JPS60192145A - Balancer device of reciprocating internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of tooth shock in a balancer driving system by dividing an idle gear positioned at the middle portion of a balancer driving system into two gears and interposing elastic bodies different in deformation characteristic between both gears. CONSTITUTION:An idle gear 21 comprises the first idle gear 21a pivoted on a cylindrical support shaft 22 and the second idle gear 21h disposed concentrically with the first idle gear which are detachably connected to each other. Two kinds of a preceding deformable elastic body 23 and a succeeding deformable elastic body 24 different in distorsion by elasticity are interposed between both idle gears. Accordingly, torque shifting between the idle gears is gradually increased so as to prevent the occurrence of tooth shock in a balancer driving system during idling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a balancer device that is used in the technical field of reciprocating internal combustion engines and for eliminating imbalance in rotational inertia during operation of the internal combustion engine. be.

(Prior art) Conventionally, in a reciprocating internal combustion engine, a counterweight of approximately 1/2 of the total reciprocating mass of the reciprocating pistons, connecting rods, etc., is placed on the crankshaft, and the same amount of counterweight is placed on the balancer shaft. A balancer device is provided which is attached to the balancer shaft and rotates the balancer shaft in the opposite direction to the crankshaft at the same speed to reduce or eliminate imbalance in rotational inertia force during reciprocating motion of the entire mass. but,
In this case, the structure becomes complicated by attaching a balancer device to the engine body, and furthermore, this balancer device interferes with the stirring lubricating oil in the crankcase during operation and receives resistance, resulting in a decrease in engine output. There was a problem that caused this.

Therefore, there are balancer devices that are installed in the dead space of the crankcase to reduce the influence of the agitated lubricating oil (for example, Jikko Shoj♂-G/G0 Otsu Publications).
It is effective to some extent as a means of preventing a drop in engine output. However, when the balancer device is driven by a gear transmission method, tooth rattling noise is generated due to the back gap between the teeth in each meshing part, and this rattling noise becomes particularly loud when the engine is running at idle. The problem is that the noise gets louder.

As a means to prevent rattling noise in the balancer drive system, as shown in Fig. 1, the balancer shaft a and the balancer gear (
Alternatively, a spring C is interposed between the sprocket) b, and the compression action of the spring causes the balancer gear b to
from θl to θ2 shown in Figure 2 for balancer lid a.
The spring C can be relatively rotated up to 100 degrees, thereby attenuating vibrations transmitted from the crankshaft (not shown) and achieving smooth torque transmission. Since the contact points that are not directly facing each other act in an oblique direction, a guide pin d is fitted to prevent the deformation, and therefore the balancer gear b rotates until the clearance e at the end of the guide pin d is closed. After that, connect the balancer l1li1 via the guide pin d.
The torque transmitted to the balancer shaft a rotates integrally with the balancer shaft a as shown in FIG. However, there are still problems that need to be resolved.

(Object of the Invention) In view of the above-mentioned conventional problems, the present invention divides the idle gear located in the middle of the balancer drive system into two gears, and interposes an elastic body with different deformation characteristics between the two gears. A balancer device for a reciprocating internal combustion engine that prevents the occurrence of tooth striking in a balancer drive system by transmitting torque from an idle gear by following a curved line 12 as shown by the chain line in FIG. is to provide.

(Structure of the Invention) The present invention is characterized in that a balancer gear provided coaxially with a balancer is meshed with an idle gear provided on a support shaft and meshed with a driven gear for transmitting torque of a drive shaft to a clutch shaft. In the idle gear, a first idle gear pivotally supported on a support shaft and a second idle gear provided concentrically with respect to the first idle gear are detachably coupled, and both idle gears 'I between gears
It is characterized by the interposition of an IE body.

(Example) Hereinafter, one example of the present invention will be described in detail based on the drawings.

Reference numeral 1 shown in FIG. 3 is a reciprocating internal combustion engine, in which a cylinder 6 is connected to one upper end of a crankcase 2 with its longitudinal axis slightly inclined with respect to the vertical line. 4 is a piston, an upper end bearing 7 of a connecting rod 6 is pivotally connected to a piston pin 5 attached to the piston, and a lower end bearing (not shown) of the connecting rod is pivotally connected to a drive shaft 8. 9 is balancer axis 1
The balancer is fixed to the cylinder 3 and is housed in a balancer chamber 11 that is partitioned and arranged in the crankcase 2 so as to be close to the cylinder 3 side. 12 is a driven gear provided on the clutch shaft 16;
A drive gear 14 provided on the drive shaft 8 and an idle gear 21 (described later) are meshed with each other, and a balancer gear 15 meshed with the idle gear is connected to the drive gear 14 during operation of the reciprocating internal combustion engine. is rotated at the same speed in the opposite rotation direction of the clutch shaft 16 from the driven gear 12.
The input torque is transmitted through a speed change gear mechanism (
output shaft 1 via the final stage gear 16 (whole illustration omitted)
7.

Reference numeral 21 shown in FIG. 7 is an idle gear, which includes a first idle gear 21a pivotally supported on a cylindrical support shaft 22;
A second idle gear 21b provided concentrically with the first idle gear is detachably coupled to the first idle gear, and
Two kinds of leading deformable elastic members 26 and trailing deformable elastic bodies 24 having different amounts of elastic strain are interposed in both idle gears.

More specifically, the support shaft 22 has a cantilever structure in which one end 25 is press-fitted and fixed to the crankcase 2 with a fitting length that is at least the diameter thereof, and the other end 26 is fixed to the crankcase 2 with a fitting length that is at least the diameter of the crankcase 2. The cover 27 is opposed to the cover 27 with a slight gap therebetween.

The first idle gear 21a has a disc-shaped stepped portion 28 formed on one side, and has an extended boss portion 29 on the stepped portion side, and three rods shown in FIG. 5 from the outer periphery of the extended boss portion. A driven projecting piece 30.30° 30 is protruded radially so that its outer side IviR can slide against the inner periphery of a rim portion 62, which will be described later, of the second idle gear 21b. In FIG. 7, 31.31 is a rolling bearing such as a needle bearing.

The Mfl second idle gear 21b is connected to the first idle gear 21a at one end of the rim portion 62 as shown in FIG.
A retaining ring part 63 is formed which is detachable from the step part 28 of the rim part 62, and one 01 ring shown in FIG.
A projecting piece 34, 34, 34 is provided in a central shape so that its inner edge can slide into contact with the outer periphery of the extension boss portion 29 of the south/idle gear 21a, and the projecting piece 34.34. By combining the driven protrusions 30, 30, 30 and the driving protrusions 34, 34.
A plurality of damper chambers 35, 3 as shown in FIG.
5... Each of the damper chambers has two leading deformable elastic bodies 26, 26 each having a damper function and formed in a triangular cross section, and a number of trailing deformable elastic bodies 24, 24, 24 formed in a trapezoidal cross section. .24 is charged, and the leading deformable elastic body 26 is provided with a narrow clearance C1 and the trailing deformable elastic body 24 is provided with a wide clearance C2 with respect to the damper chamber 35i. Further, the leading deformable elastic body 26 is disposed adjacent to the second idle gear 21k in a manner that corresponds to both normal and reverse rotation, and increases the amount of strain when the idle gear 21 rotates. While the subsequent deformable elastic body 24 is brought into line contact with the drive protrusion 34 in order to achieve this, the subsequent deformable elastic body 24 is brought into surface contact with the drive protrusion 64 in order to suppress the amount of distortion. Note that, instead of this example in which the leading deformable elastic body 23 and the trailing deformable elastic body 24 have different strain amounts depending on different cross-sectional shapes,
Those made of materials with different hardness and the same cross-sectional shape,
It is also possible to use one that is made of the same material, has the same shape, and has a flexible reinforcing material embedded in one side. Further, at least two leading deformable elastic bodies 26 are sufficient, but if necessary, a damper chamber 35 may be added to increase the number of leading deformable elastic bodies 24 together with the trailing deformable elastic bodies 24, and the position of the leading deformable elastic bodies 26 may be changed from this example. It is also possible to provide nine symmetrical positions surrounding the extension boss portion 29.

In FIG. 7, 36 is a snap ring that can be attached and detached to the extension boss portion 29 of the first idle gear 21a. The assembly of the subsequent deformable elastic body 24 fixes the shape in the axial direction. 68 is a washer that connects the first idle gear 21a.
is provided at the outer end of the washer and the support +N of the cover 27.
+ 22 The first idle gear 21a is connected to the opposite part.
axial movement is restricted. 69 is rolling bearing 6
1 is an oil hole for supplying oil, and an inflow oil passage (not shown) is connected to the oil hole via a hollow portion 40 of the support shaft 22.

Next, the operation of the apparatus of the above embodiment will be explained.

In FIG. 3, when the reciprocating internal combustion engine 1 is started and the drive shaft 8 rotates, the torque is output from the drive gear 14 via the driven gear 12 and the final stage gear 16 of the transmission gear mechanism (not shown). The torque is transmitted to the shaft 17, and the torque is also transmitted from the driven gear 12 to the balancer 9 via the idle gear 21 and the balancer gear 15.
The rotation of the balancer causes the piston 4. Imbalance in rotational inertia due to reciprocating masses such as the connecting rod 6 is eliminated. In this case, in the idle gear 21, as shown in FIG.
First, the second idle gear 21b rotates to bring its driving protrusion 34 into contact with the seven leading deformable elastic bodies 23, and then, as the second idle gear 21b continues to rotate, the driving protrusion 64 causes the leading deformation. The elastic body 23 is pressed against the driven protrusion 30 and rotated through a large relative rotation angle with respect to the first idle gear 218, thereby gradually increasing the torque to be transmitted to the first idle gear 21a. Thereafter, when the driving protrusion 64 comes into contact with the subsequent deformable elastic body 24, the second idle gear 21b presses the subsequent deformable elastic body 24 against the other driven protrusion 30.30 with the other driving protrusion 34.34. 1st Ai Dorgi p-21
&, the torque to be transmitted to the first idle gear 21a is rapidly increased.

By the way, when we conducted an experiment on the relationship between the relative rotation angle of the idle gear and the torque due to the misfire, we obtained the results shown in FIG. 4. That is, the characteristic curves A and B in FIG. 4 are good results, and the details of the two leading deformable elastic bodies 26 made of rubber whose dimensions (mm) and hardness (rubber hardness) are shown in FIG. The detailed dimensions (m) are shown in Figure 2.
m) and subsequent deformation elastic body 24 made of the same rubber showing hardness.
In the case of characteristic curve A, the turning zone where the torque changes from an initial state where the torque gradually increases to a rapidly increasing state is around 7° of the relative rotation angle. Yes, and also 8' for characteristic curve B. Located nearby, traditionally,
The rattling sound of the balancer drive system, which used to be a rattling noise during idling, has now diminished to a weak rotational sound that is difficult to hear. Further, in the above two experimental examples, it was found that by setting the turning belt at an appropriate relative rotation angle, it was possible to prevent an increase in vibration due to a timing shift of the noise lancer.

The characteristic curve C is obtained by arranging the two elastic bodies 50a shown in FIG. 2 as shown in FIG.
Although it has good durability, it cannot be used because of the noise caused by gear backlash during idling operation. The characteristic curve is one in which two elastic bodies (not shown) with a hardness of j00 are arranged, which is effective in preventing noise, but the phase shift of the balancer is large, which not only increases vibration but also reduces durability. Therefore, it cannot be adopted. The characteristic curve E is shown in Figure 2 (
Dimensions are mm) Two elastic bodies 50a shown in No. 7.2
They are arranged as shown in the figure, and the characteristic curve F
3 of the elastic body 50b shown in Fig. 70 (dimensions are mm)
The components were arranged as shown in FIG. 73, and neither of the characteristic curves E and F yielded favorable results.

(Effects of the Invention) According to the above-described structure, the idle gear is divided into a first idle gear and a second idle gear, and an elastic body having different amounts of elastic strain is interposed between the two. Since the torque to be transferred from the second idle gear to the first idle gear is transmitted with a characteristic that increases gradually at the initial stage and then rapidly increases from the turning zone, the balancer during idle operation is This has excellent effects such as not only significantly damping the teeth in the drive system, but also eliminating imbalances in rotational inertia in a timely manner.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention, FIG. 7 is a longitudinal cross-sectional view of the lance gear mounting portion, explaining a conventional example of tooth rattle prevention means for a balancer drive system, FIG. 2 is a characteristic line diagram, and FIG. Figure 3 is a central vertical sectional view of the reciprocating internal combustion engine, and Figure 7 is the I of Figure 3.
A developed view showing a part of the crankcase in a cross section parallel to the balancer axis as seen along V-IV.
4 is a damper characteristic curve diagram of the idle gear, FIGS. 7 (a) and (b) are front and side views of the leading deformable elastic body during the experiment, Figures 2 (a) and (b) are the front and side views of the subsequent deformed elastic body during the experiment, and each (a) of Figure 2 and @70.
) and (b) are front and side views of the elastic body during the experiment, Figure 1/Figure 1. ! This figure and FIG. 13 are cross-sectional views of the idle gear showing the arrangement of each elastic body in the experiment. DESCRIPTION OF SYMBOLS 1... Reciprocating internal combustion engine, 8... Drive shaft, 12... Driven gear, 13... Kura-Sochi shaft, 21... - Idle Gear, 21a...
...First idle gear, 21b...Second idle gear, 22...XIM, 26...
...Leading deformable elastic body, 24...Following deformable elastic body

Claims (2)

[Claims] (1) A balancer gear provided coaxially with a balancer is meshed with an idle gear provided on the support shaft and meshed with a driven gear for transmitting the torque of the drive shaft to the clutch shaft, and the idle gear A first idle gear pivotally supported on a support shaft and a second idle gear provided concentrically with respect to the first idle gear are removably coupled, and an elastic body is provided between the two idle gears. A balancer device for a reciprocating internal combustion engine, characterized in that a balancer device is provided for a reciprocating internal combustion engine. (2) The elastic bodies have different amounts of strain due to their elasticity, and the torque transmitted between the two idle gears increases gradually at the initial stage until the relative rotation angle of the two idle gears reaches approximately ~(l>0). 2. A balancer device for a reciprocating internal combustion engine according to claim 1, characterized in that the balancer device has a characteristic that increases rapidly if the increase occurs.