JP2005105819A - Scotch yoke type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Scotch yoke type engine without requiring excessive rigidity for a crankshaft and a cylinder block, while contributing to miniaturization of the engine. <P>SOLUTION: This engine 1 is the Scotch yoke type engine having a yoke 2 for installing pistons 15 to 18. The yoke 2 has a counterweight 23 for restraining vibration caused by the movement of the yoke 2, and balancers 30 and 40 are installed on the yoke 2. The balancers 30 and 40 are respectively arranged in positions becoming symmetric by sandwiching the crankshaft 21, and restrain the vibration caused by the movement of the yoke 2 together with the counterweight 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a scotch yoke engine, and more particularly, to a scotch yoke engine that can suitably suppress vibration generated during driving.

  As an engine used for automobiles and the like, there is a scotch yoke type engine using a scotch yoke mechanism, in addition to a general piston and a piston connected by a connecting rod. This Scotch yoke engine has a pair of connecting rods (hereinafter referred to as “yoke elements”), and has a yoke in which a long hole perpendicular to the extending direction of the yoke element is formed. An eccentric crankshaft is inserted into the long hole, and a mechanism for reciprocating the crankpin while rolling in the long hole is provided. In this Scotch yoke type engine, since the yoke connected to the crankshaft only reciprocates, there is no interference between the yoke and the cylinder bore wall skirt, so that the distance between the crankshaft and the piston can be shortened. Among such Scotch-yoke engines, there are those provided with four yokes, for example, those disclosed in German Patent Application Publication No. 10107921 (Patent Document 1).

  This Scotch-yoke engine has two cylinders that are adjacent to each other and provided in parallel, and two cylinders that are provided adjacent to each other and parallel to each other at a position facing the two cylinders. Further, the Scotch yoke engine has a yoke having four yoke elements to which four pistons, which are provided so as to be reciprocally movable, are respectively attached to these four cylinders. In addition, a long hole is formed in the yoke, and a crankshaft serving as an output shaft is inserted into the long hole in an eccentric state. Then, each cylinder sequentially goes through a normal engine cycle to reciprocate the yoke and rotate the crankshaft.

  Some types of Scotch-yoke engines have a balancer provided with a balance weight in order to suppress vibration associated with movement of a piston provided on the yoke. The balancer has a balancer shaft that is arranged in parallel to the crankshaft and rotates in a direction opposite to the rotation direction of the crankshaft, and a balance weight is provided at a position corresponding to a yoke attached to the crankshaft. Is. In this Scotch Yoke type engine, the balancer shaft rotates as the crankshaft rotates, and the force due to the balance weight works in the direction opposite to the inertial force accompanying the piston movement, canceling the inertial force accompanying the piston movement. To do.

However, even if such a balancer is provided, the balancer shaft and the crankshaft cannot be matched, so that an unbalanced moment due to the balance weight occurs. In order to cancel such an unbalanced moment, a two-throw crankshaft provided with two crankpins is used, a yoke is attached to each crankpin, and a balancer provided with a balance weight for each is used. The yoke is reciprocated by setting the phase difference of the yoke in each of the two throws to 180 degrees. In this way, the unbalanced moment generated by each of the two balance weights is cancelled.
German Patent Application Publication No. 10107921

  However, in the Scotch yoke engine disclosed in Patent Document 1, the point of canceling the inertial force due to the movement of the piston is not particularly considered.

  In addition, since the Scotch Yoke type engine with a balancer on the crankshaft uses a two-throw crank, the crankshaft requires a length corresponding to two throws. was there.

  Furthermore, since the balance weight corresponding to each movement of the two yokes reciprocating with a phase difference of 180 degrees is provided, a torsional moment is given to the cylinder block that supports the crank and the balancer shaft. End up. Therefore, there has been a problem that the crankshaft and the cylinder block are required to have sufficient rigidity to withstand the twisting moment.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a scotch yoke engine that can contribute to downsizing of an engine and that does not require excessive rigidity of a crankshaft or a cylinder block.

  A scotch yoke engine according to the present invention that has solved the above-described problems is provided in a first cylinder and a second cylinder that are provided in parallel to each other at opposing positions, and to each of the first cylinder and the second cylinder so as to be able to reciprocate. A scotch yoke comprising a first piston and a second piston, and a yoke for providing two yoke elements each provided with the first piston and the second piston, and transmitting a reciprocating motion of each piston to a crankpin of a crankshaft. In this type of engine, balancers that rotate in opposite directions with respect to the rotation direction of the crankshaft and are symmetric with respect to the crankshaft are provided to suppress vibration caused by reciprocating motion of each piston. .

  Further, the Scotch yoke engine according to the present invention that has solved the above problems is provided at a position facing the first cylinder and the second cylinder, and a first cylinder and a second cylinder that are adjacent to and parallel to each other, A third cylinder and a fourth cylinder that are provided adjacent to each other in parallel, and a first piston, a second piston, a third piston, and a fourth piston that are reciprocally movable from the first cylinder to the fourth cylinder. And a yoke for transmitting the reciprocating motion of each piston to the crankpin of the crankshaft, and a scotch yoke engine, Rotate in the opposite direction with respect to the rotation direction of the crankshaft to positions that are symmetrical to each other. Suppressing vibration caused by backward movement balancer in which are respectively provided.

  In these Scotch yoke type engines according to the present invention, a balancer for suppressing vibration due to reciprocating motion of the piston is provided. The balancer is arranged at a position symmetrical with respect to the crankshaft, and rotates in the opposite direction to the rotation direction of the crankshaft. For this reason, it is possible to prevent an unbalanced moment from being generated by the balancer without providing a two-throw crankshaft. Therefore, the crankshaft can be reduced in size, which can contribute to downsizing of the engine.

  Moreover, it can be set as the aspect which consists of a 4-cylinder engine which has 4 sets of cylinders and pistons.

  In such a four-cylinder engine having four cylinders and pistons, the vibration of the pistons can be suppressed and the engine can be downsized.

  Further, the balancer may be arranged so as to be separated from each other in a direction orthogonal to the cylinder shaft and the crankshaft of the cylinders facing each other.

  By arranging the balancer at such a position, the force by the balancer can be applied to the yoke in a stable state. Therefore, engine vibration can be suppressed in a more stable state.

  The balancer includes a balancer shaft disposed along the axial direction of the crankshaft and a balance weight attached to the balancer shaft, and the balance weight is disposed at a position sandwiching the crankpin. You can also.

  As described above, the balance weight having the balancer is disposed at the position where the crank pin is sandwiched, so that the torsional moment generated in the balancer can be suppressed. Therefore, excessive rigidity is not required for the cylinder block that supports the balancer.

  A crank gear that rotates together with the crank shaft is attached to the crank shaft, and a balancer gear that transmits the rotation of the crank gear to the balancer shaft is attached to the balancer shaft, and the crank shaft and the balancer shaft are relatively It can also be set as the aspect rotated in the reverse direction.

  In this way, by applying rotation of the crankshaft to the balancer shaft via the gear, it is not necessary to separately provide power for rotating the balancer shaft. Further, the rotation of the crankshaft and the rotation of the balancer shaft can be reliably synchronized.

  The scotch yoke engine according to the present invention can contribute to the downsizing of the engine. Further, it is possible to prevent excessive rigidity from being required for the crankshaft and the cylinder block.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted. FIG. 1 is a perspective view of a main part of a Scotch yoke type engine according to a first embodiment of the present invention.

  As shown in FIG. 1, a Scotch yoke engine (hereinafter referred to as “engine”) 1 according to this embodiment is a so-called four-cylinder engine, and the engine 1 includes a yoke 2. The yoke 2 is provided with four yoke elements 11, 12, 13, and 14. Of these, the first yoke element 11 and the second yoke element 12 are adjacent to each other and provided in parallel. . The third yoke element 13 and the fourth yoke element 14 are provided adjacent to each other and in parallel. Further, the third yoke element 13 and the fourth yoke element 14 are provided at positions facing the first yoke element 11 and the second yoke element 12.

  Pistons 15 to 18 are provided at the tip portions of the yoke elements 11 to 14, respectively. Among these, the 1st piston 15 and the 2nd piston 16 are each provided in the 1st cylinder and the 2nd cylinder which are provided in parallel with the mutually opposing position so that reciprocation is possible, respectively. Furthermore, the third piston 17 and the fourth piston 18 are respectively provided in a third cylinder and a fourth cylinder (not shown) provided in parallel to each other at opposite positions so as to be able to reciprocate. Thus, the engine 1 has four sets of cylinders and pistons.

  A rail 19 is formed between the first yoke element 11 and the second yoke element 12 and the third yoke element 13 and the fourth yoke element. The rail 19 is formed along a direction orthogonal to the reciprocating direction of the yoke 2, and a slider 20 is inserted into the rail 19.

  The slider 20 is rotatably attached to a crank pin 22 formed on the crankshaft 21. The crankshaft 21 is rotatably attached to a cylinder block (not shown). The crankpin 22 is formed at a position eccentric from the axis of the crankshaft 21, and the slider 20 moves along the rail 19 as the yoke 2 reciprocates. As the crank pin 22 moves up and down, the crank shaft 21 rotates.

  The crankshaft 21 is provided with a counterweight 23 at a position facing the crankpin 22 via the crankshaft 21. The counterweight 23 is in a position symmetrical to the crankpin 22 with respect to the crankshaft 21 and is an inertial force generated by the movement of the yoke 2 and the pistons 15 to 18 (hereinafter referred to as “inertial force generated by the movement of the yoke 2”). ) Centrifugal force is applied in the direction to cancel. Here, the weight of the counterweight 23 is adjusted so that the centrifugal force due to the counterweight is half (1/2) of the maximum value of the inertial force due to the movement of the yoke 2.

  Auxiliary drive pulleys (crank pulleys) and valve drive chain sprockets (not shown) are attached to the front side of the crankshaft 21, and a flywheel 25 is attached to the rear side. Further, the crankshaft 21 rotates to the position on the front side of the position where the yoke 2 is provided as the crankshaft 21 rotates. A crank gear 24 that is coaxially arranged with the crankshaft 21 and rotates with the rotation of the crankshaft 21 is attached to the crankshaft 21 at a position behind the auxiliary drive pulley.

  A first balancer 30 is provided at an upper position spaced in a direction orthogonal to the surface formed by the cylinder shafts of the first and second cylinders facing each other and the crankshaft 21. . Further, a second balancer 40 is provided at a lower position separated in a direction orthogonal to the surface formed by the cylinder shaft and the crankshaft 21. The first balancer 30 and the second balancer 40 are disposed at positions that are symmetrical about the crankshaft 21.

  The first balancer 30 has a first balancer shaft 31 disposed along the axial direction of the crankshaft 21. The first balancer shaft 31 is rotatably attached to a cylinder block (not shown), and a first balancer gear 32 is attached to a front end portion thereof. The first balancer gear 32 meshes with a crank gear 24 provided on the crankshaft 21, and the rotation of the crankshaft 21 is transmitted to the first balancer shaft 31 via the crank gear 24 and the first balancer gear 32. . The gear ratio (rotational speed ratio) between the crank gear 24 and the first balancer gear 32 is set to 1: 1, and the first balancer shaft 31 rotates in synchronization with the rotation of the crankshaft 21. Thus, the first balancer shaft 31 rotates in synchronization with the crankshaft 21 in the opposite direction.

  Further, a first front balance weight 33 is provided at the front side end of the first balancer shaft 31, and a first rear balance weight 34 is provided at the rear side end. The first front balance weight 33 and the first rear balance weight 34 have the same weight. The first front balance weight 33 and the first rear balance weight 34 are arranged in phase with each other with respect to the first balancer shaft 31.

  On the other hand, the second balancer 40 has a second balancer shaft 41 arranged along the axial direction of the crankshaft 21 as with the first balancer 30. The second balancer shaft 41 is rotatably attached to a cylinder block (not shown), and a second balancer gear 42 is attached to the front end portion thereof. The second balancer gear 42 meshes with a crank gear 24 provided on the crankshaft 21, and the rotation of the crankshaft 21 is transmitted to the second balancer shaft 41 via the crank gear 24 and the second balancer gear 42. Is done. The gear ratio between the crank gear 24 and the second balancer gear 42 is set to 1: 1, and the second balancer shaft 41 rotates in synchronization with the rotation of the crankshaft 21. Thus, the second balancer shaft 41 rotates in synchronization with the crankshaft 21 in the opposite direction.

  Further, a second front balance weight 43 is provided on the front side surface of the second balancer gear 42, and a second rear balance weight 44 is provided at the rear side end of the second balancer 40. The second front balance weight 43 and the second rear balance weight 44 have the same weight.

  The second front balance weight 43 and the second rear balance weight 44 have the same weight as the first balance weight 33 and the second balance weight 34. The second front balance weight 43 and the second rear balance weight 44 are arranged in phase with respect to the second balancer shaft 41.

  When these balancers 30 and 40 rotate on the crankshaft 21, the inertial force due to the movement of the yoke 2 causes the centrifugal force generated by the rotation of the balance weights 33, 34, 43 and 44, and the counterweight 23. It is canceled as appropriate due to the rotation. These balance weights 33, 34, 43, and 44 have the same weight. Further, the centrifugal force generated by the rotation of the balance weights 33, 34 of the first balancer 30 is adjusted to be a quarter (1/4) of the maximum value of the inertial force due to the movement of the yoke 2. Similarly, the centrifugal force generated by the rotation of the balance weights 43 and 44 of the second balancer 40 is adjusted to be a quarter (1/4) of the maximum value of the inertial force due to the movement of the yoke 2.

  The operation and action of the engine 1 according to this embodiment having the above configuration will be described.

  In the engine 1 according to the present embodiment, the pistons 15 to 18 attached to the yoke 2 enter and exit each cylinder by circulation through the engine processes of the suction process, the compression process, the combustion process, and the exhaust process in the four cylinders. As a result, the yoke 2 reciprocates. When the yoke 2 reciprocates, the slider 20 and the crankpin 22 attached to the yoke 2 move up and down relatively with respect to the crankshaft 21, and the crankshaft 21 rotates as the crankpin 22 moves up and down. .

  The rotation of the crankshaft 21 is supplied as power through a crank pulley. The rotation of the crankshaft 21 is transmitted to the first balancer shaft 31 via the crank gear 24 and the first balancer gear 32. The rotation of the crankshaft 21 is transmitted to the second balancer shaft 41 via the crank gear 24 and the second balancer gear 42. Thus, both the first balancer shaft 31 and the second balancer shaft 41 rotate in the opposite direction to the rotation direction of the crankshaft 21.

  The balance weights 33, 34, 43, and 44 are also rotated by the rotation of the balancer shafts 31 and 41. The balance weights 33, 34, 43, and 44 are attached to the yoke 2 by the centrifugal force generated by the rotational movement of the balance weights 33 and the counterweight 23 disposed at a symmetrical position with respect to the crankpin 22 via the crankshaft 21. The inertial force due to the movement of the pistons 15 to 18 is cancelled. This point will be described with reference to FIG.

  FIG. 2A is a schematic diagram of the engine viewed from the axial direction of the crankshaft, and FIG. 2B is a schematic diagram of the engine viewed from the direction orthogonal to the crankshaft. In FIG. 2A, the crankshaft 21 rotates counterclockwise, and the balancer shafts 31 and 41 both rotate clockwise. In the following description, the state where the crank pin 22 is at the uppermost end is referred to as a state where the crank angle is 0 °. FIG. 2 shows a state where the crank angle is 90 °. In FIG. 2B, the position of the cylinder S is indicated by a virtual line.

  As shown in FIG. 2A, when the crank angle is 90 °, the pistons 15 to 18 attached to the yoke 2 are moved to the leftmost side, and the crank pin 22 is in relation to the crankshaft 21. Located on the left side. At this time, the inertial force FY accompanying the movement of the yoke 2 acts on the left side of FIG. The inertia force FY accompanying the movement of the yoke 2 always acts only in the reciprocating direction (horizontal direction) of the yoke 2 and does not act in the vertical direction (vertical direction).

  On the other hand, the centrifugal force FC by the counter weight 23, the centrifugal force FB1 by the balance weights 33 and 34 provided on the first balancer 30, and the centrifugal force FB2 by the balance weights 43 and 44 provided on the second balancer 40 are all shown in the figure. 2 (a) acts on the right side in the horizontal direction. Further, since the balance weights 33, 34, 43, and 44 have the same weight, the centrifugal forces FB1 and FB2 have the same magnitude. Here, the centrifugal force FC due to the counterweight 23 is half of the inertial force FY accompanying the movement of the yoke 2, and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43 and 44 are all the movement of the yoke 2. Is one quarter of the inertial force FY. Therefore, the centrifugal force FC, FB1, FB2 due to the counterweight 23 and the balance weights 33, 34, 43, 44 cancels out the inertial force FY accompanying the movement of the yoke 2, and suppresses vibration due to the reciprocating motion of the pistons 15-18. Is done.

  Further, as shown in FIG. 2B, since the balancers 30 and 40 are provided across the crankshaft 21, the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 are as follows. Works in opposite directions. For this reason, the unbalance moment by the 1st balancer 30 and the unbalance moment by the 2nd balancer 40 can be canceled and canceled. In this way, the unbalanced moment can be canceled out with the one-throw crankshaft without using the two-throw crankshaft. Therefore, it is possible to contribute to downsizing of the engine 1 itself.

  In addition, the balance weights 33, 34, 43, and 44 are rotationally moved while maintaining the same phase. For this reason, a torsional moment is not given to the cylinder block that supports the crankshaft 21 and the balancer shafts 31 and 41. Therefore, excessive rigidity is not required for the cylinder block.

  Further, the balance of force when the crankshaft 21 is in another crank angle state will be described. FIG. 3 is a schematic view of the engine as viewed from the axial direction of the crankshaft. (A) is a crank angle of 0 °, (b) is a crank angle of 90 ° (c) is a crank angle of 180 °, (d ) Shows a state where the crank angle is 270 °. Further, FIG. 4 is a schematic view of the engine as viewed from a direction orthogonal to the crankshaft. (A) is a crank angle of 0 °, (b) is a crank angle of 90 ° (c), and a crank angle is 180 °. , (D) shows a state where the crank angle is 270 °.

  As shown in FIG. 3A, when the crank angle is 0 °, the crank pin 22 is moved to the uppermost part, and the counterweight 23 is moved to the lowermost part. In addition, the balance weights 33, 34, 43, and 44 are all moved to the top. Further, the crank pin 22, the counter weight 23, and the balance weights 33, 34, 43, and 44 are aligned on a substantially vertical line.

  In a state where the crank angle is 0 °, none of the inertial force FY due to the movement of the yoke 2, the centrifugal force FC due to the counterweight 23, and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43, and 44 do not act. However, in the vertical direction, if the balance between the centrifugal force FC by the counterweight 23 and the centrifugal forces FB1 and FB2 by the balance weights 33, 34, 43, and 44 is lost, it causes vibration.

  However, the centrifugal force FC caused by the counterweight 23 acts vertically downward, and the centrifugal forces FB1 and FB2 caused by the balance weights 33, 34, 43, and 44 all act vertically upward. Here, the centrifugal force FC by the counterweight 23 is set to be twice the centrifugal forces FB1 and FB2 by the balance weights 33, 34, 43, and 44. For this reason, the centrifugal force FC by the counterweight 23 and the centrifugal forces FB1 and FB2 by the balance weights 33, 34, 43, and 44 are offset, and vibrations by the counterweight 23 and the balance weights 33, 34, 43, and 44 do not occur. Can be.

  Further, as shown in FIG. 4A, when the crank angle is 0 °, the balance weights 33, 34, 43, and 44 are all positioned upward. For this reason, the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 work in opposite directions, so that the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 are offset. Can be countered.

  Next, as shown in FIG. 3B, in the state where the crank angle is 90 °, the inertial force accompanying the movement of the yoke 2 in the horizontal direction is centrifuged by the counterweight 23 as shown in the explanation of FIG. It can be canceled by the centrifugal force FB1, FB2 by the force FC and the balance weights 33, 34, 43, 44. Further, as shown in FIG. 4B, the balance weights 33, 34, 43, and 44 are all located at the same height as the balancer shafts 31 and 42. For this reason, the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 work in opposite directions, so the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 are offset. Can be countered.

  Further, as shown in FIG. 3C, when the crank angle is 180 °, the crank pin 22 is moved to the lowermost portion and the counterweight 23 is moved to the uppermost portion. Moreover, all of the balance weights 33, 34, 43, and 44 have moved to the lowermost part. Further, the crank pin 22, the counter weight 23, and the balance weights 33, 34, 43, and 44 are aligned on a substantially vertical line.

  In this state, the direction of the centrifugal force FC by the counterweight 23 and the centrifugal forces FB1 and FB2 by the balance weights 33, 34, 43, and 44 are compared with the state in which the crank angle shown in FIG. Are swapped up and down. Even in this state, the centrifugal force FC due to the counterweight 23 and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43, and 44 are offset, and vibration due to the counterweight 23 and the balance weights 33, 34, 43, and 44 occurs. Can not be.

  Moreover, as shown in FIG.4 (c), when the crank angle is 180 degrees, the balance weights 33, 34, 43, and 44 are all positioned below. For this reason, the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 work in opposite directions, so the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 are offset. Can be countered.

  As shown in FIG. 3D, when the crank angle is 270 °, the inertia force FY due to the movement of the yoke 2 acts on the right side in the horizontal direction. On the other hand, the centrifugal force FC due to the counterweight 23 and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43 and 44 all act on the left side in the horizontal direction. Here, the inertial force FY due to the movement of the yoke 2 is the same as the sum of the centrifugal force FC due to the counterweight 23 and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43 and 44. Therefore, the inertial force FY due to the movement of the yoke 2 can be canceled by canceling the centrifugal force FC due to the counterweight 23 and the centrifugal forces FB1 and FB2 due to the balance weights 33, 34, 43, and 44.

  Further, as shown in FIG. 4D, the balance weights 33, 34, 43, 44 are all located at the same height as the balancer shafts 31, 42. For this reason, the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 work in opposite directions, so the unbalanced moment by the first balancer 30 and the unbalanced moment by the second balancer 40 are offset. Can be countered.

  Here, the change state of the unbalanced force accompanying the change of the crank angle will be described. The unbalanced force here is an inertial force accompanying the movement of the yoke 2, a centrifugal force by the counterweight 23, and a centrifugal force by the balance weights 33, 34, 43, and 44. FIG. 5 is a graph showing a change in the unbalance force in the x direction accompanying a change in the crank angle, and FIG. 6 is a graph showing a change in the unbalance force in the y direction accompanying a change in the crank angle.

  For the x direction, as shown in FIG. 5, the inertial force FYx accompanying the fluctuation of the yoke 2 varies with sin θ with respect to the crank angle θ. Further, the centrifugal force FCx generated by the counterweight 23 varies by −1/2 sin θ. Furthermore, the centrifugal force FBx due to the balance weights 33, 34, 43, and 44 varies by −1/4 sin θ. The total forcing FTx with respect to the movement of the yoke 2 is expressed by the following (1).

FTx = FTx + FCx + 2 × FBx (1)
When the unbalanced forces FTx, FCx, and FBx are substituted into the equation (1), the total forcing force FTx is always 0 regardless of the value of θ. Accordingly, it is possible to prevent an unbalanced force from being always generated in the x direction. In this way, the complete sine wave is due to the fact that it does not contain high-order harmonics components because it uses the Scotch yoke method, unlike the conventional general crank and piston connected by connecting rods. Is.

  In the y direction, the inertial force FYy accompanying the fluctuation of the yoke 2 is always 0 regardless of the crank angle θ. In FIG. 6, this inertial force FYy is not shown. Further, the centrifugal force FCy generated by the counterweight 23 fluctuates by 1/2 sin (θ−π / 2) as shown in FIG. Further, the centrifugal force FBy due to the balance weights 33, 34, 43, and 44 varies by −1/4 sin (θ−π / 2). The total forcing FTy for the movement of the yoke 2 is expressed by the following (2).

FTy = FTy + FCy + 2 × FBy (2)
When the unbalanced forces FTy, FCy, and FBy are substituted into the equation (2), the total forcing force FTy is always 0 regardless of the value of θ. Therefore, it is possible to prevent an unbalanced force from always occurring in the y direction.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, although two balance weights 33, 34, 43, and 44 are provided on both balancers 30 and 40 in the above embodiment, one or more balance weights may be provided on each balancer. Moreover, in the said embodiment, although the balancer axis | shaft is rotated via a gear, it can also be set as the aspect which rotates a balancer using another motive power. Furthermore, the balance weights 33, 34, 43, and 44 are set to have the same weight, and the weight of the counterweight 23 is set to twice the weight of the two balance weights, but the distance relationship with the yoke 2 is adjusted. Therefore, it is possible to adopt a mode in which balance weights and counterweights having different weights are used.

It is a principal part perspective view of the Scotch-yoke type engine which concerns on this invention. (A) is the schematic diagram of the engine seen from the axial direction of a crankshaft, (b) is the schematic diagram of the engine seen from the direction orthogonal to a crankshaft. It is a schematic diagram of the engine viewed from the axial direction of the crankshaft, where (a) is a crank angle of 0 °, (b) is a crank angle of 90 ° (c) is a crank angle of 180 °, and (d) is a crank angle. Indicates a state of 270 °. It is a schematic diagram of the engine viewed from a direction orthogonal to the crankshaft, where (a) is a crank angle of 0 °, (b) is a crank angle of 90 ° (c) is a crank angle of 180 °, and (d) is a crank angle. The angle is 270 °. It is a graph which shows the change of the unbalance force of the x direction accompanying the change of a crank angle. It is a graph which shows the change of the unbalance force of the y direction accompanying the change of a crank angle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Scotch yoke type engine, 2 ... Yoke, 11 ... 1st yoke element, 12 ... 2nd yoke element, 13 ... 3rd yoke element, 14 ... 4th yoke element, 15 ... 1st piston, 16 ... 2nd piston 17 ... 3rd piston, 18 ... 4th piston, 19 ... rail, 20 ... slider, 21 ... crankshaft, 22 ... crank pin, 23 ... counter weight, 24 ... crank gear, 25 ... flywheel, 30 ... first Balancer 31 ... first balancer shaft 32 ... first balancer gear 33 ... first (front) balance weight 34 ... first (rear) balance weight 40 ... second balancer 41 ... second balancer shaft 42 ... 2nd balancer gear, 43 ... 2nd front balance weight, 44 ... 2nd back balance weight, FB1, FB2, FC ... Centrifugal force, FY ... Conventional Force, θ ... crank angle.

Claims (6)

A first cylinder and a second cylinder provided in parallel to each other at opposite positions; a first piston and a second piston provided in each of the first cylinder and the second cylinder so as to be capable of reciprocating; the first piston and the A scotch yoke engine comprising two yoke elements each provided with a second piston, and a yoke for transmitting a reciprocating motion of each piston to a crankpin of a crankshaft;
A balancer that rotates in a direction opposite to the rotation direction of the crankshaft and that suppresses vibration due to the reciprocating motion of the pistons is provided at positions symmetrical to each other across the crankshaft. Scotch yoke engine. A first cylinder and a second cylinder provided adjacent to each other in parallel, and a third cylinder and a fourth cylinder provided at positions opposed to the first cylinder and the second cylinder, provided adjacent to each other and in parallel. A first piston, a second piston, a third piston, and a fourth piston that are reciprocally provided to each of the cylinder, the first cylinder to the fourth cylinder, and the fourth piston to the fourth piston. A scotch-yoke type engine comprising four yoke elements, and a yoke for transmitting the reciprocating motion of each piston to a crankpin of a crankshaft,
A balancer that rotates in a direction opposite to the rotation direction of the crankshaft and that suppresses vibration due to the reciprocating motion of the pistons is provided at positions symmetrical to each other across the crankshaft. Scotch yoke engine.   The scotch yoke type engine according to claim 2, comprising a four-cylinder engine having four sets of the cylinder and the piston.   The balancer according to any one of claims 1 to 3, wherein the balancer is spaced apart in a direction orthogonal to the cylinder shaft and the crankshaft of the cylinders facing each other. Scotch yoke engine. The balancer includes a balancer shaft disposed along the axial direction of the crankshaft, and a balance weight attached to the balancer shaft.
The scotch yoke engine according to any one of claims 1 to 4, wherein the balance weight is disposed at a position sandwiching the crank pin. A crank gear that rotates with the crankshaft is attached to the crankshaft,
A balancer gear that transmits rotation of the crank gear to the balancer shaft is attached to the balancer shaft,
The scotch yoke engine according to claim 5, wherein the crankshaft and the balancer shaft rotate in opposite directions.

Images