CN207297964U - The machine feedback formula Numeric hydraulic cylinder that a kind of valve pocket can be servo-actuated - Google Patents

Abstract

The utility model discloses a mechanical feedback type digital hydraulic cylinder with a followable valve sleeve, the main shaft of the servo motor is connected with a screw rod, the other end of the screw rod cooperates with the inner thread of a valve core, the valve core is embedded in the valve sleeve, and the screw rod drives the valve core Slide along the axial direction of the valve sleeve, the valve sleeve is embedded in the valve body, the outer wall of the valve core is provided with a plurality of bosses, the inner wall of the valve sleeve is provided with grooves corresponding to the valve core bosses, the valve core and the valve sleeve cooperate to form a Three-position four-way hydraulic valve, the side wall of the valve body is radially provided with an oil passage hole corresponding to the three-position four-way hydraulic valve, and the valve sleeve is provided with an internal thread near the end of the cylinder body to cooperate with the external thread of the ball screw. Driven by the ball screw, the sleeve can slide axially along the valve body, the other end of the ball screw is embedded in the hollow piston rod, and the screw nut is arranged on the piston of the piston rod. The utility model adds a valve sleeve structure on the outside of the valve core, and realizes the dynamic feedback of the position of the hydraulic cylinder through the follow-up of the valve sleeve, thus disconnecting the mechanical connection between the valve core and the ball screw, and improving the controllability of the valve core.

Description

A mechanical feedback digital hydraulic cylinder with a valve sleeve that can be moved

technical field

The utility model relates to the technical field of digital hydraulics, in particular to a mechanical feedback digital hydraulic cylinder with a followable valve sleeve.

Background technique

Traditional digital hydraulic cylinders are basically divided into direct drive by stepping/servo motors and control of the spool movement of the hydraulic valve. With a mechanical feedback structure directly connected to the ball screw and the spool, direct digital signal control can be achieved, and can reach 0.01 mm position control accuracy. However, since one end of the spool is connected to the output shaft of the stepper/servo motor and the other end is connected to the ball screw of the hydraulic cylinder, both ends will receive the driving force of the stepper/servo motor and the feedback force of the ball screw at the same time. It is not easy to realize the dynamic matching of the driving force and the feedback force in the whole working cycle, which affects the dynamic response of the spool and the hydraulic cylinder, and there are also hidden dangers of failure.

Contents of the invention

In view of the above existing problems, the utility model proposes a mechanical feedback digital hydraulic cylinder structure with a followable valve sleeve, which can solve the two-way solid connection problem of the digital hydraulic cylinder spool, and fundamentally improve the force of the spool. Therefore, the movement performance of the spool is improved.

The technical solution adopted by the utility model to solve the technical problem is: a mechanical feedback digital hydraulic cylinder with a valve sleeve that can follow the movement, including a servo motor, a screw, a valve core, a valve sleeve, a valve body, a ball screw, and a lead screw. Nut, piston rod, cylinder body, the main shaft of the servo motor is connected with one end of the screw rod through a coupling, the other end of the screw rod matches the internal thread of the valve core, the valve core is embedded in the valve sleeve, and the screw rod can drive the valve core along the valve sleeve Axial sliding, the valve sleeve is embedded in the valve body, the outer wall of the valve core is provided with a plurality of bosses, the inner wall of the valve sleeve is provided with grooves corresponding to the bosses of the valve core, the valve core and the valve sleeve cooperate to form a Three-position four-way hydraulic valve, the side wall of the valve body is radially provided with an oil passage hole corresponding to the three-position four-way hydraulic valve, and the valve sleeve is provided with an internal thread at the end close to the cylinder body to match the external thread at one end of the ball screw. Cooperate, the valve sleeve can slide along the axial direction of the valve body driven by the ball screw, the other end of the ball screw is embedded in the hollow piston rod, the screw nut is set on the piston of the piston rod, and the ball screw can only rotate , under the action of internal friction and external load, the piston rod can only do translational motion, but cannot rotate.

The utility model adds a valve sleeve structure on the outside of the valve core of the digital hydraulic cylinder, and realizes the dynamic feedback of the position of the hydraulic cylinder through the follow-up of the valve sleeve, thereby disconnecting the mechanical connection between the valve core and the ball screw, and improving the reliability of the valve core. controlling. The valve core of the utility model is driven and controlled by a servo motor, and the valve sleeve is driven and controlled by a ball screw. By controlling the relative motion of the feedback valve sleeve and the valve core, the closed-loop digital control of the displacement of the digital hydraulic cylinder is realized.

Compared with the traditional digital hydraulic cylinder, the utility model has the following technical advantages:

(1) The control system is simple

The high-precision ball screw is used to realize the feedback control of the digital hydraulic cylinder, and the relative position of the valve core and the valve sleeve is used to control the opening of the valve, which does not require a complicated control system. Therefore, the control system is compared with ordinary digital hydraulic cylinders. simpler.

(2) High reliability

The fully mechanical high-precision feedback is used inside the digital hydraulic cylinder, which greatly improves the reliability of the internal transmission of the digital hydraulic cylinder and makes the hydraulic cylinder safe and reliable.

Description of drawings

Fig. 1 is a structural schematic diagram of a mechanical feedback digital hydraulic cylinder with a valve sleeve that can be moved.

FIG. 2 is a partially enlarged view of FIG. 1 .

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further:

As shown in Figure 1-2, the mechanical feedback digital hydraulic cylinder consists of servo motor 1, coupling 2, screw rod 3, valve core 4, sealing ring 5, valve front cover 6, valve sleeve 7, valve body 8, cylinder rear Cover 9, sealing ring 10, bearing 11, ball screw 12, screw nut 13, piston rod 14 and cylinder 15 are composed. The servo motor 1 is used to receive the pulse signal and transmit the rotary motion to the screw 3 through the coupling 2. The screw 3 is matched with the inner thread of the valve core close to the end of the servo motor 1. The valve core 4 is nested in the valve sleeve 7 and can be Sliding axially, the valve sleeve 7 is nested in the valve body 8 and can slide axially. The end of the valve sleeve 7 close to the cylinder body is provided with an internal thread and matches the external thread at the end of the ball screw 12. The screw nut 13 is fixed At one end of the piston rod 14 , the ball screw 12 is nested in the hollow piston rod 14 and can only perform rotational movement. Under the action of internal friction and external load, the piston rod 14 can only move in translation and cannot rotate. Both ends of the valve body 8 are fixedly connected to the cylinder rear cover 9 and the valve front cover 6 , the cylinder rear cover 9 is connected to the cylinder body 15 , and the valve front cover 6 is connected to the shell of the servo motor 1 . The end of the rodless chamber of the cylinder body 15 is provided with a bearing, and the bearing is axially fixed by the cylinder body 15 and the cylinder rear cover 9, and can only rotate, and is used to support the ball screw. The valve body 8 has an axial cylindrical hole for inserting the valve sleeve 7. The outer wall of the valve core 4 is provided with four bosses c, d, e, f, and the inner wall of the valve sleeve 7 is provided with valve The grooves corresponding to the four bosses of the core, the valve core 4 and the valve sleeve 7 cooperate to form a three-position four-way hydraulic valve, and the side wall of the valve body 15 is radially provided with oil passages corresponding to the three-position four-way hydraulic valve. Holes A, B, T, P, and the opening position of the oil passage hole on the side wall of the valve body are provided with axially expanding oil passage opening grooves, between each oil passage opening groove and between the oil passage opening groove and the end surface of the valve body are not connected to each other. The aperture of the oil passage opening groove is 3 times of the diameter of the oil passage through hole.

As shown in Figure 2, in the three-position four-way hydraulic valve composed of the valve core 4 and the valve sleeve 7, the axial arrangement of the valve sleeve 7 and the valve body 8 corresponds to the oil holes and oil ports of the T, A, P, and B ports in sequence. A cavity connected with port P is formed between the bosses d and e of the oil holes of the A and B ports corresponding to the spool 4 and the inner wall of the valve sleeve 7. Between the boss c and the boss d, the boss Between e and the boss f and the inner wall of the valve sleeve 7, a cavity communicating with the T interface is formed.

The specific working process of the digital hydraulic cylinder of the present utility model is as follows: first, a pulse signal is sent by the digital hydraulic cylinder control system, and the servo motor 1 starts to rotate after receiving the pulse signal, because the servo motor 1 is connected with the screw rod 3 through the shaft coupling 2, and The end of the spool 4 adjacent to the servo motor 1 has internal threads that cooperate with the screw 3 to cooperate with each other, the spool 4 can only move axially, so the screw 3 drives the spool 4 to move axially under the action of rotation. If the spool 4 moves to the left, the P port is connected with the A port, and the B port is connected with the T port. The high-pressure oil at the P port flows into the rodless chamber of the hydraulic cylinder through the A port, the rodless chamber is pressurized, the piston rod 14 moves to the left, and the oil in the rod chamber of the hydraulic cylinder flows back to the oil tank through the B and T ports.

When the piston rod 14 translates to the left, it drives the screw nut 13 fixed on the piston rod 14 to move to the left, the ball screw 12 does not move in the axial direction, and the ball screw 12 rotates in the opposite direction to the servo motor 1, because The ball screw 12 close to the external thread on the hydraulic valve matches the thread of the valve sleeve 7, the valve sleeve 7 can move axially, so under the action of rotation, the ball screw 12 valve sleeve 7 can move axially and move to the right, the valve The port is closed, and a stepping process ends.

Claims (5)

1. A mechanical feedback type digital hydraulic cylinder with movable valve sleeve is characterized in that it comprises a servo motor, a screw rod, a valve core, a valve sleeve, a valve body, a ball screw, a screw nut, a piston rod, and a cylinder body, The main shaft of the servo motor is connected to one end of the screw through a coupling, and the other end of the screw matches the internal thread of the valve core. The valve core is embedded in the valve sleeve, and the screw can drive the valve core to slide axially along the valve sleeve. In the valve body, the outer wall of the valve core is provided with a plurality of bosses, and the inner wall of the valve sleeve is provided with grooves corresponding to the bosses of the valve core. The valve core and the valve sleeve cooperate to form a three-position four-way hydraulic valve. The side wall of the body is radially provided with an oil passage hole corresponding to the three-position four-way hydraulic valve. The valve sleeve is provided with an internal thread near the end of the cylinder body to match the external thread at one end of the ball screw. Driven to slide along the axial direction of the valve body, the other end of the ball screw is embedded in the hollow piston rod, the screw nut is set on the piston of the piston rod, the ball screw can only rotate, and the piston rod is internally friction Under the action of force and external load, it can only do translational motion, but not rotation. 2. A mechanical feedback digital hydraulic cylinder with a movable valve sleeve according to claim 1, wherein both ends of the valve body are fixedly connected to the cylinder rear cover and the valve front cover, and the cylinder rear cover and the valve front cover are fixedly connected to each other. The cylinder body is connected, and the valve front cover is connected with the casing of the servo motor. 3. A mechanical feedback digital hydraulic cylinder with a valve sleeve that can be moved according to claim 2, characterized in that, the end of the rodless chamber of the cylinder body is provided with a bearing, and the bearing passes through the cylinder body and the cylinder back cover Axially fixed, only rotatable, used to support the ball screw. 4. A mechanical feedback digital hydraulic cylinder with a movable valve sleeve according to claim 1, characterized in that an axially expanding oil passage is provided at the opening of the oil passage hole on the side wall of the valve body The opening grooves are not connected to each other between each oil passage opening groove and between the oil passage opening groove and the end surface of the valve body. 5 . A mechanical feedback digital hydraulic cylinder with a followable valve sleeve according to claim 4 , wherein the diameter of the opening groove of the oil passage is three times the diameter of the through hole of the oil passage. 5 .