Hydraulic cylinder with built-in stroke valve and folding header for forage machine

Abstract

The present invention discloses a hydraulic cylinder with a built-in stroke valve, comprising a hydraulic cylinder body and a stroke valve, a piston assembly is provided on the cylinder inner cavity of the hydraulic cylinder body, and the piston assembly slides back and forth along the length direction of the cylinder inner cavity; the stroke valve comprises a valve body, an end cover and a valve core rod; the valve body is arranged at the bottom of the hydraulic cylinder body, a first oil chamber and a second oil chamber are provided in the valve body, and a sealing step is formed at the connection between the two, an oil inlet hole communicating with the first oil chamber and an oil outlet hole communicating with the second oil chamber are provided on the valve body, and a guide hole is also provided on the valve body; an accommodating cavity is provided on the end cover, and an elastic member is provided in the accommodating cavity; an oil through hole for connecting the cylinder inner cavity and the accommodating cavity is provided in the valve core rod, a sealing member is fixedly connected to the side wall of the valve core rod, the first end of the valve core rod extends into the accommodating cavity and is connected to the elastic member, and the elastic member is used to make the seal abut against the sealing step; the piston assembly moves toward the valve body to push the valve core rod to move and separate the seal from the sealing step.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, in particular to a hydraulic cylinder with a built-in stroke valve and a foldable cutting platform for a silage machine. Background Art

[0002] Currently, hydraulic engineering machinery or large hydraulic equipment requires multiple hydraulic cylinders to achieve logical sequence control, and many logical sequence controls are implemented using external stroke valves or sensors and electromagnetic reversing valves. However, in the field of agricultural machinery hydraulic systems, due to the limitations of installation space and the large number of movements, the cost of controlling the movement sequence of hydraulic cylinders is high and difficult to achieve.

[0003] Existing hydraulic cylinders with travel valves usually have the following defects:

[0004] 1. The conventional stroke valve is set outside the cylinder. The stroke valve is pushed by the extension or retraction of the cylinder to control the next level of action. The contact surface of the stroke valve push rod is in the external space and is provided with a block. It is easy to accidentally touch the push rod to open the stroke valve.

[0005] 2. The shortcoming of conventional built-in stroke valves is that the valve core push rod is located in the rodless chamber of the cylinder. The pressure will act on the valve core push rod. When the force is greater than the spring force, the push rod will be pushed to move, and the oil inlet and outlet of the stroke valve will be connected, causing the next level of stroke valve control to malfunction. As a result, the internal spring preload force of the conventional built-in stroke valve is large and the diameter of the stroke valve push rod is small. Summary of the Invention

[0006] The present invention provides a hydraulic cylinder with a built-in stroke valve to solve the technical problem of how to prevent the stroke valve from having control errors.

[0007] The cam is secured to the upper and lower ends of the hydraulic cylinder to allow the cam to flow freely in the hydraulic cylinder, and the cam is secured on the lower end of the hydraulic cylinder to the upper and lower ends of the hydraulic cylinder to the lower ends of the hydraulic cylinder. The guide hole of the cylinder body cavity; the end cover is provided with an accommodating cavity, and an elastic member is arranged in the accommodating cavity; the valve core rod is provided with an oil hole for connecting the cylinder body cavity and the accommodating cavity, and a sealing member is fixedly connected to the side wall of the valve core rod, the first end of the valve core rod extends into the accommodating cavity and is connected to the elastic member, the outer wall of the first end of the valve core rod is fitted and sealed with the inner wall of the accommodating cavity, and the elastic member is used to push the valve core rod to move toward the cylinder body cavity so that the seal abuts against the sealing step; the second end of the valve core rod passes through the guide hole and extends into the oil cylinder cavity, the outer wall of the second end of the valve core rod is fitted and sealed with the inner wall of the guide hole, and the piston assembly moves toward the valve body to push the valve core rod to move and separate the seal from the sealing step.

[0008] Furthermore, a spring cavity is formed on the valve core rod, the elastic member extends into the spring cavity and abuts against the bottom of the spring cavity, and the elastic member fits against the inner wall of the spring cavity.

[0009] Furthermore, a limiting rod is provided in the accommodating cavity, and the elastic member is sleeved on the limiting rod to prevent the elastic member from circumferential movement.

[0010] Furthermore, the piston assembly includes a piston head and a piston rod fixedly connected to the piston head, the piston head is slidably connected in the inner cavity of the cylinder body and divides the inner cavity of the cylinder body into a rodless cavity and a rod cavity, the rodless cavity of the cylinder is connected to the oil hole, the piston rod is located in the rod cavity of the cylinder and one end extends out of the inner cavity of the cylinder body, and the hydraulic cylinder body is also provided with a rodless cavity oil inlet channel connected to the rodless cavity of the cylinder and a rod cavity oil inlet channel connected to the rod cavity of the cylinder.

[0011] Furthermore, an oil groove is provided on the valve core rod, which is connected to the oil hole and is located in the cylinder body cavity. The oil groove is used to form an oil gap when the piston head abuts the valve core rod to discharge the oil in the accommodating cavity.

[0012] Furthermore, the valve body is connected to the hydraulic cylinder body through threads, and a first sealing ring is provided between the valve body and the hydraulic cylinder body.

[0013] Furthermore, the end cover is connected to the valve body via threads, and a second sealing ring is provided between the end cover and the valve body.

[0014] Furthermore, a third sealing ring is provided between the outer wall of the first end of the valve core rod and the inner wall of the accommodating cavity; and a fourth sealing ring is provided between the second end of the valve core rod and the inner wall of the oil hole.

[0015] Furthermore, the sealing member is in a cone shape, the radius of the sealing member gradually decreases from the first oil chamber to the second oil chamber, and the minimum radius of the sealing member is smaller than the radius of the first oil chamber.

[0016] Furthermore, the diameter of the first end surface of the valve core rod is the same as the diameter of the second end surface of the valve core rod.

[0017] According to another aspect of the present invention, a foldable harvesting platform for a forage machine is provided, comprising the hydraulic cylinder with the built-in stroke valve as described above.

[0018] The present invention has the following beneficial effects:

[0019] In the hydraulic cylinder with a built-in stroke valve of the present invention, the stroke valve is detachably mounted at the bottom of the hydraulic cylinder body and communicates with the cylinder inner cavity, so that the valve core rod of the stroke valve is located inside the hydraulic cylinder, thereby preventing external factors from interfering with the valve core rod and affecting the control structure of the valve core rod. In addition, because the valve core rod is provided with an oil hole to connect the cylinder inner cavity with the accommodating chamber, the hydraulic pressure in the accommodating chamber and the cylinder inner cavity is kept consistent, thereby eliminating the influence of the pressure exerted by the oil in the hydraulic cylinder body on the valve core rod, so that the valve core rod can normally control the valve. When the cam is in the closed position, the piston in the oil pumping station is in the closed position, and the oil in the oil pumping station is in the open position, so that the oil in the oil pumping station is in the open position, and the oil in the oil pumping station is in the open position. When the cam is in the closed position, the oil in the oil chamber is in the closed position, and the oil in the oil chamber is in the open position, so that the oil in the oil chamber is in the open position and the oil pressure in the oil chamber is in the open position. In summary, the valve stem of the stroke valve is placed inside the hydraulic cylinder to prevent external factors from interfering with the stem. At the same time, an oil hole is provided on the stem to maintain consistent oil pressure at both ends of the stem, thus preventing the oil pressure from affecting the stem's operation and preventing the oil pressure at one end of the cylinder cavity from being greater than the oil pressure at the other end of the accommodating cavity, which could cause the stem to malfunction. By placing the stroke valve inside the hydraulic cylinder and providing an oil hole on the stem to maintain consistent oil pressure at both ends of the stem, the technical problem of preventing control errors in the stroke valve is solved.

[0020] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 1 is a schematic structural diagram of a hydraulic cylinder body according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a structural diagram of a preferred embodiment of the present invention in which the travel valve is in a closed state;

[0024] Figure 3 It is a structural schematic diagram of a preferred embodiment of the present invention when the travel valve is in an open state.

[0025] Legend:

[0026] 100, hydraulic cylinder body; 101, oil cylinder rodless chamber; 102, oil inlet passage for the rodless chamber; 103, oil cylinder rod chamber; 104, oil inlet passage for the rod chamber;

[0027] 200, piston head; 201, piston rod;

[0028] 300, valve body; 301, first oil chamber; 302, second oil chamber; 303, sealing step; 304, oil inlet hole; 305, oil outlet hole; 306, guide hole;

[0029] 400, end cover; 401, accommodating cavity; 402, limiting rod;

[0030] 500, valve core rod; 501, seal; 502, oil hole; 503, oil groove; 504, spring chamber;

[0031] 600, first sealing ring; 601, second sealing ring; 602, third sealing ring; 603, fourth sealing ring;

[0032] 700. Elastic parts. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0034] like Figures 1 to 3As shown, a hydraulic cylinder with a built-in stroke valve in this embodiment includes a hydraulic cylinder body 100 and a stroke valve, the hydraulic cylinder body 100 includes a cylinder inner cavity, a piston assembly is provided on the cylinder inner cavity, and the piston assembly slides back and forth along the length direction of the cylinder inner cavity; the stroke valve includes a valve body 300, an end cover 400 fixed to the bottom of the valve body 300 and a valve core rod 500 provided in the valve body 300; the valve body 300 is detachably connected to the bottom of the hydraulic cylinder body 100, a first oil chamber 301 and a second oil chamber 302 that are connected to each other are defined in the valve body 300, a sealing step 303 is formed at the connection between the first oil chamber 301 and the second oil chamber 302, an oil inlet hole 304 that is connected to the first oil chamber 301 and an oil outlet hole 305 that is connected to the second oil chamber 302 are defined on the valve body 300, and a guide hole 306 for connecting the first oil chamber 301 and the cylinder inner cavity is further defined on the valve body 300; An accommodating chamber 401 is provided, and an elastic member 700 is provided in the accommodating chamber 401; an oil hole 502 for connecting the inner cavity of the cylinder body and the accommodating chamber 401 is provided in the valve core rod 500, and a sealing member 501 is fixedly connected to the side wall of the valve core rod 500, and the first end of the valve core rod 500 extends into the accommodating chamber 401 and is connected to the elastic member 700, and the outer wall of the first end of the valve core rod 500 is sealed with the inner wall of the accommodating chamber 401, and the elastic member 700 is used to push the valve core rod 500 to move toward the inner cavity of the cylinder body so that the seal 501 abuts against the sealing step 303; the second end of the valve core rod 500 passes through the guide hole 306 and extends into the inner cavity of the cylinder, and the outer wall of the second end of the valve core rod 500 fits and seals with the inner wall of the guide hole 306, and the piston assembly moves toward the valve body 300 to push the valve core rod 500 to move and separate the seal 501 from the sealing step 303.

[0035] In this embodiment, the stroke valve includes a valve body 300, an end cover 400 and a valve core rod 500, wherein the valve body 300 is detachably fixed to the bottom of the hydraulic cylinder in the form of a threaded connection, and the end cover 400 is also detachably fixed to the bottom end of the valve body 300 in the form of a threaded connection. Such an arrangement facilitates subsequent maintenance and adjustment of the stroke valve and the hydraulic cylinder body 100, and at the same time, the valve core rod 500 is slidably connected between the valve body 300 and the end cover 400. Specifically, the guide hole 306, the valve core rod 500 and the accommodating chamber 401 are all coaxially arranged, and the outer wall of the first end of the valve core rod 500 is fitted and sealed with the inner wall of the accommodating chamber 401, and the outer wall of the second end of the valve core rod 500 is fitted and sealed with the inner wall of the guide hole 306. The oil hole 502 opened on the valve core rod 500 connects the cylinder body cavity and the accommodating chamber 401 so that the oil pressure at both ends of the valve core rod 500 is always consistent. A first oil chamber 301 and a second oil chamber 302 are coaxially arranged inside the valve body 300, wherein the radius of the first oil chamber 301 is smaller than the radius of the second oil chamber 302, and a sealing step 303 is formed at the connection between the two. When the sealing member 501 abuts against the sealing step 303, the first oil chamber 301 and the second oil chamber 302 are separated, so that the valve is closed. When the sealing member 501 separates from the sealing step 303, the first oil chamber 301 and the second oil chamber 302 are connected, so that the valve is opened.

[0036] In a specific implementation, in the hydraulic cylinder with a built-in stroke valve of the present invention, the stroke valve is detachably mounted at the bottom of the hydraulic cylinder body 100 and communicates with the inner cavity of the cylinder body, so that the valve core rod 500 of the stroke valve is located inside the hydraulic oil cylinder, thereby preventing external factors from interfering with the valve core rod 500 and affecting the control structure of the valve core rod 500. In addition, because the valve core rod 500 is provided with an oil hole 502 to connect the inner cavity of the cylinder body with the accommodating chamber 401, the hydraulic pressure in the accommodating chamber 401 and the inner cavity of the cylinder body are consistent, thereby eliminating the influence of the pressure exerted on the valve core rod 500 by the oil in the hydraulic cylinder body 100, so that the valve core rod 500 can normally control the valve.

[0037] Specifically, when the oil enters the inner cavity of the cylinder body and pushes the piston assembly to move in the direction away from the stroke valve, the piston extends out of the hydraulic cylinder body 100. At this time, the oil enters the accommodating chamber 401 through the oil hole 502, so that the hydraulic pressure of the inner cavity part of the cylinder body separated by the piston assembly and close to the stroke valve is consistent with the hydraulic pressure of the accommodating chamber 401, that is, the oil pressure at both ends of the valve core rod 500 is consistent. At this time, under the action of the elastic member 700, the valve core rod 500 makes the seal 501 abut against the sealing step 303. At this time, the first oil chamber 301 and the second oil chamber 302 are separated by the seal 501, so that the valve is closed, and the oil input in the oil inlet hole 304 cannot enter the second oil chamber 302 and is discharged from the oil outlet hole 305.

[0038] When the piston assembly moves to the end away from the stroke valve, oil is continuously input into the hydraulic cylinder. Due to the oil hole 502, the accommodating chamber 401 and the inner cavity of the cylinder are always in a connected state, so that the oil pressure at both ends of the valve core rod 500 is the same. Under the action of the elastic member 700, the position of the valve core rod 500 remains unchanged, that is, the sealing member 501 abuts against the sealing step 303. At this time, the first oil chamber 301 and the second oil chamber 302 are separated by the sealing member 501, so that the valve is closed, and the oil input into the oil inlet hole 304 cannot enter the second oil chamber 302 and is discharged from the oil outlet hole 305.

[0039] When the piston assembly moves toward the valve core rod 500 and does not contact the valve core rod 500, due to the oil hole 502, the accommodating chamber 401 and the inner cavity of the cylinder body are always in a connected state, so that the oil pressure at both ends of the valve core rod 500 is the same. Under the action of the elastic member 700, the position of the valve core rod 500 remains unchanged, that is, the sealing member 501 abuts against the sealing step 303. At this time, the first oil chamber 301 and the second oil chamber 302 are separated by the sealing member 501, so that the valve is closed, and the oil input in the oil inlet hole 304 cannot enter the second oil chamber 302 and be discharged from the oil outlet hole 305.

[0040] When the piston assembly moves toward the valve core rod 500 and contacts the valve core rod 500, the valve core rod 500 moves under the push of the piston assembly and overcomes the elastic force of the elastic member 700, so that the sealing member 501 is separated from the sealing step 303. At this time, the first oil cylinder and the second oil chamber 302 are connected, the valve is opened, and the oil input into the oil inlet hole 304 enters the second oil chamber 302 and is discharged from the oil outlet hole 305.

[0041] In summary, the valve core rod 500 of the stroke valve is disposed inside the hydraulic cylinder to prevent external factors from interfering with the valve core rod 500. At the same time, an oil hole 502 is provided in the valve core rod 500 to maintain consistent oil pressure at both ends of the valve core rod 500, thereby preventing the oil pressure from affecting the operation of the valve core rod 500 and preventing the oil pressure at one end of the cylinder body from being greater than the oil pressure at one end of the accommodating chamber 401, thereby causing the valve core rod 500 to erroneously move. By disposing the stroke valve within the hydraulic cylinder body 100 and providing the oil hole 502 in the valve core rod 500 to maintain consistent oil pressure at both ends of the valve core rod 500, the technical problem of preventing control errors of the stroke valve is solved.

[0042] Furthermore, a spring cavity 504 is defined on the valve core rod 500 , the elastic member 700 extends into the spring cavity 504 and abuts against the bottom of the spring cavity 504 , and the elastic member 700 fits against the inner wall of the spring cavity 504 .

[0043] In this embodiment, the elastic member 700 is a compression spring. The spring cavity 504 and the oil hole 502 are coaxially arranged and interconnected. One end of the elastic member 700 abuts the bottom of the accommodating cavity 401, and the other end of the elastic member 700 extends into the spring cavity 504 and abuts the bottom of the spring cavity 504. To ensure that the elastic member 700 does not deviate during operation, the elastic member 700 is in close contact with the inner wall of the spring cavity 504. To ensure that the valve stem 500 always abuts the sealing member 501 against the sealing step 303 when not affected by the piston assembly, the elastic member 700 must have a certain preload, so that the elastic member 700 is always in a compressed state.

[0044] Furthermore, a limiting rod 402 is provided within the accommodating cavity 401, and the elastic member 700 is sleeved on the limiting rod 402 to prevent circumferential movement of the elastic member 700. In this embodiment, the limiting rod 402 is fixed to the bottom of the accommodating cavity 401, and the limiting rod 402 and the accommodating cavity 401 are arranged coaxially. The elastic member 700 is sleeved on the limiting rod 402 to prevent the elastic member 700 from shifting during compression.

[0045] Furthermore, the piston assembly includes a piston head 200 and a piston rod 201 fixedly connected to the piston head 200, the piston head 200 is slidably connected in the cylinder body cavity and divides the cylinder body cavity into a cylinder rodless cavity 101 and a cylinder rod cavity 103, the cylinder rodless cavity 101 is connected to the oil hole 502, the piston rod 201 is located in the cylinder rod cavity 103 and one end extends out of the cylinder body cavity, and the hydraulic cylinder body 100 is also provided with a rodless cavity oil inlet channel 102 connected to the cylinder rodless cavity 101 and a rod cavity oil inlet channel 104 connected to the cylinder rod cavity 103.

[0046] In this embodiment, the piston assembly includes a piston head 200 and a piston rod 201, wherein the piston head 200 is slidably connected in the inner cavity of the cylinder body, and the side wall of the piston head 200 is in contact with the cavity wall of the inner cavity of the cylinder body, and the inner cavity of the cylinder body is divided into two parts. The part without the piston rod 201 is the oil cylinder rodless cavity 101, and the part with the piston rod 201 is the oil cylinder rod cavity 103. The oil cylinder rodless cavity 101 is connected with the oil hole 502. A rodless cavity oil inlet channel 102 connected with the oil cylinder rodless cavity 101 is provided on the hydraulic cylinder body 100. When the piston needs to be moved in the direction away from the stroke valve, oil is injected into the rodless cavity oil inlet channel 102, and the piston is pushed to move by the pressure of the oil; a rod cavity oil inlet channel 104 connected with the oil cylinder rod cavity 103 is also provided on the hydraulic cylinder. When the piston needs to be moved in the direction of the stroke valve, oil is injected into the rod cavity oil inlet channel 104, and the piston is pushed to move by the pressure of the oil.

[0047] Furthermore, an oil groove 503 is provided on the valve core rod 500, and the oil groove 503 is connected to the oil hole 502 and is located in the inner cavity of the cylinder body. The oil groove 503 is used to form an oil gap when the piston head 200 abuts against the valve core rod 500 to discharge the oil in the accommodating chamber 401.

[0048] In this embodiment, an oil groove 503 is defined in the valve stem 500. This groove 503 ensures that when the piston retracts and abuts the valve stem 500, the oil in the accommodating chamber 401 can be discharged through the oil hole 502 and enter the rodless chamber of the oil chamber through the oil groove 503. The provision of the oil groove 503 ensures that the accommodating chamber 401 and the rodless chamber 101 of the oil cylinder are always connected, thereby effectively preventing the trip valve from erroneously opening when pressure is present in the rodless chamber 101 of the oil cylinder.

[0049] Furthermore, the valve body 300 is connected to the hydraulic cylinder body 100 via threads, and a first sealing ring 600 is provided between the valve body 300 and the hydraulic cylinder body 100 .

[0050] In this embodiment, the valve body 300 is threadedly connected to the bottom of the hydraulic cylinder body 100. A first sealing ring 600 is disposed between the valve body 300 and the hydraulic cylinder body 100 to enhance the sealing between the two bodies and prevent oil leakage through the gap between the valve body 300 and the hydraulic cylinder body 100. Specifically, a first annular groove is formed in the connection portion between the valve body 300 and the hydraulic cylinder body 100, and the first sealing ring 600 is embedded in the first annular groove. The valve body 300 and the hydraulic cylinder body 100 are then threadedly connected.

[0051] Furthermore, the end cover 400 is connected to the valve body 300 via threads, and a second sealing ring 601 is provided between the end cover 400 and the valve body 300 .

[0052] In this embodiment, the end cap 400 is threadedly connected to the valve body 300, facilitating subsequent removal of the end cap 400 for maintenance and adjustment of internal components of the valve body 300. To ensure a tight seal between the valve body 300 and the hydraulic cylinder 100, a second sealing ring 601 is provided at the connection between the end cap 400 and the valve body 300 to prevent leakage of oil in the second oil chamber 302 through the gap between the end cap 400 and the valve body 300. Specifically, a second annular groove is defined at the connection between the end cap 400 and the valve body 300, and the second sealing ring 601 is embedded in the second annular groove. The end cap 400 is then threadedly connected to the valve body 300.

[0053] Furthermore, a third sealing ring 602 is provided between the outer wall of the first end of the valve core rod 500 and the inner wall of the accommodating chamber 401 ; a fourth sealing ring 603 is provided between the second end of the valve core rod 500 and the inner wall of the oil hole 502 .

[0054] In this embodiment, the third sealing ring 602 is provided to ensure the sealing between the accommodating chamber 401 and the valve core rod 500, so as to separate the accommodating chamber 401 from the second oil chamber 302, so that the oil in the accommodating chamber 401 cannot flow into the second oil chamber 302, so as to ensure that the oil in the cylinder body cavity will not leak from the oil outlet hole 305; the fourth sealing ring 603 is provided to ensure the sealing between the guide hole 306 and the valve core rod 500, so as to prevent the oil in the cylinder body cavity from flowing into the first oil chamber 301 through the guide hole 306, thereby causing leakage of the cylinder body oil chamber.

[0055] Furthermore, the sealing member 501 is in a cone shape, and the radius of the sealing member 501 gradually decreases from the first oil chamber 301 to the second oil chamber 302 , and the minimum radius of the sealing member 501 is smaller than the radius of the first oil chamber 301 .

[0056] In this embodiment, the seal 501 is conical in shape, and its radius gradually decreases from the first oil chamber 301 toward the second oil chamber 302. This allows the seal 501 to partially embed within the first oil chamber 301 during sealing. The inclined surface of the seal 501 provides a guide during embedding, allowing the seal 501 to smoothly embed within the first oil chamber 301 and abut against the inner wall of the first oil chamber 301.

[0057] Furthermore, the diameter of the first end surface of the valve core rod 500 is the same as the diameter of the second end surface of the valve core rod 500 .

[0058] In this embodiment, the diameters of the two ends of the valve core rod 500 are the same, so that the pressure areas at both ends of the valve core rod 500 are the same, thereby ensuring that the oil pressure at both ends of the valve core rod 500 is the same, thereby reducing the impact of the oil pressure on the operation of the valve core rod 500.

[0059] According to another aspect of the present invention, a foldable harvesting platform for a forager is provided, comprising the hydraulic cylinder with a built-in stroke valve as described above. The foldable harvesting platform for a forager has all the advantages of the hydraulic cylinder with a built-in stroke valve as described above.

[0060] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A hydraulic cylinder with a built-in stroke valve, characterized in that: include: A hydraulic cylinder (100), comprising an inner cylinder cavity, a piston assembly for sliding back and forth in the inner cylinder cavity along a length direction of the inner cylinder cavity is provided at a first end of the hydraulic cylinder (100), and the piston assembly slides back and forth along the length direction of the inner cylinder cavity; A travel valve, comprising a valve body (300) whose first end is detachably connected to the second end of a hydraulic cylinder body (100), an end cover (400) fixed to the second end of the valve body (300), and a valve core rod (500) disposed in the valve body (300); The valve body (300) is provided with a first oil chamber (301) and a second oil chamber (302) that are in communication with each other. A sealing step (303) is formed at the connection between the first oil chamber (301) and the second oil chamber (302). The valve body (300) is provided with an oil inlet hole (304) in communication with the first oil chamber (301) and an oil outlet hole (305) in communication with the second oil chamber (302). The valve body (300) is also provided with a guide hole (306) for connecting the first oil chamber (301) and the inner cavity of the cylinder body. The end cover (400) is provided with a receiving cavity (401), and an elastic member (700) is provided in the receiving cavity (401); An oil hole (502) for connecting the inner cavity of the cylinder body and the accommodating cavity (401) is provided in the valve core rod (500), a sealing member (501) is fixedly connected to the side wall of the valve core rod (500), the first end of the valve core rod (500) extends into the accommodating cavity (401) and is connected to the elastic member (700), the outer wall of the first end of the valve core rod (500) is in close contact with the inner wall of the accommodating cavity (401), and the elastic member (700) is used to push the valve core rod (500) toward the inner cavity of the cylinder body so that the sealing member (501) abuts against the sealing step (303); The second end of the valve core rod (500) passes through the guide hole (306) and extends into the inner cavity of the cylinder body. The outer wall of the second end of the valve core rod (500) is sealed against the inner wall of the guide hole (306). The piston assembly moves toward the valve body (300) to push the valve core rod (500) to move and separate the sealing member (501) from the sealing step (303).

2. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: A spring cavity (504) is provided on the valve core rod (500), the elastic member (700) extends into the spring cavity (504) and abuts against the bottom of the spring cavity (504), and the elastic member (700) fits against the inner wall of the spring cavity (504).

3. The hydraulic cylinder with a built-in stroke valve according to claim 2, characterized in that: A limiting rod (402) is provided in the accommodating cavity (401), and the elastic member (700) is sleeved on the limiting rod (402) to prevent the elastic member (700) from circumferential movement.

4. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: The piston assembly includes a piston head (200) and a piston rod (201) fixedly connected to the piston head (200); the piston head (200) is slidably connected to the inner cavity of the cylinder body and divides the inner cavity of the cylinder body into a rodless cylinder cavity (101) and a rod cylinder cavity (103); the rodless cylinder cavity (101) is connected to the oil hole (502); the piston rod (201) is located in the rod cylinder cavity (103) and one end extends out of the inner cavity of the cylinder body; the hydraulic cylinder body (100) is also provided with a rodless cavity oil inlet channel (102) connected to the rodless cylinder cavity (101) and a rod cavity oil inlet channel (104) connected to the rod cylinder cavity (103).

5. The hydraulic cylinder with a built-in stroke valve according to claim 4, characterized in that: An oil groove (503) is provided on the valve core rod (500), the oil groove (503) is connected to the oil hole (502) and is located in the inner cavity of the cylinder body, and the oil groove (503) is used to form an oil gap when the piston head (200) abuts against the valve core rod (500) to discharge the oil in the accommodating cavity (401).

6. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: The valve body (300) is connected to the hydraulic cylinder body (100) via threads, and a first sealing ring (600) is provided between the valve body (300) and the hydraulic cylinder body (100).

7. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: The end cover (400) is connected to the valve body (300) via threads, and a second sealing ring (601) is provided between the end cover (400) and the valve body (300).

8. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: A third sealing ring (602) is provided between the outer wall of the first end of the valve core rod (500) and the inner wall of the accommodating cavity (401); a fourth sealing ring (603) is provided between the second end of the valve core rod (500) and the inner wall of the oil hole (502).

9. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: The sealing member (501) is in a cone shape, the radius of the sealing member (501) gradually decreases from the first oil chamber (301) to the second oil chamber (302), and the minimum radius of the sealing member (501) is smaller than the radius of the first oil chamber (301).

10. The hydraulic cylinder with a built-in stroke valve according to claim 1, characterized in that: The diameter of the first end surface of the valve core rod (500) is the same as the diameter of the second end surface of the valve core rod (500).

11. A foldable header for a silage machine, characterized in that: A hydraulic cylinder comprising a built-in stroke valve as claimed in any one of claims 1 to 10.

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