JP2002349672A - Noise reduction device of gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise reduction device of a gear, capable of surely reducing the meshing noise or the knocking noise due to a collision of tooth face of a gear and moreover of suppressing drive loss to a minimum. SOLUTION: A spline projection part 7 is provided in a pump gear, where a rotation of a crankshaft of an engine is transmitted, a spline recess part 8 is provided in a pump shaft 3 of a fuel injection pump, a vane 8b is formed to move in a vane chamber 8b of the vane recess part 8, followed by relative rotation with the pump gear 4 and the pump shaft 3, and the collision of the tooth face of the pump gear and an idler gear is relaxed, by using the buffer action with oil supplied into both side oil chambers 8c, 8d of a vane 7b and damping action, followed by the movement of the vane 7b in the vane chamber 8b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear noise reduction apparatus for reducing meshing noise and rattling noise due to backlash between gears when transmitting rotation through gears.

[0002]

2. Description of the Related Art As is well known, in a gear structure in which a driven device whose driving load fluctuates is driven by a driving source via a gear train, gear tooth surfaces collide due to backlash between the gears. It is known to cause noise increase. As a measure for suppressing such a phenomenon, a scissor gear can be cited. As is well known, the scissor gear is arranged to overlap with the original gear (Doblin gear), and is urged in the anti-rotational direction by a spring to prevent collision of the tooth surface between the Doblin gear and the mating gear. is there.

However, the application of scissor gears is limited to gears having relatively low transmission torque. In other words, as the transmission torque increases, the torque when the gear rotates in the forward and reverse directions also increases, so that the spring needs to be strengthened. However, as the spring is strengthened, the pressing force of the mating gear against the tooth surface increases, causing a problem of promoting abrasion. As a result, the transmission torque is restricted as described above.

Therefore, as a noise reduction device using a principle different from scissors gear, for example, Japanese Patent Laid-Open No.
No. 89 can be mentioned. This noise reduction device is applied to a fuel injection pump of a diesel engine, and the fuel injection pump is rotatably driven by a crankshaft of the engine via a pump gear fixed to an input shaft thereof and an idler gear. Has become. Since the load of the fuel injection pump fluctuates in synchronism with the pumping of fuel to each cylinder, the load fluctuation causes the pump gear to repeat minute forward and reverse rotations within the range of backlash with the idler gear, causing a collision due to a tooth surface collision. Generates sound.

In the noise reduction device described in the above publication, a number of moving blades corresponding to the number of cylinders are annularly arranged on the back surface of the pump gear, and an inner and outer double oil reservoir forming an annular shape with respect to these moving blades. A single stator is provided in the oil reservoir on the outer peripheral side, which is disposed to face the outer periphery. The blade rotating with the pump gear acts as a kind of centrifugal pump, sucks up the oil in the oil reservoir on the inner peripheral side, discharges it to the oil reservoir on the outer peripheral side, and circulates the oil. Each rotor blade sequentially corresponds to the stator in the oil, and due to the fluid interference generated at this time, a torque variation having a phase opposite to that of the load variation of the fuel injection pump is generated, thereby preventing a tooth surface collision.

[0006]

However, in the gear noise reduction device described in the official gazette, since the rotor blades function as a centrifugal pump as described above, the drive loss of the fuel injection pump is greatly increased. As a result, there is a problem that adverse effects such as deterioration of fuel efficiency of the engine are caused.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gear noise reduction device capable of reliably reducing a collision noise caused by a collision of a gear tooth surface while suppressing a drive loss to a minimum.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a driving gear is meshed with a driven gear engaged with an input shaft of a driven device, and the driving gear and the driven gear are interposed. In the gear structure for transmitting the rotation of the driving source to the driven device, the cylinder chamber provided in one of the input shaft of the driven device and the driven gear, and the input shaft of the driven device and the driven gear A vane member provided on the other side, for partitioning the cylinder chamber into a pair of oil chambers, and moving in the cylinder chamber with relative rotation between the input shaft and the driven gear;
A hydraulic oil supply means for supplying hydraulic oil into the cylinder chamber, and an orifice passage for flowing hydraulic oil between the oil chambers as the vane member moves in the cylinder chamber are provided.

Therefore, the rotation of the driving source is transmitted to the driven device via the driving gear and the driven gear. At this time, since the operating oil is supplied into the cylinder chamber, the operation between the cylinder chamber and the vane member is performed. The rotation is transmitted via oil,
The hydraulic oil itself has a buffering action. Further, when the vane member moves in the cylinder chamber due to the collision of the tooth surfaces of the drive gear and the driven gear, the hydraulic oil flows between the two oil chambers through the orifice passage, and a damping action that appropriately hinders the movement of the vane member. To play. Therefore, the collision of the tooth surfaces when the driving torque of the driven device fluctuates is alleviated by the buffering action of these hydraulic oils and the damping action accompanying the movement of the vane member.

Since the operating oil is merely supplied to the oil chamber in this manner, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-261289, in which the moving blades of a pump gear function as a centrifugal pump, There is no factor that increases the drive loss of the driven device, and the hydraulic oil supplied to the oil chamber only flows through the orifice passage or leaks slightly from the clearance of each part. , The driving loss of the hydraulic oil supply means does not increase.

According to the second aspect of the present invention, both supply positions for supplying the hydraulic oil from the hydraulic oil supply means to both oil chambers in the cylinder chamber, and the oil chamber on the side whose volume is reduced with rotation transmission are provided. Supply position switching means configured to be switchable between a one-side supply position for supplying hydraulic oil from hydraulic oil supply means, and one-side supply of supply position switching means prior to an increase in driving torque of a driven device. And a hydraulic oil control means for switching the supply position switching means to the both-side supply position prior to the reduction of the driving torque of the driven device.

Therefore, prior to the increase in the driving torque of the driven device, the supply position switching means is switched to the one-side supply position, and the hydraulic oil is supplied to the oil chamber on the side whose volume is reduced in accordance with the rotation transmission. , The vane member is moved to one stroke end in the cylinder chamber. Thereafter, when the tooth surfaces collide with an increase in the driving torque, the vane member moves in the cylinder chamber and exerts a damping action by the orifice passage. At this time, the vane member moves the entire stroke movable in the cylinder chamber. Therefore, the collision of the tooth surfaces is sufficiently reduced.

[0013] The present invention is preferably a gear that engages an idler gear with a pump gear fixed to a pump shaft of a fuel injection pump of a diesel engine, and transmits rotation of a crankshaft of the engine to the fuel injection pump via the idler gear and the pump gear. In the structure, a spline recess provided on the pump shaft of the fuel injection pump and having a plurality of vane chambers on the inner periphery, and a plurality of vanes provided on the pump gear on the outer periphery are provided.Each vane is provided in the vane chamber of the spline recess. While being arranged and partitioned into a pair of oil chambers, a spline convex portion for moving the vane in the vane chamber with the relative rotation of the pump shaft and the pump gear, oil supply means for supplying oil into the oil chamber, The orifice passage through which oil flows between the oil chambers and the oil chambers inside the vane chamber A spool configured to be switchable between a two-side supply position for supplying oil from the oil supply means and a one-side supply position for supplying oil from the oil supply means to an oil chamber on the rotation direction side, and a fuel injection pump. Prior to the start of injection of the fuel injection pump, oil control means for switching the spool to the one-side supply position and switching the spool to the both-side supply position prior to the end of injection of the fuel injection pump. It can be embodied as a reduction device.

In the fuel injection pump, when the pump load suddenly increases with the start of the fuel injection, the tooth surfaces of the pump gear and the idler gear collide with each other to generate a meshing noise, and the pump load sharply decreases with the end of the fuel injection. Then, the tooth surfaces of both gears alternately collide within the backlash range, and rattling noise is generated. These meshing noises and rattling noises are reduced by the buffering action of oil in the oil chamber and the movement of the vane. Can be reduced by the damping effect accompanying the above.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a gear noise reduction device applied to a diesel engine fuel injection pump will be described below. FIG. 1 is a partial cross-sectional view showing a gear noise reduction device of the present embodiment, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 showing a relationship between an oil chamber and an oil passage. The fuel injection pump 1 (driven device) is fixed to a cylinder block of an engine (drive source) not shown, and FIG. 1 partially shows a front part of a housing 2 of the fuel injection pump 1. The fuel injection pump 1 is configured as, for example, a known distribution type pump. In the housing 2, a pump shaft 3 (input shaft) that rotationally drives inner cams corresponding to the number of cylinders of the engine is rotatably supported.

A pump gear 4 (driven gear) is disposed at a front position of the housing 2 so that the pump shaft 3 and the axis L coincide with each other.
a is formed. The tooth profile of the pump gear 4 may be configured as a straight gear or a helical gear. The bearing portion 4 a is provided in a bearing hole 2 a formed in the housing 2, and the entire pump gear 4 is rotatably supported via a radial needle bearing 5. A spline projection 7 is integrally formed on the rear end face of the bearing 4a of the pump gear 4, and a spline recess 8 is formed on the front end face of the pump shaft 3 corresponding to the spline projection 7.

As shown in FIG. 2, the spline projections 7
Four vanes 7b (vane members) are protruded from the outer periphery of the cylindrical portion 7a at 90 ° intervals. On the other hand, the spline recess 8 has four vane chambers at 90 ° intervals on the inner periphery of the cylindrical hole 8a. 8b (cylinder chamber) is formed. The cylindrical portion 7a of the spline convex portion 7 has a cylindrical hole 8 of the spline concave portion 8.
a, and each vane 7b of the spline convex portion 7 is disposed in each vane chamber 8b of the spline concave portion 8.

Each vane chamber 8b is circumferentially partitioned by the vane 7b into a pair of oil chambers 8c and 8d. When the spline convex portion and the spline concave portion slightly rotate about the axis L, the vane chamber 8b Moves the vane 7b,
Accordingly, the volumes of the two oil chambers 8c and 8d change in opposite directions. Here, a gap S (orifice passage) between the tip of the vane 7b and the inner wall of the vane chamber 8b is set based on strict tolerance in order to obtain a predetermined orifice effect when oil flows as described later. ing.

A gear case 9 is provided on the front side of the pump gear 4, and the front side of the pump gear 4 is rotatably supported by a radial ball bearing 10 and a thrust ball bearing 11 provided in the gear case 9. The pump gear 4 meshes with an idler gear 12 (drive gear) rotatably supported by a cylinder block. Although not shown, the idler gear 12 meshes with a drive gear fixed to a crankshaft of the engine, and The rotation of the pump gear 4 through the idler gear 12
And the fuel injection is performed in synchronization with the rotation of the engine as described above.

On the other hand, a sleeve hole 13 is formed in the pump gear 4 along the axis L, and a spool 14 (supply position switching means) having a pair of front and rear grooves 14a, 14b on the outer periphery in the sleeve hole 13. Are arranged. The spool 14 is slid in the sleeve hole 13 by the solenoid 15, and is switched to the one-side supply position in FIG. 1 which slides forward when the solenoid 15 is excited, and is switched to the two-side supply position in FIG. 3 which slides backward when the solenoid is demagnetized. Can be

A single oil groove 16 is formed on the outer circumference of the bearing portion 4a of the pump gear 4 over the entire circumference. The oil groove 16 is not shown in the drawing of the engine through a first oil passage 17 formed in the housing 2. It is connected to the discharge side of a lubrication oil pump (hydraulic oil supply means), and oil is always supplied into the oil groove 16. One end of the second oil passage 18 is connected to one side of the oil groove 16, and the other end of the second oil passage 18 is bifurcated forward and backward, and opens into the sleeve hole 13. I have. As shown in FIGS. 1 and 2, one end of a third oil passage 19 is opened in the sleeve hole 13, and the other end of the third oil passage 19 is branched into four, each of which has the spline projection. The portion 7 communicates with the base of each vane 7b on the rotation direction side, that is, the inside of the oil chamber 8c located on the rotation direction side. Further, as shown in FIGS. 3 and 4, one end of a fourth oil passage 20 is opened in the sleeve hole 13, and the other end of the fourth oil passage 20 is branched into four, each having a spline projection. Each of the vanes 7b is in communication with a base portion on the anti-rotation direction side of the respective vanes 7b, that is, an oil chamber 8d located on the anti-rotation direction side.

When the spool 14 is switched to the one-side supply position shown in FIG. 1, the second oil passage 18 communicates with the third oil passage 19 via the groove 14b, while the spool 14 is moved to the position shown in FIG. When the position is switched to the two-sided supply position shown in the figure, the second oil passage 18 is connected to the fourth oil passage 20 through the groove 14a while the communication between the second oil passage 18 and the third oil passage 19 is maintained.
Communicate with

On the other hand, in the passenger compartment, an input / output device (not shown), storage devices (ROM, RAM, etc.) for storing control programs and control maps, and a central processing unit (CP) are provided.
U), an ECU (electronic control unit) 21 (working oil control means) including a timer counter and the like is provided. EC
Various sensors such as an accelerator sensor 22 for detecting an accelerator operation amount and a rotational speed sensor 23 for detecting an engine rotational speed are connected to an input side of the U21, and the solenoid 15 is connected to an output side of the ECU 21. At the same time, various actuators of the fuel injection pump 1 are connected.

The ECU 21 has an accelerator sensor 22
The fuel injection amount and the injection timing of the fuel injection pump 1 are controlled on the basis of information such as the accelerator operation amount detected by the ECU and the engine rotation speed detected by the rotation speed sensor. On the other hand, the ECU 21 controls the switching of the spool 14 by means of the solenoid 15 to appropriately supply oil into the oil chambers 8c and 8d, and makes use of a buffering action and a damping action provided by the oil to connect the pump gear 4 and the idler gear 12 with each other. The collision sound generated by the collision of the tooth surface is reduced. Therefore, the control will be described in detail below.

The switching of the spool 14 is controlled based on the fuel injection timing as shown in the time chart of FIG. First, before fuel injection starts,
For example, at timing a, the solenoid 15 is demagnetized (turned off), and the spool 14 is switched to the both-side supply position shown in FIG. Therefore, the oil in the oil groove 16 is supplied to the second oil passage 18, the groove 14 b of the spool 14, and the third oil passage 19.
, And is supplied into the oil chamber 8d on the opposite rotation direction through the second oil passage 18, the groove 14a of the spool 14, and the fourth oil passage 20. As a result, the vanes 7b of the spline projections 7 are moved to the oil chambers 8 on both sides.
Receiving balanced hydraulic pressures from c and 8d, the vane chamber 8b is located at approximately the neutral stroke.

From this state, when it reaches timing b preceding the start of fuel injection by a predetermined time, the solenoid 15 is excited (turned on), and the spool 14 is switched to the one-side supply position shown in FIG. As a result, the oil chamber 8d on the anti-rotation direction side
The supply of oil to the spline projections 7 is interrupted, and the oil is supplied only to the rotation-side oil chamber 8c (that is, the oil chamber whose volume is reduced along with rotation transmission).
Vane 7b will be received. As a result, as shown in FIG. 2, the vane 7b moves to the stroke end on the opposite rotation direction side, and the rotation of the pump gear 4 is changed to the oil chamber 8 on the rotation direction side.
The oil is transmitted to the pump shaft 3 via the oil in c.

Thereafter, when fuel injection is started at timing c, the load on the fuel injection pump 1 increases rapidly. That is,
Since the cam corresponding to the fuel injection cylinder pushes up the plunger to increase the fuel pressure in the plunger barrel, the rotational resistance of the pump shaft 3 temporarily increases suddenly. At this time, the idler gear 12 transmits the rotation while the tooth surfaces are almost in contact with the pump gear 4, but if the tooth surfaces of the gears 4 and 12 are slightly separated at the moment when the pump load suddenly increases. In this case, the tooth surfaces collide with each other and cause a collision noise (hereinafter referred to as a meshing noise).

Here, as described above, in the present embodiment, since the rotation is transmitted through the oil in the oil chamber 8c on the rotation direction side, the oil itself has a buffering action. In addition, the vane 7b at the time of the tooth surface collision causes the oil in the oil chamber 8c to flow to the oil chamber 8d while the vane 7b
At this time, the orifice effect of the oil flowing between the tip of the vane 7b and the inner wall of the vane chamber 8b exerts an attenuating action to appropriately hinder the movement of the vane 7b. Then, due to the buffering action by the oil and the damping action caused by the movement of the vane 7b, the collision of the tooth surfaces when the pump load increases sharply is reduced.

On the other hand, at a timing d preceding the end of the fuel injection by a predetermined time, the solenoid 15 is demagnetized and the spool 14 is switched to the both-side supply position shown in FIG. As a result, the supply of oil to the oil chamber 8d on the anti-rotational direction side is restarted, and the vane 7b is moved to the oil chambers 8c and 8d on both sides.
Receives balanced hydraulic pressure from Thereafter, when the fuel injection is terminated at timing e, the load on the fuel injection pump 1 sharply decreases. At this time, not only does the rotational resistance of the pump shaft 3 suddenly decrease at the same time as the spill, but also immediately after that, the plunger gets over the cam mountain and is pushed down by receiving the urging force of the plunger spring. The force in the direction of acceleration acts on it. Therefore, the tooth surfaces of the pump gear 4 and the idler gear 1 alternately collide within a backlash range, which causes a collision noise (hereinafter referred to as a rattling noise).

At this time, the same operation as that at the time of the sudden increase of the pump load is performed on both sides of the vane 7b. That is, since the oil chambers 8c and 8d are formed on both sides of the vane 7b, the oil in each oil chamber exerts a buffering action in the rotation direction and the anti-rotation direction, and the oil between the oil chambers 8c and 8d. Vane 7 while alternately circulating
b is appropriately prevented from moving in both directions, and exhibits a damping action in the rotational direction and the anti-rotation direction. Therefore, the collision of the tooth surface when the pump load suddenly decreases is reduced.

As described above, in the gear noise reduction device of the present embodiment, the vane 7b on the pump gear 4 side is moved in the vane chamber 8b provided on the pump shaft 3 with the relative rotation of the pump gear 4 and the pump shaft 3. When the fuel injection is started, the oil is supplied to the oil chamber 8c in advance, and when the fuel injection is completed, the oil is supplied to the oil chambers 8c and 8d in advance. Therefore, if the pump load increases sharply with the start of fuel injection, an oil buffering action and a damping action due to the movement of the vane 7b are exerted, so that the collision of the tooth surfaces in the gear rotation direction is reduced, and the fuel injection is started. When the pump load suddenly decreases with the end, the oil buffering action and the damping action accompanying the movement of the vane 7b are similarly exerted, and the collision of the tooth surfaces in the gear rotation direction and the counter rotation direction is reduced, and as a result, meshing It is possible to reliably reduce the noise and rattling noise, and to achieve a reduction in noise of the entire engine.

FIG. 6 shows the measurement results of the noise levels of the engine provided with the gear noise reduction device of the present embodiment and the normal engine. In comparison, it can be seen that the noise level is reduced in almost the entire frequency band, and a large reduction width is obtained particularly in the high frequency band. Moreover, in general, the occupant of the vehicle tends to feel harsh noise including a large amount of high-frequency components, so that the impression of noise reduction given to the occupant is more preferable than the measured values in the figure.

Also, as is apparent from the above configuration, the oil chamber 8
Since oil is only supplied to the inside of c and 8d, for example, the driving loss of the fuel injection pump is reduced as in the technique described in JP-A-8-261289 in which the moving blade of the pump gear functions as a centrifugal pump. There is no increase factor. Further, the oil supplied to the oil chambers 8c and 8d only flows between the two oil chambers or leaks slightly from the clearance of each part. There is no need to take measures such as increasing the discharge amount of the pump, and the drive loss on the engine side does not increase. Therefore, the above-described noise reduction effect can be obtained while preventing adverse effects such as deterioration of fuel efficiency of the engine.

In addition, the oil passages to the oil chambers 8c and 8d are switched by the spool 14 in accordance with the start and end of the fuel injection as described above. It is moved to the stroke end on the anti-rotation direction side. As a result, the vane 7b exerts the damping action with the entire stroke movable in the vane chamber 8b, and as a result, the collision of the tooth surfaces accompanying the start of fuel injection is sufficiently mitigated, and the meshing sound is reliably reduced. There is also an advantage that it can be suppressed.

The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, the gear noise reduction device applied to the fuel injection pump 1 of the diesel engine has been embodied. If it is possible, it is not limited to this. Therefore, for example, in an engine in which rotation of a crankshaft is transmitted to a camshaft via a gear train, the above-described vane chamber 8 is provided between the front end of the camshaft and the gear.
b, vanes 7b, oil passages 17 to 20, etc. may be provided. As in the case of the fuel injection pump 1, a load fluctuation occurs on the camshaft due to the reaction force of the valve spring, so that the gear on the camshaft side is positive with the gear on the other side within the backlash range. Although the tooth surface is collided by the reverse rotation, the same effect as that of the embodiment can be obtained with the above-described configuration, and the collision of the tooth surface can be reduced to suppress the meshing sound and the rattling sound.

In the above embodiment, the oil passage is switched by the spool 14 in synchronization with the fuel injection. However, for example, the construction of the spool 14 and the solenoid 15 for switching the oil passage is omitted. The oil from the oil pump may be constantly supplied to the corresponding oil chambers 8c and 8d via the third oil passage 19 and the fourth oil passage 20. In this case, the vane 7b is located almost at the neutral position of the stroke in the vane chamber 8b at the start time as well as at the end of the fuel injection, so that the stroke of the vane 7b is reduced by half and the damping action is weakened. Combined with the oil buffering effect, the noise can be sufficiently reduced as compared with a normal engine. And the spool 14 and the solenoid 1
By omitting 5, etc., the configuration of the noise reduction device is greatly simplified, and as a result, a sufficient noise reduction effect can be obtained with a minimum cost.

Further, in the above-described embodiment, the gap S between the tip of the vane 7b and the inner wall of the vane chamber 8b is set with strict tolerance, and the oil is circulated in this location to obtain the orifice effect. As shown by a solid line, the oil chambers 8c and 8d on both sides of the vane 7b are connected by a communication passage 31 having a predetermined cross-sectional area, and oil is circulated through the communication passage 31 to obtain an orifice effect. As shown by the broken line, a communication passage 32 having a predetermined cross-sectional area may be provided through the vane 7b, and oil may be circulated through the communication passage 32 to obtain an orifice effect.

On the other hand, in the above embodiment, the spline projection 7 is formed on the pump gear 4 side, and the spline recess 8 is formed on the pump shaft 3 side. However, the relationship between the two is reversed, and the spline recess 8 is formed on the pump gear 4 side. May be formed, and the spline projection 7 may be formed on the pump shaft 3 side. In the above embodiment, the vane 7b and the vane chamber 8b are provided at four positions around the axis L. However, the vane 7b moves in the vane chamber 8b with the relative rotation between the pump shaft 3 and the pump gear 4. The configuration and the number are not limited as long as the configuration is performed. Therefore, for example, the vane 7b and the vane chamber 8b may be provided at two places at 180 ° intervals around the axis L.

[0039]

As described above, according to the gear noise reduction device of the present invention, the drive loss is minimized,
The meshing noise and the rattling noise due to the collision of the gear tooth surfaces can be reliably reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a gear noise reduction device according to an embodiment when a spool is at a one-side supply position.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial cross-sectional view showing when a spool is at a both-side supply position.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a time chart showing fuel injection timing and spool switching timing.

FIG. 6 is an explanatory diagram showing measurement results of noise levels of an engine provided with the gear noise reduction device of the present embodiment and a normal engine.

FIG. 7 is a partial sectional view showing another example in which the form of the orifice passage is changed.

[Explanation of symbols]

 Reference Signs List 1 fuel injection pump (driven device) 3 pump shaft (input shaft) 4 pump gear (driven gear) 7b vane (vane member) 8b vane chamber (cylinder chamber) 8c, 8d oil chamber 12 idler gear (drive gear) 14 spool (supply) Position switching means) 21 ECU (hydraulic oil control means) S gap (orifice passage)

Claims (2)

[Claims] 1. A gear structure for meshing a driven gear with a driven gear engaged with an input shaft of a driven device and transmitting the rotation of a driving source to the driven device via the driving gear and the driven gear. A cylinder chamber provided on one of the input shaft of the driven device and the driven gear; and a pair of oil chambers provided on the other of the input shaft of the driven device and the driven gear. A vane member that moves in the cylinder chamber along with the relative rotation of the input shaft and the driven gear, a hydraulic oil supply unit that supplies hydraulic oil into the cylinder chamber, and the vane in the cylinder chamber. As the members move,
A gear noise reduction device, comprising: an orifice passage through which hydraulic oil flows between the two oil chambers. 2. A supply position on both sides for supplying the hydraulic oil from the hydraulic oil supply means to both oil chambers in the cylinder chamber, and a hydraulic oil supply means from the hydraulic oil supply means to the oil chamber on the side whose volume is reduced with rotation transmission. Supply position switching means configured to be switchable between one-side supply position for supplying the hydraulic oil, and switching the supply position switching means to one-side supply position prior to an increase in drive torque of the driven device. 2. The gear noise reduction according to claim 1, further comprising: hydraulic oil control means for switching the supply position switching means to a supply position on both sides prior to reduction of the driving torque of the driven device. apparatus.