JPH09296858A - Gear pair and fluid mechanism using gear pair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent tooth hitting sound of a gear pair. SOLUTION: A gear pair is provided with gears 65, 67 to be meshed with each other, a friction gear 69 having the number of teeth different from the gear 65 and engaged with the gear 67 coaxially with the gear 65, a belleville spring 71 for pressing the tooth surface of the friction gear 69 to the gear 65 in a state where the tooth face is displaced in the rotational direction by the adjustment of backlash, and adjusting the backlash of the gears 65, 67 to a value smaller than that of the initial backlash, and a centrifugal, weight 73 fixed to the outer edge of the belleville spring 71, for reducing pressing force of the belleville spring 71 in the high-speed rotation, enabling the gear 69 to be rotated and displaced in relation to the gear 65, and returning the backlash to the initial backlash.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear set and a fluid machine using this gear set.

[0002]

2. Description of the Related Art A screw type or roots type compressor is used for a vehicle supercharger. In these compressors, a timing gear set is used to rotate a pair of rotors synchronously and mesh with each other so that they do not come into contact with each other. Various gear sets are used.

However, when the engine rotates at a low speed with a light load, such as during idling, the torque tends to fluctuate. When the torque fluctuates, backlash causes tooth flanks to repeatedly collide with each other at the meshing portion of the gear set. Sound is generated.

Since the engine noise is low when the engine rotates at low speed, this rattling noise becomes a serious problem.

Further, since a gear set which produces a rattling noise repeats fine movements in the rotating direction, when such a gear set is used as a timing gear set of a fluid machine, fluctuations in the clearance between rotors and rotor hits occur. , There is a possibility that performance and durability may be deteriorated.

In order to prevent gear rattling noise, there are a method of using a scissors gear and a friction gear in a gear set, a method of meshing gears by reducing backlash.

The gear set 201 shown in FIGS. 9 and 10 is described in "Automotive Technology Handbook Second Volume Design Edition P216 Japan Society of Automotive Engineers, issued March 1, 1991", and is of a friction gear type. It is a gear set.

As shown in FIG. 9, this gear set 201 includes a main drive gear 203 and a counter drive gear 205.
And a friction gear 207 and a spring 209. The friction gear 207 is arranged on the shaft 211 so as to be rotatable relative to the counter drive gear 205, and is pressed against the side surface of the counter drive gear 205 by a spring 209.

The number of teeth of the friction gear 207 is different from that of the counter drive gear 205 by one, and the friction gear 207 meshes with the main drive gear 203 together with the counter drive gear 205.

While the friction gear 207 and the counter drive gear 205 mesh with the main drive gear 203, they are respectively indicated by solid arrows 213 and 21 in FIG.
When rotating in the direction of 5, a difference in the number of teeth is generated between the friction gear 207 and the counter drive gear 205, and this difference in rotation causes the friction gear 207 and the counter drive gear 205 to be different, as indicated by a broken arrow 217. A frictional force is generated on the sliding surface 219. This friction force rotates the friction gear 207, cancels backlash between the main drive gear 203 and the counter drive gear 205, and prevents rattling noise.

[0011]

However, in the gear set 201 of the friction gear type, the friction gear 207 is used.
The driving force loss due to only the frictional force between the counter drive gear 205 and the counter drive gear 205 occurs, and the power transmission efficiency and the fuel consumption of the prime mover decrease.

Also in the scissors gear system, the power transmission efficiency is lowered due to the friction loss generated between the scissors gear and the counterpart gear. In addition, the method of reducing the backlash imposes a heavy load on the tooth flanks of the gear and the bearing that supports the gear.

Therefore, according to the present invention, the backlash is reduced in the low speed rotation range where gear rattle noise is likely to occur to prevent the gear rattle noise, and the backlash is increased in the high speed rotation range where the driving force loss becomes large. An object is to provide a gear set capable of reducing loss and a fluid machine using this gear set as a timing gear set.

[0014]

According to a first aspect of the present invention, there is provided a gear set in which a pair of gears meshing with each other with a predetermined backlash and a tooth surface of one gear are displaced in the rotational direction by an amount corresponding to the adjustment of the backlash. In the state, it meshes with the other gear and adjusts the backlash of both gears to a value smaller than the above-mentioned predetermined backlash, and the backlash adjustment gear and one of the gears hold the displacement in the rotational direction to maintain the backlash of both gears. A backlash holding member that holds the backlash at the adjustment value and a centrifugal weight are provided, and the backlash adjustment gear is moved in the axial direction by the centrifugal force of the centrifugal weight during high-speed rotation, and the backlash between one gear and the other gear is reduced. It is characterized by making it larger than that at low speed rotation.

As described above, the backlash holding member meshes with the other gear while the tooth surface of the backlash adjusting gear is displaced in the rotational direction from the tooth surface of the one gear by the amount of the backlash adjustment. The backlash between the gear and the other gear is maintained at an adjustment value smaller than the initial value (predetermined value).

When the rotational speed increases, the backlash adjusting gear moves in the axial direction due to the centrifugal force of the centrifugal weight, and the backlash adjusting function disappears. One gear and the other gear are adjusted at low speed. Engages with a backlash that is greater than the specified value.

Therefore, during low-speed rotation, gear rattle between gears can be prevented and torque loss can be prevented and smooth torque transmission can be performed even if torque fluctuation occurs due to light load. .

Further, since no rattling noise is produced, quietness is maintained even when the engine is running at low speed and has low noise.

As the number of revolutions increases, the backlash adjusting function of the backlash adjusting gear disappears, the friction with one or the other gear is reduced, and the backlash of the one and the other gear increases, so that the backlash adjusting gear has a larger backlash. As a result, the power transmission efficiency and the fuel economy of the prime mover are improved. Further, by increasing the backlash in this way in the high-speed rotation region where the driving force loss due to friction increases, the effect of improving the power transmission efficiency and the fuel consumption becomes particularly large.

Further, since torque fluctuations are less likely to occur during high speed rotation, gear rattle does not occur even if the backlash between gears is increased.

Further, basically, since the backlash of the one and the other gears is not forcibly reduced, the load on each gear and the bearings supporting each gear is greatly reduced and the durability is improved.

The pair of gears and the backlash adjusting gear may have external teeth or internal teeth.

According to a second aspect of the present invention, in the gear set according to the first aspect, the backlash adjusting gear has a number of teeth different from that of one gear and is rotatable relative to the one gear. The backlash holding member is a spring that presses the backlash adjusting gear against one gear and holds the displacement in the rotational direction between the backlash adjusting gear and the one gear by the frictional force. By reducing the pressing force of, the backlash adjusting gear can be rotationally displaced with respect to one gear at the time of high speed rotation, and the backlash is made larger than that at the time of low speed rotation.

As described above, in the gear set according to the second aspect, since the number of teeth of the backlash adjusting gear is different from that of the one gear, the backlash adjusting gear and the one gear are rotated when meshing with the other gear. There is a rotation difference between the two gears, and this rotation difference presses the tooth flank of the backlash adjusting gear against the tooth flank of the other gear. In this way, the backlash between the one gear and the other gear is absorbed, and the spring presses the backlash adjusting gear against the one gear to generate a frictional force, and this frictional force generates the backlash adjusting gear and the one gear. Hold and in the backlash absorption position.

When the number of rotations increases, the centrifugal force of the centrifugal weight reduces the pressing force and frictional force of the spring, and the backlash adjusting gear can be rotationally displaced with respect to one gear, and the backlash of the backlash adjusting gear is reduced. Since the adjustment function disappears, the backlash of one gear and the backlash of the other returns to an initial value that is larger than the adjustment value during low speed rotation.

Therefore, in the gear set according to the second aspect, similarly to the configuration of the first aspect, gear rattling noise between gears is prevented and torque loss occurs during low speed rotation even if torque fluctuation occurs. Since the torque can be prevented from being transmitted smoothly and no rattling noise is generated, quietness is maintained even when the engine is running at low speed and has low noise.

Further, when the number of revolutions increases, the friction between the backlash adjusting gear and one gear is reduced, and the power transmission efficiency and the fuel consumption of the prime mover are improved as compared with the conventional example.

In addition to these, the same effect as the structure of claim 1 is obtained.

According to a third aspect of the present invention, in the gear set according to the second aspect, the spring is a disc spring that presses the backlash adjusting gear against one gear, and the centrifugal weight is fixed to the disc spring. The pressing force of the disc spring is reduced by the centrifugal force, and an effect equivalent to that of the configuration of claim 2 is obtained.

In addition to this, by integrating the centrifugal weight and the disc spring, the number of parts can be reduced and
The space for disposing the centrifugal weight and disc spring can be small.

The invention according to claim 4 is the gear set according to claim 1, wherein the number of teeth of the backlash adjusting gear is the same as the number of teeth of one gear, and the backlash holding member is the backlash adjusting gear. Is a positioning member that positions the tooth flanks of one gear in the rotational direction by displacing the tooth flanks in the rotational direction by the amount of backlash adjustment.The centrifugal weight moves the backlash adjustment gear in the axial direction during high-speed rotation. It is characterized in that the backlash between one gear and the other gear is made larger than that at the time of low speed rotation.

As described above, the backlash adjusting gear and the one gear are positioned in the rotating direction by the positioning member in a state in which each tooth surface is displaced in the rotating direction by the amount corresponding to the adjustment of the backlash. In this way, the backlash between one gear and the other gear is made by meshing with the other gear while the tooth surface of the backlash adjusting gear is displaced in the rotational direction from the tooth surface of one gear by the amount of backlash adjustment. The adjusted value smaller than the predetermined value is held.

When the number of rotations increases, the backlash adjusting gear moves in the axial direction under the centrifugal force of the centrifugal weight, and the backlash between the backlash adjusting gear and the other gear increases. In this way, the backlash adjusting function of the backlash adjusting gear disappears, so that one gear and the other backlash return to the initial values larger than the adjustment values at the time of low speed rotation.

Therefore, in the gear set according to the fourth aspect, as in the case of the first aspect, gear rattling noise between gears is prevented and torque loss occurs during low speed rotation even if torque fluctuation occurs. Since the torque can be prevented from being transmitted smoothly and no rattling noise is generated, quietness is maintained even when the engine is running at low speed and has low noise.

When the number of revolutions increases, the backlash adjusting gear and one gear mesh with the other gear with a backlash larger than the adjustment value, so that the friction between the backlash adjusting gear and one gear and the other gear is reduced. The power transmission efficiency and the fuel economy of the prime mover are improved as compared with the conventional example.

In addition to these, the same effect as the structure of claim 1 is obtained.

According to a fifth aspect of the present invention, in the gear set according to the fourth aspect, the backlash adjusting gear has a circumference of a flexible flange member having an inclination angle with respect to a plane perpendicular to the rotation axis. This backlash adjusting gear and the flexible flange member are provided as a centrifugal weight, and the backlash adjusting gear moves in the axial direction during high-speed rotation, and the backlash between one gear and the other gear during low-speed rotation. It is characterized in that it is made larger, and an effect equivalent to that of the configuration of claim 4 is obtained.

In addition to this, since the backlash adjusting gear is formed on the peripheral portion of the flexible flange member inclined from the plane perpendicular to the rotation axis, the backlash adjusting gear and the flexible flange member are centrifugally separated. Since it functions as a weight, there is no need to provide a centrifugal weight separately,
The number of parts is reduced and the space for arrangement is small.

According to a sixth aspect of the fluid machine, a pair of rotors meshing with each other and each rotor are rotatably contained, and a fluid inlet provided on the meshing start side of each rotor and a meshing end side of each rotor. A casing having a provided fluid outlet, and a timing gear set that synchronizes the rotors and meshes with each other without contacting each other, the timing gear set according to any one of claims 1 to 5. It is characterized by the described gear set.

As described above, in the gear set according to any one of claims 1 to 5, gear rattling noise is prevented in a low rotation range, and fine movement in the rotational direction that causes the gear rattling noise occurs. Since it does not occur, if these gear sets are used for the timing gear set of the fluid machine as in the structure of claim 6, fluctuations and hits of the rotor clearance are prevented, and the efficiency and durability of the fluid machine are improved. At the same time, quietness is maintained even when the engine rotates at low speed.

In the high speed rotation range, the backlash of the timing gear set is widened, and the power transmission efficiency and the fuel consumption of the prime mover are improved. In addition, since torque fluctuation is less likely to occur during high speed rotation, gear rattle does not occur even if the backlash is increased compared to during low speed rotation.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. This embodiment is claim 1,
The supercharger 1 has the features of 2, 3 and 6 and FIG. 1 shows a supercharger 1 using this embodiment. The left and right directions are the left and right directions in each of these figures, and members and the like without reference numerals are not shown.

As shown in FIG. 1, the supercharger 1 is
Input pulley 3, electromagnetic clutch 5, timing gear set 7
(Gear set of the embodiment), screw compressor 9
(The fluid machine of the embodiment) and the like.

The input pulley 3 is supported by a compressor casing 13 (casing) by a bearing 11. The input pulley 3 is connected to a pulley on the crankshaft side via a belt, and is rotationally driven by the driving force of the engine.

The electromagnetic clutch 5 comprises an electromagnetic coil 15 and its lead wire 17, a yoke 19 of the electromagnetic coil 15, a magnetic circuit 21, an armature 23, a spring 25, a flange member 27 and the like.

The yoke 19 is fixed to the casing 13, the magnetic circuit 21 is formed by incorporating a magnetic metal into the input pulley 3, and the magnetic force of the electromagnetic coil 15 is applied to the armature 23.
Lead to.

The armature 23 has a spring 25 and screws 29, 2.
9 and is connected to the flange member 27. The boss portion 31 of the flange member 27 is spline-connected to the rotor shaft 33 on the input side, and is fixed by a bolt 35 and a washer 37.

When the electromagnetic coil 15 is excited, the spring 25
The armature 23 is bent and the magnetic circuit 21 of the input pulley 3 is bent.
And the rotation of the engine is transmitted to the rotor shaft 33. When the excitation of the electromagnetic coil 15 is stopped, the armature 23 is separated from the input pulley 3 by the force of the spring 25, and the rotor shaft 33 is separated from the engine.

Thus, the electromagnetic clutch 5 connects and disconnects the engine and the supercharger 1.

A collar 39 is attached to the rotor shaft 33,
A seal 41 is provided between the collar 39 and the casing 13.
Is arranged to prevent oil leakage to the outside of the casing 13.

The compressor 9 includes male and female screw rotors 43 and 45. The male screw rotor 43 is constructed by press-fitting the rotor shaft 33 into the shaft hole of the rotor body 47. The screw rotor 45 is constructed by fixing the rotor shaft 51 to the shaft hole of the rotor body 49. On the outer circumferences of the rotor bodies 47 and 49, screw-shaped tooth profiles that mesh with each other are formed.

The rotor shafts 33, 51 of the screw rotors 43, 45 are supported by the casing 13 at the left end by a ball bearing 53 and at the right end by a collar 55 and a roller bearing 57, respectively.
Further, a seal 61 is arranged between the collar 59 attached to the left end portions of the rotor shafts 33, 51 and the casing 13, and a seal 63 is arranged between the collar 55 at the right end portion and the casing 13. Prevents air leakage.

As shown in FIGS. 1 and 2, the timing gear set 7
Is composed of large-diameter and small-diameter timing gears 65 and 67, a friction gear 69 (backlash adjusting gear), a disc spring 71 (spring: backlash holding member), and a centrifugal weight 73.

The timing gears 65 and 67 mesh with each other with a predetermined backlash. The large-diameter timing gear 65 is press-fitted onto the outer circumference of the rotor shaft 33 of the male screw rotor 43, and the small-diameter timing gear 67 is connected to the rotor shaft 51 of the female screw rotor 45 via a lock mechanism 75. .

In the lock mechanism 75, the timing gear 67 is engaged with the timing gear 65 in a state where the screw rotors 43 and 45 are not in contact with each other, and then the nut 77 is tightened to attach the taper ring 79 to the timing gear 67 and the rotor shaft. The screw gears 43 and 45 are pushed in and the timing gear 67 is locked to position the screw rotors 43 and 45 in the rotational direction.

The friction gear 69 is rotatably supported on the outer periphery of the boss portion 81 of the timing gear 65 (one gear) and meshes with the timing gear 67 (the other gear). The friction gear 69 and the timing gear 65 have one tooth difference.

The disc spring 71 is axially positioned between the collar 39 and the boss portion 81, and rotates integrally with the rotor shaft 33. Further, the disc spring 71 is the friction gear 69.
Is pressed against the side surface of the timing gear 65, and as shown in FIG.
A frictional force is generated at these contact surfaces 83.

The centrifugal weight 73 is fixed to the outer edge of the disc spring 71.

Friction gear 69 and timing gear 6
Since the number of teeth is different from 5, the timing gear 6
When engaging with 7 and rotating, a rotation difference occurs between the friction gear 69 and the timing gear 65, and the tooth surface of the friction gear 69 is pressed against the tooth surface of the timing gear 67 by this rotation difference.

In this way, the friction gear 69 absorbs the backlash between the timing gear 65 and the timing gear 67, and the value is adjusted to a value smaller than a predetermined value. Further, the frictional force generated on the contact surface 83 by the pressing force of the disc spring 71 holds the friction gear 69 at the backlash absorbing position for the timing gear 65.

Further, together with the timing gear 65, the disc spring 7
When the rotational speed of 1 increases, the pressing force of the disc spring 71 decreases due to the centrifugal force of the centrifugal weight 73, and as shown in FIGS. 2 and 4, the friction gear 69 and the timing gear 65 are provided.
A gap 85 is formed between the frictional force and the frictional force, and the frictional force that holds the friction gear 69 at the backlash absorbing position disappears.

In this way, the friction gear 69 can be rotationally displaced with respect to the timing gear 65, the backlash adjusting function disappears, and the backlash of the timing gears 65 and 67 returns to a predetermined value larger than that at low speed rotation.

The driving force of the engine input from the pulley 3 is transmitted through the timing gear set 7 to the screw rotor 4
3 and 45 are rotationally driven. The driven compressor 9 pumps the intake air sucked from the intake port 87 (inflow port) provided on the right end side of each screw rotor 43, 45 to the left side in the axial direction between the screw rotors 43, 45, and installs it on the left end side. The gas is discharged from the discharge port 89 (outlet) thus formed, and the engine is supercharged.

Thus, the supercharger 1 is constructed.

As described above, in the timing gear set 7 of the supercharger 1, the backlash of each of the timing gears 65 and 67 is adjusted to a value smaller than a predetermined value in the low speed rotation range, and when the number of rotations increases, the backlash changes accordingly. Expanded to a larger predetermined value.

As described above, since the backlash is narrowed during low speed rotation of the engine such as idling, gear rattle between the timing gears 65 and 67 is prevented and torque is lost even if torque fluctuation occurs. It is possible to prevent the smooth torque transmission.

Further, since no rattling noise is produced, quietness is maintained even when the engine is running at low speed and has low noise.

When the engine speed increases, the backlash of the timing gears 65 and 67 returns to a predetermined value, and the backlash of the friction gear 69 and the timing gear 67 increases, so that the friction between the gears is reduced and the conventional gears are reduced. In comparison, the power transmission efficiency of the timing gear set 7 and the engine fuel economy are improved.

Since torque fluctuation is unlikely to occur when the engine is rotating at high speed, gear rattle does not occur even if the backlash of the timing gear set 7 is increased.

Further, by increasing the backlash in this way at the time of high speed rotation in which the driving force loss due to friction becomes large, the effect of improving the power transmission efficiency and the fuel consumption becomes particularly large.

In addition to this, since the centrifugal weight 73 and the disc spring 71 are integrated, the number of parts can be reduced and the space for disposing the timing gear set 7 can be reduced accordingly.

Further, since the timing gear set 7 does not generate fine movement in the rotation direction which causes gear rattle in the low rotation range,
The gap between the rotors 43 and 45 is prevented from fluctuating and hitting,
The efficiency and durability of the compressor 9 are improved.

Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment is defined in claims 1, 4,
5 has the characteristics of FIG. 5, and FIG. 5 shows a timing gear set 91 of this embodiment. The left and right directions are the left and right directions in each of these figures, and members and the like without reference numerals are not shown.

The timing gear set 91 of this embodiment is
The supercharger 1 of the first embodiment is configured to be replaced with the timing gear set 7 and, like the timing gear set 7, synchronizes the screw rotors 43 and 45 with the driving force of the engine input from the pulley 3. Drive to rotate. Therefore, in the following description, the members having the same functions as those of the first embodiment will be designated by the same reference numerals and will not be described repeatedly.

As shown in FIGS. 5 and 6, the timing gear set 9
Reference numeral 1 includes large-diameter and small-diameter timing gears 65 and 67, and a scissor gear 93 (backlash adjusting gear).

The scissors gear 93 is composed of a boss portion 95, a flexible flange portion 97, and a gear portion 99.
The gear portion 99 is formed on the outer periphery of the flange portion 97,
The number of teeth is the same as that of the timing gear 65. Further, the flange portion 97 has an inclination angle with respect to a plane perpendicular to the rotation axis.

As shown in FIG. 5, the scissors gear 93 is press fitted onto the outer circumference of the rotor shaft 33 of the screw rotor 43. Boss portion 95 of the scissors gear 93 and the timing gear 6
5 and the rotor shaft 33 of the screw rotor 43
Is provided with keyways 101, 103, 105,
The scissors gear 93 and the timing gear 65 are rotationally positioned by a key 107 (positioning member: backlash holding member) that engages with the key grooves 101, 103, 105.

The scissors gear 93 is thus fitted to the rotor shaft 3
A gap 109 is formed between the gear portion 99 of the scissor gear 93 and the timing gear 65 in a state of being fixed to the position 3, as shown in FIGS. 5 and 7.

Further, the scissors gear 93 is positioned with respect to the timing gear 65 by the positioning by the key 107.
As shown in FIG. 7, it is slightly rotationally displaced in the direction of arrow 111. As a result, the backlash 113 between the timing gear 65 and the timing gear 67 is absorbed by the scissors gear 93 and adjusted to a value smaller than a predetermined value, as indicated by an arrow 115.

In addition to this, since the flexible flange portion 97 is inclined with respect to the plane perpendicular to the rotation axis, when the rotation speed of the scissor gear 93 increases together with the timing gear 65, the flange portion 97 and the gear portion 97 99 functions as a centrifugal weight, the gear portion 99 is displaced to the left, and the gap with the timing gear 65 is widened, and a gap 117 wider than the gap 109 during low speed rotation is generated as shown in FIGS. 6 and 8.

As the gap between the gear portion 99 and the timing gear 65 is widened, as shown in FIG.
Further, the tooth lines 119 and 121 of the timing gear 65 are substantially on the same line, and the backlash 123 between the gear portion 99 and the timing gear 67 is also widened.

As described above, when the backlash adjusting function of the scissors gear 93 disappears, the timing gears 65 and 67 are released.
Meshes with a backlash 113 having a predetermined value larger than the adjustment value during low speed rotation.

In this way, the timing gear set 91 is constituted.

As described above, in the timing gear set 91, the backlash of each of the timing gears 65 and 67 is adjusted to an adjustment value smaller than a predetermined value in the low speed rotation range, and when the rotation speed increases, the backlash is larger than that. Return to value backlash.

Therefore, since the backlash is narrowed during the low speed rotation of the engine such as during idling, the gear rattling noises of the timing gears 65 and 67 are prevented and the torque is prevented from coming off even if the torque fluctuates. Therefore, smooth torque transmission can be performed.

Furthermore, since no rattling noise is produced, quietness is maintained even when the engine is running at low speed and has low noise.

When the engine speed increases, the backlash of the timing gears 65 and 67 returns to a predetermined value, and the backlash between the scissors gear 93 and the timing gear 67 spreads, so that the friction between the respective gears is reduced, and compared with the conventional example. As a result, power transmission efficiency and engine fuel efficiency are improved.

Since torque fluctuation is unlikely to occur when the engine is rotating at high speed, gear rattle does not occur even if the backlash of the timing gear set 91 is increased.

Further, by increasing the backlash in this manner at the time of high speed rotation in which the driving force loss due to friction increases, the effect of improving the power transmission efficiency and the fuel consumption becomes particularly large.

In addition to this, by forming the gear portion 99 of the scissors gear 93 on the outer periphery of the flexible flange portion 97 inclined with respect to the plane perpendicular to the rotation axis, as described above, Since the flexible flange portion 97 and the flexible flange portion 97 function as a centrifugal weight, it is not necessary to separately provide a centrifugal weight, the number of parts is reduced, and the arrangement space is small.

Further, since the timing gear set 91 does not have fine movement in the rotation direction which causes gear rattling noise in the low rotation range, fluctuations and hits in the gap between the rotors 43 and 45 are prevented, and the efficiency and durability of the compressor 9 are improved. And improve.

In the gear set of the present invention, for example,
A cam surface may be provided on the backlash adjusting gear, and a centrifugal weight may be applied to the cam surface at the time of high speed rotation to move the backlash adjusting gear in the axial direction to widen the backlash.

As described above, in the gear set of the present invention, the gear may have external teeth or internal teeth.

Further, the fluid machine according to the sixth aspect may be used not only as a compressor or a blower but also as a fluid pressure motor for applying fluid pressure to take out rotation. Further, it is not limited to a screw type fluid machine using a screw rotor, but may be a roots type fluid machine using a cocoon-shaped rotor.

[0095]

As described above, in the gear set according to the first aspect of the present invention, the tooth surface of the backlash adjusting gear is displaced in the rotational direction from the tooth surface of the one gear by the amount corresponding to the adjustment of the backlash so that the one gear is rotated. The backlash between the other gear and the other gear is set to an adjustment value smaller than the initial predetermined value, and this adjustment value is held by the backlash holding member.

When the rotational speed increases, the centrifugal weight moves the backlash adjusting gear in the axial direction, and the backlash adjusting function disappears. Therefore, the backlash of one gear and the other gear is larger than the adjustment value at the time of low speed rotation. Returns to the initial value.

Therefore, even if the torque fluctuates during low-speed rotation, the backlash is small, so gear rattle is prevented, and quietness is maintained during low-speed engine rotation with low noise.

Further, as the number of revolutions increases, the backlash becomes wider and the friction between the gears is reduced, so that the power transmission efficiency and the fuel consumption of the prime mover are improved and the driving force loss is increased as compared with the conventional example. Since the backlash is increased in this way at the time of high speed rotation, the effect of improving power transmission efficiency and fuel efficiency is particularly great. Further, since torque fluctuations are less likely to occur during high speed rotation, gear rattle does not occur even if the backlash between gears is increased.

Further, basically, since the backlash of the one and the other gears is not forcibly reduced, the load on each gear and the bearing supporting each gear is greatly reduced, and the durability is improved.

A gear set according to a second aspect of the present invention uses a friction gear as a backlash adjusting gear, and similarly to the configuration of the first aspect, the gear rattling noise of the gear occurs even when torque fluctuation occurs during low speed rotation. Is prevented, and power transmission efficiency and fuel efficiency are improved when the rotation speed is increased.

In addition to this, the same effect as that of the first aspect is obtained.

The gear set according to claim 3 has the same effect as that of the structure according to claim 2, and since the centrifugal weight and the disc spring are integrated, the number of parts is reduced and
The space for disposing the centrifugal weight and disc spring can be small.

According to a fourth aspect of the invention, a scissors gear is used as a backlash adjusting gear.
Similar to the configuration described above, gear rattling noise between gears is prevented even when torque fluctuations occur during low speed rotation, and power transmission efficiency and fuel efficiency improve as the rotational speed increases.

In addition to this, the same effect as that of the first aspect is obtained.

The gear set according to claim 5 has the same effect as that of the structure according to claim 4, and has a flexible flange member inclined from a plane perpendicular to the rotation axis and a backlash adjusting gear formed on the peripheral portion thereof. And function as centrifugal weights,
It is not necessary to separately provide a centrifugal weight, the number of parts is reduced, and the arrangement space is small.

As described above, the fluid machine according to claim 6 is characterized in that, as described above, the rattling noise is prevented and there is no fine movement in the rotational direction which causes the rattling noise. By using the gear set of as the timing gear set,
The rotor clearance is prevented from fluctuating and hitting, improving efficiency and durability, maintaining quietness even when the engine runs at low speed, and backlash of the timing gear set returns to its normal value in the high speed range. , The power transmission efficiency and the fuel economy of the prime mover are improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part of the first embodiment showing a change in backlash during high-speed rotation.

FIG. 3 is a meshing state diagram of a gear set showing a change in backlash at low speed rotation in the first embodiment.

FIG. 4 is a meshing state diagram of a gear set showing a change in backlash during high-speed rotation in the first embodiment.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts of a second embodiment showing a change in backlash during high speed rotation.

FIG. 7 is a meshing state diagram showing backlash change at low speed rotation in the second embodiment.

FIG. 8 is a meshing state diagram showing a change in backlash during high-speed rotation in the second embodiment.

FIG. 9 is a sectional view of a conventional example.

FIG. 10 is a view showing a backlash absorbing function of the conventional example of FIG.

[Explanation of symbols]

 7, 91 Timing gear set (gear set) 9 Screw type compressor 9 (fluid machine) 13 Compressor casing (casing) 43, 45 Screw rotor (rotor) 65 Timing gear (one gear) 67 Timing gear (other gear) 69 Friction gear (backlash adjusting gear) 71 Disc spring (spring: backlash holding member) 73 Centrifugal weight 87 Intake port (inlet) 89 Discharge port (outlet) 93 Scissors gear (backlash adjusting gear) 97 Flexible flange 99 gear (backlash adjusting gear) 107 key (positioning member: backlash holding member)

Claims (6)

[Claims] 1. A pair of gears that mesh with each other with a predetermined backlash, and a pair of gears that mesh with the other gear in a state in which the tooth flanks of one gear are displaced in the rotational direction by an amount corresponding to the adjustment of the backlash, and the gears of both gears mesh with each other. A backlash adjusting gear that adjusts to a value smaller than the predetermined backlash, and a backlash holding member that holds the backlash adjustment gear and one gear in the rotational direction displacement, and holds the backlash of both gears at the adjustment value. A gear set characterized by comprising a centrifugal weight and moving the backlash adjusting gear in the axial direction by the centrifugal force of the centrifugal weight during high speed rotation so that the backlash between one gear and the other gear is greater than during low speed rotation. . 2. The invention according to claim 1, wherein the backlash adjusting gear has a number of teeth different from that of one gear and is rotatably arranged relative to the one gear.
The backlash holding member is a spring that presses the backlash adjusting gear against one gear and holds the displacement in the rotational direction between the backlash adjusting gear and the one gear due to the frictional force.The centrifugal force of the centrifugal weight pushes this spring. The gear set is characterized in that the backlash adjustment gear can be rotationally displaced with respect to one gear at the time of high-speed rotation, and the backlash is made larger than that at the time of low-speed rotation by reducing. 3. The invention according to claim 2, wherein the spring is
A gear set which is a disc spring that presses a backlash adjusting gear against one gear, and a centrifugal weight is fixed to the disc spring, and the pressing force of the disc spring is reduced by centrifugal force. 4. The invention according to claim 1, wherein the number of teeth of the backlash adjusting gear is the same as the number of teeth of one gear, and the backlash holding member is each tooth of the backlash adjusting gear and one gear. A positioning member that positions these surfaces in the rotational direction with the surfaces displaced in the rotational direction by the amount of backlash adjustment.The centrifugal weight moves the backlash adjustment gear in the axial direction during high-speed rotation, and A gear set characterized by having a greater backlash with the other gear than during low speed rotation. 5. The backlash adjusting gear according to claim 4, wherein the backlash adjusting gear is provided on a peripheral portion of a flexible flange member having an inclination angle with respect to a plane perpendicular to the rotation axis. The adjustment gear and the flexible flange member serve as a centrifugal weight, and the backlash adjustment gear moves in the axial direction at high speed rotation, and the backlash between one gear and the other gear is made larger than at low speed rotation. Gear set to do. 6. A pair of rotors intermeshing with each other, a rotor for rotatably enclosing the rotors, a fluid inlet provided on a meshing start side of each rotor and a fluid outlet provided on a meshing end side of each rotor. And a timing gear set that meshes the rotors in synchronization with each other without contacting each other, and the timing gear set is the gear set according to any one of claims 1 to 5. Fluid machine characterized by.