JPS63101538A - Balance shaft driving device for engine - Google Patents

Abstract

PURPOSE:To cancell rolling moment by disposing a pair of balance shafts outside an engine body, and controlling the balance shafts through a rotary driving device according to a crank angular velocity and a crank angle. CONSTITUTION:A pair of balance shafts 13, 14 on both right and left sides outside an engine body 11. A control device 21 is adapted to control the rotating speed of motors 17, 18 according to electric signals input from detecting portions 22, 23 for detecting an angular velocity and a crank angle of a crank shaft 12. Accordingly, rolling moment of an engine can be cancelled effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a balance shaft drive device for an engine, and more particularly to a balance shaft drive device that cancels the excitation force caused by an explosion occurring in the engine.

[Conventional technology]

In the case of an engine, for example a 4-cycle in-line 3-cylinder engine, as shown in FIG.
is connected to the crank arm 2 via a connecting rod 3.

During operation of the engine, an unbalanced pitching moment (negative inertia couple) is generated around the second cylinder due to inertial forces acting on reciprocating members such as the piston, piston pin, and small end of the connecting rod.

To deal with this pitching moment P, for example, as disclosed in Japanese Patent Publication No. 56-38814, by half-balancing each cylinder, the smooth inertia couple generated in the crankshaft system can be reduced to a single balance. An inertia couple removal device for a three-cylinder engine is known in which the inertia couple is removed by a shaft.

Even if the pitching moment P is removed or reduced in this way, the excitation moment (rolling moment) M caused by the explosion poses a problem in terms of vibration countermeasures.

In order to remove the excitation moment caused by this explosion,
For example, a balancer device for a three-cylinder engine is known as disclosed in Japanese Unexamined Patent Publication No. 59-187133. In this balancer device, as shown in FIG. , the balance weights 8 and 9 are respectively disposed so that the moment M' generated by the rotation thereof is in a direction that cancels the oscillation moment M of the engine due to the explosion. And balance shafts 6 and 7 are crankshaft 5 and chain 1
They are driven in conjunction with 0 etc.

(Problems to be Solved by the Invention) As described above, the balancer device of the conventional engine is installed inside the engine body, so there are difficulties in designing the engine.
Since the driving force of the crankshaft was transmitted to the balance shaft via a chain etc., there was also the problem of noise.

Furthermore, in the case of a 4-stroke 3-cylinder engine, during its operation,
As described above, a pitching moment P caused by the reciprocating member and a rolling moment M caused by the explosion occur, but the pitching moment P can be removed by using a half-balanced balance shaft.

However, regarding the rolling moment M, torque harmonics generate moments that are multiples of 1.5, and in the low and medium speed range of the engine, the 1° 5th order component is the largest, and in the high speed range, the 3rd order component becomes large. It has been known. Then, this third-order component resonates with the natural vibration of the support system of support parts such as the injection pump and alternator, which are engine auxiliary equipment, causing damage to the bracket and an increase in indoor noise.

In the low and medium speed range, the aforementioned balancer device (Japanese Patent Laid-Open No. 59-18
However, during high-speed operation, the third-order component moment cannot be removed by a balance shaft that rotates at 1.5 times the speed of the crankshaft.

Therefore, in order to remove the third-order component moment, it can be removed by rotating the balance shaft at three times the speed of the crankshaft, but if it is driven by a chain etc. Switching requires a complicated structure, and providing a balance shaft that rotates at 3 times the speed in addition to the balance shaft that rotates at 1.5 times the speed increases the number of parts and costs, as well as space and weight. This is difficult because it leads to an increase in the number of cases.

Further, when the balance shaft is driven by a chain or the like, the meshing noise between the balancer sprocket and the chain becomes a further noise source, which is a problem in addition to the noise inside the vehicle caused by the vibration of the engine body.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an engine balancer shaft drive device that is capable of providing a balance shaft outside the engine for canceling the rolling moment of the engine and controlling the balance shaft.

Another object of the present invention is to provide a balance shaft drive device for an engine in which the rotational speed of the balance shaft is variable in a low-medium speed range and a high-speed range, and the rotational drive of the balance shaft is not dependent on a crankshaft. There is a particular thing.

[Means for solving problems]

As a means for achieving the above object, a balance shaft drive device for an engine according to the present invention includes a pair of balance shafts arranged outside an engine main body, parallel to the crankshaft, and having an eccentric mass; , a detection means for detecting the angular velocity and crank angle of the crankshaft, and a control means for controlling the rotation drive means based on the output of the detection means.

In this case, the control means sets the angular velocity of the balance shaft to 1.5 of the crankshaft, corresponding to the low-medium speed range and the high-speed range.
It is preferable to control the rotational drive means so that the rotation can be changed to double or triple.

[For production]

In the present invention, the control means inputs the angular velocity and crank angle of the crankshaft as signals from the detection means, controls the rotation drive means of a pair of balance shafts arranged parallel to the crankshaft and having eccentric masses, and controls the rotation of the pair of balance shafts having eccentric masses. To establish a predetermined relationship between a shaft and a balance shaft so as to cancel rolling moment.

In addition, when it is detected that the rotation speed of the crankshaft has exceeded the set value, the rotation speed of the balance shaft is controlled to 1.5 to 3 times the rotation speed of the crankshaft, thereby reducing the rolling moment in the low and medium speed range. 1.
5th component and rolling moment in high speed range
The following components can be removed.

〔Example〕

An embodiment of the balance shaft drive device for an engine according to the present invention will be described below.

1(a) and (b) show an embodiment of the present invention, in which 11 is one cylinder part of an in-line three-cylinder engine body, 12 is a crankshaft, and 13 and 14 are both left and right sides outside of the engine body 11. A pair of balance shafts 15 and 16 are provided on the pair of balance shafts 13 and 14, respectively, and 17 and 18 are bearings 19.
and a balance shaft 13 rotatably supported by 20.
and 14, the motor 21 includes an input interface 25, a CPU 26, a memory 27, and an output interface 28, and receives electrical signals from detection units 22 and 23 that detect the angular velocity and crank angle of the crankshaft 12, respectively. This is a control device that controls the rotational speed of motors 17 and 18. Note that the output interface 28 includes a drive device (not shown) for driving the motors 17 and 18.

In the conventional balancer device shown in FIG. 4, the balance shafts 6 and 7 are connected to and driven by the crankshaft 5 through a chain 10, and therefore are placed inside the engine body 11, but in the present invention Since the balance shafts 13 and 14 are driven by the motors 17 and 1B, the balance shafts 13 and 14 are connected to the engine body 11.
It is not necessary to place it inside the engine body 11, but it can be attached to the outside side wall of the engine body 11 symmetrically to the crankshaft 12.

The balance weights 14 and 15 provided on the balance shafts 13 and 14 are arranged so that the moment generated by their rotation cancels out the oscillation moment caused by the explosion, and the balance weights 14 and 15 are attached to the axis of each balance shaft, similar to a conventional balancer device. The centers of gravity are shifted relative to each other, and a mutual phase difference of 180° is provided so that the centers of gravity are always upward and downward, respectively. And the direction of rotation is balance shaft 1
3 and 14 and the crankshaft 12 are the same.

As shown in the figure, the crankshaft 12 is located at a position where the piston in one cylinder has passed the explosion top dead center, that is, when a large explosion pressure acts on the piston, an excitation moment M is generated.
is at the maximum position (crank angle θ0), the balance weight 15 on one balance shaft (if the excitation moment M is in the counterclockwise direction as shown in the figure, the left balance shaft) 13 is located above the axis, and the balance weight 16 of the other balance shaft (also the right balance shaft) 14 is located below.

The control operation of the balance shaft drive device for the in-line three-cylinder engine configured as described above will be explained.

The piston of the first cylinder in an in-line three-cylinder engine is shown in Figure 1 (
It is assumed that the engine is in the position shown in a), and an excitation moment M is generated due to the explosion of the first cylinder. At this time, since the pair of balance weights 15 and 16 are deviated upward and downward, respectively, centrifugal force F is applied to the balance weight 15.
1, and a centrifugal force F2 is generated on the balance weight 16, and these centrifugal forces F and F2 cause a moment M'
(-Fl ・J-F ・1: where 1 is the distance between the crankshaft and the balance shaft) occurs.

Since the direction in which this moment M° acts is the opposite direction (clockwise) to the excitation moment M, the moment M can be canceled by the moment M° by adjusting the magnitude of the moment M''. .

As shown in FIG. 1(a), m<crank angle θ. ) as a reference state, the crankshaft 12 is moved 24 times from the reference state.
0" rotation, that is, when the first cylinder is in the middle of the exhaust stroke, the piston of the second cylinder comes to a position of crank angle θ from the explosion top dead center, and the excitation moment l due to the explosion of the second cylinder
-M occurs again.

In a four-stroke in-line three-cylinder engine, each cylinder explodes once every two revolutions (720') of the crankshaft, so each cylinder explodes sequentially every 240@ of the crankshaft.

On the other hand, if the balance shafts 13 and 14 are rotated at 1.5 times the speed of the crankshaft 12, while the crankshaft 12 rotates 240', the balance shaft 1
3 and 14 will rotate 360 degrees, and when the crankshaft 12 rotates 240' from the standard state and an excitation moment M is generated in the engine body 11 due to the explosion of the second cylinder, the balance in the balance shafts 13 and 14 will change. The centrifugal forces F and F2 acting on the weights 15 and 16 generate a moment M°, which can cancel out the excitation moment l-M caused by the explosion of the second cylinder.

Therefore, as shown in the flowchart of FIG. 2 (stored in the memory 27), the detection units 22 and 23 detect the angular velocity and crank angle of the crankshaft 12 (step Sl), and in step S2 it is determined that the speed is in the low speed range. When the angular velocity of the motors 17 and 18 is controlled to be 1.5 times that of the crankshaft 12,
The phases of the motors 17 and 18 may be controlled so that the phase of the balance shafts 13 and 14 becomes 1.50 with respect to the phase θ of (step S3).

By the way, while the rotation of the crankshaft 12 is in the low-medium speed range, the 1.5-order component of the excitation moment M shows the maximum value, but when it enters the high-speed range, the 3rd-order component becomes the maximum. balance shafts 13 and 14 to crankshaft 1
Even if it rotates at a speed 1.5 times faster than 2, the excitation moment M cannot be canceled out.

Therefore, in order to cancel the third-order component of the excitation moment M in the high-speed range, the balance shafts 13 and 14 are operated at an angular velocity three times that of the crankshaft 12, and with respect to the phase θ of the crankshaft 12. 14
The motors 17 and 18 may be controlled so that the phase of the phase becomes 30 (step S4 in FIG. 2).

The low-medium speed range and the high-speed range are determined based on whether the angular velocity of the crankshaft is below or above a predetermined value (step S2). That is, it is determined whether the detection signal of the detection unit 22 is larger than the set value Ω stored in the memory 27, and the motors 17 and 18 are driven by the control device 21 according to the procedure according to the flowchart shown in FIG. Just do it.

In the embodiment shown in FIGS. 1(a) and 1(b), the pair of balance shafts 13 and 14 are arranged symmetrically on both the left and right sides of the crankshaft 12.
2 or the center of gravity of the engine body 11 may be placed above on one side and below on the other side, similar effects can be obtained.

Furthermore, although the angular velocity of the crankshaft was detected and used for control, by calculating the average value of the angular velocity using the CPLI 26, it is possible to perform control that is completely equivalent to the case where the engine rotation speed is detected.

〔Effect of the invention〕

As described above, according to the present invention, a pair of balance shafts are provided on the outside of the engine body, and these are controlled via a rotational drive device according to the crank angular velocity and crank angle.
Since it can be installed in existing engines without requiring major design changes to the engine, it has the effect of improving the performance of existing engines.

In addition, by driving a pair of balance shafts at variable speeds, for example, 1.5 times and 3 times the crankshaft, depending on the crank angular speed, the oscillation moment of 1.5 times the excitation moment due to the explosion of each cylinder, especially 1. The 5th and 3rd order components can be canceled out.

For this reason, it is possible to significantly reduce the vibration caused by the engine not only in the low and medium speed range but also in the high speed range, which not only provides comfortable continuous high speed driving, but also reduces noise during high speed rotation, so it is virtually noiseless. This has the effect of widening the previously restricted rotational range of the engine, allowing the engine to fully demonstrate its performance.

Furthermore, since the vibration of the auxiliary equipment bracket is reduced, it is not only effective in terms of durability but also allows weight reduction.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) show an embodiment of the balance shaft drive device for an engine according to the present invention; FIG. 1(a) is a front view of the balance shaft drive device, and FIG. 1(b) is a front view of the balance shaft drive device. FIG. 2 is a flowchart of a program stored in the memory of the control device of the present invention and executed, and FIG. 3 is a diagram illustrating the moment generated in the in-line three-cylinder engine. , FIG. 4 is a diagram illustrating a conventional balance shaft drive device. In the figure, 11 is the engine body, 12 is the crankshaft,
13 and 14 are balance shafts, 15 and 16 are balance weights, 17 and 18 are motors that drive the balance shafts, 21 is a control device, and 22 and 23 are detection units. In the drawings, the same reference numerals indicate the same or corresponding parts. Patent Applicant: Isu-'Jidosha Co., Ltd. Representative Patent Attorney Shuuji Shige Izumi (Figure 1 Figure 4 Procedures by Sei Fu) December 1985 10EI 1. Indication of the case 1988 Patent Application No. 246408 No. 2, Name of the invention Organization's balance shaft drive device 3, Relationship with the case of the person making the amendment Patent applicant address 6-22-10 Minami-Oi, Parts Ward, Tokyo Name (017) Isuri Motor Co., Ltd. representative
Tobiyama - Male 4, Agent Postal code 103 Address
2-1-3-6, Horidome-cho, Nihonbashi, Chuo-ku, Tokyo Contents of amendment (1) The scope of the claims will be amended as shown in the attached sheet. (2) "Engine" on page 6, line 9 of the specification, page 7, line 1, and page 14, line 18 of the specification are respectively corrected to "in-line three-cylinder engine." (3) Figure 1 of the drawings attached to this application is amended as shown in the attached sheet. (Attachment) 2. Claims (1) A pair of balance shafts arranged outside the main body of the engine, parallel to the crankshaft, and having an eccentric mass; A balance shaft drive device for an engine that variably drives the engine, comprising: means for detecting the angular velocity and crank angle of the crankshaft; and a control means for controlling the rotational drive means based on the output of the detection means. . (2) The rotation driving means is under the control of the control means,
1 of the angular velocity depending on the angular velocity of the crankshaft.
The balance shaft drive device for an engine according to claim 1, wherein the balance shaft is variably driven in two stages: 5 times and 3 times. (3) The balance shaft drive device for an engine according to claim 1, wherein a motor is used as the rotation drive means for the balance shaft, and the rotation speed of the motor is made variable by the control means. (4) using a microcomputer as the control means;
Record the setting value for the signal obtained by the detection means.
The balance shaft drive device for an engine according to claim 1, wherein the balance shaft drive device for an engine according to claim 1 controls the rotation drive means.

Claims (5)

[Claims] (1) A pair of balance shafts arranged outside the engine body, parallel to the crankshaft, and having an eccentric mass, means for rotationally driving the balance shafts, and detection for detecting the angular velocity and crank angle of the crankshafts. 1. A balance shaft drive device for an engine, comprising: a control means for controlling the rotation drive means based on the output of the detection means. (2) The rotation driving means is under the control of the control means,
1 of the angular velocity depending on the angular velocity of the crankshaft.
The balance shaft drive device for an engine according to claim 1, wherein the balance shaft is variably driven in two stages: 5 times and 3 times. (3) The balance shaft drive device for an engine according to claim 1, wherein a motor is used as the rotation drive means for the balance shaft, and the rotation speed of the motor is made variable by the control means. (4) using a microcomputer as the control means;
2. The balance shaft drive device for an engine according to claim 1, wherein a set value for a signal obtained by said detection means is stored and held, and said rotation drive means is controlled. (5) The balance shaft drive device for an engine according to claim 1, wherein the engine is an in-line three-cylinder engine.