A superimposed double-cam CNC self-centering center frame

Abstract

The present invention relates to the technical field of center frames, and in particular to a superimposed double-cam CNC self-centering center frame, comprising a machine body, the machine body comprising a shell and a machine body cover that are assembled and connected; rotatable side arm assemblies are respectively arranged on both sides of the front end of the shell; a cross arm is arranged in the shell, cams are respectively fixedly arranged on both sides of the cross arm, and the cross arm is driven by a driving assembly and performs linear reciprocating motion; the driving assembly is built into the interior of the cross arm; the side arm assembly comprises a side arm, and rollers A and rollers B are arranged at the rear end of the side arm; rotatable support bearings are arranged at the front ends of the cross arm and the side arm; a double-layer curved surface is arranged on the cam, and the double-layer curved surface comprises a cam curved surface A and a cam curved surface B; the cam curved surface A is located on one side of the machine body cover; and at the same time, a rotary assembly is also included, and the rotary assembly is used to ensure that roller A rolls with cam curved surface A, and roller B rolls with cam curved surface B. In this way, the compactness of the external dimensions is ensured, and the clamping range of the workpiece is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of center frames, in particular to a superimposed double-cam numerically controlled self-centering center frame. Background Art

[0002] In recent years, with the continuous improvement of the requirements for the machining accuracy of mechanical parts, the center frame industry as a machine tool auxiliary equipment has developed rapidly, especially for the machining of slender shafts and crankshafts. The CNC self-centering center frames on the market are generally lever-single cam mechanisms. Due to the external spatial dimensions of the center frame, their clamping range is not large. Therefore, for machine tools that need to be equipped with a center frame, when the machine tool itself has a large processing range and a compact processing area, there are few center frames that can provide a large clamping range and a small external dimension to match such machine tools. Most of the practices are to install several CNC self-centering center frames with different clamping ranges on a machine tool, and use the series connection of the clamping sizes to meet the machine tool's processing needs within the entire processing range. This undoubtedly brings great difficulties to the design, development, production, and sales of machine tools, and will also impose a greater burden on users' purchasing power.

[0003] For the lever-single cam mechanism commonly used in the market, its principle is realized by a precision-machined cam mechanism, such as Figure 1 As shown, it mainly includes hydraulic cylinder 1A, cam 2A, side wall 3A and cross arm 4A. The front end of side wall 3A is equipped with a rotatable support bearing, and hydraulic cylinder 1A is external. During the process, hydraulic cylinder 1A pushes cam 2A, and rollers are installed at the rear end of side wall 3A. The rollers roll on the action surface on cam 2A, and cam 2A drives cross arm 4A to move. During the return process, a return plate is required to ensure that side wall 3A can rotate open when cam 2A returns. Among them, there is a certain geometric relationship between the curve length of the action surface on cam 2A and the clamping diameter range. The longer the curve length, the larger the clamping range; the shorter the curve length, the smaller the clamping range. The length of the curve of cam 2A also largely determines the length and width of the center frame. This is also the fundamental reason why the current center frame products at home and abroad cannot achieve a large clamping range and ultra-compact dimensions. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects and shortcomings in the prior art. To this end, the present invention provides a superimposed double-cam CNC self-centering center frame, which can achieve compact dimensions and expand the clamping diameter range.

[0005] In order to achieve the above-mentioned object, the present invention provides a superimposed double-cam CNC self-centering center frame, comprising a machine body, the machine body comprising a shell and a machine body cover which are assembled and connected; rotatable side arm assemblies are respectively arranged on both sides of the front end of the shell; a cross arm is arranged in the shell, cams are respectively fixedly arranged on both sides of the cross arm, and the cross arm is driven by a driving assembly and performs linear reciprocating motion; the driving assembly is built into the interior of the cross arm; the side arm assembly comprises a side arm, and a roller A and a roller B are arranged at the rear end of the side arm; the front ends of the cross arm and the side arm are both provided with rotatable support bearings;

[0006] The cam is provided with a double-layer curved surface, and the double-layer curved surface includes a cam curved surface A and a cam curved surface B; the cam curved surface A is located on one side of the body cover;

[0007] The center frame also includes a rotating assembly, which is used to ensure that the roller A rolls with the cam surface A, and the roller B rolls with the cam surface B; the side arm assembly is configured so that when the cam surface A and the cam surface B push the side arm assembly in turn, the clamping diameter of the center frame gradually decreases.

[0008] Furthermore, the drive assembly includes an end cover and a push rod; one end of the push rod is threadedly connected to the end cover, and the other end is provided with a piston; the piston is dynamically sealed with a pressure chamber, and the pressure chamber is arranged in the cross arm; one end of the pressure chamber is open, and the other end is closed; the open end of the pressure chamber is sealed with a sealing cover; the push rod is dynamically sealed with the sealing cover; the piston separates the pressure chamber into a release chamber and a clamping chamber, and the release chamber is located between the piston and the sealing cover; the push rod is provided with an oil port A and an oil port B, the oil port A is communicated with the clamping chamber, and the oil port B is communicated with the release chamber.

[0009] Furthermore, the rotating assembly includes a rotating shaft, a spiral spring and a top cover; the side arm rotates through the rotating shaft, and the rotating shaft is fixed in the shell; a cavity with an open end is provided between the side arm and the rotating shaft, the spiral spring is located in the cavity, one end of the spiral spring is fixed to the rotating shaft, and the other end is fixed to the side arm; a top cover is fixed to the open end of the cavity.

[0010] Furthermore, the center frame also includes a guide assembly, and the guide assembly includes a pin shaft and a slide groove that slide with each other, the pin shaft is arranged on the side arm, and the slide groove is arranged on the body cover.

[0011] Compared with the prior art, the beneficial effects of the present invention are: by arranging a double-layer cam surface on the cam, the clamping radius range is expanded compared with the same existing product; by embedding the drive assembly inside the cross arm, the external space is saved, and the external dimensions are compact, and the external dimensions are significantly smaller than the same existing product; at the same time, the return plate used in the prior art is omitted, so that the structure is simple and the cost of using raw materials is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The schematic diagram of the prior art.

[0013] Figure 2 It is a structural schematic diagram of the present invention.

[0014] Figure 3 for Figure 2 Schematic diagram of the internal structure.

[0015] Figure 4 It is a schematic diagram of the guide component in the present invention.

[0016] Figure 5 It is a schematic diagram of the return component in the present invention.

[0017] Figure 6 for Figure 5 PP cross-sectional view.

[0018] Figure 7 It is a schematic diagram of the driving component in the present invention.

[0019] Wherein: 1. Shell; 2. Side arm assembly; 3. Support bearing; 4. Cross arm; 5. Body cover; 6. Drive assembly; 7. Cam; 21. Roller A; 22. Side arm; 23. Roller B; 24. Pin; 25. Volute spring; 26. Top cover; 51. Slide groove; 61. End cover; 62. Push rod; 63. Sealing cover; 64. Piston; 65. Pressure chamber; 66. Oil port A; 67. Oil port B; 71. Cam surface A; 72. Cam surface B; 651. Release chamber; 652. Clamp chamber. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0022] Example

[0023] See also Figure 1 and Figure 7 The present invention provides a superimposed double-cam CNC self-centering center frame, including a machine body, which includes a housing 1 and a housing cover 5 that are assembled and connected; rotatable side arm assemblies 2 are respectively arranged on both sides of the front end of the housing 1; a cross arm 4 is arranged in the housing 1, and cams 7 are respectively fixedly arranged on both sides of the cross arm 4, and the cross arm 4 is driven by a driving assembly 6 and performs linear reciprocating motion; the driving assembly 6 is built into the interior of the cross arm 4; the side arm assembly 2 includes a side arm 22, and a roller A21 and a roller B23 are arranged at the rear end of the side arm 22; The front ends of the cross arm 4 and the side arm 22 are both provided with rotatable support bearings 3; a double-layer curved surface is provided on the cam 7, and the double-layer curved surface includes a cam curved surface A71 and a cam curved surface B72; the cam curved surface A71 is located on one side of the body cover 5; at the same time, it also includes a rotating component, and the rotating component is used to ensure that the roller A21 rolls with the cam curved surface A71, and the roller B23 rolls with the cam curved surface B72; when the cam curved surface A71 and the cam curved surface B72 push the side arm component 2 in turn, the clamping diameter of the present invention gradually becomes smaller.

[0024] As an embodiment of the present invention, Figure 7 As shown, the drive assembly 6 includes an end cover 61 and a push rod 62; wherein, one end of the push rod 62 is threadedly connected to the end cover 61, and the other end is provided with a piston 64; the piston 64 is dynamically sealed with a pressure chamber 65, and the pressure chamber 65 is arranged in the cross arm 4; one end of the pressure chamber 65 is open, and the other end is closed; the open end of the pressure chamber 65 is sealed with a sealing cover 63; the push rod 62 is dynamically sealed with the sealing cover 63; the piston 64 divides the pressure chamber 65 into a release chamber 651 and a clamping chamber 652, and the release chamber 651 is located between the piston 64 and the sealing cover 63; an oil port A66 and an oil port B67 are provided in the push rod 62, wherein the oil port A66 is communicated with the clamping chamber 652, and the oil port B67 is communicated with the release chamber 651.

[0025] As an embodiment of the present invention, Figure 5 and Figure 6As shown, the rotary assembly includes a rotating shaft, a spiral spring 25 and a top cover 26; the side arm 22 rotates through the rotating shaft, and the rotating shaft is fixed in the housing 1; a cavity with an open end is provided between the side arm 22 and the rotating shaft, and the spiral spring 25 is located in the cavity, one end of the spiral spring 25 is fixed on the rotating shaft, and the other end is fixed on the side arm 22; a top cover 26 is fixed to the open end of the cavity.

[0026] As an embodiment of the present invention, Figure 4 As shown, the center frame further includes a guide assembly, which includes a pin shaft 24 and a slide groove 51 that slide with each other, the pin shaft 24 is arranged on the side arm 22, and the slide groove 51 is arranged on the body cover 5. In this way, the accuracy of the clamping movement process is further guaranteed.

[0027] After the present invention is installed as a finished product, the roller A21 is in contact with the cam surface A71, and the spiral spring 25 is in a relaxed state or a compressed state.

[0028] During the use of the present invention, hydraulic oil circulates to the clamping chamber 652 and the releasing chamber 651 through the oil port A66 and the oil port B67 respectively. Initially, the roller A21 contacts the cam surface A71, and the roller B23 moves away from the cam 7. The cross arm 4 moves forward linearly relative to the piston 64. The cam surface A71 pushes the roller A21 and drives the side wall 22 to rotate. At this time, the spiral spring 25 is compressed, and the elastic force of the spiral spring 25 makes the roller A21 and the cam surface A71 roll together, and the clamping radius gradually decreases at this time; when the roller A21 leaves the cam 7, the roller B23 contacts the cam surface B72, and under the action of the spiral spring 25, the roller B23 and the cam surface B72 roll together until the minimum value of the clamping diameter is reached. When clamping stops and needs to be released, the cross arm 4 moves linearly backward relative to the piston 64, and under the action of the spiral spring 25, the side wall 22 can be released, and the roller A21 rolls with the cam surface A71, and the roller B23 rolls with the cam surface B72.

[0029] Specifically, the same product with a maximum clamping diameter within the range of 520 mm ± 10 mm is selected for comparison with the present invention, see Table 1.

[0030] Table 1 Comparison between the existing products and the present invention

[0031] Region / Model Clamping range(mm) Length A(mm) Width B(mm) German brand K6.1 215--510 815.5 680 Indian brand FRU-B7 200--530 1001 710 Domestic brand PK11500X150U 150--500 928 720 The present invention 100--520 697 678

[0032] In Table 1, length A is the distance between the center of the clamping minimum diameter circle and the rear end of the center frame. The prior art all uses external hydraulic cylinders, and the corresponding distances are to the rear end of the hydraulic cylinders. The present invention uses the distance to the rear end of the end cover 61. Width B is the distance between the two ends of the shell 1 in the direction perpendicular to the length.

[0033] It can be seen from Table 1 that in terms of length A and width B, the existing center frames at home and abroad are larger than those of the present invention; at the same time, in terms of the workpiece clamping range, the present invention has a larger clamping range than the existing products of the same type, which meets the use requirements and saves the use cost.

[0034] The present invention may be summarized in other specific forms that do not violate the spirit or main features of the present invention. Therefore, no matter from which point of view, the above embodiments of the present invention can only be regarded as an explanation of the present invention and cannot limit the present invention. The claims indicate the scope of the present invention, while the above description does not indicate the scope of the present invention. Therefore, any changes within the meaning and scope equivalent to the claims of the present invention should be considered to be included in the scope of the claims of the present invention.

Claims

1. A superimposed double cam CNC self-centering center frame, characterized in that: The machine body comprises a housing (1) and a housing cover (5) which are assembled and connected; rotatable side arm assemblies (2) are respectively arranged on both sides of the front end of the housing (1); a cross arm (4) is arranged inside the housing (1), cams (7) are respectively fixedly arranged on both sides of the cross arm (4), and the cross arm (4) is driven by a driving assembly (6) to perform linear reciprocating motion; the driving assembly (6) is built into the cross arm (4); the side arm assembly (2) comprises a side arm (22), and a roller A (21) and a roller B (23) are arranged at the rear end of the side arm (22); and rotatable support bearings (3) are arranged at the front ends of the cross arm (4) and the side arm (22); The cam (7) is provided with a double-layer curved surface, the double-layer curved surface comprising a cam curved surface A (71) and a cam curved surface B (72); the cam curved surface A (71) is located on one side of the machine body cover (5); The center frame also includes a rotating assembly, which is used to ensure that the roller A (21) rolls with the cam surface A (71) and the roller B (23) rolls with the cam surface B (72); the side arm assembly (2) is configured such that when the cam surface A (71) and the cam surface B (72) push the side arm assembly (2) in turn, the clamping diameter of the center frame gradually decreases.

2. The center frame according to claim 1, characterized in that: The driving assembly (6) comprises an end cover (61) and a push rod (62); one end of the push rod (62) is threadedly connected to the end cover (61), and the other end is provided with a piston (64); the piston (64) is dynamically sealed with a pressure chamber (65), and the pressure chamber (65) is provided in the cross arm (4); one end of the pressure chamber (65) is open and the other end is closed; the open end of the pressure chamber (65) is sealed with a sealing cover (63); the push rod (62) ) is dynamically sealed with the sealing cover (63); the piston (64) divides the pressure chamber (65) into a release chamber (651) and a clamping chamber (652), and the release chamber (651) is located between the piston (64) and the sealing cover (63); an oil port A (66) and an oil port B (67) are provided in the push rod (62), the oil port A (66) is communicated with the clamping chamber (652), and the oil port B (67) is communicated with the release chamber (651).

3. The center frame according to claim 1, characterized in that: The rotary assembly comprises a rotating shaft, a spiral spring (25) and a top cover (26); the side arm (22) rotates via the rotating shaft, and the rotating shaft is fixed in the housing (1); a cavity with an open end is provided between the side arm (22) and the rotating shaft, the spiral spring (25) is located in the cavity, one end of the spiral spring (25) is fixed to the rotating shaft, and the other end is fixed to the side arm (22); a top cover (26) is fixed to the open end of the cavity.

4. The center frame according to any one of claims 1 to 3, characterized in that: The center frame also includes a guide assembly, which includes a pin shaft (24) and a slide groove (51) that slide with each other, the pin shaft (24) is arranged on the side arm (22), and the slide groove (51) is arranged on the body cover (5).

Images