JPH0941983A - Gear train of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the maximum torque to be imposed on a gear train as low as possible by way of making the driving torque variation of a driving gear so as not to be transmitted to any auxiliaries, miniaturize and lighten the weight of the gear train and reduce in manufacturing cost. SOLUTION: In this gear train 11 of an internal combustion engine made up of interposing an idle gear 15 between a driving gear 14 and a driven gear 26, this idle gear 15 is constituted shiftably in the thrust direction. In addition, it is provided with an elastic body 22 which makes its elastic force act on the idle gear 15 in opposition to any thrust force to be produced by driving torque of the driving gear 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear train of an internal combustion engine including a gear provided on a drive shaft, such as a crankshaft of a reciprocating engine, whose rotational angular speed fluctuates during one rotation.

[0002]

2. Description of the Related Art An internal combustion engine is equipped with various auxiliaries such as an alternator, a compressor, a pump, a fan, and the like. To drive these, a drive shaft formed at one end of a crankshaft is mounted. With a crank gear,
The driving force is transmitted to an accessory driving gear provided on a driven shaft of the accessories.

In the case of the above-mentioned gear drive, the backlash is neglected and the connection is almost rigid. As shown in FIG. 4, the number of teeth N ₁ of the crank gear 1 is 30 and the number of teeth N _{2 of the} idle gear 2 is N _2.
= 20 and the number of teeth N _{3 of} the auxiliary drive gear 3 = 10, the rotational angular velocity fluctuation (slow in compression stroke and faster in expansion stroke) during one rotation of the crank gear 1 is tripled. Is transmitted to the accessory drive gear 3 as the rotational angular velocity fluctuation of

In recent years, for example, in order to reduce the size of an alternator and increase the amount of power generation, there is a tendency to increase the gear ratio and increase the number of revolutions. This will be explained by exemplifying the case of a single cylinder engine in FIG. 5, and the instantaneous rotation speed of the crank gear 1 is 50
When it is set to 0 rpm, it is decelerated in the compression stroke and accelerated in the expansion stroke, so that a speed fluctuation of 20 rpm (± 10 rpm) occurs, whereas the average rotation speed of the accessory drive gear 3 is increased three times. Therefore, it will be 1500 rpm, and a speed fluctuation of 60 rpm (± 30 rpm) will occur. Further, in the case of a multi-cylinder engine, the speed fluctuation of each cylinder is combined.

[0005]

As described above, if the speed is increased three times in order to reduce the size of the auxiliary machine, the speed fluctuation is also tripled.
Further, since the auxiliary machine has inertia, in the case of a single cylinder engine, the average drive torque T _{A is} applied to the gear train as shown in FIG.
It is necessary to adopt a gear train that can generate a fluctuation torque that exceeds the maximum torque T _M , and, in the case of a multi-cylinder engine, a combination of fluctuation torques for each cylinder, so a gear train that can withstand it is used. As a result, both the cost and the weight increase significantly, and in the worst case, there is a problem in that it cannot be established due to restrictions such as space and material.

In view of the above-mentioned problems, the present invention reduces the maximum torque applied to the gear train as much as possible by preventing the drive torque fluctuation of the drive gear from being transmitted to the auxiliary machine. An object of the present invention is to provide a gear train for an internal combustion engine that can reduce the size and weight of the train and reduce the manufacturing cost.

[0007]

The gear train of an internal combustion engine according to the present invention for achieving the above object is a gear train of an internal combustion engine in which an idle gear is interposed between a driving gear and a driven gear. Is configured to be movable in the thrust direction, and an elastic body that applies an elastic force to the idle gear in opposition to the thrust force generated by the drive torque of the drive gear is provided.

Each gear constituting the gear train includes
Uses a helical gear to allow the idle gear to slide in the thrust direction (axial direction). Then, by utilizing the thrust direction force generated in the idle gear, slide the idle gear to change the speed of the crank gear.
Do not transmit to the accessory drive gear. As a method of configuring the idle gear to be movable in the thrust direction,
For example, it is preferable that a metal is interposed between the idle gear and a spindle of the idle gear so that the idle gear is slidably supported on the spindle so as to be rotatable and axially slidable.

As the elastic body for exerting an elastic force on the idle gear, various springs such as coil springs and disc springs, rubber and highly elastic plastic materials, and various fluid cylinders such as air cylinders are used. However, the elastic body is not particularly limited, and the point is that the elastic body can be biased against the thrust force generated by the driving torque of the driving gear.

Further, in order to prevent the idle gear from coming off, it is preferable to provide a stopper on the spindle of the idle gear to limit the amount of movement of the idle gear, and to further support the load acting in the thrust direction, Moreover, in order to keep the idle gear rotating smoothly, it is more preferable to provide a thrust bearing on the side surface of the idle gear.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a gear train of an internal combustion engine according to the present invention will be described with reference to the drawings. As shown in FIG. 1, in the gear train 11 of this embodiment, a drive flange (not shown) is formed at one end of the crankshaft 12, and the auxiliary drive shaft 13 is formed at the other end.
Are formed. A crank gear 14, which is a drive gear, is fixed to the accessory drive shaft 13, and an idle gear 15 is meshed with the crank gear 14. The idle gear 15 is supported by an idle gear shaft 16 serving as a support shaft via a metal (not shown), and thrust bearings 17 and 18 are provided on both side surfaces of the idle gear 15, respectively. There is.

A spring seat 19 is provided so as to abut on a thrust bearing 17 on the left side in the figure, and another spring seat 21 is also provided so as to abut on a head portion 20 of the idle gear shaft 16. . A spring 22 is interposed between the spring seats 19 and 21 as an elastic body that biases the idle gear 15 to the right in the figure. Also, on the right end of this idle gear shaft 16,
The stopper 23 is fixed and limits the movement amount of the idle gear 15 to perform a retaining function.

Further, in addition to the crank gear 14, the idle gear 15 is meshed with an accessory driving gear 26 which is a driven gear fixed to a driven shaft 25 of an accessory 24 such as an alternator. . In addition, the crank gear 14, the idle gear 15,
The auxiliary machine drive gear 26 is composed of a helical gear. Next, the operation of this embodiment will be described. First, as shown in FIG. 1, when the crank gear 14 rotates in the direction of the arrow, a thrust force in the direction of the arrow A is generated in the idle gear 15 in proportion to the driving torque. The position of the idle gear 15 is balanced at the position shown in the figure by pushing the idle gear 15 in the direction of arrow B by the spring 22 having a set load that balances the generated thrust force.

Next, when the crank gear 14 is accelerated in the expansion stroke and the instantaneous value of the rotation speed of the idle gear 15 becomes larger than the average rotation speed, the driving force acting on the idle gear 15 becomes large and the arrow A Since the thrust force in the direction also increases, the idle gear 15 moves in the direction of arrow A as shown in FIG. 2, and the crank gear 14 and the accessory drive gear 26 are out of phase in the rotational direction, and the accessory drive gear. 26 is prevented from being forcibly accelerated due to fluctuations in rotation, and excessive torque is prevented from being generated.

On the contrary, when the crank gear 14 is decelerated in the compression stroke and the instantaneous value of the rotation speed of the idle gear 15 becomes smaller than the average rotation speed, the driving force acting on the idle gear 15 becomes small, and the idle gear 15 moves in the direction of arrow A. Since the thrust force is also small, as shown in FIG.
This prevents the crank force 14 from moving in the direction of the arrow B due to the elastic force of the crank gear 14 and the phase of the auxiliary drive gear 26 in the rotational direction being deviated, and the auxiliary drive gear 26 from being forcibly decelerated by rotational fluctuation Therefore, generation of excessive torque is prevented.

As described above, the idle gear 15 formed as a helical gear is slid by the action of the thrust force acting in the axial direction and the spring force of the spring 22, so that the crank gear 14 and the accessory drive gear Since the phase of the rotation direction of 26 can be shifted, and the fluctuation of the rotation speed of the crank gear 14 can be prevented from being transmitted to the accessory drive gear 26, the accessory drive gear 26 must always rotate at a constant speed. Therefore, the gear train 11 does not generate excessive fluctuating torque. In this embodiment, the coil spring is used as the spring 22, but instead of this, a disc spring, an air cylinder or the like may be used.

[0017]

The gear train of an internal combustion engine according to the present invention is a gear train of an internal combustion engine in which an idle gear is interposed between a driving gear and a driven gear, and the idle gear is movable in the thrust direction. Since an elastic body that applies an elastic force to the idle gear is provided in opposition to the thrust force generated by the drive torque of the drive gear,
The following effects can be achieved.

Since the variation in the rotational speed of the crank gear is not transmitted to the accessory drive gear, the accessory drive gear can always be rotated at a constant speed. As a result, even if the rotational speed is increased to reduce the size of the auxiliary machinery, the speed of the auxiliary drive gear does not fluctuate, and therefore it is possible to prevent the fluctuating torque from being generated in the gear train. . Further, since the variable torque is not generated in the gear train, the excessive torque that greatly exceeds the average driving torque is not generated, and it is not necessary to have the strength as in the past, so that a small, lightweight and inexpensive gear train is provided. In particular, when the speed increasing ratio is large and the inertial mass of the driven auxiliary machine is large, it is more effective.

Further, since the torque fluctuation can be suppressed, the driving state of the gear train can be stabilized, the durability of the gear train can be improved, and the gear striking sound can be reduced to lower the noise level. be able to.

[Brief description of drawings]

FIG. 1 is a side view of a gear train of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a side view of the internal combustion engine gear train shown in FIG. 1 in an expansion stroke.

3 is a side view of the compression train of the gear train of the internal combustion engine shown in FIG. 1. FIG.

FIG. 4 is a front view schematically showing a gear train of a conventional internal combustion engine.

5 is a characteristic diagram showing fluctuations in rotational speed of the gear train of the internal combustion engine shown in FIG.

6 is a characteristic diagram showing drive torque fluctuations of the gear train of the internal combustion engine shown in FIG.

[Explanation of symbols]

 11 Gear train 14 Crank gear (drive gear) 15 Idle gear 22 Spring (elastic body) 26 Auxiliary machine drive gear (driven gear)

Claims (1)

[Claims] 1. In a gear train of an internal combustion engine in which an idle gear is interposed between a driving gear and a driven gear, the idle gear is configured to be movable in a thrust direction, and
A gear train for an internal combustion engine, comprising an elastic body that applies an elastic force to the idle gear in opposition to a thrust force generated by a drive torque of a drive gear.