JP3179940B2 - Engine accessory drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accessory driving device for driving various accessories such as a balancer shaft of an engine and a fuel injection pump by a crankshaft.

[0002]

2. Description of the Related Art Conventionally, when a balancer shaft of an engine is driven by a crank shaft, for example,
As disclosed in JP-A-33316, internal teeth are formed on a cylinder block side around an engine crankshaft, and a balancer shaft meshing with the internal teeth is rotatably supported on a balance weight of the crankshaft. Is driven by a crankshaft via an internal gear.

[0003]

By the way, when the number of balancer shafts is one as in the above-mentioned conventional example, primary vibration of the engine can be reduced, but secondary vibration cannot be reduced. In order to reduce the secondary vibration of the engine, two balancer shafts are provided, each of which is connected to the crankshaft 2.
It is necessary to rotate them in opposite directions at twice the rotation speed.

In this case, the two balancer shafts are driven to rotate in opposite directions at twice the speed of the crankshaft, so that one balancer shaft rotating in the same direction as the crankshaft has one reversing gear and one reverse gear. The other balancer shaft rotating in the direction requires two reversing gears, respectively, so that the gear train becomes complicated, the number of parts increases, and the layout thereof becomes large.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to improve the structure of a gear train when driving an auxiliary machine such as a balancer shaft as described above. It is intended to reduce the weight and size of the device, reduce the number of parts, and the like.

[0006]

In order to achieve the above object, the present invention focuses on the internal gear as in the above-mentioned conventional example, and uses the internal gear to drive the auxiliary machine.

More specifically, according to the first aspect of the present invention, a crank gear attached to a crankshaft of an engine, an external gear having external teeth meshing with the crank gear, and a first gear meshing with the external gear are provided. An accessory driving device for an engine is provided that includes an accessory driving gear that is drivingly connected to the accessory and that transmits the driving force of the crankshaft to the first accessory via a circumscribed gear.

First, internal teeth are formed on the inner surface of the rim of the circumscribed gear. An internal gear meshing with the internal teeth and drivingly connected to the second auxiliary machine is provided.

In the second aspect of the present invention, the second auxiliary device is a balancer shaft that rotates in a direction opposite to a crankshaft.

According to a third aspect of the present invention, in the auxiliary drive device for an engine on the same premise as the first aspect of the invention, an intermediate idler in which the external gear forms a reduction gear having more teeth than the external teeth of the crank gear. Then, internal teeth are formed on the inner surface of the rim portion of the circumscribed gear.

An internal gear meshing with the internal teeth of the external gear and drivingly connected to the second auxiliary machine is provided.

Further, the number of teeth of the internal gear is made smaller than that of the external gear, and the internal gear is accommodated between the shaft portion and the rim of the external gear.

According to a fourth aspect of the present invention, in the accessory driving device for an engine according to the third aspect, the number of external teeth of the circumscribed gear is the same as that of the accessory driving gear, and a friction gear is provided in parallel with the accessory driving gear. I do.

According to a fifth aspect of the present invention, there is provided a driven gear having an axis on a plane passing through the axes of the external gear and the internal gear and meshing with external teeth of the external gear.

According to a sixth aspect of the present invention, in the auxiliary device driving apparatus for an engine according to the third or fourth aspect, the driving device is connected to the internal gear and rotates at a double speed in a direction opposite to the rotation direction of the crankshaft. One balancer shaft and a second balancer shaft that is drivingly connected to the crank gear via an intermediate gear and that rotates at twice the speed in the same direction as the rotation direction of the crank shaft are provided.

In the seventh aspect of the present invention, a plurality of auxiliary devices are drivingly connected to the driven gear, and the plurality of auxiliary devices are coaxially arranged on both sides of the driven gear.

[0017]

According to the above construction, the rotation of the crank gear attached to the crankshaft of the engine is transmitted to the accessory driving gear via the external gear, and the first accessory is driven by the engine. You. The circumscribed gear has internal teeth formed on the inner surface of the rim portion, and the internal gear is meshed with the internal gear that is drivingly connected to the second auxiliary device. The internal gear meshing with the internal teeth is driven to rotate in the direction opposite to the crankshaft, and the second auxiliary machine connected to the internal gear is driven by the crankshaft. In this way, the circumscribed gear for originally driving the first auxiliary machine is used, and the second auxiliary machine is driven via the internal gear by the internal teeth inside the rim portion. Gear train for rotating in the direction
The weight can be reduced and the layout can be made compact.

According to the second aspect of the present invention, since the second auxiliary device is a balancer shaft rotating in the opposite direction to the crankshaft, when the vibration of the engine is reduced by the balancer shaft rotating in the opposite direction to the crankshaft, The balancer shaft can be driven by a compact and simple layout gear train.

According to the third aspect of the invention, the same operation and effect as those of the first aspect of the invention can be obtained. In addition, since the circumscribed gear is an intermediate idler which constitutes a reduction gear, the first idler is provided with respect to the rotation of the crankshaft. The accessory is driven at a reduced speed. on the other hand,
Since the number of teeth of the internal gear that meshes with the internal teeth of the external gear is smaller than the number of internal teeth of the external gear, the second auxiliary device that is drivingly connected to the internal gear is driven at an increased speed.

The internal gear is accommodated between the shaft portion and the rim portion of the external gear having a diameter larger than that of the crank gear by utilizing the structure for decelerating drive of the first auxiliary machine. A structure for simultaneously performing the deceleration drive of one accessory and the speedup drive of the second accessory can be achieved with a compact layout.

Further, when the first auxiliary device is decelerated, the rotation of the external gear is not reduced when the rotation of the external gear is transmitted to the auxiliary device driving gear. Since the rotation is transmitted to the driving gear, the rotation is transmitted at substantially the same speed from the external gear to the accessory driving gear, and the number of external teeth of both gears may be substantially the same as each other, so that the meshing ratio of both gears can be improved. .

According to the fourth aspect of the present invention, since the number of external teeth of the external gear is the same as that of the auxiliary drive gear, the meshing ratio of both gears is further improved and the external gear is arranged in parallel with the auxiliary drive gear. The performance of the friction gear can be improved.

According to the fifth aspect of the present invention, the axis of the driven gear meshing with the external teeth of the external gear is disposed on a plane passing through the axes of the external and internal gears. The internal teeth mesh with the driven gear in the radially outward direction of the circumscribed gear, and the driven gear meshes with the external teeth of the circumscribed gear in the radially inward direction, corresponding to the pressed state. Therefore, noise can be reduced.

According to the sixth aspect of the present invention, the first balancer shaft drivingly connected to the internal gear meshing with the internal teeth of the external gear rotates at twice the speed in the direction opposite to the rotation direction of the crankshaft. On the other hand, the second balancer shaft drivingly connected to the crank gear via the intermediate gear rotates at twice the speed in the same direction as the crank shaft. That is, since the first and second balancer shafts rotate in opposite directions at twice the speed of the crankshaft, secondary rotation of the engine can be reduced by the rotation of these balancer shafts, thereby simplifying the gear train. And compactness can be achieved.

According to the seventh aspect of the present invention, since the plurality of auxiliary devices which are drivingly connected to the driven gear are arranged coaxially with each other on both sides of the driven gear, the plurality of auxiliary devices which are drivingly connected to the driven gear are respectively provided. The machine can be arranged compactly.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, reference numeral 1 denotes a cylinder block of a vehicle diesel engine according to an embodiment of the present invention; 2, a cylinder head mounted on an upper surface of the cylinder block 1; A shaft 3 and a first balancer shaft 4 (a second auxiliary machine) disposed parallel to the crankshaft 3 on the left side of the crankshaft 3
And a second balancer shaft 5 as an auxiliary machine similarly arranged on the right side of the crankshaft 3 are rotatably supported. A fuel injection pump 6 (see FIG. 3) as a first auxiliary device for injecting fuel from a fuel injection nozzle (not shown) into a combustion chamber in each cylinder is provided on the left side of the cylinder block 1.
The drive pulley 8 is attached to the pump shaft 7 of the fuel injection pump 6. A rotary shaft 12 parallel to the crankshaft 3 is disposed and supported on the side wall of the cylinder block 1 below the fuel injection pump 6.
As shown in FIG. 2, a power steering hydraulic pump 13 for generating a hydraulic pressure used in a vehicle power steering device (not shown) is connected to a vacuum pump 14 for generating a negative pressure. , 14 constitute an auxiliary machine.

On the other hand, the crankshaft 3
A driven pulley 10 is attached to an end of the cam shaft 9, and a timing belt 11 is provided between the driven pulley 10 and the driving pulley 8 of the fuel injection pump 6. When the fuel injection pump 6 is driven by the crankshaft 3 via a gear train described later, the rotation of the pump shaft 7 of the fuel injection pump 6 is controlled by the two pulleys 8 and 10 and the timing belt 11.
To the camshaft 9 to rotate the camshaft 9.

Referring to FIG. 1, a gear train for driving each of the above-mentioned auxiliary machines by the crankshaft 3 will be described. A crank gear 15 having external teeth 15a on its outer periphery is integrally mounted on the crankshaft 3. On the other hand, on the pump shaft 7 of the fuel injection pump 6, a pump gear 16 as an accessory driving gear having a larger diameter than the crank gear 15 is integrally mounted on the base side of the driving pulley 8.
External teeth 16a are formed on the outer periphery of 6. A first intermediate shaft 17 parallel to the crankshaft 3 protrudes from a wall of the cylinder block 1 between the crankshaft 3 and the fuel injection pump 6. The first intermediate shaft 17 has the same shape as the pump gear 16. A first intermediate idler 18 as a circumscribed gear having a diameter (larger than the crank gear 15) is rotatably supported.
The first intermediate idler 18 has a rim 18a, and the first balancer shaft 4 is located closer to the center than the rim 18a. External teeth 19 having the same number of teeth as the pump gear 16 and twice as many as the number of crank gears 15 are formed on the outer periphery of the rim portion 18a. The external teeth 19 are the respective external teeth 15a, 15a of the crank gear 15 and the pump gear 16. 16a, and the rotation of the crankshaft 3 is controlled by the first intermediate idler 18a.
After the speed is reduced by half, the transmission is transmitted from the first intermediate idler 18 to the pump gear 16 at a constant speed, and the fuel injection pump 6 is driven by the crankshaft 3.

The rim 18a of the first intermediate idler 18
Internal teeth 20 are formed on the inner periphery. The external teeth 21a of the first balancer gear 21 as an internal gear rotatably attached to the first balancer shaft 4 are meshed with the internal teeth 20. The number of the external teeth 21a of the first balancer gear 21 is the number of teeth. 1 The number of teeth of the intermediate idler 18 is smaller than that of the internal teeth 20,
/ 4. Further, as shown in FIG.
The balancer gear 21 has an outer diameter of the first intermediate idler 18.
The diameter of the rim 18a and the boss 18 of the idler 18 is smaller than the dimension between the rim 18a and the boss 18b (shaft).
b.

On the other hand, a second intermediate shaft 23 parallel to the crankshaft 3 is supported on the wall of the cylinder block 1 between the crankshaft 3 and the second balancer shaft 5. It is drivingly connected to an oil pump for sending engine oil pressure. A second intermediate idler 24 (intermediate gear) having substantially the same diameter as the crank gear 15 is rotatably attached to the second intermediate shaft 23. The outer periphery of the second intermediate idler 24 meshes with the crank gear 15 and External teeth 24a having the same number of teeth as the external teeth 15a are formed. Further, a second balancer gear 25 is attached to the second balancer shaft 5 so as to rotate integrally therewith, and its external teeth 25a are connected to a second intermediate idler 24.
And the number of teeth of the external teeth 25a is half that of the external teeth 24a of the second intermediate idler 24. With this structure, the crankshaft 3 drives the second balancer shaft 5 to rotate. I have to. Therefore, the first balancer shaft 4 is rotated in the direction opposite to the rotation direction of the crankshaft 3 and the second balancer shaft 5
Are rotated at twice the rotational speed in the same direction as the crankshaft 3.

In addition, on the plane P passing through the axes of the first intermediate idler 18 and the first balancer gear 21 outside the rim portion 18a of the first intermediate idler 18, the drive coupling is connected to the power steering hydraulic pump 13 and the vacuum pump 14. The rotating shaft 12 is arranged. This rotating shaft 12
, A driven gear 26 having external teeth 26a is rotatably attached thereto. The external teeth 26a of the driven gear 26 mesh with the external teeth 19 of the first intermediate idler 18 at the position on the plane P. .

As shown in FIG. 2, the vacuum pump 14 is connected to the rotary shaft 12 on the front side of the driven gear 26, and the hydraulic pump 13 is connected to the rotary shaft 12 on the rear side. That is, these two pumps 13 and 14 are coaxially arranged on the rotating shafts 12 on both front and rear sides of the driven gear 26, respectively.

Further, as shown in FIG. 3, a friction gear 28 having a greater number of teeth is arranged in parallel with the pump gear 16 on the pump shaft 7 of the fuel injection pump 6. That is, a pump gear 16 is mounted on the pump shaft 7 of the fuel injection pump 6 at the boss portion 16b, and a ring-shaped friction having a tooth portion 28a on an outer peripheral portion is provided on a front surface (a tip side surface of the pump shaft 7) of the pump gear 16. Gear 28
Are arranged so as to be relatively rotatable. A disc spring 29 is externally fitted to the boss 16b of the pump gear 16, and the disc spring 2
9 is in contact with the front surface of the friction gear 28. On the outer periphery of the boss portion 16 b of the pump gear 16, a bottomed annular pressing boss 30 serving as a spring press for pressing the friction gear 28 against the pump gear 16 by pressing the inner peripheral edge of the disc spring 29 toward the base side is disposed. I have. A screw portion 7a is formed on the outer periphery of the distal end portion of the pump shaft 7, and a mounting nut 31 for fastening and fixing the pressing boss 30 to the pump shaft 7 or the pump gear 16 is screwed to the screw portion 7a. The drive pulley 8 is integrally fixed to the outer periphery of the pressing boss 30.

In FIG. 3, reference numeral 32 denotes a gear case cover.
The gear case cover 32 has a through-hole 32 a for allowing the pump shaft 7, the boss 16 b of the pump gear 16, and the pressing boss 30 to penetrate outside the cover 32. 33 denotes a through hole 32a of the gear case cover 32 and the pressing boss 30.
And an oil seal disposed between the two.

Therefore, in the above embodiment, the crank gear 15 attached to the crankshaft 3 of the engine is used.
Is transmitted to the pump gear 16 on the pump shaft 7 via the first intermediate idler 18. Since the first intermediate idler 18 constitutes a reduction gear, the fuel injection pump 6 is rotationally driven at a speed reduced to half the rotation of the crankshaft 3 by the engine. By this drive, fuel is pumped from the fuel injection pump 6 to the fuel injection nozzle of each cylinder of the engine, and is injected into the combustion chamber from the nozzle. A drive pulley 8 is attached to a pump shaft 7 of the fuel injection pump 6.
The driving pulley 8 is connected to the timing belt 11.
The camshaft 9 is driven and connected to the camshaft 9 via the driven pulley 10, so that the rotation of the crankshaft 3 causes the camshaft 9 to be rotationally driven synchronously.

The first intermediate idler 18 has internal teeth 20 formed on the inner surface of a rim portion 18a of the first intermediate idler 18, and a first balancer gear 21 drivingly connected to the first balancer shaft 4 is formed on the internal teeth 20.
The first balancer gear 21 meshing with the internal teeth 20 is rotationally driven with the driving of the first intermediate idler 18 by the crankshaft 3 because the external teeth 21a of the first gear 21 mesh. Since the number of the external teeth 21a of the first balancer gear 21 is smaller than the number of the internal teeth 20 of the first intermediate idler 18, the speed of the first balancer shaft 4 drivingly connected to the first balancer gear 21 is increased, and the crankshaft 3 Is driven at twice the speed in the opposite direction. On the other hand, the rotation of the crankshaft 3 is controlled by the second intermediate idler 24.
The second balancer gear 25 is meshed with the second intermediate idler 24, and the second balancer gear 25 is connected to the second balancer shaft 5, so that the second balancer shaft 5 rotates with the rotation of the crankshaft 3. Are rotationally driven in the same direction as the crankshaft 3 at twice the speed. That is, since the first and second balancer shafts 4 and 5 are rotationally driven in directions opposite to each other at twice the rotational speed of the crankshaft 3, secondary vibration of the engine can be reduced. The rotation of the second intermediate idler 24 drives the oil pump.

In this case, internal teeth 20 are formed on the inner surface of the rim 18a of the first intermediate idler 18, and the internal teeth 20 are formed.
Since the external teeth 21a of the first balancer gear 21 drivingly connected to the first balancer shaft 4 mesh with the first balancer shaft 4, the first balancer shaft 4 is rotationally driven at twice the speed in the opposite direction to the crankshaft 3. The gear train is simplified, and its weight and layout can be reduced.

The fuel injection pump 6 is driven at a reduced speed with respect to the rotation of the crankshaft 3. The first intermediate idler 18 having a diameter larger than that of the crank gear 15 is utilized by utilizing the speed reduction structure of the fuel injection pump 6. Boss 18b and rim 18a
And the first balancer gear 21 is accommodated between
A structure for simultaneously performing the deceleration drive of the fuel injection pump 6 and the speed-up drive of the first balancer shaft 4 can be achieved with a compact layout.

When the fuel injection pump 6 is driven at a reduced speed, the rotation of the crankshaft 3 is temporarily reduced by the first intermediate idler 18 instead of being reduced when the rotation of the first intermediate idler 18 is transmitted to the pump gear 16. Since the power is transmitted to the pump gear 16 after deceleration, the rotation between the first intermediate idler 18 and the pump gear 16 may be transmitted at a constant speed.
Have the same number of external teeth 19 and 16a,
8 and 16 are improved, and the pump gear 16
The performance of the friction gears 28 arranged side by side is also improved.

On the other hand, the external teeth 1 of the first intermediate idler 18
9 is meshed with the driven gear 26 on the rotating shaft 12, the rotation of the first intermediate idler 18 causes the driven gear 2 to rotate.
The rotary shaft 6 and the rotary shaft 12 are driven to rotate in the same direction as the crankshaft 3, and the hydraulic pump 13 and the vacuum pump 14 for power steering connected to the rotary shaft 12 are driven.

At this time, since the axis of the driven gear 26 is arranged on the plane P passing through the respective axes of the first intermediate idler 18 and the first balancer gear 21, the first balancer gear 21 is Of the first intermediate idler 18 in the radial direction, and the driven gear 26 meshes with the external teeth 19 of the first intermediate idler 18 in the radially inward direction.
At the meshing portions 21 and 26, the driving reaction force balances, and noise reduction at the time of gear meshing can be achieved.

The power steering hydraulic pump 13 and the vacuum pump 14 are respectively driven gears 26.
Are arranged coaxially with each other on both sides of the two pumps 13 and 14, which are drivingly connected to the driven gear 26.
Can be arranged compactly.

In the above embodiment, the first auxiliary device is the fuel injection pump 6 and the second auxiliary device is the first balancer shaft 4, but other auxiliary devices may be driven. Also,
The auxiliary equipment that is drivingly connected to the driven gear 26 is a hydraulic pump 1
A pump other than the pump 3 and the vacuum pump 14 may be employed.

[0044]

As described above, according to the first aspect of the present invention, a crank gear attached to a crankshaft of an engine, an external gear having external teeth meshing with the crank gear, and an external gear meshing with the external gear And an auxiliary device driving gear that is drivingly connected to the first auxiliary device. The auxiliary device driving device for the engine transmits the driving force of the crankshaft to the first auxiliary device via an external gear. An internal gear is formed on an inner surface of a rim portion of the gear, and an internal gear meshing with the internal teeth and drivingly connected to the second auxiliary device is provided. , The second auxiliary machine can be driven via the internal gear by the internal teeth inside the rim part, and the gear train for rotating each auxiliary machine with the crankshaft is simplified, lightened, and the layout is compact. To reduce the number of parts Kill.

According to the second aspect of the invention, the second auxiliary device, which is drivingly connected to the internal gear, is a balancer shaft that rotates in the direction opposite to the crankshaft, so that the vibration of the engine is reduced in the direction opposite to the crankshaft. When reducing by rotating balancer shaft,
The gear train for driving the balancer shaft can be simplified, lightened, and the layout can be made compact.

According to the third aspect of the present invention, the external gear is an intermediate idler that constitutes a reduction gear having more teeth than the external teeth of the crank gear, and the external gear of the internal gear has the external teeth. , The internal gear is accommodated between the shaft portion and the rim portion of the external gear, so that the first auxiliary device is decelerated with respect to the rotation of the crankshaft, while the internal gear is rotated. The second auxiliary device that is drivingly connected to the gear can be driven at an increased speed,
Since the structure for simultaneously performing the deceleration and the speed-up driving of the auxiliary equipment can be achieved with a compact layout, the rotation of the crankshaft is once reduced by the external gear, and then transmitted to the auxiliary equipment drive gear. In addition, the meshing ratio between the auxiliary drive gears can be improved.

According to the fourth aspect of the present invention, the number of external teeth of the external gear is the same as that of the auxiliary drive gear, and the friction gear is arranged in parallel with the auxiliary drive gear. Can further be improved, and accordingly, the performance of the friction gear provided in parallel with the accessory driving gear can be improved.

According to the fifth aspect of the present invention, the driven gear having an axis on a plane passing through the axes of the external gear and the internal gear and meshing with the external teeth of the external gear is provided. In addition, the driven gear can be opposed in the radial direction via the rim portion of the circumscribed gear, and the noise of the gear meshing noise can be reduced by the balance of the driving reaction force at the meshing portion of both gears.

According to the invention of claim 6, the crankshaft 2
First and second balancer shafts rotating in opposite directions at double speed are provided, and the first balancer shaft is drivingly connected to an internal gear, while the second balancer shaft is driven by a crank gear via an intermediate gear. Due to the connection configuration, the secondary vibration of the engine can be reduced by the first and second balancer shafts with a compact and simple gear train.

According to the seventh aspect of the present invention, a plurality of auxiliary machines are connected to the driven gear by driving, and these auxiliary machines are coaxially arranged on both sides of the driven gear. The layout of a plurality of auxiliary devices that are drivingly connected to the gears can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a gear train of an accessory driving device according to an embodiment of the present invention.

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

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a front view of the engine showing a position of a gear train.

[Explanation of symbols]

 3 Crankshaft 4 First Balancer Shaft (Second Auxiliary Machine) 5 First Balancer Shaft 6 Fuel Injection Pump (First Auxiliary Machine) 13 Hydraulic Pump (Auxiliary Machine) 14 Vacuum Pump (Auxiliary Machine) 15 Crank Gear 16 Pump Gear (Auxiliary Machine) Machine drive gear) 17 first intermediate shaft 18 first intermediate idler (external gear) 18a rim 18b boss 19 external teeth 20 internal teeth 21 first balancer gear (internal gear) 24 second intermediate idler (intermediate gear) 26 Drive gear 28 Friction gear P Plane passing through the axis

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Keiji Araki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 67/04 F02B 77/00 F16F 15/26

Claims (7)

(57) [Claims] 1. A crank gear mounted on a crankshaft of an engine, an external gear having external teeth meshing with the crank gear, and an auxiliary drive meshing with the external gear and drivingly connected to a first auxiliary machine. A gear, wherein the driving force of the crankshaft is transmitted to the first auxiliary machine via the circumscribing gear, wherein the internal gear has inner teeth formed on the inner surface of a rim portion of the circumscribing gear; An auxiliary gear driving device for an engine, comprising: an internal gear meshed with internal teeth of an external gear and drivingly connected to a second auxiliary machine. 2. The accessory driving device for an engine according to claim 1, wherein the second accessory is a balancer shaft that rotates in a direction opposite to the crankshaft. 3. A crank gear mounted on a crankshaft of an engine, an external gear having external teeth meshing with the crank gear, and an auxiliary drive meshing with the external gear and drivingly connected to a first auxiliary machine. And a gear, wherein the driving force of the crankshaft is transmitted to the first auxiliary machine through the circumscribing gear, wherein the circumscribing gear has more teeth than the outer teeth of the crank gear. An intermediate idler constituting a reduction gear, an internal gear formed on an inner surface of a rim portion of the external gear, and an internal gear meshing with the internal tooth of the external gear and being drivingly connected to a second auxiliary machine; An auxiliary drive device for an engine, wherein the number of gear teeth is smaller than the number of internal teeth of an external gear, and the internal gear is housed between a shaft portion and a rim portion of the external gear. 4. The accessory driving device for an engine according to claim 3, wherein the number of external teeth of the external gear is the same as that of the accessory driving gear, and a friction gear is arranged in parallel with the accessory driving gear. Auxiliary drive of the engine. 5. The driven device for an auxiliary machine according to claim 1, wherein said driven device has an axis on a plane passing through the axes of said external gear and said internal gear and meshes with external teeth of said external gear. An auxiliary drive device for an engine, wherein a gear is provided. 6. The auxiliary drive device for an engine according to claim 3, wherein the first balancer shaft is drivingly connected to the internal gear, and rotates at twice the speed in a direction opposite to the rotation direction of the crankshaft. A second gear that is drivingly connected to the crank gear via an intermediate gear and that rotates at twice the speed in the same direction as the rotation direction of the crank shaft;
An auxiliary drive device for an engine, comprising: a balancer shaft. 7. The accessory driving apparatus for an engine according to claim 5, wherein a plurality of accessories are driven and connected to the driven gear, and the plurality of accessories are coaxially arranged on both sides of the driven gear. An auxiliary drive device for an engine, characterized in that: