JPH11280489A - Supporting structure for intermediate gear in gear lines - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support structure of an intermediate gear in a gear train for transmitting torque of a crank shaft to a driving shaft which improves supporting rigidity of a support shaft of the intermediate gear in the gear train, suppresses deformation of the support shaft of the intermediate gear, reduces damage of bearings, and reduces gear noises. SOLUTION: Gear lines have at least two intermediate gears 12, 14 for transmitting torque of a crank shaft 21 of an internal combustion engine to a driving shaft 15. The intermediate gears 12, 14 are rotatably supported to support shafts 13, 15 respectively, each of the shafts 13, 15 having one end fixed to a main body 10 of the internal combustion engine. Free ends of the support shafts 13, 15 are connected to each other by means of a connection support plate 40 separated from a cover of a gear case housing the gear train. The connection support plate 40 is fixed and supported to the engine main body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate gear in a gear train for transmitting the rotational force of a crankshaft disposed on the rear or front surface of an internal combustion engine to a drive shaft such as a PTO shaft for taking out the external equipment. Related to the support structure.

[0002]

2. Description of the Related Art The internal combustion engine of a work vehicle is shown in FIGS.
As shown in FIG. 1, an output take-out shaft 15 called a PTO shaft for driving a working device such as an oil pump for driving a mixer of a mixer truck is provided. This PTO shaft 15
An output gear 16 is provided, and a gear train including a plurality of intermediate gears (idle gears) 12 and 14 is provided between the output gear 16 and a crankshaft 21 having a crank gear 22 to drive the PTO shaft 15. . This gear train is generally provided on the rear side or the front side of the internal combustion engine.

Generally, as shown in FIG. 5A, a support shaft (idle gear spindle) 2 of an intermediate gear of these gear trains is provided with a bolt 2a in a positioning hole 3 provided in a cylinder block 10 of the internal combustion engine. The intermediate gear 5 is rotatably supported around the non-rotating support shaft 2 via a bearing 2b or the like.

When an external force F acts on the intermediate gear 5, the support shaft 2 receives the external force F. Since the support shaft 2 is fixedly supported at one end, it is shown in FIG. The bending moment M which deforms the free end side of the tip so as to fall down. That is, the intermediate gear 2
Of the supporting shaft 2 including the bolts 2a against the force F applied to the support shaft 2.

[0005] However, in recent years, the performance of the internal combustion engine has been improved, the output to the PTO shaft has been increased, and the load applied to each gear in the gear train has been increasing. Therefore, the amount of bending deformation of the gear supporting shaft increases with the increase in the load applied to the gear, and the bearing of the bearing supporting the gear is damaged, and the tooth surface contact caused by a slight inclination of the shaft is caused. A problem has arisen that the gear meshing noise caused by such factors increases.

In order to solve these problems, there is a method of increasing the rigidity by increasing the diameter of the support shaft for supporting the intermediate gear to cope with an increase in the force applied to the support shaft. There is a problem that the weight and the size are increased, which causes an increase in the weight of the internal combustion engine and an increase in the manufacturing cost. Also,
As shown in FIG. 6, the support shafts 11 and 13 of the intermediate gears 12 and 14 are not only used on the cylinder block 10 side but also on the cover 51 of the gear case.
There is also a method in which the support shafts 11 and 13 are prevented from bending deformation by supporting the support shafts 11 and 13 at both ends to form a support structure at both ends. However, in this method, in order to center the intermediate gears 12 and 14, it is necessary to provide the position of the bearing hole on the cover 51 exactly in correspondence with the fixing hole on the cylinder block 10 side. Processing technology is required. Therefore, there is a problem that a capital investment for improving the precision of the processing equipment and the like is required, and the manufacturing cost is increased.

Further, in the method of supporting the gear case with the cover 51, the vibration of the intermediate gears 12, 14 is transmitted to the cover 51 of the gear case via the support shafts 11, 13, so that the cover 51 becomes a new noise source. Therefore, there is a problem that engine noise increases. In particular, the gears 12, 14, and 16 in the gear train for driving the PTO shaft 15 have twice or more the drive compared to the gear trains 24 and 26 for driving auxiliary equipment such as cams and pumps. Power is transmitted. Therefore, a large force in the bending direction acts on the support shafts 11, 13 of the intermediate gears 12, 14 of these gear trains.

[0008] The magnitude of this force depends on the driving situation,
For example, the acting force on the camshaft 25 is 20 kg.
f (196 N), while the acting force on the PTO shaft 15 is 40 kg. f (392N). In particular, in the case of a diesel engine, since the torque fluctuation is large, the thrust vibration increases along with the rotation fluctuation of the crankshaft 21, the external force F increases, and the engine noise increases.

Therefore, one of the inventors of the present invention disclosed in Japanese Utility Model Publication No. 58-51380, a plurality of intermediate gears of a gear train on the PTO shaft 15 side with a support plate 30 as shown in FIG.
By connecting and supporting the support shafts 11, 13 of 12, 14, this support shaft
As shown in FIG. 8, this support plate 30 is separated from the cover 50 of the gear case and provided independently to support the transmission of vibration to the cover 50 side of the gear case. A device for supporting the intermediate gear which has been prevented is proposed.

[0010]

However, in this intermediate gear supporting device, when the number of intermediate gears is plural, for example, two, as shown in FIG.
Since the crankshaft 21 receives a reaction force from the output gear 16 of the PTO shaft 15 when the 15 is driven, the forces T1 and T2 act on the support shafts 11 and 13 of the intermediate gears 12 and 14, respectively. Therefore, a rotational moment M1 (= T1 × AB) generated by the couple of T1 and T2 acts on the support plate 30.

For this reason, the tip ends of the support shafts 11, 13 of the two intermediate gears 12, 14 of the same gear train on the side opposite to the cylinder block 10 are connected to the support plate 30 by press fitting (press fitting). Also,
Since the support plate 30 itself is rotationally displaced by the rotational moment M1, the distal ends of the support shafts 11 and 13, ie, the free ends, cannot be completely fixed, and the support shafts 11 and 13 are inclined. Become. This rotation moment M1 is generated by the support plate 30.
Occurs when the number of support shafts of the intermediate gears to be connected with each other is even.

When the number of intermediate gears is odd, for example, three, the reaction forces U1, U2, U3 act on the support plate 31 via the support shafts 61, 63, 65 as shown in FIG. That means
Moreover, since this reaction force is U1 + U3> U2, the support plate
31 is displaced in response to the resultant force U = U1 + U3-U2 in the directions of U1 and U3. The generation of the force in one direction occurs when the number of support shafts of the intermediate gear connected by the support plate 31 is an odd number.

As described above, the intermediate gears 12, 14 in the gear train
Or, in the support plate 30 or 31 that only supports and supports the support shafts 11, 13 or 61, 63, 65 of 62, 64, 66, the reaction forces T1, T2, U1,
Since it is displaced due to the rotational moment M1 and the combined force U by U2 and U3, the support shaft 11, 13 or the support plate side 30 or 31 of the intermediate gear 12, 14 or 62, 64, 66 is fixed. Was insufficient, and it was found that the inclination of the support shafts 11, 13 or 61, 63, 65 could not be completely prevented.

The amount of rotational displacement and the amount of displacement are represented by P
Since it changes depending on the reaction force received from the TO shaft 15, the rotation force of the PTO shaft 15 and the rotation force of the crankshaft 21 which generate these reaction forces change.
Alternatively, there has been a problem that 31 itself vibrates and causes noise.

That is, the intermediate gear (idle gear) of the gear train having a large driving force receives a large load and vibration due to the force on the crankshaft side and the PTO shaft side, so that the supporting rigidity of the intermediate gear is secured. Was a problem.

The present invention has been made in order to solve these problems, and an object of the present invention is to provide a support shaft for an intermediate gear in a gear train for transmitting a rotational force from a crankshaft to a drive shaft. An object of the present invention is to provide a support structure for an intermediate gear in a gear train that can increase the support rigidity and suppress the deformation of the support shaft of the intermediate gear, reduce damage to a bearing portion, and reduce gear noise.

[0017]

According to the present invention, there is provided a device for supporting an intermediate gear of a gear train, comprising two or more intermediate gears for transmitting a rotational force from a crankshaft of an internal combustion engine to a drive shaft. A gear train having gears, wherein each of the intermediate gears is rotatably supported by a respective support shaft having one end fixed to the main body of the internal combustion engine, and free ends of at least two support shafts of the support shaft. The sides are connected to each other by a connecting support plate that is separated and independent from the cover of the gear case that houses the gear train, and the connecting support plate is fixedly supported on the engine body side.

According to this configuration, since the support shafts of the intermediate gears of the gear train of the drive shaft such as the PTO shaft which receive a relatively large rotational load are connected by the connecting support plate, the rigidity of the support shaft is increased and the amount of deformation is reduced. I do. Further, since this connection support plate is directly fixed to the cylinder block by bolting or the like and fixedly supported on the engine body side, a force due to a rotational moment or a reaction force generated in the connection support plate is received by the engine body side. Since the displacement and the vibration of the connecting support plate are stopped, the displacement and the vibration on the tip side of the support shaft are also reduced.

The connecting support plate may be fixed to the engine body by providing a projection projecting toward the engine body and abutting the connecting support plate, or by interposing a spacer between the connecting support plate and the engine body. is there.

However, from the viewpoint of reducing processing on the engine body side, reducing the number of parts, and facilitating assembly, the fixed support portion of the connection support plate to the engine body side is formed from the connection support plate. It is preferable to have a leg that protrudes and comes into contact with the engine body and has a bolt hole.

According to this configuration, the connecting support plate is brought into direct contact with the engine main body side, and the fixing is firm.
The engine body side reliably receives the force and vibration applied to the intermediate gear, thereby preventing the vibration of the intermediate gear.

When the number of the intermediate gears is two, at least a part of the fixed support portion of the connecting support plate to the engine body side is arranged on a perpendicular bisector with respect to the center of both support shafts of the intermediate gear. And configure.

According to this configuration, an isosceles triangle is formed by the support shafts of the first and second intermediate gears and the fixed support on the vertical bisector, so that the two intermediate gears are connected around the mesh point. It can efficiently support the rotational moment of the support plate,
Further, it is possible to prevent the support shaft of the intermediate gear from falling down due to the rotational moment.

That is, when the fixed support is provided on the perpendicular bisector, the force applied to the fixed support is only in the direction parallel to the two support axes, and in the opposite direction on both sides of the two support axes. Therefore, the combined force of the reaction forces of the fixed support portions on both sides is reduced. Furthermore, if the distance between the fixed support portion and the two support axes is equal, a reaction force of the same magnitude and in the opposite direction is generated, and the resultant force is zero.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a support structure for an intermediate gear in a gear train according to the present invention will be described with reference to FIGS. The internal combustion engine of a working vehicle such as a mixer truck, an aerial work vehicle, and a UNIC vehicle drives a working device, for example, an oil pump for driving a mixer of a mixer truck, on the rear side or the front side of the cylinder block 10. For this purpose, a PTO shaft (output extraction shaft) 15 for extracting a part of the output of the internal combustion engine to the outside is provided.

In order to drive the PTO shaft 15, which is the drive shaft, an output gear 16 is provided on the PTO shaft 15, and the output gear 16 and a crank gear of a crank shaft 21 for outputting the driving force of the internal combustion engine. A gear train including a plurality of intermediate gears, such as first and second intermediate gears (idle gears) 12 and 14, is provided between the gear train.

In the embodiment shown in FIGS. 1 and 2, a cam gear 26 for driving a cam shaft 25, a third intermediate gear 24, and a crank gear 22 are provided as another gear train. By this gear train, the rotational force of the crankshaft 21 is transmitted to the camshaft 25.

The rotational force of the crankshaft 21 is transmitted through the third intermediate gear 24 and another intermediate gear (not shown).
It is configured to be transmitted to a fuel injection pump gear, an air compressor gear, and the like (not shown).

The first, second and third intermediate gears 12, 14 and 24 are arranged around a first support shaft (spindle) 11 as shown in the example of the first intermediate gear 12 in FIG. , And is rotatably supported via a bearing 11b. The support shaft 11 is fixed to the cylinder block 10 on the main body side of the internal combustion engine with bolts 11a. 2nd, 3rd intermediate gear 1
4 and 24 have the same structure.

Further, as shown in FIGS. 1 and 2,
The first and second intermediate gears of the gear train are connected support plates 40 provided separately and independently from the cover 50 of the gear case for housing the gear train.
The free ends of the support shafts 11 and 13 that support 12 and 14, that is, the distal ends opposite to the cylinder block 10 side are connected and fixed.

Further, the connecting support plate 40 is connected to the connecting support plate 40.
Legs 70a, 70a, 71a projecting from 40 and abutting on the engine body side 10 and having bolt holes are provided, and bolts 75 are inserted into the bolt holes and fastened and fixed to the engine body (cylinder block) 10 side. .

That is, the one-side fixed state of each of the intermediate gears 12 and 14 is fixedly supported at both ends by the connecting support plate 40, so that the rigidity of each of the support shafts 11 and 13 is enhanced,
The engine body 10 is configured to receive the combined force of the acting force via the connecting support plate 40 on the engine body 10 side. In FIG. 1, the number of the support shafts 11 and 13 of the intermediate gears 12 and 14 of the gear train connected and supported by the connection support plate 40 has been described as two, but if there are many intermediate gears, Two or more may be selected or all may be connected.

With the above configuration, the intermediate gears 12 of the gear train of the drive shaft 15 such as a PTO shaft which receives a relatively large rotational load,
While supporting the 14 support shafts 11 and 13 at both ends to increase rigidity,
Since the connecting support plate 40 is fixedly supported on the engine body side 10,
Displacement and vibration of the connecting support plate 40 can be prevented, and each support shaft 1
Slant deformation of 1 and 13 can be prevented. Therefore, vibration, noise, and wear of the bearing portions 11b and 13b due to the gear train can be reduced.

Further, since the support shafts 11 and 13 of the gear train having different directions and magnitudes of the reaction force received from the respective drive shafts 15 are connected by the connection support plate 40, the force acting on each of the support shafts 11 and 13 is reduced. Once combined, the combined rotational moment and combined force are borne by the connection support plate 40. Therefore, some of the forces acting on each of the support shafts 11 and 13 cancel each other out, so that the support can be efficiently performed.

Further, when there are two intermediate gears 12, 14, the fixed support portions 70, 70, 70, 70,
At least a part 70, 70 of 71 is arranged and arranged on a perpendicular bisector CC with respect to the center A, B of both support shafts of the intermediate gears 12, 14. That is, the support shafts 13 and 15 of the first intermediate gear 12 and the second intermediate gear 14 and the fixed support portion 70 on the perpendicular bisector CC constitute an isosceles triangle, and the connection support plate 40 is fixed. To support.

According to this configuration, when the crankshaft 21 is driven, a reaction force is received from the output gear 16 of the PTO output shaft 15, and T1 and T1 are applied to the support shafts 11 and 13 of the intermediate gears 12 and 14, respectively.
2 (= T1) couple acts and the rotational moment M1 (=
T1 × AB), but the direction of the reaction force of the fixed support portions 70, 70, which opposes the rotational moment M1 about the meshing point P between the first intermediate gear 12 and the second intermediate gear 14, is directed to both support axes AB. It can only be in parallel directions.

Moreover, on the opposite side of the two support axes AB, the direction of the reaction force can be reversed, so that the combined force of the reaction forces of the fixed support portions 70 can be reduced. In addition, when the distance between the fixed support portions 70, 70 and the two support axes AB is made equal, the reaction force can be the same magnitude and the reaction force in the opposite direction. Can be zero.

Accordingly, the rotational moment M1 of the connecting support plate 40 around the meshing point P of the two intermediate gears 12, 14 can be efficiently supported, and the supporting shaft of the intermediate gears 12, 14 caused by the rotational moment M1. It is possible to prevent the connection support plate 40 from being displaced and rocked by preventing the fall of the members 13 and 15.

[0039]

According to the support structure of the intermediate gear of the gear train of the present invention, the following effects can be obtained. Separately and independently from the cover of the gear case that houses the gear train, a connection support plate that connects and supports the free ends of two or more support shafts that support the intermediate gear is provided, and the connection support plate is fixedly supported on the engine body side. Therefore, each support shaft is supported at both ends by a connecting support plate to increase rigidity, and it is possible to reduce deformation, displacement and vibration of the support shaft of the gear train, and to reduce displacement and vibration of the connecting support plate itself. As a result, the inclination of the intermediate gears can be prevented, and damage to the bearing of each intermediate gear and gear noise can be reduced.

Since the connecting support plate is provided independently of the cover of the gear case, the cover is not vibrated, and the noise generated from the connecting support plate can be reduced by the cover. Engine noise can be further reduced.

Further, the fixed support portion of the connecting support plate to the engine body side is formed by protruding from the connecting support plate and abutting on the engine body side, and is provided with a leg portion having a bolt hole. The plate can be brought into direct contact with the engine body side to secure the fixing, so that the force and vibration applied to the intermediate gear can be reliably received by the engine side body, and the intermediate gear and the connection support plate Displacement and vibration can be prevented.

Further, there are two intermediate gears, and at least a part of the fixed support portion of the connecting support plate to the engine main body is arranged on a vertical bisector of the center of both support shafts of the intermediate gear. Because an isosceles triangle was configured with the shaft and the fixed support,
The combined force of the reaction force of the fixed support portion with respect to the rotational moment around the meshing point of the two intermediate gears can be reduced, and the connection support plate can be efficiently supported.

Therefore, by being fixedly supported on the engine body side,
Since the supporting shaft of each intermediate gear is supported by the connecting support plate that prevents displacement and vibration, deformation and vibration of each supporting shaft can be prevented,
Damage to the bearing caused by bending deformation of each support shaft can be reduced, and the durability of the gear train can be improved.
Gear noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing a support structure of an intermediate gear in a gear train according to the present invention.

FIG. 2 is a partial side sectional view taken along line XX of FIG. 1;

FIG. 3 is a front view showing a support structure of an intermediate gear in a gear train of the related art.

FIG. 4 is a side sectional view showing a support structure of an intermediate gear in a gear train of the related art.

5A and 5B are partial side sectional views showing a supporting structure of an intermediate gear in a gear train according to the related art, in which FIG. 5A is a diagram showing a force acting on the gear, and FIG. It is a figure which shows typically.

FIG. 6 is a side sectional view showing a support structure of an intermediate gear in another conventional gear train.

FIG. 7 is a front view showing a support structure for two intermediate gears in a gear train of the improved technique.

FIG. 8 is a partial side sectional view of FIG. 7;

FIG. 9 is a front view showing a support structure for three intermediate gears in a gear train of the improved technology.

[Explanation of symbols]

10 Cylinder block 11, 13, 23, 61, 6
3, 65 Support shaft 11a, 13a, 23a, 61a, 63a, 65a Bolt 11b, 13b, 23b, 61b, 63b, 65b Bearing Bearing 12, 14, 24, 62, 64, 66 Intermediate gear (idle gear) 15 PTO shaft (Drive shaft) 16 Output gear 21 Crank shaft 22 Crank gear 25 Cam shaft 26 Cam gear 30, 31 Support plate 40 Connection support plate 50 Gear case cover 70, 71 Fixed support 70a, 71a Leg 75 bolt

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kenichi Yanagihara 3-25-1, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Isuzu Motors Corporation Kawasaki Plant

Claims (3)

[Claims] 1. A gear train having two or more intermediate gears for transmitting a rotational force from a crankshaft of an internal combustion engine to a drive shaft, wherein one end of each of the intermediate gears is fixed to a main body side of the internal combustion engine. Each of the support shafts is rotatably supported, and the free end sides of at least two support shafts of the support shaft are connected to each other by a connection support plate separated and independent from a cover of a gear case that houses the gear train, Further, a supporting structure for an intermediate gear in a gear train, wherein the connecting support plate is fixedly supported on an engine body side. 2. The fixed support portion of the connection support plate on the engine body side has a leg portion protruding from the connection support plate and abutting on the engine body side and having a bolt hole. The support structure for an intermediate gear in a gear train according to claim 1. 3. When two intermediate gears are provided, at least a part of the fixed support portion of the connecting support plate on the engine body side is arranged on a bisector perpendicular to the center of both support shafts of the intermediate gear. The support structure for an intermediate gear in a gear train according to claim 1 or 2, wherein: