That is, the input shaft 6 of the oil pump 5 has a function as a balance shaft for canceling out the rubbing movement of the crankshaft 2.

  As described above, in the internal combustion engine 0 of the present embodiment, the oil pump gear 4 provided on the front end side of the input shaft 6 of the oil pump 5 meshes with the crank gear 3 provided on the front end side of the crankshaft 2, If it is assumed that the input shaft 6 of the oil pump 5, which is a balance shaft shorter than the crankshaft 2, rotates at the same speed as the crankshaft 2 and in the opposite direction, and there is no shaft that functions as a balance shaft, The first eccentric mass 8 is fixed to the drive plate 7 so that the node N of the generated rubbing motion is located behind the center C in the front-rear direction of the internal combustion engine 0, and the rubbing motion of the crankshaft 2 is performed. The second eccentric mass 9 is fixed to the input shaft 6 of the oil pump 5 in order to suppress the above. As a result, the following effects can be obtained. Specifically, the input shaft 6 of the oil pump 5 functioning as a balance shaft is shorter and the crankshaft 2 is shorter than that of a conventional internal combustion engine in which a balance shaft having substantially the same length as the crankshaft 2 is provided. Since the node of the rubbing motion that occurs in the rear is behind the central portion in the front-rear direction of the internal combustion engine 0, only one second eccentric mass 9 for suppressing the rubbing motion of the crankshaft 2 is provided on the front side. Since the grooving movement of the crankshaft 2 can be suppressed by providing it, the space for providing the balance shaft can be saved. Therefore, it is possible to reduce the compression of the volume of the oil pan by the balance shaft while suppressing the grooving movement of the crankshaft 2 in the internal combustion engine 0.

  Further, in the present embodiment, the input shaft 6 of the oil pump 5 is made to function as a balance shaft without providing a special balance shaft. Therefore, unlike the conventional internal combustion engine, the crankshaft 2 is different from other auxiliary machines. In addition, the structure can be simplified and the number of parts can be reduced as compared with the structure in which the rotational driving force is also supplied to the balance shaft.

  The present invention is not limited to the embodiment described above.

  For example, although the first eccentric mass fixed to the drive plate is adopted as the “weight fixedly provided to the crankshaft” in the above-described embodiment, the first eccentric mass fixed to the drive plate is used. Of course, an eccentric mass fixed to the wheel may be adopted, or an eccentric mass fixed to the rear end portion of the crankshaft itself, or at least behind the center of the crankshaft in the extending direction may be adopted. Further, among the counterweights provided on the crankshaft for balancing with the crank arm and the crankpin, the one located rearward of the center in the extending direction of the crankshaft may be heavier than the other counterweights.

  On the other hand, although the second eccentric mass fixed to the oil pump gear is adopted as the “weight fixedly provided to the balance shaft” in the above-described embodiment, the second eccentric mass fixed to the oil pump gear is used in the extending direction of the input shaft itself of the oil pump. Of course, an eccentric mass fixed forward from the center may be adopted.

  In addition, instead of making the input shaft of the oil pump function as a balance shaft, a balance shaft shorter than the crankshaft and rotating at the same speed as the crankshaft but in opposite directions is provided separately from the input shaft of the oil pump. It is also possible to adopt a mode in which the weight is fixed to the balance shaft so that the node of the rubbing motion performed by the balance shaft is located in front of the center in the extending direction of the balance shaft.

  Then, the present invention is applied not only to the in-line 3-cylinder internal combustion engine but also to all the internal-combustion engines having a configuration in which the crankshaft can generate the rubbing motion, such as the V-type 6-cylinder internal combustion engine and the in-line 5-cylinder internal combustion engine. You may.

  In addition, various modifications may be made without departing from the spirit of the present invention.

0 ... Internal combustion engine 2 ... Crank shaft 3 ... Gear provided on the front end side of the crank shaft (crank gear)
4 ... Gear provided on the front end side of the balance shaft (oil pump gear)
6 ... Balance shaft (oil pump input shaft)
8 ... Weight (first eccentric mass)
9 ... Weight (second eccentric mass)

Claims (1)

An internal combustion engine having a balance shaft shorter than a crankshaft, in which a gear provided on a front end side meshes with a gear provided on a front end side of a crankshaft and rotates at the same speed as the crankshaft and in a reverse direction,
The drive plate or flywheel at the rear end of the crankshaft, or the eccentric mass behind the rear end of the crankshaft itself or the center of the crankshaft in the extending direction, or the counterweight provided on the crankshaft The one located behind the center in the extending direction of the shaft is heavier than other counterweights,
The balance shaft serves as the input shaft of the oil pump, and a gear on the front end side of the balance shaft, or in front of the center of the balance shaft in the extending direction , is provided with an eccentric mass as a weight for suppressing the stepping motion of the crankshaft ,
An internal combustion engine in which the main body of the oil pump is connected to the rear end portion of the balance shaft, and the main body of the oil pump and the balance shaft are located in front of the central portion in the front-rear direction of the internal combustion engine.

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