A double-acting adjustable force zero-clearance internal expansion clamp
Patent Information
- Application Number
- CN202521798151.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2026-09-04
- Estimated Expiration
- 2035-08-22
AI Technical Summary
[0003]箱体孔为阶梯孔，包括顶部孔与底部孔两段不同尺寸直径的孔，常规生产中主要通过通用三爪卡盘方式或定位销轴压板方式装夹固定，由于卡爪行程长及长时间使用磨损，会出现喇叭口形状，造成定位精度下降（径向跳动通常＞0.1mm），及加紧力不均衡，易造成箱体变形（变形量0.05-0.08mm）；定位销式的夹具为保证加工完毕后产品与夹具分离，销和定位孔为间隙配合（H7/g6），导致重复定位精度低（≤0.15mm），有间隙导致精度差，加之磨损后极易造成箱体加工的形状位置公差超标（通常＞0.2mm）
本实用新型设置加长的分段滑块定位加紧轴、可调行程锁紧芯轴及分段的锥套，将箱体装入夹具上，旋转调整螺钉，下压紧锥套先预定位；继续旋转调整螺钉，上压紧锥套同步涨紧顶部孔，实现双作用夹持，箱体定位加紧可靠。分段涨紧结构均匀分布应力，可避免箱体变形，同时可针对箱体孔的底部孔与顶部孔原始加工精度进行补偿。夹紧力通过螺纹机构锁定，可确保加工过程中无松动，有效解决了磨损后的精度下降，加紧力失衡问题。一次装夹，通过五面加工中心/五轴加工中心，即可完成所有工序，减少重复定位带来的累加误差。反向旋转调整螺钉，锥套收缩，箱体即可轻松取下。
Smart Images
Figure CN224713046U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of gearbox housing parts processing technology, specifically relating to a double-acting adjustable force zero-backlash internal expansion clamp for gearbox housing processing. Background Technology
[0002] One of the functions of a gearbox housing is to provide precise support and positioning for components such as gears, shafts, and bearings, ensuring the relative positional accuracy of each component, which is the foundation for ensuring the smoothness and accuracy of gear transmission.
[0003] The housing has stepped holes, consisting of two sections with different diameters: a top hole and a bottom hole. In conventional production, these are typically clamped and fixed using a general-purpose three-jaw chuck or a locating pin clamping plate. However, due to the long travel of the chuck jaws and wear over time, they develop a flared shape, leading to decreased positioning accuracy (radial runout typically >0.1mm) and uneven clamping force, easily causing housing deformation (deformation 0.05-0.08mm). Locating pin type fixtures, to ensure separation of the product from the fixture after machining, use a clearance fit (H7 / g6) between the pin and the locating hole, resulting in low repeatability (≤0.15mm). The clearance leads to poor accuracy, and wear easily causes the shape and position tolerances of the machined housing to exceed the standard (typically >0.2mm). Some internal expansion fixtures are also available on the market, mainly used for small gear parts (diameter <80mm). However, these have low single-acting clamping force (typically <500N) and the force cannot be adjusted, making them unsuitable for machining stepped holes in housings. Utility Model Content
[0004] The purpose of this utility model is to provide a double-acting adjustable force zero-backlash internal expansion clamp to achieve zero-backlash positioning of stepped holes, provide adjustable clamping force to adapt to the processing requirements of different box sizes, reduce the impact of clamp wear on processing accuracy, and extend service life.
[0005] The technical solution adopted by this utility model is as follows: a double-acting adjustable force zero-gap internal expansion clamp, including a circular base, three radial grooves evenly distributed on the upper end of the base, a positioning and clamping shaft in the shape of a frustum formed by three fan-shaped blocks spliced together above the base, a first sealing strip in the joint between the fan-shaped blocks, the lower end of the fan-shaped blocks contacting the base surface, and a matching guide slider corresponding to the radial groove on the center line of each fan-shaped block, the guide slider being elastically pressed towards the center direction by a clamping mechanism, and the lower end of the positioning and clamping shaft... A right-angled circular groove is provided, which respectively contacts the bottom hole end face and the inner hole face of the workpiece. The upper end of the positioning and clamping shaft is connected to an upper shaft part that is cylindrical and composed of fan-shaped columns. A second sealing strip is provided in the joint between the fan-shaped columns. The upper shaft part contacts the inner hole face of the top hole of the workpiece. A through hole is formed in the center of the positioning and clamping shaft. An adjusting screw threaded connection base is provided in the through hole. The through hole is a tapered hole at the positions of the right-angled circular groove and the upper shaft part, which respectively cooperate with the lower clamping tapered sleeve and the upper clamping tapered sleeve installed on the adjusting screw.
[0006] Furthermore, the clamping mechanism includes a spring seat, the main body of which is located behind the guide slider in the radial groove. The upper ends of the main body of the spring seat are provided with wing plates to fix and connect to the base. The main body of the spring seat has a radial through hole, and a pressure rod is provided in the radial through hole. The rear end of the pressure rod is provided with a pressure cap to fix and connect to the main body of the spring seat. A spring is sleeved on the pressure rod. The rear end of the guide slider has a hole corresponding to the radial through hole. The front end of the pressure rod extends into the hole, and the spring abuts against the bottom of the hole.
[0007] Furthermore, both the lower and upper clamping cone sleeves are provided with a lower adjusting ring on their lower sides and an upper adjusting ring on their upper sides.
[0008] Furthermore, a groove is provided on the lower side of the upper shaft, and a limiting ring is sleeved in the groove.
[0009] Furthermore, the upper shaft is composed of six identical sector-shaped columns joined together.
[0010] Furthermore, the upper outer side of the base is provided with axially symmetrically arranged positioning L-plates. The bottom plate of the positioning L-plate is installed on the base. The inner side of the upright plate of one side of the positioning L-plate is provided with a positioning pin, and the upright plate of the other side of the positioning L-plate is threadedly connected with a screw with a handle.
[0011] This utility model has the following beneficial effects: This utility model features an extended segmented slider positioning and clamping shaft, an adjustable stroke locking mandrel, and segmented tapered sleeves. The housing is mounted on the fixture, and rotating the adjusting screw lowers the tapered sleeve for pre-positioning. Continuing to rotate the adjusting screw raises the tapered sleeve, simultaneously tightening the top hole, achieving dual-action clamping and reliable housing positioning and clamping. The segmented tensioning structure evenly distributes stress, preventing housing deformation and compensating for the original machining accuracy of the bottom and top holes in the housing. The clamping force is locked by a threaded mechanism, ensuring no loosening during machining and effectively solving the problems of decreased accuracy and clamping force imbalance after wear. All processes can be completed in a single setup using a five-sided machining center / five-axis machining center, reducing accumulated errors from repeated positioning. Reversing the adjustment screw retracts the tapered sleeve, allowing the housing to be easily removed. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a top view of the present invention; Figure 3 yes Figure 2 LL-direction sectional view; Figure 4 yes Figure 2 MM-direction sectional view; Figure 5 yes Figure 4 NN-direction sectional view; Figure 6 This is a schematic diagram of the clamping mechanism of this utility model; Figure 7 This is a top view of the present invention when it is being clamped; Figure 8 yes Figure 7 Sectional view from the center OO direction.
[0013] In the diagram: 1-base, 2-positioning and clamping shaft, 21-guide slider, 22-right-angled circular groove, 23-upper shaft, 3-first sealing strip, 4-second sealing strip, 5-lower clamping cone sleeve, 6-upper clamping cone sleeve, 7-adjusting screw, 8-spring seat, 9-pressure rod, 91-pressure cover, 10-spring, 11-lower adjusting ring, 12-upper adjusting ring, 13-limiting ring, 14-positioning L-plate, 15-positioning pin, 16-handle, 17-box body. Detailed Implementation
[0014] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed account of a dual-acting adjustable force zero-gap internal expansion clamp of this utility model.
[0015] like Figures 1-5As shown, a dual-acting adjustable force zero-backlash internal expansion clamp includes a circular base 1. Three radial grooves are evenly distributed on the upper end of the base 1. A positioning and clamping shaft 2, formed by three fan-shaped blocks joined together, is located above the base 1. A first sealing strip 3 is installed in the joint between the fan-shaped blocks. The lower end of each fan-shaped block contacts the base surface, and a matching guide slider 21 is provided on the radial groove corresponding to the center line of each fan-shaped block. The guide slider 21 is elastically pressed towards the center direction by a clamping mechanism. A right-angled circular groove 22 is provided at the lower end of the positioning and clamping shaft 2. The right-angled circular groove 22 contacts the bottom hole end face and the inner hole face of the workpiece respectively. The upper end of the positioning and clamping shaft 2 is connected to the upper shaft part 23, which is cylindrical and composed of fan-shaped columns. The joint between the fan-shaped columns is provided with a second sealing strip 4. The upper shaft part 23 contacts the inner hole face of the top hole of the workpiece. A through hole is formed in the center of the positioning and clamping shaft 2. An adjusting screw 7 is threaded to the base 1 in the through hole. The through hole is a tapered hole at the positions of the right-angled circular groove 22 and the upper shaft part 23, which respectively cooperate with the lower clamping tapered sleeve 5 and the upper clamping tapered sleeve 6 installed on the adjusting screw 7.
[0016] Specifically, the clamping mechanism includes a spring seat 8. The main body of the spring seat 8 is located behind the guide slider 21 in the radial groove. Wing plates are provided at both ends of the upper side of the main body of the spring seat. The wing plates are fixedly connected to the base 1 by M10×35 hexagon socket head cap screws. A radial through hole is provided in the main body of the spring seat. A pressure rod 9 is provided in the radial through hole. A pressure cap 91 is provided at the rear end of the pressure rod 9. The pressure cap 91 is fixedly connected to the main body of the spring seat by M8×25 hexagon socket head cap screws. A spring 10 is sleeved on the pressure rod 9. A hole is provided at the rear end of the guide slider 21 corresponding to the radial through hole. The front end of the pressure rod 9 extends into the hole, and the spring 10 abuts against the bottom of the hole.
[0017] In this embodiment, the adjusting screw 7 is an M36X450 hex socket screw, and both the lower clamping cone sleeve 5 and the upper clamping cone sleeve 6 are provided with a lower adjusting ring 11 on their lower sides and an upper adjusting ring 12 on their upper sides.
[0018] The upper shaft part 23 is composed of six identical fan-shaped columns. A groove is provided on the lower side of the upper shaft part 23, and a limiting ring 13 is sleeved in the groove.
[0019] A positioning L-plate 14 is provided on the outer side of the upper end of the base 1, and the bottom plate of the positioning L-plate 14 is installed on the base 1. A positioning pin 15 is provided on the inner side of the upright plate of one side of the positioning L-plate 14, and a screw with a handle 16 is threadedly connected to the upright plate of the positioning L-plate 14 on the other side.
[0020] like Figures 6-8As shown, taking the D02865 housing processing as an example, the bottom hole of the housing 17φ635mm and the top hole of the housing 200.025mm are installed into the fixture. The positioning pin 15 and the handle 16 restrict its rotation. The adjusting screw 7 is rotated to make the lower clamping cone sleeve 5 initially positioned. The torque is controlled by the torque wrench to continue to apply torque, and the upper clamping cone sleeve 6 is simultaneously tightened to the top hole.
[0021] This embodiment's internal expansion clamp uses two sets of upper and lower clamping cone sleeves in conjunction with a double-acting part, which can simultaneously tighten the bottom and top holes of the stepped hole, achieving zero-clearance positioning (clearance < 0.005mm). The positioning and clamping shaft uses thread adjustment (pitch P = 1.5mm), and the clamping force can be precisely controlled by rotating the adjusting screw 7 and the adjusting ring, and the original machining accuracy of the stepped hole is compensated. The clamp has no displacement throughout the entire process, and all feature machining operations on the remaining five sides can be completed in one clamping. During disassembly, rotating the adjusting screw 7 in the opposite direction causes the cone sleeve to retract, and the housing 17 can be quickly removed, saving 40% of the replacement time.
[0022] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.
Claims
1. A double-acting adjustable force zero-backlash internal expansion clamp, characterized in that: The system includes a circular base (1), with three radial grooves evenly distributed on the upper end of the base (1). A positioning and clamping shaft (2) in the shape of a frustum, composed of three fan-shaped blocks, is set above the base (1). A first sealing strip (3) is set in the joint between the fan-shaped blocks. The lower end of the fan-shaped blocks contacts the surface of the base (1), and each fan-shaped block has a matching guide slider (21) corresponding to the radial groove on its center line. The guide slider (21) is elastically pressed towards the center direction by a clamping mechanism. A right-angled circular groove (22) is set at the lower end of the positioning and clamping shaft (2). The right-angled circular groove (22) faces the surface of the base (1). The upper end of the positioning and clamping shaft (2) is connected to the bottom hole end face and inner hole face of the workpiece. It is a cylindrical upper shaft part (23) made of fan-shaped columns. A second sealing strip (4) is set in the joint between the fan-shaped columns. The upper shaft part (23) contacts the inner hole face of the top hole of the workpiece. A through hole is formed in the center of the positioning and clamping shaft (2). An adjusting screw (7) is threaded to the base in the through hole. The through hole is a tapered hole at the position of the right angle circular groove (22) and the upper shaft part (23), which respectively cooperate with the lower clamping tapered sleeve (5) and the upper clamping tapered sleeve (6) installed on the adjusting screw (7).
2. The double-acting adjustable force zero-backlash internal expansion clamp according to claim 1, characterized in that: The clamping mechanism includes a spring seat (8), the main body of the spring seat (8) is set behind the guide slider (21) in the radial groove, the upper two ends of the main body of the spring seat are provided with wing plates to fix and connect the base (1), the main body of the spring seat is provided with a radial through hole, a pressure rod (9) is provided in the radial through hole, the rear end of the pressure rod (9) is provided with a pressure cap (91) to fix and connect the main body of the spring seat, a spring (10) is sleeved on the pressure rod (9), the rear end of the guide slider (21) is provided with a hole corresponding to the radial through hole, the front end of the pressure rod (9) extends into the hole, and the spring (10) abuts against the bottom of the hole.
3. The double-acting adjustable force zero-backlash internal expansion clamp according to claim 1, characterized in that: Both the lower pressing cone sleeve (5) and the upper pressing cone sleeve (6) are provided with a lower adjusting ring (11) on their lower sides and an upper adjusting ring (12) on their upper sides.
4. The double-acting adjustable force zero-backlash internal expansion clamp according to claim 1, characterized in that: The lower side of the upper shaft (23) is provided with a groove, and a limiting ring (13) is sleeved in the groove.
5. The double-acting adjustable force zero-backlash internal expansion clamp according to claim 1, characterized in that: The upper shaft (23) is composed of six identical sector-shaped blocks.
6. The double-acting adjustable force zero-backlash internal expansion clamp according to any one of claims 1 to 5, characterized in that: A positioning L-plate (14) is provided on the outer side of the upper end of the base (1) with axisymmetric arrangement. The bottom plate of the positioning L-plate (14) is installed on the base (1). A positioning pin (15) is provided on the inner side of the upright plate of the positioning L-plate (14) on one side, and a screw with a handle (16) is threadedly connected to the upright plate of the positioning L-plate (14) on the other side.