JPH089342B2 - Traveling equipment for work vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a traveling device for a working vehicle such as an asphalt finisher traveling with a traveling hydraulic motor.

[Prior Art] Generally, a work vehicle is required to have a traveling function and a working function, and many of them use a hydraulic circuit as a traveling device for driving a rotational driving body such as a crawler.

For example, in a work vehicle such as an asphalt finisher, a traveling device for driving left and right crawlers by using two independent hydraulic motors for traveling is known as shown in Japanese Utility Model Laid-Open No. 63-171412.

FIG. 2 shows an example of a traveling device of this type of asphalt finisher.

In the figure, reference numeral 101 denotes an engine, and an output shaft 101A of the engine 101 is provided with a traveling hydraulic pump 102 for the right side and a traveling hydraulic pump 103 for the left side. The traveling hydraulic pumps 102, 103 are of variable displacement type.

The right-side traveling hydraulic pump 102 is connected to a right-side traveling hydraulic motor 105 via a pipe 104, and the left-side traveling hydraulic pump 103 is connected to a left-side traveling hydraulic motor 107 via a pipe 106. Connected to. Hydraulic motor for traveling 1 for the right side
The crawler 108 on the right side is driven by 05, and the crawler 109 on the left side is driven by the traveling hydraulic motor 107 for the left side.

Therefore, when the asphalt finisher is going straight, the discharge amounts of the traveling hydraulic pumps 102, 103 are made the same, and the rotational speeds of the traveling hydraulic motors 105, 107 are made the same.

When the asphalt finisher turns, a differential function is generated by setting a difference in the discharge amount of the traveling hydraulic pumps 102, 103 and providing a difference in the rotational speeds of the traveling hydraulic motors 105, 107 to drive the crawlers 108, 109. ing.

[Problems to be Solved by the Invention]

However, in the conventional traveling device for an asphalt finisher, the two traveling hydraulic pumps 102, 103 and the two traveling hydraulic motors 105, 107 operated by the hydraulic pumps 102, 103 are used to drive the left and right crawlers 108, 109. That is, the 2-pump-2 motor system is adopted.

Therefore, when the asphalt / finisher is going straight, the discharge amounts of the traveling hydraulic pumps 102, 103 are controlled to be the same, but due to the difference in the traveling loads of the left and right crawlers 108, 109, and the traveling hydraulic pumps 102. ,Ten
Since the efficiency of 3 etc. is different and the capacity per unit rotation of the traveling hydraulic motors 105, 107 is different, the rotational speed of the traveling hydraulic motors 105, 107 is also different, so that the straightness of the asphalt finisher is improved. There was a problem that it was difficult to secure and there was a risk of meandering.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a traveling device for a work vehicle capable of improving straightness of a work vehicle such as an asphalt finisher. is there.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a traveling hydraulic pump that is operated by the rotational driving force of an engine, and a traveling hydraulic motor that is operated by oil supplied from the traveling hydraulic pump,
In a traveling device for a working vehicle, which is provided with a rotary driving body such as left and right crawlers driven by a traveling hydraulic motor, a variable displacement swing hydraulic pump that is operated by the rotational driving force of an engine and a swing hydraulic pump are used. It has a turning hydraulic motor that operates, and a pair of planetary gear mechanisms that connect each sun gear via a drive input shaft that is rotated by the rotational driving force of the traveling hydraulic motor, and the planetary gears of the planetary gear mechanism rotate left and right. The ring gears of the pair of planetary gear mechanisms, which are respectively connected to opposite one ends of the drive shafts of the body, are configured to be rotatable / stoppable so that a difference in rotational speed between both planetary gears occurs when at least one of them rotates. ,
Each ring gear is connected to a turning hydraulic motor via a transmission means, a traveling hydraulic pump and a turning hydraulic pump are provided on the output shaft of the engine, and a drive path from the output shaft of the turning hydraulic motor to the planetary gear mechanism is provided. A straight braking device for holding the output shaft of the turning hydraulic motor in a fixed state during straight traveling is provided.

[Work]

According to the present invention, when the work vehicle travels straight, the turning hydraulic motor is stopped and the ring gears of the pair of planetary gear mechanisms are stopped and held in a fixed state by operating the brake device. Therefore, both planetary gear mechanisms are not affected by the rotation of the ring gears, and the rotation speeds of both planetary gears are proportional to the rotation speeds of both sun gears.

However, in the traveling hydraulic motor, the sun gears of both planetary gear mechanisms rotate simultaneously at the same speed.

Therefore, the planetary gears of both planetary gear mechanisms rotate at the same rotational speed, and the drive shafts connected to the planetary gears also rotate at the same rotational speed.

When the vehicle travels straight, the output shaft of the turning motor is held in a fixed state by operating the straight braking device.
Even if there is a difference between the left and right running loads, the rotational force due to the difference between the left and right running loads from the rotary drive and the planetary gear mechanism is received by the output shaft of the turning motor and does not reach the turning hydraulic motor.

On the other hand, when the work vehicle turns, the brake device releases the fixed state of at least one of the ring gears of both planetary gear mechanisms, and operates the turning hydraulic motor. As a result, the ring gear of the planetary gear mechanism, which receives the rotational driving force from the turning hydraulic motor via the transmission means, rotates so that the rotational speeds of both planetary gears differ.

Then, the rotation speed of the planetary gears of both planetary gear mechanisms is obtained by adding the rotation speed (including the direction) of each ring gear to the rotation speed of the sun gear. That is, the two planetary gear mechanisms function as a differential gear mechanism.

Therefore, the planetary gears of the two planetary gear mechanisms rotate at different rotational speeds, which causes a difference in the rotational speeds of the drive shafts of the left and right rotary drive bodies connected to the planetary gears.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a traveling device for a working vehicle according to an embodiment of the present invention, and a case where the traveling device is applied to an asphalt finisher as a working vehicle will be described.

In the figure, reference numeral 1 denotes an engine mounted on an asphalt finisher K, and an output shaft 1A of the engine 1 is provided with a variable displacement type traveling hydraulic pump 2 and a variable displacement type turning hydraulic pump 3.

The traveling hydraulic pump 2 is connected to a traveling hydraulic motor 5 via a pipe 4, and the turning hydraulic pump 3 is connected to a turning hydraulic motor 7 via a pipe 6.

Reference numeral 8 denotes a planetary gear mechanism on the right side, which is composed of a sun gear 9, three planetary gears 10, 10, 10 and a ring gear 11. The ring gear 11 is configured to rotate and stop freely,
An outer peripheral gear 11A is formed on the outer periphery. The planetary gear 10 is connected to one end of a drive shaft 13 via a link member 12, and the drive shaft 13 has a coupling 13A.
A sprocket 14 is fixed to the other end of the sprocket 14, and the sprocket 14 is connected to a sprocket 16 via a chain 15, and the sprocket 16 is connected to a drive transmission portion 17A of a rotary drive body including a crawler 17.

Reference numeral 18 denotes a planetary gear mechanism on the left side, which includes a sun gear 19, three planetary gears 20, 20, 20 and a ring gear 21. The ring gear 21 is configured to rotate and stop freely,
An outer peripheral gear 21A is formed on the outer peripheral surface thereof. The planetary gear 20 is connected to one end of a drive shaft 23 via a link member 22, the drive shaft 23 has a coupling 23A, and the sprocket 24 is fixed to the other end of the drive shaft 23, and the sprocket 24 is a chain. It is connected to a sprocket 26 via 25, and this sprocket 26 is connected to a drive transmission portion 27A of a rotation drive body composed of a crawler 27.

The sun gears 9 and 19 of the two planetary gear mechanisms 8 and 18 are connected to both ends of the drive input shaft 28, and the first gear 28A provided in the middle of the drive input shaft 28 travels via the second gear 29. It is connected to a third gear 5B provided in the middle of the output shaft 5A of the hydraulic motor 5 for use. A parking brake device 30 is attached to the tip of the output shaft 5A of the traveling hydraulic motor 5.

Further, the output shaft 7A of the turning hydraulic motor 7 is provided with a fourth gear 7B in the middle of the output shaft 7A, and a linear braking device 31 is attached to the tip thereof. Fourth gear 7B is a support shaft
The support shaft 32 meshes with the fifth gear 32A fixed to one end of 32.
A sixth gear 32B is fixed in the middle of the shaft, and a seventh gear 33 is fixed to the other end. The seventh gear 33 meshes with the outer peripheral gear 21A of the ring gear 21.

The sixth gear 32B is an eighth gear 34A fixed to one end of the support shaft 34.
The ninth gear 34B, which is meshed with and fixed to the other end of the support shaft 34, meshes with the outer peripheral gear 11A of the ring gear 11 of the right planetary gear mechanism 8. The number of teeth of the fifth gear 32A and the sixth gear 3
The number of teeth of 2B is the same, and the number of teeth of the 7th gear 33 and that of the 9th gear
34B has the same number of teeth, and the output shaft 7 of the turning hydraulic motor 7
When A rotates, the rotation is transmitted to the ring gears 11 and 21 via the gear train described above as described later, and the ring gears 11 and 21
21 are designed to rotate the same amount in opposite directions.

 Next, the operation of this embodiment will be described.

First, the case where the asphalt / fnisher K goes straight will be described. The discharge amount of the turning hydraulic pump 3 is controlled to zero to stop the turning hydraulic motor 7, and the straight advance brake device 31 is operated to output the output shaft 7A of the turning motor 7.
By holding the two in a fixed state, both planetary gear mechanisms 8,18
The ring gears 11 and 21 are stopped and held in a fixed state.
Therefore, the two planetary gear mechanisms 8 and 18 are not affected by the rotation of the ring gears 11 and 21, and the rotation speeds of the planetary gears 10 and 20 are proportional to the rotation speeds of the sun gears 9 and 19, respectively.

Here, by operating the traveling hydraulic pump 2, the traveling hydraulic motor 5 operates. The rotational driving force of the traveling hydraulic motor 5 is generated by the output shaft 5A of the traveling hydraulic motor 5 → the third gear 5B → the second gear 29 → the first gear 28A → the drive input shaft 28 →
The sun gears 9 and 19 are transmitted in this order to the sun gears 9 and 19, and the traveling hydraulic motor 5 causes the sun gears 9 and 19 of both planetary gear mechanisms 8 and 18 to rotate simultaneously at the same rotational speed.

Therefore, the planetary gears 10,20 of both planetary gear mechanisms 8,18 are
Rotate at the same speed, and planetary gears 10, 20
Both drive shafts 13 and 23 connected to are also rotated at the same rotational speed. As a result, both crawlers 17 and 27 are driven at the same rotation speed and go straight.

Next, a case where the asphalt / fnisher K turns will be described. As a premise, the traveling hydraulic pump 2 is operated to drive the traveling hydraulic motor 5. Therefore,
As in the case of going straight, the sun gears 9 and 19 of 8 and 18 of both planetary gear mechanisms are rotating at the same rotation speed.

First, the straight braking device 31 is operated to allow the output shaft 7A of the turning hydraulic motor 7 to rotate freely, and the turning hydraulic pump 3 is operated to operate the turning hydraulic motor 7. As a result, the rotational driving force of the turning hydraulic motor 7 is
The output shaft 7A → the fourth gear 7B → the fifth gear 32A → the sixth gear 32B → the eighth gear 34A → the ninth gear 34B → the outer peripheral gear 11A of the right ring gear 11 are transmitted to the ring gear 11 in this order. As a result, the entire ring gear 11 rotates in a certain direction by a predetermined amount, and accordingly, the planetary gear 10 rotates in the same direction by a predetermined amount.

At the same time, the rotational driving force of the turning hydraulic motor 7 is
7A → the fourth gear 7B → the fifth gear 32A → the seventh gear 33 → the outer peripheral gear 21A of the left ring gear 21 is transmitted to the ring gear 21 in this order. As a result, the entire ring gear 21
The planetary gear 20 rotates in the same direction in the opposite direction to that of the above, and accordingly, the planetary gear 20 rotates in the same direction by a predetermined amount.

That is, the left and right planetary gears 10, 2 are rotated by rotating the left and right ring gears 11, 21 in opposite directions by the same amount.
0 rotates the same amount in opposite directions.

Then, the rotational speeds (including the directions) of the left and right ring gears 11 and 21 described above are added to the rotational speeds of the sun gears 9 and 19, and the different rotational speeds of the planetary gears 10 and 20 of the planetary gear mechanisms 8 and 18 are changed. can get. That is, both planetary gear mechanisms 8 and 18 function as a differential gear mechanism.

In this way, the planetary gears 10 and 20 of both planetary gear mechanisms 8 and 18 rotate at different rotational speeds, and the planetary gears 1 and 20 rotate.
The left and right crawlers 17 and 27 connected to 0 and 20 are driven at different rotational speeds, and the asphalt finisher K turns smoothly according to the traveling load.

Further, by changing the rotation direction of the turning hydraulic motor 7, it is possible to change the rotation directions of the ring gears 11 and 21 to respond to the left and right turning of the asphalt finisher K.

According to the above configuration, one traveling hydraulic motor 5
Since the rotation of is mechanically transmitted to the drive shafts 13 and 23 of the left and right crawlers 17 and 27 through the left and right planetary gear mechanisms 8 and 18, even if there is a difference in running load acting on the crawlers 17 and 27, Further, unlike the conventional example, since two traveling hydraulic motors are not used, there is no room for a difference in the number of revolutions of the respective traveling hydraulic motors in that case, and the crawlers 17 and 27 rotate at the same speed when traveling straight. It can be rotated by a number to ensure straightness.

More specifically, when the asphalt / finisher K travels straight, even if there is a difference in the left and right traveling loads, the output shaft of the turning motor 7 can be operated by operating the straight braking device 31.
7A is held in a fixed state, and the rotational force due to the difference between the left and right running loads from the rotation driving body composed of crawlers 17 and 27 and the planetary gear mechanisms 8 and 18 is received by the output shaft 7A of the turning motor 7 and used for turning. It does not reach the hydraulic motor 7. Therefore, the straightness of the asphalt finisher K can be secured.

Of course, it is required to ensure the straightness and the turning function of the asphalt finisher K, but at the time of turning, the planetary gears 10,20 of the left and right planetary gear mechanisms 8,18 are required.
Difference between the output speeds of the left and right crawler
Since it is possible to provide a difference in the number of revolutions to 17,27, the asphalt finisher K can be smoothly turned.

In this embodiment, the left and right ring gears 11, 21
Although the planetary gears 10 and 20 are rotated by the same amount in opposite directions to each other, the rotational speed difference is generated in the planetary gears 10 and 20, but in the turning hydraulic motor 7, the ring gears 11 and 21 are transmitted via transmission means such as gears and chains. By rotating the ring gears 11 and 21 in the same direction and causing a difference in the number of rotations, the difference in the number of rotations in the same direction between the left and right ring gears 11 and 21 is set. , 20
It is also possible to generate a difference in the number of rotations in the two planetary gear mechanisms 8 and 18 so as to have a differential function.

Also in this embodiment, the left and right ring gears 11, 21
Although the planetary gears 10 and 20 are rotated by the same amount in opposite directions to each other, the planetary gears 10 and 20 are rotated by the same amount.However, by stopping only one of the left and right ring gears 11 and 21 and rotating the other, the planetary gears are rotated. 10,20
It is also possible to generate a rotational speed difference. In this case, a clutch mechanism must be provided in the middle of the drive path from the turning motor 7 to the ring gears 11 and 21 so that the rotational drive force is not transmitted to only one of the left and right ring gears 11 and 21.

Further, in the present embodiment, the straight traveling brake device 31 is provided at the tip of the output shaft 7A of the turning motor 7, but the straight traveling brake device 31 drives the output shaft 7A to the ring gears 11 and 21. It can also be provided in the path (including the ring gears 11 and 21).

Further, in the present embodiment, the crawlers 17 and 27 are described as an example of the rotary driving body, but the present invention is not limited to this and can be applied to wheels as the rotary driving body.

Further, in the present embodiment, the case where the work vehicle is applied to the asphalt finisher K has been described, but the present invention is not limited to this and can be applied to, for example, a mobile crane.

〔The invention's effect〕

As described above, according to the present invention, the rotation of one traveling hydraulic motor is mechanically transmitted to the drive shafts of the left and right rotary drive bodies via the left and right planetary gear mechanisms. Even if there is a difference in running load, or because the two running hydraulic motors are not used for the left and right rotary drives as in the conventional example, the rotational speed of each running hydraulic motor in that case is There is no room for the difference, and when driving straight ahead, the left and right rotary driving bodies rotate at the same number of rotations, so that straightness can be ensured.

More specifically, when the vehicle travels straight, even if there is a difference in the left and right traveling loads, the output shaft of the turning motor is held in a fixed state by operating the straight braking device, so that the rotation drive unit and the planetary gear mechanism are held. The rotational force due to the difference between the left and right running loads is received by the output shaft of the turning motor and does not reach the turning hydraulic motor. Therefore, the straightness of the working vehicle can be ensured.

Of course, it is required to secure the straightness and the turning function of the work vehicle, but at the time of turning, a rotation difference is generated in the output rotation speed of the planetary gears of the left and right planetary gear mechanisms to rotate the left and right rotary drive bodies. Since a difference in number can be provided, the work vehicle can smoothly turn.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional plan view of a traveling device for an asphalt finisher according to an embodiment of the present invention. FIG. 2 is a plan view of a conventional traveling device for an asphalt finisher. [Description of major parts] 1 …… Engine 2 …… Traveling hydraulic pump 3 …… Turning hydraulic pump 5 …… Travel hydraulic motor 7 …… Turning hydraulic motor 8,18 …… Planetary gear mechanism 9 , 19 ...... Sun gear 10,20 …… Planetary gear 11,21 …… Ring gear 13,23 …… Drive shaft 28 …… Drive input shaft 31 …… Brake device for straight drive.

Claims (1)

[Claims] 1. A traveling hydraulic pump operated by the rotational driving force of an engine, a traveling hydraulic motor operated by oil supplied from the traveling hydraulic pump, and rotation of left and right crawlers driven by the traveling hydraulic motor. In a traveling device for a working vehicle including a driving body, a variable displacement swing hydraulic pump that is operated by the rotational driving force of an engine, a swing hydraulic motor that is driven by the swing hydraulic pump, and a travel hydraulic motor. It has a pair of planetary gear mechanisms that connect each sun gear via a drive input shaft that is rotated by a rotational drive force, and the planetary gears of the planetary gear mechanism are connected to the opposite end sides of each drive shaft of the left and right rotary drive bodies, respectively. The ring gears of the pair of planetary gear mechanisms can be freely rotated and stopped so that the rotational speeds of both planetary gears differ when at least one of them rotates. Each of the ring gears is connected to the turning hydraulic motor via the transmission means, the traveling hydraulic pump and the turning hydraulic pump are provided on the output shaft of the engine, and the output shaft of the turning hydraulic motor reaches the planetary gear mechanism. A traveling device for a working vehicle, characterized in that a straight traveling brake device for holding an output shaft of a hydraulic motor for turning in a fixed state when traveling straight ahead is provided on a drive path.