Ball screw nut clamp for machining ball screw pair

Abstract

The utility model relates to mechanical processing fixture technical field especially is a kind of ball nut fixture for ball screw pair processing, including base and detachably installed workbench on the top of base, two limit baffle rings are vertically fixed and installed on workbench, and two lower support rings are located between two limit baffle rings, the upper lift sliding installation of workbench has two upper support rings, when two upper support rings drop to with corresponding lower support ring extrusion state, corresponding lower support ring forms complete fixed ring and is wrapped around ball nut, the utility model is closed to form complete fixed ring by upper and lower support ring, and ball nut is fixed by complete circumferential wrapping, this surface contact clamping mode avoids the concentrated stress caused by traditional point contact or local clamping, can evenly distribute the clamping force on the outer cylindrical surface of workpiece, fundamentally eliminates the clamping deformation of workpiece, especially suitable for high-precision grinding process.

Description

Technical Field

[0001] This utility model relates to the field of machining fixture technology, specifically a ball nut fixture for machining ball screw pairs. Background Technology

[0002] As a precision transmission component, the ball screw assembly's core element, the ball nut, directly determines the transmission efficiency, accuracy, and lifespan of the entire assembly. The internal thread raceway of the ball nut typically requires high-precision grinding. During the machining process, ensuring the ball nut is stably, reliably, and without deformation is the primary prerequisite for guaranteeing its machining accuracy.

[0003] In existing technologies, three-jaw chucks or flexible collets are commonly used to clamp ball nuts. While three-jaw chucks offer versatility, their inherent three-point clamping method can easily cause "triangular deformation" in thin-walled ball nuts, and positioning accuracy is difficult to guarantee during repeated clamping. Flexible collets, although providing uniform clamping force, are difficult to precisely control. Insufficient force may cause the workpiece to loosen during machining, while excessive force will also cause elastic deformation of the workpiece, and the recovery of deformation after machining will lead to loss of accuracy. Furthermore, both three-jaw chucks and flexible collets require changing the corresponding jaws or collets when dealing with different types and specifications of ball nuts, making the changeover process cumbersome, time-consuming, and unsuitable for flexible production needs involving multiple varieties and small batches.

[0004] Therefore, there is an urgent need for a ball nut clamp that can achieve rapid and accurate positioning, uniform and stable clamping force, and can be quickly changed to adapt to different workpieces. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a ball nut clamp for machining ball screw pairs, which solves the problems of workpiece deformation, poor repeatability of positioning accuracy, and inconvenience of changing different types of workpieces caused by the existing clamping method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A ball nut fixture for machining ball screw assemblies includes a base and a worktable detachably mounted on top of the base. Two limiting rings and two lower support rings located between the two limiting rings are vertically fixed on the worktable. Two upper support rings are slidably mounted on the upper part of the worktable. When the two upper support rings descend to a state of compression with the corresponding lower support rings, they form a complete fixing ring that wraps around and fixes the ball nut.

[0007] Furthermore, a base is vertically fixedly installed at the bottom of the base, and two symmetrically distributed support legs are vertically fixedly installed at the bottom of the base. Two symmetrically distributed strip-shaped through holes are opened through the base.

[0008] Furthermore, the top of the base is provided with a cavity, and screws extending into the cavity are threaded into all four sides of the base.

[0009] Furthermore, a matching socket is vertically fixed to the bottom of the workbench and snaps into the insertion cavity. Threaded holes are provided around the socket, and the heads of several screws are threaded into the corresponding threaded holes.

[0010] Furthermore, each of the two ports at the top of the two lower support rings is provided with a socket.

[0011] Furthermore, a support seat is vertically fixedly installed on the top of the base, and a lifting electric cylinder is vertically fixedly installed on the top of the support seat.

[0012] Furthermore, the output shaft of the lifting electric cylinder extends through to the top of the worktable and is vertically fixedly mounted with a fixing plate. The two ends of the fixing plate are respectively vertically fixedly connected to two upper support rings.

[0013] Furthermore, each of the two ports at the bottom of the two upper support rings is vertically fixed with a plug, and the two plugs are respectively inserted into the corresponding sockets.

[0014] Beneficial effects of this utility model Compared with the prior art, the advantages of this utility model are: This utility model forms a complete fixing ring by closing the upper and lower support rings, which provides a full-circumferential wrapping fixation for the ball nut. This surface contact clamping method avoids the stress concentration caused by traditional point contact or local clamping, and can evenly distribute the clamping force on the outer surface of the workpiece, fundamentally eliminating the workpiece clamping deformation. It is particularly suitable for high-precision grinding processes. Two limiting rings provide a precise axial positioning reference for the ball nut. The workpiece only needs to be placed on the two lower support rings and its end face contact the limiting rings to complete the axial and radial pre-positioning. The subsequent closing of the upper and lower support rings only serves to lock the workpiece without changing its already determined position, thus ensuring extremely high repeatability in the processing of each product. The core innovation of this invention lies in designing the worktable as a detachable module. Corresponding worktables can be pre-fabricated for different types of ball nuts, and these worktables integrate limiting rings and lower support rings adapted to the workpiece size. When changing products, simply loosen the screws around the base to replace the entire worktable along with its positioning elements. This rapid changeover process significantly reduces equipment downtime and perfectly adapts to the production rhythm of multiple varieties and small batches. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the detachable installation structure of the workbench and base of this utility model; Figure 3 This is a schematic diagram of the installation structure of the lower support ring and the upper support ring of this utility model; Figure 4 This is a schematic diagram of the disassembled structure of the lower support ring and the upper support ring of this utility model.

[0016] In the picture: 1. Base; 11. Support foot; 12. Strip through hole; 2. Base; 21. Insertion cavity; 22. Screw; 3. Workbench; 31. Socket; 32. Threaded hole; 33. Handle; 34. Limiting ring; 35. Lower support ring; 36. Insertion hole; 41. Support base; 42. Lifting electric cylinder; 43. Fixing plate; 44. Upper support ring; 45. Insertion block. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0018] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, and several embodiments of the utility model will be provided. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the utility model more thorough and complete.

[0019] For examples, please refer to Figure 1-4 This utility model provides a technical solution: A ball nut clamp for machining ball screw assemblies includes a base 2 and a worktable 3 detachably mounted on the base 2. A base 1 is vertically fixed to the bottom of the base 2, providing overall support and a mounting reference. Two symmetrically distributed support legs 11 are vertically fixed to the bottom of the base 1, forming stable support in contact with the worktable surface. Two symmetrically distributed strip-shaped through holes 12 are formed on the base 1, allowing bolts to pass through for position adjustment and fastening of the clamp on the machine tool worktable. A cavity 21 is formed at the top of the base 2, serving as a modular interface for precise positioning of the worktable 3. Screws 22, threaded into the cavity 21, are threaded around the base 2. The preload generated by tightening the screws 22 quickly locks the worktable 3. A matching socket 31, fitted into the cavity 21, is vertically fixed to the bottom of the worktable 3. The socket 31 and cavity 21 are precisely fitted together to ensure positioning accuracy. Threaded holes 32 are formed around the socket 31. The heads of several screws 22 are threaded into the corresponding threaded holes 32. Handles 33 are fixedly installed at both ends of the worktable 3. The handles 33 provide the operator with a force point to facilitate the handling and replacement of the module. Two limit rings 34 and two lower support rings 35 located between the two limit rings 34 are vertically fixed on the worktable 3. The limit rings 34 are used to determine the axial machining reference position of the ball nut. The two ports at the top of the two lower support rings 35 are provided with insertion holes 36. The insertion holes 36 serve as a guide structure to ensure the coaxiality of the upper and lower molds when they are closed. Two upper support rings 44 are slidably installed on the upper part of the worktable 3. When the two upper support rings 44 descend to the state of pressing with the corresponding lower support rings 35, they form a complete fixed ring that wraps around and fixes the ball nut. This closed ring structure achieves precise radial positioning and complete circumferential constraint through a small clearance fit with the outer circle of the ball nut. At the same time, the uniform circumferential contact force effectively avoids workpiece deformation caused by local stress concentration.

[0020] A support base 41 is vertically fixedly installed on the top of the base 2. The support base 41 serves as a load-bearing structure to maintain the stability of the lifting mechanism. A lifting electric cylinder 42 is vertically fixedly installed on the top of the support base 41. The lifting electric cylinder 42 provides controllable linear drive to achieve automated clamping. The output shaft of the lifting electric cylinder 42 extends through to the top of the worktable 3 and is vertically fixedly installed with a fixing plate 43. The fixing plate 43 converts the electric cylinder output into dual-sided synchronous movement. The two ends of the fixing plate 43 are vertically fixedly connected to two upper support rings 44 respectively. Insert blocks 45 are vertically fixedly installed at the two ports at the bottom of the two upper support rings 44. The insert blocks 45 are made of hardened steel and form a precision clearance fit with the insertion holes 36. This fit ensures smooth guidance and accurate alignment during mold closing and effectively withstands cutting torque through contact with the hole wall during processing. The two insert blocks 45 are respectively inserted into the corresponding insertion holes 36.

[0021] To further improve the structure, the inner contours of the lower support ring 35 and the upper support ring 44 are formed in one step by wire cutting according to the shape of the ball nut to be processed, ensuring the consistency of cavity precision; the mating surface of the insert block 45 and the insert hole 36 is provided with a guide chamfer to facilitate automatic alignment during mold closing; the positioning end face of the limit stop ring 34 is provided with a wear-resistant coating to improve the service life of the axial positioning surface; the fixed plate 43 and the output shaft of the lifting electric cylinder 42 adopt a double nut anti-loosening structure to ensure long-term operational reliability; the table surface of the worktable 3 is equipped with a chip removal groove to prevent chip accumulation from affecting positioning accuracy.

[0022] To achieve circumferential limiting of the ball nut and prevent it from rotating during processing, an anti-rotation pin (not shown in the figure) is provided on the inner wall of the cavity formed after the lower support ring 35 and the upper support ring 44 are closed. This pin matches the hole or keyway on the ball nut flange. Alternatively, the cross-sectional shape of the cavity matches the outer contour of the ball nut with flange and is a non-circular hole.

[0023] Work process Step 1: Preparation and Installation First, securely mount the entire fixture onto the worktable of the machine tool using bolts through the strip-shaped through hole 12 at the bottom of the base 1. Select a matching worktable 3 module according to the model and specifications of the ball nut to be processed. Align the socket 31 at the bottom of the worktable 3 with and insert it into the cavity 21 at the top of the base 2. Then tighten the screws 22 around the base 2. The heads of the screws 22 will lock into the threaded holes 32 on the side of the socket 31, thereby firmly fixing the worktable 3 to the base 2.

[0024] Step 2: Place the workpiece Activate the lifting cylinder 42, causing its output shaft to retract, which in turn moves the fixed plate 43 and the two connected upper support rings 44 upwards, placing them in the raised and open position. At this time, the operator holds the ball nut and places it steadily into the arc-shaped grooves of the two lower support rings 35 on the worktable 3. Then, gently push along the axial direction of the ball nut, ensuring that its two end faces tightly abut against the two pre-set limit rings 34. This action completes the precise pre-positioning of the workpiece in the axial and radial directions.

[0025] Step 3: Clamp and secure After confirming the workpiece is in place, the lifting cylinder 42 is activated, causing its output shaft to extend downwards. The output shaft pushes the fixed plate 43 downwards, and the two upper support rings 44 connected to both ends of the fixed plate 43 descend synchronously. The inserts 45 at the bottom of the upper support rings 44 are precisely aligned and inserted into the insertion holes 36 at the top of the lower support rings 35. As the lifting cylinder 42 continues to descend, the upper support rings 44 and the lower support rings 35 eventually close tightly, forming a complete annular structure that evenly and firmly wraps around and fixes the ball nut within it.

[0026] Step 4: Perform processing Once it is confirmed that the ball nut has been fully clamped and fixed, the machine tool can be started to perform the predetermined processing steps on the workpiece, such as precision grinding of the internal thread raceway.

[0027] Step 5: Loosen and unload the workpiece After the processing step is completed, the lifting cylinder 42 is raised again, causing the upper support ring 44 to separate from the lower support ring 35. The operator can then remove the processed ball nut from the lower support ring 35, completing one full work cycle.

[0028] Changeover operation: When a different type of ball nut needs to be machined, the operation is very simple. Simply loosen the screws 22 around the base 2, and then remove the entire old worktable 3 module from the base 2 using the handles 33 mounted at both ends of the worktable 3. Then, install the worktable 3 module adapted to the new workpiece model onto the base 2 and tighten the screws 22. This modular design enables rapid changeover between different products.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A ball nut clamp for machining ball screw assemblies, characterized in that: Includes a base (2) and a worktable (3) detachably mounted on the base (2). Two limiting rings (34) and two lower support rings (35) located between the two limiting rings (34) are vertically fixed on the worktable (3). Two upper support rings (44) are slidably mounted on the upper part of the worktable (3). When the two upper support rings (44) descend to the state of squeezing with the corresponding lower support rings (35), they form a complete fixed ring that wraps around the ball nut.

2. The ball nut fixture for machining ball screw assemblies according to claim 1, characterized in that: The base (2) has a base (1) vertically fixed at its bottom. The base (1) has two symmetrically distributed support feet (11) vertically fixed at its bottom. The base (1) has two symmetrically distributed strip-shaped through holes (12).

3. The ball nut fixture for machining ball screw assemblies according to claim 1, characterized in that: The base (2) has a cavity (21) on its top, and screws (22) that extend into the cavity (21) are threaded around the base (2).

4. A ball nut fixture for machining a ball screw assembly according to claim 3, characterized in that: The bottom of the workbench (3) is vertically fixed with a socket (31) that fits into the insertion cavity (21). The socket (31) has threaded holes (32) around its perimeter. The heads of several screws (22) are threaded into the corresponding threaded holes (32). The workbench (3) has handles (33) fixedly installed at both ends.

5. A ball nut fixture for machining ball screw assemblies according to claim 1, characterized in that: Each of the two lower support rings (35) has a jack (36) at one of its two ports at the top.

6. A ball nut fixture for machining ball screw assemblies according to claim 1, characterized in that: A support base (41) is vertically fixedly installed on the top of the base (2), and a lifting electric cylinder (42) is vertically fixedly installed on the top of the support base (41).

7. A ball nut fixture for machining a ball screw assembly according to claim 6, characterized in that: The output shaft of the lifting electric cylinder (42) extends through to the top of the workbench (3) and is vertically fixedly mounted with a fixing plate (43). The two ends of the fixing plate (43) are vertically fixedly connected to two upper support rings (44).

8. A ball nut fixture for machining a ball screw assembly according to claim 5, characterized in that: Two plugs (45) are vertically fixed at the two ports at the bottom of the two upper support rings (44), and the two plugs (45) are respectively inserted into the corresponding plug holes (36).

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