KR102199770B1 - Auto leveling apparatus for tractor - Google Patents

Abstract

The present invention provides an apparatus for automatically leveling a vehicle body of a tractor, which includes buffer cylinders installed between the vehicle body and front and rear axles of the tractor, respectively, to buffer the lifted vehicle body. The apparatus for automatically leveling a vehicle body of a tractor includes: an unloading valve controlling a hydraulic pressure by a hydraulic pump so that the hydraulic pressure is supplied when the buffer cylinders are lifted; a lifting valve and a lowering valve provided between the unloading valve and each of the buffer cylinders to lift or lower each of the buffer cylinders; and a cushion fixing valve provided between the lifting and lowering valves and each of the buffer cylinders, respectively, to fix a cushion of each of the buffer cylinders.

Description

Automatic leveling apparatus for a tractor body TECHNICAL FIELD

The present invention relates to an automatic leveling device for a tractor body, and more particularly, the height of the tractor body when the vehicle body of the tractor is raised and lowered when the tractor is stopped and the tractor body is started for movement. It relates to an automatic leveling device for a tractor body that is automatically leveled and adjusted to the original position at the time of setting.

In general, a tractor is a work vehicle that performs various tasks in the field of agriculture or construction using a traction force.

In particular, agricultural tractors are used for transporting crops or mechanized farming, and such a tractor has a loader that can rotate up and down in front of it, while the front end of the loader is among the attachments, which are various work equipment such as bale tongs, buckets, and hooks. Either one is installed to perform the work, and at the rear of the tractor, any one of working machines such as a rotor for cultivation, a trailer for transporting crops, and a dozer for dozer work is installed to perform the work.

The power generated from the engine of such an agricultural tractor is divided into a odometer power that drives the wheels required for driving through a transmission and a power take off (PTO) power that drives various types of work machines mounted on the tractor. The general power of the system is a four-wheel drive system.

Such a tractor has a similar structure to a general car, but compared to a general car, it is equipped with a powerful engine and the working environment is poor, such as uneven ground or bumping into obstacles during work, but has a cushioning function to protect it. It is on the weak side.

Due to this, the driver is easily fatigued even in a short period of time, and the tractor itself has a disadvantage in that accessory equipment is easily damaged or the lifespan is shortened due to the work in a poor environment.

In order to solve these shortcomings, the present inventor has proposed "a tractor with a buffer function reinforced" in Korean Patent No. 10-1239786 (hereinafter referred to as'prior technical literature').

The tractor with a buffer function disclosed in the prior art document has an upper link and a lower link hinged up and down of the front axle for buffering the front axle of the tractor to have a pair of left and right four link structures. A shock absorber is installed on the left and right sides of the front axle, respectively, to have a shock absorber to relieve the upper and lower shocks of the front axle.The arm is fixed to the rear axle so that it does not move left and right, and has a structure that can flow up and down. By installing a pair of left and right, and installing buffer cylinders on the left and right sides of the rear axle, each has a shock absorber that alleviates the vertical impact of the rear axle, so that the front and rear axles of the tractor can be generated during work or movement. It is equipped with a shock absorber that can further alleviate the impact.

In particular, the conventional shock absorber disclosed in the prior art document has a structure in which the vehicle body is lowered due to a high load applied to the vehicle body when the tractor is stopped working, and the vehicle body is raised when the load acting on the vehicle body is small. Has been.

However, conventionally, even when the tractor is started and driven after the tractor is stopped, the height of the body of the tractor remains the same as the height of the stop operation. There is a problem that is passed on.

Domestic registered patent No. 10-1239786

Accordingly, the present invention has been devised to solve the problems of the prior art as described above, and when the tractor is stopped, the vehicle body of the tractor is fixed as it is in an elevated state and the tractor is started for movement. It is an object of the present invention to provide an automatic leveling device for a tractor body in which the tractor body is automatically leveled and returned to the original height at the time of setting when hung.

An automatic leveling device for a tractor body according to the present invention for achieving the above object is an automatic leveling device for a tractor body comprising a buffer cylinder that is installed between the body and the front and rear axles of the tractor and buffers the vehicle body to be elevated. The vehicle body automatic leveling device includes an unloading valve that controls hydraulic pressure by a hydraulic pump to be supplied when the buffer cylinder is raised; A rising valve and a falling valve provided between the unloading valve and each buffer cylinder to raise or lower each buffer cylinder; It may include; a cushion fixing valve provided between the rising valve and the falling valve and each buffer cylinder to fix the cushion of each buffer cylinder.

In addition, an orifice may be provided in the hydraulic line between the rising valve and the falling valve and each cushion fixing valve to alleviate a sudden descent of the vehicle body.

In addition, the front cushioning valve is equipped with each accumulator that buffers the front buffer cylinder, and the rear cushioning valve is equipped with a single accumulator that simultaneously buffers the rear buffer cylinder by connecting both cushioning valves. Can be.

In addition, each cushion fixing valve may be provided to stop the buffer function of the buffer cylinder by being locked during the stop operation of the tractor to block the connection between each buffer cylinder and the accumulator.

In addition, the left and right fixed valves are provided between the front two cushioning valves, preventing the tractor from overturning by fixing the hydraulic flow between the two buffer cylinders in the front when stopping or running at high speed. It may be provided to connect the hydraulic flow between the buffer cylinders.

According to the tractor body automatic leveling device of the present invention, the shock absorbing means of the tractor is fixed so that the vehicle body of the tractor is raised and lowered when the tractor is stopped, so that the shock absorbing operation is stopped, and the vehicle body of the tractor when the tractor is started. By automatically leveling and returning to the original height at the time of setting, the vehicle body maintains a fixed state for smooth work, and when driving, it has the advantage of absorbing shocks and buffering the road surface by buffering operation by a buffering means. have.

1 is an overall perspective view of a tractor body configured with an automatic leveling device according to the present invention.
2 is a hydraulic system diagram of the automatic leveling device according to the present invention, which is a hydraulic system diagram in a state in which the automatic leveling device is fixed when the tractor is stopped.
3 is a view showing a buffer cylinder according to the present invention, FIG. 3A is a separate configuration diagram of the buffer cylinder, and FIG. 3B is a view showing a fixed state of the buffer cylinder.
4 is a hydraulic system diagram in a state in which the automatic leveling device is released when the tractor according to the present invention is started.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Terms used in the present invention are terms defined in consideration of functions in the present invention, and since these may vary according to the intention or custom of users or operators, the definitions of these terms correspond to the technical matters of the present invention. And should be interpreted as a concept.

In addition, the embodiments of the present invention do not limit the scope of the present invention, but are merely exemplary matters of the elements presented in the claims of the present invention, and are included in the technical idea throughout the specification of the present invention. This is an embodiment including a component that can be substituted as an equivalent in the component.

In addition, optional terms in the following embodiments are used to distinguish one component from other components, and the component is not limited by the terms.

Accordingly, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 to 4 are views showing a hydraulic system diagram of a tractor vehicle body and an automatic leveling device configured therein according to the present invention.

The body 1 of the tractor according to the present invention includes a front axle 10 and a rear axle 20, as shown in FIG. 1, but the front axle 10 is subject to interference from the steered front wheels (not shown). It is formed by being bent upward so that the rear axle 20 is formed to have a relatively lower height than the front axle 10, and an engine (not shown) is located in the middle of the front axle 10 and the rear axle 20 It is formed in a recessed structure so that it can be disposed and provided, and a cab, that is, a cabin (not shown) is installed and provided above the engine.

The front and rear axles 10 and 20 are provided with a buffering function by a buffering means, and the front axle 10 provided with the front wheel to be steered has its one end hinged above and below the front axle 10. The upper link 11 and the lower link 12, which are coupled and hinged to the vehicle body 1, are installed in a pair on both left and right sides, and are provided in a four-fold link structure so that the front axle 10 is subjected to external impact. It has a structure that can flow up and down.

And, when the buffer cylinders 13 and 22 are installed between the vehicle body 1 and the front and rear axles 10 and 20 on both left and right sides, respectively, so that the front and rear axles 10 and 20 flow up and down. By preventing rapid flow from occurring, the impact of the front and rear axles 10 and 20 is alleviated. Among these buffer cylinders 13 and 22, the buffer cylinder 13 of the front axle 10 is preferably installed at the height of the front axle 10 or higher so that it does not interfere with the front wheel when the front wheel is steered as much as possible. .

Each of the accumulators 163 and 193 filled with compressed gas are connected to the buffer cylinders 13 and 22, so that when the buffer cylinders 13 and 22 are moved up and down, the accumulators 163, 193) due to the expansion and absorption of the nitrogen gas in the front and rear axles 10, 20 is buffered up and down. At this time, the gas is preferably nitrogen gas, and the reason is that it is the most easy to obtain, inexpensive, non-flammable, non-toxic, non-combustible and safe gas among compressible gases.

In addition, shock absorbers 16 and 25 may be further provided in parallel with the buffer cylinders 13 and 22 in order to further mitigate the impact of the front and rear axles 10 and 20. The shock absorbers 16 and 25 may be filled with fillers such as gas and oil therein to increase the damping force of the up and down flow of the buffer cylinders 13 and 22.

On the other hand, there are cases when the tractor moves and stops working.When a working machine such as a bucket, a rotor, a dozer, a trailer, or a plow is mounted on the stopped tractor, the vehicle body (1) depends on the load of the installed working machine. Is lowered, and when the tractor is not equipped with a working machine, the load applied to the vehicle body 1 is small, so that the vehicle body 1 rises.

And, in order to prevent the front axle 10 from moving left and right to the front axle 10, one end of the front axle 10 is hinged to the vehicle body 1 and the other end is hinged to the front axle 10, and the front axle 10 The left and right movement preventing link 17 is provided to prevent the left and right movement of the. Accordingly, the front axle 10 can be moved up and down by the left and right movement preventing link 17, but the movement to the left and right is prevented.

In addition, on the rear axle 20, arms 21 formed long in the longitudinal direction of the vehicle body 1 are formed protruding from both rear axles 20, respectively, and the front ends of the protruding arms 21 are hinged with the vehicle body 1 Thus, the pair of arms 21 and the rear axle 20 are fixed so as not to move left and right, and are provided so as to be movable up and down, thereby eliminating the risk of overturning when turning while the tractor is running.

In particular, in the present invention, when the height of the tractor is turned off while the height of the vehicle body 1 is adjusted according to the load of the working machine mounted on the tractor when the tractor is stopped, the height of the vehicle body 1 of the tractor remains fixed and then started. When turned on, the automatic leveling device 100 is further configured so that the height of the vehicle body 1 is automatically returned to the set original position.

In the automatic leveling device 100 according to the present invention, the buffer cylinders 13 and 22 provided on the front and rear axles 10 and 20 of the vehicle body 1 respectively increase the height of the vehicle body 1 when the tractor is started. The automatic leveling device 100 further includes a sensing means (not shown) for sensing the height of the vehicle body 1, and a control unit according to the sensing signal of the sensing means. It is controlled and operated by (not shown).

On the other hand, the automatic leveling apparatus 100 of the present invention, as shown in Fig. 2, the hydraulic pump 110 for supplying the hydraulic pressure to the hydraulic line 111 by supplying the hydraulic pressure from the hydraulic tank in which the hydraulic pressure is stored, and the hydraulic line 111 ) Is provided in the unloading valve 120 for controlling the supply of hydraulic pressure, and the supply line 133 and the discharge line 143 branching from the hydraulic line 111, respectively, and each buffer cylinder 13, 22 The first and second rising valves 130 and 140 and the first and second lowering valves 130a and 140a for raising or lowering each buffer cylinder 13 and 22, and the first and second rising valves (130) (140) and the first and second lowering valves (130a) (140a) and each buffer cylinder (13, 22) is provided in each of the front and rear lines 150 and 180 connecting the buffer cylinders ( 13) It includes a cushion fixing valve 160, 190 for fixing the cushion of (22).

Here, the first rising valve 130 and the first falling valve 130a are connected to the front line 150 to be connected to the buffer cylinder 13 in the front, and the second rising valve 140 and the second falling The valve 140a is connected to the rear line 180 and is provided to be connected to the buffer cylinder 22 at the rear.

In the vehicle body 1 by the automatic leveling device 100 configured as described above, the vehicle body 1 of the tractor is raised as the hydraulic pressure is supplied through the first and second elevation valves 130 and 140, and the vehicle body 1 The lowering of the tractor is made by the load of the working machine mounted on the body 1 of the tractor.

Meanwhile, the hydraulic line 111 is a line connecting the first and second rising valves 130 and 140 and the first and second lowering valves 130a and 140a from the hydraulic tank, and the hydraulic line 111 includes hydraulic pressure. The pump 110 and the unloading valve 120 are sequentially connected and provided.

The hydraulic pump 110 pressurizes and supplies hydraulic pressure in the hydraulic tank to the hydraulic line 111, and the hydraulic tank is provided with a filter for filtering out foreign substances contained in the hydraulic pressure that is pumped to the hydraulic line 111, and a hydraulic pump. The hydraulic line 111 between the 110 and the unloading valve 120 is further provided with a line filter for filtering foreign substances in hydraulic pressure.

Further, the hydraulic line 111 is provided with a first branch line 112 branched from the hydraulic line 111 and connected to the hydraulic tank, and the first branch line 112 is provided with an unloading valve 120. The unloading valve 120 has a bypass flow path and a blocking flow path, respectively, and the bypass flow path is a flow path connecting the first branch line 112 to the hydraulic tank, and the hydraulic pressure supplied to the hydraulic line 111 is controlled. The first branch line 112 is bypassed to the hydraulic tank, and the blocking passage is a passage blocking the passage of the first branch line 112.

In particular, the unloading valve 120 maintains the unrotating state by connecting the first branch line 112 by the bypass flow path in normal times, and then, when the first and second rising valves 130 and 140 are operated, the unloading valve ( 120 is locked and the flow path of the first branch line 112 is blocked by the blocking flow path, thereby increasing the rising pressure that raises the buffer cylinders 13 and 22, and loading the buffer cylinders 13 and 22, that is, raising it. Will be ordered.

In addition, the first branch line 112 further includes a second branch line 113 branched from the first branch line 112 and connected to the hydraulic tank, and a relief valve 114 is provided on the second branch line 113. Is equipped. The relief valve 114 is normally provided in a state in which the flow path of the second branch line 113 is blocked, and a pressure greater than the rising pressure that raises the buffer cylinders 13 and 22 acts on the hydraulic line 111 When the relief valve 114 is operated, the flow path of the second branch line 113 is connected. Accordingly, by returning the hydraulic pressure of a large pressure acting on the hydraulic line 111 to the hydraulic tank through the second branch line 113, it is possible to safely protect the pipeline from overload.

On the other hand, the front and rear buffer cylinders 13 and 22 provided on the front and rear axles 10 and 20 of the vehicle body 1, respectively, are provided with the first and second rising valves 130, 140, and the first, 2 Bar provided to be raised and lowered by the lowering valves 130a and 140a, the first and second rising valves 130 and 140 are provided connected to the supply line 133 branching from the hydraulic line 111, and The 1,2 lowering valves 130a and 140a are provided connected to the discharge line 143 branching from the hydraulic line 111.

The first and second rising valves 130 and 140 transmit hydraulic pressure transferred to the supply line 133 by the hydraulic pump 110 through the front line 150 and the rear line 180, respectively, to the buffer cylinders 13 ) (22) to raise the vehicle body 1 through the stretching action of each buffer cylinder (13, 22), and the first and second lowering valves (130a) (140a) are mounted on the vehicle body (1). The hydraulic pressure discharged from the buffer cylinders 13 and 22 by the contraction action of the buffer cylinders 13 and 22 by the load of the working machine is discharged through the front line 150 and the rear line 180 through the discharge line 143 ).

In addition, the first rising valve 130 and the first falling valve 130a are independently connected to one front line 150 and provided, and the second rising valve 140 and the second falling valve 140a are Each of the rear lines 180 is independently connected to and provided, so that hydraulic pressure is supplied or discharged to each of the buffer cylinders 13 and 22 to expand and contract the buffer cylinders 13 and 22.

Meanwhile, the first rising valve 130, the first falling valve 130a, the second rising valve 140, and the second falling valve 140a are respectively a single supply line 133 and a single discharge line 143 By being provided to be connected to each of the buffer cylinders 13, 22, the load of the working machine acting on the supply line 133 and the discharge line 143 is connected thereto the rising valve 130, 140 and the down valve (130a) ) (140a), as well as being distributed and operated, it is possible to simplify the flow path thereof.

These first and second rising valves 130 and 140 and the first and second lowering valves 130a and 140a are provided to be sequentially connected to the supply line 133 and the discharge line 143, respectively, as power is supplied. The supply line 133 and the discharge line 143 are opened. At this time, the supply line 133 and the discharge line 143 are raised flow paths by the rising valves 130 and 140 or the down valves 130a and 140a. Alternatively, it is formed as a descending passage, and accordingly, each of the buffer cylinders 13 and 22 contracts or extends.

The rising valves 130 and 140 and the down valves 130a and 140a have one open flow path 131, 131a, 141, 141a, and a closed flow path 132 closed by a check valve. 132a) 142, 142a are provided respectively, and the open flow paths 131, 131a, 141, 141a and the closed flow paths 132, 132a, 142, 142a are selectively supplied with the supply line 133 ) And is provided to be connected to the discharge line 143, respectively.

Each of the closing flow paths 132, 132a, 142, 142a, except for the lifting of the buffer cylinders 13, 22, is the ascending valves 130, 140 and the descending valves 130a, 140a. It is connected to the supply line 133 and the discharge line 143 and provided in a state in which the flow path of each line 133 and 143 is blocked, and when the buffer cylinders 13 and 22 are elevated, the rising valves 130 and 140 ) Or the lowering valves (130a) (140a) are supplied with power so that the opening flow paths (131) (131a) (141) (141a) of each valve (130) (130a) (140) (140a) are each line (133) It is connected to 143 to secure the flow path of each line 133, 143.

In particular, a plurality of check valves are provided in the closing flow paths 132, 132a, 142, and 142a so as to be opened in opposite directions, that is, from the inside to the outside of each valve, thereby blocking the inflow of hydraulic pressure from the source and closing it.

In addition, the rising valves 130, 140 and the down valves 130a, 140a block the flow path by a pair of check valves that are opened in the reverse direction together with the cushion fixing valves 160 and 190 to be described later, It is equipped with a puppet type valve that eliminates leaks.

On the other hand, the front line 150 connects the first rising valve 130 and the first falling valve 130a to the front buffer cylinder 13, and the rear line 180 is the second rising valve 140 and the second 2 It is provided to connect the lowering valve (140a) to the rear buffer cylinder (22).

In addition, check valves 153 and 183 are provided in the front line 150 and the rear line 180 as described above, respectively, and each line 150 and 180 bypasses the check valves 153 and 183. Bypass lines 151 and 181 are provided, and each orifice 152 and 182 is provided in the bypass lines 151 and 181.

The check valves 153 and 183 provided in this way are each line 150 and 180 only when hydraulic pressure is applied from the side of each valve 130, 130a, 140, 140a to the buffer cylinder 13, 22. ) To allow hydraulic pressure to flow and prevent reverse flow.

In addition, the orifices 152 and 182 are provided to control the amount of hydraulic pressure discharged from the buffer cylinders 13 and 22 to mitigate the sudden descent of the vehicle body due to the weight of the tractor and the working machine.

And, between the front and rear lines 150, 180 and each of the buffer cylinders 13, 22, the cushion fixing valves 160 and 190 are connected to each other, and more specifically, the cushion fixing valves 160, ( 190 is provided on the front and rear lines 150 and 180 between the accumulators 163 and 193 and the buffer cylinders 13 and 22 to be described later.

The cushion fixing valves 160 and 190 are provided in a one-to-one correspondence with each of the buffer cylinders 13 and 22 to control buffering, that is, a cushion of the corresponding buffer cylinders 13 and 22.

These cushion fixing valves 160 and 190 are composed of a puppet type valve similar to the above-described rising and falling valves 130, 130a, 140, 140a, and one open flow path 161, 191 and , Closed flow paths 162 and 192 closed by a check valve are provided, respectively, and these open flow paths 161 and 191 and the closed flow paths 162 and 192 are of the front and rear lines 150 and 180. It is provided to connect or block the accumulators 163, 193 and the buffer cylinders 13, 22 to be described later by selectively connected to the flow path.

Accordingly, each of the cushion fixing valves 160 and 190 as described above is provided by the closing flow paths 162 and 192 during the stop operation of the tractor (including when the moving speed is ultra-low). 180) is locked to block the connection between the respective buffer cylinders 13, 22 and the accumulators 163, 193, thereby temporarily stopping the buffering function of the buffer cylinders 13, 22, and the open passage when the tractor is running. The flow paths of the lines 150 and 180 are connected by 161 and 191, and the buffer cylinders 13, 22 and the accumulators 163 and 193 are connected to each other. As is buffered, the shock transmitted according to the road surface condition is absorbed.

On the other hand, among these cushioning valves, each of the accumulators 163 are connected to each other in a one-to-one correspondence to both the front cushioning valves 160, and one accumulator 193 is provided in the rear cushioning valves 190. Is provided connected to both cushion fixing valves 190 at the same time.

In this way, the front two cushioning fixing valves 160 are independently provided, and the rear two cushioning fixing valves 190 are provided to be integrally connected, so that, like the arm 21 of the rear axle 20 described above, This is to prevent a rollover accident in advance.

That is, when both cushion fixing valves 190 of the rear axle 20 are provided independently, the load of the tractor is shifted toward the outer circumference side in the turning direction by centrifugal force during the turning during the driving of the tractor. The front and rear cushion fixing valves 160 and 190 are contracted at the same time, so that the tractor is inclined to the outside and overturned, and an accident may occur. By connecting the cushion fixing valves 190 of the rear axle 20 integrally Accordingly, when the tractor is turning, the displacement of the load due to the centrifugal force of the tractor is distributed to both the rear cushion fixing valves 190 to prevent excessive inclination, so that a rollover accident of the tractor can be prevented in advance.

In addition, the accumulators 163 and 193 are provided with diaphragms 164 and 194 that divide a space therein, and the upper portion of the diaphragm 164 and 194, that is, to which each line 150 and 180 is connected. Nitrogen gas is stored and provided on the opposite side, and hydraulic pressure is provided to enter and exit the lower part, that is, the side connected to each of the lines 150 and 180 to buffer the buffer cylinders 13 and 22.

In addition, the front line 150 between the front cushioning valves 160 as described above is provided with left and right fixing valves 170 for controlling the hydraulic flow between the front buffer cylinders 13, and the left and right fixing valves ( 170) is also composed of a puppet type valve having one open flow path 171 and one closed flow path 172 closed by a check valve, similar to the above-described cushion fixing valves 160 and 190.

The left and right fixing valves 170 are connected to the front line 150 by the open flow path 171 when the tractor is traveling at a low speed or when traveling at a low speed, thereby enabling a buffer action as both buffer cylinders 13 in the front are connected. When parking, that is, when the tractor is stopped working or when driving at high speed, the front line 150 is closed by the closing flow path 172 to block both the front buffer cylinders 13, and in the parking state, both front cushion fixing valves ( 160) Since the buffer cylinder 13 in the front is also in a locked state, the buffer function is temporarily suspended, so that the overturning of the tractor can be prevented.

Therefore, by the automatic leveling device 100 configured as described above, the buffer function of the buffer cylinders 13 and 22 is completely blocked and stopped when the tractor is working or when the tractor is running at high speed. The shock absorbing function of the cylinders 13 and 22 is restored to its original state, so that the shock absorbing can be performed.

However, despite the control by the automatic leveling device 100 as described above, as the load of the work object provided in the working machine is added together with the load of the working machine mounted on the tractor, the buffer cylinders 13 and 22 A hydraulic leak may occur in each line connected to ), and when the lock of the buffer cylinders 13 and 22 is released by the leak, a large accident occurs due to a malfunction in which the buffer cylinders 13 and 22 are lowered. Can be.

Therefore, in the present invention, even if a leak occurs in all hydraulic lines connected to the buffer cylinders 13 and 22, the safety means that can prevent major accidents by mechanically blocking the lifting of the buffer cylinders 13 and 22 Provides.

That is, as shown in FIGS. 3A and 3B, brackets 13a and 22a are formed on the outer circumferences of the buffer cylinders 13 and 22, and the rods 14 entering and leaving the buffer cylinders 13 and 22 Brackets 14a and 23a corresponding to the brackets 13a and 22a of the buffer cylinders 13 and 22 are formed on the outer periphery of 23, and both brackets 13a, 14a, 22a, 23a In the fixing holes 13b, 14b, 22b, 23b, which are provided to match each other when the rods 14 and 23 are completely inserted into the buffer cylinders 13 and 22 are formed, the fixing holes 13b )(14b)(22b)(23b), each of the fixing pins (15) (24) is penetrated and coupled to the buffer cylinder (13) (22) by structurally blocking the withdrawal of the rod (14) (23) from the source. It is possible to prevent the malfunction of the cylinders 13 and 22 in advance.

These fixing pins 15 and 24 may be provided to be constrained through a string such as a wire on the outer periphery of the buffer cylinders 13 and 22, and furthermore, the brackets 13a of the buffer cylinders 13 and 22 ) A storage hole (13c) (22c) separate from the fixing hole (13b) (22b) is formed in (22a), and the fixing pins (15) (24) are connected through the storage hole (13c) (22c). Provided in a state, it is possible to prevent the loss of the fixing pins (15, 24).

The operation relationship of the automatic leveling device according to the present invention as described above will be described.

First, when the engine is turned on for movement after completing the work using the tractor, the height of the vehicle body 1 by the sensing means is input to the control unit, and the control unit is thus the unloading valve 120 and the first and second rising valves 130 By operating 140, the unloading valve 120 is closed and the rising valves 130 and 140 are opened.

That is, as the unloading valve 120 is locked, the first branch line 112 is closed, so that all hydraulic pressure pumped by the hydraulic pump 110 is supplied to the supply line 133 through the hydraulic line 111. .

In addition, the rising valves 130 and 140 are connected to the front line 150 and the rear line 180 by their open flow paths 131 and 141 respectively to secure a flow path, thereby securing a hydraulic pump ( The hydraulic pressure by 110 is supplied to the front and rear lines 150 and 180 respectively through the supply line 133 to extend the buffer cylinders 13 and 22 provided on the front and rear axles 10 and 20. Will be ordered.

Accordingly, the vehicle body 1 of the tractor that has been lowered is forcibly raised to return to its original position, and at this time, the lowering valves 130a and 140a have their closing flow paths 132a and 142a connected to the supply line 133 and the front and rear It is provided between the lines 150 and 180 and is locked.

In this state, when the tractor moves, i.e., runs, the cushion fixing valves 160 and 190 connected to the buffer cylinders 13 and 22 are operated so that the flow path of the cushion fixing valves 160 and 190 as shown in FIG. By opening, each buffer cylinder 13, 22 is provided in communication with each accumulator 163, 193, so that the shock transmitted from the road surface during driving can be buffered by the expansion and contraction operation of the buffer cylinders 13, 22. You will be able to.

Thereafter, in the case of connecting the working machine to the tractor to work, the rising valves 130 and 140 are locked by the control unit according to the work mode, and the lowering valves 130a and 140a are opened and the front and rear lines 150 ) 180 and a flow path of the discharge line 143 is secured.

Then, the buffer cylinders 13 and 22 are contracted by the load of the working machine connected to the tractor, and the hydraulic pressure discharged from the buffer cylinders 13 and 22 in the process of contracting is the front and rear lines 150 and 180 And it is introduced into the discharge line 143 through the lowering valves (130a) (140a) and returned to the hydraulic tank.

Thereafter, when the vehicle body 1 is lowered to a certain height and the lowering is completed, the lowering valves 130a, 140a and each of the cushion fixing valves 160 and 190 are locked by the control unit as shown in FIG. 2 to flow hydraulic pressure. Due to this limitation, the body 1 of the tractor can be maintained in a lowered state, and in this state, the engine is turned off and the working machine is used.

And, since the load applied to the vehicle body 1 of the tractor by the working machine in the above state may be large, both fixing holes 13b and 14b between the buffer cylinders 13, 22 and the rods 14 and 23 ) (22b) (23b) by inserting the fixing pins (15) (24) into the automatic leveling device (100) even if a hydraulic leak occurs, the buffer cylinder (13) (22) remains structurally securely locked. As a result, the buffer cylinders 13 and 22 are not contracted and are firmly maintained in a fixed state, so that the vehicle body 1 can be safely operated in a state that prevents arbitrary descending.

Thereafter, when the tractor is started after completion of the work, the flow path of the automatic leveling device 100 is secured as shown in FIG. 4, so that the buffering function by the buffer cylinders 13 and 22 is possible.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the present invention is not limited thereto, and those of ordinary skill in the art within the spirit of the present invention It is clear that the transformation or improvement is possible.

All simple modifications to changes of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: body 10: front axle
11: upper link 12: lower link
13: buffer cylinder 13a, 14a: bracket
13b,14b: fixed hole 13c: storage hole
14: rod 15: fixing pin
16: shock absorber 17: left and right movement prevention link
20: rear axle 21: arm
22: buffer cylinder 22a, 23a: bracket
22b,23b: fixed hole 22c: storage hole
23: rod 24: fixing pin
25: shock absorber 100: automatic leveling device
110: hydraulic pump 111: hydraulic line
112,113: first and second branch lines 114: relief valve
120: unloading valve 130,140: first and second rising valves
131,141: open flow path 132,142: closed flow path
130a,140a: first and second lowering valves 131a,141a: open flow path
132a,142a: closed flow path 133: supply line
143: discharge line 150: front line
151: bypass line 152: orifice
153: check valve 160: cushion fixing valve
161: open flow path 162: closed flow path
163: accumulator 164: diaphragm
170: left and right fixed valves 171: open flow path
172: closed passage 180: rear line
181: bypass line 182: orifice
183: check valve 190: cushion fixing valve
191: open flow path 192: closed flow path
193: accumulator 194: diaphragm

Claims (5)

An automatic leveling device for a tractor body comprising a buffer cylinder that is installed between the body of the tractor and the front and rear axles, respectively, to buffer the vehicle body being raised and lowered,
The tractor body automatic leveling device includes an unloading valve that controls hydraulic pressure by a hydraulic pump to be supplied when a buffer cylinder is raised;
A rising valve and a falling valve provided between the unloading valve and each buffer cylinder to raise or lower each buffer cylinder;
Automatic leveling device for a tractor body comprising: a cushion fixing valve provided between the rising valve and the falling valve and each buffer cylinder to fix the cushion of each buffer cylinder.
The method according to claim 1,
An automatic leveling device for a tractor vehicle body provided with an orifice for mitigating the sudden descent of the vehicle body, provided in the hydraulic line between the rising valve and the falling valve and each cushion fixing valve.
The method according to claim 1,
Tractor equipped with a single accumulator to buffer the rear buffer cylinder by connecting both cushion fixing valves to the front cushion fixing valve and each accumulator to buffer the front buffer cylinder, and to the rear cushion fixing valve. Auto body leveling device.
The method of claim 3,
Each cushion fixing valve is locked when the tractor is stopped, blocking the connection between each buffer cylinder and the accumulator to stop the buffer function of the buffer cylinder.
The method according to claim 1,
The left and right fixed valves are provided between the front two cushioning valves to prevent the tractor from overturning by fixing the hydraulic flow between the front two buffer cylinders when stopping or running at high speed. Automatic leveling device for the body of the tractor that connects the hydraulic flow between the two.

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