KR102251962B1 - The oil hydraulic system for a forklift truck - Google Patents

Abstract

The present invention relates to a hydraulic system for a forklift, and in the present invention, on the oil discharge path of the second pump, under the condition of <low idle of the engine, the gear is located in the forward mode or the reverse mode, and the work device is In the case of tilt-in or lift, an oil return processing unit> that can selectively return the oil discharged by the second pump to the oil tank, was taken to be additionally arranged, so that the forklift driver Even if the work of tilt-in or lift the work device is performed while the gear of the forklift is placed in the forward mode or the reverse mode under the engine's low idle condition, the second pump From the side, the oil stored in the oil tank is induced to prevent high-pressure discharge through the control valve (that is, the oil discharged by the second pump is induced to be returned to the oil bank), and through this, it is caught on the engine side. By lowering the possible load to a minimum, it is possible to guide the forklift driver so as not to be subjected to an uncomfortable situation such as a sudden shutdown of the forklift during work.

Description

The oil hydraulic system for a forklift truck

The present invention relates to a hydraulic system installed in a forklift, and more particularly, on the oil discharge path of the second pump, the gear is positioned in the forward mode or the reverse mode under the condition of <low idle of the engine, In case the work device is tilt-in or lifted, an oil return processing unit> capable of selectively returning the oil discharged by the second pump to the oil tank was taken to be additionally arranged. Even if the forklift driver tilts-in or lifts the work device while placing the forklift's gear in the forward or reverse mode under the engine's low idle condition, On the second pump side, the oil stored in the oil tank is induced to prevent high-pressure discharge through the control valve (i.e., the oil discharged by the second pump is induced to be returned to the oil bank), and through this, the engine The present invention relates to a hydraulic system for a forklift that can guide a forklift driver to avoid uncomfortable situations such as sudden shutdown of a forklift during work by reducing the load that may be applied to the side to a minimum.

Recently, with the rapid development of forklift related technologies, the hydraulic system installed in the forklift is also undergoing wide development.

For example, Korean Patent Registration No. 10-1023744 (name: hydraulic system of a forklift) (announced on March 25, 2011), Korean Patent Publication No. 10-2013-128850 (name: hydraulic system of a forklift) (2013.11. 27), Korean Patent Registration No. 10-1343831 (name: hydraulic system of a forklift) (announced on Dec. 20, 2013), etc. disclose an example of a hydraulic system for a forklift according to such a conventional technology in more detail. have.

On the other hand, as shown in FIG. 1, the hydraulic system 1 for a forklift according to the prior art includes an electronic control unit (ECU) 10, a first pump 4 and a second pump 5 A pump module 3 having) and an engine 2 that is controlled by the ECU 10 and acts as a power source for the first pump 4 and the second pump 5 on the pump module 3 side, While being turned on/off according to the control of the ECU 10, the oil (Oil, for example, hydraulic oil) discharged by the first pump 4 and the second pump 5 is transferred through the oil distribution line 14 to the working device ( A control valve 7 or the like that supplies to the 9) side and drives the work device 9 (eg, a tilt cylinder, a lift cylinder, an attachment, etc.) is intimately combined.

In this case, on the side of the ECU 10, for example, <the role of detecting/controlling unnecessary pressure increase when operating the work device 9 while taking a structure electrically connected to the hydraulic pressure sensor 8>, <The role of operating the engine 2 according to the driving state of the accelerator 11, gear 16, etc., while taking a structure electrically connected to the accelerator 11, engine 2, gear 16, etc.> , <the role of controlling the on/off state of the control valve 7 while taking a structure electrically connected to the control valve 7> and the like.

In addition, from the side of the first pump 4 and the second pump 5, the oil (e.g., hydraulic oil) stored in the oil tank 6 is driven according to the operating conditions of the engine (2), gear (6), etc. ) Through the oil distribution lines 12 and 13 to the control valve 7 to perform the role>.

Under such a conventional system, on the forklift driver's side, depending on the situation, while positioning the gear 16 of the forklift in the forward mode or the reverse mode under the condition of <low idle of the engine 2, the working device 9 Tilt-in or lift operation> proceeds.

However, as described above, the forklift driver tilts the work device 9 while placing the gear 16 of the forklift in the forward mode or the reverse mode under the <low idle condition of the engine 2. When the (Tilt-in) or lift operation> is performed, the oil stored in the oil tank 6 not only the first pump 4 but also the second pump 5 (for example, hydraulic oil) By discharging high pressure to the control valve 7 through the oil distribution lines 12 and 13, an excessive load corresponding to the first pump 4 as well as the second pump 5 is applied to the engine 2 side. As a result, the forklift driver is bound to face uncomfortable situations such as sudden shutdown of the forklift during work.

Of course, in the case where the forklift is suddenly turned off during work, the forklift driver has no choice but to bear the damage that the overall work efficiency is significantly lowered.

Korean Patent Registration No. 10-1023744 (Name: hydraulic system of forklift) (announced on March 25, 2011) Republic of Korea Patent Publication No. 10-2013-128850 (name: forklift hydraulic system) (published on November 27, 2013) Korean Patent Registration No. 10-1343831 (Name: hydraulic system of forklift) (announced on December 20, 2013)

Accordingly, an object of the present invention is that the gear is positioned in the forward mode or the reverse mode on the oil discharge path of the second pump, under the condition of <low idle of the engine, and the working device is tilt-in. ) Or a lift, an oil return processing unit> that can selectively return the oil discharged by the second pump to the oil tank> is additionally placed, so that the forklift driver can reduce the engine's low idle rate. ) Under the condition, the forklift gear is placed in the forward mode or the reverse mode, and even if the work device is tilted-in or lifted, the second pump is stored in the oil tank. Induces the existing oil to not be discharged at high pressure through the control valve (i.e., induces the oil discharged by the second pump to be returned to the oil bank), thereby reducing the load that may be applied to the engine to a minimum. By zooming, the forklift driver's side is to guide the forklift in an uncomfortable situation such as suddenly turning off the forklift during work.

Other objects of the present invention will become more apparent from the following detailed description and accompanying drawings.

In the present invention, in order to achieve the above object, an electronic control unit (ECU); A gear and an engine controlled by the ECU; A first pump and a second pump that are driven according to operating states of the gear and engine and discharge oil stored in the oil tank; A control valve that is controlled by the ECU and supplies the oil discharged by the first and second pumps to a working device to drive the working device; It is disposed on the oil discharge path of the second pump, the gear is located in the forward mode or the reverse mode under the low idle condition of the engine, and the working device is tilt-in or In the case of being lifted, it includes an oil return processing unit that returns the oil discharged by the second pump to the oil tank, and the oil return processing unit communicates with the ECU, while a flow direction change indicator valve that is in a turn-on state when the gear is positioned in a forward mode or a reverse mode and the work device is tilt-in or lifted under an idle) condition; In a state disposed on the oil discharge path of the second pump, it is electrically connected to the flow direction change instruction valve, and when the flow direction change instruction valve is in a turn-on state, discharged by the second pump A flow direction switching valve for changing the direction of oil and returning the oil to the oil tank; In a state disposed on the oil discharge path of the second pump, it is electrically connected to the flow direction switching valve, and only when the pressure of the oil discharged from the second pump corresponds to a preset value, the turn-on state By achieving a pressure condition control valve that allows the flow direction switching valve to change the direction of the oil discharged by the second pump to the oil tank side only when the pressure of the oil corresponds to a preset value. Disclosed is a hydraulic system for a forklift, comprising:

In the present invention, on the oil discharge path of the second pump, under the condition of <low idle of the engine, the gear is positioned in the forward mode or the reverse mode, and the work device is tilt-in or lift ( Lift), an oil return processing unit> that can selectively return the oil discharged by the second pump to the oil tank, is additionally placed, so that the forklift driver is under the condition of low idle of the engine, Even if the forklift gear is placed in the forward mode or the reverse mode and the work device is tilted in or lifted, the oil stored in the oil tank is removed from the second pump side. Because it induces the control valve not to discharge high pressure (that is, because it induces the oil discharged by the second pump to be returned to the oil bank), under the implementation environment of the present invention, the load on the engine is minimal at the forklift driver side. You will be able to enjoy the lowered effect, and in the end, you will not be in an uncomfortable situation such as the forklift suddenly turning off during work.

1 is an exemplary view conceptually showing a hydraulic system for a forklift according to the prior art.
2 is an exemplary view conceptually showing a hydraulic system for a forklift according to the present invention.
3 is an exemplary view conceptually showing a detailed configuration of an oil return processing unit according to an embodiment of the present invention.
4 is an exemplary view conceptually showing a detailed configuration of an oil return processing unit according to another embodiment of the present invention.

Hereinafter, a hydraulic system for a forklift according to the present invention will be described in more detail with reference to the accompanying drawings.

As shown in FIG. 2, the hydraulic system 100 for a forklift according to the present invention includes an electronic control unit (ECU) 110, a first pump 104 and a second pump 105. While being controlled by the pump module 103 and the ECU 110, the engine 102 acting as a power source of the pump module 103 side first pump 104 and the second pump 105, and the ECU 110 ), the oil discharged by the first pump 104 and the second pump 105 (Oil, for example, hydraulic oil) is transferred to the working device 109 through the oil distribution line 114 By supplying, the control valve 107 and the like for driving the working device 109 (eg, a tilt cylinder, a lift cylinder, an attachment, etc.) are intimately combined.

In this case, on the ECU 110 side, for example, <the role of detecting/controlling unnecessary pressure increase when operating the work device 109 while taking a structure electrically connected to the hydraulic pressure sensor 108>, <The role of operating the engine 102 according to the driving state of the accelerator 111, gear 116, etc., while taking a structure electrically connected to the accelerator 111, engine 102, gear 116, etc.> , <the role of controlling the on/off state of the control valve 107 while taking a structure electrically connected to the control valve 107>, and the like.

In addition, from the side of the first pump 104 and the second pump 105, it is driven according to the operating state of the engine 102 and gear 116, and the oil stored in the oil tank 106 (e.g., hydraulic oil ) To the control valve 107 through the oil distribution lines 112 and 113.

On the other hand, even under the system of the present invention, depending on the situation on the forklift driver's side, while positioning the gear 116 of the forklift in the forward mode or the reverse mode under the condition of <low idle of the engine 102, the working device The operation of tilt-in or lift (109)> proceeds.

Of course, even under this situation, as in the prior art, if no separate measures are taken, the oil stored in the oil tank 106 in the first pump 104 as well as the second pump 105 (for example, hydraulic oil ) Is discharged to the control valve 107 through the oil distribution lines 112 and 113, so that an excessive load corresponding to the first pump 104 as well as the second pump 105 is applied to the engine 102 side. As a result, the forklift driver is bound to face uncomfortable situations such as sudden shutdown of the forklift during work.

Under such a sensitive situation, as shown in FIG. 2, in the present invention, on the oil distribution line 115, which is the oil discharge path of the second pump 105, <under the low idle condition of the engine 102 , When the gear 116 is positioned in the forward mode or the reverse mode, and the work device 109 is tilt-in or lifted, the oil discharged by the second pump 105 is oiled. A measure is taken to additionally arrange an oil return processing unit 120> which can be selectively returned to the oil tank 106 through the distribution line 117.

At this time, as shown in Figure 3, while taking communication with the ECU 110, the oil return processing unit 120 according to an embodiment of the present invention, under the low idle condition of the engine 102, the gear When 116 is located in the forward mode or the reverse mode, and the work device 109 is tilt-in or lifted, correspondingly, the flow direction changes to form a series of turn-on states. In a state disposed on the indication valve 121 and the oil distribution line 115 that is the oil discharge path of the second pump 105, it is electrically connected to the flow direction changeover indication valve 121, and the flow direction changeover indication valve When 121 is in the turn-on state, the direction of the oil discharged by the second pump 105 is switched to the oil distribution line 114, and the flow direction is changed to return the oil to the oil tank 106. The valve 122 takes a systematically combined configuration.

Under the system of the present invention, when the forklift driver performs a normal operation and takes an action such as operating the accelerator 111, the flow direction change instruction valve 121 is turned off. You will stay in the state.

Of course, when the flow direction change indicator valve 121 maintains the turn-off state, the flow direction selector valve 122 also does not perform a separate oil direction change operation, and as a result, the second pump 105 ), the oil discharged through the oil distribution lines 115 and 113 undergoes a high-pressure discharge procedure to the control valve 107 (see FIG. 3).

However, depending on the situation, the forklift driver positions the gear 116 of the forklift in the forward mode or the reverse mode under the <Low idle condition of the engine 102, and tilts the working device 109 ( When the operation of tilt-in or lift is performed>, the flow direction change indicator valve 121 communicates with the ECU 110, and the corresponding situation (that is, the low-speed idle of the engine 102) is performed. idle) condition, the gear 116 is positioned in the forward mode or the reverse mode, and the working device 109 is tilt-in or lifted), and immediately after confirming the It changes the state to a turn-on state.

Of course, according to the above procedure, when the flow direction change instruction valve 121 is changed to the turn-on state, the flow direction changeover valve 122 is immediately operated and discharged by the second pump 105 The direction of the oil is changed to the oil distribution line 114 side, and through this, a procedure of returning the oil to the oil tank 106 proceeds.

Naturally, according to the above procedure, when the direction of the oil discharged by the second pump 105 is switched to the oil distribution line 114 and the corresponding oil is returned to the oil tank 106, the engine 102 Correspondingly, it can be naturally placed in a situation where its own load is reduced to a minimum, and as a result, on the forklift driver's side, under the condition of <low idle of the engine 102, the gear 116 of the forklift is in the forward mode or While positioning the work device 109 in the reverse mode, tilt-in or lift the work device 109, while not being in an uncomfortable situation such as suddenly turning off the forklift during the operation, Without much difficulty, you can enjoy a wide range of benefits of improving overall work efficiency.

As described above, in the present invention, on the oil discharge path of the second pump 105, under the condition of <low idle of the engine 102, the gear 116 is positioned in the forward mode or the reverse mode, and the working device When 109 is tilt-in or lifted, the oil return processing unit 120 capable of selectively returning the oil discharged by the second pump 105 to the oil tank 106 Taking measures to add >, the forklift driver tilts the work device 109 while placing the gear 116 of the forklift in the forward mode or the reverse mode under the low idle condition of the engine 102. -Even if the operation of tilt-in or lift is performed, the second pump 105 side induces the oil stored in the oil tank 106 to be prevented from discharging high pressure to the control valve 107 Because (that is, because it induces the oil discharged by the second pump to be returned to the oil bank), under the implementation environment of the present invention, the forklift driver side has the effect of lowering the load on the engine 102 to a minimum. You will be able to enjoy it, and in the end, you will not be in an uncomfortable situation such as the forklift suddenly turning off during work.

On the other hand, as shown in Fig. 4, in another embodiment of the present invention, the oil return processing unit 120 is in addition to the flow direction change indicator valve 121, the flow direction selector valve 122, and the like, a pressure condition control valve ( 123).

At this time, from the side of the pressure condition control valve 123 <Structure arranged on the oil distribution line 115, which is the oil discharge path of the second pump 105>, <Structure electrically connected to the flow direction switching valve 122> While taking the same, only when the pressure of the oil discharged from the second pump 105 corresponds to a preset value, an operation of forming a turn-on state is selectively implemented.

At this time, the flow direction selector valve 122 is operated only when the flow direction selector valve 121 and the pressure condition control valve 123 are both in the turn-on state, and the second pump 105 Accordingly, the direction of the discharged oil is changed to the oil tank 106 side.

Of course, as described above, when the pressure condition control valve 123 side, only when the pressure of the oil discharged from the second pump 105 corresponds to a preset value, the operation of forming the turn-on state is selectively implemented. , The flow direction switching valve 122 also changes the direction of the oil discharged by the second pump 105 to the oil tank 106 only when the oil pressure corresponds to a preset value. Under the circumstances, the forklift driver's side can widely enjoy, for example, the advantage of being able to operate the oil return processing unit 120 of the present invention only under a desired load condition (or oil pressure condition).

On the other hand, even under such other implementations of the present invention, when a forklift driver performs a normal operation and takes an action such as operating the accelerator 111, the flow direction change instruction valve 121, the pressure condition control valve On the (123) side, the turn-off state is maintained.

Of course, when the flow direction change indicator valve 121, the pressure condition control valve 123, etc. are maintained in a turn-off state, the flow direction change valve 122 also does not perform a separate oil direction change operation. As a result, the oil discharged by the second pump 105 undergoes a high-pressure discharge procedure to the control valve 107 through the oil distribution lines 115 and 113 (see FIG. 4 ).

However, depending on the situation, the forklift driver positions the gear 116 of the forklift in the forward mode or the reverse mode under the <Low idle condition of the engine 102, and tilts the work device 109 ( When the operation of tilt-in or lift is performed>, the flow direction change indicator valve 121 communicates with the ECU 110 to obtain a corresponding situation (that is, the low-speed idle of the engine 102). idle) condition, the gear 116 is positioned in the forward mode or the reverse mode, and the working device 109 is tilt-in or lifted), and immediately after confirming the It changes the state to a turn-on state.

In addition, depending on the situation, the forklift driver positions the gear 116 of the forklift in the forward mode or the reverse mode under the <Low idle condition of the engine 102, and tilts the work device 109 ( In an environment where a tilt-in) or a lift operation> is performed, when the pressure of the oil discharged from the second pump 105 corresponds to a preset value, the pressure condition control valve 123 also has its own It changes the state to a turn-on state.

Of course, according to the above procedure, when the flow direction change instruction valve 121, the pressure condition control valve 123, and the like are changed to a turn-on state, the flow direction selector valve 122 immediately operates in an operating state, 2 The direction of the oil discharged by the pump 105 is changed to the oil distribution line 114 side, and through this, a procedure of returning the oil to the oil tank 106 proceeds.

Naturally, according to the above procedure, when the direction of the oil discharged by the second pump 105 is switched to the oil distribution line 114 and the corresponding oil is returned to the oil tank 106, the engine 102 Correspondingly, it can be naturally placed in a situation where its own load is reduced to a minimum, and as a result, on the forklift driver's side, under the condition of <low idle of the engine 102, the gear 116 of the forklift is in the forward mode or While positioning the work device 109 in the reverse mode, tilt-in or lift the work device 109, while not being in an uncomfortable situation such as suddenly turning off the forklift during the operation, Without much difficulty, you can enjoy a wide range of benefits of improving overall work efficiency.

As described above, in this manner, in another embodiment of the present invention, on the oil discharge path of the second pump 105, under the condition of <low idle of the engine 102, the gear 116 is in the forward mode or backward It is located in the mode, and when the work device 109 is tilt-in or lifted, the oil discharged by the second pump 105 can be selectively returned to the oil tank 106. Taking measures to additionally arrange the oil return processing unit 120>, the forklift driver placed the gear 116 of the forklift in the forward mode or the reverse mode under the low idle condition of the engine 102, Even if the operation of tilt-in or lift the work device 109 is performed, the oil stored in the oil tank 106 is transferred from the second pump 105 side to the control valve 107 ) To prevent high-pressure discharge (that is, because it induces the oil discharged by the second pump to be returned to the oil bank), even under another implementation environment of the present invention, the forklift driver You can enjoy the effect of lowering the load applied to the minimum, and eventually, you will not be faced with an uncomfortable situation such as the forklift suddenly turning off during work.

The present invention has an overall useful effect in various fields where it is necessary to prevent unnecessary start-off phenomenon.

And, in the above, although specific embodiments of the present invention have been described and illustrated, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or point of view of the present invention, and such modified embodiments should fall within the scope of the appended claims of the present invention.

1,100: hydraulic system for forklift
2,102: engine
3,103: pump module
4,104: the first pump
5,105: second pump
6,106: oil tank
7,107: control valve
8,108: hydraulic pressure sensor
9,109: work equipment
10,110: ECU
11,111: accelerator
12,13,14,112,113,114,115,117: Oil distribution line
16,116: gear
120: oil return processing unit
121: flow direction change indicator valve
122: flow direction selector valve
123: pressure condition control valve

Claims (4)

An electronic control unit (ECU);
A gear and an engine controlled by the ECU;
A first pump and a second pump that are driven according to operating states of the gear and the engine and discharge oil stored in the oil tank;
A control valve that is controlled by the ECU and supplies oil discharged by the first and second pumps to a working device to drive the corresponding working device;
It is disposed on the oil discharge path of the second pump, the gear is positioned in the forward mode or the reverse mode under the low idle condition of the engine, and the working device is tilt-in or In case of being lifted, it includes an oil return processing unit for returning the oil discharged by the second pump to the oil tank,
The oil return processing unit communicates with the ECU, while the gear is located in a forward mode or a reverse mode under a low idle condition of the engine, and the work device is tilt-in or lift When (Lift), the flow direction switching indicating valve forming a turn-on state;
In a state disposed on the oil discharge path of the second pump, it is electrically connected to the flow direction change indicating valve, and when the flow direction change indicating valve is in a turn-on state, discharged by the second pump A flow direction switching valve for changing the direction of oil and returning the oil to the oil tank;
In a state disposed on the oil discharge path of the second pump, it is electrically connected to the flow direction switching valve, and only when the pressure of the oil discharged from the second pump corresponds to a preset value, the turn-on state By achieving a pressure condition control valve that allows the flow direction switching valve to change the direction of the oil discharged by the second pump to the oil tank side only when the pressure of the oil corresponds to a preset value. Hydraulic system for a forklift, characterized in that it comprises. delete delete The method of claim 1, wherein the flow direction selector valve directs the direction of the oil discharged by the second pump toward the oil tank only when both the flow direction change indicator valve and the pressure condition control valve are in a turn-on state. Hydraulic system for a forklift, characterized in that to convert.

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