Servo hydraulic transmission mechanism

[0023] figure 1 It is a servo hydraulic cylinder including a servo hydraulic valve of the present invention. The servo hydraulic cylinder includes a servo hydraulic valve (001) and a hydraulic cylinder (002) combined with it. The servo hydraulic valve (001) includes a housing (1), a control valve (003), a sensor (004), and a gear pair (005). The gear pair (005) includes a driving gear (2), a driven gear A (3) and a driven gear B (4). The control valve (003) includes a valve housing (5), a valve core (6), a valve sleeve (7), and a stepping motor (8). One end of the valve sleeve (7) is fixedly connected with the driven gear A (3), and the valve core (6) is inserted into the inner hole of the valve sleeve (7). The valve housing (5) is a part of the housing (1), the stepping motor (8) is installed on the end surface of the valve housing (5), and its output shaft is inserted into the valve core (6). ) The inner hole at one end is connected with a key. The outer wall of the valve housing (5) has a hydraulic medium inlet P, hydraulic medium outlets Ta and Tb, and inlets A and B communicating with the hydraulic cylinder (002). The outer wall of the valve sleeve (7) has 5 annular grooves (9) respectively communicating with the P, Ta, Tb, A, and B ports, and each annular groove (9) of the 5 annular grooves (9) There are at least two radial holes (10) arranged symmetrically on the circumference and axially arranged in a row at the bottom. The cylinder surface on both sides of the valve core (6) adjacent to the radial hole (10) respectively has two axial grooves (11) which can communicate with two adjacent radial holes (10) respectively. The sensor device (004) at least includes a transmission shaft (12), a displacement sensor (13), and may also include a pressure sensor (not shown). One end of the transmission shaft (12) is fixedly connected with the driven gear B (4); the displacement sensor (13) is installed on the housing (1), and its rotation shaft is connected to the transmission The shaft (12) is fixedly connected. The pressure sensor is installed on the valve housing (5) and communicates with the annular groove (9) communicating with one of the A and B ports.

[0024] The hydraulic cylinder (002) includes a cylinder body (14), a piston rod (15), a screw pair (006) that converts linear motion into a rotary motion, a partition (16), and the piston of the piston rod (15) The end has a central deep hole (17), the nut (18) of the screw pair (006) is fixedly connected to the piston end of the piston rod (15), and the threaded end of the screw (19) of the screw pair (006) Engage with the nut (18). The housing (1) of the servo hydraulic valve (001) is fixedly connected to the tail end of the cylinder (14) and a partition (16) acting as an isolation function is fixed, and the drive gear (2) is installed on the partition ( 16) It is on and fixedly connected with the other end of the screw (19). The valve core (6) and the valve sleeve (7) can each rotate relative to the valve housing (5). The valve core (6) rotates in the forward and reverse directions relative to the valve sleeve (7) to switch on or off the hydraulic medium channel, and control the piston rod (15) to run or stop in the forward and reverse directions.

[0025] figure 2 It is a servo hydraulic cylinder including another servo hydraulic valve of the present invention. The servo hydraulic cylinder includes a servo hydraulic valve (007) and a hydraulic cylinder (002) combined with it. It differs from the above-mentioned embodiment in that the output shaft of the stepping motor (8) is slidably inserted into the inner hole of one end of the valve core (20) and connected with a feather key, and the other end of the valve core (20) is externally threaded with the valve The inner thread drive connection at one end of the sleeve (21). The inner wall of the valve housing (22) has two annular grooves (23) respectively connected to the A and B ports, and the valve core (20) has two annular convex ridges (24) corresponding to the annular grooves (23). ). The valve core (20) and the valve sleeve (21) respectively rotate relative to the valve housing (22). When the valve core (20) rotates in the forward and reverse directions relative to the valve sleeve (21), the axial displacement is generated to connect or shut off the hydraulic medium. aisle.

[0026] image 3 , Figure 4 It shows the opening and closing pressing mechanism of a vertical filter press of the present invention. It comprises a lower pressing plate (25), an upper pressing plate (26) which can move back and forth relative to the lower pressing plate (25), and a spiral transmission mechanism (008) arranged in pairs on both sides of the lower pressing plate (25) and the upper pressing plate (26). Each set of said screw drive mechanism (008) includes its own support tube (27), nut (28), lead screw (29), hydraulic motor (30), servo hydraulic valve (009), said support tube ( The lower end of 27) is fixed on the lower pressing plate (25), the nut (28) is fixed on the upper end of the support tube (27), and the threaded section of the lower end of the lead screw (29) is engaged with the nut (28). The lower end of the servo hydraulic valve (009) is fixedly connected to the upper pressure plate (26), and the drive gear (2) (not shown) in the servo hydraulic valve (009) is fixedly connected to the top of the lead screw (29) The hydraulic motor (30) is installed at the top of the servo hydraulic valve (009), and the output shaft of the hydraulic motor (30) is inserted into the inner hole at the top of the screw (29) and fixedly connected with a key. The lead screw (29) is driven by the hydraulic motor (30) to rotate in forward and reverse directions, and drives the upper pressing plate (26) to move up and down. The pair of hydraulic motors (30) are controlled by the servo hydraulic valve (009) to operate synchronously.

[0027] Figure 5 It shows another open-close pressing mechanism of the vertical filter press of the present invention. It includes a lower pressure plate (25), an upper pressure plate (26), and a pair of servo hydraulic cylinders (010) arranged on both sides of the upper and lower pressure plates. The tail end of the servo hydraulic cylinder (010) is fixed on the lower pressure plate (25). The top end of the piston rod (15) of the cylinder (010) is fixedly connected with the upper pressing plate (26) to drive the upper pressing plate (26) to move up and down.

[0028] Image 6 Shows an embodiment of the pressing mechanism of a horizontal filter press, which includes a fixed pressing plate (31), a movable pressing plate (32), a bracket (33), a horizontal beam (34), and 2 sets of servo hydraulic cylinders (35) . The two ends of the horizontal beam (34) are respectively fixedly connected with the fixed pressing plate (31) and the bracket (33). The servo hydraulic cylinder (35) is installed on the bracket (33). The movable pressing plate (32) is placed on the horizontal beam (34) and connected with the top end of the piston rod (36) of the servo hydraulic cylinder (35).

[0029] The working conditions of the servo hydraulic cylinder of the present invention are as follows: (see figure 1 )

[0030] 1. Start: Start the stepper motor (8) to drive the valve core (6) to rotate relative to the valve sleeve (7), so the P port is connected with the A port, the B port is connected with the Tb port, and the hydraulic medium enters the servo hydraulic cylinder The hydraulic medium in the rear cavity (37) and the front cavity (38) is discharged through the Tb port. The piston rod (15) is pushed out by pressure and drives the screw (19) to rotate through the nut (18). The screw (19) drives the valve sleeve (7) to rotate through the gear pair (005). The rotation direction of the valve sleeve (7) is the same as that of the valve core (6). When the rotation speed of the valve sleeve (7) is less than the average rotation speed of the valve core (6), the valve core (6) and the valve sleeve (7) The relative angular displacement of) increases, the opening degree of the control valve (003) increases, the flow of the hydraulic medium increases, and the moving speed of the piston rod (15) increases. The valve sleeve (7) plays a role of speed feedback and automatic tracking adjustment. When the rotation speed of the valve sleeve (7) is greater than the average rotation speed of the valve core (6), the relative angular displacement of the valve core (6) and the valve sleeve (7) decreases, and the moving speed of the piston rod (15) decreases. The movement speed of the piston rod (15) can be conveniently changed by adjusting the speed of the stepping motor (8). When the stepping motor (8) rotates in the opposite direction, the hydraulic medium flows in the opposite direction, the piston rod (15) retracts, and the valve sleeve (7) also rotates in the opposite direction.

[0031] 2. Stop: Turn off the stepping motor (8), the valve sleeve (7) will automatically track the spool (6), and the relative angular displacement with the spool (6) will automatically be reduced to 0. At this time, the passages between the ports A, B and P, Ta, and Tb on the valve housing (5) are blocked by the valve core (6), and the piston rod (15) stops and keeps its position unchanged. The stroke of the piston rod (15) accurately corresponds to the number of revolutions of the stepping motor (8), and the stroke of the piston rod (15) can be conveniently controlled by setting the number of revolutions of the stepping motor (8) through the controller.

[0032] 3. Monitoring: the linear motion of the piston rod (15) when it is telescoping, is transformed into the rotation motion of the screw (15) through the screw pair (006), and passed through the driving gear (2), the driven gear (4) and the transmission shaft (12). ) Drive the input shaft of the displacement sensor (13) to rotate, and feedback the position and speed of the piston rod (15) to the electrical automatic control system in real time with electrical signals. The electrical automatic control system performs calculations based on the feedback signals and the set control parameters. After analysis and comparison, the stepping motor (8) is adjusted in real time, including normal adjustment and failure prevention, alarm, and shutdown. For example, the relative angular displacement of the valve sleeve (7) and the spool (6) exceeds the set limit. Downtime.