JP2000108697A - Gear transmitting structure of traveling transmission gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitting structure for shifting a gear by hydraulic pressure with a simple structure having a small number of part items by forming an oil chamber between a support shaft and a gear fitted thereon so as to be capable of shifting, and shifting the gear by the pressure oil supplied to the oil chamber through an oil passage formed within the support shaft. SOLUTION: Stepped part opposed in axial center direction are formed on the inside surface of each side clutch gear 22 and the outside surface of a support shaft 21 to form an oil chamber 24 between each side clutch gear 22 and the support shaft 21. A pair of oil passage 26 communicating with each of lateral oil chambers 24 is formed within the support shaft 21. A pressure oil is supplied to and discharged from the oil chamber 24 through the oil passages 25, whereby the side clutch gear 22 is shifted to a 'clutch-in' position where it is energized and engaged with a center gear 15 and a 'clutch-off' position where it is forcedly separated form the center gear 15. According to this structure a hydraulically shifting structure can be provided only by forming stepped parts on the inside surface of each side clutch gear 22 and the outside surface of the support shaft 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear transmission structure of a traveling transmission device used for a working machine such as an agricultural machine.

[0002]

2. Description of the Related Art In a gear transmission structure of a traveling transmission device, a structure for shifting gears is often incorporated for shifting or intermittent power, and the gear is shifted by manual operation force or hydraulic operation force. It is carried out.

As a structure for shifting a gear using hydraulic pressure, a structure in which a shift fork of a gear is operated by a piston of a hydraulic cylinder attached to a transmission case, or a ring-shaped support shaft supporting the gear is used. A shift operation is known in which an end of a gear is pressed against the end of a gear with a piston.

[0004]

However, the former structure, in which a hydraulic cylinder is separately provided, has a complicated structure, has many components, requires a lot of trouble in assembling, and increases costs. In addition, the latter structure with a piston inside has fewer parts compared to the former structure and the structure is simplified, but a separate structure for forming a cylinder chamber for accommodating the piston is required, and there is room for improvement. was there.

SUMMARY OF THE INVENTION It is a main object of the present invention to provide a transmission structure in which a gear is shifted by hydraulic pressure with a very simple structure and few components.

[0006]

Means for Solving the Problems [Structure, operation and effect of the invention according to claim 1]

(Structure) In the gear transmission structure for a traveling transmission according to the first aspect of the present invention, an oil chamber is formed between a support shaft and a gear externally fitted to the support shaft so as to be shiftable, and an oil chamber is formed in the support shaft. The gear is shifted by pressure oil supplied to the oil chamber via the formed oil passage.

(Operation) According to the above configuration, a structure for shifting the hydraulic pressure of the gear is formed only by performing step processing for forming an oil chamber on the inner peripheral surface of the gear and the outer peripheral surface of the support shaft.

(Effects) Therefore, according to the first aspect of the present invention, there is no need for a shift fork or a piston for shifting gears, and a transmission structure for shifting gears by hydraulic pressure with a simple structure having a small number of parts is provided. Could be provided.

[Structure, operation and effect of the invention according to claim 2]

(Structure) According to a second aspect of the present invention, in the first aspect of the invention, the gear and the support shaft are directly slidably fitted without interposing a seal ring.

(Operation) According to the above configuration, even if the pressure oil leaks from the sliding portion between the gear and the support shaft, it is sufficient that the oil chamber has enough hydraulic pressure to shift the gear. By maintaining the gear, the gear can be held at a predetermined shift position, and the inner peripheral surface of the gear and the outer peripheral surface of the support shaft need only be machined with an accuracy that does not support sliding. Also, there is no need to consider the wear of the seal ring.

(Effects) Therefore, according to the second aspect of the present invention, while the gears can be hydraulically shifted as desired, the processing of the seal ring groove for sealing the oil chamber and the assembly of the seal ring are performed. Is unnecessary, and claim 1
The above-mentioned effect of the invention of the invention is further promoted.

[Structure, operation and effect of the invention according to claim 3]

(Structure) According to a third aspect of the present invention, in the second aspect of the present invention, the tolerance of the sliding portion between the gear and the support shaft is determined by adjusting a part of the pressure oil supplied to the oil chamber. It is set so that a small gap that can flow out is formed.

(Operation) According to the above configuration, the pressure oil forcibly flowing through the minute gap formed at the sliding portion with the gear support shaft causes the gear to float from the support shaft, and the shift resistance of the gear is reduced. Is reduced.

(Effects) Therefore, according to the third aspect of the invention, gear shifting can be performed smoothly without increasing the hydraulic pressure, and the operating performance can be improved.

[Structure, operation and effect of the invention according to claim 4]

(Structure) According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the gear is externally fitted so as to be shiftable on a support shaft of a central gear driven to shift. The left and right side clutch gears are engaged or disengaged from the side of the central gear from the side to transmit or cut off the power of the central gear to the left and right axles for driving the crawler traveling device.

(Operation) According to the above configuration, the left and right side clutch gears are engaged with the central gear, and the power of the same speed is transmitted to the left and right axles for driving the crawler traveling device, so that the aircraft travels straight. When one of the side clutch gears is hydraulically shifted and disengaged from the central gear, the aircraft can be steered. At this time, the side clutch gear is shifted by supply and discharge of pressure oil through an internal oil passage formed on the support shaft of the central gear.

(Effects) Therefore, according to the invention of claim 4, a shift fork or a dedicated piston for hydraulically shifting the side clutch gear is not required, and
The above-described effect of any one of claims 1 to 3 can be obtained, and a steering gear transmission structure that shifts the side clutch gear by hydraulic pressure can be configured with a simple structure having a small number of parts.

[0022]

FIG. 1 shows a self-removing combine as an example of a working machine having a gear transmission structure of a traveling transmission according to the present invention. The combine has a structure in which a mowing unit 3 is connected to a front portion of a traveling machine body 2 having a pair of right and left crawler traveling devices 1 so as to be able to be driven up and down by a hydraulic cylinder 4.
A threshing device 5, a grain recovery unit 6, an engine 7, an operation unit 8, and the like are mounted, and the reaping unit 3 includes:
A plurality of raising devices 9, a clipper-type cutting device 10 for cutting the raised grain culm, and a threshing device 4 for cutting the cut culm.
And a supply / conveyance device 11 that conveys the data toward the vehicle.

FIG. 2 shows a drive structure of the traveling device 1. That is, the power from the engine 7 is transmitted to the hydrostatic type continuously variable transmission (HST) 12 by a belt,
The transmission output of the continuously variable transmission 12 is the transmission case 1
3 is input. The forward or reverse speed change power input to the transmission case 13 is transmitted to a central gear 15 after being shifted to a third speed by a gear shift type auxiliary transmission mechanism 14, and transmitted from the central gear 15 via left and right side clutches 16. The power branched right and left is output to the left and right axles 18 via the reduction gear mechanism 17, and the left and right crawler traveling devices 1 are driven at the same speed. The shifting power of the continuously variable transmission 12 input to the transmission case 13 is output to the work power take-out shaft 19 without passing through the auxiliary transmission mechanism 14, and only the forward power is transmitted via the one-way clutch 20. And transmitted to the mowing unit 3.

As shown in FIG. 4, each side clutch 16
Shifts the side clutch gear 22 loosely fitted to the support shaft 21 of the center gear 15 to the center gear side so as to be engaged with the center gear 15 to bring the clutch into engagement, and shift away from the center gear 15. By disengaging the engagement, a "clutch disengaged" state is brought about, and the slide 23 is urged by the spring 23 toward the "clutch engaged" side. The side clutch gears 22 are maintained in engagement with the reduction gear mechanism 17 irrespective of the left / right shift for engaging / disengaging the clutch, and the interlocking connection between the axles 18 and the side clutch gears 16 is maintained.

Steps are formed on the inner peripheral surface of each side clutch gear 22 and the outer peripheral surface of the support shaft so as to oppose each other in the axial direction. An oil chamber 24 is formed, and a pair of oil passages 25 communicating with the left and right oil chambers 24 are formed inside the support shaft 21. The clutch gear 22 is shifted to a “clutch-in” position in which the clutch gear 22 is biased and engaged with the center gear 15 and a “clutch-off” position in which the clutch gear 22 is forcibly disengaged from the center gear 15.

On the left and right sides of the support shaft 21 of the central gear 15, there are provided respective body steering gears 26 in which the side clutch gears 22 shifted to the "clutch disengagement" position are engaged. The direction gear 26 is always engaged with an intermediate gear 28 spline-connected to the intermediate shaft 27.

The intermediate shaft 27 is loosely fitted with a reduction gear 29 interlocked with the central gear 15, and a hydraulic multi-plate loose coupling for connecting and integrally connecting the reduction gear 29 and the intermediate shaft 27. A turning clutch 30 is provided, and when the slow turning clutch 30 is in the “engaged” state, the power of the reduced forward rotation (in the same direction as the rotation direction of the central gear) is reduced via the left and right reduction gears 29. Is transmitted to the respective body steering gears 26.

At the end of the intermediate shaft 27, a multiple disc type turning brake 31 for braking the intermediate shaft 27 is provided. The turning brake 31 is incorporated in a hydraulic unit 32 attached to a side surface of the transmission case 13, and is braked by displacing a ring-shaped piston 33 rightward in the figure by hydraulic pressure. The braking is released by releasing the hydraulic pressure application.

FIG. 3 shows a hydraulic circuit for operating the oil chamber 24, the gentle turning clutch 30, and the turning brake 31. That is, the pressure oil from the pump P driven by the engine 7 is selectively supplied to the oil chamber 24 for operating the side clutch via the steering valve 34, and the pressure oil supplied to the oil chamber 24 The supply hydraulic pressure is set by a valve 35.
Then, when the gentle turning clutch 30 and the turning brake 31 are connected to the oil passage 36 connected to the lower side of the sequence valve 35 via the direction switching valve 37,
The oil pressure in the oil passage 36 can be adjusted by a variable relief valve 38.

The steering valve 34, the direction switching valve 37, and the variable relief valve 38 are provided in the hydraulic unit 32, and the steering valve 34 is a single steering lever provided in the operating unit 8. The steering lever 41 and the variable relief valve 38 are connected to the wire 41 with a predetermined flexibility. The direction switching valve 37 is connected to a turning mode switching lever 42 provided in the operating unit 8 by wire.

The steering lever 41 is provided so as to be able to swing left and right. In the operating positions L1 and R1 in which the steering lever 41 is swung left or right one step from the neutral position N, only the steering valve 34 is steered left. Position or right steering position,
The operating pressure of the variable relief valve 38 is maintained at zero or an extremely low pressure close thereto. When the steering lever 41 is further pivotally operated to the operation positions L2 and R2 beyond the operation positions L1 and R1, the steering valve 34 is switched to the left steering position or the right steering position, and is changed. Relief valve 3
8 is adjusted to be higher.

The turning mode switching lever 42 is
The oil path 36 is connected to the gentle turning clutch 30 by being switched to the “slow turning” position, and the oil path 36 is connected to the turning brake 3 by being switched to the “rapid turning” position.
The vehicle steering operation according to the selected turning mode will be described below.

[Slow turning mode] In the slow turning mode in which the turning mode switching lever 42 is switched to the "slow turning" position and the oil path 36 is connected to the slow turning clutch 30, the following body steering is performed. Will be

When the steering lever 41 is held at the neutral position N, the steering valve 34 is also at the neutral position, and the oil chambers 24 of the left and right side clutches 16 are in the oil discharging state. Accordingly, the left and right side clutch gears 22 are biased and shifted to the "clutch-engaged" position by the springs 23, and the left and right crawler traveling devices 1 are driven in the same direction at the same speed, so that the straight running state of the body appears.

When the steering lever 41 is swung one step to the left or right operation position L1, R1, the steering valve 34 is switched to the left steering position or the right steering position, and the side on the inner side of the turn is turned. Pressure oil is supplied to the oil chamber 24 of the clutch 16, and the side clutch gear 22 is hydraulically shifted to the “clutch disengaged” position against the spring 23 and meshes with the body steering gear 26. At this time, the oil pressure acting on the oil chamber 24 is maintained at the pressure set by the sequence valve 35. However, since the oil pressure in the inferior oil passage 36 is still an extremely low pressure, the oil pressure selectively connected to the oil passage 36 is low. The turning clutch 30 is in a “clutch disengaged” state, and the intermediate gear 28 and the left and right body steering gears 26 are in a free state. Therefore, the side clutch gear 2 engaged with the body steering gear 26
2 is idle, the crawler traveling device 1 on the side where the side clutch 16 is disengaged enters the idle state, and the body is driven to the left or right by only the crawler traveling device 1 on the side where the side clutch 16 is not disengaged. Will be steered slowly.

When the steering lever 41 is further swung left or right beyond the operating positions L1 and R1, the steering valve 34 is switched to the left steering position or the right steering position. The operating pressure of the variable relief valve 38 is increased and adjusted, and the gentle turning clutch 30 is brought into the “clutch engaged” state, and the one side clutch gear 22 disengaged from the central gear 15 is subjected to reduced forward rotation (rotation of the central gear 15). (Same direction as the direction) is transmitted via the body steering gear 26. As a result, a speed difference is forcibly generated between the left and right crawler traveling devices 1, and the aircraft turns to the side where the side clutch 16 is disengaged.

[Sudden turning mode] In the gentle turning mode in which the turning mode switching lever 42 is switched to the "rapid turning" position and the oil path 36 is connected to the turning brake 31, the following body steering is performed. .

When the steering lever 41 is held at the neutral position N, the steering valve 34 is also at the neutral position, and the left and right side clutches 16 are in the "clutch engaged" state, as in the case of the gentle turning mode. The left and right crawler traveling devices 1 are driven in the same direction at the same speed, and a straight forward state of the machine body appears.

When the steering lever 41 is swung one step to the left or right operating position L1, R1, the steering valve 34 is switched to the left steering position or the right steering position, and the side on the inner side of the turn is turned. Pressure oil is supplied to the oil chamber 24 of the clutch 16, and one of the side clutch gears 22 is hydraulically shifted to a “clutch disengaged” position against the spring 23 and meshes with the body steering gear 26. At this time, the oil pressure acting on the oil chamber 24 is maintained at the pressure set by the sequence valve 35. However, since the oil pressure in the inferior oil passage 36 is still an extremely low pressure, the oil pressure selectively connected to the oil passage 36 is low. Swivel clutch 3
0 is in a "clutch disengaged" state, and the intermediate gear 28 and the left and right body steering gears 26 are in a free state. Therefore,
Also in this case, similarly to the case of the gentle turning mode, the side clutch gear 22 engaged with the fuselage steering gear 26 can rotate freely, and the crawler traveling device 1 on which the side clutch 16 is disengaged rotates freely. State and the side clutch 16
The body is gently steered left or right by driving only the crawler traveling device 1 on the side where is not cut.

When the steering lever 41 is further swung left or right beyond the operation positions L1 and R1, the steering valve 34 is switched to the left steering position or the right steering position. The operating pressure of the variable relief valve 38 is increased and adjusted, the turning brake 31 enters the “braking” state, and the fuselage steering gear 26 is fixed. Therefore, in this case, the one side clutch gear 22 disengaged from the central gear 15 and engaged with the body steering gear 26 is also fixed, so that the crawler traveling device 1 inside the turning is fixed and the crawler traveling device outside the turning is fixed. Only the vehicle 1 is driven, and the aircraft turns sharply to the side where the side clutch 16 is disengaged by one-brake turning.

Here, the turning brake 31 is brought into a semi-braking state by appropriately adjusting the operating pressure of the variable relief valve 38 by operating the steering lever 41 beyond the operating positions L1 and R1. According to this, the crawler traveling device 1 on the inner side of the turning is not completely fixed, and can be dragged while providing an appropriate resistance, which is more than the case where one crawler traveling device 1 is completely fixed. It is also possible to make a slightly looser one-brake turn.

[Another Embodiment] In the above embodiment,
Although the case where the side clutch gear 22 in the crawler traveling device is used for a structure in which a shift operation is directly performed by hydraulic pressure is illustrated, the invention may be used for a general traveling speed shift gear operation structure. In this case, in order to shift the shift gear in the normal and reverse directions, one shift is performed by a spring and the other shift is performed by supplying hydraulic oil to the oil chamber, similarly to the above-described embodiment. It is also possible to provide an oil chamber for normal operation and an oil chamber for reverse operation between the externally fitted support shaft, and to provide a structure for selectively supplying pressure oil to both oil chambers.

[Brief description of the drawings]

FIG. 1 is an overall side view of a combine.

FIG. 2 is a schematic view showing a transmission structure for traveling.

FIG. 3 is a hydraulic circuit diagram for aircraft steering.

FIG. 4 is a longitudinal sectional front view in which main parts are enlarged.

[Explanation of symbols]

 15 Central gear 21 Support shaft 22 Gear (side clutch gear) 24 Oil chamber 25 Oil passage

Claims (4)

[Claims] An oil chamber is formed between a spindle and a gear externally fitted to the spindle so as to be shiftable, and pressure oil supplied to the oil chamber via an oil passage formed in the spindle is provided. A gear transmission structure of a traveling transmission configured to shift the gear. 2. The gear transmission structure according to claim 1, wherein the gear and the support shaft are directly slidably fitted without interposing a seal ring. 3. A tolerance of a sliding portion between said gear and said support shaft is set so that a minute gap through which a part of pressure oil supplied to said oil chamber can flow out is formed. A gear transmission structure for the traveling transmission according to any one of the preceding claims. 4. The gear is externally shiftably fitted to a spindle of a central gear driven to change gears, and is engaged or disengaged from a side of the central gear, so that the power of the central gear is transferred to left and right crawlers. The gear transmission structure for a traveling transmission according to any one of claims 1 to 3, wherein the right and left side clutch gears are transmitted or disconnected to an axle for driving the traveling device.