CN216430083U

CN216430083U - Hydraulic control device for limiting mandrel of steel tube rolling mill

Info

Publication number: CN216430083U
Application number: CN202122885842.8U
Authority: CN
Inventors: 孙天健; 胡俊; 邓晓林; 李军; 魏航
Original assignee: CISDI Engineering Co Ltd
Current assignee: CISDI Engineering Co Ltd
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2022-05-03
Anticipated expiration: 2031-11-23

Abstract

The utility model discloses a steel pipe rolling mill plug restraint hydraulic control device, including connect the first hydraulic pressure oil control valve between the stopper chamber of pneumatic cylinder and oil supply, connect the second hydraulic pressure oil control valve between the stopper chamber of pneumatic cylinder and oil tank and connect the proportion choke valve between the pole chamber of pneumatic cylinder and oil supply. The device can be used for adjusting the stop speeds of different specifications by arranging the proportional throttle valve between the rod cavity of the hydraulic cylinder and the oil source, and can meet the controllable requirements of quick return and slow stop when the hydraulic cylinder retracts.

Description

Hydraulic control device for limiting mandrel of steel tube rolling mill

Technical Field

The utility model relates to a steel tube rolling mill plug retaining hydraulic control device.

Background

In the field of steel pipe rolling, a hollow billet punched by a puncher needs to be penetrated into a core rod before entering a rolling mill for rolling, and the core rod plays a role in supporting the inner wall of the hollow billet. In order to reduce the length of the mandrel, the advancing speed of the mandrel is smaller than the advancing speed of the hollow billet rolling, the action is called mandrel stopping, the advancing speed of the mandrel is called mandrel stopping speed, and the force applied to the mandrel in the opposite advancing direction is called mandrel stopping force. When the specifications of the hollow billets are different, the retaining speed of the core rods is also different, and the retaining speed of the core rods of the hollow billets with the same specifications is usually kept constant.

In the process of rolling the hollow billet, the hollow billet is subjected to metal deformation under the combined action of rotation and pressing of a mandrel and a roller of a rolling mill. Starting from the seizure of the tube into the steel, the mandrel advances at a fixed speed lower than the rolling speed of the steel tube. At this time, the mandrel bar is driven by the rolling force of the rolling mill, and if not limited, the mandrel bar advances synchronously with the steel pipe. In order to control the advancing speed of the mandrel, a motor or a hydraulic cylinder is usually adopted to give a certain force to the mandrel in the opposite direction of the rolling advancing, namely, the limited power of the mandrel, and the limited power of the mandrel varies from tens of tons to more than 100 tons according to different steel pipe specifications. Usually, a motor is used for long-distance mandrel restraint, and a hydraulic cylinder is used for short-distance mandrel restraint. The hydraulic control system for core rod restraint by adopting the hydraulic cylinder has the characteristics of large restraint force, long stroke of the oil cylinder, large cylinder diameter size, stable restraint speed, high retraction speed, large hydraulic flow and the like. The action process of the mandrel restraint under the action of the hydraulic cylinder is as follows:

1. the mandrel fast running motor drives the mandrel trolley and the mandrel to fast advance, so that the mandrel is inserted into the capillary and is limited and stopped at the position of the hydraulic stopper.

2. The hydraulic cylinder of the limiting device extends out at a set limiting speed, the quick mandrel operation motor adopts torque control to apply certain torque to the mandrel, the mandrel advances along with the extending speed of the hydraulic cylinder, and the hollow billet is bitten by the roller of the rolling mill to start rolling.

3. And applying a limiting force to the mandrel by a rod cavity of the hydraulic cylinder of the limiting device, so that the mandrel is not influenced by the rolling force and continues to extend at a limiting speed until the rolling of the hollow billet is finished.

4. The quick-operation motor drives the mandrel trolley and the mandrel to quickly return and is separated from the hydraulic stopper; and simultaneously, the restraint hydraulic cylinder also retracts rapidly, and the core rod and the restraint hydraulic cylinder are both in an initial state to wait for rolling of the next hollow billet.

From the process, the extending direction and the stress direction of the hydraulic cylinder are consistent in the process of the mandrel restraint, and the hydraulic cylinder is in a negative load state. At this point, the plug chamber of the restraining cylinder only needs to be replenished with oil, while the rod chamber needs to create a large back pressure to limit the speed of the cylinder. In the conventional design, because the pressure of a pump station is constant, when an oil cylinder extends, a plug cavity enters pressure oil, the extending direction of a hydraulic cylinder generates large pressure, and a horizontal component of rolling force is added, so that a high back pressure needs to be generated in a rod cavity to limit the speed of the hydraulic cylinder, and the energy consumption is high. Meanwhile, the core rod has larger limiting force, so that the cylinder diameter of the hydraulic cylinder is large, and in addition, the stretching speed is high, the flow of a hydraulic pump station is required to be large, and the installation power is very large.

The horizontal component of the force exerted by the roller on the mandrel during the period from the biting of the steel to the end of the rolling is not a constant force. On the contrary, this force varies from time to time due to the variation of the initial and final rolling speeds, the continuous decrease of the temperature of the hollow billet, the variation of the internal diameter of the hollow billet, and the like. Because the flow capacity changes when the pressure difference at the two ends of the fixed throttle valve is increased or decreased, the fixed throttle valve can not meet the speed requirement when the speed of the hydraulic cylinder is controlled to be a fixed value.

Therefore, aiming at the problems that the existing retained hydraulic cylinder has high energy consumption and the fixed throttle valve cannot meet the speed control requirement of the hydraulic cylinder, the developed steel tube rolling mill mandrel retained hydraulic control system which reduces the energy consumption in the operation process and meets the controllable speed extending and retracting requirements of the hydraulic cylinder is a technical problem to be solved urgently at present.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a steel tube rolling mill plug restraint hydraulic control device to solve fixed choke valve and can not satisfy pneumatic cylinder speed control requirement problem.

In order to solve the technical problem, the utility model provides a steel tube rolling mill plug retaining hydraulic control device, including connecting first hydraulic oil control valve between the stopper chamber of pneumatic cylinder and oil source, connecting second hydraulic oil control valve between the stopper chamber of pneumatic cylinder and oil tank and connecting the proportion choke valve between the pole chamber of pneumatic cylinder and oil source.

Furthermore, a pressure compensation unit for adjusting the pressure at two ends of the proportional throttle valve is connected between the rod cavity of the hydraulic cylinder and the proportional throttle valve, and the second hydraulic oil control valve and the proportional throttle valve are both connected with an oil source through a second one-way valve.

Further, the pressure compensation unit comprises a pressure compensator connected between a rod cavity of the hydraulic cylinder and the proportional throttle valve and a first check valve connected between a port A and a port B of the pressure compensator in parallel; the port A of the proportional throttle valve is respectively connected with the port A of the pressure compensator and the outlet end of the first check valve; the port B of the proportional throttle valve is respectively connected with the inlet end of the second one-way valve and the port Y of the pressure compensator; and the port B of the pressure compensator is respectively connected with the inlet end of the first one-way valve and the rod cavity of the hydraulic cylinder.

Further, the first hydraulic oil control valve and the second hydraulic oil control valve are both two-position two-way reversing valves.

The utility model has the advantages that: the proportional throttle valve is arranged between the rod cavity of the hydraulic cylinder and the oil source, so that the hydraulic cylinder can be used for adjusting the stop speeds of different specifications, and the controllable requirements of quick return and slow stop when the hydraulic cylinder retracts can be met.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Wherein: wherein: 1. a hydraulic cylinder; 2. a first two-position two-way directional valve; 3. a second two-position two-way directional valve; 4. a pressure compensator; 5. a first check valve; 6. a proportional throttle valve; 7. a second one-way valve.

Detailed Description

The hydraulic control device for mandrel restraint of a steel tube rolling mill shown in fig. 1 includes a first hydraulic oil control valve connected between a plug chamber of a hydraulic cylinder 1 and an oil source, a second hydraulic oil control valve connected between the plug chamber of the hydraulic cylinder 1 and an oil tank, and a proportional throttle valve 6 connected between a rod chamber of the hydraulic cylinder 1 and the oil source. The device can be used for adjusting the restraint speed of different specifications by arranging the proportional throttle valve 6 between the rod cavity of the hydraulic cylinder 1 and an oil source, and can meet the controllable requirements of quick return and slow stop when the hydraulic cylinder 1 retracts.

According to one embodiment of the application, a pressure compensation unit for adjusting the pressure at both ends of the proportional throttle valve 6 is connected between the rod cavity of the hydraulic cylinder 1 and the proportional throttle valve 6, and the second hydraulic oil control valve and the proportional throttle valve 6 are both connected with an oil source through a second check valve 7. The pressure compensation unit is used for balancing the horizontal component force of the rolling hollow billet of the roller and the cavity plugging pressure of the hydraulic cylinder 1 and fixing the pressure difference of the front end and the rear end of the proportional throttle valve 6, so that the requirement of stable limiting speed can be met without adjusting the proportional throttle valve 6 in real time in the limiting process.

According to one embodiment of the application, the pressure compensation unit comprises a pressure compensator 4 connected between the rod chamber of the hydraulic cylinder 1 and a proportional throttle 6, and a first check valve 5 connected in parallel between port a and port B of the pressure compensator 4; a port A of the proportional throttle valve 6 is respectively connected with a port A of the pressure compensator 4 and an outlet end of the first check valve 5; the port B of the proportional throttle valve 6 is respectively connected with the inlet end of the second one-way valve 7 and the port Y of the pressure compensator 4; the port B of the pressure compensator 4 is connected to the inlet end of the first check valve 5 and the rod chamber of the hydraulic cylinder 1, respectively. By arranging both the pressure compensator 4 and the proportional throttle 6 on the rod chamber side of the hydraulic cylinder 1, the specification of the hydraulic components can be reduced

According to an embodiment of the present application, the first hydraulic oil control valve and the second hydraulic oil control valve are both two-position two-way directional valves. The first two-position two-way reversing valve 2 connected between the plug cavity of the hydraulic cylinder 1 and the oil source can be used for communicating or disconnecting the plug cavity and the oil tank when the hydraulic cylinder 1 extends or retracts; a second two-position, two-way directional valve 3 connected between the plug chamber of the cylinder 1 and the tank may be used to connect or disconnect the plug chamber from the source P when the cylinder 1 is extended or retracted.

The working principle of the hydraulic control system for the mandrel restraint of the steel tube rolling mill is described in detail as follows:

in the preparation stage: the electromagnet YVH2 of the second two-position two-way reversing valve 3 is powered off and is in a right-position off state, and the electromagnet YVH1 of the first two-position two-way reversing valve 2 is powered on and is in a left-position on state. The pressure oil source P enters the rod cavity of the hydraulic cylinder 1 through the second one-way valve 7, the proportional throttle valve 6 and the first one-way valve 4, the hydraulic oil in the plug cavity of the hydraulic cylinder 1 flows back to the oil tank through the first two-position two-way reversing valve 2, and the hydraulic cylinder 1 is in a fully retracted state. The core rod is driven by the motor to rapidly penetrate into the capillary tube to reach the position of the limiting device and is limited by the movement speed of the hydraulic cylinder 1.

In the limiting stage: after the mandrel reaches the position of the retaining device, the hydraulic cylinder 1 extends out at the retaining speed, and the mandrel advances with the hydraulic cylinder 1 at the retaining speed under the limitation of the retaining device and the driving of the motor. The hollow billet enters a rolling mill to start rolling, and the core rod starts to receive the horizontal component force of the hollow billet rolled by the roller. In order to keep the flow rate of the proportional throttle 6 constant at the same given opening degree, a pressure compensator 5 is arranged in front of the proportional throttle 6, and the pressure difference between the front and the rear of the proportional throttle 6 is ensured not to be influenced by the outside. The pressure compensator 5 balances the sum of the horizontal component force of the rolling capillary of the roller and the cavity plugging pressure of the hydraulic cylinder 1, and the proportional throttle valve 6 controls the advancing speed of the hydraulic cylinder 1. At this stage, the electromagnet YVH2 of the second two-position two-way reversing valve 3 is energized and is in the left-position conducting state, and the electromagnet YVH1 of the first two-position two-way reversing valve 2 is de-energized and is in the right-position disconnecting state. The hydraulic oil flowing out of the rod cavity of the hydraulic cylinder 1 flows back through the pressure compensator 5 and the proportional throttle valve 6, and enters the plug cavity of the hydraulic cylinder 1 together with the pressure oil supplied by the oil source P through the second two-position two-way reversing valve 3 to form a differential circuit, so that the oil supply flow of the hydraulic oil source is reduced.

After the rolling is finished, the core rod is quickly retracted under the action of the core rod trolley and separated from the retaining device. Meanwhile, the hydraulic cylinder 1 of the limiting device also retracts rapidly at a certain speed and stops at a complete retraction position at a slow speed to wait for the rolling of the next hollow billet. At this stage, the electromagnet YVH2 of the second two-position two-way reversing valve 3 is powered off, the electromagnet YVH1 of the first two-position two-way reversing valve 2 is powered on, pressure oil enters the rod cavity of the hydraulic cylinder 1 through the proportional throttle valve 6 and the first check valve 4, and plug cavity hydraulic oil flows back to the oil tank through the first two-position two-way reversing valve 2. When retracting, the hydraulic cylinder 1 is free from other external force, and the speed is regulated and controlled by the proportional throttle valve 6.

Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A hydraulic control device for limiting a mandrel of a steel tube rolling mill is characterized by comprising a first hydraulic oil control valve connected between a plug cavity of a hydraulic cylinder and an oil source, a second hydraulic oil control valve connected between the plug cavity of the hydraulic cylinder and an oil tank, and a proportional throttle valve connected between a rod cavity of the hydraulic cylinder and the oil source.

2. The steel tube rolling mill mandrel retaining hydraulic control device according to claim 1, wherein a pressure compensation unit for adjusting the pressure at both ends of the proportional throttle valve is connected between the rod cavity of the hydraulic cylinder and the proportional throttle valve, and the second hydraulic oil control valve and the proportional throttle valve are both connected with an oil source through a second check valve.

3. The tube mill mandrel retaining hydraulic control device according to claim 2, wherein the pressure compensation unit includes a pressure compensator connected between a rod cavity of the hydraulic cylinder and the proportional throttle valve and a first check valve connected in parallel between port a and port B of the pressure compensator; the port A of the proportional throttle valve is respectively connected with the port A of the pressure compensator and the outlet end of the first check valve; the port B of the proportional throttle valve is respectively connected with the inlet end of the second one-way valve and the port Y of the pressure compensator; and the port B of the pressure compensator is respectively connected with the inlet end of the first one-way valve and the rod cavity of the hydraulic cylinder.

4. The hydraulic control device for mandrel restraint of a steel tube rolling mill according to claim 1, characterized in that the first hydraulic oil control valve and the second hydraulic oil control valve are both two-position two-way directional valves.