CN114673716A - A forklift energy recovery system - Google Patents

Abstract

The invention provides a forklift energy recovery system, which comprises a hydraulic driving module, a hydraulic control module and an energy recovery module, wherein the hydraulic driving module is connected with the hydraulic control module; the hydraulic driving module comprises a lifting oil cylinder group, a hydraulic power unit and a three-position six-way electromagnetic reversing valve, and the hydraulic power unit is communicated with the lifting oil cylinder group through the three-position six-way electromagnetic reversing valve; the energy recovery module comprises a recovery oil cylinder group, a two-position two-way electromagnetic reversing valve and a two-position three-way electromagnetic reversing valve; the inlet of the recovery oil cylinder group is communicated with the inlet of the three-position and six-way electromagnetic directional valve through a two-position and three-way electromagnetic directional valve; the inlet of the recovery oil cylinder group is communicated with the hydraulic power unit through a two-position two-way electromagnetic directional valve; the hydraulic control module is used for recovering energy in the load descending process by selectively controlling the connection of the three-position six-way electromagnetic reversing valve, the two-position two-way electromagnetic reversing valve and the two-position three-way electromagnetic reversing valve. The invention can effectively improve the energy utilization rate of the forklift and the service life of the hydraulic system parts.

Description

A forklift energy recovery system

technical field

The invention relates to the field of forklift trucks or the energy conversion field of hoisting equipment, in particular to a forklift truck energy recovery system.

Background technique

With the rapid development of social economy, the modern industrial logistics system has become the infrastructure to promote social development and economic construction, which is of great significance to the formation of the scale of the national economy and the development of modern industries. The type, frequency and scale of logistics in the modern industrial logistics system are increasing day by day. Therefore, the importance of loading and unloading is more significant. Forklifts are widely used in the industrial transportation industry due to their efficient handling capabilities and strong operational flexibility. various places. On the other hand, the energy crisis and the pressure of energy conservation and emission reduction are severe. The energy conservation and environmental protection cause has vigorously promoted the transformation and upgrading of forklifts, and has also put forward higher standards and requirements for the energy consumption of the hydraulic system of forklifts.

The traditional forklift hydraulic system directly releases the pressure oil to the fuel tank through the relief valve to achieve load reduction. This method causes huge energy loss and low energy utilization due to the working characteristics of the forklift truck with heavy load and frequent lifting and lowering. Therefore, it is necessary to carry out a new energy-saving design for the lifting system of the forklift, and reasonably recycle its lifting potential energy to realize the energy-saving transformation of the forklift.

The existing forklift energy recovery systems usually use hydraulic accumulators to save energy, but the technology is not mature, the energy recovery efficiency is difficult to guarantee, and the control is complicated. The accumulator equipment is huge, which affects the internal space layout of the forklift. The operation mobility of the whole vehicle is extremely unsuitable for the installation and use of small forklifts.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the present invention provides a forklift energy recovery system, which can effectively improve the energy utilization rate of the forklift and the life of the hydraulic system components, and reduce the use cost of the forklift.

The present invention achieves the above technical purpose through the following technical means.

A forklift energy recovery system, comprising a hydraulic drive module, a hydraulic control module and an energy recovery module;

The hydraulic drive module includes a lift cylinder group, a hydraulic power unit and a three-position six-way electromagnetic reversing valve, the lift cylinder group is used to lift the load, and the hydraulic power unit is connected with the three-position six-way electromagnetic reversing valve The lift cylinder group is connected to make the lift cylinder group go up and down synchronously;

The energy recovery module includes a recovery oil cylinder group, a two-position two-way electromagnetic reversing valve, and a two-position three-way electromagnetic reversing valve; the recovery oil cylinder group is used to push the slider; the inlet of the recovery oil cylinder group passes through the two-position three-way valve. The electromagnetic reversing valve is connected with the inlet of the three-position six-way electromagnetic reversing valve; the inlet of the recovery oil cylinder group is connected with the hydraulic power unit through the two-position two-way electromagnetic reversing valve;

The hydraulic control module selectively controls the engagement of the three-position six-way electromagnetic reversing valve, the two-position two-way electromagnetic reversing valve and the two-position three-way electromagnetic reversing valve, so that the outlet of the lifting cylinder group is connected to the recovery cylinder group. The inlet is connected to recover the energy of the load drop process.

Further, the hydraulic power unit includes an engine, a variable displacement hydraulic pump, a hydraulic oil tank and a second relief valve, the engine is used to drive the variable displacement hydraulic pump, and the variable displacement hydraulic pump inlet is communicated with the hydraulic oil tank, A second relief valve is installed at the outlet of the variable displacement hydraulic pump.

Further, the interfaces of the three-position six-way electromagnetic reversing valve include P port, T port, D port, A port, B port and C port, the P port and D port are respectively connected with the hydraulic power unit, the T port The port is communicated with the two-position three-way electromagnetic reversing valve, the A port and the C port are respectively communicated with the hydraulic oil tank, and the B port is communicated with the lift cylinder group.

Further, the slider is a forklift balance block.

Further, a first check valve is installed between the inlet of the recovery oil cylinder group and the two-position three-way electromagnetic reversing valve to prevent hydraulic oil from flowing from the recovery oil cylinder group to the two-position three-way electromagnetic reversing valve; the recovery oil cylinder group The first overflow valve is installed at the inlet.

Further, the hydraulic control module includes a first pressure sensor, a second pressure sensor and a console; the first pressure sensor is used to detect the working pressure of the lift cylinder group, and the second pressure sensor is used to detect the working pressure of the recovery cylinder group; The console selectively controls the engagement of the three-position six-way electromagnetic reversing valve, the two-position two-way electromagnetic reversing valve and the two-position three-way electromagnetic reversing valve according to the detection values of the first pressure sensor and the second pressure sensor .

Further, when the forklift transports the load from a high place to a low place or the forklift is unloaded, if p _r < p _m and p _{l >} p _r , the console controls the SB2 solenoid of the three-position six-way solenoid reversing valve. The coil is energized, so that the A port and the P port and the B port and the T port are respectively connected. Convert the potential energy released during the no-load descent of the load or forklift into the kinetic energy of the slider; where _pr is the detection value of the second pressure sensor; pm is the set pressure of the first relief valve, and _{p l} is the first pressure The detection value of the sensor;

When p _r = p _m or p _l ≤ p _r , the console controls the SB2 electromagnetic coil of the three-position six-way electromagnetic directional valve to be energized, so that the A port and the P port and the B port and the T port are respectively connected, so The console controls the reset of the two-position three-way electromagnetic valve to make the T port of the three-position six-way electromagnetic reversing valve communicate with the hydraulic oil tank; It is connected to the inlet of the volume hydraulic pump, which is used to lower the load or the forklift without load to the target height.

Further, when the forklift lifts the load from a low place to a high place or the forklift lifts with no load, when p _r > 0, the console controls the SB1 solenoid coil of the three-position six-way solenoid reversing valve to be energized, so that the A port is energized. It is connected with T port, B port and P port respectively. The console controls the reset of the two-position three-way solenoid valve to make the T port of the three-position six-way electromagnetic reversing valve communicate with the hydraulic oil tank, and the console controls the two-position two-way valve. The valve connects the recovery cylinder group with the variable displacement hydraulic pump inlet, and the potential energy of the slider is converted into hydraulic energy, and the engine provides auxiliary power until the load or the forklift lifts to the target height with no load; when _pr = 0, the console The SB1 solenoid coil that controls the three-position six-way solenoid valve is energized, so that the A port and the T port and the B port and the P port are respectively connected, and the console controls the two-position three-way solenoid valve to reset to make the three-position six-way solenoid switch The T port of the valve is connected to the hydraulic oil tank, which is used to lift the load or the forklift without load through the hydraulic power unit.

The beneficial effects of the present invention are:

1. The forklift energy recovery system of the present invention can alleviate the problems of high fuel consumption and high emissions of traditional forklifts, recover the potential energy of the goods and forks in the process of the forklift transporting the goods and forks from a high place to a low place, and restore the The recovered potential energy is released when the goods and forks are lifted, which improves the energy utilization efficiency of the forklift and reduces the use cost of the forklift.

2. The energy recovery system of the forklift truck according to the present invention recovers the potential energy during the descending process of the forklift load through the slider, the potential energy of the load is converted into the potential energy of the slider, the energy conversion path is short, and the energy recovery efficiency is high.

3. The energy recovery system of the forklift truck of the present invention recovers the potential energy during the load drop process through the slider, which reduces the throttling loss of the hydraulic valve compared with the traditional valve control system, avoids the excessive temperature of the hydraulic system components caused by throttling, and improves the performance of the hydraulic system. The life of the hydraulic valve is shortened, the leakage loss of the hydraulic system is reduced, and the energy recovery efficiency is further improved.

4. For the forklift energy recovery system of the present invention, sliders with different weights can be selected to meet forklifts with different load requirements, and the product coverage is wide.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. The drawings in the following description are of the present invention. In some embodiments, it is obvious to those of ordinary skill in the art that other drawings can be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic diagram of the forklift energy recovery system according to the present invention.

FIG. 2 is a schematic diagram of the load rising according to the present invention.

FIG. 3 is a schematic diagram of the load drop energy recovery according to the present invention.

FIG. 4 is a schematic diagram of the load drop according to the present invention.

FIG. 5 is a schematic diagram of the sliding block descending auxiliary load ascending principle according to the present invention.

In the picture:

1-engine; 2-speed sensor; 3-ECU; 4-variable displacement hydraulic pump; 5-three-position six-way electromagnetic reversing valve; 6-hydraulic oil tank; 7-first lift cylinder; 8-second lift Lifting cylinder; 9-first pressure sensor; 10-load; 11-console; 12-slider; 13-first recovery cylinder; 14-second recovery cylinder; 15-two-position two-way solenoid valve; 16 - The second pressure sensor; 17 - the first one-way valve; 18 - the two-position three-way electromagnetic reversing valve; 20 - the second one-way valve; 22 - the first relief valve; 23 - the second relief valve.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", The orientation or positional relationship indicated by "radial", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description , rather than indicating or implying that the indicated device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrally connected; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or the internal communication between the two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

As shown in Figure 1, the forklift energy recovery system of the present invention includes a hydraulic drive module, a hydraulic control module and an energy recovery module;

The hydraulic drive module includes a first lift cylinder 7, a second lift cylinder 8, a hydraulic power unit and a three-position six-way electromagnetic reversing valve 5. The first lift cylinder 7 and the second lift cylinder 8 are respectively installed in the At the bottom of the load 10, the hydraulic power unit includes an engine 1, a variable displacement hydraulic pump 4, a hydraulic oil tank 6 and a second relief valve 23, the engine 1 is used to drive the variable displacement hydraulic pump 4, the variable displacement The inlet of the hydraulic pump 4 communicates with the hydraulic oil tank 6 , a second check valve 20 is installed between the inlet of the variable displacement hydraulic pump 4 and the hydraulic oil tank 6 , and a second relief valve 23 is installed at the outlet of the variable displacement hydraulic pump 4 . A rotational speed sensor 2 is installed on the input shaft of the variable displacement hydraulic pump 4 for detecting the rotational speed of the variable displacement hydraulic pump 4 . The interfaces of the three-position six-way electromagnetic reversing valve 5 include P port, T port, D port, A port, B port and C port, the P port and D port are respectively connected with the hydraulic power unit, and the T port is Connected with the two-position three-way electromagnetic reversing valve 18 , the A port and the C port are respectively communicated with the hydraulic oil tank 6 , and the B port is respectively communicated with the first lift cylinder 7 and the second lift cylinder 8 . The first lift cylinder 7 and the second lift cylinder 8 can be seen as being connected in parallel between port B and the load 10 . The hydraulic power unit communicates with the first lift cylinder 7 and the second lift cylinder 8 through the three-position six-way electromagnetic reversing valve 5, so as to enable the first lift cylinder 7 and the second lift cylinder 8 to rise and fall synchronously;

The energy recovery module includes a first recovery oil cylinder 13, a second recovery oil cylinder 14, a two-position two-way electromagnetic reversing valve 15, and a two-position three-way electromagnetic reversing valve 18; the first recovery oil cylinder 13 and the second recovery oil cylinder 14 is used to push the slider 12 to lift at the same time, and the slider 12 is a forklift balance block; the inlets of the first recovery cylinder 13 and the second recovery cylinder 14 pass through the two-position three-way electromagnetic reversing valve 18 and the three-position six-way The T port of the electromagnetic reversing valve 5 is communicated; the inlets of the first recovery oil cylinder 13 and the second recovery oil cylinder 14 are communicated with the inlet of the variable displacement hydraulic pump 4 through the two-position two-way electromagnetic reversing valve 15; the first recovery A first check valve 17 is installed between the inlets of the oil cylinder 13 and the second recovery oil cylinder 14 and the two-position three-way electromagnetic reversing valve 18 to prevent hydraulic oil from flowing from the first recovery oil cylinder 13 and the second recovery oil cylinder 14 to the A two-position three-way electromagnetic reversing valve 18 ; a first relief valve 22 is installed at the inlets of the first recovery cylinder 13 and the second recovery cylinder 14 .

The hydraulic control module includes a first pressure sensor 9, a second pressure sensor 16, an ECU 3 and a console 11; the first pressure sensor 9 is used to detect the working pressure of the lift cylinder groups 7 and 8, and the second pressure sensor 16 It is used to detect the working pressure of the recovery cylinder groups 13 and 14; the console 11 selectively controls the three-position six-way electromagnetic reversing valve 5 and the two-position two-position valve according to the detection values of the first pressure sensor 9 and the second pressure sensor 16. The coupling of the electromagnetic reversing valve 15 and the two-position three-way electromagnetic reversing valve 18 makes the outlet of the lift cylinder group communicate with the inlet of the recovery cylinder group, which is used to recover the energy of the load 10 during the descending process. The ECU 3 is used to control the engine 1 , and the console 11 issues commands to the ECU 3 .

The following is a detailed description of the operation mode of the forklift potential energy recovery system by analyzing four typical operating conditions from the forklift load drop, no-load drop, load rise, and no-load rise as examples. The examples are used to further illustrate the present invention. It is understood that it is a limitation on the protection scope of the present invention, and some non-essential improvements and adjustments made by those skilled in the art according to the above-mentioned contents of the present invention also belong to the protection scope of the present invention.

As shown in FIG. 3 , when the forklift transports the load from a high place to a low place or the forklift is unloaded, if p _r < p _m and p _{l >} p _r , the console 11 controls the three-position six-way electromagnetic switch. The SB2 solenoid coil of the valve 5 is energized, so that the A port and the P port and the B port and the T port are respectively connected. The console 11 controls the two-position three-way solenoid valve 18 to make the T The port is communicated with the first recovery cylinder 13 and the second recovery cylinder 14, and is used to convert the potential energy released during the load 10 or the forklift's no-load descending process into the kinetic energy of the slider 12; where _pr is the detection of the second pressure sensor 16 p _m is the set pressure of the first relief valve 22, p _l is the detection value of the first pressure sensor 9; when p _r = p _m or p _l ≤ p _r , the console 11 controls three six The SB2 electromagnetic coil of the electromagnetic reversing valve 5 is energized, so that the A port and the P port and the B port and the T port are respectively connected. The T port of the valve 5 is communicated with the hydraulic oil tank 6 for lowering the load 10 or the forklift without load to the target height, as shown in FIG. 4 .

As shown in FIG. 2 , when the forklift lifts the load from a low place to a high place or the forklift lifts with no load, when p _r >0, the console 11 controls the SB1 solenoid coil of the three-position six-way solenoid directional valve 5 When the power is turned on, the A port is connected with the T port and the B port with the P port respectively. The console 11 controls the two-position three-way solenoid valve 18 to reset, so that the T port of the three-position six-way electromagnetic reversing valve 5 is communicated with the hydraulic oil tank 6 , the console 11 controls the two-position two-way valve 15 to make the first recovery cylinder 13 and the second recovery cylinder 14 communicate with the inlet of the variable displacement hydraulic pump 4, and the potential energy of the slider 12 is converted into hydraulic energy, and the engine 1 provides assistance power until the load 10 or the forklift lifts the target height with no load; when _pr = 0, the console 11 controls the SB1 solenoid coil of the three-position six-way solenoid valve 5 to be energized, so that the A port and the T port and the B port are energized. The port is connected with the P port respectively, the console 11 controls the reset of the two-position three-way solenoid valve 18 to make the T port of the three-position six-way electromagnetic reversing valve 5 communicate with the hydraulic oil tank 6, and is used to make the load 10 or 10 through the hydraulic power unit. The forklift goes up with no load, as shown in Figure 5.

It should be understood that although this specification is described according to various embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Changes should all be included within the protection scope of the present invention.

Claims (8)

1. a forklift energy recovery system, is characterized in that, comprises hydraulic drive module, hydraulic control module and energy recovery module; The hydraulic drive module includes a lift cylinder group (7, 8), a hydraulic power unit and a three-position six-way electromagnetic reversing valve (5), and the lift cylinder group (7, 8) is used for lifting and lowering the load (10). ), the hydraulic power unit communicates with the lift cylinder group (7, 8) through a three-position six-way electromagnetic reversing valve (5), so as to make the lift cylinder group (7, 8) rise and fall synchronously; The energy recovery module includes a recovery oil cylinder group (13, 14), a two-position two-way electromagnetic reversing valve (15), and a two-position three-way electromagnetic reversing valve (18); the recovery oil cylinder group (13, 14) uses to push the slider (12); the inlet of the recovery cylinder group (13, 14) communicates with the inlet of the three-position, six-way solenoid valve (5) through the two-position three-way electromagnetic reversing valve (18); the recovery The inlet of the oil cylinder group (13, 14) is communicated with the hydraulic power unit through the two-position two-way electromagnetic reversing valve (15); The hydraulic control module selectively controls the engagement of the three-position six-way electromagnetic reversing valve (5), the two-position two-way electromagnetic reversing valve (15), and the two-position three-way electromagnetic reversing valve (18), so that the lift is carried out. The outlet of the lift cylinder group (7, 8) is communicated with the inlet of the recovery cylinder group (13, 14) for recovering the energy of the load (10) descending process. 2. The forklift energy recovery system according to claim 1, wherein the hydraulic power unit comprises an engine (1), a variable displacement hydraulic pump (4), a hydraulic oil tank (6) and a second relief valve ( 23), the engine (1) is used to drive the variable displacement hydraulic pump (4), the inlet of the variable displacement hydraulic pump (4) is communicated with the hydraulic oil tank (6), and the variable displacement hydraulic pump (4) A second relief valve (23) is installed at the outlet. 3. The forklift energy recovery system according to claim 1, characterized in that the interfaces of the three-position six-way electromagnetic reversing valve (5) include P port, T port, D port, A port, B port and C port The P port and the D port are respectively communicated with the hydraulic power unit, the T port is communicated with the two-position three-way electromagnetic reversing valve (18), the A port and the C port are respectively communicated with the hydraulic oil tank (6), The B port is communicated with the lift cylinder group (7, 8). 4. The forklift energy recovery system according to claim 1, wherein the slider (12) is a forklift balance block. 5 . The forklift energy recovery system according to claim 1 , wherein a first check valve ( 17), for preventing hydraulic oil from flowing from the recovery cylinder group (13, 14) to the two-position three-way electromagnetic reversing valve (18); a first relief valve (22) is installed at the inlet of the recovery cylinder group (13, 14) . 6. The forklift energy recovery system according to claim 3, wherein the hydraulic control module comprises a first pressure sensor (9), a second pressure sensor (16) and a console (11); the first pressure sensor (9) is used to detect the working pressure of the lift cylinder group (7, 8), the second pressure sensor (16) is used to detect the working pressure of the recovery cylinder group (13, 14); the console (11) The detected values of a pressure sensor (9) and a second pressure sensor (16) selectively control the three-position six-way electromagnetic reversing valve (5), the two-position two-way electromagnetic reversing valve (15) and the two-position three-way Engagement of solenoid reversing valve (18). 7. The forklift energy recovery system according to claim 6, wherein when the forklift transports the load from a high place to a low place or the forklift is no-loaded, if p _r < p _m and p _{l >} p _r , The console (11) controls the SB2 solenoid coil of the three-position six-way electromagnetic reversing valve (5) to be energized, so that the A port and the P port and the B port and the T port are respectively connected, and the console (11) controls the two The three-position solenoid valve (18) communicates the T port of the three-position six-way solenoid reversing valve (5) with the recovery oil cylinder group (13, 14), and is used to release the load (10) or the forklift during the no-load lowering process. The potential energy is converted into the kinetic energy of the slider (12); wherein, p _r is the detection value of the second pressure sensor (16); p _m is the set pressure of the first relief valve (22), and p _l is the first pressure sensor ( 9) detection value; When p _r = p _m or p _l ≤ p _r , the console (11) controls the SB2 solenoid coil of the three-position, six-way solenoid reversing valve (5) to be energized, so that the A port is connected to the P port and the B port is connected to each other. The T ports are respectively connected, and the console (11) controls the reset of the two-position three-way solenoid valve (18) to make the T port of the three-position six-way solenoid reversing valve (5) communicate with the hydraulic oil tank (6). (11) Control the two-position two-way electromagnetic reversing valve (15) to connect the inlet of the recovery cylinder group (13, 14) with the inlet of the variable displacement hydraulic pump (4), which is used to lower the load (10) or the forklift without load to target height. 8. The forklift energy recovery system according to claim 7, characterized in that when the forklift lifts the load from a low place to a high place or the forklift lifts with no load, when p _r >0, the console (11) The SB1 solenoid coil that controls the three-position six-way solenoid directional valve (5) is energized, so that the A port and the T port and the B port and the P port are respectively connected, and the console (11) controls the two-position three-way solenoid valve (18). ) reset to make the T port of the three-position six-way electromagnetic reversing valve (5) communicate with the hydraulic oil tank (6), and the console (11) controls the two-position two-way valve (15) to recover the oil cylinder group (13, 14) Connected with the inlet of the variable displacement hydraulic pump (4), the potential energy of the slider (12) is converted into hydraulic energy, and the engine (1) provides auxiliary power until the load (10) or the forklift lifts to the target height with no load; when _pr = At 0, the console (11) controls the SB1 solenoid coil of the three-position six-way electromagnetic reversing valve (5) to be energized, so that the A port and the T port and the B port and the P port are respectively connected, and the console (11) ) control the reset of the two-position three-way solenoid valve (18) so that the T port of the three-position six-way solenoid reversing valve (5) is connected to the hydraulic oil tank (6), which is used to make the load (10) or the forklift unloaded through the hydraulic power unit rise.

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