Positioning clamp for thin-wall bent pipe fitting machining

Abstract

The utility model discloses a positioning fixture for processing thin-wall bent pipe fittings, which belongs to the technical field of lathe fixture design, a positioning base of the positioning fixture is used for mounting a positioning core seat, a positioning support is used for mounting a positioning frame, and vertical kidney-shaped holes are symmetrically arranged on two sides of the positioning frame. A vertical screw in the vertical kidney-shaped hole is installed in a connecting screw hole of the positioning support, two positioning clamping arms are symmetrically installed at the bottom of the positioning frame, the outer diameter of the positioning core body is consistent with the inner diameter of the thin-wall bent pipe, the bottom of the thin-wall bent pipe is supported and limited by the positioning core body, and the top of the thin-wall bent pipe is limited by the two positioning clamping arms in a contact mode. Compared with an existing structure, the positioning clamp drives the positioning core body through threads, the positioning core body and a workpiece are locked through end face stress, clamping force only acts on the clamp matrix and does not directly act on the workpiece, the purpose of eliminating deformation is achieved, and machining precision and concentricity are effectively guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of lathe fixture design technology, and in particular relates to a positioning fixture for machining thin-walled bent pipe parts. Background Technology

[0002] In the field of thin-walled pipe bending, 90-degree thin-walled pipe products with a wall thickness of only 5mm are particularly susceptible to the effects of clamping force, cutting heat and clamping positioning errors during the processing due to their special structure, resulting in a particularly prominent problem of concentricity deviation.

[0003] The existing process has the following technical bottlenecks: First, the traditional clamping method of radially clamping the inner hole with a three-jaw chuck is prone to elastic deformation of 0.05-0.15mm due to the poor rigidity of thin-walled pipes. This cannot meet the accuracy requirement of concentricity ≤0.05mm. Second, although the integrated design of positioning mandrel and threaded fastener attempts to improve stability through over-positioning, irreversible plastic deformation has already occurred on the clamping surface during the roughing stage. During the second clamping, the inaccuracy of the reference surface leads to the superposition of deformation of 0.03-0.12mm. Moreover, the repeated constraints caused by over-positioning further aggravate the deformation.

[0004] Furthermore, existing fixtures generally suffer from insufficient clamping contact area and uneven stress distribution. Even with segmented clamping or improved soft-jaw designs, it remains difficult to balance the critical point between clamping force and deformation suppression. These technical deficiencies significantly limit the application of current processes in the high-precision machining of thin-walled bent pipes. Therefore, designing a novel positioning fixture for machining thin-walled bent pipes to address these technical problems has become a critical challenge in this field. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides a positioning fixture for machining thin-walled bent pipe fittings, solving the problems through the following technical means:

[0006] A positioning fixture for processing thin-walled bent pipe fittings, characterized in that it comprises a mounting base, a positioning base, a positioning support, a positioning frame, and a positioning core seat, wherein: the mounting base is provided with a plurality of mounting holes for connecting the positioning base and the positioning support; the positioning base is an L-shaped structure, the vertical surface of the L-shaped structure is fixed to the mounting base by base screws and base cylindrical pins, and the middle of the horizontal surface of the L-shaped structure is provided with a positioning screw hole and a positioning screw for mounting the positioning core seat; the positioning support is a U-shaped structure, one vertical surface of the U-shaped structure is fixed to the mounting base by support screws and support cylindrical pins, and the other vertical surface of the U-shaped structure is provided with a connecting screw hole for connecting the positioning frame; the two sides of the positioning frame... The positioning frame has symmetrically arranged vertical waist holes, and vertical screws inside the vertical waist holes are installed in the connecting screw holes of the positioning support. Two positioning clamping arms are symmetrically installed at the bottom of the positioning frame. The positioning core seat has a central hole in the middle, and multiple side holes are symmetrically arranged outside the central hole. A spring expansion sleeve connected to the end of the positioning screw is installed inside the central hole. Multiple core screw holes are provided on the positioning core body. The connecting screws in the side holes connect the core screw holes and connect the positioning core seat and the positioning core body into one unit. The outer diameter of the positioning core body is consistent with the inner diameter of the thin-walled bent tube. The bottom of the thin-walled bent tube is supported and limited by the positioning core body and the positioning core seat, and the top of the thin-walled bent tube is limited by the contact of the two positioning clamping arms.

[0007] Preferably, a limit screw is installed at the end of the positioning clamping arm.

[0008] Preferably, the limiting screw and the end face of the thin-walled bent tube in contact with the positioning clamp are both covered with elastic material.

[0009] Preferably, the positioning frame is also symmetrically provided with two transverse waist holes, and transverse screws for connecting the positioning clamping arm are installed in the transverse waist holes.

[0010] Preferably, the outer diameter of the positioning core seat is larger than the outer diameter of the thin-walled bend, and the top of the positioning core seat is provided with a limiting ring groove that contacts the bottom opening of the thin-walled bend.

[0011] The positioning fixture for machining thin-walled bent pipe parts according to this utility model has the following beneficial effects:

[0012] The positioning base of this positioning fixture is used to install the positioning core seat. The positioning core seat and the positioning core body are connected by screws, and the positioning core seat and the positioning base are connected by positioning screws. Rotating the positioning screw in the middle of the positioning base can drive the positioning core body to move up and down. The outer diameter of the positioning core body is the same as the inner diameter of the thin-walled bent tube. The bottom of the thin-walled bent tube is supported and limited by the positioning core body. The positioning support is used to install the positioning frame. The positioning frame has symmetrical vertical waist holes on both sides. The vertical screws inside the vertical waist holes are installed in the connecting screw holes of the positioning support. Two positioning clamping arms are symmetrically installed at the bottom of the positioning frame. The positions of the positioning frame and the positioning clamping arms can be flexibly adjusted. The top of the thin-walled bent tube is limited by the contact of the two positioning clamping arms. This positioning fixture uses a thread to drive the positioning core body and uses the end face force to lock it to the workpiece. The clamping force only acts on the fixture body and not directly on the workpiece, thereby eliminating deformation and effectively ensuring machining accuracy and concentricity. After batch verification, deformation can be controlled within 0.03mm, and concentricity can be controlled within 0.03mm. Attached Figure Description

[0013] To more clearly illustrate the technical solution of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 is a front structural diagram of this utility model;

[0016] Figure 3 is a schematic diagram of the internal structure of this utility model;

[0017] Figure 4 is a schematic diagram of the positioning frame structure of this utility model.

[0018] Among them, 1-mounting base, 101-mounting hole, 2-positioning base, 201-base screw, 202-base cylindrical pin, 203-positioning screw hole, 204-positioning screw, 3-positioning support, 301-support screw, 302-support cylindrical pin, connecting screw hole, 4-positioning frame, 401-vertical waist hole, 402-vertical screw, 403-positioning clamping arm, 404-limiting screw, 405-elastic material, 406-horizontal waist hole, 407-horizontal screw, 5-positioning core seat, 501-center hole, 502-side hole, 503-spring expansion sleeve, 504-positioning core, 505-core screw hole, 506-connecting screw, 507-limiting ring groove, 6-thin-walled bent pipe. Detailed Implementation

[0019] In the description of this utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] As shown in Figures 1 to 4, the positioning fixture for processing thin-walled bent pipes includes a mounting base 1, a positioning base 2, a positioning support 3, a positioning frame 4, and a positioning core seat 5. In the figures, the mounting base 1 is provided with multiple mounting holes 101 for connecting the positioning base 2 and the positioning support 3. The positioning base 2 has an L-shaped structure. The vertical surface of the L-shaped structure is fixed to the mounting base 1 by a base screw 201 and a base cylindrical pin 202. The middle of the horizontal surface of the L-shaped structure is provided with a positioning screw hole 203 and a positioning screw 204 for installing the positioning core seat 5. The positioning support 3 has a U-shaped structure. One vertical surface of the U-shaped structure is fixed to the mounting base 1 by a support screw 301 and a support cylindrical pin 302. The other vertical surface of the U-shaped structure is provided with a connecting screw hole for connecting the positioning frame 4. The positioning frame 4 has symmetrical vertical waist holes 401 on both sides. The vertical screws 402 inside the vertical waist holes 401 are installed in the connecting screw holes of the positioning support 3. Two positioning clamping arms 403 are symmetrically installed at the bottom of the positioning frame 4.

[0022] It should be noted that the positioning frame 4 can also be symmetrically provided with two transverse waist holes 406. Transverse screws 407 for connecting the positioning clamping arms 403 are installed in the transverse waist holes 406. The positions of the positioning frame and the positioning clamping arms can be flexibly adjusted to adapt to parts of different sizes. The top of the thin-walled bent tube 6 can be limited by the contact of the two positioning clamping arms 403.

[0023] In the figure, a central hole 501 is provided in the middle of the positioning core seat 5. Multiple side holes 502 are symmetrically arranged outside the central hole 501. A spring tension sleeve 503 connected to the end of the positioning screw 204 is installed inside the central hole 501. The main clamping force of the spring tension sleeve acts only on the clamping body and does not act directly on the workpiece, thus isolating the main clamping force from directly acting on the workpiece and causing deformation. Multiple core screw holes 505 are provided on the positioning core body 504. The connecting screws 506 in the side holes 502 connect the core screw holes 505 and connect the positioning core seat 5 and the positioning core body 504 into one unit. Rotating the positioning screw 204 can drive the positioning core body 504 to move up and down. The outer diameter of the positioning core body 504 is the same as the inner diameter of the thin-walled bent tube 6. The outer diameter of the positioning core seat 5 is larger than the outer diameter of the thin-walled bent tube 6. A limiting ring groove 507 is provided on the top of the positioning core seat 5 to contact the bottom opening of the thin-walled bent tube 6. In addition, a guide platform is provided at the bottom of the positioning core, and a guide countersunk hole is opened at the top of the positioning core seat 5. The guide platform is movably installed in the countersunk hole.

[0024] It should be noted that the bottom of the thin-walled bent tube 6 is fitted inside the positioning core 504, and the bottom opening of the thin-walled bent tube 6 sits on the limiting ring groove 507. The bottom of the thin-walled bent tube 6 is supported and limited by the positioning core 504 and the limiting ring groove 507. In specific implementation, a limiting screw 404 is installed at the end of the positioning clamping arm 403. An elastic material 405 is attached to the end face of the limiting screw 404 and the positioning clamping arm 403 that contacts the thin-walled bent tube 6. The elastic material 405 can be silicone or rubber.

[0025] In actual operation, the positioning base of this positioning fixture is used to install the positioning core seat. The positioning core seat and the positioning core body are connected to each other by screws, and the positioning core seat and the positioning base are connected by positioning screws. By rotating the positioning screw in the middle of the positioning base, the positioning core body can be moved up and down. The outer diameter of the positioning core body is the same as the inner diameter of the thin-walled bent tube. The bottom of the thin-walled bent tube is supported and limited by the positioning core body. The positioning support is used to install the positioning frame. The positioning frame has symmetrical vertical waist holes on both sides. The vertical screws inside the vertical waist holes are installed in the connecting screw holes of the positioning support. Two positioning clamping arms are symmetrically installed at the bottom of the positioning frame. The positions of the positioning frame and the positioning clamping arms can be flexibly adjusted. The top of the thin-walled bent tube is limited by the contact of the two positioning clamping arms. This positioning fixture uses a threaded drive positioning core, which is then locked to the workpiece by the force applied to its end face. The clamping force is applied only to the fixture body and not directly to the workpiece, thus eliminating deformation and effectively ensuring machining accuracy and concentricity. After batch verification, deformation and concentricity can be controlled to within 0.03mm.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A positioning fixture for machining thin-walled bent pipe fittings, characterized in that, It includes a mounting base (1), a positioning base (2), a positioning support (3), a positioning frame (4), and a positioning core seat (5), wherein: The mounting base (1) is provided with a plurality of mounting holes (101) for connecting the positioning base (2) and the positioning support (3). The positioning base (2) is an L-shaped structure. The vertical surface of the L-shaped structure is fixed to the mounting base (1) by the base screw (201) and the base cylindrical pin (202). The middle of the horizontal surface of the L-shaped structure is provided with a positioning screw hole (203) and a positioning screw (204) for installing the positioning core base (5). The positioning support (3) is a U-shaped structure. One vertical side of the U-shaped structure is fixed to the mounting base (1) by a support screw (301) and a support cylindrical pin (302). The other vertical side of the U-shaped structure is provided with a connecting screw hole for connecting the positioning frame (4). The positioning frame (4) has symmetrical vertical waist holes (401) on both sides. The vertical screws (402) inside the vertical waist holes (401) are installed in the connecting screw holes of the positioning support (3). Two positioning clamping arms (403) are symmetrically installed at the bottom of the positioning frame (4). The positioning core seat (5) has a central hole (501) in the middle. The positioning core seat (5) has multiple side holes (502) symmetrically arranged outside the central hole (501). A spring expansion sleeve (503) connected to the end of the positioning screw (204) is installed inside the central hole (501). Multiple core screw holes (505) are provided on the positioning core body (504). The connecting screw (506) in the side hole (502) connects to the core screw hole (505) and connects the positioning core seat (5) and the positioning core body (504) into one unit. The outer diameter of the positioning core body (504) is consistent with the inner diameter of the thin-walled bent tube (6). The bottom of the thin-walled bend (6) is supported and limited by the positioning core (504) and the positioning core seat (5), and the top of the thin-walled bend (6) is contacted and limited by two positioning clamps (403).

2. The thin-walled elbow work positioning fixture according to claim 1, characterized in that, Limit screws (404) are installed at the end of the positioning arm (403).

3. The thin-walled elbow fitting machining positioning clamp according to claim 2, characterized in that, The limiting screw (404) and the positioning clamp (403) are both attached with elastic material (405) on the end face of the thin-walled bent tube (6).

4. The thin-walled elbow fitting machining positioning clamp according to claim 3, characterized in that, The positioning frame (4) is also symmetrically provided with two transverse waist holes (406), and transverse screws (407) for connecting the positioning clamp arm (403) are installed in the transverse waist holes (406).

5. The thin-walled elbow fitting machining positioning clamp according to claim 4, characterized in that, The outer diameter of the positioning core seat (5) is larger than the outer diameter of the thin-walled bend (6), and the top of the positioning core seat (5) is provided with a limiting ring groove (507) that contacts the bottom opening of the thin-walled bend (6).

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