WO2011116702A1

WO2011116702A1 - Tandem hydraulic cylinders and stroke control device and method thereof

Info

Publication number: WO2011116702A1
Application number: PCT/CN2011/072126
Authority: WO
Inventors: 高荣芝; 李沛林
Original assignee: 长沙中联重工科技发展股份有限公司; 湖南中联重科专用车有限责任公司
Priority date: 2010-03-24
Filing date: 2011-03-24
Publication date: 2011-09-29
Also published as: CN101776107B; CN101776107A

Abstract

Disclosed are tandem hydraulic cylinders and a stroke control device and a method thereof. The tandem hydraulic cylinders comprise a first hydraulic cylinder (12) having a piston rod (125) which is capable of moving reciprocatively and at least one direction switch signal generator (16) used for providing direction switch signal for the piston rod, a second hydraulic cylinder (14) having a piston rod (145) which is capable of moving reciprocatively and at least one direction switch signal generator (17) used for providing direction switch signal for the piston rod. The rod end chamber (121) of the first hydraulic cylinder and the rod end chamber (141) of the second hydraulic cylinder are communicated with each other to form a communicating chamber, or the rodless chamber (123) of the first hydraulic cylinder and the rodless chamber (143) of the second hydraulic cylinder are communicated with each other to form a communicating chamber. The tandem hydraulic cylinders further comprise two stroke position collectors (18, 19) which are disposed staggeredly in the longitudinal direction of the tandem hydraulic cylinders to form a control area of the hydraulic cylinder stroke. It can more accurately control the position of the piston rod of the hydraulic cylinder by controlling the hydraulic cylinder in the control area and regulating the oil volume of the communicating chamber in real time and continuously.

Description

Series hydraulic cylinder and stroke control device and method thereof

Technical field

The present invention relates to a tandem hydraulic cylinder applied to a concrete pump or the like, a stroke control method thereof, and a stroke control device using the same. Background technique

Equipment such as concrete pumps typically achieve continuous pumping of concrete through the reciprocating motion of two series hydraulic cylinders. The two series hydraulic cylinders have the same cylinder diameter and rod diameter, and can theoretically maintain synchronous motion.

However, due to manufacturing precision, load, leakage, etc., the two hydraulic cylinders of a pair of series hydraulic cylinders are not synchronized. As time passes, the synchronization error gradually increases. If there is no control device, it will increase to the system. normal work.

A pressure relief type damping mechanism is commonly used on concrete pumps to adjust the stroke of the series hydraulic cylinders. As shown in FIG. 1, the rodless chamber 123 of the first hydraulic cylinder 12 of the series hydraulic cylinder and the rodless chamber 143 of the second hydraulic cylinder 14 are connected together to form a communication chamber, and the rod chamber 121 and the second chamber of the first hydraulic cylinder The rod chamber 141 of the hydraulic cylinder 14 is an oil inlet chamber. When the rod chamber 121 enters the oil, the piston rod 125 retreats and the piston rod 145 extends. When the rod chamber 141 enters the oil, the piston rod 145 retreats, and the piston rod 121 Extend. The first hydraulic cylinder 12 is provided with a pressure relief type buffer mechanism 127, and the second hydraulic cylinder 14 is provided with a pressure relief type buffer mechanism 147. The stroke of the first hydraulic cylinder 12 is equal to the stroke of the second hydraulic cylinder 12, and is also the stroke of the series hydraulic cylinder, that is, the hydraulic cylinder stroke.

However, the pressure relief type buffer mechanism needs to be perforated in the hydraulic cylinder, so its position cannot be flexibly adjusted, and the hydraulic cylinder buffer distance is different depending on the pressure, flow rate, bore diameter, rod diameter, and commutation control system, so it is difficult to adapt. In complex conditions, sometimes the stroke is shortened or the stroke becomes longer, resulting in insufficient lubrication or poor suction, which will have a great impact on the wear characteristics and efficiency of the pumping system.

Patent document WO1990004104A1 discloses a control stroke mode of a series hydraulic cylinder, as shown in FIG. 2, the two delivery cylinders are respectively push-pull operated by driving the hydraulic cylinder with alternating compression and suction strokes, wherein the rodless cavity Port A and B are mutually inlet and outlet, and the rod cavity is connected to become the Unicom chamber. The three-way four-way solenoid valve controls the replenishing or draining oil. The port P is the replenishing port. Port T is the return port. That is, the pressurized oil is alternately supplied to the piston cover end of the driving hydraulic cylinder, and the driving sides of the two rod ends are connected to each other, and the piston stroke can be balanced by the supply and discharge of the hydraulic oil, wherein the logical connection of each other is final. Signal (by sensor Bl, B2, B3, B4 detection) Trigger on the four end positions of the hydraulic cylinder piston rod.

When the rod end signal of one piston rod is already present, and the end end signal of the other piston rod is not present, the hydraulic fluid is supplied, and when the rod end end signal of a piston rod does not exist, When the end position signal of the other end of the piston rod is present, the hydraulic fluid is discharged; and when the rod end and the end end signal of the two piston rods are present or absent, the supply and discharge of the hydraulic oil will be stopped. .

For example, referring to FIG. 2, when the sensor B1 detects the rod end signal and the B4 does not detect the end end signal, the hydraulic oil needs to be supplied; when the sensor B1 does not detect the rod end signal When B4 detects the end position signal of the cover end, it needs to discharge the hydraulic oil; when the sensor B1 detects the end position signal of the rod end and B4 detects the end position signal of the cover end, and when the sensor B1 does not detect the end of the rod end When the bit signal and B4 do not detect the cap end signal, the supply and discharge of the hydraulic fluid are stopped.

According to this technical solution, whether it is necessary to supply hydraulic fluid or discharge hydraulic fluid, it is necessary to stop the operation of the series hydraulic cylinder to wait for the response piston rod to be in place.

Therefore, the program has several drawbacks:

(1) Control accuracy is limited. This is because, under different pressures, the amount of oil replenishment or discharge will vary greatly, so under the same standard (the same induction signal), the control accuracy will vary greatly; and, because of the adjustment control process It is necessary to wait for the piston rod to be in place, thereby generating a time difference, and it is precisely because of the existence of the time difference that the amount of hydraulic oil supplied and discharged is deviated from the theoretically calculated amount, thereby affecting the accuracy of the control to a large extent. Sex.

(2) The scope of control is limited. This is because the above control method is based on the fact that each of B1-B4 is disposed at the commutation position. In other words, the above control method considers that when the piston rod reaches the position of B1-B4, it is necessary to perform reverse movement without Consider the case where the above-described commutation position is exceeded, for example, the case where the piston rod exceeds the position of B1 (B1 does not detect the rod end signal). Therefore, the above technical solution cannot detect the problem that the stroke is too long, and only the control that the stroke is not too short can be realized.

(3) Affecting the operating efficiency of the whole machine. This is because, in the above technical solution, the hydraulic cylinder needs to be stopped to wait for the control of the piston rod to be in place, and the number of pumping per minute will be greatly affected, thus reducing the overall efficiency. Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to provide an accurate tandem hydraulic cylinder stroke control method for use in equipment such as concrete pumps. It is also an object of the present invention to provide a stroke control device for a series hydraulic cylinder, and to provide a series hydraulic cylinder. According to an aspect of the invention, a stroke control method for a series hydraulic cylinder is provided, the stroke control method comprising the following steps:

Forming a control region of the hydraulic cylinder stroke by arranging two stroke position collectors in a longitudinal direction of the series hydraulic cylinder;

Determining an oil volume state of the communication chamber according to a positional relationship between a cylinder stroke and the control region and a communication state of the communication chamber of the series hydraulic cylinder, wherein between the cylinder stroke and the control region The positional relationship is: the control area is not reached, the control area is reached, and the control area is exceeded. The oil volume state of the communication chamber is: too small, suitable, excessive;

The oil volume of the communication chamber is adjusted according to the oil volume state of the communication chamber to control the hydraulic cylinder stroke within the control region.

Preferably, the communication cavity is a connected rod cavity or a rodless cavity.

Preferably, the control accuracy of the hydraulic cylinder stroke is set by adjusting the offset distance of the two stroke position collectors in the longitudinal direction of the series hydraulic cylinder.

Preferably, each time the series hydraulic cylinder completes two pumping cycles, the relationship between the cylinder stroke and the control region is determined by counting the presence or absence of a signal from the stroke position collector.

Preferably, when the hydraulic cylinder stroke does not reach the control region or exceeds the control region, the amount of oil replenishment or the amount of oil discharged to the communication chamber is sequentially increased or decreased in each subsequent pumping cycle. Until the cylinder stroke is within the control zone.

Preferably, when the hydraulic cylinder stroke is located in the control region, in each of the following pumping cycles, the amount of oil replenishment or the amount of oil discharged to the communication chamber is kept unchanged until the hydraulic cylinder The trip does not reach the control area or exceeds the control area.

Preferably, the relationship between the cylinder stroke and the control region is controlled by a real-time continuous adjustment of the amount of fuel or the amount of oil discharged from the communication chamber.

According to another aspect of the present invention, there is also provided a stroke control device for a series hydraulic cylinder, the stroke control device comprising:

a signal acquisition device comprising two stroke position collectors staggered in a longitudinal direction of the series hydraulic cylinder to form a control region of the hydraulic cylinder stroke;

a charge and drain hydraulic system, the supplemental drain hydraulic system being in communication with the communication chamber of the series hydraulic cylinder to communicate the hydraulic fluid by replenishing the communication chamber or allowing hydraulic oil to drain in the communication chamber Cavity oil volume Make adjustments; and

a signal processing device connected to the signal acquisition device and connected to the supplemental hydraulic system, according to a positional relationship between the hydraulic cylinder stroke and the control region, and a communication chamber of the series hydraulic cylinder The connected state determines the oil volume state of the communication chamber, and controls the hydraulic fluid system to adjust the oil volume of the communication chamber according to the oil volume state of the communication chamber.

Preferably, the two stroke position collectors are respectively disposed on two hydraulic cylinders of the series hydraulic cylinder; or the two stroke position collectors are disposed on the same hydraulic cylinder of the series hydraulic cylinder.

Preferably, the stroke position collector is disposed on a rod cavity or a rodless cavity of the series hydraulic cylinder; or the series hydraulic cylinder has a water tank, and the stroke position collector is disposed on the water tank.

Preferably, the charge and drain hydraulic system comprises: an oil supply system, a first electromagnetic reversing valve and a second electromagnetic reversing valve, wherein the oil supply system passes the first electromagnetic reversing valve and the second electromagnetic reversing valve a valve communicating with the communication chamber of the series hydraulic cylinder, wherein the first electromagnetic reversing valve is for selecting a communication state of the communication chamber of the series hydraulic cylinder; the second electromagnetic reversing valve is for the communication chamber There are three connection states: a replenishing state in communication with the fuel supply system, a draining state in communication with the low pressure oil passage or the fuel tank, and a disconnection from the fuel supply system and the low pressure oil passage or the fuel tank Cutoff status.

Preferably, the amount of oil replenishment or the amount of oil discharged from the hydraulic system is continuously controlled by controlling an opening time and an opening degree of the second electromagnetic reversing valve.

According to still another aspect of the present invention, a tandem hydraulic cylinder is provided, the tandem hydraulic cylinder comprising: a first hydraulic cylinder having a piston rod reciprocally movable and for providing the piston rod reversing signal At least one commutation signal generator;

a second hydraulic cylinder having a piston rod reciprocally movable and at least one commutation signal generator for providing the piston rod commutation signal,

Wherein, the rod chamber of the first hydraulic cylinder and the rod chamber of the second hydraulic cylinder are connected to be a communication chamber, or the rodless chamber of the first hydraulic cylinder and the rodless chamber of the second hydraulic cylinder Connected to the Unicom cavity,

Wherein, the series hydraulic cylinder further comprises two stroke position collectors which are staggered in the longitudinal direction of the series hydraulic cylinder to form a control region of the hydraulic cylinder stroke.

Preferably, the two stroke position collectors are respectively disposed on the first hydraulic cylinder and the second hydraulic cylinder of the series hydraulic cylinder; or the two stroke position collectors are disposed at the first of the series hydraulic cylinders Hydraulic cylinder or Two hydraulic cylinders.

Preferably, the series hydraulic cylinder has a water tank, and the stroke position collector is disposed on the water tank.

A proportional valve or a servo valve may be added to the hydraulic system of the above-mentioned supplemental drain to control the charge flow or the discharge flow.

According to the technical solution of the present invention, the piston of the hydraulic cylinder can be controlled more accurately by controlling the stroke of the hydraulic cylinder in a control region and adjusting the oil volume of the communication chamber in real time and continuously according to the communication state of the communication chamber. The position of the rod is such that its stroke control accuracy is improved and the stroke can be detected too long and too short.

In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. The invention will now be described in further detail with reference to the drawings. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in FIG In the picture:

1 shows a prior art schematic view of a series hydraulic cylinder having a pressure relief type damping mechanism for adjusting the stroke of the hydraulic cylinder;

2 is a schematic view showing a prior art concrete pump for adjusting the stroke of a hydraulic cylinder by collecting a piston rod end signal;

Figure 3 is a block diagram showing the principle of a series hydraulic cylinder stroke control device according to the present invention;

Figure 4 is a view showing a layout of a signal acquisition device of a stroke control device of a series hydraulic cylinder according to the present invention;

Figure 5 is a view showing another layout of a signal acquisition device of a stroke control device of a series hydraulic cylinder according to the present invention;

Figure 6 is a block diagram showing an embodiment of an embodiment of a charge and drain hydraulic system of a stroke control device for a series hydraulic cylinder in accordance with the present invention. detailed description

The embodiments of the present invention are described in detail below with reference to the drawings, but the invention may be practiced in various different ways as defined and covered by the appended claims. Figure 3 shows a schematic block diagram of a stroke control device for a series hydraulic cylinder in accordance with the present invention. As shown, the stroke control device includes a signal acquisition device 10 for hydraulic cylinder stroke, a makeup and drainage hydraulic system 20, and a signal processing device 30.

The signal acquisition device 10 includes a relatively staggered arrangement in the longitudinal direction of the series hydraulic cylinder, such as two stroke position collectors 18, 19 (such as proximity switches, ie, front proximity switches and rear proximity switches) to form hydraulic cylinder stroke control. region. The term "front" as used herein refers to the horizontal leftward direction of FIGS. 4 and 5, that is, the pumping direction indicated by the arrow; and the so-called "rear" refers to the opposite direction to the above "front", that is, FIG. 4 and The horizontal right direction of Figure 5.

The signal processing device 30 is connected to the charge and drain hydraulic system, and is also electrically connected to the signal acquisition device 10, according to the positional relationship between the hydraulic cylinder stroke and the control region and the communication state of the communication chamber of the series hydraulic cylinder. Determining an oil volume state of the communication chamber, and controlling the hydraulic fluid system to adjust an oil volume of the communication chamber according to an oil volume state of the communication chamber.

a charge and drain hydraulic system 20 in communication with the communication chamber of the series hydraulic cylinder to volume the oil volume of the communication chamber by replenishing the communication chamber with hydraulic oil or allowing hydraulic oil in the communication chamber to bleed Make adjustments.

Wherein, the two stroke position collectors 18, 19 may be respectively disposed on two hydraulic cylinders of the series hydraulic cylinder; or, the two stroke position collectors 18, 19 may be disposed in the series hydraulic cylinder On the same hydraulic cylinder. In addition, the signal acquisition device can be mounted on a rod cavity or a rodless chamber or water tank of the tandem hydraulic cylinder (as shown in Figures 4 and 5), or where other piston or piston rod positions can be detected.

4 and 5 show two partial schematic views of a signal acquisition device of a stroke control device for a series hydraulic cylinder in accordance with the present invention. As shown in Figures 4 and 5, the blowers 11, 13 are used to transport concrete, the water tank 15 is used to cool and provide replacement parts, and the (first) hydraulic cylinder 12 and the (second) hydraulic cylinder 14 are pumping systems. Actuator, commutation signal generators 16, 17 are used to control the pumping system commutation and maintain continuous operation.

The stroke position collectors 18, 19 can be located at the position of the water tank 15 between the hydraulic cylinder and the cylinder for evaluating and judging the stroke state of the pump. The stroke position collectors 18, 19 are arranged one after the other in the longitudinal direction of the series hydraulic cylinder (i.e., in the direction in which the piston rod moves linearly) (or referred to as a staggered arrangement), and are collected by adjusting the two stroke positions. The offset distance of the cylinder in the longitudinal direction of the series hydraulic cylinder sets the control accuracy of the cylinder stroke. That is, the size of the control region L will determine the control accuracy of the cylinder stroke. The smaller the control area L is, the more precise the control is, and the control area L is convenient for adjustment.

In FIG. 4, the stroke position collector 18 is used to detect the stroke of the hydraulic cylinder 12, which is positioned forward; The collector 19 is used to detect the stroke of the hydraulic cylinder 14, and its position is backward. When the stroke position collectors 18, 19 are constituted by the proximity switches, the stroke position collector 18 can be referred to as a front proximity switch, and the stroke position collector 19 is It can be called a rear proximity switch.

In Fig. 5, the stroke position collectors 18, 19 are used to detect the stroke of the same hydraulic cylinder, which is set one after the other. The movement process and stroke of the hydraulic cylinder 12 and the hydraulic cylinder 14 are exactly the same, and the stroke position collectors 18, 19 are respectively used for detecting the strokes of the two hydraulic cylinders (as shown in FIG. 4), and the commutation signal generators 16, 17 are malfunctioning. It can be used as a commutation signal generator, which increases the operational reliability of the concrete pump.

In addition, the assembly of the two proximity switch positions is varied according to different requirements, so there is no limitation, but an example is given, that is, accuracy. Technicians in the industry can make adjustments according to their needs.

Figure 6 is a block diagram showing an embodiment of an embodiment of a charge and drain hydraulic system of a stroke control device for a series hydraulic cylinder in accordance with the present invention.

As shown in FIG. 6, the hydraulic system includes: an oil supply system 23, a first electromagnetic reversing valve, and a second electromagnetic reversing valve, wherein the oil supply system passes through the first electromagnetic reversing valve and The electromagnetic reversing valve is connected to the communication chamber of the series hydraulic cylinder, wherein the first electromagnetic reversing valve is configured to select a communication state of the communication chamber of the series hydraulic cylinder; the second electromagnetic reversing valve enables The communication chamber has three states: a replenishing state in communication with the oil supply system, a draining state in communication with the low pressure oil passage or the fuel tank, and a disconnection from the oil supply system and the low pressure oil passage or the fuel tank The cutoff status.

For example, the charge and drain hydraulic system 20 includes a two-position electromagnetic reversing valve 21 (as an example of a first electromagnetic reversing valve) and a three-position electromagnetic reversing valve 22 (as an example of a second electromagnetic reversing valve) and Oil system 23. Of course, the first electromagnetic reversing valve and the second electromagnetic reversing valve are not limited to the above-mentioned reversing valves 21 and 22, but other suitable reversing valves capable of realizing the reversing action, such as various hydraulic or manual, may be selected. Controlled reversing valve.

Wherein, the connecting chamber of the series hydraulic cylinder connected by the rodless chamber is connected to the oil outlet B of the two-position electromagnetic reversing valve 21, and the connecting chamber of the series hydraulic cylinder connected by the rod chamber is connected to the two-way electromagnetic reversing The oil outlet A of the valve 21, the oil inlet of the two-way reversing valve 21 is connected to the oil outlet A of the three-way reversing valve, and the oil return port is blocked. According to the communication chamber, there is no rod cavity or rod cavity, electromagnet Tla has two states of power loss and power. Wherein, the rodless cavity corresponds to a low pressure state, and the rod cavity corresponds to a high pressure state.

The two-way reversing valve 21 is used to select the communication state of the communication chamber of the series hydraulic cylinder, δΡ, so that the oil supply system 23 selects a connected rod cavity or a rodless chamber that communicates with the series hydraulic cylinder.

In addition, although there are two pairs of series hydraulic cylinders shown in FIG. 6, it is possible to selectively connect to the series as needed. Different communication chambers for hydraulic cylinders. However, it should also be apparent to those skilled in the art that the technical solution of the present invention is equally applicable to the case of a pair of series hydraulic cylinders.

The oil outlet B of the three-way reversing valve 22 is blocked, and the oil inlet port P is connected to the oil supply system 23, and the oil return port T is connected to the oil tank to return oil. The electromagnets T2a and T2b control the three states of the three-position solenoid-operated directional control valve 22: the refilling state, the draining state, and the state of neither replenishing nor draining oil (corresponding to the cut-off state of the Unicom chamber). Therefore, the three-position directional control valve 22 can be actuated according to the selection of the two-position directional control valve 21 (i.e., communicating with the connected rod chamber or the rodless chamber), which will be described later.

The stroke control method of the series hydraulic cylinder is as follows: a control region of the hydraulic cylinder stroke is formed by two stroke position collectors that are relatively staggered in the longitudinal direction of the series hydraulic cylinder, and the communication is controlled by judging the relationship between the hydraulic cylinder stroke and the region. The filling and draining state of the cavity is used to control the stroke of the hydraulic cylinder.

Specifically, the relationship between the oil volume of the communication chamber can be determined by the logic relationship of the stroke position collectors 18, 19, and the control of the two solenoid valves 21, 22 can be used to control the oil volume of the communication chamber, thereby controlling the hydraulic cylinder. The stroke is the pumping stroke.

The control method of the present invention consists of two parts: state judgment, control quantity calculation.

First, the state judgment

The state of the hydraulic cylinder stroke mainly includes three types: not in place, that is, the hydraulic cylinder stroke does not reach the control area; in place, that is, the hydraulic cylinder stroke is located in the control area; and the over-position, that is, the hydraulic cylinder stroke exceeds the control area.

The above three cases can be distinguished by the arrangement of the front and rear proximity switches on the water tank.

Judgment mode: For example, after the completion of two pumping cycles, the signal of the proximity switch is counted: the two proximity switches have no signal... - not in place; the front proximity switch has a proximity switch and no signal... in place; both proximity switches There is a signal... in place. During the operation of the series hydraulic cylinders (such as during pumping), the individual cylinder strokes can be detected in real time. Therefore, each time the series hydraulic cylinder completes two pumping cycles, the relationship between the cylinder stroke and the control region can be determined by counting the presence or absence of signals from the two stroke position collectors.

As shown in Fig. 5, if the piston of the hydraulic cylinder is retracted and the front and rear proximity switches 18, 19 do not sense the signal, the cylinder stroke is short (not in place), but if the front and rear proximity switches 18, 19 sense the signal. Then, the stroke of the hydraulic cylinder is long (over-position). In the present invention, it is desirable that the hydraulic cylinder is retracted between the two proximity switches, which is called "in place".

Judging the state of the fuel volume of the Unicom chamber: When the pressure is low, the cylinder is connected to the cavity without a rod; when the pressure is high, the cylinder is connected. The through cavity is a rod cavity. That is, the communication chamber may be a connected rod cavity or a rodless cavity.

The relationship between the oil volume of the Unicom chamber and the state of the stroke in place is shown in Table 1.

Table I:

Specifically, for example, as shown in FIG. 5, in the case where the communication chamber is a rodless cavity of two hydraulic cylinders of the series hydraulic cylinder, if the stroke of the piston rod 125 is not in place (ie, the stroke position collectors 18, 19) If there is no signal), it means that the volume of oil in the communication chamber is too much; if the stroke of the piston rod 125 is in place (ie, the stroke position collector 18 has a signal, and the stroke position collector 19 has no signal), it means that the lumen is connected. The oil volume is suitable; if the stroke of the piston rod 125 is over-position (ie, the stroke position collector 18 has a signal and the stroke position collector 19 also has a signal), the volume of oil in the communication chamber is too small.

In the case that the communication chamber is a rod cavity of two hydraulic cylinders of the series hydraulic cylinder, if the stroke of the piston rod 125 is not in place (ie, the stroke position collectors 18, 19 have no signal), it means that the inside of the communication chamber is If the stroke of the piston rod 125 is in place (ie, the stroke position collector 18 has a signal and the stroke position collector 19 has no signal), the volume of the oil in the communication chamber is suitable; if the piston rod 125 is If the stroke is over (ie, the stroke position collector 18 has a signal and the stroke position collector 19 also has a signal), the volume of oil in the communication chamber is too large. Second, the control amount calculation

By controlling the opening time of the solenoid valve of the switch to simulate the change of the opening degree of the proportional valve, fine control of the oil in the communication chamber is realized. The entire control process consists of two parts:

(1) Initial state determination:

A) Excessive fluid in the Unicom cavity: Drain, open the solenoid valve 22, the duration is t seconds, that is, the electromagnet T2a is energized for t seconds;

B) Liantong cavity oil is too small: replenishing oil, open solenoid valve 22, lasting for t seconds, that is, T2b electromagnet is energized t seconds.

The determination of the above initial state value is only completed at the first pumping cycle, and the approximation algorithm initial value is determined, which will be described below.

(2) Process value approach: When the cylinder stroke does not reach the control zone or exceeds the control zone, the amount of charge or drain is increased sequentially in each subsequent pumping cycle until the cylinder stroke is within the control zone. Except for all the pumping cycles of the first time, when there is not much more than the joint cavity oil, the oil replenishment amount or the oil discharge amount in the last pumping cycle is kept unchanged until the cylinder stroke does not reach the control area. Or exceed the control area.

The amount of oil replenishment or the amount of oil discharged from the hydraulic system of the above-described replenishing oil can be realized in various ways, for example, by controlling the opening time and opening degree of the second electromagnetic reversing valve 22 for continuous control.

The specific process of the specific algorithm for replenishing or draining oil:

Table 2 shows the manner in which the replenishment amount or discharge rate of the same coefficient is increased in each pumping cycle, that is, the state of the nth pumping cycle is derived based on the state of the n-1th pumping cycle.

When the value of t is less than 100ms, the state is reversed. That is, the oil-filling state becomes drained, the draining state becomes oil-filled, the initial value t is reset, and then the approach is re-approach according to the above algorithm. Those skilled in the art can understand that the above values are t=100ms, the value Kl=1.2, K2=ll, etc., are examples, and can be set as needed.

As can be seen from the above description, in the present invention, by controlling the stroke of the hydraulic cylinder in a control region and adjusting the oil volume of the communication chamber in real time and continuously according to the communication state of the communication chamber, the accuracy can be more accurately The position of the piston rod of the hydraulic cylinder is controlled so that the stroke control accuracy is improved, and the stroke can be detected too long and too short.

Moreover, in the process of adjusting the oil volume, the method of increasing or decreasing the amount of oil in each pumping cycle is adopted to reduce the influence on the pumping frequency of the series hydraulic cylinder, and the hydraulic pressure must be stopped in the comparison document WO1990004104A1. In the case of oil supply and discharge, the stroke of the series hydraulic cylinder can be continuously adjusted and controlled continuously in real time, thereby improving the overall efficiency.

In addition, as shown in FIG. 4 and FIG. 5, the present invention also provides a series hydraulic cylinder, the series hydraulic cylinder comprising: a first hydraulic cylinder 12 having a piston rod 125 capable of reciprocating movement and At least one commutation signal generator 16 for providing a commutation signal of the piston rod 125;

a second hydraulic cylinder 14, the second hydraulic cylinder 14 has a piston rod 145 capable of reciprocating movement and at least one commutation signal generator 17 for providing a commutation signal of the piston rod 145

Wherein, the rod chamber 121 of the first hydraulic cylinder 12 and the rod chamber 141 of the second hydraulic cylinder 14 communicate as a communication chamber, or the rodless chamber 123 of the first hydraulic cylinder 12 and the second The rodless cavity 143 of the hydraulic cylinder 14 is connected to the communication chamber.

Wherein, the series hydraulic cylinder further comprises two stroke position collectors 18, 19 which are staggered in the longitudinal direction of the series hydraulic cylinder to form a control region of the hydraulic cylinder stroke .

The series hydraulic cylinder is suitable for the stroke control method and the stroke control device of the series hydraulic cylinder which has been described in detail above, and will not be described in detail herein.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A stroke control method for a series hydraulic cylinder, characterized in that the stroke control method comprises the following steps: forming a hydraulic cylinder stroke control by arranging two stroke position collectors in a longitudinal direction of the series hydraulic cylinder Area

2. The stroke control method according to claim 1, wherein the communication chamber is a connected rod cavity or a rodless chamber.

The stroke control method according to claim 1 or 2, wherein the hydraulic cylinder is set by adjusting a shift distance of the two stroke position collectors in a longitudinal direction of the series hydraulic cylinder The control accuracy of the stroke.

The stroke control method according to claim 1 or 2, wherein each time the series hydraulic cylinder completes two pumping cycles, the presence or absence of a signal of the stroke position collector is determined to determine The relationship between the stroke of the hydraulic cylinder and the control region.

5. The stroke control method according to claim 4, wherein when the cylinder stroke does not reach the control region or exceeds the control region, it is sequentially increased in each subsequent pumping cycle or The amount of oil replenishment or the amount of oil discharged to the communication chamber is reduced until the cylinder stroke is within the control region.

6. The stroke control method according to claim 4, wherein when the cylinder stroke is located in the control region, in the next pumping cycle, the compensation for the communication chamber is maintained. The amount of oil or the amount of oil remaining does not change until the cylinder stroke does not reach the control zone or exceeds the control zone.

7. The stroke control method according to claim 1, wherein the relationship between the cylinder stroke and the control region is continuously adjusted in real time by the amount of oil replenishment or the amount of oil discharged from the communication chamber. control.

8. A stroke control device for a series hydraulic cylinder, wherein the stroke control device comprises: a signal acquisition device, the signal acquisition device comprising two stroke position collectors staggered in a longitudinal direction of the series hydraulic cylinder, To form a control area for the stroke of the hydraulic cylinder;

a charge and drain hydraulic system, the supplemental drain hydraulic system being in communication with the communication chamber of the series hydraulic cylinder to communicate the hydraulic fluid by replenishing the communication chamber or allowing hydraulic oil to drain in the communication chamber The volume of the oil in the chamber is adjusted; and

9. The stroke control device according to claim 8, wherein the two stroke position collectors are respectively disposed on two hydraulic cylinders of the series hydraulic cylinder; or the two stroke position collectors are set On the same hydraulic cylinder of the series hydraulic cylinder.

10 . The stroke control device according to claim 8 , wherein the stroke position collector is disposed on a rod cavity or a rodless cavity of the series hydraulic cylinder; or the series hydraulic cylinder has a water tank. The stroke position collector is disposed on the water tank.

11. The stroke control device according to claim 8, wherein the charge and drain hydraulic system comprises: an oil supply system, a first electromagnetic reversing valve, and a second electromagnetic reversing valve, wherein the oil supply system passes The first electromagnetic reversing valve and the second electromagnetic reversing valve are in communication with the communication chamber of the series hydraulic cylinder, wherein the first electromagnetic reversing valve is configured to select a communication state of the communication chamber of the series hydraulic cylinder The second electromagnetic reversing valve has three connected states: a replenishing state in communication with the oil supply system, a draining state in communication with the low pressure oil passage or the oil tank, and the supply The off state of the oil system and the low pressure oil circuit or the fuel tank are not connected.

12. The stroke control device according to claim 11, wherein the replenishing amount or the amount of oil discharged from the hydraulic system is continuously controlled by controlling an opening time and an opening degree of the second electromagnetic reversing valve. control.

13. The stroke control device according to claim 8, wherein the communication chamber is a connected rod cavity or a rodless chamber.

14. A series hydraulic cylinder, the series hydraulic cylinder comprising:

a first hydraulic cylinder (12) having a piston rod (125) capable of reciprocating movement and at least one commutation signal generator for providing a commutation signal of the piston rod (125) (16) );

a second hydraulic cylinder (14) having a piston rod (145) reciprocally movable and at least one commutation signal generator for providing a commutation signal of the piston rod (145) (17) ),

Wherein, the rod chamber (121) of the first hydraulic cylinder (12) and the rod chamber (141) of the second hydraulic cylinder (14) communicate as a communication chamber, or the first hydraulic cylinder (12) The rodless chamber (123) is in communication with the rodless chamber (143) of the second hydraulic cylinder (14) as a communication chamber.

The utility model is characterized in that the series hydraulic cylinder further comprises two stroke position collectors (18, 19), and the two stroke position collectors (18, 19) are staggered in the longitudinal direction of the series hydraulic cylinder to form The control area of the hydraulic cylinder stroke.

The series hydraulic cylinder according to claim 14, wherein the two stroke position collectors (18, 19) are respectively disposed at a first hydraulic cylinder (12) and a second hydraulic pressure of the series hydraulic cylinder On the cylinder (14); or the two stroke position collectors (18, 19) are disposed on the first hydraulic cylinder (12) or the second hydraulic cylinder (14) of the series hydraulic cylinder.

16. The stroke control device according to claim 14, wherein the series hydraulic cylinder has a water tank, and the stroke position collector is disposed on the water tank.