JPH0220521Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a traveling drive device for a crawler vehicle such as a hydraulic excavator, a hydraulic crane, etc.

For example, a crawler vehicle such as a hydraulic excavator or a hydraulic crane is equipped with a crawler track for traveling on an endless track, the crawler belt is wound around a sprocket, and the vehicle is driven by rotationally driving the sprocket. A hydraulic motor is provided to drive the sprocket, and the rotational output of the hydraulic motor is reduced in speed by a speed reduction device equipped with a planetary gear mechanism and transmitted to the sprocket.

Therefore, FIG. 1 shows a conventional crawler vehicle travel drive system.

In the figure, 1 indicates a hydraulic motor for traveling, 2 indicates a rotating shaft of the hydraulic motor 1 as a drive shaft,
The rotating shaft 2 is provided to protrude into a casing 3 of the speed reduction device. Reference numeral 4 designates a shaft as an input shaft that is spline-coupled with the rotating shaft 2 through a spline groove 4A and rotates together with the rotating shaft 2, and a gear is engraved at the tip of the shaft 4 to form the first sun gear 5. has been done. A first planet gear 6 meshes with the first sun gear 5,
The first planet gear 6 also meshes with a ring gear 7 carved into the inner wall of the casing 3. As a result, when the first sun gear 5 is rotated, the first planet gear 6 rotates and the first sun gear 5 rotates.
It revolves around sun gear 5. A pin 9 is inserted through the first planet gear 6 via a bearing 8, and a first carrier 10 is fitted into the pin 9. Only the revolution of the planet gear 6 is transmitted,
The first carrier 10 is rotated at a reduced speed according to the gear ratio between the first sun gear 5 and the first planet gear 6. This is the first stage planetary gear mechanism.

Next, reference numeral 11 indicates a second sun gear, and the second sun gear 11 meshes with an internal gear 10A formed at the rotation center of the first carrier 10, and follows the rotation of the first carrier 10. It is supposed to rotate. Further, 12 indicates a second planet gear, and the second planet gear 12 meshes with the second sun gear 11 and also meshes with the ring gear 7. When the second sun gear 11 rotates, the second planet gear 12 is caused to revolve around the second sun gear 11 while rotating.
Furthermore, the second planet gear 12 has a bearing 1.
A pin 14 is inserted through the pin 3, and a second carrier 15 is fitted onto the pin 14. As a result, the second carrier 15 is rotated at a reduced speed according to the ratio of the number of teeth between the second sun gear 11 and the second planet gear 12. This is the second stage planetary gear mechanism.

Reference numeral 16 indicates a pinion as an output shaft spline-coupled to the second carrier 15, and the pinion 16 is connected to a bearing 20 provided on the frame 18 to which the casing 3 is attached via bolts 17, 17, and on the support member 19. 21, and the pinion 16 meshes with a gear 22 that drives a sprocket disposed between the frame 18 and the support member 19. The rotation of the rotating shaft 2 is reduced in two steps by the aforementioned planetary gear mechanism and then transmitted to the pinion 16, and the gear 22, which drives a sprocket provided by winding a track (not shown) around the outer circumference, is rotationally driven. It is designed to be forced. Then, the casing 3 is attached to the frame 18
By being attached to it, they become an integral fixed member.

Here, a shaft 4 including a first sun gear 5, a first carrier 10, a second sun gear 11,
The second carrier 15 and pinion 16 are arranged on the same axis A--A.

Next, 23 indicates a multi-disc brake, and the multi-disc brake 23 includes an annular brake plate 24 spline-coupled to the spline groove 4A of the shaft 4, and an annular brake plate 24 spline-coupled to the spline groove 25 formed in the casing 3. It is formed by alternately arranging brake plates 26 in parallel while partially facing each other, and among the brake plates 24 and 26, the one disposed at the leftmost end in the figure is in contact with the plate 27 attached to the casing 3. The plate 27 is configured to be able to come into contact with a presser plate 28 fixedly provided to the casing 3. On the other hand, a plate 29 is disposed adjacent to the rightmost brake plate 24 in the figure, and the plate 29 meshes with the spline groove 25. By pressing the plate 29 to the left in the figure, the brake plates 24 and 26 are brought into frictional engagement between the plates 29 and 27, thereby holding the shaft 4 in a non-rotating state. It's becoming like that. The mechanism for pressing the plate 29 includes a piston 30 and a piston 3.
0 to the left in the figure and keeps the plate 29 in a braking state at all times, and the piston 3.
a pressure chamber 32 that is formed within the pressure chamber 32 and displaces the piston 30 in a direction against the biasing force of the disk spring 31 to release the brake, and an oil passage 33 that supplies hydraulic pressure into the pressure chamber 32. It consists of

In addition, 34 in the figure indicates the first carrier 10 and the pin 9.
and the pin 9 is inserted between the first carrier 1 and the pin 9.
A locking pin 35 for fixing to the second carrier 15 is inserted between the second carrier 15 and the pin 14, and locking pins 36, 36 are for fixing the pin 14 to the second carrier 15. A retaining ring for positioning the first carrier 10 that is fixed to the second sun gear 11 is shown.

A crawler vehicle travel drive system according to the prior art has the above-mentioned configuration, and its operation will be explained next.

First, hydraulic pressure is introduced into the pressure chamber 32, and the piston 30 is displaced to the right in the figure to bring the multi-disc brake 23 into a brake-released state. When the hydraulic motor 1 is driven in this state, the rotating shaft 2 is rotationally driven, and the shaft 4 connected to the rotating shaft 2 is rotated accordingly. A first sun gear 5 formed at the tip of the shaft 4 meshes with a first planet gear 6, and the first planet gear 6 also meshes with a ring gear 7 fixedly provided on the casing 3. Therefore, the first planet gear 7 revolves around the first sun gear 5 while rotating on its own axis due to the rotation of the first sun gear 5. The revolution of the first planet gear 6 is transmitted to the first carrier 10 via the pin 9. As a result, the first carrier 10 is decelerated at a predetermined ratio with respect to the first sun gear 5 and rotationally drives the second sun gear 11 connected to the first carrier 10, so that the deceleration effect of the first stage is activated. It is done.

Next, when the second sun gear 11 rotates, the second planet gear 12 meshing with the second sun gear 11 and the ring gear 7 revolves around the second sun gear 11 while rotating. This revolution of the second planet gear 12 rotationally drives the second carrier 15 via the pin 14. As a result, the second carrier 15 is decelerated at a predetermined ratio with respect to the second sun gear 11, and the pinion 16 connected to the second carrier 15 is rotationally driven, thereby performing a second-stage deceleration effect. In this way, the gear 22, which is decelerated in two stages and drives the sprocket by the pinion 16, is rotationally driven.

On the other hand, when the vehicle is stopped, the hydraulic pressure in the pressure chamber 32 is discharged, and the piston 30 is displaced to the left in the figure by the biasing force of the disc spring 31, and the plate 29 is pressed by the piston 30, causing the brake plate 24, 26
is held between the plates 29 and 27. As a result, the shaft 4 is held in a non-rotating state by the frictional force between the brake plates 24 and 26, and the stopped vehicle is prevented from running unnecessarily.

By the way, when a large external force is applied to the vehicle while the vehicle is running, this external force is transmitted from the gear 22 that drives the sprocket to the pinion 16, causing the pinion 16 to deflect. For this purpose, the second carrier 15, which engages the pinion 16, is inclined with respect to the axis A--A. Since the second carrier 15 supports the pin 14 and the second planet gear 12 fitted to the pin 14, the axis of the second planet gear 12 is eccentric with respect to the axis. As a result, the tooth surface pressure at the meshing portion between the second planet gear 12, the second sun gear 11, and the ring gear 7 provided in the casing 3 increases, and uneven contact occurs on the tooth surfaces, causing premature damage to the tooth surfaces. This has the disadvantage of causing wear and tear and unequal distribution of power. Also, pin 14
The contact pressure of the bearing 13 interposed between the second planet gear 12 and the second planet gear 12 also increases, which has disadvantages such as lowering the strength of the bearing 13 and shortening its life.

Furthermore, since the ring gear 7 and the spline groove 25 are formed directly on the casing 3, the stroke of the cutter is lengthened when cutting the ring gear 7 and the spline groove 25.
The tooth tip must be inserted deep into the casing 3 for processing. For this reason, machining of the teeth of the ring gear 7 and the spline groove 25 becomes difficult, and machining distortion is likely to occur. There are also drawbacks that can lead to bias.

The present invention was developed in view of the above-mentioned drawbacks of the prior art, and is designed to ensure smooth engagement between the planet gear and ring gear of a planetary gear mechanism even when a large external force is applied to the output shaft, and to connect the ring gear and multi-disc brake. An object of the present invention is to provide a traveling drive device for a crawler vehicle that allows easy machining of spline grooves.

In order to achieve the above-mentioned object, the feature of the configuration adopted in the present invention is that one axial side is fixed to the fixed casing to form a fixed end in the fixed casing that houses the reduction gear and the multi-disc brake, and the other axial side is fixed to the fixed casing. A cylindrical bracket made of a separate member having a free end with a radial gap between the side and the fixed casing is disposed, and a planet of the speed reduction device is disposed on the inner circumferential surface of the bracket at the free end side. A ring gear that meshes with the planet gear of the gear mechanism is formed, and a spline groove is formed on the fixed end side for spline connection with one of the brake plates of the multi-disc brake.

With this configuration, a gap is secured between the free end side of the cylindrical bracket and the fixed casing, so that even if a large external force acts on the output shaft and the output shaft is bent, the bracket remains free. Since the external force can be compensated by deforming the end side, the meshing state of the planet gear and ring gear is maintained properly, and the tooth surface pressure of these meshing parts is prevented from abnormally increasing and uneven contact. Ru. Furthermore, since the bracket only needs to be machined by gear cutting between the ring gear and the spline groove, the machining becomes easy and the occurrence of machining distortion is prevented.

Hereinafter, an embodiment of the present invention will be described based on FIG. In this figure, the same components as those in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted.

However, 41 indicates a cylindrical bracket disposed within the casing 3, and the bracket 41 has a diameter smaller than the inner peripheral surface of the large diameter portion of the casing 3 in which the first stage and second stage planetary gear mechanisms are disposed. a large-diameter cylindrical portion 41A having an outer circumference, a small-diameter cylindrical portion 41B having an outer circumferential surface approximately the same as the inner circumferential surface of the small-diameter portion of the casing 3 in which the multi-disc brake 23 is disposed, and each of the cylindrical portions 4.
It is composed of a stepped portion 41C that connects 1A and 41B. A ring gear 42 that meshes with the first and second planet gears 6 and 12 is carved on the inner circumferential surface of the large diameter cylindrical portion 41A, and a multi-disc brake 23 is formed on the inner circumferential surface of the small diameter cylindrical portion 41B. A spline groove 43 is cut into which the brake plate 26 and plate 29 that make up the brake plate 29 are connected. Also,
A bolt 44 is attached to the stepped portion 41C, and the bracket 41 is fixed to the casing 3 via the bolt 44. Thus, the bracket 41
The small diameter cylindrical portion 41B on one side in the axial direction is a fixed end fixed to the casing 3 by the bolt 44, and the other axial side, which is the large diameter cylindrical portion 41A, is a free end. Between the outer peripheral surface of the portion 41A and the inner peripheral surface of the large diameter portion of the casing 3,
As shown in the figure, a gap in the radial direction is ensured. In this embodiment, the casing 3 is not provided with a ring gear or spline groove according to the prior art.

Further, 45 indicates a second carrier, and the second carrier 45 is connected to a hub member 47 fitted to the pinion 16 via a coupling member 46. The second carrier 45 and the hub member 47 are connected to the coupling member 46, and the hub member 47 and the pinion 16 are connected by spline connections.

The present invention has the above-mentioned configuration, and the rotating shaft 2
There is no difference from the prior art in that the power is reduced by a two-stage planetary gear mechanism and transmitted to the pinion 16, and the pinion 16 rotationally drives the gear 22 that drives the sprocket.

However, when a large external force acts on the gear 22 that drives the sprocket, the pinion 16 that meshes with the gear 22 is pressed in the tangential direction of the gear 22.
As a result, the pinion 16 is bent, and the hub member 47
is displaced in a direction oblique to the axis A-A.
However, the hub member 47
Since the coupling member 46 is spline-coupled to the second carrier 45, the displacement of the hub member 47 is compensated for by the backlash and clearance in these spline-coupled parts, and the second carrier 45 is spline-coupled. The structure is such that it does not have much effect on the 45. However, when an extremely large external force acts on the gear 22, the second carrier 45 is inclined with respect to the axis AA. As a result, the axis of the second planet gear 12 that meshes with the second carrier 45 is eccentric.

However, this embodiment has a cylindrical bracket 41 made of a separate member from the casing 3, and the stepped portion 41C of the bracket 41 is fixed to the casing 3 with bolts 44, and the large diameter cylindrical portion 41A becomes a free end and is attached to the large diameter bracket 41. A gap is formed between the outer peripheral surface of the diameter cylindrical portion 41A and the inner peripheral surface of the casing 3. In this embodiment, unlike the conventional ring gear, the ring gear 42 is formed in the large diameter cylindrical portion 41A, so that the large diameter cylindrical portion 41A is deformed in accordance with the eccentricity of the second planet gear 12. This compensates for the eccentricity. Therefore, the second planet gear 12 maintains a proper meshing state with the second sun gear 11 and the ring gear 42, and the second planet gear 12 rotates smoothly. As a result, the power transmitted from the planetary gear mechanism to the pinion 16 is not unevenly distributed, and the tooth surface pressure at the meshing portion between the second planet gear 12, the second sun gear 11, and the ring gear 42 is increased. There is no possibility that uneven contact will occur and wear of the tooth surface will be accelerated. Furthermore, since the axis of the pin 14 connecting the second planet gear 12 and the second carrier 45 is not eccentric, the bearing 1
The contact pressure between the bearing 3 and the pin 14 does not become abnormally high, the strength of the bearing 13 is maintained well, and its lifespan is not reduced.

Next, the ring gear 42 and the spline groove 43
Since these are carved on the bracket 41 which is separate from the casing 3, the bracket 41 can be previously machined with these gears and then fastened to the casing 3 with the bolts 44. Therefore, the stroke of the cutter for gear cutting can be shortened, and not only is the workability excellent, but there is no risk of machining distortion. 6,1
The meshing state with 2 becomes smooth, and there is no uneven contact between them.

In the above embodiment, the power of the drive shaft is decelerated in two stages by a planetary gear mechanism and then transmitted to the output shaft. You can also use Further, although the second carrier 45 is configured to be connected to the pinion 16 via the coupling member 46 and the hub member 47, the second carrier may be configured to be connected directly to the pinion 16.

As explained in detail above, according to the traveling drive device for a crawler vehicle according to the present invention, one axial side is fixed within the fixed casing, and the other axial side has a radial gap between it and the fixed casing. A cylindrical bracket is provided, and the inner peripheral surface of the bracket is provided with a ring gear that meshes with the planet gear on the free end side, and a spline groove that is spline-coupled with the brake plate on the fixed end side. It has the effect of term.

Even if a large external force acts on the output shaft through the gear meshing with the sprocket and the planet gear of the planetary gear mechanism is eccentric, the free end side of the bracket deforms in the radial direction to compensate for the eccentricity of the planet gear. This prevents the tooth surface pressure at the meshing portion between the planet gear and the ring gear from becoming abnormally high or uneven contact between the tooth surfaces, thereby preventing wear and damage on the tooth surfaces.

As described above, since the planet gear can rotate smoothly, the power transmitted from the planetary gear mechanism to the sprocket is not unevenly distributed, and smooth power transmission is possible.

In relation to the above item, since the contact surface pressure between the pin supporting the planet gear and the bearing is not increased abnormally, the strength of the bearing can be maintained at a good level and its life can be prevented from being shortened.

As a result of the above, since the tooth surface pressure at the meshing part between the planet gear and the ring gear and the contact surface pressure between the pin and the bearing that support the planet gear are not increased, the temperature of the lubricating oil in the reduction gear is prevented from rising. Ru.

Since the ring gear and the spline groove are formed in a bracket separate from the casing, machining is easy, and the ring gear and planet gear can be properly engaged without causing any processing distortion in the teeth. This can prevent uneven contact from occurring during that time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a crawler vehicle traveling drive device according to the prior art, and FIG. 2 is a longitudinal cross-sectional view showing a crawler vehicle travel drive device according to the present invention. 2... Rotating shaft, 3... Casing, 4... Shaft, 5... First sun gear, 6... First planet gear, 8, 13... Bearing, 9, 14... Pin, 10... Third 1 carrier, 11...second sun gear, 12...second planet gear, 16...
...pinion, 22...gear, 23...multi-plate brake, 24,26...brake plate, 27,29...
Plate, 30... Piston, 31... Disk spring, 41... Bracket, 42... Ring gear, 43... Spline groove, 44... Bolt.

Claims (1)

[Scope of utility model registration request] A speed reduction device consisting of a planetary gear mechanism is provided within the fixed casing, an input shaft connected to a drive shaft of a hydraulic motor is provided on one axial side of the reduction device, and an output shaft is provided on the other axial side of the reduction device. A gear for transmitting output rotation to a sprocket that drives the shoe body is provided in mesh with the output shaft, and brake plates facing each other are provided in the fixed casing to apply braking to the input shaft. In the travel drive device for a crawler vehicle, which is provided with a multi-disc brake, the fixed casing has one axial side fixed to the fixed casing to form a fixed end, and the other axial side fixed to the fixed casing in the radial direction. A cylindrical bracket having a free end with a gap of A traveling drive device for a crawler vehicle, characterized in that a spline groove is formed for spline connection with one of the brake plates of the multi-plate brake.