CN108443263B

CN108443263B - Hydraulic cylinder

Info

Publication number: CN108443263B
Application number: CN201810637408.8A
Authority: CN
Inventors: 陈启文; 唐文英
Original assignee: DONGGUAN DELISHI MACHINERY TECHNOLOGY CO LTD
Current assignee: DONGGUAN DELISHI MACHINERY TECHNOLOGY CO LTD
Priority date: 2018-06-20
Filing date: 2018-06-20
Publication date: 2023-08-18
Anticipated expiration: 2038-06-20
Also published as: CN108443263A

Abstract

The invention discloses a hydraulic cylinder, which comprises a cylinder body, an inner rod and a piston rod; the hydraulic oil with the first pressure is input into the quick cavity through the quick liquid inlet pipe and the quick channel so as to drive the piston rod to extend quickly in a displacement range needing to extend quickly; the hydraulic oil with the second pressure is input into the pressurizing cavity through the pressurizing channel and the pressurizing liquid inlet pipe, so that the output thrust of the piston rod is quickly increased, the piston rod is slowly stretched out, when the piston rod is about to be completely stretched out, the valve core moves along with the piston rod to be propped against the inner bottom wall of the cylinder body, the valve core moves upwards under the resistance action of the inner bottom wall of the cylinder body against the elasticity of the top spring and opens the pressure relief hole, the hydraulic oil with the second pressure in the pressurizing cavity flows into the pressure relief cavity through the transition cavity and the pressure relief hole, the thrust to the piston rod is quickly and automatically reduced, the pressure relief time of an electric and hydraulic system is saved, the stamping efficiency can be improved when the hydraulic oil is applied to a stamping machine, the structure of the stamping machine is simplified, and the corresponding transmission precision is improved.

Description

Hydraulic cylinder

Technical Field

The invention relates to the technical field of hydraulic transmission, in particular to a hydraulic cylinder.

Background

The hydraulic cylinder is an actuator in a hydraulic transmission system, which is an energy conversion device that converts hydraulic energy into mechanical energy. The hydraulic system has the characteristics of simple structure and reliable operation, can avoid a speed reducer when being used for realizing linear reciprocating motion, has no transmission clearance, stable motion and high transmission precision, and is widely applied to hydraulic systems of various machines.

However, the conventional hydraulic cylinder is affected by the factor that the switching of the output speed value and the thrust value is slow, and the application range is limited, for example, in the process of opening and closing the die, it is required that the upper die can be driven to provide different speeds and thrust for the upper die in different vertical area ranges, whereas the conventional hydraulic cylinder is affected by the factor that the switching of the output speed value and the thrust value is slow, and it takes a long time to achieve the requirement, so that the stamping efficiency is seriously affected (generally, only about ten times of opening and closing the die can be achieved in one minute).

Therefore, the existing punching machine mainly adopts a motor driving mode, namely, a motor drives a flywheel to move, and a transmission gear drives a crank connecting rod mechanism to enable a sliding block to move up and down through a clutch, so that an upper die is driven to lift, and the upper die and a lower die are matched to realize the punching forming of a metal plate. However, the structure of the punching machine is complicated by adopting a motor driving mode and adopting a flywheel, a speed reducing device and other mechanisms, and in addition, the transmission mode has the problems of relatively large transmission clearance and relatively low motion stability, and the corresponding transmission precision and the product forming quality are low.

Disclosure of Invention

The invention mainly aims to provide a hydraulic cylinder, which aims to improve the output speed of the hydraulic cylinder and the switching efficiency of thrust, so that the working efficiency is improved, and the application range is improved.

To achieve the above object, the present invention provides a hydraulic cylinder including:

the cylinder body is hollow in the cylinder body to form an accommodating space;

the inner rod is fixedly connected with the cylinder body, the upper part of the inner rod extends out of the accommodating space, and a first sealing structure is arranged at the matching surface of the inner rod and the cylinder body; and

the piston rod is limited with a cavity with an open top, the piston rod is movably sleeved on the inner rod and can axially move along the inner rod, a second sealing structure is arranged at the matching surface of the piston rod and the inner rod, a third sealing structure is arranged at the lower end of the inner rod 2 to divide the cavity into a return cavity and a quick cavity up and down, a fourth sealing structure is arranged on the peripheral wall of the piston rod to divide a clearance space between the piston rod and the cylinder body into a pressurizing cavity and a pressure relief cavity up and down, the lower part of the piston rod extends out of the cylinder body, a fifth sealing structure is arranged at the matching surface of the cylinder body and the piston rod, a quick channel communicated with the quick cavity is arranged at the part of the piston rod extending out of the cylinder body to be connected with a quick liquid inlet pipe, a return channel communicated with the return cavity is arranged at the part of the inner rod located outside the cylinder body to be connected with a return liquid inlet pipe, a pressure relief channel communicated with the pressure relief cavity is arranged at the position of the cylinder body corresponding to the pressurizing cavity, a transition cavity and a hole communicated with the pressure relief cavity and a pressure relief cavity are also arranged at the position of the pressure relief cavity corresponding to the pressurizing cavity, the pressure spring is arranged in the pressure relief cavity, the transition cavity and the pressure relief cavity are connected with a pressure spring hole, the top spring is arranged in the transition cavity and the pressure relief cavity is connected with the pressure cavity, when the valve core is completely extends out of the piston rod and the valve core is completely upwards through the valve core and the valve core when the valve core is completely and the valve core is completely stretched.

According to the technical scheme, a piston rod is sleeved at the part of an inner rod, which is positioned in an accommodating space of a cylinder body, a third sealing structure is arranged at the lower end of the inner rod to divide a cavity of the piston rod into a return cavity and a quick cavity up and down, a fourth sealing structure is arranged on the outer wall of the piston rod to divide a clearance space between the piston rod and the cylinder body into a pressurizing cavity and a pressure relief cavity up and down, and a valve core and a top spring are arranged in a transition cavity and a pressure relief hole which are communicated with the pressurizing cavity and the pressure relief cavity. In the process of driving the piston rod to extend to do work (such as stamping forming), firstly, controlling the oil pump to input hydraulic oil with first pressure into the quick cavity through the quick liquid inlet pipe and the quick channel through the servo control system so as to drive the piston rod to extend quickly in a displacement range (such as a displacement range when a plate to be stamped of the lower die is just stretched from a position of fully opening the die to the upper die) in need of extending quickly (it should be noted that in the displacement range, the resistance born by the piston rod is no or smaller, and the piston rod is suitable for adopting higher extending speed); then, the servo control system controls the oil pump to input hydraulic oil with a second pressure into the pressurizing cavity through the pressurizing channel and the pressurizing liquid inlet pipe so as to quickly increase the output thrust of the piston rod and enable the piston rod to slowly extend (it should be noted that in the stage, the piston rod is subjected to larger resistance and is required to slowly extend and output larger thrust, for example, the stage that the lower die just stretches the plate to be stamped until the plate to be stamped is about to be fully stretched); and then when the piston rod is about to extend completely, the valve core moves along with the piston rod to prop against the inner bottom wall of the cylinder body, the valve core moves upwards against the elastic force of the top spring under the action of the resistance of the inner bottom wall of the cylinder body and opens the pressure relief hole, so that hydraulic oil with second pressure in the pressurizing cavity flows into the pressure relief cavity through the transition cavity and the pressure relief hole, the thrust to the piston rod is reduced rapidly and automatically, the pressure relief time of an electric and hydraulic system is saved, and the piston rod extends completely (it should be noted that the stage is suitable for reducing the thrust and preventing overload). Obviously, the invention can greatly improve the switching efficiency of the output speed value and the thrust value, and can improve the punching efficiency when being applied to a punching machine (generally, the die opening and closing can be realized for about forty times in one minute). And the structure of the punching machine can be simplified, and the corresponding transmission precision can be improved.

Drawings

FIG. 1 is a schematic perspective view of the present invention;

FIG. 2 is a cross-sectional view of the present invention;

FIG. 3 is an enlarged detail view of portion A of FIG. 2;

FIG. 4 is a schematic view of a piston rod;

fig. 5 is a schematic view of the inner rod.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, in the embodiment of the present invention, directional indications (such as up, down, left, right, front, rear, top, bottom, inner, outer, vertical, lateral, longitudinal, counterclockwise, clockwise, circumferential, radial, axial … …) are referred to, and the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first" or "second" etc. in the embodiments of the present invention, the description of "first" or "second" etc. is only for descriptive purposes, and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

The invention provides a hydraulic cylinder.

In the embodiment of the present invention, as shown in fig. 1 to 5, the hydraulic cylinder includes a cylinder body 1, an inner rod 2, and a piston rod 3.

Wherein the interior of the cylinder 1 is hollow to form an accommodation space. The inner rod 2 is fixedly connected with the cylinder body 1, the upper part of the inner rod 2 extends out of the accommodating space, and a first sealing structure 21 is arranged at the matching surface of the inner rod 2 and the cylinder body 1. The piston rod 3 is limited with a cavity with an open top, the piston rod 3 is movably sleeved on the inner rod 2 and can move along the axial direction (or up and down) of the inner rod 2, a second sealing structure 31 is arranged at the matching surface of the piston rod 3 and the inner rod 2, a third sealing structure 22 is arranged at the lower end of the inner rod 2 to divide the cavity into a return cavity 32 and a quick cavity 33 up and down, a fourth sealing structure 34 is arranged on the peripheral wall of the piston rod 3 to divide the clearance space between the piston rod 3 and the cylinder body 1 into a pressurizing cavity 35 and a pressure relief cavity 36 up and down, the lower part of the piston rod 3 extends out of the cylinder body 1, a fifth sealing structure 111 is arranged at the matching surface of the cylinder body 1 and the piston rod 3, a quick channel 37 which is communicated with the quick cavity 33 is arranged at the part of the piston rod 3 extending out of the cylinder body 1 to be connected with a quick liquid inlet pipe (not shown), the part of the inner rod 2 positioned outside the cylinder body 1 is provided with a return channel 23 communicated with the return cavity 32 so as to be connected with a return liquid inlet pipe (not shown), the outer wall of the cylinder body 1 is provided with a pressure relief channel (not shown) communicated with a pressure relief cavity 36 so as to be connected with a pressure relief liquid outlet pipe (not shown), the position of the cylinder body 1 corresponding to the pressurizing cavity 35 is provided with a pressurizing channel 12 communicated with the pressurizing cavity 35 so as to be connected with the pressure inlet pipe (not shown), the piston rod 3 is also provided with a transition cavity 38 communicated with the pressurizing cavity 35 and a pressure relief hole 381 communicated with the transition cavity 38 and the pressure relief cavity 36, the transition cavity 38 is internally provided with a valve core 4 and a top spring 5, the upper part of the valve core 4 is elastically abutted against the top wall of the transition cavity 38 through the top spring 5, the lower part passes through the pressure relief hole 381 and stretches into the pressure relief cavity 36, when the piston rod 3 is not fully stretched out, the valve core 4 seals the pressure relief hole 381 under the elastic action of the top spring 5, and when the piston rod 3 is fully stretched out, the valve core 4 moves upward against the elastic force of the top spring 5 under the resistance of the inner bottom wall of the cylinder 1 and opens the pressure relief hole 381.

During the process of driving the piston rod 3 to extend to do work (for example, stamping forming), the oil pump is controlled by the servo control system to input hydraulic oil with a first pressure into the quick cavity 33 through the quick liquid inlet pipe (not shown) and the quick channel, so as to drive the piston rod 3 to extend quickly in a displacement range (for example, a displacement range from a fully opened position to a position when the lower die is just stretched by the upper die to be stamped (not shown)) where the resistance of the piston rod 3 is not or is smaller, and a higher extending speed is suitable to be adopted; then, the servo control system controls the oil pump to input the hydraulic oil having the second pressure into the pressurizing chamber 35 through the pressurizing liquid inlet pipe and the pressurizing passage 12 to rapidly increase the output thrust of the piston rod 3 and slowly extend the piston rod 3 (it should be noted that, in this stage, the piston rod 3 is subjected to a larger resistance, the piston rod 3 is required to slowly extend and output a larger thrust, for example, the stage that the lower die just stretches the sheet to be punched to be fully stretched; immediately after the piston rod 3 is about to be fully extended, the valve core 4 moves along with the piston rod 3 to abut against the inner bottom wall of the cylinder 1, the valve core 4 moves upward against the elastic force of the top spring 5 and opens the pressure relief hole 381 under the resistance of the inner bottom wall of the cylinder 1, so that the hydraulic oil with the second pressure in the pressurizing chamber 35 flows into the pressure relief chamber 36 through the transition chamber 38 and the pressure relief hole 381 and flows back to the oil tank through the pressure relief channel and the pressure relief liquid outlet pipe, so that the thrust to the piston rod 3 is quickly and automatically reduced, the pressure relief time of the electric and hydraulic system is saved, and the piston rod 3 is fully extended (it should be noted that this stage is suitable for reducing the thrust and preventing overload). Obviously, the invention can greatly improve the switching efficiency of the output speed value and the thrust value, and can improve the punching efficiency when being applied to a punching machine (generally, the die opening and closing can be realized for about forty times in one minute). And the structure of the punching machine can be simplified and the corresponding transmission precision can be improved. When the piston rod 3 needs to be contracted, the oil pump can be controlled to input hydraulic oil with third pressure into the return cavity through the return channel and the return liquid inlet pipe and push the piston rod 3 to be contracted, and the hydraulic oil of the pressurizing cavity 35 and the quick cavity 33 flows back to the oil tank until the piston rod 3 is contracted in place.

It should be noted that, the inlet end of the quick passage 37 is provided with a first joint 39 and is provided with a first hydraulic valve (not shown), the inlet of the first hydraulic valve is connected with an oil pump through the quick feed pipe, the outlet is connected with an oil tank (not shown) through an oil pipe, the inlet end of the return passage 23 is provided with a second joint 24 and is provided with a second hydraulic valve (not shown), the inlet of the second hydraulic valve is connected with the oil pump through the return feed pipe, and the outlet is connected with the oil tank (not shown) through the oil pipe; the inlet end of the pressurizing channel 12 is provided with a third joint 13 and is provided with a third hydraulic valve (not shown), the inlet of the third hydraulic valve is communicated with an oil pump through the pressurizing liquid inlet pipe (not shown), the outlet of the third hydraulic valve is connected with an oil tank (not shown) through an oil pipe, the first hydraulic valve, the second hydraulic valve and the third hydraulic valve are electrically connected with a servo control system, and the direction can be switched through the servo control system, for example, during the extending process of the piston rod 3, hydraulic oil in a return cavity can only flow out and can not flow in, the pressurizing cavity 35 and the quick cavity 33 can only flow in and can not flow out hydraulic oil, and during the contracting process of the piston rod 3, the reverse is carried out.

Specifically, the cylinder 1 includes a housing 10 and a guide sleeve 11, the housing 10 defines the accommodation space with an open bottom, the guide sleeve 11 is mounted at the open bottom of the housing 10 and sleeved on the piston rod 3, the fifth sealing structure 111 is mounted at the mating surface of the inner peripheral wall of the guide sleeve 11 and the piston rod 3 to prevent hydraulic oil from leaking out, and the sixth sealing structure 112 is disposed at the mating surface of the outer peripheral wall of the guide sleeve 11 and the cylinder 1 to prevent hydraulic oil from leaking out. Further, the bottom of the housing 10 has a radially extending flange 101, and the flange 101 is provided with a screw through hole to fasten the housing 10 to the base 100 by a screw to position the cylinder 1.

Specifically, the inner rod 2 is in a shaft shape with a small upper section and a large lower section, the step surface of the inner rod abuts against the inner top wall of the cylinder body 1, the upper section extends out of the shell 10 from a through hole formed in the top wall of the cylinder body 1, threads are formed on the outer peripheral wall of the part of the upper section extending out of the cylinder body 1, and the nut 6 is screwed on the upper section and abuts against the outer top wall of the cylinder body 1 so as to fasten the inner rod 2 to the cylinder body 1.

Specifically, the piston rod 3 includes a main body 30 and a sleeve body 301, the main body 30 defines the cavity with an open top, the sleeve body 301 is mounted at the open top and movably sleeved on the inner rod 2, the second sealing structure 31 is mounted at the mating surface of the inner peripheral wall of the sleeve body 301 and the inner rod 2 to perform a sealing function, and the seventh sealing structure 310 is mounted at the mating surface of the outer peripheral wall of the sleeve body 301 and the main body 30 to perform a sealing function.

Further, the cylinder 1 is provided with an oil compensating hole 14 communicating with the pressurizing cavity 35 at a position corresponding to the pressurizing cavity 35, the oil compensating hole 14 is connected with an oil compensating pump (not shown) through a hydraulic valve 7 and an oil pipe (not shown), when the hydraulic oil with the first pressure in the quick cavity 33 drives the piston rod 3 to extend, the space of the pressurizing cavity 35 is increased, the hydraulic oil needs to be supplemented to the pressurizing cavity 35 through the oil compensating pump through the hydraulic valve 7 and the oil compensating pipe, so that the pressurizing cavity 35 is kept full of the hydraulic oil, otherwise, in the subsequent process of inputting the hydraulic oil with the second pressure to the pressurizing cavity 35, the process of filling the pressurizing cavity 35 with the hydraulic oil with the second pressure is also needed, and the working efficiency is affected.

Specifically, the third sealing structure 22 includes a sleeve head 221 fixed (preferably screwed by screw-fit) to the lower end of the inner rod 2, and a sealing member 222, and the sealing member 222 is mounted to the outer peripheral wall of the sleeve head 221. More specifically, the seal comprises at least one rubber ring, the peripheral wall of the sleeve 221 being slotted and fitted with said rubber ring.

Specifically, as shown in fig. 4, the inlet end of the quick passage 37 is provided at the outer peripheral wall or bottom wall of the portion of the piston rod 3 located outside the cylinder 1, and extends to communicate with the cavity.

Specifically, as shown in fig. 5, the inlet end of the return channel 23 is preferably formed on the top wall of the inner rod 2, and the outlet end is formed on the side wall thereof and is in communication with the return chamber 32.

Specifically, each of the first sealing structure 21, the second sealing structure 31, the fourth sealing structure 34, the fifth sealing structure 111, the sixth sealing structure 112, and the seventh sealing structure 310 may include at least one rubber ring (for example, one, two, three or more), and the installation manner may also be a slotted installation manner.

It should be noted that the first pressure, the second pressure and the third pressure may be determined as desired, for example, the second pressure is preferably greater than the first pressure.

The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.

Claims

1. A hydraulic cylinder, comprising:

the piston rod is limited with a cavity with an open top, the piston rod is movably sleeved on the inner rod and can axially move along the inner rod, a second sealing structure is arranged at the matching surface of the piston rod and the inner rod, a third sealing structure is arranged at the lower end of the inner rod (2) so as to divide the cavity into a return cavity and a quick cavity up and down, a fourth sealing structure is arranged on the peripheral wall of the piston rod so as to divide a clearance space between the piston rod and the cylinder body into a pressurizing cavity and a pressure relief cavity up and down, the lower part of the piston rod extends out of the cylinder body, a fifth sealing structure is arranged at the matching surface of the cylinder body and the piston rod, a quick channel communicated with the quick cavity is arranged at the part of the piston rod extending out of the cylinder body so as to be connected with a return liquid inlet pipe, a pressure relief channel communicated with the pressure relief cavity is arranged at the outer wall of the cylinder body so as to be connected with the pressure relief liquid outlet pipe, a transition cavity communicated with the pressurizing cavity and a pressure relief cavity is arranged at the position of the cylinder body corresponding to the pressurizing cavity, a transition cavity and a pressure relief cavity communicated with a pressure relief cavity and a pressure relief cavity are also arranged at the position of the pressure relief cavity, the top spring is arranged at the transition cavity communicated with the pressure relief cavity, and the pressure relief cavity is arranged at the top wall, when the piston rod is completely extends out of the piston rod and the piston rod is completely upwards and is completely stretched out of the piston rod through the valve core when the piston rod and the piston rod is completely stretched out of the piston rod.

2. The hydraulic cylinder of claim 1, wherein: the inlet end of the quick passage is provided with a first connector and a first hydraulic valve, the inlet of the first hydraulic valve is connected with the oil pump through the quick liquid inlet pipe, the outlet of the first hydraulic valve is connected with the oil tank through an oil pipe, the inlet end of the return passage is provided with a second connector and a second hydraulic valve, the inlet of the second hydraulic valve is connected with the oil pump through the return liquid inlet pipe, and the outlet of the second hydraulic valve is connected with the oil tank through the oil pipe; the inlet end of the pressurizing channel is provided with a third joint and a third hydraulic valve, the inlet of the third hydraulic valve is communicated with the pressurizing liquid inlet pipe and the oil pump, the outlet of the third hydraulic valve is connected with the oil tank through an oil pipe, and the first hydraulic valve, the second hydraulic valve and the third hydraulic valve are electrically connected with the servo control system.

3. The hydraulic cylinder of claim 1, wherein: the cylinder body comprises a shell and a guide sleeve, wherein the shell is limited with an accommodating space with an open bottom, the guide sleeve is arranged at the open bottom of the shell and sleeved on the piston rod, the fifth sealing structure is arranged at the position of the matching surface of the inner peripheral wall of the guide sleeve and the piston rod, and the sixth sealing structure is arranged at the position of the matching surface of the outer peripheral wall of the guide sleeve and the cylinder body.

4. A hydraulic cylinder as claimed in claim 3, wherein: the bottom of the shell is provided with a radial extending flange, the flange is provided with a screw through hole, and the shell is fastened on the base through a screw.

5. The hydraulic cylinder of claim 1, wherein: the inner rod is in a stepped shaft shape with a small upper section and a large lower section, the stepped surface of the inner rod is propped against the top wall of the inner side of the cylinder body, the upper section extends out of the shell from a through hole formed in the top wall of the cylinder body, the outer peripheral wall of the part of the upper section extending out of the cylinder body is provided with threads, and a nut is screwed on the upper section and props against the top wall of the outer side of the cylinder body.

6. The hydraulic cylinder of claim 1, wherein: the piston rod comprises a main body and a sleeve body, wherein the main body is limited with a cavity with an opening at the top, the sleeve body is arranged at the opening at the top and movably sleeved on the inner rod, the second sealing structure is arranged at the position of the matching surface of the inner peripheral wall of the sleeve body and the inner rod, and the seventh sealing structure is arranged at the matching surface of the outer peripheral wall of the sleeve body and the main body.

7. The hydraulic cylinder of claim 1, wherein: the third sealing structure comprises a sleeve head fixedly arranged at the lower end of the inner rod and a sealing piece, wherein the sealing piece is arranged on the peripheral wall of the sleeve head and comprises at least one rubber ring, and the peripheral wall of the sleeve head is grooved and is provided with the rubber ring.

8. The hydraulic cylinder of claim 1, wherein: the inlet end of the rapid channel is arranged on the peripheral wall or the bottom wall of the part of the piston rod positioned outside the cylinder body and extends to be communicated with the cavity.

9. The hydraulic cylinder of claim 1, wherein: the inlet end of the return channel is arranged on the top wall of the inner rod, and the outlet end of the return channel is arranged on the side wall of the return channel and is communicated with the return cavity.

10. The hydraulic cylinder according to any one of claims 1 to 9, characterized in that: the cylinder body is provided with an oil supplementing hole communicated with the pressurizing cavity at the position corresponding to the pressurizing cavity, and the oil supplementing hole is connected with an oil supplementing pump through a hydraulic valve and an oil pipe.