CN110307200B - Forklift tilt control system and method - Google Patents
Forklift tilt control system and method Download PDFInfo
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- CN110307200B CN110307200B CN201810534263.9A CN201810534263A CN110307200B CN 110307200 B CN110307200 B CN 110307200B CN 201810534263 A CN201810534263 A CN 201810534263A CN 110307200 B CN110307200 B CN 110307200B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
- B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
- B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
- B66F9/075—Constructional features or details
- B66F9/20—Means for actuating or controlling masts, platforms, or forks
- B66F9/22—Hydraulic devices or systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/22—Synchronisation of the movement of two or more servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K11/00—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves
- F16K11/02—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit
- F16K11/06—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements
- F16K11/065—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members
- F16K11/07—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members with cylindrical slides
- F16K11/0708—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members with cylindrical slides comprising means to avoid jamming of the slide or means to modify the flow
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K11/00—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves
- F16K11/02—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit
- F16K11/06—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements
- F16K11/065—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members
- F16K11/07—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members with cylindrical slides
- F16K11/0716—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with all movable sealing faces moving as one unit comprising only sliding valves, i.e. sliding closure elements with linearly sliding closure members with cylindrical slides with fluid passages through the valve member
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K47/00—Means in valves for absorbing fluid energy
- F16K47/04—Means in valves for absorbing fluid energy for decreasing pressure or noise level, the throttle being incorporated in the closure member
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Structural Engineering (AREA)
- Fluid Mechanics (AREA)
- Transportation (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Civil Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Forklifts And Lifting Vehicles (AREA)
Abstract
A forklift tilt control system and method comprises a control valve, a tilt cylinder group, a hydraulic oil pump and an oil tank; the control valve is provided with a valve rod and a valve body, the valve body is provided with an oil inlet cavity, an oil outlet cavity, a first oil port and a second oil port, the oil inlet cavity is communicated with a hydraulic oil pump, the first oil port and the second oil port are respectively communicated with a rod cavity and a rodless cavity of an inclined oil cylinder group, the oil outlet cavity is communicated with an oil tank, and the valve rod is arranged in the valve body in a penetrating way and is provided with an oil passing groove; the valve rod is also provided with a throttling groove which is communicated in the radial direction, the valve rod can be controlled to move leftwards so that the oil passing groove is communicated with the first oil port and the oil inlet cavity, the throttling groove is communicated with the second oil port and the oil outlet cavity, and the flow area of the throttling groove is linearly changed relative to the backward tilting speed. The invention can realize the linear control of the retroversion speed and limit the maximum retroversion speed, and the retroversion process has no noise.
Description
Technical Field
The invention relates to a forklift, in particular to a forklift tilt control system and a forklift tilt control method.
Background art
Fig. 1 and 2 are hydraulic schematic diagrams of a conventional forklift tilt, which mainly include a control valve, a tilt cylinder, a hydraulic oil pump, a hydraulic oil tank, and the like. The control valve includes a valve stem and a valve body.
The valve body comprises a plurality of oil ports and a cavity, and the valve rod is provided with an oil passing groove, a plurality of oil passing holes and the like. The hydraulic pump provides an oil source to the cavity P, and hydraulic oil in the cavity T returns to the hydraulic oil tank. The oil port A is connected with a rod cavity of the inclined oil cylinder through a pipeline and a joint F. The oil port B is connected with the rodless cavity of the inclined oil cylinder through a pipeline and a connector E. The two inclined oil cylinders are respectively connected with the vehicle body and the portal frame, rodless cavities of the two inclined oil cylinders are communicated through a pipeline, and rod cavities are communicated through a pipeline.
The valve rod is connected with a vehicle operating lever, and the forward and backward tilting actions are realized through the left and right movement of the valve rod. When the control valve rod moves left and right, the cavity P is communicated with the oil port B and the cavity T is communicated with the oil port A, or the cavity P is communicated with the oil port A and the cavity T is communicated with the oil port B; when pressure oil of the oil port B enters the rodless cavity of the inclined oil cylinder, the piston rod is pushed out to realize forward tilting action, and the pressure oil of the rod cavity is sent into the cavity T through the oil port A and the valve rod. When pressure oil of the oil port A enters the rod cavity, the piston rod retracts to realize backward tilting action, and the pressure oil of the rodless cavity is sent into the cavity T through the oil port B and the valve rod.
At present, a damping joint is arranged at an oil port B of a control valve, and the maximum backward tilting speed is controlled through a throttling hole arranged in the damping joint.
Disclosure of Invention
The main purpose of the present invention is to overcome the above mentioned drawbacks in the prior art, and to provide a forklift tilt control system and method that can linearly relate the backward tilting speed to the valve stem flow area, and does not need to add extra components, and is low in cost.
The invention adopts the following technical scheme:
a forklift tilt control system comprises a control valve, a tilt cylinder group, a hydraulic oil pump and an oil tank; the control valve is provided with a valve rod and a valve body, the valve body is provided with an oil inlet cavity, an oil outlet cavity, a first oil port and a second oil port, the oil inlet cavity is communicated with a hydraulic oil pump, the first oil port and the second oil port are respectively communicated with a rod cavity and a rodless cavity of an inclined oil cylinder group, the oil outlet cavity is communicated with an oil tank, and the valve rod is arranged in the valve body in a penetrating way and is provided with an oil passing groove; the method is characterized in that: the valve rod is also provided with a throttling groove which is communicated in the radial direction, the valve rod can be controlled to move leftwards so that the oil passing groove is communicated with the first oil port and the oil inlet cavity, the throttling groove is communicated with the second oil port and the oil outlet cavity, and the flow area of the throttling groove is linearly changed relative to the backward tilting speed.
Preferably, the throttle groove comprises at least one U-shaped groove.
Preferably, the throttle groove comprises two U-shaped grooves.
Preferably, the throttling groove comprises at least one triangular groove.
Preferably, the throttling groove comprises at least one trapezoidal groove.
Preferably, the throttle groove comprises at least one L-shaped groove.
Preferably, the throttle groove extends in the axial direction.
A forklift tilt control method is characterized by comprising the following steps: the valve rod of the control valve is provided with a throttling groove which is radially communicated, when the control valve is inclined backwards, the valve rod moves to drive hydraulic oil in the oil inlet cavity to enter the rod cavity of the inclined oil cylinder group through the first oil port so as to realize the backward inclining action, hydraulic oil in the rodless cavity enters the oil outlet cavity through the second oil port and the throttling groove and returns to the oil tank, and in the backward inclining process, the flow area of the throttling groove is linearly changed relative to the backward inclining speed
Preferably, the flow area is related to the length, width and depth of the throttling groove.
Preferably, the linear relationship between the flow area of the throttling groove and the backward tilting speed of the forklift is as follows:
q is target flow and is converted according to the target retroversion speed; cdIs the flow coefficient; a is the flow area; delta p is the pressure difference between the second oil port and the oil outlet cavity; ρ is the hydraulic oil density.
As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:
1. the system and the method of the invention are characterized in that the valve rod is provided with the throttling groove which is through in the radial direction, the overflowing area of the throttling groove is linearly changed relative to the backward tilting speed, so that the backward tilting speed is linearly controlled, the backward tilting maximum speed is limited, and the backward tilting process is noiseless.
2. The throttling grooves of the present invention can take various forms including U-shaped grooves, triangular grooves, trapezoidal grooves, L-shaped grooves, etc., the number and relative size being determined by the flow area.
3. The throttling groove of the invention can replace the prior overflowing groove, does not generate extra cost and working hours, and reduces the cost.
Drawings
FIG. 1 is a schematic diagram of a prior art forklift tilt control;
FIG. 2 is a schematic diagram of a prior art tilt control;
FIG. 3 is a cross-sectional view of the structure of the present invention (reclined);
FIG. 4 is a cross-sectional view of the present invention (neutral position);
FIG. 5 is an enlarged view of a portion of FIG. 3;
FIG. 6 is a cross-sectional view (forward tilted) of the inventive structure;
FIG. 7 is an enlarged view of a portion of FIG. 6;
FIG. 8 is a schematic view of a triangular groove;
FIG. 9 is a schematic view of a dovetail groove;
FIG. 10 is a schematic view of an L-shaped slot;
FIG. 11 is a linear plot of the area of flow versus the speed of recline;
FIG. 12 is a graph of stem displacement versus recline speed for the present invention;
wherein: 10. the hydraulic oil pump comprises a valve rod 11, an oil passing groove 12, an inclined hole 13, an oil passing hole 14, a movable rod 15, an elastic piece 16, a piston part 17, a through hole 19, a throttling groove 20, a valve body 21, an oil inlet cavity 22, an oil outlet cavity 23, a first oil port 24, a second oil port 30, an inclined oil cylinder group 31, a rod cavity 32, a rodless cavity 40, a hydraulic oil pump 50 and an oil tank.
Detailed Description
The invention is further described below by means of specific embodiments.
Referring to fig. 3 to 6, a forklift backward tilting control system includes a control valve, a tilting cylinder group 30, a hydraulic oil pump 40, an oil tank 50, and the like. The control valve is provided with a valve rod 10 and a valve body 20, and the valve body 20 is provided with an oil inlet chamber 21, an oil outlet chamber 22, a first oil port 23 and a second oil port 24. The oil inlet chamber 21 communicates with a hydraulic oil pump 40, and hydraulic oil is pumped to the oil inlet chamber 21 by the hydraulic oil pump 40. The first oil port 23 and the second oil port 24 are respectively communicated with a rod cavity 31 and a rodless cavity 32 of the inclined oil cylinder group 30, the inclined oil cylinder group 30 comprises two inclined oil cylinders, the rodless cavities 32 of the two inclined oil cylinders are communicated through oil pipes, and the two rod cavities 31 are communicated through the oil pipes. The oil outlet chamber 22 communicates with the oil tank 50 for sending hydraulic oil to the oil tank 50.
This valve rod 10 wears to locate in valve body 20, and valve rod 10 one end is equipped with well cavity, and this end is equipped with oil groove 11, crosses 11 both sides in oil groove and is equipped with inclined hole 12 respectively, crosses and is equipped with oil hole 13 on the oil groove 11. The hollow cavity is internally provided with a one-way valve component which comprises a movable rod 14 and an elastic part 15, the movable rod 14 is a hollow movable rod, two piston parts 16 which are distributed at intervals are arranged on the periphery of the hollow movable rod, and a through hole 17 is formed between the two piston parts 16. The resilient member 15 bears between the end of the movable rod 14 and the corresponding end of the valve stem 10.
The valve stem 10 is provided with a throttling groove 19 near the other end. The throttle groove 19 extends in the axial direction and penetrates in the radial direction. The throttling groove 19 may comprise at least one U-shaped groove, and the slotted hole is preferably formed by symmetrically arranging two U-shaped grooves. The valve stem 10 is connected to the operating lever of a forklift truck, and when the operating lever is operated to tilt backward or forward, the valve stem 10 can move leftward or rightward in a radial direction from the neutral position.
The invention also provides a forklift tilt control method, wherein a valve rod 10 of a control valve is provided with a throttle groove 19 which is through in the radial direction, when the control valve tilts backwards, hydraulic oil in an oil inlet cavity 21 enters a rod cavity 31 of a tilt cylinder group 30 through a first oil port 23 to realize backward tilting action, hydraulic oil in a rodless cavity 32 enters an oil outlet cavity 22 through a second oil port 24 and the throttle groove 19 and returns to an oil tank 50, and the flow area of the throttle groove 19 changes linearly relative to the backward tilting speed in the backward tilting process. The specific working principle is as follows:
referring to fig. 4, in a normal state, the valve rod 10 is in a neutral position, and the throttling groove 19 is communicated with the second oil port 24 and is not communicated with the oil outlet chamber 22 and the oil inlet chamber 21. The oil passing groove 11 and the oil passing hole 13 are communicated with the first oil port 23 and the through hole 17 of the movable rod 14, and are not communicated with the oil outlet chamber 22 and the oil inlet chamber 21.
Referring to fig. 3, when the operating lever is operated to tilt backwards, the valve rod 10 moves leftwards, the oil passing groove 11 is communicated with the first oil port 23 and the oil inlet cavity 21, and the throttling groove 19 is communicated with the second oil port 24 and the oil outlet cavity 22. The hydraulic oil in the oil inlet cavity 21 enters the rod cavity 31 of the tilt cylinder through the first oil port 23, the piston rod retracts to realize backward tilting action, and the hydraulic oil in the rodless cavity 32 enters the oil outlet cavity 22 through the second oil port 24 and the throttling groove 19 and returns to the oil tank 50. During the backward tilting, see fig. 11, the flow area (i.e. the opening area, which affects the change of the hydraulic oil flow rate on both sides) of the throttle groove 19 changes linearly with respect to the backward tilting speed, and when reaching the leftmost side, the flow area reaches the maximum and the backward tilting speed also reaches the maximum. The flow area of the throttling groove 19 is linearly related to the backward tilting speed of the forklift as follows:
q is target flow and is converted according to the target retroversion speed; cdFor the flow coefficient, e.g. 0.6-0.9, C may be takendOther values can be taken as 0.7, and the values are determined according to corresponding formulas and historical empirical data of the structural valve; a is the flow area; Δ p is a pressure difference between the second port 24 and the oil outlet cavity 22, and Δ p ═ pB-pT pBTaking the maximum pressure value, p, of the large cavity (i.e. rodless cavity) of the backward-tilting tilt cylinderTTaking a value according to the actual pressed condition of the system, and taking 0 by the system; ρ is the hydraulic oil density, obtained from the hydraulic oil manufacturer. Referring to fig. 6 and 7, when the operating lever is operated to tilt forward, the valve rod 10 moves from the right direction, the throttling groove 19 communicates with the second oil port 24 and the oil inlet cavity 21, the inclined holes 12 on the two sides of the valve rod 10 communicate with the oil inlet cavity 21 and the oil outlet cavity 22 respectively, and hydraulic oil in the valve rod 10 pushes the piston rod, so that the oil passing hole 13 communicates with the oil passing groove 11 and the inclined hole 12 on the right side. The hydraulic oil in the oil inlet cavity 21 enters the rodless cavity 32 of the tilting cylinder through the second oil port 24 to push the piston rod to extend forwards to realize forward tilting, and the hydraulic oil in the rod cavity 31 enters the oil outlet cavity 22 through the first oil port 23, the oil passing groove 11, the oil passing hole 13 and the inclined hole 12 and returns to the oil tank 50.
In the present invention, the flow area is related to the length, width and depth of the throttle groove 19. The shape of the throttle groove 19 is not limited, and may include a triangular groove, a trapezoidal groove, an L-shaped groove, and the like, and the number of grooves (triangular groove, trapezoidal groove, L-shaped groove) included in the throttle groove 19 is determined by the flow area, as shown in fig. 8 to 10.
On the basis of the known target retroversion speed, the flow area A needs to be obtained, so the formula is transformed into
Q can be derived from the maximum recline speed required by the system. The basic formula is as follows
Q＝2*v*S。
Wherein 2 represents two tilt cylinders; v represents the target recline speed and S represents the tilt cylinder gallery area (i.e., the rodless gallery), and the target flow area a of the throttle slot 19 is calculated from the above equation.
The throttling groove of the valve stem 10 is designed according to the target flow area a of the valve stem. Taking the U-shaped throttling groove as an example, the cross section area of the U-shaped groove is approximately taken as the valve rod flow area through simplification. (also based on three-dimensional graphical measurements, or other more elaborate formulas). The number of U-shaped grooves is preferably 2-4 according to historical experience. The throttle slot length L' is determined by the valve stem 10 design stroke.
According to the number of different U-shaped grooves, different rodless cavity areas S and different U-shaped groove flow areas (r, depth), experimental design analysis is carried out:
the experimental protocol was designed as follows:
| plan numbering | Number of U-shaped grooves | Flow area of U-shaped groove | Maximum Tilt speed-obtained by experiment |
| 1 | 2 | S1-r1,depth 1 | Vmax1 |
| 2 | 2 | S2-r2,depth 2 | Vmax2 |
| 3 | 3 | S3-r3,depth 3 | Vmax3 |
| 4 | 3 | S4-r4,depth 4 | Vmax4 |
| 5 | 4 | S5-r5,depth 5 | Vmax5 |
| 6 | 4 | S6-r6,depth 6 | Vmax6 |
The results of the retroversion speed test under different U-shaped groove numbers and sizes are obtained. We know that the number of U-shaped slots has a significant impact on the experimental results.
We select 2U-shaped grooves, and design different U-shaped groove areas (r, depth) for further experimental optimization analysis.
| Plan numbering | Number of U-shaped grooves | Flow area of U-shaped groove | Maximum Tilt speed-obtained by experiment |
| 1 | 2 | S7-r7,depth 7 | Vmax7 |
| 2 | 2 | S8-r8,depth 8 | Vmax8 |
| 3 | 2 | S9-r9,depth 9 | Vmax9 |
| 4 | 2 | S10-r10, |
Vmax10 |
Finally, we obtain the optimal parameter configuration. For example, for this kind of combined valve, the number of U-shaped throttling grooves is 2, see fig. 5, r is 1.5mm, depth is 1.5mm, and L' is 15 mm. After the throttling groove is designed, a relationship diagram of the displacement of the valve rod 10 and the backward tilting speed can be obtained, and the relationship diagram is shown in fig. 12.
Claims (9)
1. A forklift tilt control system comprises a control valve, a tilt cylinder group, a hydraulic oil pump and an oil tank; the control valve is provided with a valve rod and a valve body, the valve body is provided with an oil inlet cavity, an oil outlet cavity, a first oil port and a second oil port, the oil inlet cavity is communicated with a hydraulic oil pump, the first oil port and the second oil port are respectively communicated with a rod cavity and a rodless cavity of an inclined oil cylinder group, the oil outlet cavity is communicated with an oil tank, and the valve rod is arranged in the valve body in a penetrating way and is provided with an oil passing groove; the method is characterized in that: the valve rod is also provided with a throttling groove which is communicated in the radial direction, the valve rod can be controlled to move so that the oil passing groove is communicated with the first oil port and the oil inlet cavity, the throttling groove is communicated with the second oil port and the oil outlet cavity, the flow area of the throttling groove is linearly changed relative to the backward tilting speed, the backward tilting speed is also maximized when the flow area is maximized, and the relationship is as follows
Q is target flow and is converted according to the target retroversion speed; cdIs the flow coefficient; a is the flow area; delta p is the pressure difference between the second oil port and the oil outlet cavity; ρ is the hydraulic oil density.
2. The forklift tilt control system of claim 1, wherein: the throttling groove comprises at least one U-shaped groove.
3. The forklift tilt control system of claim 1, wherein: the throttling groove comprises two U-shaped grooves.
4. The forklift tilt control system of claim 1, wherein: the throttling groove comprises at least one triangular groove.
5. The forklift tilt control system of claim 1, wherein: the throttling groove comprises at least one trapezoidal groove.
6. The forklift tilt control system of claim 1, wherein: the throttling groove comprises at least one L-shaped groove.
7. The forklift tilt control system of claim 1, wherein: the throttling groove extends along the axial direction.
8. A forklift tilt control method is characterized by comprising the following steps: the system as claimed in any one of claims 1 to 7, wherein a throttle slot is radially disposed through a valve rod of the control valve, when the control valve is tilted backwards, the valve rod moves to drive hydraulic oil in the oil inlet chamber to enter a rod chamber of the tilting cylinder set through a first oil port to realize the backward tilting action, hydraulic oil in the rodless chamber enters an oil outlet chamber through a second oil port and the throttle slot to return to the oil tank, during the backward tilting, an area of the throttle slot changes linearly with respect to a backward tilting speed, and when the area of the throttle slot reaches a maximum value, the backward tilting speed also reaches a maximum value, and the relationship is as follows:
q is target flow and is converted according to the target retroversion speed; cdIs the flow coefficient; a is the flow area; delta p is the pressure difference between the second oil port and the oil outlet cavity; ρ is the hydraulic oil density.
9. The tilt control method for a forklift according to claim 8, wherein: the flow area is related to the length, width and depth of the throttling groove.
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| CN114294284B (en) * | 2021-12-26 | 2024-04-09 | 浙江海宏液压科技股份有限公司 | Working valve plate and electrohydraulic proportional multi-way valve |
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| CN201254447Y (en) * | 2008-05-21 | 2009-06-10 | 温跃清 | Forklifts multi-way valve with outlay type inclined lock |
| CN203685741U (en) * | 2014-01-20 | 2014-07-02 | 浙江高宇液压机电有限公司 | Multi-path reversing valve with oil return regeneration function |
| CN104141650A (en) * | 2014-07-29 | 2014-11-12 | 浙江海宏液压科技股份有限公司 | Load sensitive forklift multi-way valve |
| CN104373402A (en) * | 2014-11-14 | 2015-02-25 | 江苏柳工机械有限公司 | Valve element of hydraulic multi-way valve |
| CN104632743A (en) * | 2015-02-04 | 2015-05-20 | 阜新捷力液压科技有限公司 | Bidirectional tilting self-locking multi-way valve |
| CN205064924U (en) * | 2015-09-25 | 2016-03-02 | 比亚迪股份有限公司 | Control valve, multiple unit valve and fork truck |
| CN105840575A (en) * | 2015-12-30 | 2016-08-10 | 中船重工重庆液压机电有限公司 | Slowly open-close electro-hydraulic directional valve |
| CN105822618A (en) * | 2016-05-22 | 2016-08-03 | 浙江海宏液压科技股份有限公司 | Lifting valve plate of electric-hydraulic proportional multi-way valve of forklift |
| CN205779967U (en) * | 2016-05-22 | 2016-12-07 | 浙江海宏液压科技股份有限公司 | A kind of self-locking structure that leaning forward of forklift multi-way valve |
| CN107244640A (en) * | 2017-05-31 | 2017-10-13 | 安徽合力股份有限公司 | A kind of heavy forklift dump ram buffer control system and its control method |
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