A hydraulic hold down device

Abstract

The hydraulic pressing device comprises a base body, a pressing mechanism, and a pre-positioning mechanism. The base body has a cylinder hole at one end and a variable-diameter through hole at the other end. The pressing mechanism comprises a connecting plate, a piston rod located in the cylinder hole of the base body, a top pin, a threaded plug, and an end cover. The pre-positioning mechanism comprises a guide shaft, a guide sleeve, and a connecting shaft. The threaded plug is fixed at the inner end of the piston rod, the top pin is slidably and slightly-clearance-fitted in the central variable-diameter hole of the piston rod, a pressure spring is arranged between the top pin and the threaded plug, the guide sleeve is interference-fitted at one end of the variable-diameter through hole of the base body, the guide shaft is slidably and slightly-clearance-fitted in the guide sleeve, the connecting shaft is press-bonded to the spring in the groove at the upper end of the guide shaft, and is controlled to be extended and retracted by a spring plunger controller. The top pin and the guide shaft are connected together through the connecting plate. The hydraulic pressing device can press and position a workpiece, has the pre-positioning function, is stable and reliable, has high installation performance, has a compact structure and small size, is easy to install and operate, and is very convenient to use.

Description

Technical Field

[0001] This invention belongs to the field of machining and relates to a hydraulic clamping device. Background Technology

[0002] In machining, it is common to encounter situations where workpieces need to be positioned and clamped by holes before machining. The traditional method is to rigidly fix the center directly to the piston rod and use a hydraulic cylinder to drive the center to clamp it. This requires an additional pre-positioning mechanism to ensure the relative position of the center and the hole on the workpiece is stable. This not only makes the clamping structure bulky and complicated, but also creates additional difficulties for the machining of the workpiece. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a hydraulic clamping device. This device has a pre-positioning function. The device itself can not only pre-position the positioning hole on the workpiece, but also clamp and position the workpiece. When pre-positioning, it is easy to enter the workpiece positioning hole. When clamping and positioning the workpiece, it is stable and reliable. The structure is compact and the volume is relatively small. The workpiece is easy to install and process, and it is very convenient to use.

[0004] To achieve the above objectives, the technical solution of the present invention is: a hydraulic clamping device, comprising a base, a clamping mechanism, and a pre-positioning mechanism; a cylinder bore is opened at one end of the base, and a variable diameter through hole is opened at the other end; the clamping mechanism includes a connecting plate, a piston rod located in the cylinder bore at one end of the base, a center, a threaded plug, and an end cap; the upper end of the piston rod is slidably connected to the cylinder bore of the base through a sealing ring I, and its lower end is slidably connected to the center hole of the end cap through a sealing ring II; the base is provided with an oil outlet and a retraction port respectively communicating with the upper and lower ends of its cylinder bore; the end cap is sealed and fixed in place. The cylinder bore end of the base body; the piston rod has a central stepped hole with a threaded upper end; the outer end of the center tip is provided with a positioning step that matches the outer end face of the piston rod, and the outer end of the center tip outside the positioning step is set in a shape that matches the positioning hole of the workpiece and the tip transitions to a tapered shape; the threaded plug is threadedly fixed to the upper end of the central diameter-changing hole of the piston rod, and the diameter of its optical axis portion located in the central diameter-changing hole is smaller than that of the central diameter-changing hole of the piston rod; the center tip is slidably and micro-clearly assembled in the central diameter-changing hole of the piston rod, and its outer end passes through the fixing hole at one end of the connecting plate and is fixed to the connecting plate, and its other end... A pressure spring is fitted onto the optical shaft portion of the threaded plug. The spring force ensures that the tip does not retract with the piston rod when it retracts and remains in its original position. The pre-positioning mechanism includes a guide shaft, a guide sleeve, and a connecting shaft located within the variable diameter through hole of the base. The guide sleeve is interference-fitted into one end of the variable diameter through hole of the base. The guide shaft is slidably and slightly clearance-fitted into the guide sleeve. One end of the guide shaft is fixed to the other end of the connecting plate, and the other end has a mounting groove. A spring is located in the mounting groove. The connecting shaft is placed within the variable diameter through hole of the base, and one end of it is slidably and slightly clearance-fitted into the mounting groove of the guide shaft within a certain range. The end face of the connecting shaft is pressed against the spring, and the other end of the connecting shaft passes through the variable diameter through hole of the base. The outer circle of the other end has a sliding groove for the spring plunger. A connecting block is fixed on the base where the connecting shaft passes through the variable diameter through hole of the base. The connecting block has a connecting shaft through hole and a threaded hole that are perpendicular to each other. The connecting shaft passes through the connecting shaft through hole of the connecting block. The spring plunger is pressed and fixed in the threaded hole of the connecting block by a nut and abuts against the sliding groove of the connecting shaft. The sliding groove of the connecting shaft has groove I and groove II at both ends to limit the spring plunger. Groove I and groove II correspond to the two states of the tip being pushed out and retracted, respectively.

[0005] More preferably, the specific structure of the upper end of the tip is as follows: a threaded hole I is opened on the upper end face of the tip, a U-shaped pad with a through hole in the center is fastened to the upper end of the tip, and the U-shaped pad is fixed to the tip by a screw I; the pressure spring is sleeved on the optical axis part of the threaded plug and outside the screw I. This structure of the upper end of the tip is easy to install and easy to disassemble.

[0006] More preferably, the specific structure of the upper end of the tip is as follows: the upper end of the tip is tapered and protrudes with a limiting protrusion; the pressure spring is sleeved on the optical axis portion of the threaded plug and the fine part of the upper end of the tip.

[0007] More preferably, the connecting shaft consists of connecting shaft I and connecting shaft II; connecting shaft II and connecting shaft I are connected in a T-shape, and connecting shaft II and connecting shaft I respectively have T-shaped limiting grooves and T-shaped protrusions or T-shaped protrusions and T-shaped limiting grooves that cooperate with each other; a handle is fixed to the outer end of connecting shaft II.

[0008] More preferably, the structure in which one end of the connecting shaft can be slidably fitted into the mounting groove of the guide shaft within a certain range with a slight gap is as follows: symmetrically distributed cylindrical pin sliding grooves are formed on the inner wall of the mounting groove of the guide shaft, and a cylindrical pin is fixed on the connecting shaft I, with both ends of the cylindrical pin placed within the two cylindrical pin sliding grooves. In this way, the connecting shaft can slide along the mounting groove of the guide shaft within the length of the cylindrical pin sliding grooves.

[0009] More preferably, the outer end face of the piston rod is a positioning conical surface I, and the side of the positioning step at the tip that faces the outer end face of the piston rod is a positioning conical surface II that mates with positioning conical surface I. The position where the piston rod and the tip face each other is a conical fit, which reduces component damage caused by hard impact.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] The device of this invention incorporates a pre-positioning mechanism and slides elastically to connect the piston rod within the cylinder bore of the base to the center. The center not only positions and clamps the workpiece but also pre-positions it under the action of the pre-positioning mechanism. This eliminates the need for an additional pre-positioning mechanism, significantly simplifying the structure of existing workpiece clamping and positioning devices. The device of this invention has a compact structure and relatively small size, making it easy to install and operate on the workpiece, and is very convenient to use. Furthermore, the overall structure of this invention has sufficient rigidity, allowing for easy entry into the workpiece positioning hole during pre-positioning and stable and reliable clamping and positioning of the workpiece. This invention greatly improves production efficiency, reduces the operator's workload, is safe and reliable to use, and creates favorable conditions for workpiece machining. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0013] Figure 2 This is the front view of the present invention;

[0014] Figure 3 for Figure 2 AA section view;

[0015] Figure 4 This is the left view of the present invention;

[0016] Figure 5 for Figure 4 BB section view;

[0017] Figure 6 for Figure 4 CC section view;

[0018] Figure 7 for Figure 3 A schematic diagram of the structure when the tip is ejected;

[0019] Figure 8 This is a three-dimensional structural diagram of the connecting plate in this invention;

[0020] Figure 9 This is a schematic diagram of the top three-dimensional structure of the present invention;

[0021] Figure 10 This is a three-dimensional structural diagram of the piston rod in this invention. Detailed Implementation

[0022] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 10 As shown, this embodiment includes a base 1, a clamping mechanism, and a pre-positioning mechanism. One end of the base 1 has a cylinder hole, and the other end has a variable-diameter through hole.

[0024] The clamping mechanism includes a connecting plate 5, a piston rod 3 located in the cylinder bore at one end of the base 1, a center 4, a threaded plug 16, and an end cap 2. The upper end of the piston rod 3 is slidably connected to the cylinder bore of the base 1 via a sealing ring I 20, and its lower end is slidably connected to the center hole of the end cap 2 via a sealing ring II 17. The base 1 is provided with an oil outlet 29 and a retraction oil outlet 30 that communicate with the upper and lower ends of its cylinder bore, respectively. The end cap 2 is sealed and fixed to the end of the cylinder bore of the base 1 via a sealing ring III 18 and a screw III 25. A dustproof ring 17 is provided at the end between the end cap 2 and the piston rod 3 to prevent dust from entering. The piston rod 3 has a central stepped hole with threads at the upper end, and the outer end face of the piston rod 3 is a positioning cone surface I. The outer end of the tip 4 is provided with a positioning step 31 that matches the outer end face of the piston rod 3. The side of the positioning step 31 opposite to the outer end face of the piston rod 3 is a positioning cone surface II that mates with the positioning cone surface I. The outer end of the tip 4 outside the positioning step 31 is configured to match the positioning hole of the workpiece, and the tip transitions to a cone shape. In this embodiment, the outer end of the tip 4 is configured as a square with a transition connecting surface, and the tip transitions to a square pyramid with a transition connecting surface, which facilitates the tip 4 entering and exiting the positioning hole of the workpiece and reduces the contact area when in contact with the positioning hole, thus avoiding any protrusions or burrs that may exist on the tip 4 and the workpiece. The threaded plug 16 is threadedly fixed to the upper end of the central reducing hole of the piston rod 3, and the diameter of the optical axis portion located in the central reducing hole is smaller than that of the central reducing hole of the piston rod 3. The tip 4 is slidably fitted into the central variable-diameter hole of the piston rod 3 with a micro-gap. Its outer end passes through the fixing hole at one end of the connecting plate 5 and is fixed to the connecting plate 5 by the open retaining ring 24. A pressure spring 22 is fitted on the other end and the optical axis of the threaded plug 16. The elastic force of the pressure spring 22 ensures that the tip 4 does not retract with the piston rod 3 when the piston rod 3 retracts and remains in its original position. In this embodiment, the fixing hole of the connecting plate 5 is a square hole that matches the square shape of the outer end of the tip 4. In order to facilitate the installation and disassembly of the upper end of the tip 4, the specific structure of the upper end of the tip 4 is as follows: a threaded hole I is opened on the upper end face of the tip 4, a U-shaped pad 28 with a through hole in the center is fastened to the upper end of the tip 4, and the U-shaped pad 28 is fixed to the tip 4 by screw I 19; the pressure spring 22 is fitted on the lower end of the threaded plug 16 and the screw I 19. Another specific structure of the upper end of the tip 4 is: the upper end of the tip 4 is tapered and protrudes with a limiting protrusion; the pressure spring 22 is sleeved on the lower end of the threaded plug 16 and the fine part of the upper end of the tip 4.

[0025] The pre-positioning mechanism includes a guide shaft 6, a guide sleeve 8, and a connecting shaft located within the variable-diameter through hole of the base 1. The guide sleeve 8 is interference-fitted into one end of the variable-diameter through hole of the base 1. The guide shaft 6 is slidably and slightly clearance-fitted into the guide sleeve 8; one end of the guide shaft 6 is fixed to the other end of the connecting plate 5 by screw IV 15, and the other end has a mounting groove; a spring 14 is located within the mounting groove. To ensure ease of installation, the connecting shaft consists of connecting shaft I 7 and connecting shaft II 9; connecting shaft II 9 and connecting shaft I 7 are connected in a T-shape, and each has a mutually cooperating T-shaped limiting groove and a T-shaped protrusion, or a T-shaped protrusion and a T-shaped limiting groove; a handle 10 is fixed to the outer end of connecting shaft II 9, ensuring convenient push-pull operation. Connecting shaft II 9 and connecting shaft I 7 are placed within the variable-diameter through hole of the base 1. One end of connecting shaft I 7 is slidably and slightly clearance-fitted into the mounting groove of the guide shaft 6 within a certain range, and its end face is pressed against the spring 14. The specific structure of the connecting shaft I7, which can be slidably fitted into the mounting groove of the guide shaft 6 within a certain range with a slight clearance, is as follows: Symmetrically distributed cylindrical pin sliding grooves are formed on the inner wall of the mounting groove of the guide shaft 6. A cylindrical pin 13 is fixed on the connecting shaft I7, with both ends of the cylindrical pin 13 placed within the two cylindrical pin sliding grooves. Thus, the connecting shaft I7 can slide along the mounting groove of the guide shaft 6 within the length of the cylindrical pin sliding grooves. The connecting shaft II9 protrudes through the variable diameter through hole of the base 1, and a sliding groove for a spring plunger 11 is formed on its outer circumference. A connecting block 27 is fixed to the base 1 at the point where the connecting shaft II9 protrudes through the variable diameter through hole of the base 1 by screw II 26. The connecting block 27 has mutually perpendicular connecting shaft through holes and threaded holes. The connecting shaft II9 passes through the connecting shaft through hole of the connecting block 27. The spring plunger 11 is pressed and fixed in the threaded hole of the connecting block 27 by the nut 12 and abuts against the sliding groove of the connecting shaft II9. The sliding groove of the connecting shaft II9 has groove I and groove II at both ends to limit the spring plunger 11. Groove I and groove II correspond to the two states of the tip 4 being pushed out and retracted, respectively.

[0026] In use, the cylinder bore on the base 1 serves as the center reference of the hydraulic clamping device. It can be connected to other fixed mechanisms for positioning according to different operating conditions, enabling the workpiece to be pre-positioned, positioned, and clamped using the positioning holes on the workpiece. When the device is working, first roughly align the hole on the workpiece with the position of the tip 4, then manually push down the handle 10, with the spring plunger 11 limiting the downward push. The connecting shaft and guide shaft 6 drive the connecting plate 5 to slide downwards, which in turn drives the tip 4 to slide downwards. Simultaneously, under the force of the pressure spring 22, the tip 4 contacts and penetrates the positioning hole on the workpiece, thus pre-positioning the workpiece. Then, oil is supplied through the ejector port, and the piston rod 3 slides downwards until it clamps the tip 4. At this point, the tip 4 positions and clamps the workpiece. Figure 7As shown. When the oil supply port is retracted, the piston rod 3 retracts, and under the action of the pressure spring 22, the tip 4 remains stationary. At this time, the tip 4 only has a pre-positioning function. Then, the handle 10 is manually pulled upward, and the connecting shaft drives the guide shaft 6 and the connecting rod 5 to slide upward, thereby causing the tip 4 to disengage from the positioning hole on the workpiece. This device is completely separated from the workpiece. The spring 14 acts as a buffer between the connecting shaft and the guide shaft 6. When the connecting shaft is pushed down into place, the guide shaft 6 can slide down further under the action of the spring 14, and the connecting plate 5 has a certain pressing effect on the tip 4.

[0027] Of course, there are other embodiments of the present invention. Without departing from the spirit and essence of the present invention, those skilled in the art can make corresponding changes and modifications according to the present invention. However, these corresponding changes and modifications should all be considered improvements of equivalent technology and fall within the protection scope of the claims of the present invention.

Claims

1. A hydraulic clamping device, characterized in that: The system includes a base (1), a clamping mechanism, and a pre-positioning mechanism; the base (1) has a cylinder bore at one end and a variable diameter through hole at the other end; the clamping mechanism includes a connecting plate (5), a piston rod (3) located in the cylinder bore at one end of the base (1), a center point (4), a threaded plug (16), and an end cap (2); the upper end of the piston rod (3) is slidably connected to the cylinder bore of the base (1) through a sealing ring I (20), and its lower end is slidably connected to the center hole of the end cap (2) through a sealing ring II (17); the base (1) is provided with an oil outlet (29) and a retraction oil outlet (30) respectively connected to the upper and lower ends of its cylinder bore; the end cap (2) is sealed and fixed to the cylinder bore end of the base (1); the piston rod (3) is located in the cylinder bore at one end of the base (1); the piston rod (3) is located in the cylinder bore at one end of the base (1). The center has a central stepped hole with a threaded upper end; the outer end of the center (4) is provided with a positioning step (31) that matches the outer end face of the piston rod (3), and the outer end of the center (4) outside the positioning step (31) is set in a shape that matches the positioning hole of the workpiece and the tip transitions to a tapered shape; the threaded plug (16) is threadedly fixed to the upper end of the central variable diameter hole of the piston rod (3), and the diameter of the optical axis part located in the central variable diameter hole is smaller than that of the central variable diameter hole of the piston rod (3); the center (4) is slidably and micro-clearly fitted into the central variable diameter hole of the piston rod (3), and its outer end passes through the fixing hole at one end of the connecting plate (5) and is fixed on the connecting plate (5), and its other end and the optical axis part of the threaded plug (16) are fitted with A pressure spring (22) ensures that the tip (4) does not retract with the piston rod (3) and remains in its original position when the piston rod (3) retracts; the pre-positioning mechanism includes a guide shaft (6), a guide sleeve (8), and a connecting shaft located in the variable diameter through hole of the base (1); the guide sleeve (8) is interference-fitted into one end of the variable diameter through hole of the base (1); the guide shaft (6) is slidably and slightly clearance-fitted into the guide sleeve (8); one end of the guide shaft (6) is fixed to the other end of the connecting plate (5), and the other end has a mounting groove; a spring (14) is in the mounting groove; the connecting shaft is placed in the variable diameter through hole of the base (1), and one end of it is slidably and slightly clearance-fitted into the mounting groove of the guide shaft (6) within a certain range and the end The other end of the spring is pressed against the spring (14), and the other end of the spring plunger (1) passes through the variable diameter through hole of the base (1). The outer circle of the other end has a sliding groove for the spring plunger (11). A connecting block (27) is fixed on the base (1) at the point where the connecting shaft passes through the variable diameter through hole of the base (1). The connecting block (27) has a connecting shaft through hole and a threaded hole that are perpendicular to each other. The connecting shaft passes through the connecting shaft through hole of the connecting block (27). The spring plunger (11) is pressed and fixed in the threaded hole of the connecting block (27) by the nut (12) and is pressed against the sliding groove of the connecting shaft. The sliding groove of the connecting shaft has groove I and groove II at both ends to limit the spring plunger (11). Groove I and groove II correspond to the two states of the tip (4) being pushed out and retracted, respectively.

2. The hydraulic clamping device according to claim 1, characterized in that: The specific structure of the upper end of the tip (4) is as follows: the upper end face of the tip (4) has a threaded hole I, and a U-shaped pad (28) with a through hole in the center is fastened to the upper end of the tip (4), and the U-shaped pad (28) is fixed to the tip (4) by screw I (19); the pressure spring (22) is sleeved on the optical axis part of the threaded plug (16) and outside the screw I (19).

3. The hydraulic clamping device according to claim 1, characterized in that: The specific structure of the upper end of the tip (4) is as follows: the upper end of the tip (4) is thinner and protrudes a limiting protrusion; the pressure spring (22) is sleeved on the optical axis part of the threaded plug (16) and the fine part of the upper end of the tip (4).

4. The hydraulic clamping device according to claim 1 or 2, characterized in that: The connecting shaft consists of connecting shaft I (7) and connecting shaft II (9); connecting shaft II (9) and connecting shaft I (7) are connected in a T-shape, and connecting shaft II (9) and connecting shaft I (7) have T-shaped limiting grooves and T-shaped protrusions or T-shaped protrusions and T-shaped limiting grooves that cooperate with each other; a handle (10) is fixed to the outer end of connecting shaft II (9).

5. The hydraulic clamping device according to claim 3, characterized in that: The structure in which one end of the connecting shaft can be slidably fitted into the mounting groove of the guide shaft (6) within a certain range is as follows: symmetrical cylindrical pin sliding grooves are opened on the inner wall of the mounting groove of the guide shaft (6), and cylindrical pins (13) are fixed on the connecting shaft I (7), with both ends of the cylindrical pins (13) placed in the two cylindrical pin sliding grooves.

6. The hydraulic clamping device according to claim 4, characterized in that: The outer end face of the piston rod (3) is the positioning cone surface I, and the side of the positioning step (31) of the tip (4) opposite to the outer end face of the piston rod (3) is the positioning cone surface II that matches the positioning cone surface I.

7. The hydraulic clamping device according to claim 3, characterized in that: The outer end face of the piston rod (3) is the positioning cone surface I, and the side of the positioning step (31) of the tip (4) opposite to the outer end face of the piston rod (3) is the positioning cone surface II that matches the positioning cone surface I.

8. The hydraulic clamping device according to claim 1 or 2, characterized in that: The outer end face of the piston rod (3) is the positioning cone surface I, and the side of the positioning step (31) of the tip (4) opposite to the outer end face of the piston rod (3) is the positioning cone surface II that matches the positioning cone surface I.

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