CN114593109A

CN114593109A - Oil cylinder buffer valve and hydraulic oil cylinder

Info

Publication number: CN114593109A
Application number: CN202210137003.4A
Authority: CN
Inventors: 邹婿邵; 段建辉; 吴云峰; 肖承丰
Original assignee: Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd
Current assignee: Hunan Zoomlion Intelligent Aerial Work Machinery Co Ltd
Priority date: 2022-02-15
Filing date: 2022-02-15
Publication date: 2022-06-07

Abstract

The invention belongs to the field of engineering hydraulic pressure and discloses an oil cylinder buffer valve and a hydraulic oil cylinder, wherein the oil cylinder buffer valve comprises a valve body, a throttling plunger and a pressure compensator, and the valve body is provided with a plunger cavity which is opened towards the first end of the valve body; the throttling plunger is a hollow plunger and can axially and slidably extend out of the plunger cavity towards the first end of the valve body, and a throttling groove is formed in the peripheral wall of the plunger of the throttling plunger; the pressure compensator is used for stabilizing the pressure difference between the front and the rear of the throttling groove. The oil cylinder buffer valve is embedded in an oil cylinder rodless cavity of the hydraulic oil cylinder in a piston shape, and the throttling plunger extends towards the oil cylinder piston of the hydraulic oil cylinder. In the hydraulic oil cylinder with the oil cylinder buffer valve, the buffer effect is not interfered by the load change of the oil cylinder, the oil passing area of the throttling port is smoothly changed, and the buffer process is smooth and has no impact; the throttling groove can be designed according to the buffering requirement; the oil cylinder buffer valve is detachably designed, the maintenance is convenient, the oil cylinder is not damaged in the dismounting process, and universal accessories of various specifications can be made and configured as required.

Description

Oil cylinder buffer valve and hydraulic oil cylinder

Technical Field

The invention belongs to the field of engineering hydraulic pressure, and particularly relates to an oil cylinder buffer valve and a hydraulic oil cylinder with the same.

Background

In the working process of the oil cylinder, in order to ensure the operation safety of equipment, the starting and braking of the oil cylinder are required to be soft, namely the flow of oil inlet and return of the oil cylinder is controllable, and the oil cylinder has a buffering function. Therefore, a sensor, a travel switch and the like can be arranged to generate signals for reflecting the working state, and the flow rate of the oil cylinder is adjusted by the electro-hydraulic control system according to the received state signals, so that the buffer control of the oil cylinder is realized, the equipment driven by the oil cylinder is safer and more comfortable in action, and the control performance is better. However, due to the structure or cost of some actuators, it is inconvenient to provide sensors, status detectors, etc., and the electronic control system is also inconvenient to control the flow of the cylinder, and at this time, the cylinder itself must be required to have a buffering function.

At present, the oil cylinder buffering can be basically divided into various types such as throttling buffering, oil-gas combined buffering, spring buffering, bypass shunting buffering and the like, but all have respective defects, for example, throttling flow is easily influenced by load pressure change, throttling flow is not adjustable, buffering effect is limited, service life is short, a buffering structure is easy to cause oil pollution, and the like.

Disclosure of Invention

Aiming at the defects or shortcomings in the prior art, the invention provides the oil cylinder buffer valve and the hydraulic oil cylinder, the oil cylinder buffer effect is not interfered by the load change of the oil cylinder, and the buffer process is stable and has no impact.

To achieve the above object, according to a first aspect of the present invention, there is disclosed a cylinder cushion valve, comprising:

the valve body is provided with a plunger cavity which is opened towards the first end of the valve body;

the throttling plunger is a hollow plunger and can axially and slidably extend out of the plunger cavity towards the first end of the valve body, and a throttling groove is formed in the peripheral wall of the plunger of the throttling plunger;

and the pressure compensator is used for stabilizing the front-back pressure difference of the throttling groove.

In some embodiments, the pressure compensator is a fixed-differential pressure-reducing valve arranged in the valve body, and control chambers at two ends of the fixed-differential pressure-reducing valve are respectively communicated with the front oil port and the rear oil port of the throttling groove.

In some embodiments, the first end of the valve body is provided with a first end valve body oil port and the second end of the valve body is provided with a second end valve body oil port, and the valve body is internally provided with a first inner communicating oil passage which extends inwards from the first end valve body oil port to the cavity peripheral wall of the plunger cavity;

the throttling plunger comprises a plunger contact end extending out of the first end of the valve body, a hollow plunger cavity of the throttling plunger is a hollow plunger oil duct, one end of the hollow plunger oil duct is closed by the plunger contact end, and the other end of the hollow plunger oil duct penetrates through an oil port of the valve body at the second end;

wherein the throttle groove on the plunger circumferential wall is formed as a throttle opening that communicates the first inner communication gallery with the hollow plunger gallery.

In some embodiments, a second inner oil passage extending from the first end valve body oil port to the through end of the hollow plunger oil passage is further formed in the valve body, and a check valve is arranged in the second inner oil passage and configured to allow the pressure oil to flow from the second end valve body oil port to the first end valve body oil port and to be blocked reversely.

In some embodiments, the choke is a thin-walled orifice, and the choke groove extends radially through and axially in the plunger circumferential wall, and the choke groove is configured such that the choke flow area gradually decreases as the throttle plunger slides axially inward toward the second end of the valve body.

In some embodiments, the throttle slot is a rectangular cross-section throttle slot or a triangular cross-section throttle slot.

In some embodiments, a return spring is disposed in the hollow plunger oil passage of the throttle plunger, one end of the return spring abuts against the plunger contact end, and the other end of the return spring extends out and is fixed toward the second end of the valve body.

In some embodiments, a third inner oil passage extending from the first end valve body oil port to the inside of the cavity peripheral wall of the plunger cavity is further formed in the valve body, a flow guide oil port radially aligned with the throttle groove is further formed in the plunger peripheral wall of the throttle plunger, and in the complete energy release position of the return spring, the inner end of the third inner oil passage is aligned with and communicated with the flow guide oil port.

In some embodiments, a plunger guide sleeve proximate to the first end of the valve body and a plunger guide track proximate to the second end of the valve body are embedded within the plunger cavity.

In some embodiments, a circumferential sealing groove is formed in the peripheral wall of the valve body, and a circumferential sealing ring is embedded in the circumferential sealing groove.

In some embodiments, the cylinder cushion valve comprises:

and the check valve is arranged at the second end of the valve body and is connected with the hollow plunger cavity of the throttling plunger.

In addition, according to a second aspect of the invention, a hydraulic oil cylinder is disclosed, wherein the hydraulic oil cylinder comprises the oil cylinder buffer valve, the oil cylinder buffer valve is embedded in an oil cylinder rodless cavity of the hydraulic oil cylinder in a piston shape, and the throttling plunger extends towards an oil cylinder piston of the hydraulic oil cylinder.

In some embodiments, the hydraulic cylinder comprises a fixedly arranged rodless cavity end cover and a detachably arranged rod cavity end cover, and the cylinder cushion valve can slide laterally from one end of the rod cavity end cover and move out of the cylinder barrel of the hydraulic cylinder.

In the oil cylinder buffer valve, a throttling buffering mode of the throttling plunger and a plunger type buffer valve structure are adopted, so that the oil cylinder buffer valve is simple in structure, more economical and practical, wider in application range, longer in service life, better in buffering effect and low in required processing precision, the throttling plunger is pushed by the piston to move, the throttling oil passing area of the throttling groove in the throttling plunger is gradually reduced, and the throttling buffering effect is realized; because the pressure compensator for stabilizing the front-back pressure difference of the throttling groove is integrated in the oil cylinder buffer valve, the throttling buffer effect is not interfered by the load change of the oil cylinder, and the buffer process is stable and has no impact.

Further advantages of the present invention, as well as the technical effects of preferred embodiments, are further described in the following detailed description.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram illustrating a structure of a cylinder cushion valve according to an embodiment of the present invention;

FIG. 2 is a right side view of the cylinder cushion valve shown in FIG. 1, illustrating an end surface of the first end of the valve body;

FIG. 3 is a left side view of the cylinder cushion valve shown in FIG. 1, illustrating an end surface of the second end of the valve body;

FIG. 4a shows an axial cross-sectional view of a throttle plunger with a rectangular throttle slot;

FIG. 4b is a cross-sectional view of the throttle plunger shown in FIG. 4 a;

FIGS. 4c and 4d are top views of the throttle plunger shown in FIG. 4a, but respectively showing rectangular throttle slots of different tapered shapes along the axial length direction;

FIG. 5a shows an axial cross-sectional view of a throttle plunger with a triangular throttle slot;

FIG. 5b is a cross-sectional view of the throttle plunger shown in FIG. 5 a;

FIG. 5c is a top view of the throttle plunger shown in FIG. 5a, illustrating the gradual change in the shape of the triangular throttle slot along the axial length;

FIG. 6 is a schematic structural diagram of a hydraulic cylinder according to an embodiment of the present invention, in which a cylinder cushion valve is embedded in a rodless cavity of the cylinder, a piston rod of the cylinder is shown in a fast retraction state, a throttling plunger is not in contact with a piston of the cylinder, and a return spring in the throttling plunger is in a complete energy release state;

FIG. 7 illustrates the direction of pressurized oil flow within a cylinder cushion valve in the hydraulic cylinder of FIG. 6;

FIG. 8 is a schematic structural diagram of a hydraulic cylinder according to an embodiment of the present invention, in which a cylinder cushion valve is embedded in a rodless cavity of the cylinder, a piston rod of the cylinder is shown in a retraction buffer state, a piston of the cylinder contacts and pushes a throttle plunger to move left, and a return spring in the throttle plunger is in a compressed energy storage state;

FIG. 9 illustrates the direction of flow of pressurized oil within a ram cushion valve in the hydraulic ram of FIG. 8; and

fig. 10 is a hydraulic schematic of a cylinder hydraulic system according to an embodiment of the present invention.

Description of the reference numerals

1 pressure compensator 2 check valve

3 throttling plunger 4 first balance valve core

5 second balanced spool 6 main valve

7 hydraulic oil cylinder 8 oil cylinder buffer valve

9 balance valve 10 one-way valve

11 valve body 12 plunger guide sleeve

13 compression nut 14 return spring

15 plunger guide rail 16 check valve disk seat

17 check valve core 18 check valve adjusting nut

19 circumferential sealing ring

20 first inner gallery 30 third inner gallery

40 second inner connecting oil passage 50 pilot oil passage

31 plunger contact end 32 hollow plunger oil passage

33 throttling groove 34 flow guide oil port

71 cylinder 72 oil cylinder piston

73 oil cylinder piston rod 74 rodless cavity end cover

75 rod cavity end cover 76 rodless cavity connecting oil port

77 rod cavity connecting oil port

101 first end valve body oil port 102 second end valve body oil port

111 first valve body end 112 second valve body end

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

The cylinder cushion valve and the hydraulic cylinder of the present invention will be described in detail with reference to the accompanying drawings in conjunction with the embodiments.

The invention firstly discloses an oil cylinder buffer valve. As shown in fig. 1 to 5c, in one embodiment, the cylinder cushion valve 8 includes:

a valve body 11 provided with a plunger cavity opening towards a first end 111 of the valve body;

the throttling plunger 3 is a hollow plunger and can axially and slidably extend out of the plunger cavity towards the first end 111 of the valve body, and a throttling groove 33 is formed in the plunger peripheral wall of the throttling plunger 3;

the pressure compensator 1 is used for stabilizing the pressure difference between the front and the rear of the throttling groove 33.

The oil cylinder buffer valve adopts a throttling buffering mode of a throttling plunger, and the throttle plunger 3 moves leftwards as shown in figure 1, so that the throttle hole flow area of a throttling groove 33 on the throttling plunger 3 is gradually reduced, and the oil flow of the oil cylinder is gradually changed. In particular, the cylinder cushion valve of the present invention is provided with the pressure compensator 1 for stabilizing the front-rear pressure difference of the orifice groove 33. Therefore, under the condition that the pressure difference between the front and the back of the throttling opening is basically stable, and under the condition that the oil pressure change between the front and the back of the throttling opening is large, the flow of overflowing the throttling opening is basically not influenced, in other words, the change of the external load when the oil cylinder works does not influence the throttling effect, so that the problem that the throttling flow is greatly influenced by the load pressure change of the oil cylinder in the existing variable throttling valve type oil cylinder buffering technology is solved, namely the throttling opening at the same position (namely the overflowing area of the throttling opening is not changed), the flow of overflowing the throttling opening is large when the front pressure of the oil opening of the throttling opening is large, and the flow is small when the pressure is small, so that the buffering speed of the oil cylinder is unstable, and the buffering effect of the oil cylinder is influenced.

Of course, the cylinder throttling buffer structure is not limited to the mode of adopting the throttling groove 33 on the throttling plunger 3, and a throttling groove such as a plunger ring gap can also be adopted, the buffer structure is simple and has low manufacturing cost, but in addition to the problem of being easily influenced by load pressure, the buffer structure can also generate friction due to the problem of processing precision concentricity, and therefore metal scraps and powder can cause great damage risk to a hydraulic system. The oil cylinder buffer structure adopting the oil-gas combination mode has good buffer effect, but has complex structure, large processing difficulty, higher cost and small application range due to poor economical efficiency. The oil cylinder buffer structure adopting the spring buffer principle is simple, but the service life, the buffer effect and the application occasion are limited.

Therefore, the oil cylinder cushion valve adopts a plunger type cushion valve structure which is simple in structure, more economical and practical, wider in application range, longer in service life and better in cushion effect, not only solves the problems of being easily affected by load pressure and unstable in cushion effect as described above, but also can further realize stable and continuous change of throttling flow through the design of the throttling groove, has no impact in the cushion process, has low required processing precision, has low probability of rubbing of parts, is convenient to disassemble and assemble and has better maintainability, and the following pertinence is further developed and explained.

As the name implies, the pressure compensator 1 functions to feed back and compensate pressure variation of the front port of the throttle groove 33 to the rear port of the throttle groove 33, thereby keeping the front-rear pressure difference stable. As will be understood by those skilled in the art, the pressure valve member for realizing such feedback of pressure difference change has various structural forms, for example, referring to fig. 10, in this embodiment, the pressure compensator 1 adopts a common constant-difference pressure-reducing valve, and two end control chambers of the constant-difference pressure-reducing valve are respectively communicated with front and rear oil ports of the throttling groove 33, so as to stabilize the front and rear pressure difference of the throttling groove 33. It should be noted that the functions and structures of the fixed-differential pressure reducing valve are well known to those skilled in the art, and are not described herein, and other types of pressure compensators are not described.

Referring to fig. 6, the cylinder cushion valve 8 of the present embodiment is configured to be mounted to a rodless cavity of a cylinder in a piston shape, so that the valve body 11 is in a cylindrical shape as shown in fig. 1, the two ends of the valve body 11 are a first valve body end 111 and a second valve body end 112, respectively, and the cylinder cushion valve 8 should be able to achieve throttling throughflow between the first valve body end 111 and the second valve body end 112.

To this end, as shown in fig. 2 and 3, as an example, the valve body first end 111 is provided with a first end valve body port 101 and the valve body second end 112 is provided with a second end valve body port 102. As shown in fig. 2, the first end valve body oil ports 101 in the first end 111 of the valve body are three, and are the end ports of the first inner oil gallery 20, the second inner oil gallery 40, and the third inner oil gallery 30 at the first end 111 of the valve body, but the invention is not limited thereto, and the first end valve body oil port 101 and the second end valve body oil port 102 may be one or more.

First, in the embodiment shown in fig. 1, the first inner communication oil passage 20 extending inward from the first end valve body oil port 101 to the cavity peripheral wall of the plunger cavity is formed in the valve body 11; then, the throttling plunger 3 comprises a plunger contact end 31 extending out of the first end 111 of the valve body, a hollow plunger cavity of the throttling plunger 3 is a hollow plunger oil passage 32, one end (the right end in fig. 1) of the hollow plunger cavity is closed by the plunger contact end 31, and the other end (the left end in fig. 1) of the hollow plunger cavity is communicated with a second-end valve body oil port 102; thus, the first inner communication oil passage 20 and the hollow plunger oil passage 32 constitute a throttling through-flow between the valve body first end 111 and the valve body second end 112; further, the throttle groove 33 on the plunger peripheral wall is formed as a throttle opening that communicates the first inner communication gallery 20 with the hollow plunger gallery 32.

Referring to fig. 6 and 10, a throttling through flow between the first end 111 and the second end 112 of the valve body is formed by the first inner communicating oil passage 20 and the hollow plunger oil passage 32, and oil in the rodless cavity of the cylinder sequentially passes through the pressure compensator 1 and the throttling plunger 3 in the first inner communicating oil passage 20 and the hollow plunger oil passage 32, so that buffering oil return is realized. When the rodless chamber of the cylinder is filled with oil to drive the piston rod 73 of the piston cylinder to extend, the pressure oil entering the rodless chamber through the rodless chamber connecting port 76 needs to penetrate through the valve body 11 and flow from the second end 112 of the valve body to the first end 111 of the valve body. For this purpose, a second inner oil passage 40 extending from the first port 101 to the through end of the hollow plunger oil passage 32 is further formed in the valve body 11, and a check valve 10 is disposed in the second inner oil passage 40, and the check valve 10 is configured to allow pressure oil to flow from the second port 102 to the first port 101 and to be cut off in the reverse direction. As shown in fig. 1 and 2, the check valve 10 and the second inner gallery 40 are also integrated in the valve body 11.

In order to realize the axial sliding of the hollow plunger in the plunger cavity, referring to fig. 1, a plunger guide sleeve 12 arranged near the first end 111 of the valve body and a plunger guide rail 15 arranged near the second end 112 of the valve body are embedded in the plunger cavity, and the end of the plunger guide sleeve 12 can be installed and fixed through a compression nut 13 and the like. Therefore, the inner end of the throttling plunger 3 extends into a plunger cavity in the valve body 11, and can axially slide along the plunger guide rail 15 through the accurate guiding of the plunger guide sleeve 12, so that the axial sliding process is more stable and smooth, and the change of the flow area of the throttling opening formed by the axial sliding of the throttling plunger 3 along with the throttling groove 33 is more smooth and stable, and can be estimated and designed.

In order to enable the throttle plunger 3 to slide axially and reset, a reset spring 14 is further arranged in the hollow plunger oil passage 32, one end of the reset spring 14 abuts against the plunger contact end 31, and the other end of the reset spring extends out of and is fixed towards the second end 112 of the valve body. Thus, when the oil cylinder piston 72 shown in fig. 6 moves rightwards to push the throttling plunger 3 to axially slide leftwards, the return spring 14 is in a pressurized energy storage state; when the oil cylinder piston 72 moves to the right to be disconnected with the plunger contact end 31, the compressed return spring 14 pushes the axial direction of the throttling plunger 3 to slide to the right until the full energy release state of the return spring 14 returns to the position of the maximum extending amount of the plunger contact end 31.

In the complete energy release state of the return spring 14, as shown in fig. 1, 4a, 6, and 7, at this time, no rod chamber returns oil, and in order to achieve a rapid oil return effect, a third inner communicating oil passage 30 is further particularly provided in the valve body 11, in which a first end valve body oil port 101 extends inward to the cavity peripheral wall of the plunger chamber, a flow guide oil port 34 radially aligned with the throttle slot 33 is further provided on the plunger peripheral wall of the throttle plunger 3, and at the complete energy release position of the return spring 14, the inner end of the third inner communicating oil passage 30 is aligned with the flow guide oil port 34 and is communicated. Thus, during quick oil return, the return oil can return through the first inner communicating oil passage 20 and the third inner communicating oil passage 30 connected in parallel, so as to meet the requirement of quick oil return, and the cylinder piston rod 73 can be quickly recovered.

In addition, because the oil cylinder buffer valve is used as a piston and is installed in the oil cylinder rodless cavity, in order to keep the oil liquid separation effect of the valve body flow, the peripheral wall of the valve body 11 can be provided with a peripheral sealing groove, and a peripheral sealing ring 19 is embedded in the peripheral sealing groove. The circumferential sealing ring 19 may be a combined sealing ring to obtain a better sealing effect, which is not described in detail herein.

In summary, the basic structure of the cylinder cushion valve of the present embodiment is basically explained. The pressure compensator 1 is arranged in the first inner communicating oil passage 20 in the valve body 11, referring to fig. 1 and 10, the control cavity at one end of the pressure compensator 1 is communicated with the first inner communicating oil passage 20 in front of the throttle groove 33, and the control cavity at the other end of the pressure compensator 1 is connected with the communicating end (i.e. the left end in the figure) of the hollow plunger oil passage 32 behind the throttle groove 33 through the pilot oil passage 50, so as to stabilize the pressure difference at two ends of the throttle groove 33, ensure that the throttle flow is only related to the opening degree of the throttle groove, and avoid the throttle flow from being influenced by the pressure change of the oil cylinder, for example, in the case of no pressure compensator 1, the load on the oil cylinder is large, the same throttle opening flow area is large, the flow flowing flow is increased, the buffering process is fast, and the buffering effect is reduced. On the contrary, when the load of the oil cylinder is small, the flow passing through the same throttling opening flow area is relatively small, the buffering process is slow, and the expected effect is not achieved.

Wherein, the throttling plunger 3 is arranged in the plunger guide sleeve 12 and can freely slide axially. Referring to fig. 6, after the cylinder cushion valve 8 is installed in the cylinder 71 of the hydraulic cylinder 7, the cylinder piston 72 can push the plunger contact end 31 of the throttle plunger 3, so as to push the throttle plunger 3 to move axially leftward. In the process of moving the throttle plunger 3 axially leftward, the throttle groove 33 moves axially leftward to gradually decrease the opening of the throttle groove, that is, the flow area of the throttle opening between the throttle groove 33 and the inner end of the first inner gallery 20 is gradually decreased, so as to achieve the oil-return throttling effect.

Referring to fig. 4a to 5c, on the plunger peripheral wall, a throttle groove 33 penetrates in the radial direction and extends in the axial direction, and the throttle groove 33 is provided such that the throttle orifice flow area gradually decreases as the throttle plunger 3 slides inward in the axial direction toward the valve body second end 112. In particular, according to the definition of the type of orifice in fluid mechanics, the orifice groove 33 provided in the plunger peripheral wall of the hollow plunger is a thin-walled orifice, and the through flow calculation formula is as follows:

in the formula:

q-flow (m)³/s)；

Mu-flow coefficient;

a-area of flow through the orifice (m)²)；

Δ p — differential pressure before and after choke (Pa);

rho-fluid Density (kg/m)³)。

Because the flow coefficient mu and the fluid density rho are basically close to be constant, as long as the pressure difference delta p before and after the throttling opening is ensured to be constant, the flow Q and the flow area A of the throttling opening are in linear proportional relation, namely the flow is only determined by the size of the throttling opening and is not influenced by other factors.

After the plunger contact end 31 of the throttling plunger 3 contacts the cylinder piston 72, the movement of the throttling plunger 3 is a smooth movement process along with the retraction of the cylinder piston 72, the area of the throttling groove is gradually reduced, the change is smooth, and therefore the whole speed reducing and buffering process of the cylinder is smooth and free of impact.

The throttling grooves 33 can be designed in various forms according to the buffering requirement, for example, rectangular throttling grooves, triangular throttling grooves and the like shown in fig. 4a to 4d and fig. 5a to 5c respectively, namely rectangular and triangular throttling groove cross sections shown in fig. 4d and fig. 5c, and the cross section shapes of other throttling grooves are not enumerated one by one.

Further, as the throttle plunger 3 slides inward in the axial direction, the rate of decrease in the throttle groove area is correlated with the throttle groove cross-sectional shape, shape change parameters, and the like, so that it is possible to achieve different buffering effects such as required constant acceleration buffering, variable acceleration buffering, and the like, by designing the parameters such as the shape design of the throttle groove 33, the throttle groove length, the throttle groove maximum width, minimum width, cross-sectional area change rate, and the like. For example, as shown in fig. 4b, a rectangular throttle groove may be provided with a groove width that is the same in the axial direction, or as shown in fig. 4c, the groove width of the rectangular throttle groove may be tapered in the axial direction, so that the rate of decrease in the throttle groove area is greater for fig. 4c than for the rectangular throttle groove of fig. 4b, and a desired acceleration buffering effect may be obtained.

Specifically, referring to fig. 1 and 10, the cylinder cushion valve 8 includes:

and the check valve 2 is arranged at the second end 112 of the valve body 11 and is connected with the hollow plunger cavity of the throttling plunger 3.

Specifically, the check valve 2 is disposed at the second end valve body oil port 102 of the valve body second end 112, and is communicated with the through end of the hollow plunger cavity of the throttle plunger 3. The inner end of the second inner gallery 40 provided with the check valve 10 may be connected between the check valve 2 and the through end of the hollow plunger cavity.

In fig. 1, the check valve 2 includes a check valve seat 16, a check valve core 17, and a check valve adjusting nut 18, and the check valve seat 16 is fixedly fitted to the second end valve body port 102 and has a valve port. The check valve 2 is in a normally open state, the check valve core 17 does not cover the valve port, and oil can smoothly flow through the check valve 2 from left to right or from right to left, but when the oil inlet flow at the left end of fig. 1 is large enough, the check valve core 17 can be pushed to move rightwards and close the valve port, so that the check valve 2 is closed, and the inner flow passage of the cylinder cushion valve 8 from the second end valve body oil port 102 to the first end valve body oil port 101 is closed. The check valve adjusting nut 18 is used for adjusting the front and rear pressure difference force of the check valve, which needs to be overcome before the valve core 17 of the check valve covers the valve port.

In the present embodiment, a common explosion-proof valve is used as the check valve 2. It will be appreciated by those skilled in the art that a check valve or the like of different back pressures may be used instead and will not be described further herein. After the check valve 2 is integrated in the oil cylinder buffer valve 8, the oil cylinder buffer valve 8 can be conveniently detached, so that the maintenance and replacement of the oil cylinder buffer valve 8 are facilitated, and the lower part is more specifically explained.

On the basis of the oil cylinder buffer valve 8, the invention also provides a hydraulic oil cylinder. As shown in fig. 6, the hydraulic cylinder 7 includes a cylinder cushion valve 8, the cylinder cushion valve 8 is embedded in the cylinder 71 in a piston shape, specifically, in the rodless cavity of the cylinder, and the throttle plunger 3 extends toward the cylinder piston 72 of the hydraulic cylinder 7. When pressure oil is introduced into the rod cavity connecting oil port 77 to recover the cylinder piston 72 and the cylinder piston rod 73, effective oil return buffering can be realized by installing the cylinder buffering valve 8. Moreover, the pressure compensator 1 is arranged in the oil cylinder buffer valve 8, so that the front-back pressure difference of the throttling opening can be stabilized, and the influence of pressure change on the buffer effect is avoided. By arranging the plunger type sliding throttling groove, the oil passing area of the throttling opening is changed more smoothly.

Wherein, the oil cylinder buffer valve 8 can be fixedly arranged, and can be conveniently disassembled and assembled by introducing pressure oil under the condition of integrating the check valve 2. Specifically, the hydraulic oil cylinder 7 comprises a fixedly arranged rodless cavity end cover 74 and a detachably mounted rod cavity end cover 75, and the oil cylinder buffer valve 8 can slide out of the cylinder barrel 71 of the oil cylinder from one side of the rod cavity end cover 75. Referring to fig. 10, in the process that pressure oil is fed into the rodless cavity of the hydraulic cylinder 7 to cause the cylinder piston rod 73 to extend rightward, the pressure oil flows to the end of the rodless cavity of the cylinder through the rodless cavity connecting oil port 76, namely flows to the second valve body end 112 of the cylinder cushion valve 8, when the flow of the pressure oil is large enough, the pressure oil can overcome the front-back pressure difference force of the check valve to push the valve core 17 of the check valve to close the valve port, the check valve 2 is closed, the inner flow passage of the cylinder cushion valve 8 is closed, and the pressure oil in the rodless cavity on the left side of the cylinder cushion valve 8 pushes the whole valve body 11 to move rightward, and the cylinder cushion valve 8 can be pushed to be taken out from the right end of the cylinder barrel 71 on the basis that the rod cavity end cover 75, the cylinder piston 72 and the cylinder piston rod 73 are removed in advance.

Thus, according to the detachable characteristic of the cylinder cushion valve 8, the cylinder cushion valve 8 and the cylinder 71 can be used as mutually matched universal accessories, and the maintainability is strong. Namely, the oil cylinder cushion valve 8 can be made into a corresponding prefabricated 'standard part' according to parameters such as the cylinder body material specification, the cushion stroke, the cushion curve and the like of the oil cylinder, can be configured as required, and has strong maneuverability and wide application range. For the oil cylinder and the application, the oil cylinder cushion valve 8 can be configured or cancelled according to the requirement, the oil cylinder is not damaged in the dismounting process, and the use and the maintenance are convenient.

Referring to fig. 10, in order to extend the cylinder piston rod 73 to the right, the solenoid coil a on the left side of the main valve 6 is powered first, and the hydraulic oil flows into the rodless cavity of the hydraulic cylinder 7 through the port P of the main valve 6, the check valve 2 and the check valve in the first balanced valve core 4 inside the balanced valve 9, so as to push the cylinder piston rod 73 to extend to the right. Meanwhile, the control oil opens the second balance valve core 5 in the balance valve 9, and the oil in the rod cavity of the oil cylinder flows back to the oil tank through the second balance valve core 5 and the T port of the main valve 6.

The oil cylinder cushion valve 8 is arranged inside the cylinder barrel 71 of the hydraulic oil cylinder 7 and can be used as a complete component, the oil cylinder cushion valve is plugged into the oil cylinder through a cylinder barrel opening of the oil cylinder and can slide inside the oil cylinder, the assembly and the disassembly are convenient, and the oil cylinder is not damaged. When the oil cylinder cushion valve 8 is not needed or the cushion effect needs to be changed, the oil cylinder piston 72 and the oil cylinder piston rod 73 can be detached from the right end of the cylinder barrel 71, a certain amount of oil flow exceeding the working flow is introduced into the oil cylinder rodless cavity through the rodless cavity connecting oil port 76, at the moment, the electromagnetic valve coil a on the left side of the main valve 6 is electrified, the hydraulic oil reaches the oil inlet of the check valve 2 through the P port of the main valve 6, when the flow exceeds the working flow and is larger than a certain value, a certain pressure difference is generated in front of and behind the check valve 2, when the pressure difference reaches a set value set by the check valve adjusting nut 18, the check valve 2 is closed, the oil liquid is gathered in the oil cylinder rodless cavity on the left side of the oil cylinder cushion valve 8, and the oil cylinder cushion valve 8 is pushed out from the cylinder barrel 71 to the right.

When the cylinder piston rod 73 retracts rapidly, as shown in fig. 6 and 7, before the cylinder piston 72 contacts the throttling plunger 3, the oil flows out sequentially through the first inner communicating oil passage 20, the pressure compensator 1, the third inner communicating oil passage 30, the throttling groove 33 and the flow guide oil port 34 of the throttling plunger 3, the inner cavity of the plunger guide rail 15 and the check valve 2 in the valve body 11 of the cylinder cushion valve 8, at this time, no throttling buffering is performed, and the flow path of the return oil in the valve body 11 of the cylinder cushion valve 8 is shown in fig. 7.

When the cylinder piston rod 73 continues to retract further, as shown in fig. 8, before the cylinder piston 72 contacts the throttling plunger 3, the oil flows out sequentially through the first inner communicating oil passage 20 of the valve body 11, the pressure compensator 1, the throttling slot of the throttling plunger 3, the inner cavity of the plunger guide rail 15 and the check valve 2, at this time, the oil guiding port 34 of the throttling plunger 3 is closed, the oil in the third inner communicating oil passage 30 is blocked, and the oil can only flow out through the pressure compensator 1 and the throttling slot 33 of the throttling plunger 3, so that throttling buffering is realized.

Due to the existence of the pressure compensator 1, in the process of realizing throttling buffering shown in the figures 8 and 9, the buffering effect is not interfered by the change of the oil cylinder load. Through the shape and parameter design of the throttling groove, the oil passing area of the throttling opening can be smoothly changed, and the buffering process is smooth and has no impact; the characteristics of the throttling groove can be individually designed according to buffering requirements such as buffering stroke, buffering speed, buffering acceleration and the like, and the application range is wide; the oil cylinder buffer valve 8 and the hydraulic oil cylinder 7 do not have the risk of system damage caused by scrap iron and other foreign matters generated by rubbing structural parts due to machining precision problems, and have long service life; the detachable design of the oil cylinder buffer valve 8 is convenient to maintain, the oil cylinder is not damaged in the dismounting process, a corresponding prefabricated standard part can be made according to the specification of the cylinder body material of the oil cylinder, and the oil cylinder can be configured as required and has strong maneuverability.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A cylinder cushion valve, characterized in that, the cylinder cushion valve (8) includes:

a valve body (11) provided with a plunger cavity opening towards a first end (111) of the valve body;

the throttling plunger (3) is a hollow plunger and can axially and slidably extend out of the plunger cavity towards the first end (111) of the valve body, and a throttling groove (33) is formed in the plunger peripheral wall of the throttling plunger (3);

a pressure compensator (1) for stabilizing the pressure difference across the throttle slot (33).

2. The oil cylinder buffer valve according to claim 1, wherein the pressure compensator (1) is a constant-differential pressure-reducing valve arranged in the valve body (11), and control cavities at two ends of the constant-differential pressure-reducing valve are respectively communicated with a front oil port and a rear oil port of the throttling groove (33).

3. The cylinder cushion valve according to claim 1, wherein the first end (111) of the valve body is provided with a first end valve body oil port (101) and the second end (112) of the valve body is provided with a second end valve body oil port (102), and a first inner communication oil passage (20) extending from the first end valve body oil port (101) inwards to the cavity peripheral wall of the plunger cavity is formed in the valve body (11);

the throttling plunger (3) comprises a plunger contact end (31) extending out of the first end (111) of the valve body, a hollow plunger cavity of the throttling plunger (3) is a hollow plunger oil duct (32), one end of the hollow plunger cavity is closed by the plunger contact end (31), and the other end of the hollow plunger cavity is communicated with the second end valve body oil port (102);

wherein the throttle groove (33) on the plunger circumferential wall is formed as a throttle opening that communicates the first inner communication oil passage (20) with the hollow plunger oil passage (32).

4. The cylinder cushion valve according to claim 3, wherein a second inner communication oil passage (40) extending from the first end valve body oil port (101) to the through end of the hollow plunger oil passage (32) is further formed in the valve body (11), a check valve (10) is disposed in the second inner communication oil passage (40), and the check valve (10) is configured to allow the pressure oil to flow from the second end valve body oil port (102) to the first end valve body oil port (101) and to be blocked reversely.

5. The cylinder cushion valve according to claim 3, wherein the orifice is a thin-walled orifice, and the orifice groove (33) is formed in the plunger circumferential wall so as to extend radially therethrough and axially, and the orifice groove (33) is formed so that an orifice flow area gradually decreases as the orifice plunger (3) slides axially inward toward the second end (112) of the valve body.

6. The cylinder cushion valve according to claim 5, wherein the throttle groove (33) is a rectangular cross-section throttle groove or a triangular cross-section throttle groove.

7. The cylinder cushion valve according to claim 3, characterized in that a return spring (14) is arranged in the hollow plunger oil passage (32) of the throttling plunger (3), one end of the return spring (14) abuts against the plunger contact end (31), and the other end of the return spring extends out and is fixed towards the second end (112) of the valve body.

8. The cylinder cushion valve according to claim 7, wherein a third inner communicating oil passage (30) extending from the first end valve body oil port (101) to the inner side of the cavity peripheral wall of the plunger cavity is further formed in the valve body (11), a flow guide oil port (34) radially aligned with the throttle groove (33) is further formed in the plunger peripheral wall of the throttle plunger (3), and in the fully released position of the return spring (14), the inner end of the third inner communicating oil passage (30) is aligned with and communicated with the flow guide oil port (34).

9. The cylinder cushion valve according to claim 1, characterized in that a plunger guide sleeve (12) near the first end (111) of the valve body and a plunger guide rail (15) near the second end (112) of the valve body are embedded in the plunger cavity.

10. The cylinder cushion valve according to claim 1, characterized in that the peripheral wall of the valve body (11) is provided with a circumferential sealing groove, and a circumferential sealing ring (19) is embedded in the circumferential sealing groove.

11. The cylinder cushion valve according to any one of claims 1 to 10, wherein the cylinder cushion valve (8) comprises:

the check valve (2) is arranged at the second end (112) of the valve body (11) and is connected with the hollow plunger cavity of the throttling plunger (3).

12. A hydraulic cylinder, characterized in that, hydraulic cylinder (7) includes according to any one of claims 1-11 the hydro-cylinder cushion valve (8), hydro-cylinder cushion valve (8) is the piston-like inlays adorn in the oil cylinder rodless chamber of hydraulic cylinder (7), throttle plunger (3) are towards the hydro-cylinder piston (72) of hydraulic cylinder (7) are stretched out.

13. A hydraulic ram according to claim 12, characterised in that the hydraulic ram (7) comprises a fixedly arranged rodless chamber end cap (74) and a detachably mounted rod chamber end cap (75), the ram cushion valve (8) being slidable out of the cylinder barrel (71) of the ram from the side of the rod chamber end cap (75).