Coaxial automatic clamping fixture for shaft workpieces

Abstract

The utility model discloses a coaxial automatic clamping fixture for shaft workpieces, the clamping fixture is of a pneumatic chuck structure and comprises a pneumatic chuck and pneumatic clamping jaws arranged on the pneumatic chuck at intervals in the circumferential direction, the pneumatic chuck movably and coaxially corresponds to a machine tool chuck, and each pneumatic clamping jaw synchronously follows the direction of the external force under the action of the external force. Each pneumatic clamping jaw is arranged to synchronously follow up with the direction of the external force under the action of the external force, the external force causes the axial deflection effect of the workpiece when the workpiece blank is clamped by a machine tool chuck, and after the deflection acting force acts on the pneumatic clamping jaws, the pneumatic clamping jaws synchronously follow up with the deflection effect. Therefore, the problems that due to the fact that the clamping force of an existing pneumatic clamping jaw is opposite to the deflection force of a workpiece, the assembling gap of the pneumatic clamping jaw is too large, the workpiece clamping error is increased, and the pneumatic clamping jaw is prone to damage are solved.

Description

Technical Field

[0001] This application relates to the technical field of machining and clamping of shaft workpieces, and particularly relates to a coaxial automatic clamping fixture for shaft workpieces. Background Art

[0002] The machining of shaft workpieces is a common and important part of mechanical manufacturing, which involves multiple steps and processes to ensure that the shaft parts meet the required dimensional accuracy, shape accuracy, and surface quality. Selecting machining equipment such as lathes, milling machines, grinding machines, etc., can complete machining operations such as outer circles, inner holes, and end faces, with high machining accuracy and surface quality.

[0003] Currently, to improve the efficiency and progress of batch machining of shaft workpieces, automated clamping of workpieces is adopted, including using automatic clamping fixtures to achieve automated clamping and unloading operations of blanks and processed products. Common clamping fixtures are as shown in the attached Figure 1 description. It is a pneumatic chuck structure, including a pneumatic chuck and pneumatic jaws circumferentially spaced thereon, and the pneumatic chuck is movably coaxially corresponding to the machine tool chuck. As shown in Figure 1 description, there are two pneumatic chucks vertically arranged, and a displacement rod is obliquely rotatably connected to the vertical pneumatic chucks. The working process of automatically clamping and machining shaft workpieces is as follows:

[0004] The displacement rod moves in the direction of the arrow in Figure 1 description. Outside the machining machine tool, the blank of the shaft workpiece to be machined is clamped by the vertical pneumatic jaws, and then moved to the horizontal pneumatic chuck axially horizontally corresponding to the machine tool chuck. The processed workpiece on the machine tool chuck is clamped by the horizontal pneumatic jaws to achieve the unloading operation. Then, the mutually perpendicular pneumatic jaws rotate to rotate the vertically clamped blank of the workpiece to be machined to the horizontal state and horizontally convey it to the machine tool chuck for clamping. The horizontally clamped processed workpiece is rotated to the vertically clamped state. Then, the displacement rod moves the processed workpiece to the outside of the machine tool. The machine tool chuck rotates for machining, and the pneumatic jaws moved to the outside unload the processed workpiece and then clamp a new blank of the workpiece to be machined again. By repeating the above operations, continuous machining of shaft workpieces can be achieved.

[0005] As shown in the attached Figure 2 description, after the pneumatic jaws horizontally convey the blank of the shaft workpiece to be machined to the machine tool chuck, the machine tool jaws of the machine tool chuck clamp the other end of the workpiece in the direction of the arrow in Figure 3 description. The surface of the unprocessed blank workpiece is usually relatively rough and has poor flatness. Therefore, when the machine tool jaws clamp one side of the workpiece, due to the rough surface, there will be a certain axial deviation (deviation) of the workpiece, as shown in Figure 6As shown by the arrow. During the process of clamping one side of the workpiece by the machine tool chuck, the pneumatic chuck still clamps the other side of the workpiece, avoiding the problem of the workpiece falling during the process of the machine tool chuck and the pneumatic chuck "handing over" the workpiece.

[0006] Due to the influence of the rough surface of the workpiece, there is an axial yaw of the workpiece when the machine tool chuck clamps the workpiece, and the acting force of the yaw will act on the pneumatic chuck, as Figure 7 shown by the arrow in. And the pneumatic chuck is in the state of pneumatic clamping. This relative acting force will cause a gap in the assembly of the pneumatic chuck and the pneumatic chuck for a long time. This gap causes Figure 8 the distance from each pneumatic chuck to the center of the pneumatic chuck shown in to be inconsistent. When clamping the workpiece in the later stage, it causes problems such as axial deflection of the workpiece and insufficient clamping force, thus affecting the machining accuracy of the workpiece and easily causing damage to the pneumatic chuck, increasing the replacement cost. Summary of the Invention

[0007] In view of the above problems, the present application aims to provide a coaxial automatic clamping fixture for shaft workpieces, in which the pneumatic chuck will follow the movement synchronously with the yaw action of the workpiece, thereby solving the problems such as the excessive assembly gap of the pneumatic chuck, the increase of workpiece clamping error, and the easy damage of the pneumatic chuck caused by the relative clamping force of the pneumatic chuck and the yaw force of the workpiece.

[0008] To achieve the above object, the technical solution adopted by the present application is as follows: A coaxial automatic clamping fixture for shaft workpieces, the clamping fixture is of a pneumatic chuck structure, including a pneumatic chuck and pneumatic chucks circumferentially spaced thereon, and the pneumatic chuck is movably coaxially corresponding to the machine tool chuck. Its characteristics are: each of the pneumatic chucks follows the movement synchronously with the direction of the external force under the action of the external force.

[0009] Preferably, each of the pneumatic chucks is of an L-shaped structure, including a driving part connected to the pneumatic chuck and a following part hinged on the driving part, and a limiting mechanism is provided at the hinge between the two.

[0010] Preferably, the limiting mechanism includes an elastic member provided at the hinge of the driving part and the following part to drive the following part to rotate towards the center of the pneumatic chuck, and a limiting block is provided on the following part to be connected to the driving part and keep the two perpendicular to each other.

[0011] Preferably, the acting force of the elastic member is greater than the clamping force of the pneumatic chuck on the shaft workpiece.

[0012] The beneficial effects of this application are as follows: Each pneumatic chuck in this application is set to follow synchronously with the direction of the external force under the action of the external force. Such external force actions include the axial deflection of the workpiece caused by the clamping of the workpiece blank by the machine tool chuck. After the deflection force acts on the pneumatic chuck, the pneumatic chuck will follow synchronously with this deflection action, thereby solving the problems such as the excessive assembly gap of the pneumatic chuck, the increase in workpiece clamping error, and the easy damage of the pneumatic chuck due to the relative clamping force of the current pneumatic chuck and the deflection force of the workpiece. Description of the Drawings

[0013] Figure 1 It is a diagram showing that the pneumatic chuck moves the workpiece to be machined to be axially corresponding to the machine tool chuck.

[0014] Figure 2 For Figure 1 It is a diagram showing that the workpiece to be machined is conveyed into the machine tool chuck on this basis.

[0015] Figure 3 For Figure 2 It is a diagram showing that the machine tool chuck clamps the other end of the workpiece on this basis.

[0016] Figure 4 For Figure 3 It is a diagram showing that the pneumatic chuck releases the clamping of the workpiece on this basis.

[0017] Figure 5 For Figure 4 It is a diagram showing that the whole pneumatic chuck is displaced and separated from the machine tool chuck on this basis.

[0018] Figure 6 It is a diagram showing the axial deflection of the workpiece caused by the rough surface of the workpiece during the clamping process of the machine tool chuck.

[0019] Figure 7 For Figure 6 It is an enlarged diagram of the structure at A in

[0020] Figure 8 It is a diagram showing that the distances from the pneumatic chuck to the center of the pneumatic chuck are unequal after being affected by the axial deflection force of the workpiece.

[0021] Figure 9 For Figure 8 It is a diagram showing the axial skew of the workpiece after clamping on this basis.

[0022] Figure 10 It is a diagram showing the clamping of the workpiece by the clamping fixture of this application.

[0023] Figure 11 For Figure 10 It is a diagram showing that the follower part follows synchronously under the deflection of the workpiece on this basis in this application.

[0024] In the figure: 31 - machine tool chuck; 4 - displacement rod; 5 - shaft workpiece. Detailed implementation manners

[0025] In order to enable those of ordinary skill in the art to better understand the technical solutions of the present application, the technical solutions of the present application will be further described below with reference to the accompanying drawings and embodiments.

[0026] Refer to the Figures 1 to 11 A coaxial automatic clamping fixture for shaft workpieces as shown. This clamping fixture is of a pneumatic chuck structure, including a pneumatic chuck 1 and pneumatic jaws 2 circumferentially spaced thereon. And the pneumatic chuck 1 is movably coaxially corresponding to the machine tool chuck 3. And as Figure 1 shown, two are vertically arranged, and a displacement rod is obliquely rotatably connected to the vertical pneumatic chuck 1. The working process of automatically clamping and machining shaft workpieces is as follows: The displacement rod moves in the direction of the arrow in Figure 1 . Outside the processing machine tool, the blank of the shaft workpiece to be processed is clamped by the vertical pneumatic jaws 2, and then moved to be axially horizontally corresponding to the horizontal pneumatic chuck 1 and the machine tool chuck 3. The processed workpiece on the machine tool chuck 3 is clamped by the horizontal pneumatic jaws 2 to realize the unloading operation. Then, the mutually perpendicular pneumatic jaws 2 rotate to rotate the vertically clamped workpiece blank to be processed to a horizontal state and horizontally convey it into the machine tool chuck 3 for clamping. And the horizontally clamped processed workpiece is rotated to a vertically clamped state. Then, the displacement rod moves the processed workpiece to the outside of the machine tool. The machine tool chuck 3 rotates for processing. And the pneumatic jaws 2 moved to the outside unload the processed workpiece and then clamp a new workpiece blank to be processed again. By circulating the above operations, continuous machining of shaft workpieces can be realized.

[0027] To solve the problems such as the surface roughness of the workpiece to be processed affecting the clamping accuracy of the pneumatic jaws 2 at present. As Figure 10 shown, each of the pneumatic jaws 2 follows the movement synchronously with the direction of the external force under the action of the external force. This external force is, for example, the axial yawing action of the workpiece caused by the clamping of the workpiece blank by the machine tool chuck 3. After this yawing acting force acts on the pneumatic jaws 2, the pneumatic jaws 2 will follow the yawing action synchronously, thereby solving the problems such as the excessive assembly gap of the pneumatic jaws 2, the increase of the workpiece clamping error, and the easy damage of the pneumatic jaws 2 caused by the relative clamping force of the pneumatic jaws 2 and the yawing force of the workpiece.

[0028] Specifically, as Figure 10As shown, each of the pneumatic chucks 2 has an L-shaped structure, including a driving part 21 connected to the pneumatic chuck 1 and a follower part 22 hinged to the driving part 21. After the pneumatic chuck 2 transports the workpiece to be processed into the machine tool chuck 3, during the process of the machine tool chuck 31 contacting and clamping one side of the workpiece, if the workpiece has an axial yaw due to the surface roughness of the workpiece, the yaw force acts on the follower part 22, and the follower part 22 rotates relative to the driving part 21 through the yaw force, achieving the purpose of the follower part 22 following the yaw force and releasing the influence of the yaw force on the follower part 22 (pneumatic chuck 2).

[0029] Since the follower part 22 and the driving part 21 are hinged, in order to ensure that the follower part 22 has a normal clamping effect on the workpiece, a limiting mechanism is provided at the hinge of the follower part 22 and the driving part 21. Through this limiting mechanism, the free rotation of the follower part 22 in the hinge structure is solved, while ensuring the normal clamping force on the workpiece and having a following yaw effect at the same time.

[0030] Specifically, as Figure 10 shown, the limiting mechanism includes an elastic component disposed at the hinge of the driving part 21 and the follower part 22 to drive the follower part 22 to rotate towards the center of the pneumatic chuck 1. This elastic component is preferably a torsion spring (not shown in the figure). By this torsion spring, the follower part 22 is driven towards the center direction of the pneumatic chuck 1, solving the problem that the follower part 22 freely rotates towards the outside and cannot achieve the clamping effect on the workpiece.

[0031] And in order to ensure that the follower part 22 can be closely attached to the circumferential surface of the workpiece for clamping, as Figures 10 - 11 shown, a limiting block 221 is provided on the follower part 22 and is connected to the driving part 21 and keeps the two perpendicular to each other. Under the driving action of the torsion spring on the follower part 22, the limiting block 221 is in contact with the side wall of the driving part 21, ensuring that the follower part 22 and the driving part 21 are in a perpendicular state to each other. Furthermore, the follower part 22 can be closely attached and clamped on the circumferential surface of the workpiece, ensuring the clamping force on the workpiece. When the follower part 22 is subjected to the axial yaw force of the workpiece, it drives the follower part 22 to deflect along with the overcoming of the force of the torsion spring, as Figure 11 shown, thereby releasing the axial yaw force of the workpiece and solving problems such as excessive assembly clearance of the pneumatic chuck 2, increased workpiece clamping error, and easy damage of the pneumatic chuck 2 caused by this axial yaw.

[0032] To prevent the pneumatic clamping force of the pneumatic chuck 1 from overcoming the force of the torsion spring and causing the pneumatic chuck 2 to radially deflect when clamping the workpiece, affecting the flat clamping effect on the workpiece, therefore, the force of the elastic component (torsion spring) is greater than the clamping force of the pneumatic chuck 2 on the shaft workpiece. That is, the pneumatic clamping force is less than the torque of the torsion spring, so that the pneumatic chuck 2 can be flatly clamped when clamping the shaft workpiece.

[0033] The principle of this application is as follows: after the pneumatic chuck 2 conveys the workpiece to be processed into the machine tool chuck 3, during the process of the machine tool chuck 31 contacting and clamping one side of the workpiece, if there is an axial yaw of the workpiece due to the surface roughness of the workpiece, the yaw force acts on the follower part 22, driving the follower part 22 to deflect along with it by overcoming the acting force of the torsion spring, thereby releasing the axial yaw force of the workpiece, and solving problems such as too large assembly clearance of the pneumatic chuck 2, increased workpiece clamping error, and easy damage of the pneumatic chuck 2 caused by the axial yaw.

[0034] The above shows and describes the basic principle, main features and advantages of this application. Without departing from the spirit and scope of this application, this application will also have various changes and improvements, and these changes and improvements all fall within the scope of this application claimed.

Claims

1. A coaxial automatic clamping fixture for shaft workpieces, the clamping fixture is a pneumatic chuck structure, comprising a pneumatic chuck (1) and pneumatic jaws (2) arranged at a circumferential spacing thereon, and the pneumatic chuck (1) is movable to coaxially correspond to a machine tool chuck (3), characterized in that: Under the action of an external force, each of the pneumatic clamping claws (2) moves synchronously with the direction of action of the external force.

2. The coaxial automatic clamping fixture according to claim 1 is characterized in that: Each of the pneumatic clamping jaws (2) is of an L-shaped structure, comprising a driving portion (21) connected to the pneumatic chuck (1), and a follower portion (22) hinged to the driving portion (21), and a limit mechanism is provided at the hinge between the two.

3. The coaxial automatic clamping fixture according to claim 2 is characterized in that: The limiting mechanism comprises an elastic component arranged at the hinge between the driving part (21) and the following part (22) for driving the following part (22) to rotate toward the center of the pneumatic chuck (1), and a limiting block (221) is arranged on the following part (22) and is connected to the driving part (21) and keeps the two parts perpendicular to each other.

4. The coaxial automatic clamping fixture according to claim 3 is characterized in that: The acting force of the elastic component is greater than the clamping force of the pneumatic clamping claw (2) on the shaft workpiece.

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