Cylinder cushion valve and hydraulic cylinder

Abstract

The present invention belongs to the field of engineering hydraulics, and discloses a cylinder buffer valve and a hydraulic cylinder. The cylinder buffer valve includes a valve body, a throttling plunger and a pressure compensator. The valve body is provided with a plunger cavity opening toward the first end of the valve body; the throttling plunger is a hollow plunger and can axially slide out of the plunger cavity toward the first end of the valve body, and a throttling groove is provided on the plunger peripheral wall of the throttling plunger; the pressure compensator is used to stabilize the front and rear pressure difference of the throttling groove. The cylinder buffer valve is piston-shaped and embedded in the rodless cylinder cavity of the hydraulic cylinder, and the throttling plunger extends toward the cylinder piston of the hydraulic cylinder. In the hydraulic cylinder with the cylinder buffer valve of the present invention, the buffering effect is not affected by the change of the cylinder load, the oil flow area of ​​the throttling port changes smoothly, and the buffering process is smooth and impact-free; the throttling groove can be individually designed according to the buffering requirements; the cylinder buffer valve is detachable and easy to maintain, and the disassembly and assembly process does not damage the cylinder itself, and can be made into a universal accessory of multiple specifications and configured as needed.

Description

Technical Field

[0001] The invention belongs to the field of engineering hydraulics, and in particular relates to an oil cylinder buffer valve and a hydraulic oil cylinder having the oil cylinder buffer valve. Background Art

[0002] During the operation of the cylinder, in order to ensure the safe operation of the equipment, it is usually required that the cylinder's start and brake are both gentle, that is, the flow of oil inlet and return to the cylinder is controllable and has a buffering function. To this end, sensors, travel switches, etc. can be set to generate signals that reflect the working status, and the electro-hydraulic control system adjusts the flow in and out of the cylinder according to the received status signals, thereby achieving buffering control of the cylinder, making the cylinder-driven equipment safer, more comfortable, and better in control performance. However, due to structural or cost reasons, some actuators are not convenient to set sensors, status detection devices, etc., and the electronic control system is not convenient to intervene in the cylinder flow control. At this time, the cylinder itself must have a buffering function.

[0003] At present, cylinder buffers can basically be divided into throttling buffers, oil-gas combined buffers, spring buffers, bypass diversion buffers and other categories, but they all have their own shortcomings, such as throttling flow is easily affected by changes in load pressure, throttling flow is not adjustable, buffering effect is limited and life is short, buffer structure is easy to cause oil contamination, etc. Summary of the invention

[0004] In view of the above-mentioned defects or shortcomings of the prior art, the present invention provides a cylinder buffer valve and a hydraulic cylinder, the cylinder buffering effect of which is not affected by the change of cylinder load, and the buffering process is smooth and impact-free.

[0005] To achieve the above object, according to a first aspect of the present invention, a cylinder buffer valve is disclosed, the cylinder buffer valve comprising:

[0006] A valve body having a plunger cavity opening toward a first end of the valve body;

[0007] A throttling plunger is a hollow plunger and can axially slide out from the plunger cavity toward the first end of the valve body, and a throttling groove is provided on the plunger peripheral wall of the throttling plunger;

[0008] The pressure compensator is used to stabilize the pressure difference before and after the throttling groove.

[0009] In some embodiments, the pressure compensator is a differential pressure reducing valve disposed in the valve body, and control chambers at both ends of the differential pressure reducing valve are respectively connected to front and rear oil ports of the throttling groove.

[0010] 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 a first internally connected oil passage extending inwardly from the first end valve body oil port to the peripheral wall of the plunger cavity is formed in the valve body;

[0011] The throttling plunger comprises a plunger contact end extending out of the first end of the valve body, the hollow plunger cavity of the throttling plunger is a hollow plunger oil passage and one end is closed by the plunger contact end and the other end is connected to the second end valve body oil port;

[0012] Wherein, the throttling groove on the peripheral wall of the plunger is formed as a throttling port that connects the first internal connecting oil channel and the hollow plunger oil channel.

[0013] In some embodiments, a second internal connecting oil passage is also formed in the valve body and extends inward from the first end valve body oil port to the through end of the hollow plunger oil passage. A one-way valve is provided in the second internal connecting oil passage. The one-way valve is configured to allow pressure oil to flow from the second end valve body oil port to the first end valve body oil port and to block the flow in the reverse direction.

[0014] In some embodiments, the throttling port is a thin-walled orifice, and the throttling groove is radially penetrated and axially extended on the peripheral wall of the plunger, and the throttling groove is configured so that the flow area of ​​the throttling port gradually decreases as the throttling plunger slides axially inward toward the second end of the valve body.

[0015] In some embodiments, the throttling groove is a throttling groove with a rectangular cross-section or a throttling groove with a triangular cross-section.

[0016] In some embodiments, a return spring is provided in the hollow plunger oil passage of the throttling plunger, one end of the return spring abuts against the plunger contact end, and the other end extends toward and is fixed to the second end of the valve body.

[0017] In some embodiments, a third internal connecting oil passage is formed in the valve body and extends inward from the first end valve body oil port to the cavity peripheral wall of the plunger cavity. A guide oil port radially aligned with the throttling groove is also provided on the plunger peripheral wall of the throttling plunger. When the return spring is in the fully released energy position, the inner end of the third internal connecting oil passage is aligned and connected with the guide oil port.

[0018] In some embodiments, a plunger guide sleeve close to the first end of the valve body and a plunger guide rail close to the second end of the valve body are embedded in the plunger cavity.

[0019] In some embodiments, a circumferential sealing groove is provided on the outer peripheral wall of the valve body of the valve body, and a circumferential sealing ring is embedded in the circumferential sealing groove.

[0020] In some embodiments, the cylinder buffer valve comprises:

[0021] The check valve is arranged at the second end of the valve body and is connected to the hollow plunger cavity of the throttling plunger.

[0022] In addition, according to the second aspect of the present invention, a hydraulic cylinder is disclosed, which includes the above-mentioned cylinder buffer valve, and the cylinder buffer valve is piston-shaped and embedded in the cylinder rodless chamber of the hydraulic cylinder, and the throttling plunger extends toward the cylinder piston of the hydraulic cylinder.

[0023] In some embodiments, the hydraulic cylinder includes a fixed rodless cavity end cover and a detachably installed rod cavity end cover, and the cylinder buffer valve can slide out of the cylinder barrel of the cylinder from one side of the rod cavity end cover.

[0024] In the cylinder buffer valve of the present invention, a throttling buffering method of a throttling plunger and a plunger-type buffer valve structure are adopted, which has a simple structure, is more economical and practical, has a wider application range, a longer service life, and a better buffering effect. The required processing accuracy is not high. The throttling plunger is pushed to move by the piston, so that the throttling oil flow area of ​​the throttling groove on the throttling plunger is gradually reduced, thereby achieving a throttling buffering effect. Since a pressure compensator for stabilizing the front and rear pressure difference of the throttling groove is integrated in the cylinder buffer valve, the throttling buffering effect is not affected by changes in the cylinder load, and the buffering process is smooth and impact-free.

[0025] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 It is a schematic diagram of the composition structure of the oil cylinder buffer valve according to a specific embodiment of the present invention;

[0028] Figure 2 for Figure 1 The right side view of the cylinder cushion valve is shown, showing the end face of the first end of the valve body;

[0029] Figure 3 for Figure 1 The left side view of the cylinder cushion valve is shown, showing the end face of the second end of the valve body;

[0030] Figure 4a An axial cross-section cutaway view of a throttling plunger with a rectangular throttling slot is shown;

[0031] Figure 4b for Figure 4a A cross-sectional view of the throttle plunger is shown;

[0032] Figure 4c , Figure 4d Both Figure 4a A top view of the throttling plunger shown, but showing rectangular throttling grooves with different gradient shapes along the axial length direction;

[0033] Figure 5a An axial cross-section cutaway view of a throttling plunger with a triangular throttling groove is shown;

[0034] Figure 5b for Figure 5a A cross-sectional view of the throttle plunger is shown;

[0035] Figure 5c for Figure 5a The top view of the throttling plunger shown shows the gradual change in the shape of the triangular throttling groove along the axial length direction;

[0036] Figure 6 Schematic diagram of the structure of a hydraulic cylinder according to a specific embodiment of the present invention, wherein a cylinder buffer valve is embedded in the rodless cavity of the cylinder, the cylinder piston rod is in a fast retracted state, the throttling plunger is not in contact with the cylinder piston, and the return spring in the throttling plunger is in a fully released state;

[0037] Figure 7 Pictured Figure 6 The flow direction of the pressure oil in the cylinder buffer valve of the hydraulic cylinder;

[0038] Figure 8 Schematic diagram of the structure of a hydraulic cylinder according to a specific embodiment of the present invention, wherein a cylinder buffer valve is embedded in the rodless cavity of the cylinder, the cylinder piston rod is in a retracted buffer state, the cylinder piston contacts and pushes the throttling plunger to move left, and the return spring in the throttling plunger is in a compressed energy storage state;

[0039] Fig. 9 Pictured Figure 8 the flow direction of the pressure oil in the cylinder buffer valve in the hydraulic cylinder; and

[0040] Fig.10 The figure is a hydraulic principle diagram of a cylinder hydraulic system according to a specific embodiment of the present invention.

[0041] Description of Reference Numerals

[0042] 1 Pressure compensator 2 Check valve

[0043] 3 Throttle plunger 4 First balance valve core

[0044] 5 Second balance valve core 6 Main valve

[0045] 7 Hydraulic cylinder 8 Cylinder buffer valve

[0046] 9 Balance valve 10 Check valve

[0047] 11 Valve body 12 Plunger guide sleeve

[0048] 13 Compression nut 14 Return spring

[0049] 15 Plunger guide 16 Check valve seat

[0050] 17 Check valve core 18 Check valve adjusting nut

[0051] 19 Circumferential sealing ring

[0052] 20 first internally connected oil passage 30 third internally connected oil passage

[0053] 40 Second internal connecting oil passage 50 Pilot oil passage

[0054] 31 Plunger contact end 32 Hollow plunger oil passage

[0055] 33 Throttle groove 34 Oil guide port

[0056] 71 Cylinder 72 Cylinder piston

[0057] 73 Cylinder piston rod 74 Rodless cavity end cover

[0058] 75 Rod chamber end cover 76 Rodless chamber connection port

[0059] 77 Rod chamber connection port

[0060] 101 First end valve body oil port 102 Second end valve body oil port

[0061] 111 Valve body first end 112 Valve body second end DETAILED DESCRIPTION

[0062] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0063] The oil cylinder buffer valve and the hydraulic oil cylinder of the present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0064] The present invention application first discloses a cylinder buffer valve. Figures 1 to 5c As shown, in a specific embodiment, the cylinder buffer valve 8 includes:

[0065] The valve body 11 is provided with a plunger cavity opening toward a first end 111 of the valve body;

[0066] The throttling plunger 3 is a hollow plunger and can axially slide out from the plunger cavity toward the first end 111 of the valve body. A throttling groove 33 is provided on the plunger peripheral wall of the throttling plunger 3;

[0067] The pressure compensator 1 is used to stabilize the pressure difference before and after the throttling groove 33.

[0068] Among them, the oil cylinder buffer valve according to the present invention adopts a throttling buffering method of a throttling plunger. Figure 1 The throttle plunger 3 shown in the figure moves to the left, so that the throttle hole flow area of ​​the throttle groove 33 on the throttle plunger 3 gradually becomes smaller, thereby realizing the gradual change of the oil flow of the cylinder. In particular, a pressure compensator 1 for stabilizing the pressure difference before and after the throttle groove 33 is provided in the cylinder buffer valve of the present invention. In this way, when the pressure difference before and after the throttle port is basically stable, the flow rate of the throttle port is basically not affected when the oil pressure before and after the throttle port changes greatly. In other words, the change of the external load when the cylinder is working does not affect the throttling effect, thereby avoiding the problem that the throttle flow is greatly affected by the change of the cylinder load pressure in the existing variable throttle valve type cylinder buffer technology, that is, at the throttle port at the same position (that is, when the flow area of ​​the throttle port remains unchanged), when the pressure before the oil port of the throttle port is large, the flow rate of the throttle port is large, and when the pressure is small, the flow rate is small. In this case, the cylinder buffer speed will be unstable, affecting the cylinder buffer effect.

[0069] Of course, the oil cylinder throttling buffer structure is not limited to the throttling groove 33 on the throttling plunger 3, and can also adopt a throttling groove such as the plunger annular gap. This type of buffer structure is simple and has low manufacturing cost, but in addition to being susceptible to the problem of load pressure, it will also cause friction due to the problem of machining accuracy and concentricity, thereby generating metal debris and powder, which may cause great risk of damage to the hydraulic system. The oil cylinder buffer structure using the combination of oil and gas has a good buffering effect, but it has a complex structure, is difficult to process, and has a high cost. Due to its poor economy, its application range is very small. The oil cylinder buffer structure using the spring buffer principle is also relatively simple, but its service life, buffering effect and application occasions are limited.

[0070] To this end, the oil cylinder buffer valve according to the present invention adopts a plunger buffer valve structure with a simple structure, more economical and practical, wider application range, longer service life and better buffering effect. It not only solves the problem of being easily affected by load pressure and unstable buffering effect as mentioned above, but also can further achieve stable and continuous throttling flow rate changes through the design of the throttling groove. The buffering process is impact-free, the required processing accuracy is not high, the probability of collision of parts is not high, and it is easy to disassemble and assemble, and has good maintainability. The following will further elaborate on this.

[0071] As the name implies, the function of the pressure compensator 1 is to feed back the pressure change of the front oil port of the throttle groove 33 and compensate it to the rear oil port of the throttle groove 33, so as to keep the front and rear pressure difference stable. It can be understood by those skilled in the art that there are many structural forms of pressure valves that can realize such pressure difference change feedback. For example, see Fig.10 In this embodiment, the pressure compensator 1 adopts a common differential pressure reducing valve, and the control chambers at both ends of the differential pressure reducing valve are respectively connected to the front and rear oil ports of the throttle groove 33, so as to stabilize the front and rear pressure difference of the throttle groove 33. It should be noted that the function and structure of the differential pressure reducing valve are well known to those skilled in the art, and will not be described in detail here, and other forms of pressure compensators will not be described in detail.

[0072] See also Figure 6 The oil cylinder buffer valve 8 of this embodiment is used to be installed in the rodless chamber of the oil cylinder in the shape of a piston, so the valve body 11 is Figure 1 The cylindrical valve body 11 has two ends, namely a first end 111 and a second end 112 . The cylinder buffer valve 8 should be able to achieve throttling flow between the first end 111 and the second end 112 .

[0073] For this reason, Figure 2 , Figure 3 As shown, as an example, 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. Figure 2 In the first end 111 of the valve body shown, there are three first-end valve body oil ports 101, which are the end surface oil ports of the first internal connecting oil channel 20, the second internal connecting oil channel 40, and the third internal connecting oil channel 30 at the first end 111 of the valve body, but the present invention is not limited to this. The first-end valve body oil port 101 and the second-end valve body oil port 102 can be one or more, respectively.

[0074] First, in Figure 1 In the embodiment shown, a first internally connected oil passage 20 is formed in the valve body 11 and extends inwardly from the first end valve body oil port 101 to the cavity peripheral wall of the plunger cavity; then, the throttling plunger 3 includes a plunger contact end 31 extending out of the first end 111 of the valve body, and the hollow plunger cavity of the throttling plunger 3 is a hollow plunger oil passage 32 and one end ( Figure 1 The right end of the plunger is closed by the plunger contact end 31, and the other end ( Figure 1 The left end of the plunger) passes through to the second end valve body oil port 102; in this way, the first internal connecting oil channel 20 and the hollow plunger oil channel 32 constitute a throttling flow between the first end 111 of the valve body and the second end 112 of the valve body; furthermore, the throttling groove 33 on the peripheral wall of the plunger is formed as a throttling port that connects the first internal connecting oil channel 20 and the hollow plunger oil channel 32.

[0075] See also Figure 6 , Fig.10 , a throttling flow is formed between the first end 111 of the valve body and the second end 112 of the valve body through the first internal connecting oil passage 20 and the hollow plunger oil passage 32, and the oil in the rodless chamber of the cylinder passes through the pressure compensator 1 and the throttling plunger 3 in the first internal connecting oil passage 20 and the hollow plunger oil passage 32 in turn to realize buffered oil return. When oil enters the rodless chamber of the cylinder to drive the piston rod 73 of the active cylinder to extend, the pressure oil entering the rodless chamber through the rodless chamber connecting oil port 76 needs to pass 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. To this end, a second internal connecting oil passage 40 is also formed in the valve body 11, extending inward from the first end valve body oil port 101 to the through end of the hollow plunger oil passage 32, and a one-way valve 10 is provided in the second internal connecting oil passage 40. The one-way valve 10 is configured to allow pressure oil to flow from the second end valve body oil port 102 to the first end valve body oil port 101 and to cut off the reverse direction. Figure 1 , Figure 2 As shown, the one-way valve 10 and the second internal connecting oil passage 40 are also integrated in the valve body 11 .

[0076] To achieve axial sliding of the hollow plunger in the plunger cavity, see Figure 1 The plunger cavity is embedded with 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, and the end of the plunger guide sleeve 12 can be fixed by a clamping nut 13 or the like. In this way, the inner end of the throttling plunger 3 extends into the plunger cavity in the valve body 11, and can slide axially along the plunger guide rail 15 through the precise guidance of the plunger guide sleeve 12, so that the axial sliding process is more stable and smooth, and then the change of the throttling port flow area formed by the throttling groove 33 following the axial sliding of the throttling plunger 3 is also smoother, more stable, predictable and designable.

[0077] In order to reset the axial sliding of the throttling plunger 3, a reset spring 14 is further provided 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 extends toward the second end 112 of the valve body and is fixed. Figure 6 When the cylinder piston 72 shown moves to the right to push the throttling plunger 3 to slide axially to the left, the return spring 14 is in a compressed energy storage state; when the cylinder piston 72 moves to the right to disconnect from the plunger contact end 31, the compressed return spring 14 pushes the throttling plunger 3 to slide axially to the right until the return spring 14 is completely released and returns to the position of the maximum extension of the plunger contact end 31.

[0078] When the return spring 14 is fully released, Figure 1 , Figure 4a , Figure 6 , Figure 7As shown, at this time, there is no rod cavity oil return. In order to achieve the effect of rapid oil return, the valve body 11 is also specially provided with a first end valve body oil port 101 extending inward to the third internal connecting oil channel 30 on the cavity wall of the plunger cavity. The plunger wall of the throttling plunger 3 is also provided with a guide oil port 34 radially aligned with the throttling groove 33. In the full energy release position of the return spring 14, the inner end of the third internal connecting oil channel 30 is aligned and connected with the guide oil port 34. In this way, when the oil is quickly returned, the return oil can be returned through the parallel first internal connecting oil channel 20 and the third internal connecting oil channel 30, which meets the need for rapid oil return and enables the cylinder piston rod 73 to be quickly recovered.

[0079] In addition, since the oil cylinder buffer valve is installed in the rodless cavity of the oil cylinder as a piston, in order to maintain the oil separation effect of the valve body flow, the outer peripheral wall of the valve body 11 can be provided with a circumferential sealing groove, and a circumferential sealing ring 19 is embedded in the circumferential sealing groove. Among them, the circumferential sealing ring 19 can adopt the structural form of a combined sealing ring to obtain a better sealing effect, which will not be described in detail here.

[0080] In summary, the basic structure of the cylinder buffer valve of this embodiment is basically described. The pressure compensator 1 is arranged in the first internal connecting oil passage 20 in the valve body 11, see Figure 1 , Fig.10 The control chamber at one end of the pressure compensator 1 is connected to the first internal oil channel 20 before the throttling groove 33, and the control chamber at the other end of the pressure compensator 1 is connected to the through end (i.e., the left end in the figure) of the hollow plunger oil channel 32 after the throttling groove 33 through the pilot oil passage 50, thereby stabilizing the pressure difference at both ends of the throttling groove 33, ensuring that the throttling flow is only related to the throttling groove opening, and avoiding the throttling flow from being affected by the cylinder pressure change. For example, in the absence of the pressure compensator 1, the load on the cylinder is large, and the flow rate will increase for the same throttling port flow area, then the buffering process will become faster, and the buffering effect will be discounted. On the contrary, if the cylinder load is small, the flow rate will be relatively small for the same throttling port flow area, and the buffering process will be slower, which is not the desired effect.

[0081] The throttling plunger 3 is installed in the plunger guide sleeve 12 and can slide freely in the axial direction. Figure 6 After the oil cylinder buffer valve 8 is installed in the cylinder barrel 71 of the hydraulic oil cylinder 7, the oil cylinder piston 72 can push the plunger contact end 31 of the throttle plunger 3, thereby pushing the throttle plunger 3 to move axially to the left. During the axial leftward movement of the throttle plunger 3, the throttle groove 33 follows the axial leftward movement and the throttle groove opening gradually decreases, that is, the throttle opening flow area between the throttle groove 33 and the inner end of the first internal connecting oil channel 20 is gradually reduced to achieve the return oil throttling effect.

[0082] See also Figures 4a to 5c, on the plunger peripheral wall, the throttling groove 33 penetrates radially and extends axially, and the throttling groove 33 is configured such that the flow area of ​​the throttling port gradually decreases as the throttling plunger 3 slides axially inward toward the second end 112 of the valve body. In particular, according to the definition of the throttling port type in fluid mechanics, the throttling groove 33 provided on the plunger peripheral wall of the hollow plunger is a thin-walled orifice, and the flow rate calculation formula thereof is as follows:

[0083]

[0084] Where:

[0085] Q——Flow (m 3 / s);

[0086] μ——discharge coefficient;

[0087] A——Throttle flow area (m 2 );

[0088] Δp——pressure difference before and after the throttle (Pa);

[0089] ρ——Fluid density (kg / m 3 ).

[0090] Because the flow coefficient μ and fluid density ρ are basically close to constants, as long as the pressure difference Δp before and after the throttle is kept constant, the flow rate Q and the flow area A of the throttle are in linear proportion, that is, the flow rate is only determined by the size of the throttle and is not affected by other factors.

[0091] After the plunger contact end 31 of the throttling plunger 3 contacts the cylinder piston 72, the cylinder piston 72 retracts. During this process, the movement of the throttling plunger 3 is a smooth movement process, the throttling groove area gradually decreases, and its change is also smooth. Therefore, the entire deceleration and buffering process of the cylinder is also smooth and impact-free.

[0092] The throttling groove 33 can be designed in various forms according to the buffering requirements, for example Figures 4a to 4d , Figure 5a to Figure 5c The rectangular throttling groove, triangular cross-section throttling groove, etc. shown in FIG. Figure 4d , Figure 5c The rectangular and triangular throttling groove cross-sections are shown, and other throttling groove cross-section shapes are not listed one by one.

[0093] Furthermore, as the throttle plunger 3 slides axially inward, the decreasing rate of the throttle groove area is related to the cross-sectional shape of the throttle groove, shape change parameters, etc. Therefore, different buffering effects such as constant acceleration buffering and variable acceleration buffering can be achieved by designing the shape of the throttle groove 33, the length of the throttle groove, the maximum width of the throttle groove, the minimum width, the cross-sectional area change rate, and other parameters. Figure 4bAs shown, the rectangular throttling groove can be configured to have a groove width that is equal in the axial direction, or as shown in Figure 4c As shown in the figure, the width of the rectangular throttling groove gradually decreases along the axial direction, so Figure 4c Relative to Figure 4b For the rectangular throttle groove, the decreasing rate of the throttle groove area is larger, and the required acceleration buffering effect can be obtained.

[0094] In particular, see Figure 1 , Fig.10 , the oil cylinder buffer valve 8 comprises:

[0095] The check valve 2 is arranged at the second end 112 of the valve body 11 and is connected to the hollow plunger cavity of the throttling plunger 3 .

[0096] Specifically, the check valve 2 is arranged at the second end valve body oil port 102 of the second end 112 of the valve body, and communicates with the through end of the hollow plunger cavity of the throttling plunger 3. The inner end of the second internal connecting oil passage 40 provided with the one-way valve 10 can be connected between the check valve 2 and the through end of the hollow plunger cavity.

[0097] exist Figure 1 In the embodiment, the check valve 2 includes a check valve seat 16, a check valve core 17 and a check valve adjusting nut 18. The check valve seat 16 is fixedly mounted at the oil port 102 of the second end valve body and is provided with a valve port. The check valve 2 is in a normally open state, and the check valve core 17 does not cover the valve port. The oil can flow smoothly from left to right or from right to left through the check valve 2, but Figure 1 When the oil inlet flow rate at the left end is large enough, the check valve core 17 can be pushed to the right and close the valve port, so that the check valve 2 is cut off, thereby cutting off the inner flow channel of the cylinder buffer valve 8 from the second end valve body oil port 102 to the first end valve body oil port 101. The check valve adjusting nut 18 is used to adjust the pressure difference force before and after the check valve that needs to be overcome before the check valve core 17 covers the valve port.

[0098] In this embodiment, the check valve 2 adopts a common explosion-proof valve. It can be understood by those skilled in the art that a one-way valve with different back pressures can also be used as a substitute, which will not be described in detail here. After the check valve 2 is integrated into the cylinder buffer valve 8, the cylinder buffer valve 8 can be easily disassembled, thereby facilitating the maintenance and replacement of the cylinder buffer valve 8, which will be described in more detail below.

[0099] Based on the above-mentioned cylinder buffer valve 8, the present invention also provides a hydraulic cylinder. Figure 6As shown, the hydraulic cylinder 7 includes a cylinder buffer valve 8, which is piston-shaped and embedded in the cylinder barrel 71, specifically in the rodless chamber of the cylinder, and the throttling plunger 3 extends toward the cylinder piston 72 of the hydraulic cylinder 7. When the rod chamber connecting oil port 77 is passed through the pressure oil, when the cylinder piston 72 and the cylinder piston rod 73 are recovered, effective return oil buffering can be achieved by installing the cylinder buffer valve 8. Moreover, by providing a pressure compensator 1 in the cylinder buffer valve 8, the pressure difference before and after the throttle port can be stabilized to prevent the buffering effect from being affected by pressure changes. By providing a plunger-type sliding throttling groove, the oil flow area of ​​the throttle port changes more smoothly.

[0100] The oil cylinder buffer valve 8 can be fixedly arranged, or can be conveniently disassembled and assembled by introducing pressure oil when the check valve 2 is integrated. Specifically, the hydraulic oil cylinder 7 includes a fixedly arranged rodless cavity end cover 74 and a detachably installed 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. Fig.10 In the process of pressure oil entering the rodless chamber of the hydraulic cylinder 7 to prompt the cylinder piston rod 73 to extend to the right, the pressure oil first flows to the end of the rodless chamber of the cylinder through the rodless chamber connecting oil port 76, that is, it flows to the second end 112 of the valve body of the cylinder buffer valve 8. When the flow rate of the pressure oil is large enough, it can overcome the pressure difference force before and after the check valve and push the check valve core 17 to cover the valve port, the check valve 2 is cut off, and the internal flow channel of the cylinder buffer valve 8 is cut off, and then the pressure oil in the left rodless chamber of the cylinder buffer valve 8 will push the entire valve body 11 to move to the right. On the basis of pre-removing the rod chamber end cover 75, the cylinder piston 72, and the cylinder piston rod 73, the cylinder buffer valve 8 can be pushed out from the right end of the cylinder barrel 71.

[0101] In this way, according to the detachable characteristics of the oil cylinder buffer valve 8, the oil cylinder buffer valve 8 and the cylinder barrel 71 can be used as universal accessories that match each other, and the maintainability is strong. That is, the oil cylinder buffer valve 8 can be made into a corresponding prefabricated "standard part" according to the cylinder material specifications, buffer stroke, buffer curve and other parameters of the oil cylinder, which can be configured as needed, has strong mobility and a wide range of adaptability. For the oil cylinder and application, the oil cylinder buffer valve 8 can be configured or cancelled as needed, and the disassembly process does not damage the oil cylinder itself, which is convenient for use and maintenance.

[0102] See also Fig.10 To make the cylinder piston rod 73 extend to the right, first energize the solenoid valve coil a on the left side of the main valve 6, and the hydraulic oil flows into the rodless chamber of the hydraulic cylinder 7 through the P port of the main valve 6, the check valve 2, and the one-way valve in the first balancing valve core 4 inside the balancing valve 9, pushing the cylinder piston rod 73 to extend to the right. At the same time, the control oil opens the second balancing valve core 5 inside the balancing valve 9, and the oil in the rod chamber of the cylinder flows back to the oil tank through the second balancing valve core 5 and the T port of the main valve 6.

[0103] The oil cylinder buffer valve 8 is placed inside the cylinder barrel 71 of the hydraulic oil cylinder 7, and can be used as a complete component. It can be inserted into the oil cylinder through the cylinder barrel port of the oil cylinder, and can slide inside the oil cylinder. It is easy to assemble and disassemble without damaging the oil cylinder itself. When the oil cylinder buffer valve 8 is not needed or the buffering effect needs to be changed, the oil cylinder piston 72 and the oil cylinder piston rod 73 can be removed from the right end of the cylinder barrel 71, and a certain amount of oil flow exceeding the working flow is introduced into the rodless cavity of the oil cylinder through the rodless cavity connecting oil port 76. At this time, the solenoid valve coil a on the left side of the main valve 6 is energized, and 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 greater than a certain value, a certain pressure difference is generated before and after the check valve 2. When the pressure difference force reaches the set value set by the check valve adjusting nut 18, the check valve 2 is closed, and the oil gathers in the rodless cavity of the oil cylinder on the left side of the oil cylinder buffer valve 8, and then the oil cylinder buffer valve 8 is pushed out to the right from the cylinder barrel 71.

[0104] When the oil cylinder piston rod 73 is quickly retracted, as shown in FIG. Figure 6 , Figure 7 As shown, before the cylinder piston 72 contacts the throttling plunger 3, the oil flows out in sequence through the first internal connecting oil passage 20 in the valve body 11 of the cylinder buffer valve 8, the pressure compensator 1, the third internal connecting oil passage 30, the throttling groove 33 of the throttling plunger 3 and the guide oil port 34, the inner cavity of the plunger guide rail 15, and the check valve 2. At this time, there is no throttling buffer, and the flow path of the return oil in the valve body 11 of the cylinder buffer valve 8 is as shown in FIG. Figure 7 shown.

[0105] When the oil cylinder piston rod 73 continues to retract further, as shown in FIG. Figure 8 As shown, before the cylinder piston 72 contacts the throttling plunger 3, the oil flows out in sequence through the first internal connecting oil passage 20 of the valve body 11, the pressure compensator 1, the throttling groove of the throttling plunger 3, the inner cavity of the plunger guide rail 15, and the check valve 2. At this time, the guide oil port 34 of the throttling plunger 3 is closed, and the oil in the third internal connecting oil passage 30 is blocked. The oil can only flow out through the pressure compensator 1 and the throttling groove 33 of the throttling plunger 3, thereby realizing throttling buffering.

[0106] Due to the presence of the pressure compensator 1, the above Figure 8 , Fig. 9In the process of realizing throttling buffering as shown, the buffering effect is not affected by the change of cylinder load. Through the shape and parameter design of the throttling groove, the oil flow area of ​​the throttling port can be changed smoothly, and the buffering process can be smooth and impact-free; the characteristics of the throttling groove can be designed according to the buffering requirements such as buffering stroke, buffering speed, buffering acceleration, etc., and have a wide range of adaptability; the cylinder buffer valve 8 and the hydraulic cylinder 7 of the present invention do not have the risk of foreign matter such as iron filings caused by the collision of structural parts due to processing accuracy problems, causing damage to the system, and have a long service life; the detachable design of the cylinder buffer valve 8 makes maintenance convenient, and the disassembly process does not damage the cylinder itself. It can be made into corresponding prefabricated "standard parts" according to the cylinder body material specifications of the cylinder, which can be configured on demand and has strong mobility.

[0107] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements and other changes made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0108] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0109] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A cylinder buffer valve, characterized in that: The oil cylinder buffer valve (8) comprises: A valve body (11) is provided with a plunger cavity opening toward a first end (111) of the valve body, 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 internally connected oil passage (20) is formed in the valve body (11) and extends inwardly from the first end valve body oil port (101) to a cavity peripheral wall of the plunger cavity; The throttling plunger (3) is a hollow plunger and can be axially slidably extended from the plunger cavity toward the first end (111) of the valve body. A throttling groove (33) is provided on the plunger peripheral wall of the throttling plunger (3). The throttling plunger (3) includes a plunger contact end (31) extending out of the first end (111) of the valve body. The hollow plunger cavity of the throttling plunger (3) is a hollow plunger oil passage (32) and one end is closed by the plunger contact end (31), and the other end is connected to the second end valve body oil port (102); A pressure compensator (1) for stabilizing the pressure difference before and after the throttling groove (33); The throttling groove (33) is formed as a throttling port that connects the first internal connecting oil passage (20) and the hollow plunger oil passage (32).

2. The cylinder buffer valve according to claim 1, characterized in that: The pressure compensator (1) is a differential pressure reducing valve arranged in the valve body (11), and the control chambers at both ends of the differential pressure reducing valve are respectively connected to the front and rear oil ports of the throttling groove (33).

3. The cylinder buffer valve according to claim 1, characterized in that: The valve body (11) is also provided with a second internally connected oil passage (40) extending inwardly from the first end valve body oil port (101) to the through end of the hollow plunger oil passage (32); a one-way valve (10) is provided in the second internally connected oil passage (40); the one-way valve (10) is configured to allow pressure oil to flow from the second end valve body oil port (102) to the first end valve body oil port (101) and to block the flow in the reverse direction.

4. The cylinder buffer valve according to claim 1, characterized in that: The throttle port is a thin-walled orifice. On the peripheral wall of the plunger, the throttle groove (33) penetrates radially and extends axially. The throttle groove (33) is configured such that the flow area of ​​the throttle port gradually decreases as the throttle plunger (3) slides axially inward toward the second end (112) of the valve body.

5. The oil cylinder buffer valve according to claim 4, characterized in that: The throttling groove (33) is a throttling groove with a rectangular cross section or a throttling groove with a triangular cross section.

6. The oil cylinder buffer valve according to claim 1, 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 extends toward and is fixed to the second end (112) of the valve body.

7. The oil cylinder buffer valve according to claim 6, characterized in that: The valve body (11) is also provided with a third internally connected oil passage (30) extending inwardly from the first end valve body oil port (101) to the cavity peripheral wall of the plunger cavity. The plunger peripheral wall of the throttling plunger (3) is also provided with a guide oil port (34) radially aligned with the throttling groove (33). When the return spring (14) is in the fully released energy position, the inner end of the third internally connected oil passage (30) is aligned and connected with the guide oil port (34).

8. The oil cylinder buffer valve according to claim 1, characterized in that: A plunger guide sleeve (12) close to the first end (111) of the valve body and a plunger guide rail (15) close to the second end (112) of the valve body are embedded in the plunger cavity.

9. The oil cylinder buffer valve according to claim 1, characterized in that: A circumferential sealing groove is provided on the outer peripheral wall of the valve body (11), and a circumferential sealing ring (19) is embedded in the circumferential sealing groove.

10. The cylinder cushion valve according to any one of claims 1 to 9, characterized in that: The oil cylinder buffer valve (8) comprises: The check valve (2) is arranged at the second end (112) of the valve body (11) and is connected to the hollow plunger cavity of the throttling plunger (3).

11. A hydraulic cylinder, characterized in that: The hydraulic cylinder (7) includes a cylinder buffer valve (8) according to any one of claims 1 to 10, and the cylinder buffer valve (8) is piston-shaped and embedded in the rodless cylinder chamber of the hydraulic cylinder (7), and the throttling plunger (3) extends toward the cylinder piston (72) of the hydraulic cylinder (7).

12. The hydraulic cylinder according to claim 11, characterized in that: The hydraulic cylinder (7) comprises a fixedly installed rodless chamber end cover (74) and a detachably installed rod chamber end cover (75), and the cylinder buffer valve (8) can slide out of the cylinder barrel (71) of the cylinder from one side of the rod chamber end cover (75).

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