JPH0874976A - Gear device - Google Patents

Abstract

(57) [Summary] [Purpose] To suppress the generation of gear rattling noise due to backlash and prevent the increase of unnecessary friction. [Structure] A balancer device 8 for an internal combustion engine includes a drive gear 10 which rotates integrally with a crankshaft about an axis L of a crank journal 4 and a first gear 10 meshed with the drive gear 10.
And the driven gear 17 of. On the circle centered on the axis L on the side surface of the drive gear 10, at a position where the drive gear 10 and the driven gear 17 mesh with each other when the tendency of fluctuation of the angular acceleration in the drive gear 10 changes due to the combustion cycle of the internal combustion engine. , Attach the elastic bodies 27a, 27b, 27c, 27d. Each elastic body 27a to 27d
Applies more rotational resistance to the driven gear 17 than other timings in accordance with the change timing of the angular acceleration periodically generated in the drive gear 10. By imparting the rotation resistance, the relative rotation of both gears 10 and 17 is restricted, and the collision between the teeth 11 and 18 is mitigated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear device including an input side gear and an output side gear meshed with the gear so as to transmit power between the both gears.

[0002]

2. Description of the Related Art Generally, as a mechanism for transmitting the rotation of one shaft to the other shaft between two shafts, so-called gears in which gears are integrally rotatably mounted on the respective shafts and the gears are meshed with each other. The device is known. In this gear device, there is a problem that a rattling noise is generated due to a gap (backlash) between teeth in a meshing portion of both gears.

Therefore, a gear device that solves the above problems at low cost is disclosed, for example, in Published Technical Report No. 89-5920 (issued by the Japan Institute of Invention and Innovation). In this device, a disk-shaped elastic body is fixed to the side surface of the input-side gear, and the teeth of the output-side gear are in pressure contact with this elastic body. According to this gear device, when the input-side gear is rotated, the rotation is transmitted to the output-side gear via the elastic body. Due to the interposition of the elastic body, direct contact between the teeth of both gears is suppressed, and generation of rattling noise is prevented.

[0004]

In the conventional gear device,
As described above, the elastic body is interposed in the transmission path of the rotational force from the input-side gear to the output-side gear, and any tooth of the latter gear is always in pressure contact with this elastic body. Therefore, the gear device can suppress the contact of the teeth between both gears and prevent the generation of rattling noise, but the teeth make contact while deforming the elastic body, which increases friction and energy loss. Occurs.

This phenomenon is particularly problematic when gear rattle is generated only in a predetermined rotation phase of the gear. For example, in an internal combustion engine of a type in which reciprocating motion of a piston is converted into rotational motion of a crankshaft via a connecting rod to obtain power, rotational speed (or angular acceleration) of the crankshaft is synchronized with a combustion cycle of air-fuel mixture. Fluctuates. When the above gear device is applied to such an internal combustion engine and the rotation of the crankshaft is used to operate the gear device, when the fluctuation of the angular acceleration changes from increase to decrease, or from decrease to increase. Only when it makes a loud rattling noise. Almost no generation of rattling noise was observed at other timings. Therefore, even when such a rattling noise is small, if the teeth of the gear on the output side are brought into pressure contact with the elastic body, friction is unnecessarily increased and energy loss occurs.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a gear device capable of suppressing the generation of gear rattling noise caused by backlash and preventing an increase in unnecessary friction. It is in.

[0007]

To achieve the above object, the present invention provides an input gear, an output gear meshed with the input gear, and an input or output gear. Rotational resistance imparting means for imparting more rotational resistance to the output-side gear or the input-side gear than at other timings is provided in accordance with the cyclically-generated variation timing of the angular acceleration.

[0008]

When the gear on the input side is rotated, the rotation is transmitted to the gear on the output side meshed with the gear. This transmission causes the gear on the output side to rotate.

The angular acceleration of the gear on the input side (or the output side) fluctuates periodically. When the tendency of the angular acceleration change in one gear changes (when the change changes from increase to decrease or from decrease to increase), the other gear tries to rotate while maintaining the previous angular acceleration due to inertia. To do. Therefore, at the timing when the tendency of the fluctuation of the angular acceleration changes, both gears relatively rotate due to the backlash existing between the teeth in the meshing part of both gears, the teeth of both gears come into contact with each other, and a rattling noise is generated. It will be easier.
However, at this timing, a large amount of rotational resistance is imparted by the rotational resistance imparting means to the gear whose variation tendency has not changed. This rotation resistance suppresses the relative rotation of the gear whose tendency does not change with respect to the gear whose tendency of fluctuation changes. As a result, contact between the teeth of both gears is prevented or suppressed.

On the contrary, at the timing when the tendency of the fluctuation of the angular acceleration does not change, the rotation resistance by the rotation resistance applying means becomes smaller than at the timing when it changes. For this reason, compared to the case where the rotational resistance is always applied (conventional technology), the increase in friction due to the application is reduced.

As described above, at the timing when the tendency of the fluctuation of the angular acceleration is changed and the rattling noise is likely to be generated, the suppression of the rattling noise is prioritized over the reduction of the friction, and a large rotational resistance is given. Since it is not necessary to suppress the rattling sound at the timing when the rattling sound is hardly generated irrespective of the tendency of the fluctuation of the angular acceleration, the application of the rotational resistance is suppressed. As a result, it is possible to prevent an unnecessary increase in friction due to the application of rotational resistance.

[0012]

【Example】

(First Embodiment) Hereinafter, the gear device of the present invention is provided in an internal combustion engine, and is used as a balancer device for eliminating the inertial force and the inertia couple due to a piston, a connecting rod, etc. to damp the vibration of the internal combustion engine. FIG. 1 shows a first embodiment embodied in FIG.
9 to 9.

As shown in FIGS. 2 and 3, there are multiple cylinders (for example, 4 cylinders).
A crankshaft 3 is provided in a cylinder block 2 of an internal combustion engine 1 having a cylinder. The crankshaft 3 is for converting the reciprocating motion of the piston into a rotary motion to take out power, and is composed of a crank journal 4, a crankpin 5, a crank arm 6, a counterweight 7, and the like. The crankshaft 3 is rotatably supported by the cylinder block 2 at a crank journal 4. A piston is connected to each crank pin 5 via a connecting rod.

A balancer device 8 is provided on the crankshaft 3 and below the crankshaft 3. Explaining this device 8, each one side portion (left side portion in FIG. 3) of a predetermined crank arm 6 and counterweight 7 is constituted by a mounting portion 9 having an axis L of the crank journal 4 as its own rotation center. There is. A drive gear 10 as an input-side gear is fixed to the outer periphery of the mounting portion 9.

A pair of upper and lower housings 12, 13 are arranged immediately below the drive gear 10, and these housings 12 and 13 are composed of a plurality of bolts 1.
It is fastened and fixed to the cylinder block 2 by 4.
A first balance shaft 15 is arranged in both housings 12 and 13. As shown in FIGS. 1 to 3, the balance shaft 15 includes a shaft 16, a first driven gear 17 as a gear on the output side, and a vibration damping weight 19. The shaft 16 is arranged parallel to the axis L of the crank journal 4 and is rotatably supported between the housings 12 and 13. The driven gear 17 has half the teeth 18 of the drive gear 10 and is meshed with the teeth 11 of the drive gear 10. Both the driven gear 17 and the weight 19 are integrally rotatably mounted on the shaft 16.

A second balance shaft 20 is provided in each of the housings 12 and 13 in the vicinity of the lateral side of the balance shaft 15. Balance shaft 20 is first
Similar to the balance shaft 15 of FIG. 1, it includes a shaft 21, a second driven gear 22, and a vibration damping weight 24. Axis 21
Are arranged parallel to the axis 16 of the balance shaft 15 and are rotatably supported between the housings 12 and 13. The driven gear 22 has half the teeth 23 of the drive gear 10 and is formed thinner than the first driven gear 17. The driven gear 22 is integrally rotatably mounted on the shaft 21 at a position slightly deviated from the driving gear 10 in the direction of the axis L so as not to interfere with the driving gear 10 and meshed with the first driven gear 17. The weight 24 is also mounted on the shaft 21 so as to be integrally rotatable.

According to the balancer device 8 configured as described above, when the drive gear 10 rotates integrally with the crankshaft 3, the rotation is transmitted to the first driven gear 17, the driven gear 17, the shaft 16 and the driven gear 17. The weight 19 rotates integrally. Further, the rotation of the first driven gear 17 is transmitted to the second driven gear 22, and the driven gear 22, the shaft 21, and the weight 24 rotate integrally. Due to the rotation of both weights 19 and 24, a load in the direction of eliminating the inertial force or the inertial couple due to the piston, connecting rod, etc. is generated, and the load reduces the vibration of the crankshaft 3.

In addition to the basic structure described above, in this embodiment, the drive gear 10 and the driven gears 17 and 22 are each made of a material having a relatively small coefficient of thermal expansion such as iron. Further, as shown in FIGS. 1 and 4, a substantially annular flange 25 having the axis L of the crank journal 4 as its own axis is fixed to the side surface of the drive gear 10. Flange 2
Both ends of 5 are locked to the protrusion 9 a of the mounting portion 9. An annular thermal expansion body 26 as a displacing means is fitted around the outer periphery of the flange 25. The thermal expansion body 26 is formed using a material having a thermal expansion coefficient larger than that of iron forming the drive gear 10 and the driven gears 17 and 22, such as aluminum or copper.

A thin plate-shaped member 4 is formed on the outer periphery of the thermal expansion body 26.
The elastic bodies 27a, 27b, 27c, 27d of the pieces are attached respectively. Each elastic body 27a to 27d is formed using an elastic material such as rubber, soft resin, or leather. Here, each of the elastic bodies 27a to 27d corresponds to the drive gear 1
No. 0, it is attached only to four places where it is presumed that a rattling noise is generated with the first driven gear 17.

The pasting position of this gear rattling noise will be described in detail. FIG. 7 shows an internal combustion engine 1 with a balancer device 8.
5 shows the timing of generation of the top dead center determination signal, the timing of generation of rattling sound, the fluctuation of the angular acceleration of the crankshaft 3, and the fluctuation of the rotational speed of the shaft 3 when the engine is actually operated. . However, the elastic bodies 27a to 27d described above are not attached to the drive gear 10 of the balancer device 8. The top dead center determination signal is a signal detected by the sensor when each piston reaches the top dead center.

[0021] This internal combustion engine 1 has a combustion cycle consisting of four strokes, namely, an intake stroke, a compression stroke, an explosion stroke (expansion stroke) and an exhaust stroke, while the crankshaft 3 rotates twice (while it rotates 720 °). It is a so-called 4-cycle engine that executes. Further, the internal combustion engine 1 has four cylinders, and the combustion cycle of each cylinder is performed in a predetermined fixed order. Here, the timing at which the top dead center determination signal is detected is defined as the reference timing (crank angle 0 °). Then, as is clear from FIG. 7, when the fluctuation of the angular acceleration changes from an increase to a decrease (when the crank angle is 20
At 200 °, 200 °, 380 °, 560 °). Further, when the variation of the angular acceleration of the crankshaft 3 changes from a decrease to an increase (when the crank angle is 110 °, 290 °, 470 °, 650 °), a large rattle noise is generated. When the tendency of the fluctuation of the angular acceleration changes, the fluctuation of the rotation speed of the crankshaft 3 instantaneously becomes “0”.

When the tendency of the fluctuation of the angular acceleration changes as described above, it is estimated that a rattling noise is generated as follows. FIG. 9A shows a meshing state between the drive gear 10 and the first driven gear 17 when the crank angle in FIG. 7 is less than 20 °, for example. At this timing, the fluctuation amount of the angular acceleration of the crankshaft 3 is increasing, and the tooth flank 11a on the front side in the rotation direction (arrow A direction) of the drive gear 10 is the tooth flank on the rear side in the rotation direction of the first driven gear 17. 1
It is in contact with 8b. With both tooth surfaces 11a, 18b in contact with each other, the drive gear 10 and the first driven gear 17
Are rotating at the same rotation speed and the same angular acceleration.

As shown in FIG. 9 (b), the crank angle is 2
At 0 °, 200 °, 380 °, and 560 °, the fluctuation of the angular acceleration of the crankshaft 3 turns from increasing to decreasing.
At this time, the first driven gear 17 rotates by the inertial force while maintaining the angular acceleration and the rotational speed up to that point. The angular acceleration and the rotational speed of the driven gear 17 exceed those of the drive gear 10, and the tooth surface 18b of the driven gear 17 has a tooth surface 18b.
Away from the tooth surface 11a. The driven gear 17 rotates relative to the drive gear 10 by the amount of backlash between the gears 10 and 17. Then, as shown in FIG. 9C,
The tooth surface 18a on the front side in the rotation direction of the driven gear 17 is the drive gear 1
Colliding with the tooth surface 11b on the rear side in the rotation direction of 0, a tapping sound (toothing sound) is generated. Due to this collision, the angular acceleration and the rotation speed of the driven gear 17 decrease.

Crank angles are 110 °, 290 °, 470
9 °, 650 °, when the fluctuation of the angular acceleration of the drive gear 10 starts to decrease and then increases, and the same angular acceleration and rotational speed exceed those of the driven gear 17, as shown in FIG. 10 is the tooth surface 11b of the driven gear 17 is tooth surface 18a.
Away from. Drive gear 10 by the amount of backlash
Rotates relative to the driven gear 17. Then, as shown in FIG.
As shown in (a), the tooth surface 11a on the front side in the rotational direction of the drive gear 10 collides with the tooth surface 18b on the rear side in the rotational direction of the driven gear 17, and a hammering sound (teeth hammering sound) is generated.

In order to prevent the occurrence of such rattling noise, the driven gear 1 is used when the tendency of the angular acceleration changes.
It suffices to impart a rotational resistance larger than that of the other timings to 7 to suppress the relative rotation of both gears 10 and 17.

From this point of view, in this embodiment, in the drive gear 10 meshing with the first driven gear 17, the elastic bodies 27a, 27b, 27 are arranged at four places where the rattling noise is supposed to be generated.
c and 27d are attached respectively. More specifically, the crank angle when the projection 9a of the mounting portion 9 of the drive gear 10 reaches the uppermost position (the 12 o'clock position) is set as a reference crank angle (0 °) for convenience of description. Then, as shown in FIG. 8A, in the drive gear 10, the driven gear 1 has crank angles of 20 °, 380 °, and 740 °.
An elastic body 27a is attached to a portion that meshes with 7. As shown in FIG. 8B, in the drive gear 10,
Driven gear 17 when the crank angle is 110 ° and 470 °
An elastic body 27b is attached to a portion that meshes with.
As shown in FIG. 8C, in the drive gear 10, an elastic body 27c is attached to a portion that meshes with the driven gear 17 when the crank angle is 200 ° and 560 °. FIG.
As shown in (d), in the drive gear 10, an elastic body 27d is attached to a portion that meshes with the driven gear 17 when the crank angle is 290 ° and 650 °. Therefore,
The angle formed by the line connecting the adjacent elastic body and the axis L with respect to the line connecting the predetermined elastic body and the axis L is about 90 °.

Further, when the thermal expansion body 26 contracts (FIG. 5), the elastic bodies 27a to 27d do not contact the teeth 18 of the driven gear 17, and when the thermal expansion body 26 expands (FIG. 6), the elastic bodies 27a to 27d do not contact the teeth 18 of the driven gear 17. The thicknesses of the thermal expansion body 26 and the elastic bodies 27a to 27d are set so that the teeth 27a to 27d are brought into pressure contact with the teeth 18 to impart rotational resistance. And each elastic body 27a-27
Reference numeral d denotes a rotation resistance applying unit that applies more rotation resistance to the driven gear 17 than other timings in accordance with the timing of change in the angular acceleration that periodically occurs in the drive gear 10.

Next, the operation and effect of this embodiment configured as described above will be described. FIG. 5 shows a state of the balancer device 8 when the temperature of the engine itself including the temperature of the cooling water, the temperature of the lubricating oil and the like is low (when it is cold) at the time of starting the internal combustion engine 1. With the operation of the internal combustion engine 1,
When the drive gear 10 rotates integrally with the crankshaft 3, the rotation is transmitted to the first driven gear 17 meshed with the gear 10. This transmission causes the driven gear 17 to rotate.

At this time, since the thermal expansion body 26 is contracted, the elastic bodies 27a to 27 are accompanied by the rotation of the drive gear 10.
Even when d moves to a position corresponding to the driven gear 17, the elastic bodies 27a to 27d do not contact the teeth 18 of the driven gear 17. The drive gear 10 and the driven gear 17 are meshed with each other with a predetermined backlash occurring between the teeth 11 and 18.

In such a cold state, it should be prioritized that the friction is reduced rather than suppressing the generation of rattling noise due to backlash. That is, since the viscosity of the lubricating oil is high during cold, the friction of various shafts for transmitting the driving force is large. Therefore, the drive gear 10 and the driven gear 17
The relative rotation between them is small and the rattling noise is originally low. If the teeth 18 of the driven gear 17 are configured to come into contact with the elastic bodies 27a to 27d even in this situation, the contact adds a rotational resistance to the driven gear 17 and increases the drive torque of various shafts. To do. Along with this, the load on the internal combustion engine 1 increases, which leads to a reduction in fuel consumption.

On the other hand, in this embodiment, the elastic bodies 27a to 27d do not come into contact with the teeth 18 of the driven gear 17 during the cold state, and unnecessary rotation resistance is not applied to the driven gear 17. Therefore, it is possible to suppress an increase in load and prevent a decrease in fuel consumption.

When the temperature of the engine itself including the temperature of the cooling water and the temperature of the lubricating oil rises (is warmed up) in accordance with the operation of the internal combustion engine 1, the thermal expander 26 expands as shown in FIG. The elastic bodies 27a to 27d are pushed outward in the radial direction. When the elastic bodies 27a to 27d move to a position corresponding to the driven gear 17 with the rotation of the drive gear 10, the elastic body 2a
7a to 27d come into contact with the teeth 18 of the driven gear 17.

When the internal combustion engine 1 is warmed up and warmed up, the viscosity of the lubricating oil is smaller than when it is cold, and the friction of various shafts for transmitting the driving force is small. Therefore, the relative rotation amount between the drive gear 10 and the driven gear 17 is likely to be larger than that in the cold state.

On the other hand, as described above, in the internal combustion engine 1, the angular acceleration of the crankshaft 3 (driving gear 10) periodically fluctuates due to the combustion cycle. Therefore, at the timing when the tendency of fluctuation changes, the gears 1 and 2 are caused by the backlash existing between the teeth 11 and 18.
0 and 17 rotate relative to each other, and tooth surfaces (11a, 18b), (1
1b, 18a) Competitors come into contact with each other, and a rattling noise easily occurs.

However, in the present embodiment, the position where the tendency of the fluctuation of the angular acceleration in the drive gear 10 changes (the crank angle is 2
0 °, 110 °, 200 °, 290 °, 380 °, 47
Elastic bodies 27a to 27d are respectively attached to 0 °, 560 °, 650 °, 740 °). These four pieces of elastic bodies 27a to 27d are intermittently pressed against the teeth 18 of the driven gear 17, and more rotational resistance is applied to the driven gear 17 than at other timings. By this rotation resistance,
Relative rotation of the driven gear 18 with respect to the drive gear 10 is suppressed. As a result, the tooth flanks (11
a, 18b), (11b, 18a) contact with each other is prevented or suppressed.

On the contrary, at the timing when the tendency of the fluctuation of the angular acceleration does not change, the rotation resistance by the elastic bodies 27a to 27d becomes smaller (in this case, becomes zero) compared to the timing when the tendency of the change of the angular acceleration does not change. Therefore, in the present embodiment, the increase in friction due to the addition can be reduced as compared with the conventional technique in which the annular elastic body is brought into pressure contact with the output side gear to constantly give the rotation resistance.

As described above, according to the present embodiment, at the timing at which it is estimated that the rattling noise is generated due to the tendency of the fluctuation of the angular acceleration, the prevention of the rattling noise is prioritized over the reduction of the friction. . Therefore, it is possible to impart rotation resistance to the driven gear 17, suppress relative rotation of the drive gear 10 and the driven gear 17, and prevent generation of rattling noise. Further, since it is not necessary to prevent the rattling noise from occurring at the timing when the tendency of the fluctuation of the angular acceleration does not change, the elastic body 27
The rotation resistance is not given to the driven gear 17 by a to 27d. For this reason, it is possible to prevent an unnecessary increase in friction associated with imparting rotational resistance, and prevent deterioration of fuel efficiency.

Further, in this embodiment, the drive gear 10 having a diameter larger than that of the driven gear 17 is connected to the thermal expansion body 26 and the elastic bodies 27a to 27a.
27d is attached. Therefore, these members 26,
Compared with the case where the driven gear 17 having a small diameter is provided with 27a to 27d, the thermal expansion effect of the thermal expansion body 26 can be sufficiently brought out, and it is possible to respond to the temperature change sensitively.

Further, in this embodiment, the elastic bodies 27a to 27d are attached to the drive gear 10, and the driven gear 17 is brought into pressure contact with the driven gear 17 only when the tendency of fluctuation of the angular acceleration of the gear 10 is changed to impart the rotational resistance. I have to. Therefore, as compared with the case where a member other than the elastic bodies 27a to 27d is used as the rotation resistance applying unit, it is possible to prevent the rattling noise from occurring and suppress an increase in friction with a simple configuration. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the crankshaft 3, the drive gear 1
The drive roller 28 is fixed to a position different from 0.
The drive roller 28 is rotated integrally with the crankshaft 3 about the axis L of the crank journal 4. First
A driven roller 29 is fixed to the shaft 16 of the balance shaft 15 at a position corresponding to the drive roller 28.

An annular thermal expansion body 30 made of a material having a larger thermal expansion coefficient than iron such as aluminum and copper is attached to the outer periphery of the drive roller 28. Four pieces of thin plate-shaped elastic bodies 31 are provided on the outer periphery of the thermal expansion body 30 at positions (same rotation phase) corresponding to the positions where the elastic bodies 27a to 27d are attached in the drive gear 10 of the first embodiment. It is pasted. Further, an annular elastic body 32 is fitted around the outer periphery of the driven roller 29. The thermal expansion body 26 and the elastic bodies 27a to 27d on the drive gear 10 are omitted.

When the thermal expansion body 30 is contracted, the elastic body 31 on the outer periphery of the drive roller 28 is moved by the driven roller 2
It is set so that it does not come into contact with the elastic body 32 on the outer periphery of 9. When the thermal expansion body 30 is expanded, the elastic body 31 on the outer periphery of the drive roller 28 is pushed outward in the radial direction by the expansion action of the thermal expansion body 30, and the elastic body 31 is elastic on the outer periphery of the driven roller 29. It is adapted to be pressed against the body 32.

When the elastic members 31 and 32 are pressed against each other, the elastic member 31 is moved from the center of rotation of the drive roller 28.
The ratio of the distance to the outer surface and the distance from the rotation center of the driven roller 29 to the outer peripheral surface of the elastic body 32 (radius ratio) is equal to the ratio of the radius of the drive gear 10 and the radius of the driven gear 17 (gear ratio). Is set to.

Next, the operation and effect of the second embodiment having the above structure will be described. The thermal expansion body 30 contracts when the internal combustion engine 1 is cold. Therefore, even if each elastic body 31 moves to a position corresponding to the driven roller 29 as the drive roller 28 rotates, the elastic body 31 does not contact the elastic body 32 on the outer periphery of the driven roller 29. Drive gear 10 and driven gear 1
The teeth 7 and 7 are meshed with each other with a predetermined backlash occurring between the teeth 11 and 18.

Since the viscosity of the lubricating oil is high during such a cold state, the friction of various shafts for transmitting the driving force is large. Therefore, the relative rotation between the drive gear 10 and the driven gear 17 is small, and the rattling noise is originally small.
If the elastic body 32 on the outer periphery of the driven roller 29 is configured to contact the elastic body 31 on the outer periphery of the drive roller 28 even under this condition, the contact causes a rotational resistance to the driven gear 17 and various shafts. Drive torque increases. Along with this, the load on the internal combustion engine 1 increases, which leads to a reduction in fuel consumption.

On the other hand, in the present embodiment, the elastic bodies 31 and 32 do not come into contact with each other during the cold state, and unnecessary rotation resistance is not applied to the driven gear 17. Therefore, it is possible to suppress an increase in load and prevent a decrease in fuel consumption.

When the internal combustion engine 1 is warmed up in accordance with the operation of the internal combustion engine 1, the thermal expansion body 30 expands and the elastic body 31 is pushed outward in the radial direction. When the elastic body 31 moves to the rotational phase corresponding to the position where the rattling noise is estimated to occur as the drive gear 10 rotates, the elastic body 31 comes into contact with the elastic body 32 on the outer circumference of the driven roller 29.

When the internal combustion engine 1 is warmed up and warmed up, the viscosity of the lubricating oil is smaller than when it is cold, and the friction of various shafts for transmitting the driving force is small. Therefore, the relative rotation amount between the drive gear 10 and the driven gear 17 is likely to be larger than that in the cold state.

On the other hand, as described above, in the internal combustion engine 1, the angular acceleration of the crankshaft 3 (driving gear 10) periodically fluctuates due to the combustion cycle. Therefore, at the timing when the fluctuation tendency changes, the gears 10 and 17 relatively rotate due to the backlash existing between the teeth 11 and 18, and the tooth surfaces (11a, 18b) and (11b, 18a) come into contact with each other. Dental noise is likely to occur.

However, in the present embodiment, the gear ratio of the drive gear 10 and the driven gear 17 is equal to the radius ratio of the drive roller 28 and the driven roller 29, so that the drive roller 2
The elastic body 31 on the outer periphery of 8 comes into pressure contact with the elastic body 32 of the driven roller 29, and more rotational resistance is applied to the driven gear 17 than at other timings. By this addition, the drive gear 10
The relative rotation of the driven gear 17 with respect to is suppressed. Along with this, the tooth surfaces (11a, 18) of both gears 10, 17 are
b) and (11b, 18a) contact with each other is prevented or suppressed.

On the contrary, at the timing when the tendency of the fluctuation of the angular acceleration does not change, the rotation resistance by the elastic body 31 becomes smaller (in this case, becomes zero) compared to the timing when it changes. For this reason, compared with the case where a ring-shaped elastic body is attached to the outer periphery of the driving roller 28 and is pressed against the elastic body 32 on the outer periphery of the driven roller 29 to constantly impart rotational resistance, the present embodiment is caused by the same provision. It is possible to suppress unnecessary increase in friction.

Further, in this embodiment, the driving roller 28 having a diameter larger than that of the driven roller 29, the thermal expansion body 30 and the elastic body 31 are provided.
Is installed. Therefore, as compared with the case where these members 30 and 31 are provided on the driven roller 29 having a small diameter, the thermal expansion member 3
It is possible to sufficiently bring out the thermal expansion effect of 0, and it is possible to respond sensitively to temperature changes.

Further, in this embodiment, since the driving roller 28 and the driven roller 29 are arranged at positions different from those of the driving gear 10 and the driven gear 17, both rollers 28, 29 are arranged.
Can be placed in an environment where the temperature changes drastically. Under this environment, the change due to the thermal expansion of the thermal expansion body 30 becomes significant, and thus it is possible to more quickly respond to the temperature change.

In this embodiment, the elastic body 3 is attached to the drive roller 28.
1, the elastic body 31 is brought into pressure contact with the driven roller 29 only when the tendency of fluctuation of the angular acceleration of the drive gear 10 is changed, so that the driven gear 17 is given a rotational resistance. Therefore, as compared with the case where a member other than the elastic body 31 is used as the rotation resistance imparting means, it is possible to prevent the generation of rattling noise and suppress an increase in friction with a simple configuration.

The present invention can be embodied in another embodiment shown below. (1) As the rotation resistance imparting means, elastic bodies 27a to 27 are used.
The following can be used instead of d and 31. That is, the temperature of the lubricating oil of the internal combustion engine 1, the input shaft (first and second
In the embodiment, the rotation fluctuation of the crankshaft 3), the rotation fluctuation of the output shaft (the shaft 16 of the first balance shaft 15 in the first and second embodiments) and the like are electrically detected. A member for estimating the timing at which gear rattling noise is generated based on the detected value and, when the timing arrives, restricting the rotation of the gear on the side surface of either one of the gears (driving gear 10 or driven gear 17). To press. Even in this case, the same operation and effect as those of the first and second embodiments can be obtained.

(2) In the first and second embodiments, when the combustion cycle of the internal combustion engine 1 changes the tendency of the angular acceleration in the drive gear 10, the driven gear 17 is given more rotational resistance. In addition to this, when the angular acceleration of the drive gear 10 changes due to deterioration of the lubricating oil or wear of the teeth 11 and 18 of the gears 10 and 17, for example, the rotational resistance is larger than that before the timing. May be added to the driven gear 17.

(3) The present invention can be embodied not only in the balancer device 8 of the internal combustion engine 1 described above, but also in a gear device of a type in which the angular acceleration of the gear on the input side or the output side periodically fluctuates. . For example, in a gear device that is interposed between a main shaft and a motor that drives the shaft in a loom, the load applied to the main shaft fluctuates due to the reciprocating motion of a reed, etc. Acceleration fluctuates periodically. Therefore, also in this case, by providing a rotation resistance imparting means such as an elastic body, it is possible to prevent the rattling noise from occurring and suppress an increase in friction.

The present invention can also be applied to a gear device in which a non-constant velocity joint (hook type joint) is interposed in the drive force transmission path. The hook type joint is composed of an input side yoke attached to the input shaft, an output side yoke attached to the output shaft, and a cross shaft connecting both yokes. In this joint, even if the rotation speed of the input shaft is constant, the rotation speed of the output shaft changes twice per rotation. This fluctuation increases as the angle formed by both axes increases. If a gear on the input side is attached to this output shaft, the angular acceleration of the gear changes periodically. Therefore, if the gear on the output side is meshed with the gear on the input side and the rotation resistance imparting means such as an elastic body is provided, the increase in friction can be suppressed while preventing the generation of rattling noise.

Furthermore, the present invention can be embodied as a gear device for a transmission (transmission) or a machine tool. (4) Thermal expansion body 26 and elastic body 27 in the first embodiment
a to 27d are replaced by the first driven gear 1 instead of the drive gear 10.
7 may be provided. In addition, these thermal expansion bodies 26, 27
It suffices that a to 27d are provided in at least one place of the drive transmission system, and may be provided in the second driven gear 22, for example. In particular, it is preferable to provide between the gears close to the drive source as in each of the above-described embodiments from the viewpoint of reducing the load on the drive source, and it is optimal to provide all between the gears.

(5) In the second embodiment, the elastic bodies 31 and 32 are provided on the driving roller 28 and the driven roller 29, respectively. However, only one of the rollers 28 and 29 may be provided with an elastic body.

(6) As the thermal expansion bodies 26 and 30, other than aluminum and copper, a shape memory alloy or a shape memory resin may be used. (7) Instead of the thermal expansion bodies 26 and 30 in the first and second embodiments, the gears 10 and 17 themselves (the roller 2
(8, 29 itself) or its surrounding temperature, and mechanically elastic bodies 27a to 27d, 31 are detected according to the detected temperature.
You may provide the mechanism which displaces.

(8) In the first and second embodiments, the annular thermal expansion bodies 26 and 30 are used, but these are elastic bodies 27a to 27.
You may change into a small piece according to the shape of d and 31. Moreover, these thermal expansion bodies 26 and 30 may be omitted.

(9) Elastic body 27a in the first embodiment
27d may be attached to the drive gear 10 at a position other than the side surface. For example, an annular groove is formed on the outer periphery of the drive gear 10 and / or the first driven gear 17, and the elastic body 2 is formed therein.
7a-27d may be attached.

(10) The elastic body in the first and second embodiments is formed in an annular shape, and the thickness of the elastic body in the drive gear 10 where the tendency of the fluctuation of the angular acceleration changes is made larger than that in the other places. Good. Even in this case, according to the variation timing of the angular acceleration periodically generated in the drive gear 10,
More rotation resistance can be applied to the driven gear 17 than at other timings.

Although the respective embodiments of the present invention have been described above, technical ideas other than the claims which can be understood from the respective embodiments will be described below together with their effects. (A) In the gear device according to claim 1, the rotation resistance imparting means is attached to the gear on the input side or the output side, and only when the tendency of fluctuation of the angular acceleration of the gear changes. A gear device, which is an elastic body that is pressed against a gear on the input side to impart rotational resistance. With this configuration, it is possible to prevent the rattling noise with a simple configuration and suppress an increase in friction.

(B) In the gear device according to claim 1 or (a), the gear on the input side is integrally rotatably attached to a crankshaft whose angular acceleration varies in synchronization with a combustion cycle of an internal combustion engine. Gear device that has been created.
According to this configuration, the angular acceleration of the crankshaft fluctuates in synchronization with the combustion cycle of the internal combustion engine, but it is possible to reliably prevent rattling noise between gears due to this fluctuation. Further, it is possible to prevent an unnecessary increase in friction and prevent deterioration of fuel efficiency of the internal combustion engine.

(C) In the gear device described in (b) above, the gears on the input side and the output side constitute a part of a balancer device for damping the vibration of the crankshaft of the internal combustion engine. The gear on the side is connected to the vibration damping weight, and is meshed with the gear on the input side. With this configuration, the vibration of the crankshaft can be damped while preventing the rattling noise and the increase in friction.

(D) In the gear device described in (b) above, when the internal combustion engine is in a low temperature state, the elastic body is separated from the teeth of the gear on the input side or the output side, and in the high temperature state, the elastic body is A gear device provided with a displacing means for displacing an elastic body in a radial direction of a gear according to a temperature so as to be pressed against a tooth.
This is because when the internal combustion engine is in a low temperature state, the viscosity of the lubricating oil is large, and the friction of various shafts for transmitting the driving force is large. The relative rotation of both gears is small and the rattling noise is originally low. This is because, at this time, it is considered more important to suppress the increase in friction than to suppress the generation of rattling noise. According to this configuration (d), when the internal combustion engine is at a low temperature, the elastic body does not come into contact with the counterpart gear due to the action of the displacement means. Therefore, it is possible to suppress an increase in friction caused by the contact of the elastic body.

(E) In the gear device described in (d) above, the displacement means is made of a material having a coefficient of thermal expansion larger than those of both gears, and the center of rotation of the gear on the side to which the elastic body is attached. Is a thermal expansion body arranged on a circle centered on, and the elastic body is a gear unit attached to the thermal expansion body. In this way, the thermal expansion body automatically contracts or expands according to the temperature of the internal combustion engine, and the volume changes,
The elastic body can be displaced in the radial direction of the gear with a simple structure.

(F) In the gear device according to the above (e), the thermal expansion body is provided on one of the input-side gear and the output-side gear having the larger outer diameter.
According to this structure, the thermal expansion effect of the thermal expansion body can be sufficiently brought out and the temperature change can be responded sensitively, as compared with the case where the thermal expansion body is provided in the gear having a small diameter.

(G) In the gear device according to the first aspect, the rotation resistance imparting means is a pair of rollers provided so as to correspond to the shafts of the respective gears, and one of the rollers is attached to the gears. A gear unit including an elastic body that presses against the other roller to impart rotational resistance only when the change in the angular acceleration of the other changes. With this configuration, it is possible to prevent the rattling noise with a simple configuration and suppress an increase in friction.

(H) In the gear device described in (g) above, the input side gear is integrally rotatably attached to a crankshaft whose angular acceleration fluctuates in synchronization with the combustion cycle of the internal combustion engine. Displacement means for displacing the elastic body in the radial direction of one roller in accordance with the temperature so that the elastic body separates from the other roller when the engine is in a low temperature state, and the elastic body presses against the roller when the engine is in a high temperature state. Gear device provided with. According to this configuration, the elastic body does not come into contact with the counterpart gear due to the action of the displacing means when the internal combustion engine is at a low temperature, as in the above-mentioned (d). Therefore, it is possible to suppress an increase in friction caused by the contact of the elastic body. Furthermore, since both rollers are arranged at positions different from those of both gears, both rollers can be arranged in an environment where the temperature changes drastically.

In this specification, the members relating to the constitution of the invention are defined as follows. (A) The input-side and output-side gears are members that transmit rotational force between the two shafts, and the two shafts are parallel to each other (spur gears, helical gears, Yamaba gears, etc.), and the two shafts intersect each other. Includes gears (sugbakasa gears, helical gears, crown gears, etc.), two shafts with different axes (screw gears, hypoid gears, etc.), and special gears (non-circular gears).

(B) The elastic body means a member which is elastically deformed when it corresponds to the teeth of the gear and imparts rotational resistance to the teeth,
In addition to the one made entirely of an elastic material, the one having a hollow inside and the one having a hollow portion filled with a fluid such as gas or liquid are included.

[0075]

As described in detail above, according to the present invention, more rotational resistance is given to a gear at a timing at which gear rattling noise is estimated to occur than at other timings. Therefore, it is possible to suppress the generation of gear rattling noise, prevent unnecessary friction from increasing, and reduce energy loss.

[Brief description of drawings]

FIG. 1 is a front view showing a positional relationship between a drive gear and both driven gears in a balancer device of an internal combustion engine in a first embodiment embodying the invention.

FIG. 2 is a front view showing a cylinder block and a balancer device of an internal combustion engine.

FIG. 3 is a side view showing a crankshaft and a balancer device.

FIG. 4 is a cross-sectional view showing a meshed state of a drive gear and a first driven gear.

FIG. 5 is a partial front view showing a state in which the drive gear and the first driven gear mesh with each other when the internal combustion engine is cold.

FIG. 6 is a partial front view showing a state in which the drive gear and the first driven gear mesh with each other after the internal combustion engine is warmed up.

FIG. 7 is a timing chart showing a correspondence relationship between a top dead center determination signal, a rattling sound, a change in angular acceleration of a crankshaft, and a change in rotational speed.

FIG. 8A to FIG. 8D are front views illustrating a correspondence relationship between a drive gear and both driven gears.

9A to 9D are partial cross-sectional views illustrating a phenomenon in which a rattling noise is generated and showing a meshed state of a drive gear and a first driven gear.

FIG. 10 is a cross-sectional view showing a positional relationship between a driving gear, a first driven gear, a driving roller and a driven roller in the second embodiment of the present invention.

[Explanation of symbols]

10 ... Drive gear as input side gear, 17 ... First driven gear as output side gear, 27a, 27b, 27
c, 27d, 31 ... An elastic body as a rotation resistance imparting means.

Claims (1)

[Claims] 1. An output gear according to an input-side gear, an output-side gear meshed with the input-side gear, and a variation timing of angular acceleration periodically generated in the input-side or output-side gear. A gear device provided with a rotation resistance imparting means for imparting more rotation resistance to a gear on the input side or the input side than at other timings.