JPH031643Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a final reduction gear for various vehicles such as tractors.

<Prior art> In vehicles such as tractors, for example, the power transmission system from the rear wheel differential device to the left and right rear wheels is equipped with a planetary reduction device for final deceleration.
This is proposed in Publication No. 56-45805. This bulletin,
In addition, the disclosed planetary reduction device has a sun gear fixed to an input shaft such as a differential yoke shaft, and a planetary carrier fixed to an output shaft such as a rear axle, and uses the sun gear for input and the planetary gear for output. is normal.

<Problems to be solved by the invention> However, in the conventional system that uses the sun gear for input and the planetary gear for output,
In order to ensure a sufficient reduction ratio, the diameter of the sun gear must be made small, which has the drawback of causing significant damage to the sun gear. Conversely, if the diameter of the planetary gear is made large without making the diameter of the sun gear small, the planetary carrier and ring gear will become larger and larger, which has the drawback of lowering the ground clearance. Therefore, in the past, although it was a planetary speed reduction device, it was difficult to make it small, have a large speed reduction ratio, and improve durability. In addition, the support of the planetary carrier is also cantilevered,
It was unstable and difficult to assemble.

The present invention provides a final reduction gear that can solve these conventional problems.

<Means for Solving the Problems> The present invention, as a technical means for solving the conventional problems as described above, is provided with a differential output shaft (planetary A brake case 17 having a brake element for braking the input shaft (input shaft) 7 is attached to the device, and a rear axle (output shaft for a planetary device) is attached to the brake case 17 coaxially with the differential output shaft 7. ) 14 is installed, and the differential output shaft 7 and the rear axle 14 are interlocked and connected by a planetary reduction gear 12. A planetary carrier 26 is fixed, and a planetary gear having two gear portions 27 and 28 of different diameters is provided on a support shaft 30 provided on the planetary carrier 26 in parallel with the differential output shaft 7, and the planetary gear 26 is fixed. A fixed ring gear 31 with which the large-diameter gear portion 27 of the gear engages is interposed and fixed between the brake case 17 and the rear axle case 13, and an output ring gear 32 with which the small-diameter gear portion 28 of the planetary gear engages with the rear axle. The output ring gear 32 is fixed to the inner end in the axial direction of the axle 14, and the output ring gear 32 has a bowl-shaped cross section.
The planetary carrier 26 is supported by the bowl-shaped boss portion 34 via a
1 through a bearing 37.

<Operation> When power is transmitted from the input shaft 7, the planetary carrier 26 rotates together with the input shaft 7 in the direction of the arrow a, as shown in FIG. 31, the planetary gear 29 rotates in the direction of arrow b. Therefore,
The output ring gear 32 meshing with the gear portion 28 of the planetary gear 29 rotates in the direction of arrow c, and the output shaft 1
Transmits power to 4.

During this power transmission, the planetary carrier 26 is supported at its outer end in the axial direction by the output ring gear 32 and its inner end in the axial direction by the fixed side, that is, the brake case 17, through bearings 37 and 38, respectively, so that the planetary carrier 26 can be accurately Ensures smooth transmission, no twisting, and improved lifespan.

<Embodiment> Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 denotes a transmission case constituting a tractor body, and a rear wheel differential device 2 is provided at the rear of the transmission case. The differential device 2 includes a bevel gear 3, a differential case 4, a differential pinion 5, a differential side gear 6, a differential yoke shaft 7, and the like. The differential case 4 is rotatably supported by the side wall 10 of the transmission case 1 via bearings 8 and bearing cases 9 on both the left and right sides, and the differential yoke shaft 7 serves as an input shaft. It is made to protrude on both sides. 11 is a hydraulic brake device for braking the differential yoke shaft 7; 12 is a planetary reduction device for final deceleration; 13 is a rear axle (output shaft) 1
4 through a bearing 15,
These are arranged in series on both sides of the transmission case 1, and the fixed plate 16 and brake case 17 of the brake device 11, the reduction case 18 of the planetary reduction device 12, and the rear axle case 13 are connected to the transmission case 1 with bolts 19. It is fastened together to the side wall 10.
The brake device 11 includes a fixed platen 16 and a brake case 17 as well as a spline portion 7 of a differential yoke shaft 7.
Brake plate 20 fitted to a, brake plate 20
A stationary plate 22 is arranged to sandwich the brake plate 20 and the stationary plate 22 is fixed non-rotatably by a pin 21. It includes a plurality of pistons 25 in the circumferential direction that are fitted into the fixed plate 16 so as to force the pistons 25 and the like in the circumferential direction. Planetary reduction gear 12
The planetary carrier 26 has a planetary carrier 26 fitted onto the outer end of the spline portion 7a of the differential yoke shaft 7, and two large and small gear portions 27, 28.
A plurality of circumferential planetary gears 29 are rotatably supported via a support shaft 30, and a fixed ring gear 31 engages with the large gear portion 27 of the planetary gears 29.
and an output ring gear 32 that meshes with the small gear portion 28 of the planetary gear 29. The planetary gear 29 is provided so that the small gear portion 28 side is on the outer side, and the small gear portion 28 is located on the outer peripheral side of the boss portion 33 of the planetary carrier 26. The fixed ring gear 31 is fixed between the brake case 17 and the reduction case 18 by tightening bolts 19 together.
7th grade constitutes the fixed side. The output ring gear 32 is shaped like a bowl, and its boss portion 34 is spline-coupled to the rear axle 14 on the outside of the differential yoke shaft 7, and is prevented from coming off by a retaining plate 35 and bolts 36. The planetary carrier 26 is rotatably supported by the brake case 17, that is, the stationary side, via a bearing 37 on the outer periphery of the axially inner end, and is supported by the boss of the output ring gear 32 via a bearing 38 on the axially outer end. It is rotatably supported by the section 34. That is, the output ring gear 32
is formed into a bowl-shaped cross section, and a planetary carrier 26 is housed within this bowl-shaped portion, and an axially outer end of the carrier 26 is supported by a bowl-shaped boss portion 34 of an output ring gear 32 via a bearing 38. In addition, the rear axle 13
A rear wheel (not shown) is attached to the outer end of the wheel. Note that ball bearings are used for the bearings 37 and 38.

Next, the operation of the above configuration will be explained. When the differential yoke shaft 7 of the differential device 2 rotates in the direction indicated by the arrow a in FIG. 2, the planetary carrier 26 rotates in the same direction. Then, since the large gear portion 27 of the planetary gear 29 is in mesh with the fixed ring gear 31, the planetary gear 29 continues to revolve in the direction of the arrow a while rotating around the support shaft 30 in the direction of the arrow b. On the other hand, the small gear part 28 of the free rotating gear 29 meshes with the output ring gear 34, and the ratio of the number of teeth of the small gear part 28 to the output ring gear 32 and the ratio of the number of teeth of the large gear part 27 to the fixed ring gear 31. Output ring gear 3
2 rotates in the direction of arrow c, and the rotation is caused by the rear axle 14.
It is transmitted to the rear wheels via the.

In this way, a double structure equipped with large and small gear parts 27 and 28 is used as the planetary gear 29,
By using the output ring gear 31 for output, the reduction ratio can be increased compared to the conventional one. Therefore, there is no need to increase the reduction ratio in the main transmission device or the like within the transmission case 1, which also extends the lifespan of the transmission system.
In addition, by using a double-structured planetary gear 29 in the planetary speed reduction device 12 and configuring it as shown, the sun gear that was conventionally required is no longer necessary.
Although a large speed reduction ratio can be achieved, the entire planetary speed reduction device 12 can be made compact, its ground clearance can be increased, and its durability can also be improved. Furthermore, because these configurations work together, the transmission case 1 itself can be made smaller, so it is fully possible to use the transmission case 1 with other specifications, and mass production effects can be expected due to the combination. One side of the planetary carrier 26 is supported by the brake case 17 via a bearing 37, and the other side is supported by the boss portion 34 of the output ring gear 32 on the rear axle 13 via a bearing 38. By supporting at two points, there is no shaft vibration etc. when the planetary carrier 26 rotates.
Stable support is possible and durability is improved.

Note that the planetary gear 29 has large and small gear parts 27 and 2.
In addition to the integrated structure in which the parts 8 are integrated, they can also be made into separate structures as long as they can rotate together.

As shown in FIG. 3, the planetary carrier 26 can sufficiently withstand even just the bearing 38 because the gear portion 27 meshes with the fixed ring gear 31. In addition, if the opposite ends of the differential yoke shaft 7 and the rear axle 14 are fitted to each other so as to be relatively rotatable, the bearing 3
8 can also be omitted. However, by supporting the planetary carrier 26 at both ends with bearings 37 and 38, durability is improved.

<Effects of the invention> According to the invention, the planetary carrier 26 is provided on the input shaft 7 and used for input, and the planetary gear 29 has a double structure having two gear parts 27 and 28, and one of the gears Since the section 27 is engaged with the fixed ring gear 31 and the other gear section 28 is engaged with the output ring gear 32, it is possible to achieve a larger reduction ratio and downsizing compared to conventional planetary reduction gears. It is also possible to improve durability.

Further, since the planetary carrier 26 is supported at both ends in the axial direction via bearings 37 and 38, the rotation is accurate and the life span is improved, and the output ring gear 32 is formed with a bowl-shaped cross section. Since the planetary carrier 26 is housed within this bowl shape,
The fixed ring gear 31, which is compact in the axial direction and engages with the large-diameter gear portion 28 of the planetary gear, is interposed and fixed between the brake case 17 and the rear axle case 13, so the ring gear 31 can be made large in diameter and has a high reduction ratio. can be made large and stable support can be achieved with a simple structure.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is an explanatory diagram of the operation, and FIG. 3 is a sectional view showing a comparative example. 2...Differential device, 7...Differential yoke shaft (input shaft), 11...Brake device, 12...Planetary reduction gear, 13...Rear axle case, 14...Rear axle (output shaft), 17...Fixed side (brake case),
26... Planetary carrier, 27, 28... Gear section, 29... Planetary gear, 31... Fixed ring gear, 32... Output ring gear, 37, 38...
…bearing.

Claims (1)

[Claims for Utility Model Registration] A brake case 17 having a brake element for braking the differential output shaft 7 is attached to the side wall 10 of the vehicle body 1 in which the differential device 2 is built.
The rear axle 1 is coaxial with the differential output shaft 7.
4 is installed, and the differential output shaft 7 and the rear axle 14 are interlocked and connected by a planetary reduction gear 12. , a planetary gear 26 is fixed, and a planetary gear having two gear parts 27 and 28 of different diameters is provided on a support shaft 30 provided on the planetary carrier 26 parallel to the differential output shaft 7, and the planetary gear A fixed ring gear 31 with which the large diameter gear portion 27 of the planetary gear engages is interposed and fixed between the brake case 17 and the rear axle case 13, and an output ring gear 32 with which the small diameter gear portion 28 of the planetary gear engages with the rear axle. The output ring gear 32 has a bowl-shaped cross section, and the axial outer end of the planetary carrier 26 housed in the bowl-shaped portion of the output ring gear 32 is fixed to the axially inner end of the output ring gear 32 .
The axially inner end of the planetary carrier 26 is supported by the bowl-shaped boss portion 34 via the brake case 1.
1. A final reduction gear for a vehicle, characterized in that it is supported by a bearing 37 on a vehicle.