JPH0723345Y2 - Hydraulic circuit in crawler lifting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a hydraulic circuit in a crawler lifting device.

<Prior art> Conventionally, for example, in a combine or the like, in order to achieve uniform traveling stability and cutting height in slope traveling and wetland traveling,
A crawler traveling device having an elevating mechanism that raises and lowers a wheel frame of the crawler traveling device to adjust the lateral height of the machine body has been considered.

The mechanism is generally composed of a lifting link mechanism connected to a roller frame and a lifting cylinder for driving the lifting link, as in the device disclosed in Japanese Utility Model Laid-Open No. 58-180775. The idler is supported by an idler cylinder that moves forward and backward according to the tension and slack of the crawler belt as it moves up and down.

Then, as described in the above publication, the lifting cylinder and the idler cylinder are operated by the switching valves provided separately,
It was necessary to separately move the idler cylinder forward and backward as well as lift the aircraft.

<Problems to be solved by the invention> However, in the above-mentioned conventional example, there is a problem that the timing of operating the idler cylinder is difficult due to the lifting and lowering of the machine body by the lifting cylinder, and the crawler belt comes off if the operation is mistaken during running. there were.

In addition, when each cylinder is extended, the sealing performance is not sufficient only when the switching valve is closed, and the oil gradually flows backward in the circuit and the cylinder retracts, causing the height of the machine body to decrease.
There was a drawback that the tension of the crawler belt was reduced.

<Means for Solving the Problems>
A lift cylinder that lifts and lowers the wheel frame 25 that supports 1 ...
19 is provided between the roller frame 25 and the main body, and the roller frame 25
In the crawler traveling device 1 provided with an idler cylinder 47 for supporting the idler 43 at the rear end thereof, the hydraulic circuit 61 for driving the lifting cylinder 19 and the idler cylinder 47.
The hydraulic circuit 62 for driving the three-position four-connection directional control valve 63 for switching the hydraulic pressure for both hydraulic circuits 61, 62 in an antithetical manner.
The switching valve 63 and each cylinder in each circuit 61, 62,
Pilot check valves 64 and 65 for preventing backflow from the cylinders 19 and 47 are provided between the cylinders 47 and 47, and the pilot circuits of the pilot check valves 64 and 65 are arranged in the other circuits 62 and 61.
Hydraulic circuit 62 that connects to and drives the idler cylinder 47.
Is provided with a throttle 67 in which a check valve 66 is connected in parallel, and the check valve 66 is provided in the same direction as the pilot check valve 65.

<Operation> In the lifting device provided in the crawler traveling device 1, the rolling wheel frame 25 is lowered with respect to the main body by the extension of the lifting cylinder 19, and the rolling wheel frame 25 is raised by the contraction of the lifting cylinder 19. The roller frame 25 is the roller 30, 31, 32
There is always a grounding position via the ..., The main body descends and rises by the ascending / descending operation of the roller frame 25.

The idler 43 is retreated by the idler cylinder 47 according to the forward / backward movement of the lifting cylinder 19. The hydraulic circuits 61 and 62 for driving the lifting cylinder 19 and the idler cylinder 47 are switched in the direction of hydraulic pressure by a switching valve 63 to which the hydraulic circuits 61 and 62 are connected. Further, the hydraulic circuits 61 and 62 are provided with pilot check valves 64 and 65 to prevent backflow from the cylinders 19 and 47. When hydraulic pressure is applied to one circuit 61, the pilot circuit opens the pilot check valve 65 of the other circuit, and oil is discharged from the cylinder 47.
Here, since the hydraulic circuit 62 is provided with the throttle 67 in which the check valve 66 is connected in parallel, resistance is generated in the backward movement of the idler cylinder 47, and when the idler cylinder 47 extends, the check valve 66 drives the idler cylinder 47 earlier than in the backward movement. Therefore, when the main body rises, the crawler belt 45 is gradually retracted to give tension to the crawler belt 45, and when the main body is lowered, the idler 43 is projected rearward faster than the slack of the crawler belt 45 is generated.

<Embodiment> An embodiment of the present invention will be described in detail below with reference to the drawings.

The crawler traveling device 1 shown in FIG. 2 is an embodiment of one used as a traveling device for a combine.

The machine body frame 4 assembled to mount a threshing device, a grain tank, and the like is composed of a vertical frame 2 and a horizontal frame 3. In the lower left and right of the body frame 4,
The crawler traveling device 1 is attached and the traveling body of the combine is moved.

Support frames 6 and 7 extending downward are provided at the left and right ends of a horizontal frame 3 horizontally provided in the left and right direction of the machine body frame 4, and the lower ends of the support frames 6 and 7 curved to the left and right are
The link mounting frame 9 is fixed in the front-rear direction.

FIG. 2 is an overall side view of the crawler traveling device 1. Links 13 and 14 are provided on the front and rear of the link mounting frame 9, respectively.
Are rotatably supported by rotating shafts 11 and 12. As shown in FIGS. 3 and 4, the rotating shafts 11 and 12 are inserted through the link mounting frame 9 so as to be rotatable in the left-right direction, and the link arms 15, 16, 17, and 18 are provided at both ends with the rotating shafts. It is fixed at a right angle to 11,12.

One end of a lifting cylinder 19 is connected to the upper end of the main body side link arm 15 of the front side link 13. The other end of the lifting cylinder 19 is swingably attached to the vertical frame 2 attached along the lower side of the machine body frame 4 by an attachment pin 19a.

A cylinder cover 20 is provided on the outside of the lifting cylinder 19 to prevent the cylinder cover 20 from rusting or being damaged due to muddy water fogging or an external impact. Further, unlike the conventional case, since the lifting cylinder 19 is attached to the outside of the machine body frame 4, the lifting cylinder 19 can be repaired and attached very easily.

Link arms 15, 17 of front link 13 and rear link 14
A connecting rod 21 is installed between them. Connecting rod 21
Is connected to each link arm 15 and 17 via a connecting pin 22 so as to be swingable by bosses 21a provided at both ends. The swing of the link 13 is transmitted to the link 14 by the connecting rod 21, and the same swing amount is obtained at the same time. Further, in the structure of this embodiment, since the lifting cylinder 19 is provided substantially horizontally and is substantially parallel to the connecting rod 21, the driving force of the lifting cylinder 19 is efficient and the rear link 14 is provided.
Be transmitted to.

Link arms 16 and 18 are fixed to the outer ends of the rotary shafts 11 and 12, and connection pins 23 and 24 are fixed to the ends of the link arms 16 and 24 in a penetrating manner. The connection pins 23, 24 are inserted into bosses 27, 28 fixed on the roller frame 25. The link arms 16 and 18 are swingably connected to the wheel frame 25 by the connection pins 23 and 24. Further, in order to avoid contact with the rolling wheels 35, 38 supported between the rotating shaft 11 and the connecting pin 23 and between the rotating shaft 12 and the connecting pin 24, the link arms 16, 18 are curved in a chevron shape. ing.
Therefore, the range in which the link arms 16 and 18 can swing without coming into contact with the rolling wheels 35 and 38 is widened, and the amount of vertical movement of the rolling frame 25 can be increased.

A reinforcing plate 29 is provided between the bosses 27 and 28 so as to sandwich the wheel frame 25 from the left and right. Rolling wheels 30 and 31 that are rotatably fixed and supported are provided at the front and rear ends of the rolling wheel frame 25, and between the rolling wheels 30 and 31, a fixed rotating rolling wheel 32 and rocking rolling wheels 35 and 36 are provided. , 37,38 are provided. Rolling wheels 35, 36, 37, 38 are pivotally supported at both ends of swinging members 33, 34 that are swingably supported at a predetermined distance on the rolling wheel frame 25, and rotate while moving up and down according to the unevenness of the road surface. To do.

A drive wheel 41 is supported in front of the link mounting frame 9,
An idler 43 is supported at the rear end of the wheel frame 25, and a crawler belt 45 is wound around the drive wheel 41, the idler 43, and the wheel wheels 30, 31, 32, 35, 36, 37, 38. .

Next, the support structure of the idler 43 will be described. As shown in FIGS. 5 to 7, an idler cylinder 47 is fixed rearward at the rear end of the roller frame 25. A mounting member is attached to the tip of the cylinder rod 48 of the idler cylinder 47.
53 is connected. Guide pipes 51 and 52 are fixed to both sides of the idler cylinder 47, and guide rods 49 and 50 are slidably inserted therein. A mounting member 53 is also fitted to the tips of the guide rods 49, 50. The mounting member 53 has a U-shape in a plan view, and has fitting portions 55 and 56 fitted to the guide rods 49 and 50, and a connecting portion 54 formed between the fitting portions 55 and 56. It consists of A U-shaped connecting member is fixed to the connecting portion 54 and is pin-joined to the cylinder rod 48 described above.

Then, the support shaft 57 is inserted between the fitting portions 55 and 56,
The idler 43 described above is rotatably supported on the support shaft 57. The peripheral end portion of the idler 43 enters a groove provided at the center of the crawler belt 45 and guides the crawler belt 45.

The idler 43 slides according to the looseness of the crawler belt 45 by the idler cylinder 47, but since the two guide rods 49, 50 bear the load applied to the idler 43 in the vertical and horizontal directions, the idler cylinder 47 is not added. Only the load in the front-rear direction is reduced, and the damage or failure of the idler cylinder 47 is reduced. Moreover, the support strength of the idler 43 is improved, and the straightness of the cylinder rod 48 is improved by being guided by the guide rods 49, 50 and the guide pipes 51, 52.
The front and rear slides of will also be smooth.

FIG. 8 is an enlarged front sectional view showing the support structure of the upper wheel 58. The upper roller 58, which is transferred from the lower side to the non-grounded portion of the crawler belt 45, is supported by a shaft 60 that passes through a support pipe 59 fixed on the link mounting frame 9.
Then, the shaft 60 is rotatably supported by the shaft 60 and constantly rolls inside the crawler belt 45.

FIG. 1 shows a hydraulic circuit of the combine, and a drive circuit for the lifting cylinder 19 and the idler cylinder 47 will be described with reference to this drawing. Hydraulic circuits 61 and 62 are connected to the lifting cylinder 19 and the idler cylinder 47, respectively.
Each hydraulic circuit 61, 62 is connected to the switching valve 63. Switching valve 6
Reference numeral 3 is a three-position four-way valve, which is electrically switched so that oil flows in the hydraulic circuits 61 and 62 in opposite directions. Pilot check valves 64, 65 are provided in the hydraulic circuits 61, 62 between the switching valve 63 and the cylinders 19, 47 to prevent backflow from the cylinders 19, 47. In addition, each pilot check valve
The pilot circuits of 64 and 65 are mutually connected to the hydraulic circuits 62 and 61 of the other side, and when hydraulic pressure toward the cylinder is applied to one circuit, the check valve of the other circuit moves in the direction in which oil flows from the cylinder. It is supposed to open.

In the hydraulic circuit 62 connected to the idler cylinder 47,
A throttle 67 having a check valve 66 connected in parallel is provided between the idler cylinder 47 and the pilot check valve 65.
The check valve 66 is provided in the same direction as the pilot check valve 65. Further, the hydraulic circuit 62 is connected to the drain circuit via the cock 68, and by opening the cock 68, the hydraulic pressure of the idler cylinder 47 can be easily released.

Similarly, the hydraulic circuit 62 of the idler cylinder 47 is provided with a relief valve 69. According to this relief valve 69, even if stones or mud are caught between the crawler belt 45 and the idler 43, and the tension of the crawler belt 45 is applied more than necessary, if the pressure of the idler cylinder 47 reaches a certain value or more, The relief valve 69 opens and the idler cylinder 47 is contracted. In other words, the structure is such that the idler 43 is retracted when an excessive tension is applied to the crawler belt 45.
Less damage to the crawler belt 45.

Further, to the hydraulic circuit 62, a pretreatment drive hydraulic circuit 72 for operating and driving the pretreatment cylinder 71 is connected via a check valve 70. The check valve 70 is set so that oil flows from the pretreatment drive hydraulic circuit 72 toward the hydraulic circuit 62. With this configuration, every time the pretreatment unit is moved up and down by the pretreatment cylinder 71, hydraulic pressure is applied to the idler cylinder 47, and the idler 43 projects in a direction in which tension is applied to the crawler belt 45. Therefore, the crawler belt
45 has a structure in which a constant tension is always maintained by raising and lowering the pretreatment section.

The drive hydraulic circuits for the lifting cylinder 19 and the idler cylinder 47 described above are provided separately for the left and right crawler traveling devices 1. Further, since the hydraulic circuit is provided with the pilot check valves 64 and 65, the cylinder leakage is small, and the machine body height and the idler 43 position are stable. Further, since the two switching cylinders 63 operate the two cylinders 19 and 43, the operability is good and the structure is simple.

Hereinafter, the operation of the structure of this embodiment will be described based on the above configuration. As shown in FIG. 2, when the lifting cylinder 19 is contracted, the roller frame 25 is closest to the link mounting frame 9, and the height of the machine body is at the lowest position. The upper roller 58 is in rolling contact with the crawler belt 45.

Here, when the switching valve 63 is switched to apply hydraulic pressure to the lifting cylinder 19, the lifting cylinder 19 is extended by the hydraulic pressure, the link arm 15 swings, and at the same time, the link rod 17 on the rear side swings by the connecting rod 21. Due to the swinging of the links 13 and 14, the roller frame 25 descends horizontally with respect to the machine body, and also moves slightly rearward along the rotation trajectory of the tips of the link arms 16 and 18.

Since the drive wheels 41 and the upper wheels 58 are fixed to the machine body frame 4, the crawler belt 45 extends and deforms in the vertical direction as the wheel frame 25 descends, and the length in the front-rear direction is the rear end portion. Retracts and shortens. The idler 43 that supports the rear end of the crawler belt 45 from the inside is
Is pushed forward by the deformation of, and pressure is applied to the idler cylinder 47 in a contracting (retracting) direction.

In the hydraulic circuit 62 of the idler cylinder 47, the lifting cylinder 19
The hydraulic pressure to opens the pilot check valve 65, and oil flows in the discharge direction. Here, since the hydraulic circuit 62 is provided with the throttle 67, a certain resistance is generated when the idler cylinder 47 is retracted. For this reason, when the crawler belt 45 is tensioned by more than the retracting resistance generated in the idler cylinder 47, the idler 43 is retracted, and when the roller frame 25 is lowered, the crawler belt 45 is always kept constant. Tension is maintained.

On the other hand, the wheel frame 25 moves rearward and downward with respect to the drive wheels 41 due to the swinging of the links 13 and 14, so the front elevation angle with respect to the ground contact surface of the crawler traveling device 1 does not change much. In addition, the rollers 30,3 that determine the ground contact length of the crawler belt 45
The distance between 1,32,35,36,37,38 does not change, and therefore the ground contact length of the crawler belt 45 does not change. In addition, the roller frame 25
The height of the machine becomes higher due to the lowering of the machine, and it becomes more unstable than when the machine is low.However, the roller frame 25 moves backward and the ground contact portion of the crawler belt 45 moves toward the center of gravity, and the crawler belt Since the contact length of the 45 is constant, the stability of the aircraft is relieved.

When lowering the machine body, the switching valve 63 is switched to apply hydraulic pressure to the hydraulic circuit 62. The pilot check valve 64 is opened by the hydraulic pressure of the hydraulic circuit 62, the lift cylinder 19 contracts (retracts) due to the weight of the machine body, and oil flows in the discharge direction,
The lift cylinder 19 is provided by a throttle provided in the hydraulic circuit 61.
The retreat is gradually performed. The hydraulic pressure applied to the hydraulic circuit 62 reaches the idler cylinder 47, but since the throttle valve 67 and the check valve 66 are connected in parallel, the lifting cylinder 19
Oil is transmitted faster than.

Due to the contraction of the lifting cylinder 19, the wheel frame 25 gradually approaches the machine body, and the machine body slowly descends. Here, although the crawler belt 45 is loosened, as described above, since the idler cylinder 47 expands quickly, the idler 43 projects rearward and pulls the crawler belt 45 before the crawler belt 45 loosens. Therefore, even if the roller frame 25 rises with respect to the aircraft, the crawler belt
The tension of 45 does not decrease.

That is, the tension of the crawler belt 45 is not lost even when the roller frame 25 is moved up and down, and the trouble that the crawler belt 45 comes off when the roller frame 25 is moved up and down is reduced.

If you open the cock 68 to release the pressure of the idler cylinder 47 and retract the idler 43, you can easily move the crawler belt.
45 can be attached and detached, and the lifting cylinder 19 can be easily repaired.

As shown in FIG. 2, the upper roller 58 is always in rolling contact with the crawler belt 45 regardless of the shape of the crawler belt 45 as the roller frame 25 moves up and down. Therefore, there is no situation where the upper roller 58 does not come into contact with the crawler belt 45 when the roller frame 25 is close to the machine body frame 4, and there is no problem that the upper roller 58 becomes sluggish in rotation and wears down.

<Effect of Device> According to the circuit of the present invention configured as described above, 3 positions 4
Since the connection direction switching valve is provided, the forward / backward movement of the lift cylinder and the forward / backward movement of the idler cylinder can be simultaneously performed by a single switching operation. For this reason, there is an effect that the operation becomes simple and the ascending / descending operation and the horizontal maintaining operation of the main body are performed very efficiently.

Further, the throttle provided in the hydraulic circuit causes the idler to move forward and backward so that the crawler belt is always tensioned, which has the advantage of reducing the trouble of the crawler belt coming loose when the roller frame is moved up and down.

Furthermore, by providing a pilot check valve,
The backflow from each cylinder can be stopped without applying a load to the 3-position 4-connection directional control valve. Further, it is possible to reliably prevent the lowering of the machine body and the backward movement of the idler due to the reverse flow from the cylinder.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of the combine of this embodiment, FIG. 2 is an overall side view of the crawler traveling device, FIG. 3 is a front sectional view of the left and right crawler traveling devices, and FIG. Sectional view, FIG. 5 is a plan sectional view showing the mounting state of the idler and the idler cylinder, FIG. 6 is a side view of the same,
FIG. 7 is a front view of the same, and FIG. 8 is a front sectional view showing a mounting state of the upper roller. 1: Crawler traveling device, 19: Lifting cylinder 25: Rolling wheel frame, 30, 31, 32 …… Rolling wheel 43: Idler, 47: Idler cylinder 61: Hydraulic circuit, 62: Hydraulic circuit 63: Switching valve, 64, 65 : Pilot check valve 66: Check valve, 67: Throttle

Claims (1)

[Scope of utility model registration request] 1. A roll wheel frame (25) for supporting roll wheels (30, 31 ...) Is freely movable up and down with respect to a main body, and a lift cylinder (19) for driving the roll wheel frame (25) up and down is mounted on the roll wheel. In a crawler traveling device (1) provided between a frame (25) and a main body, and provided with an idler cylinder (47) for supporting an idler (43) at a rear end of a roller frame (25), an elevating cylinder. The hydraulic circuit (61) for driving (19) and the hydraulic circuit (62) for driving the idler cylinder (47) have a three-position, four-connection direction in which the hydraulic pressure for both hydraulic circuits (61), (62) is switched in a contradictory manner. A switching valve (63) is connected, and each cylinder (19), (47) is connected between the switching valve (63) and each cylinder (19), (47) in each circuit (61), (62). Check valves (64), (6
5) is provided for each pilot check valve (64), (65)
Throttle circuit (67) with a check valve (66) connected in parallel to the hydraulic circuit (62) that drives the idler cylinder (47) by connecting the pilot circuits of the other to the other circuits (62) and (61).
The check valve (66) is a hydraulic circuit in the crawler lifting device provided in the same direction as the pilot check valve (65).