Hydraulic oil cylinder assembly

Abstract

The invention relates to the technical field of hydraulic oil cylinders, in particular to a hydraulic oil cylinder assembly which comprises a cylinder cover, a cylinder barrel, a piston, a cushion collar, a push rod, a cylinder head, a dustproof ring, a guide rod, an impeller and a shifting block. The upper end and the lower end of the push rod penetrate through the piston and the cylinder head respectively, the dustproof ring is arranged between the cylinder head and the push rod, the guide rod is connected to the lower portion of the cylinder cover and inserted into the push rod, and the impeller is installed at the upper end of the first oil hole. The hydraulic oil at the position of the first oil hole drives the impeller to rotate and is pressurized by the impeller to be discharged to the second oil hole through the guide rod at the same time, and the oil amount discharged to the second oil hole is in positive correlation with the oil inlet speed of the first oil hole. The purpose of automatically adjusting the buffering force of the hydraulic oil cylinder under different hydraulic pressures is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic cylinders, in particular to a hydraulic cylinder assembly. Background Art

[0002] Hydraulic cylinders are hydraulic actuators that convert hydraulic energy into mechanical energy. With the help of hydraulic power, they can perform linear motion or swing, and are widely used in mechanical processing, lifting, automobiles and other fields. According to the movement of the piston inside the hydraulic cylinder, it can be divided into balanced type and push-pull type. The balanced type can make the piston stop at a fixed point, while the push-pull type makes the piston do linear reciprocating motion inside the cylinder. In comparison, the push-pull type is more commonly used in the field of mechanical processing due to its advantages of simple structure and high reliability. For example, it is used in punching machines to achieve the punching of workpieces through the reciprocating movement of the hydraulic cylinder itself.

[0003] The piston of the push-pull hydraulic cylinder on the punch press is driven by high hydraulic pressure and has a very high speed during the movement. It is precisely with the high kinetic energy brought by the high speed that the workpiece can be punched. However, although the high-speed moving piston can punch the workpiece, because the push-pull cylinder does not have the function of balancing the cylinder to stop the piston at a fixed point, it will inevitably cause impact on the cylinder head and cylinder cover at both ends of the cylinder barrel, making the hydraulic cylinder prone to strength problems, resulting in reduced production efficiency. The prior art will install a buffer device at both ends of the cylinder barrel, and increase the pressure of the discharge chamber by reducing the flow of the hydraulic oil discharge port at the end of the punching process, so that the piston stops quickly. For example, in a low-delay start-up and anti-internal leakage buffer cylinder for a four-level or higher gantry with a publication number of CN107235451B, throttling is performed through the annular gap between the buffer cylinder and the piston, and a large back pressure is formed in the oil discharge chamber to achieve the purpose of buffering the piston.

[0004] The existing technology can realize the buffering function of the hydraulic cylinder through the annular gap, but this buffering method is inconvenient for adjusting the buffering force. When using a punch press for punching, it is necessary to adjust the hydraulic pressure of the hydraulic cylinder according to the parameters of the workpiece, such as thickness, material, etc., and accordingly, the buffering force also needs to be adjusted to avoid the following situations: when the hydraulic pressure increases, the buffering force is too small, resulting in the attenuation or even failure of the buffering effect; when the hydraulic pressure decreases, the buffering force is too large, which will make the punch press insufficiently punch the workpiece, and the adjustment of the buffering force in the existing technology is achieved by further adjusting the throttling amount of the oil discharge port valve. However, for micro-sized enterprises with only a small number of punch presses, this adjustment is quite inconvenient when using the same punch press to process multiple workpieces: when using a punch press to punch workpieces of different materials or different thicknesses, a hydraulic pressure that matches the various workpieces is required, and manually adjusting the flow of the oil discharge port is obviously a process of multiple debugging, which is time-consuming and labor-intensive, and reduces production efficiency.

[0005] For this purpose, a hydraulic cylinder assembly is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a hydraulic cylinder assembly, which solves the problem of inconvenient adjustment of the buffer force of the hydraulic cylinder, thereby affecting the production efficiency of the equipment. By discharging a corresponding amount of hydraulic oil from the oil inlet to the oil outlet according to the downward speed of the piston during the buffering process, the purpose of automatically adjusting the buffer force of the hydraulic cylinder under different hydraulic pressures is achieved.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A hydraulic cylinder assembly includes a cylinder cover, a cylinder barrel, a piston, a buffer sleeve, a push rod, a cylinder head, a dust ring, a guide rod, an impeller and a shift block. The cylinder cover and the cylinder head are respectively connected to the upper and lower ends of the cylinder barrel, and the cylinder cover and the cylinder head are respectively provided with a first oil hole and a second oil hole. The piston slides inside the cylinder barrel, the buffer sleeve is connected below the piston, the upper and lower ends of the push rod respectively pass through the piston and the cylinder head, the dust ring is arranged between the cylinder head and the push rod, the push rod is hollow inside, the hollow guide rod is connected to the bottom of the cylinder cover and inserted into the push rod, and the upper and lower ends of the guide rod are respectively connected to the first oil hole and the second oil hole, the impeller is installed at the upper end of the first oil hole, and the shift block is inserted into the lower part of the guide rod along the left and right direction.

[0009] When the push rod drives the buffer sleeve downward, the inside of the push rod contacts the shift block to block the internal channel of the guide rod. When the buffer sleeve enters the cylinder head, the shift block is pushed by the push rod to gradually open the internal channel of the guide rod. The hydraulic oil at the first oil hole drives the impeller to rotate and is pressurized by the impeller and discharged to the second oil hole through the guide rod, and the amount of oil discharged to the second oil hole is positively correlated with the oil inlet speed of the first oil hole.

[0010] The prior art only forms quantitative throttling by annular gaps of fixed shape, and it is obviously impossible to adjust the throttling amount to a suitable amount at one time by adjusting the throttling amount of the oil discharge valve. In addition, a real-time stamping simulation must be performed during the adjustment process. During the simulation process, there is a risk of operating errors, making the buffer force too small and the hydraulic pressure too large, thereby damaging the hydraulic cylinder. Therefore, this scheme considers eliminating such real-time simulation, and instead enables the hydraulic cylinder to have the function of adjusting the buffer force according to the hydraulic pressure at the beginning of production: at the beginning of buffering, that is, when the buffer sleeve enters the cylinder head, the hydraulic oil pressure below the piston inside the cylinder is relatively large, and the second oil hole is connected to the oil tank, and the internal pressure is relatively small, so the hydraulic oil in the first oil hole is discharged to the second oil hole through the guide rod, and the area of ​​the second oil hole is constant, and the oil output is limited. After the hydraulic oil in the first oil hole enters, the hydraulic oil below the piston will inevitably be more difficult to enter the cylinder head, that is, the buffer force will increase, and this increase changes with the change of the oil inlet amount of the first oil hole (that is, the downward speed of the piston).

[0011] Preferably, the push rod includes an upper rod, a transition rod and a lower rod, the outer contours of the upper rod, the transition rod and the lower rod are the same and coaxial, and the upper rod, the transition rod and the lower rod are respectively provided with a first hole segment, a second hole segment and a third hole segment, the central axis of the first hole segment is on the right side of the central axis of the guide rod, the second hole segment is a pair of right-angled trapezoids with the same shape, overlapping lower bases and right-angled edges relative to the central axis of the guide rod on the projection of the longitudinal plane passing through the central axis of the guide rod, the central axis of the third hole segment is on the left side of the central axis of the guide rod, a nozzle is provided on the left side of the shift block, and the shift block contacts the third hole segment, the second hole segment and the first hole segment in sequence.

[0012] Through the above scheme, the first hole segment, the second hole segment, and the third hole segment are connected to the first oil hole and the second oil hole, and the three are moved while pushing the shift block to the left or right to block or discharge the hydraulic oil inside the guide rod, so that when the oil cylinder enters the buffer state, the guide rod can discharge the internal hydraulic oil to the second oil hole, thereby realizing the change of the buffer force.

[0013] As a hydraulic cylinder used in a punch press, the requirement for the stroke is not precise, so the push rod can stop normally after the cylinder completes the stamping. That is to say, if no buffer device is added, increasing the length of the cylinder barrel so that the push rod has enough "braking distance" is also a feasible solution, but obviously the cylinder barrel is too long, which is not conducive to production and installation, and will also reduce the reciprocating efficiency of the cylinder; another solution is to make the push rod not subject to buffering force before buffering, and to give the push rod enough buffering force at one time during buffering, so there is no need to adjust the buffering force, because the circulation of hydraulic oil accompanies the entire process of cylinder movement. This solution cannot be directly achieved by throttling. A simpler way is to install a mechanical buffer structure similar to a spring above the cylinder head, but since it is a mechanical structure, it cannot avoid damage caused by mechanical collision. Therefore, the life of this method is limited, and impurities generated by the collision will affect the quality of the hydraulic oil. In the present solution, on the one hand, the hydraulic oil displacement from the first oil hole to the second oil hole is positively correlated with the downward speed of the piston when the hydraulic cylinder starts to buffer through the guide rod and the impeller, so that the buffering force is related to the downward speed of the piston; on the other hand, with the help of a series of measures, the pressure when the hydraulic oil inside the guide rod is discharged (i.e., the buffering process) is increased as much as possible, so that the buffering force of the cylinder does not change significantly before buffering, and will be greatly increased at the beginning of buffering, thereby allowing the piston to be effectively buffered without the hidden dangers caused by collision of the mechanical device.

[0014] Preferably, the nozzle is configured as a tapered hole with the large diameter end of the nozzle on top, so that the hydraulic oil inside the guide rod has a greater pressure when discharged to the second oil hole, so that the back pressure formed in the cylinder head can provide sufficient buffering force.

[0015] Preferably, the upper and lower end faces of the shift block are in the shape of long waist circles, and the diameter of the long waist circle of the shift block is equal to the diameter of the first hole segment and the second hole segment, thereby increasing the contact area between the shift block and the first hole segment, the second hole segment and the third hole segment, avoiding scratches caused by small-area contact, resulting in the risk of movement obstruction between the shift block and the first hole segment, the second hole segment and the third hole segment. The upper end of the lower rod is provided with an oil hole, which is configured as a tapered hole with a small diameter end connected to the third hole segment, and the small diameter value of the oil hole is smaller than the thickness of the shift block, thereby preventing the shift block from being inserted into the oil hole to hinder the operation of the push rod and cause damage.

[0016] Preferably, the upper rod further comprises a guide hole and a buffer section, wherein the guide hole is arranged above the first hole section, and the guide hole is coaxial with the guide rod, so that the guide rod plays an auxiliary guiding role for the push rod, making the operation of the push rod more stable. The buffer section is arranged above the upper rod, and the interior of the guide hole and the lower end of the guide rod are respectively installed with a first sealing ring and a second sealing ring, wherein the first sealing ring prevents the communication between the upper cavity and the lower cavity, so that the downward pressure of the hydraulic cylinder will not be affected, and the second sealing ring fixes the bottom surface of the hydraulic oil in the guide rod, thereby avoiding the problem of excessive oil filling in the guide rod to affect the reciprocating efficiency of the piston, and the hydraulic oil between the first sealing ring and the second sealing ring can be discharged to the second oil hole during buffering, further increasing the buffering force during buffering, and the lower end of the third hole section is provided with an airway, so that the space below the second sealing ring is connected to the outside, thereby avoiding interference with the movement of the push rod.

[0017] In the prior art, the annular gap between the buffer column and the piston has various shapes, and the buffering effects of the annular gaps of various shapes are different. The consideration of the annular gap in this solution mainly focuses on the circumference of the buffer section and the buffer sleeve.

[0018] Preferably, the outer contours of the buffer section and the buffer sleeve are both set to be parabolas fitted by multiple oblique lines. The parabola has the best buffering effect, but is inconvenient to process, so a multi-inclined surface fitting method is adopted. The lower end surface of the buffer section and the upper end surface of the buffer sleeve are both inclined surfaces. The inclined surfaces can guide the hydraulic oil discharged from the first oil hole or the second oil hole to the periphery of the buffer section and the buffer sleeve at the initial stage when the buffer section and the buffer sleeve leave the cylinder cover and the cylinder head, so as to reduce the hydraulic loss caused by the hydraulic oil hitting the buffer section and the buffer sleeve.

[0019] Preferably, a first groove is provided at the connection between the buffer section and the upper rod, a first protrusion matching the first groove is provided below the cylinder cover, a second groove is provided on the buffer sleeve, and a second protrusion matching the second groove is provided above the cylinder head.

[0020] Through the above solution, with the help of the clearing formed by the first groove and the second groove, the connection between the buffer section and the upper rod will be more stable, and the overall structural strength of the buffer sleeve will be higher, so that the use of the hydraulic cylinder is more secure. In addition, before the buffering ends, the first protrusion or the second protrusion will first extend into the first groove or the second groove, which has a further buffering effect.

[0021] Preferably, the impeller comprises a main body, blade teeth and blade surfaces, the main body is rotatably connected to the inside of the cylinder cover, a plurality of blade teeth are continuously distributed on the circumference of the main body, and the blade surfaces are arranged between the blade teeth.

[0022] Through the above scheme, in the front view, the impeller rotates counterclockwise with the oil inlet at the first oil hole, and the distance between the impeller and the cylinder head is gradually reduced, so that the pressure of the hydraulic oil driven by the impeller rotation will continue to increase, thereby producing the following two states: 1. The pressure of the hydraulic oil driven by the impeller rotation will increase, and the rotation will be resisted. When the guide rod is closed inside, the hydraulic oil driven by the impeller cannot be discharged to the guide rod, so the resistance to rotation will be further increased. When the blade surface is facing downward, the impeller will only be subject to weak hydraulic power, so it is difficult for the impeller to continue to rotate, that is, the blade surface is kept facing downward, so that the first oil hole can normally enter the oil; 2. When the guide rod is open, since the pressure at the first oil hole is greater than that at the second oil hole, the hydraulic oil at the first oil hole will spontaneously flow to the inside of the guide rod, and at this time, the tooth surface will continue to rotate driven by the hydraulic oil flowing upward, and as the hydraulic oil drives the blade teeth, the impeller speed is positively correlated with the piston descending speed.

[0023] Preferably, the blade teeth are arranged in an arc shape, and the bending direction of the blade teeth is the same as the rotation direction of the main body. The arc-shaped design is conducive to the blade teeth carrying more hydraulic oil for pressurization and then discharging it into the guide rod, and the pressurization effect of the impeller can be placed in a suitable range by designing the curvature of the blade teeth.

[0024] Preferably, a fixing sleeve is provided at the upper end of the guide rod, and the fixing sleeve is connected to the bottom of the cylinder head to strengthen the fixation of the guide rod. The fixing sleeve is set as a truncated cone structure with a small bottom surface at the bottom, which can guide the hydraulic oil at the first oil hole to the buffer section to avoid hydraulic loss of the hydraulic oil. The upper part of the dust ring is set as a truncated cone structure with a small bottom surface at the top, which can facilitate the insertion of the dust ring into the cylinder head and guide the hydraulic oil at the second oil hole to the buffer sleeve to avoid hydraulic loss of the hydraulic oil.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention makes the shift block contact with the inner wall of the push rod, opens the internal channel of the guide rod during the buffering process, and discharges the hydraulic oil at the first oil hole to the second oil hole to increase the downward resistance of the piston (i.e., the buffering force), and through the impeller, the discharge amount of the hydraulic oil is associated with the downward speed of the piston, thereby making the buffering force associated with the kinetic energy of the piston during buffering, so that the hydraulic cylinder can achieve self-adjustment of the buffering force, avoiding the influence of manual adjustment on production efficiency.

[0027] 2. The present invention designs the impeller so that it can pressurize the hydraulic oil at the first oil hole and discharge it to the second oil hole to increase the buffering force during buffering, without affecting the oil inlet of the first oil hole outside the buffering process. In addition, during the upward movement of the piston, with the help of the small gap between the impeller and the cylinder head, the liquid pressure in the cylinder head will act more on the bottom of the piston, thereby making the piston move upward quickly to ensure the working efficiency of the hydraulic cylinder.

[0028] 3. The present invention uses a fixing sleeve to guide the hydraulic oil at the first oil hole while strengthening the fixation of the guide rod, so that the guide rod can cooperate with the guide hole to provide more stable guidance for the push rod while cooperating with the shift block to discharge the hydraulic oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall isometric structure of the present invention;

[0030] Figure 2 For the present invention Figure 1 A schematic diagram of the structure of part B in the middle is enlarged;

[0031] Figure 3 It is a schematic diagram of the overall front view and full cross-section structure of the present invention;

[0032] Figure 4 For the present invention Figure 3 A schematic diagram of the enlarged structure of parts C, D, and E;

[0033] Figure 5 For the present invention Figure 1 A schematic diagram of the structure enlargement of part A;

[0034] Figure 6 This is a schematic diagram of the pre-buffering state of the present invention;

[0035] Figure 7 It is a schematic diagram of the buffer state of the present invention;

[0036] Figure 8 It is a schematic diagram of the buffering end state of the present invention.

[0037] In the figure: 1. cylinder head; 11. first oil hole; 12. first protrusion; 2. cylinder barrel; 3. piston; 4. buffer sleeve; 41. second groove; 5. push rod; 51. upper rod; 511. first hole section; 512. guide hole; 5121. first sealing ring; 513. buffer section; 5131. first groove; 52. transition rod; 521. second hole section; 53. lower rod; 531. third hole section; 532. oil hole; 533. air duct; 6. cylinder head; 61. second protrusion; 62. second oil hole; 7. dust ring; 8. guide rod; 81. second sealing ring; 82. fixing sleeve; 9. impeller; 91. main body; 92. blade teeth; 93. blade surface; 10. shift block; 101. nozzle. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] See also Figures 1 to 8 The present invention provides a hydraulic cylinder assembly, and the technical solution is as follows:

[0040] A hydraulic cylinder assembly includes a cylinder cover 1, a cylinder barrel 2, a piston 3, a buffer sleeve 4, a push rod 5, a cylinder head 6, a dust ring 7, a guide rod 8, an impeller 9 and a shift block 10. The cylinder cover 1 and the cylinder head 6 are welded to the upper and lower ends of the cylinder barrel 2, respectively, and the cylinder cover 1 and the cylinder head 6 are respectively provided with a first oil hole 11 and a second oil hole 62. The cylinder cover 1 and the cylinder head 6 are cast. During casting, the first oil hole 11, the second oil hole 62 and the hole position of the impeller 9 are cast together. The cylinder cover 1 is cast in parts. After the impeller 9 is installed on one side of the cylinder cover 1, the cylinder cover 1 is welded to the cylinder cover 1 on the other side. As another processing method, the cylinder cover 1 can also be cast as a whole. Before casting, a hole groove is reserved so that one side of the hole position of the impeller 9 can be connected to the outside world, and then the impeller 9 is installed along the hole groove, and finally the hole groove is welded and blocked. It should be noted that the sealing of the oil cylinder must be guaranteed, so the weld should be tight and the sealing test should be carried out after welding. The piston 3 slides inside the cylinder 2, the buffer sleeve 4 is connected to the bottom of the piston 3, the upper and lower ends of the push rod 5 pass through the piston 3 and the cylinder head 6 respectively, the dust ring 7 is arranged between the cylinder head 6 and the push rod 5, the push rod 5 is hollow inside, the hollow guide rod 8 is connected to the bottom of the cylinder head 1 and inserted into the push rod 5, and the upper and lower ends of the guide rod 8 are connected to the first oil hole 11 and the second oil hole 62 respectively, and the shift block 10 is inserted into the lower part of the guide rod 8 along the left and right direction.

[0041] While the push rod 5 drives the buffer sleeve 4 downward, the inside of the push rod 5 contacts the shift block 10 to block the internal channel of the guide rod 8. While the buffer sleeve 4 enters the cylinder head 6, the shift block 10 is pushed by the push rod 5 and gradually opens the internal channel of the guide rod 8. The hydraulic oil at the first oil hole 11 drives the impeller 9 to rotate and is pressurized by the impeller 9 and discharged to the second oil hole 62 through the guide rod 8. The amount of oil discharged to the second oil hole 62 is positively correlated with the oil inlet speed of the first oil hole 11, and the oil inlet speed of the first oil hole 11 is directly related to the downward speed of the piston 3. Therefore, the greater the liquid pressure on the piston 3, the faster its own downward speed, and the faster the oil inlet speed of the first oil hole 11, thereby increasing the amount of oil discharged to the second oil hole 62 to increase the buffering force of the cylinder.

[0042] As an embodiment of the present invention, refer to Figures 1 to 3The push rod 5 includes an upper rod 51, a transition rod 52 and a lower rod 53. The outer contours of the upper rod 51, the transition rod 52 and the lower rod 53 are the same and coaxial. The upper rod 51 includes a first hole section 511, a guide hole 512 and a buffer section 513. The guide hole 512 is arranged above the first hole section 511, and the guide hole 512 is coaxial with the guide rod 8, so that the guide rod 8 plays an auxiliary guiding role for the push rod 5, so that the operation of the push rod 5 is smoother. The buffer section 513 is arranged above the upper rod 51. A first sealing ring 5121 is installed inside the guide hole 512. The installation position of the first sealing ring 5121 is a groove inside the guide hole 512. Auxiliary tools are needed during installation. First, the back ring of the first sealing ring 5121 is pushed into the installation position of the first sealing ring 5121 from the lower end of the upper rod 51 using tools, and then one side of the first sealing ring 5121 is first extended from the lower end of the guide hole 512. Then, with the help of tools inserted from the top and bottom of the guide hole 512, the first sealing ring 5121 is fitted with its back ring. The lower end of the guide rod 8 is installed with a second sealing ring 81. The installation method is similar to that of the first sealing ring 5121. The second sealing ring 81 can be inserted into the groove at the bottom of the guide rod 8. In order to further improve the sealing performance, adhesive can be added during installation. The first sealing ring 5121 prevents the upper chamber from being connected to the lower chamber, so that the downward pressure of the hydraulic cylinder will not be affected. The second sealing ring 81 fixes the bottom surface of the hydraulic oil in the guide rod 8, thereby avoiding the problem of excessive oil filling in the guide rod 8, which affects the reciprocating efficiency of the piston 3. Moreover, the hydraulic oil between the first sealing ring 5121 and the second sealing ring 81 can be discharged to the second oil hole 62 during buffering. The oil discharge here has less resistance to the piston 3 before buffering, because the second oil hole 62 has smooth oil discharge before buffering, but the buffering force will be further increased during buffering. The lower end of the third hole section 531 is provided with an air channel 533, so that the space below the second sealing ring 81 is connected to the outside world, thereby avoiding interference with the movement of the push rod 5. The transition rod 52 and the lower rod 53 are respectively provided with a second hole section 521 and a third hole section 531. The central axis of the first hole section 511 is on the right side of the central axis of the guide rod 8. The second hole section 521 is a pair of right-angled trapezoids with the same shape, overlapping lower bases, and right-angled edges relative to the central axis of the guide rod 8 on the projection of the longitudinal plane passing through the central axis of the guide rod 8. The central axis of the third hole section 531 is on the left side of the central axis of the guide rod 8. The upper rod 51, the transition rod 52, and the lower rod 53 are welded into one. Before welding, the first hole section 511, the guide hole 512, the buffer section 513, the second hole section 521, the third hole section 531 and the airway 533 are first processed. The internal hole and groove structure is relatively complicated. Except for the buffer section 513, the other parts can be cast together when the upper rod 51, the transition rod 52, and the lower rod 53 are cast. The buffer section 513, as a part of the upper rod 51, can be obtained by later turning.The shift block 10 needs to slide left and right on the guide rod 8, so the installation should not be too tight. This looseness will not have a big impact on the cooperation between the shift block 10 and the guide rod 8, because the amount of oil flowing in the small gap is limited. The surface of the shift block 10 and the edges of the installation position of the shift block 10 on the guide rod 8 should be sprayed to improve the wear resistance. The shape of the upper and lower end faces of the shift block 10 is a long waist circle, and the diameter of the long waist circle of the shift block 10 is equal to the diameter of the first hole section 511 and the second hole section 521, thereby increasing the contact area between the shift block 10 and the first hole section 511, the second hole section 521, and the third hole section 531, avoiding scratches caused by small area contact, resulting in the risk of obstruction of movement between the shift block 10 and the first hole section 511, the second hole section 521, and the third hole section 531. The upper end of the lower rod 53 is provided with an oil hole 532, which is set as a tapered hole with a small diameter end connected to the third hole section 531. The opening of the oil hole 532 should be prior to the welding between the upper rod 51, the transition rod 52 and the lower rod 53, so as to avoid damage to the welding performance during the punching process. The small diameter value of the oil hole 532 is smaller than the thickness of the shift block 10, so as to prevent the shift block 10 from being inserted into the oil hole 532, thereby hindering the operation of the push rod 5 and causing damage. The left side of the shift block 10 is provided with a nozzle 101, which is set as a tapered hole with a large diameter end on top, so that the hydraulic oil inside the guide rod 8 has a greater pressure when it is discharged to the second oil hole 62, so that the back pressure formed in the cylinder head 6 can provide sufficient buffering force. The shift block 10 contacts the third hole section 531, the second hole section 521, and the first hole section 511 in sequence during the downward movement of the piston 3.

[0043] As an embodiment of the present invention, refer to Figure 3 The outer contours of the buffer section 513 and the buffer sleeve 4 are both set to be parabolas fitted by three oblique lines. During processing, three inclined planes are first machined out by lathe, and then the surface finish of the buffer section 513 and the buffer sleeve 4 is improved by grinding. In the prior art, the annular gap between the buffer column and the piston 3 has a variety of shapes, and the parabola has the best buffering effect, which can evenly decelerate the buffering process to make the buffering more stable, but the curve is more complex and difficult to process, so a multi-inclined fitting method is adopted. The lower end face of the buffer section 513 and the upper end face of the buffer sleeve 4 are both inclined planes. When the buffer section 513 or the buffer sleeve 4 is just separated from the cylinder head 1 or the cylinder head 6, the hydraulic oil discharged from the first oil hole 11 or the second oil hole 62 will directly act on the upper end face of the buffer section 513 or the upper end face of the buffer sleeve 4, and the original planes of the lower end face of the buffer section 513 and the upper end face of the buffer sleeve 4 are milled into inclined planes, so that the hydraulic oil can be directed to the periphery of the buffer section 513 and the buffer sleeve 4.

[0044] As an embodiment of the present invention, refer to Figure 4, a first groove 5131 is provided at the connection between the buffer section 513 and the upper rod 51, a first protrusion 12 matching the first groove 5131 is provided below the cylinder head 1, a second groove 41 is provided on the buffer sleeve 4, and a second protrusion 61 matching the second groove 41 is provided above the cylinder head 6. The primary function of the first groove 5131 and the second groove 41 is to clean the root to ensure the structural strength of the buffer section 513 and the buffer sleeve 4, and secondly, through the cooperation with the first protrusion 12 and the second protrusion 61, further buffering effect is played, so it should be opened in combination with the actual size of the buffer section 513 and the buffer sleeve 4, not the larger the better. In this solution, it is opened as a semicircle with a cross section and a radius of 3mm.

[0045] As an embodiment of the present invention, refer to Figure 5 The impeller 9 includes a main body 91, blade teeth 92 and blade surfaces 93. The main body 91 is rotatably connected to the inside of the cylinder head 1. A plurality of blade teeth 92 are continuously distributed on the circumference of the main body 91. The blade surfaces 93 are arranged between the blade teeth 92. The blade teeth 92 are arranged in an arc shape, and the bending direction of the blade teeth 92 is the same as the rotation direction of the main body 91. Before the mass production of the impeller 9, the debugging work is very important. By improving the shape of the blade teeth 92 and adjusting the tightness of the rotation between the main body 91 and the cylinder head 1, the pressurization effect of the impeller 9 is in a suitable range.

[0046] As an embodiment of the present invention, refer to Figure 3 The upper end of the guide rod 8 is provided with a fixing sleeve 82, which is welded to the bottom of the cylinder head 1. The fixing sleeve 82 is set as a truncated cone structure with a small bottom surface at the bottom, and is hollow inside. It is welded to the guide rod 8 after wrapping it. The upper part of the dust ring 7 is set as a truncated cone structure with a small bottom surface at the top, and the truncated cone structure is gap-connected with the outer ring of the push rod 5.

[0047] Working principle: The hydraulic cylinder used in the punch press requires different buffer forces due to different hydraulic pressures. The effect caused by different hydraulic pressures is specifically reflected in the downward speed of the piston 3 after the cylinder completes the punching. Since the fixed platform of the workpiece remains unchanged during the punching, this speed often occurs when the piston 3 descends to the "fixed position" of the cylinder 2 (that is, the punching is just completed). (Refer to Figure 6The position of the piston 3 in the middle) and the distance between this "fixed position" and the lower bottom surface inside the cylinder 2 may be called the "braking distance". What the cylinder buffer needs to do is to stop the piston 3 within the "braking distance". Therefore, for the initial velocity of the piston 3 formed by different liquid pressures during buffering, corresponding buffering force braking is required. The difference in liquid pressure comes from the oil pressure at the first oil hole 11, and the downward speed of the piston 3 is directly related to the oil inlet speed at the first oil hole 11. Therefore, this scheme arranges the impeller 9 at the upper end of the first oil hole 11 so that it can discharge the corresponding amount of hydraulic oil to the second oil hole 62 according to the oil speed at the first oil hole 11. On the one hand, it reduces the speed at which the hydraulic oil at the first oil hole 11 enters the cylinder 2, thereby reducing the downward speed of the piston 3; on the other hand, it increases the oil discharge volume of the second oil hole 62, and the second oil hole 62 has a limited aperture, which is bound to further increase the resistance of the hydraulic oil below the piston 3 to be discharged from the second oil hole 62. Through the above two aspects, the cylinder can complete the adjustment of its own buffering force;

[0048] Specifically, initially, the piston 3 is at the upper limit position. At this time, only a part of the piston 3 that is in contact with the cavity of the cylinder head 1 can be subjected to hydraulic pressure. In order to enable the piston 3 to move downward faster, the fixing sleeve 82 is made to have a truncated cone structure with a small bottom surface at the bottom, and then the hydraulic oil discharged from the first oil hole 11 is guided to the lower part of the inner cavity of the cylinder head 1 through the circumferential surface of the fixing sleeve 82, so as to reduce the hydraulic loss caused by the lateral impact of the hydraulic oil on the buffer section 513;

[0049] In the initial stage when the buffer section 513 is separated from the cylinder head 1, the hydraulic oil discharged from the first oil hole 11 will be directly discharged to the upper end surface of the buffer section 513. In order to reduce the backflow and hydraulic loss caused by the impact, the upper end surface of the buffer section 513 is set as an inclined surface, thereby guiding the hydraulic oil discharged to the upper end surface of the buffer section 513 to the periphery of the buffer section 513;

[0050] Reference Figures 6 to 8When the piston 3 descends to the “fixed position”, the channel inside the guide rod 8 needs to be opened to discharge the hydraulic oil at the first oil hole 11 to the second oil hole 62 . The process is as follows: at the initial stage of the piston 3 descending, the shift block 10 contacts the third hole section 531. Since the upper and lower end surfaces of the shift block 10 are long waist circles, and the diameter of the long waist circle is equal to the inner diameter of the third hole section 531, the contact area between the two is large and the contact is stable; moreover, the center axis of the third hole section 531 is on the left side of the center axis of the guide rod 8, and the nozzle 101 is also on the left side of the shift block 10, so the nozzle 101 is outside the guide rod 8, and the inside of the guide rod 8 is in a closed state; when the piston 3 descends to the "fixed position", the shift block 10 begins to contact the second hole section 521, so that the nozzle 101 gradually enters the inside of the guide rod 8, so that the inside of the guide rod 8 gradually opens; when the piston 3 continues to move downward and the shift block 10 contacts the first hole section 511, the inside of the guide rod 8 is completely opened, and the liquid inside the guide rod 8 is pressurized and discharged from the conical nozzle 101 to the inside of the cylinder head 6, and discharged from the second oil hole 62;

[0051] As the piston 3 descends, the space between the first sealing ring 5121 and the second sealing ring 81 will continue to shrink, causing the hydraulic oil between the two to be discharged into the cylinder barrel 2 at the bottom of the piston 3. The oil discharge here occurs before the buffering process, and the hydraulic oil can be discharged smoothly from the second oil hole 62, so it will hardly affect the downward movement of the piston 3; and when the oil discharge here occurs during the buffering process, the discharged hydraulic oil will be discharged from the second oil hole 62 in the above manner, further increasing the buffering force of the buffering process; while the piston 3 enters the buffering process, the buffer sleeve 4 is gradually inserted into the cylinder head 6, and with the help of its own parabolic surface, it can achieve equal deceleration, thereby achieving a more stable buffering effect. Before the end of the buffering, the second protrusion 61 will first enter the second groove 41 to further improve the buffering effect;

[0052] The pressurization from the first oil hole 11 to the second oil hole 62 is achieved through the impeller 9. The pressure of the hydraulic oil driven by the impeller 9 when rotating will increase, and the rotation will encounter resistance. When the guide rod 8 is closed inside, the hydraulic oil driven by the impeller 9 cannot be discharged to the guide rod 8, so the resistance to rotation will be further increased. When the blade surface 93 is facing downward, the impeller 9 will only be subjected to a weak hydraulic power, so it is difficult for the impeller 9 to continue to rotate, that is, the blade surface 93 is kept facing downward, so that the first oil hole 11 can normally enter the oil; when the guide rod 8 is open, since the pressure at the first oil hole 11 is greater than that at the second oil hole 62, the hydraulic oil at the first oil hole 11 will spontaneously flow to the inside of the guide rod 8, and at this time, the tooth surface will continue to rotate driven by the hydraulic oil flowing upward, and as the hydraulic oil drives the blade teeth 92, the rotation speed of the impeller 9 is positively correlated with the descending speed of the piston 3;

[0053] After the downward buffering is completed, oil enters the second oil hole 62, oil is discharged from the first oil hole 11, and the piston 3 moves upward to the upper limit position, and then the above process is repeated.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic cylinder assembly, comprising a cylinder cover (1), a cylinder barrel (2), a piston (3), a buffer sleeve (4), a push rod (5), a cylinder head (6), and a dust ring (7), wherein the cylinder cover (1) and the cylinder head (6) are respectively connected to the upper and lower ends of the cylinder barrel (2), and the cylinder cover (1) and the cylinder head (6) are respectively provided with a first oil hole (11) and a second oil hole (62), the piston (3) slides inside the cylinder barrel (2), the buffer sleeve (4) is connected below the piston (3), the upper and lower ends of the push rod (5) respectively penetrate the piston (3) and the cylinder head (6), and the dust ring (7) is arranged between the cylinder head (6) and the push rod (5), characterized in that: It also includes a guide rod (8), an impeller (9) and a shift block (10); the push rod (5) is hollow inside; the guide rod (8) is connected to the bottom of the cylinder head (1) and inserted into the push rod (5); the upper and lower ends of the guide rod (8) are respectively connected to the first oil hole (11) and the second oil hole (62); the impeller (9) is installed at the upper end of the first oil hole (11); and the shift block (10) is plugged into the lower part of the guide rod (8) along the left-right direction; When the buffer sleeve (4) enters the cylinder head (6), the shift block (10) is pushed by the push rod (5) to gradually open the internal channel of the guide rod (8). The hydraulic oil at the first oil hole (11) drives the impeller (9) to rotate and is pressurized by the impeller (9) to be discharged to the second oil hole (62) through the guide rod (8). The amount of oil discharged to the second oil hole (62) is positively correlated with the oil inlet speed of the first oil hole (11).

2. A hydraulic cylinder assembly according to claim 1, characterized in that: The push rod (5) comprises an upper rod (51), a transition rod (52) and a lower rod (53); a first hole section (511), a second hole section (521) and a third hole section (531) are respectively formed inside the upper rod (51), the transition rod (52) and the lower rod (53); the central axis of the first hole section (511) is on the right side of the central axis of the guide rod (8); the second hole section (521) is a pair of right-angled trapezoids with the same shape, overlapping lower bases and right-angled edges opposite to the central axis of the guide rod (8) on the projection of the longitudinal plane passing through the central axis of the guide rod (8); the central axis of the third hole section (531) is on the left side of the central axis of the guide rod (8); a nozzle (101) is formed on the left side of the shift block (10); and the shift block (10) contacts the third hole section (531), the second hole section (521) and the first hole section (511) in sequence.

3. A hydraulic cylinder assembly according to claim 2, characterized in that: The nozzle (101) is configured as a tapered hole, with the large diameter end of the nozzle (101) being on top.

4. A hydraulic cylinder assembly according to claim 2, characterized in that: The upper and lower end surfaces of the shift block (10) are in the shape of an oblong circle, and the diameter of the oblong circle of the shift block (10) is equal to the diameters of the first hole section (511) and the second hole section (521). An oil hole (532) is provided at the upper end of the lower rod (53), and the oil hole (532) is provided as a tapered hole with a small diameter end connected to the third hole section (531), and the small diameter value of the oil hole (532) is smaller than the thickness of the shift block (10).

5. A hydraulic cylinder assembly according to claim 4, characterized in that: The upper rod (51) further comprises a guide hole (512) and a buffer section (513); the guide hole (512) is arranged above the first hole section (511), and the guide hole (512) is coaxial with the guide rod (8); the buffer section (513) is arranged above the upper rod (51); and a first sealing ring (5121) and a second sealing ring (81) are respectively installed inside the guide hole (512) and at the lower end of the guide rod (8).

6. A hydraulic cylinder assembly according to claim 5, characterized in that: The outer contours of the buffer section (513) and the buffer sleeve (4) are both arranged as parabolas fitted by a plurality of oblique lines, and the lower end surface of the buffer section (513) and the upper end surface of the buffer sleeve (4) are both inclined surfaces.

7. A hydraulic cylinder assembly according to claim 6, characterized in that: A first groove (5131) is provided at the connection between the buffer section (513) and the upper rod (51), a first protrusion (12) matching the first groove (5131) is provided below the cylinder cover (1), a second groove (41) is provided on the buffer sleeve (4), and a second protrusion (61) matching the second groove (41) is provided above the cylinder head (6).

8. The hydraulic cylinder assembly according to claim 1, characterized in that: The impeller (9) comprises a main body (91), blade teeth (92) and a blade surface (93); the main body (91) is rotatably connected to the inside of the cylinder head (1); a plurality of blade teeth (92) are continuously distributed on the circumference of the main body (91); and the blade surface (93) is arranged between the blade teeth (92).

9. A hydraulic cylinder assembly according to claim 8, characterized in that: The blade teeth (92) are arranged in an arc shape, and the bending direction of the blade teeth (92) is the same as the rotation direction of the main body (91).

10. The hydraulic cylinder assembly according to claim 1, characterized in that: A fixing sleeve (82) is provided at the upper end of the guide rod (8), the fixing sleeve (82) is connected to the bottom of the cylinder head (1), and the fixing sleeve (82) is configured as a truncated cone structure with a small bottom surface at the bottom, and the upper part of the dust ring (7) is configured as a truncated cone structure with a small bottom surface at the top.

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