Secondary buffering structure of oil cylinder
By introducing a secondary buffer structure of the buffer shaft and a buffer spring into the cylinder, the impact problem of the existing cylinder when the piston extends and retracts the end is solved, and a smoother buffering effect and higher stability are achieved.
Patent Information
- Application Number
- CN202422326078.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-09-24
AI Technical Summary
The existing oil cylinders have obvious impact when the piston extends and retracts to the end, resulting in poor stability. The existing buffer structure is complex and the coaxiality is difficult to guarantee, which is prone to high pressure spikes, resulting in machine vibration, noise and wear.
The secondary buffer structure of the oil cylinder is adopted, including a buffer shaft and a buffer spring. The buffer shaft is connected to the cylinder barrel through the buffer hole at the bottom of the cylinder. The buffer spring compresses when the buffer shaft reaches its limit position, providing a secondary buffering effect to reduce the impact when the piston comes into contact with the cylinder bottom.
A smoother cushioning effect is achieved, reducing the impact force of the piston assembly when it is round-trip, improving the stability and service life of the oil cylinder, while simplifying the structure and reducing costs.
Smart Images
Figure CN223019102U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a two - stage buffer structure of an oil cylinder, belonging to the technical field of hydraulic cylinders. Background Technique
[0002] At present, when a piston oil cylinder extends and retracts to the end, there will be obvious impact phenomena, resulting in poor stability of the oil cylinder. There are two current solutions. One is to process buffer grooves on the piston and use the buffer grooves to achieve the buffer effect. The disadvantages of this structure are that the number, depth of the buffer grooves and the clearance between the piston and the cylinder barrel are difficult to control, and they have a great influence on the buffer effect. The other is to process buffer holes at the bottom of the cylinder and buffer shafts on the piston rod. Since the buffer effect needs to be ensured, the clearance between the buffer hole and the buffer shaft is very small. This structure has high coaxiality requirements between the bottom of the cylinder and the piston rod, and the bottom of the cylinder basically adopts a welded structure, which makes it difficult to ensure coaxiality. In addition, this structure has another disadvantage: when the buffer shaft extends into the buffer hole, the clearance is too small and the oil flow is not smooth, which will generate a very high pressure peak. The high impact value will cause machine vibration, noise and wear, so it is necessary to add a one - way valve structure, resulting in a complex structure and high failure rate. Content of the Utility Model
[0003] The technical problem to be solved by the utility model is to provide a two - stage buffer structure of an oil cylinder, which can make the buffer effect smoother.
[0004] The technical solution adopted by the utility model to solve its technical problem is: a two - stage buffer structure of an oil cylinder, including the bottom of the cylinder, a buffer shaft, a piston assembly and a cylinder barrel. One end of the cylinder barrel is fixedly connected to the bottom of the cylinder. The side wall of the bottom of the cylinder is provided with a rodless cavity oil port. The inner end of the rodless cavity oil port is communicated with the inner cavity of the cylinder barrel through a buffer hole at the bottom of the cylinder. The axial direction of the buffer hole at the bottom of the cylinder is consistent with the axial direction of the cylinder barrel. One end of the buffer shaft can be inserted into the buffer hole at the bottom of the cylinder with a clearance fit and reciprocate along the axis of the buffer hole at the bottom of the cylinder. The piston assembly is arranged in the cylinder barrel and can reciprocate along the axis of the cylinder barrel. One end of the piston assembly close to the bottom of the cylinder is provided with a guiding blind hole coaxial with the buffer hole at the bottom of the cylinder. The side wall of the buffer shaft is provided with an annular protrusion coaxial with it. The end of the buffer shaft far from the bottom of the cylinder is inserted into the guiding blind hole. The outer peripheral surface of the annular protrusion forms a clearance fit with the guiding blind hole. The buffer shaft is provided with a structure to prevent it from falling off from the guiding blind hole; A buffer spring is coaxially sleeved on the end of the buffer shaft far from the bottom of the cylinder. One end of the buffer spring is butted against the annular protrusion, and the other end is butted against the bottom of the guiding blind hole. When the buffer spring is in the natural state, there is an axial distance between the end face of the end of the buffer shaft inserted into the guiding blind hole and the bottom of the guiding blind hole, and the axial length of the buffer shaft exposed outside the piston assembly is greater than the axial length of the buffer hole at the bottom of the cylinder.
[0005] Further preferably, the piston assembly includes a piston and a piston rod. The piston forms a threaded connection and fixing structure with the outer peripheral surface of the piston rod through an internal threaded hole. Sealing structures are provided between the piston and the outer peripheral surface of the piston rod, and between the piston and the inner wall of the cylinder barrel. The guiding blind hole is provided on the end surface of the piston rod.
[0006] Further preferably, a buffer spacer sleeve is coaxially sleeved on the buffer shaft on the side of the annular protrusion close to the bottom of the cylinder. A spacer sleeve positioning hole is coaxially provided on the piston rod at the position of the end face of the hole opening adjacent to the guiding blind hole. A limiting wall is fixedly provided at the end of the internal threaded hole of the piston close to the bottom of the cylinder. The limiting wall has a through hole for the buffer shaft to pass through. The buffer spacer sleeve is arranged in the spacer sleeve positioning hole, and the buffer spacer sleeve realizes axial positioning through the bottom wall of the spacer sleeve positioning hole and the limiting wall on the piston.
[0007] Further preferably, a plurality of axially oil-through grooves are arranged at intervals along the circumferential direction on the inner wall of the buffer spacer sleeve. The two ends of the axially oil-through grooves intersect with the two axial end faces of the buffer spacer sleeve. At least part of the axially oil-through grooves are provided with radially oil-through grooves communicating the inner wall and the outer wall of the buffer spacer sleeve at the end face position of the buffer spacer sleeve. The radially oil-through grooves are arranged at the end of the buffer spacer sleeve close to the buffer spring. At least one oil-through groove is provided on the outer peripheral surface of the annular protrusion. Each oil-through groove extends along the axial direction of the buffer shaft, and the two ends of the oil-through groove are correspondingly communicated with the two axial end faces of the annular protrusion.
[0008] Further preferably, a radial screw hole is provided on the side wall of the internal threaded hole of the piston. The radial screw hole is provided with a fastening screw, and the piston and the piston rod are locked and fixed by the fastening screw.
[0009] Further preferably, welding fixation is adopted between the cylinder barrel and the bottom of the cylinder; the clearance between the outer peripheral surface of the annular protrusion of the buffer shaft and the guiding blind hole is smaller than the clearance between the end of the buffer shaft inserted into the buffer hole at the bottom of the cylinder and the buffer hole at the bottom of the cylinder.
[0010] Further preferably, the radial cross-section of the buffer shaft is circular, and both the guiding blind hole and the buffer hole at the bottom of the cylinder are circular holes.
[0011] The beneficial effects of the present utility model are as follows: When the piston assembly retracts into the cylinder barrel, it will first drive the buffer shaft to insert into the buffer hole at the bottom of the cylinder, playing a primary buffering role; the buffer shaft moves along with the piston assembly until the buffer shaft reaches the limit value of inserting into the buffer hole at the bottom of the cylinder. Since when the buffer spring is in its natural state, the axial length of the buffer shaft exposed outside the piston assembly is greater than the axial length of the buffer hole at the bottom of the cylinder, when the buffer shaft reaches the limit value of inserting into the buffer hole at the bottom of the cylinder, the piston assembly still does not contact the bottom of the cylinder. When the piston assembly continues to retract into the cylinder barrel, the annular convex part of the buffer shaft will have an axial relative movement with the guiding blind hole of the piston assembly, thereby compressing the buffer spring, and the buffer spring plays a secondary buffering role until the piston assembly reaches the stroke limit when retracting into the cylinder barrel. The present utility model is a double buffering structure with a buffer shaft plus a buffer spring, which can achieve a better buffering effect. And the buffering effect at the end of the stroke when the piston assembly retracts into the cylinder barrel is achieved by the buffer spring. Therefore, the clearance between the buffer shaft and the buffer hole at the bottom of the cylinder can be designed larger (the coaxial position accuracy of the buffer shaft can be ensured by the fitting clearance between the outer peripheral surface of the annular convex part of the buffer shaft and the guiding blind hole). When the buffer shaft enters the buffer hole at the bottom of the cylinder, the oil cylinder will not generate a very high pressure peak. The present utility model has good buffering effect, simple structure, reliable performance and low cost. In addition, since the buffering pressure of the present utility model is only on the buffer spring and has no influence on other parts of the oil cylinder, it can indirectly improve the performance and service life of the oil cylinder. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 is the overall structural schematic diagram of the present utility model;
[0013] Figure 2 is the structural schematic diagram of the bottom of the cylinder of the present utility model;
[0014] Figure 3 is the structural schematic diagram of the buffer shaft of the present utility model;
[0015] Figure 4 is the structural schematic diagram of the buffer spacer of the present utility model;
[0016] Figure 5 is the structural schematic diagram of the piston rod of the present utility model.
[0017] The component marks in the figure are: bottom of the cylinder 1, buffer shaft 2, buffer spacer 3, piston 4, buffer spring 5, piston rod 6, cylinder barrel 7, buffer hole at the bottom of the cylinder 101, rodless cavity oil port 102, primary buffering end of the buffer shaft 201, oil passing groove 202, annular convex 203, spring positioning end 204, axial oil passing groove 301, radial oil passing groove 302, limiting wall 401, spacer positioning hole 601, guiding blind hole 602. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.
[0019] As Figures 1 to 5 shown, the present utility model includes a cylinder bottom 1, a buffer shaft 2, a piston assembly, and a cylinder barrel 7. One end of the cylinder barrel 7 is fixedly connected to the cylinder bottom 1. An end face of the cylinder bottom 1 is provided with a rodless cavity oil port 102. The inner end of the rodless cavity oil port 102 communicates with the inner cavity of the cylinder barrel 7 through a cylinder bottom buffer hole 101. The axial direction of the cylinder bottom buffer hole 101 is consistent with the axial direction of the cylinder barrel 7. One end of the buffer shaft 2 can be inserted into the cylinder bottom buffer hole 101 with a clearance fit and reciprocally move along the axis of the cylinder bottom buffer hole 101. The end of the buffer shaft 2 for inserting into the cylinder bottom buffer hole 101 is the first-stage buffer end 201 of the buffer shaft.
[0020] The piston assembly is arranged inside the cylinder barrel 7 and can reciprocally move along the axis of the cylinder barrel 7. One end of the piston assembly close to the cylinder bottom 1 is provided with a guiding blind hole 602 coaxial with the cylinder bottom buffer hole 101 at the end face. The side wall of the buffer shaft 2 is provided with an annular protrusion 203 coaxial with it. The end of the buffer shaft 2 far from the cylinder bottom 1 is inserted into the guiding blind hole 602. The outer peripheral surface of the annular protrusion 203 forms a clearance fit with the guiding blind hole 602. The buffer shaft 2 is provided with a structure to prevent it from falling off from the guiding blind hole 602; A buffer spring 5 is coaxially sleeved on the end of the buffer shaft 2 far from the cylinder bottom 1. One end of the buffer spring 5 is butted against the annular protrusion 203, and the other end is butted against the bottom of the guiding blind hole 602. The end of the buffer shaft 2 far from the cylinder bottom 1 is the spring positioning end 204.
[0021] When the buffer spring 5 is in the natural state (at this time, the axial length of the buffer shaft 2 exposed outside the piston assembly reaches the maximum value), there is an axial distance between the end face of the end of the buffer shaft 2 inserted into the guiding blind hole 602 and the bottom of the guiding blind hole 602 (the movable space corresponding to this axial distance is the buffer space for the buffer spring 5 to play a secondary buffer role), and the axial length of the buffer shaft 2 exposed outside the piston assembly is greater than the axial length of the cylinder bottom buffer hole 101. Figure 1In the preferred embodiment shown, the "axial length of the buffer shaft 2 exposed outside the piston assembly" refers to the "axial length of the buffer shaft 2 exposed outside the end face of the piston 4", and the "axial length of the bottom buffer hole 101 of the cylinder" refers to the "limit value of the length of the buffer shaft 2 inserted into the bottom buffer hole 101 of the cylinder". When the piston assembly retracts into the cylinder barrel 7, it will first drive the buffer shaft 2 to insert into the bottom buffer hole 101 of the cylinder, playing a primary buffering role; the buffer shaft 2 moves with the piston assembly until the buffer shaft 2 reaches the limit value of inserting into the bottom buffer hole 101 of the cylinder. Since when the buffer spring 5 is in its natural state, the axial length of the buffer shaft 2 exposed outside the piston assembly is greater than the axial length of the bottom buffer hole 101 of the cylinder, when the buffer shaft 2 reaches the limit value of inserting into the bottom buffer hole 101 of the cylinder, the piston assembly still does not contact the bottom of the cylinder 1. When the piston assembly continues to retract into the cylinder barrel 7, the annular protrusion 203 part of the buffer shaft 2 will generate an axial relative movement with the guiding blind hole 602 of the piston assembly, thereby compressing the buffer spring 5, and the buffer spring 5 plays a secondary buffering role, and finally until the piston assembly reaches the stroke limit when retracting into the cylinder barrel 7.
[0022] It can be understood that the key parameter of the primary buffering role is the clearance fit between the primary buffer end 201 of the buffer shaft and the bottom buffer hole 101 of the cylinder. The recommended unilateral clearance is 0.05 mm - 0.9 mm, and different clearances can be reasonably selected according to the actual situation to achieve different primary buffering forces. The key parameters of the secondary buffering role are the wire diameter and pitch of the buffer spring 5. The recommended wire diameter is 1.0 mm - 3.0 mm, and the wire diameter and pitch of the buffer spring 5 can be reasonably selected according to the actual situation to adjust the secondary buffering force.
[0023] The piston assembly generally includes a piston 4 and a piston rod 6. It can be understood that according to the different external shapes of the piston assembly, the guiding blind hole 602 can be designed on the piston 4, or on the piston rod 6, or on both the piston 4 and the piston rod 6 at the same time. For the convenience of assembly, the preferred structural method adopted in the present invention is that the piston 4 forms a threaded connection and fixing structure with the outer peripheral surface of the piston rod 6 through an internal threaded hole. Sealing structures are provided between the outer peripheral surface of the piston 4 and the piston rod 6, and between the piston 4 and the inner wall of the cylinder barrel 7. The guiding blind hole 602 is arranged on the end face of the piston rod 6. In order to improve the connection reliability between the piston 4 and the piston rod 6, the piston 4 can be provided with a radial threaded hole on the side wall of the internal threaded hole. The radial threaded hole is provided with a fastening screw, and the piston 4 and the piston rod 6 are locked and fixed by the fastening screw. The "radial threaded hole" refers to that its axis is arranged along the radial direction of the piston 4.
[0024] Preferably, a buffer spacer sleeve 3 is coaxially sleeved on the buffer shaft 2 on the side of the annular protrusion 203 close to the bottom of the cylinder 1. A spacer sleeve positioning hole 601 is coaxially arranged at the position of the end face of the piston rod 6 adjacent to the orifice of the guiding blind hole 602. A limiting wall 401 is fixedly arranged at one end of the internal threaded hole of the piston 4 close to the bottom of the cylinder 1. The limiting wall 401 has a through hole for the buffer shaft 2 to pass through. The buffer spacer sleeve 3 is arranged in the spacer sleeve positioning hole 601. The buffer spacer sleeve 3 realizes axial limitation through the bottom wall of the spacer sleeve positioning hole 601 and the limiting wall 401 on the piston 4. The buffer spacer sleeve 3 can prevent the buffer shaft 2 from falling off from the guiding blind hole 602 and prevent the annular protrusion 203 part of the buffer shaft 2 from directly impacting the piston 4. It can be understood that in some alternative embodiments, the limiting wall 401 of the piston 4 can also directly prevent the buffer shaft 2 from falling off from the guiding blind hole 602; additional stroke limiting parts can also be added to prevent the buffer shaft 2 from falling off from the guiding blind hole 602.
[0025] Preferably, a plurality of axial oil through grooves 301 ( Figure 4 in the preferred embodiment, four are arranged at equal intervals) are arranged at intervals along the circumferential direction of the inner wall of the buffer spacer sleeve 3. The two ends of the axial oil through grooves 301 intersect with the two axial end faces of the buffer spacer sleeve 3. At least part of the axial oil through grooves 301 ( Figure 4 in the preferred embodiment, two of them arranged symmetrically are selected) are provided with radial oil through grooves 302 connecting the inner wall and the outer wall of the buffer spacer sleeve 3 at the end face position of the buffer spacer sleeve 3. The radial oil through grooves 302 are arranged at one end of the buffer spacer sleeve 3 close to the buffer spring 5. At least one oil through groove 202 ( Figure 3 in the preferred embodiment, two are designed to be arranged symmetrically) is arranged on the outer peripheral surface of the annular protrusion 203. Each oil through groove 202 extends along the axial direction of the buffer shaft 2. The two ends of the oil through groove 202 are correspondingly communicated with the two axial end faces of the annular protrusion 203. By arranging the axial oil through grooves 301, the radial oil through grooves 302 and the oil through grooves 202, when the piston assembly moves out or the buffer shaft 2 enters the buffer area, the oil can still enter the area where the buffer spring 5 is located smoothly, so that the buffer shaft 2 is subjected to a backward thrust, avoiding sudden or excessive compression of the spring 9 and improving the service life of the buffer spring 5. Specifically, the cross-sectional forms of the axial oil through grooves 301, the radial oil through grooves 302 and the oil through grooves 202 are not limited and can be rectangular, R-arc-shaped, V-shaped, etc.
[0026] For the convenience of machining and assembly, the clearance between the outer peripheral surface of the annular protrusion 203 of the buffer shaft 2 and the guiding blind hole 602 is smaller than the clearance between the end of the buffer shaft 2 inserted into the buffer hole 101 at the bottom of the cylinder and the buffer hole 101 at the bottom of the cylinder. The coaxial position accuracy of the buffer shaft 2 is effectively ensured mainly by the small clearance fit between the outer peripheral surface of the annular protrusion 203 of the buffer shaft 2 and the guiding blind hole 602. This fit method is particularly applicable to the scheme where the cylinder barrel 7 and the cylinder bottom 1 are fixed by welding. For example, in some embodiments, the unilateral clearance between the end of the buffer shaft 2 inserted into the buffer hole 101 at the bottom of the cylinder and the buffer hole 101 at the bottom of the cylinder can be designed to be 0.4 mm, and the unilateral clearance between the outer peripheral surface of the annular protrusion 203 of the buffer shaft 2 and the guiding blind hole 602 can be designed to be 0.15 mm.
[0027] For the convenience of machining and assembly, the radial cross-section of the buffer shaft 2 is circular, and both the guiding blind hole 602 and the buffer hole 101 at the bottom of the cylinder are circular holes. Correspondingly, the spacer positioning hole 601 is preferably a circular hole, and the buffer spacer 3 is preferably a circular ring structure.
Claims
1. A secondary buffer structure of an oil cylinder, comprising a cylinder bottom (1), a buffer shaft (2), a piston assembly and a cylinder barrel (7), wherein one end of the cylinder barrel (7) is fixedly connected to the cylinder bottom (1), a side wall of the cylinder bottom (1) is provided with a rodless cavity oil port (102), an inner end of the rodless cavity oil port (102) is communicated with an inner cavity of the cylinder barrel (7) through a cylinder bottom buffer hole (101), an axial direction of the cylinder bottom buffer hole (101) is consistent with an axial direction of the cylinder barrel (7), one end of the buffer shaft (2) can be inserted into the cylinder bottom buffer hole (101) with clearance fit and reciprocate along the axis of the cylinder bottom buffer hole (101), the piston assembly is provided in the cylinder barrel (7) and can reciprocate along the axis of the cylinder barrel (7), and is characterized in that: The end of the piston assembly close to the cylinder bottom (1) is provided with a guide blind hole (602) coaxial with the cylinder bottom buffer hole (101) at the end surface, the side wall of the buffer shaft (2) is provided with an annular protrusion (203) coaxial with the cylinder bottom buffer hole (101), the end of the buffer shaft (2) away from the cylinder bottom (1) is inserted into the guide blind hole (602), and the outer peripheral surface of the annular protrusion (203) forms a clearance fit with the guide blind hole (602); the buffer shaft (2) is provided with a structure to prevent it from falling out of the guide blind hole (602); the buffer shaft ( 2) A buffer spring (5) is coaxially sleeved at one end away from the cylinder bottom (1), one end of the buffer spring (5) is butted against the annular protrusion (203), and the other end is butted against the bottom of the guide blind hole (602). When the buffer spring (5) is in a natural state, an end face of the buffer shaft (2) inserted into the guide blind hole (602) has an axial spacing with the bottom of the guide blind hole (602), and the axial length of the buffer shaft (2) exposed outside the piston assembly is greater than the axial length of the buffer hole (101) at the cylinder bottom.
2. The oil cylinder secondary buffer structure according to claim 1, characterized in that: The piston assembly comprises a piston (4) and a piston rod (6); the piston (4) forms a threaded connection fixing structure with the outer peripheral surface of the piston rod (6) through an internal threaded hole; sealing structures are provided between the piston (4) and the outer peripheral surface of the piston rod (6) and between the piston (4) and the inner wall of the cylinder (7); and a guide blind hole (602) is provided on the end surface of the piston rod (6).
3. The oil cylinder secondary buffer structure according to claim 2, characterized in that: The buffer shaft (2) is coaxially provided with a buffer spacer (3) on one side of the annular protrusion (203) close to the cylinder bottom (1); the piston rod (6) is coaxially provided with a spacer positioning hole (601) at a position close to the orifice end face of the guide blind hole (602); the internal threaded hole of the piston (4) is fixedly provided with a limiting wall (401) at one end close to the cylinder bottom (1); the limiting wall (401) has a through hole for the buffer shaft (2) to pass through; the buffer spacer (3) is arranged in the spacer positioning hole (601); the buffer spacer (3) is axially limited by the bottom wall of the spacer positioning hole (601) and the limiting wall (401) on the piston (4).
4. The oil cylinder secondary buffer structure according to claim 3, characterized in that: The inner wall of the buffer sleeve (3) is provided with a plurality of axial oil grooves (301) arranged at intervals along its circumference, and the two ends of the axial oil grooves (301) intersect with the two axial end faces of the buffer sleeve (3), and at least part of the axial oil grooves (301) are provided with radial oil grooves (302) connecting the inner wall and the outer wall of the buffer sleeve (3) at the end face position of the buffer sleeve (3), and the radial oil grooves (302) are arranged at one end of the buffer sleeve (3) close to the buffer spring (5), and the outer peripheral surface of the annular protrusion (203) is provided with at least one oil groove (202), and each oil groove (202) is arranged along the axial extension of the buffer shaft (2), and the two ends of the oil groove (202) are correspondingly connected with the two axial end faces of the annular protrusion (203).
5. The oil cylinder secondary buffer structure according to claim 2, characterized in that: The piston (4) is provided with a radial screw hole on the side wall of the internal threaded hole, and the radial screw hole is equipped with a fastening screw, through which the piston (4) and the piston rod (6) are locked and fixed.
6. The oil cylinder secondary buffer structure according to claim 1, characterized in that: The cylinder barrel (7) and the cylinder bottom (1) are fixed by welding; the fitting clearance between the outer peripheral surface of the annular protrusion (203) of the buffer shaft (2) and the guide blind hole (602) is smaller than the fitting clearance between the end of the buffer shaft (2) inserted into the cylinder bottom buffer hole (101) and the cylinder bottom buffer hole (101).
7. The oil cylinder secondary buffer structure according to any one of claims 1 to 6, characterized in that: The radial cross section of the buffer shaft (2) is circular, and the guide blind hole (602) and the cylinder bottom buffer hole (101) are both circular holes.