CN206592380U - Crank block type feedback digital hydraulic cylinder - Google Patents

Abstract

The utility model discloses a crank slider type feedback digital hydraulic cylinder, which includes a slide valve, a hydraulic cylinder and a stepping motor. The hydraulic cylinder includes a hydraulic cylinder cavity and a piston. The hydraulic cylinder cavity is divided into an upper cavity and a lower cavity. The spool valve includes a valve cavity and a valve core, one end of the valve core is connected to the stepping motor, the other end of the valve core is fixed to one end of the screw rod, and the other end of the screw rod is provided with a feedback nut, and the feedback nut and the screw rod form a screw nut pair , the feedback digital hydraulic cylinder also includes a crank-slider mechanism. The crank-slider mechanism includes a piston rod, a connecting rod, a crank, a connecting piece and a rotating shaft. The lower end of the piston rod is fixed to the piston, and the upper end of the piston rod extends from the upper cavity of the hydraulic cylinder to the upper Above the cavity, the upper end of the piston rod is hinged with one end of the connecting rod through the connecting piece, the other end of the connecting rod is hinged with the crank, and the crank is connected with the feedback nut through the rotating shaft. The digital hydraulic cylinder can not only accurately control the operating speed and displacement of the hydraulic cylinder, but also has the characteristics of simple structure, rapid and continuous feedback response.

Description

Slider Crank Feedback Digital Hydraulic Cylinder

technical field

The invention relates to the field of digital hydraulic cylinders, in particular to a crank slider type feedback digital hydraulic cylinder.

Background technique

The hydraulic cylinder is the core part of the hydraulic system, a hydraulic actuator, and an energy conversion device. As the needs of society and industry put forward higher requirements for the control accuracy of hydraulic components, it is obvious that traditional hydraulic technology cannot meet the existing industrial production requirements in terms of accuracy and control.

Therefore, in order to overcome the problem of poor accuracy of traditional hydraulic cylinders, digital hydraulic cylinders came into being. Digital hydraulic cylinders integrate stepping motors, hydraulic slide valves, and feedback mechanisms inside the hydraulic cylinders. When in use, the hydraulic oil source is connected , all functions directly control the moving length vector of each component in the hydraulic cylinder through the digital pulse signal sent by the programmable logic controller (PLC). By combining digital control technology with the hydraulic cylinder, the direction control, speed control and position control of the hydraulic cylinder are more precise.

At present, digital hydraulic cylinders mainly include stepper motors or servo motors, hydraulic cylinders, hydraulic slide valves, sensors, and feedback mechanisms. Digital technology controls the angular displacement of stepper motors to control the opening of hydraulic slide valves, and then controls oil flow. The oil volume and flow rate can finally control the operating speed and displacement of the hydraulic cylinder. Among them, the feedback mechanism mainly collects the displacement speed information of the hydraulic cylinder through the sensor and feeds it back to the stepping motor, and then adjusts the angular displacement of the stepping motor to achieve precise control. Hydraulic cylinder, this process is the closed-loop control of the stepper motor. This kind of closed-loop control of the stepper motor has problems such as complexity, hysteresis, nonlinearity and poor anti-interference, and usually the structure of this feedback mechanism is relatively complicated. In order to overcome the shortcomings of the stepper motor closed-loop control, a closed-loop digital control of the displacement of the hydraulic cylinder appears. For example, the Chinese invention patent (authorized announcement date CN103148047B authorized announcement date 2016.03.02) discloses an internal feedback digital servo hydraulic cylinder. The slide valve of this invention The spool of the spool is driven and controlled by the first motor, and the feedback screw sleeve of the slide valve is driven and controlled by the second motor. The hysteresis telescopic displacement sensor feeds back the displacement signal of the hydraulic cylinder to the corresponding driver of the second motor, and the driver controls the operation of the second motor. The control of the relative movement of the feedback screw sleeve and the spool realizes the closed-loop digital control of the displacement of the hydraulic cylinder. This invention includes a first motor to drive the displacement of the slide valve and a second motor to execute the feedback command. Because the second motor needs Only through the sensor, the motor driver can perform the feedback action. Therefore, this feedback mechanism still has the disadvantage of feedback response lag.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a crank slider type feedback digital hydraulic cylinder, which can not only accurately control the operating speed and displacement of the hydraulic cylinder, but also has the characteristics of simple structure, rapid and continuous feedback response .

In order to achieve the above object, the technical scheme adopted in the present invention is:

The crank slider type feedback digital hydraulic cylinder includes a slide valve, a hydraulic cylinder and a stepping motor. The hydraulic cylinder includes a hydraulic cylinder cavity and a piston arranged in the hydraulic cylinder cavity that can move up and down along the inner wall of the hydraulic cylinder. The piston will The cavity of the hydraulic cylinder is divided into an upper cavity and a lower cavity; the slide valve includes a valve cavity and a spool moving left and right in the valve cavity, and the valve cavity is opened with a high-pressure oil inlet, a first oil outlet, a second The oil outlet, the first flow port communicated with the upper cavity of the hydraulic cylinder, and the second flow port communicated with the lower cavity of the hydraulic cylinder; one end of the spool is connected to the stepper motor through a coupling, and the other One end is fixed to one end of the screw rod, and the other end of the screw rod is provided with a feedback nut, and the feedback nut and the screw rod form a screw nut pair, wherein the crank slider type feedback digital hydraulic cylinder also includes a drive feedback A slider crank mechanism in which the nut rotates, the slider crank mechanism includes a piston rod, a connecting rod, a crank, a connecting piece and a rotating shaft, the lower end of the piston rod is fixed to the piston, and the upper end of the piston rod protrudes from the upper cavity of the hydraulic cylinder Above the upper cavity, the upper end of the piston rod is hinged with one end of the connecting rod through a connecting piece, the other end of the connecting rod is hinged with a crank, and the crank is connected with a feedback nut through a rotating shaft.

Preferably, the connecting rod includes a vertical rod and a horizontal rod, the lower end of the vertical rod and one end of the horizontal rod are fixed to form an "L" shaped rod, the upper end of the vertical rod is hinged to the connecting piece, the The other end of cross bar is hinged with crank. Wherein the connecting rod is an "L" shaped rod, so that the plane of the crank's rotation trajectory is perpendicular to the plane where the piston's thrust or pulling force is located, so that the nut rotates more smoothly.

Preferably, the slide valve is a four-shouldered four-sided slide valve. Compared with the two-shoulder four-side slide valve, the three-shoulder four-side slide valve has a better fluid linear relationship.

Preferably, the slider crank type feedback digital hydraulic cylinder further includes a programmable controller, and the programmable controller directly transmits the output pulse signal to the motor driver, and the motor driver drives the stepping motor to operate. Through the programmable controller, the output pulse signal is directly transmitted to the stepper motor driver to drive the stepper motor to rotate, without the conversion of the digital/analog converter, which realizes the real "digital" control and solves the problem of analog signal transmission. The interference problem makes the control system more stable.

Preferably, the output pulse signal of the programmable controller is set according to the displacement, speed and direction of the hydraulic cylinder.

The advantages of the present invention are:

1. In the present invention, the crank slider mechanism is used to drive the feedback nut to rotate to complete the feedback process of the digital hydraulic cylinder. Compared with the traditional sensor feedback, the crank slider mechanism responds more quickly and is not affected by signal interference. Compared with the rack and pinion mechanism, the slider crank mechanism has more continuous feedback, so that the operating speed and displacement of the hydraulic cylinder are more accurate.

2. What the traditional digital hydraulic cylinder adopts is the closed-loop control to the stepper motor (as shown in Figure 4). In the present invention, the slide valve is directly closed-loop controlled by the slider crank mechanism (as shown in Figure 5). For the stepper motor, it is The open-loop control overcomes the problems of complexity, hysteresis, nonlinearity and poor anti-interference in the closed-loop control of the stepping motor.

3. The output pulse signal of the programmable controller in the existing digital hydraulic cylinder is set according to the opening of the valve port in the slide valve, and the position and speed signal of the hydraulic cylinder is collected by the sensor and fed back to the stepper motor to adjust the valve. Compared with this control method, it is more direct and simple to set the output pulse signal directly according to the displacement, speed and direction of the hydraulic cylinder, and avoid the defect that the sensor is susceptible to interference.

Description of drawings

Fig. 1 is a schematic structural view of the slider crank type feedback digital hydraulic cylinder of the present invention (the slider crank type feedback digital hydraulic cylinder is in a static state);

Fig. 2 is a schematic diagram of the structure of the crank-slider type feedback digital hydraulic cylinder when the stepper motor is rotating forward;

Fig. 3 is a schematic structural diagram of a crank-slider type feedback digital hydraulic cylinder when the stepping motor is reversed;

Figure 4 is a schematic diagram of a traditional digital hydraulic cylinder for closed-loop control of a stepping motor;

Fig. 5 is a schematic diagram of the closed-loop control of the slide valve by the crank-slider type feedback digital hydraulic cylinder of the present invention;

The labels of the components in the figure are as follows: slide valve 1, hydraulic cylinder 2 (including hydraulic cylinder cavity 21, upper cavity 21a, lower cavity 21b, piston 22), stepping motor 3, valve cavity 4 (including High-pressure oil inlet 4a, first oil outlet 4b, second oil outlet 4c, first flow port 4d, second flow port 4e), valve core 5, coupling 6, screw rod 7, feedback nut 8, crank Slider mechanism 9 (including piston rod 9a, connecting rod 9b, crank 9c, connecting piece 9d, rotating shaft 9e), vertical bar 10, cross bar 11, programmable controller 12, motor driver 13.

detailed description

In order to better understand the present invention, the invention will be described in detail below in conjunction with the accompanying drawings and specific examples.

As shown in Figure 1, the crank slider type feedback digital hydraulic cylinder includes a four-shouldered four-side slide valve 1, a hydraulic cylinder 2 and a stepping motor 3, and the hydraulic cylinder 2 includes a hydraulic cylinder cavity 21 and a hydraulic cylinder cavity 21 A piston 22 that can move up and down along the inner wall of the hydraulic cylinder, the piston 22 divides the hydraulic cylinder cavity 21 into an upper cavity 21a and a lower cavity 21b; the four-shoulder four-side slide valve 1 includes a valve cavity 4 and a valve cavity The spool 5 that moves left and right inside the valve chamber 4 is provided with a high-pressure oil inlet 4a, a first oil outlet 4b, a second oil outlet 4c, and a first flow port that communicates with the upper cavity 21a of the hydraulic cylinder 2 4d and the second flow port 4e communicating with the lower cavity 21b of the hydraulic cylinder 2; one end of the spool 5 is connected to the stepper motor 3 through a coupling 6, the other end of the spool 5 is fixed to one end of the screw rod 7, and the screw rod 7 The other end is provided with a feedback nut 8, and the feedback nut 8 and the screw rod 7 form a screw nut pair, wherein the crank-slider type feedback digital hydraulic cylinder also includes a crank-slider mechanism 9 that can drive the feedback nut 8 to rotate, and the crank-slider mechanism 9 includes a piston rod 9a, a connecting rod 9b, a crank 9c, a connecting piece 9d and a rotating shaft 9e, the lower end of the piston rod 9a is fixed to the piston 22, and the upper end of the piston rod 9a extends from the upper cavity 21a of the hydraulic cylinder 2 to above the upper cavity 21a, The upper end of the piston rod 9a is hinged with one end of the connecting rod 9b through the connecting piece 9d, the other end of the connecting rod 9b is hinged with the crank 9c, and the crank 9c is connected with the feedback nut 8 through the rotating shaft 9e, wherein the connecting rod 9b includes a vertical rod 10 With a cross bar 11, the lower end of the vertical bar 10 is fixed to one end of the cross bar 11 to form an "L" shaped bar, the upper end of the vertical bar 10 is hinged with the connecting piece 9d, and the other end of the horizontal bar 11 is hinged with the crank 9c .

The crank slider type feedback digital hydraulic cylinder also includes a programmable controller 12, and the programmable controller 12 directly transmits the output pulse signal to the motor driver 13, and the motor driver 13 drives the stepper motor 3 to operate, wherein the programmable controller 12 The output pulse signal is set according to the displacement, speed and direction of the operation of the hydraulic cylinder 2 .

Slide valve 1, hydraulic cylinder 2 (including hydraulic cylinder cavity 21, upper cavity 21a, lower cavity 21b, piston 22), stepper motor 3, valve cavity 4 (including high pressure oil inlet 4a, first Oil outlet 4b, second oil outlet 4c, first flow port 4d, second flow port 4e), valve core 5, coupling 6, screw rod 7, feedback nut 8, crank slider mechanism 9 (wherein, It includes a piston rod 9a, a connecting rod 9b, a crank 9c, a connecting piece 9d, a rotating shaft 9e), a vertical bar 10, a cross bar 11, a programmable controller 12, and a motor driver 13.

Working principle of the present invention: in conjunction with Fig. 1 and shown in Fig. 5, programmable controller 12 transmits the pulse signal of output to motor driver 13, and motor driver 13 drives stepper motor 3 to rotate, and produces certain angle of rotation, because stepper motor The coupling 6 is connected to one end of the valve core 5, so the rotation of the stepping motor 3 drives the rotation of the valve core 5, and the rotation of the valve core 5 further drives the rotation of the screw rod 7 fixedly connected with the valve core. The screw rod 7 is equipped with a feedback nut 8. Since the feedback nut 8 is connected to the slider crank mechanism 9, and the driving force of the hydraulic cylinder 2 is much larger than the driving force required to rotate the spool 5, when the stepping motor 3 rotates to drive the spool 5 to rotate , the feedback nut 8 does not rotate, so the screw rod 7 is forced to drive the spool 5 to move axially, and then the first flow port 4d and the second flow port 4e are opened. The displacement direction of the spool 5 determines the first flow port 4d and the second flow port. Whether the second flow port 4e is the oil inlet direction or the oil output direction, as shown in Figure 1, the motor stops rotating, the valve core 5 blocks the first flow port 4d and the second flow port 4e, the high pressure oil Ps does not flow, and the whole device is at rest state, as shown in Figure 2, the motor rotates forward, drives the spool 5 to move to the right, high-pressure oil flows in from the high-pressure oil inlet 4a, flows into the lower chamber 21b of the hydraulic cylinder 2 through the second flow port 4e, and pushes the piston 22 to move upward , the low-pressure oil Po in the upper cavity 21a flows out through the first circulation port 4d and the first oil outlet 4b in turn, and when the piston 22 moves upward, the crank slider mechanism 9 is started, and the crank slider mechanism 9 drives the feedback nut 8 Rotate, the direction of rotation of the feedback nut 8 is opposite to the direction of rotation of the stepper motor 3, the feedback nut 8 and the screw rod 7 form a screw nut pair, the rotation of the feedback nut 8 drives the screw rod 7 to generate displacement to the left, thereby giving the spool 5 a Feedback force to the left, this feedback makes the hydraulic cylinder 2 run more smoothly, and through the slider crank mechanism 9 compared with other transmission mechanisms such as rack and pinion transmission mechanisms, this feedback is more continuous so that the hydraulic cylinder The running displacement and speed are more accurate. Compared with the sensor feedback, the crank slider mechanism responds more quickly and is not affected by signal interference. The reverse rotation of the motor is shown in Figure 3, and its principle is the same as that of the above-mentioned motor forward rotation, so it will not be repeated here.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (5)

1. a kind of crank block type feedback digital hydraulic cylinder, including guiding valve (1), hydraulic cylinder (2) and stepper motor (3), the liquid Cylinder pressure (2) includes hydraulic cylinder cavity (21) and the piston that can be moved up and down in hydraulic cylinder cavity (21) along the hydraulic pressure inside wall of cylinder (22), hydraulic cylinder cavity (21) is divided into upper cavity (21a) and lower chamber (21b) by the piston (22)；The guiding valve (1) includes High pressure oil inlet (4a) is provided with valve pocket (4) and the valve element (5) of valve pocket (4) interior side-to-side movement, the valve pocket (4), first is gone out Hydraulic fluid port (4b), the second oil-out (4c), the first communication port (4d) connected with hydraulic cylinder (2) upper cavity (21a) and and hydraulic pressure The second communication port (4e) of cylinder (2) lower chamber (21b) connection；Described valve element (5) one end passes through shaft coupling (6) and stepper motor (3) connect, one end of valve element (5) other end and screw mandrel (7) is fixed, screw mandrel (7) other end is provided with feedback nut (8), the feedback nut (8) constitutes feed screw nut pair with screw mandrel (7), it is characterised in that：The crank block type feedback digital Hydraulic cylinder also includes that the slider-crank mechanism (9) of feedback nut (8) rotation can be driven, and the slider-crank mechanism (9) includes living Stopper rod (9a), connecting rod (9b), crank (9c), connector (9d) and rotating shaft (9e), piston rod (9a) lower end and piston (22) fixed, piston rod (9a) upper end is extend out to out of hydraulic cylinder (2) upper cavity (21a) above upper cavity (21a), described Piston rod (9a) upper end is linked by one end of connector (9d) and connecting rod (9b), the other end and crank of the connecting rod (9b) (9c) is linked, and the crank (9c) is connected by rotating shaft (9e) with feedback nut (8).

2. crank block type feedback digital hydraulic cylinder according to claim 1, it is characterised in that：The connecting rod (9b) includes Composition " L " shape bar is fixed in a piece montant (10) and a cross bar (11), the lower end of the montant (10) with one end of cross bar (11), The upper end of the montant (10) is hinged with connector (9d), and the other end and the crank (9c) of the cross bar (11) are hinged.

3. crank block type feedback digital hydraulic cylinder according to claim 1, it is characterised in that：The guiding valve (1) is four Convex shoulder four-side.

4. according to crank block type feedback digital hydraulic cylinder according to any one of claims 1 to 3, it is characterised in that：It is also Including programmable controller (12), the pulse signal of output is transferred directly to motor driver by the programmable controller (12) (13), the motor driver (13) drives stepper motor (3) running.

5. crank block type feedback digital hydraulic cylinder according to claim 4, it is characterised in that：The programmable controller (12) displacement, speed and the direction that the pulse signal of output is run according to hydraulic cylinder (2) are set.