Spring assembling mechanism and method with adjustable pre-tightening force

Abstract

The invention provides a pre-tightening force adjustable spring assembling mechanism and method, and relates to the technical field of optical machine structural design, the assembling mechanism comprises a second spring, a pin, a shoulder thread sleeve, a bearing and a pin shaft, the axial feeding motion of the second spring is provided by a thread pair composed of a metric thread through hole and the shoulder thread sleeve, and the pin shaft is provided with a pin shaft; rotation of the thread pair and the second spring are decoupled through the bearing, tensioning assembly of the second spring can be completed only by screwing the shoulder thread sleeve, the assembly process of the second spring in the optical machine structure is optimized, and the assembly efficiency is improved; by adjusting the stretching deformation quantity of the second spring, the internal stress state of the optical-mechanical structure is improved, and the problems that a spring assembly mode in an existing optical-mechanical structure is large in operation difficulty and high in risk, and the deformation quantity of the spring cannot be adjusted are solved.

Description

Technical Field

[0001] The invention relates to the technical field of optical-mechanical structure design, and in particular to a spring assembly mechanism and method with adjustable preload force. Background Art

[0002] High-quality optical surfaces are very sensitive to internal stress, and kinematic supports are often used to accurately position and avoid over-constraint. However, in this support structure, the parts are mostly in point and line contact, and there is a lack of conditions for screw connection. Other auxiliary structures are needed to increase the connection stiffness. In addition, in order to ensure the precise alignment of the optical path, the spatial phase of the optical element needs to be adjusted at the micron level, and the transmission gap in its transmission mechanism should be eliminated.

[0003] The spring structure can provide a linearly adjustable preload through its own deformation. The pulling structure formed by it can make the parts in close contact, which can not only effectively ensure the connection stiffness, but also eliminate the transmission gap in the transmission mechanism and improve the stability of the system. It has a wide range of applications in design scenarios such as the kinematic support structure of the reflector, the optical adjustment frame, and the precision translation stage.

[0004] At present, the assembly interface of springs in optical mechanical structures mostly adopts Figure 1 and Figure 2 The form shown in the figure mainly includes a first countersunk through hole 111, two fixed pins 112 and a first spring 113, which are symmetrically arranged between two parts; wherein the hooks at both ends of the first spring 113 are hung on the fixed pin 112 placed in the first countersunk through hole 111; this type of structure mainly has the following problems:

[0005] (1) The operation difficulty and risk of assembling springs of this type of structure are relatively high; first, the fixing pin 112 at one end and the hook of the first spring 113 must be roughly fixed in the first countersunk through hole 111; then the hook at the other end of the first spring 113 must be pulled until the second fixing pin 112 can be simultaneously placed in the hook and the first countersunk through hole 111; during this process, the first spring 113 is in an unstable state where one end is not fixed but stretched; once the pulling end is unhooked from the first spring 113, the fixing pin 112 is easily ejected, seriously threatening other precision devices in the assembly environment; the assembly process usually requires at least two operators to complete together, and the difficulty increases with the increase in the stiffness of the first spring 113;

[0006] (2) This type of structure cannot adjust the deformation of the spring; the optomechanical structure using this assembly form cannot compensate for the performance degradation caused by factors such as processing and assembly deviation and uneven tensioning force by adjusting the stretching length of the first spring 113. Summary of the invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a spring assembly mechanism and method with adjustable preload force.

[0008] A spring assembly mechanism with adjustable preload force comprises: a second spring and a pin, both ends of the second spring are provided with hook rings, a metric threaded through hole is provided on the upper mounting piece, a second countersunk through hole and a mounting groove corresponding to the pin are provided on the lower mounting piece, a shoulder screw sleeve is provided in the metric threaded through hole, a screw sleeve bottom through hole is provided on the shoulder screw sleeve, a bearing is provided inside the shoulder screw sleeve, the assembly mechanism also comprises a pin shaft, the pin shaft passes through the inner ring of the bearing and the screw sleeve bottom through hole in sequence, a mounting hole corresponding to the hook ring is provided at one end of the pin shaft close to the lower mounting piece, the hook ring of the second spring close to one end of the upper mounting piece is installed on the mounting hole, the pin is installed on the mounting groove, and the hook ring of the second spring close to one end of the lower mounting piece is installed on the pin.

[0009] Furthermore, the assembly mechanism also includes an extra flat fine-pitch nut, which is connected to the shoulder threaded sleeve.

[0010] Furthermore, a rectangular groove is formed at the top of the shoulder screw sleeve.

[0011] Furthermore, the bearing is a miniature plane thrust bearing, and the miniature plane thrust bearing is arranged inside the shoulder screw sleeve.

[0012] Furthermore, the pin is a flat-head pin with a hole, and the flat-head pin with a hole passes through the inner ring of the miniature plane thrust bearing and the bottom through hole of the screw sleeve in sequence.

[0013] Furthermore, the assembly mechanism also includes an upper bearing washer, which is arranged on the end surface of the miniature plane thrust bearing away from the lower mounting member.

[0014] Furthermore, the assembly mechanism also includes a lower bearing washer, which is arranged on the end surface of the miniature plane thrust bearing on the side close to the lower mounting member.

[0015] Furthermore, the minor diameter of the metric threaded through hole and the through diameter of the second countersunk through hole are both larger than the envelope outer diameter of the second spring.

[0016] Furthermore, the diameter of the through hole at the bottom of the screw sleeve is larger than the diameter of the pin shaft in the flat-head pin shaft with a hole.

[0017] The present invention also includes a method for assembling a spring with adjustable preload, which is implemented based on a spring assembly mechanism with adjustable preload as described in any of the above items. First, the bearing is installed in a shoulder screw sleeve, the pin is installed in the inner ring of the bearing and the bottom hole of the screw sleeve, and the hook ring of the second spring close to one end of the upper mounting piece is installed on the mounting hole of the pin. Then, the shoulder screw sleeve is rotated to move the assembled bearing, pin, second spring and shoulder screw sleeve along the metric threaded through hole toward the lower mounting piece until the hook ring of the second spring close to one end of the lower mounting piece is installed on the pin in the mounting groove. Finally, the stretching length of the second spring is adjusted by rotating the shoulder screw sleeve to meet the design length requirements.

[0018] The technical solution of the present invention has the following advantages:

[0019] 1. The technical solution provided by the present invention is used as a pulling device in various optical systems to improve the connection stiffness, eliminate the transmission gap, and significantly reduce the operational difficulty of assembling the second spring. It has significant advantages in terms of disassembly and assembly efficiency. The axial feed movement of the second spring is provided by a threaded pair consisting of a metric threaded through hole and a shoulder screw sleeve, and the rotation of the threaded pair is decoupled from the second spring by a bearing. The tensioning and assembly of the second spring can be completed by simply screwing the shoulder screw sleeve. Due to the labor-saving characteristics of the threaded pair, even a second spring with a larger stiffness can be quickly disassembled and assembled; in addition, for structures that require multi-point tightening, the operator is allowed to gradually stretch each second spring to the designed length in sequence, thereby optimizing the assembly process of the second spring in the optomechanical structure and improving the assembly efficiency; by adjusting the deformation amount of the second spring stretching, the internal stress state of the optomechanical structure is improved.

[0020] 2. In the technical solution provided by the present invention, the shoulder screw sleeve can be rotated and stopped at any position along the axial direction of the threaded hole, and can be fixed at any position by cooperating with the special flat fine-pitch nut of the locking device. The operator can use this to stretch the second spring to a specific length and maintain stability at this length, thereby achieving quantitative adjustment of the tensioning force, making the internal stress of the optomechanical structure in the most appropriate state, and improving the working performance of the optical system.

[0021] 3. In the technical solution provided by the present invention, the components of the assembly mechanism are simple in structure, easy to obtain and highly reliable. Most of the parts that make up the spring assembly mechanism are standard parts. The non-standard shoulder screw sleeve is rotationally symmetrical and can be realized using conventional turning technology. The overall production cost of the mechanism is low and the processing efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 Provide a cross-sectional view of the existing spring assembly structure;

[0024] Figure 2 It is a schematic diagram of the existing spring assembly structure;

[0025] Figure 3 It is a cross-sectional view of the overall structure of the present invention;

[0026] Figure 4 It is a cross-sectional view of the upper mounting member of the present invention;

[0027] Figure 5 It is a cross-sectional view of the lower mounting member of the present invention;

[0028] Figure 6 It is a schematic diagram of the structure of the shoulder screw sleeve of the present invention;

[0029] Figure 7 It is a cross-sectional view of the shoulder screw sleeve structure of the present invention;

[0030] Figure 8 It is a schematic structural diagram of the miniature plane thrust bearing, the upper bearing washer and the lower bearing washer of the present invention;

[0031] Fig. 9 It is a cross-sectional view of the structure of the miniature plane thrust bearing, the upper bearing washer and the lower bearing washer of the present invention;

[0032] Fig.10 This is a schematic diagram of the flat-head pin shaft with a hole according to the present invention;

[0033] Fig.11 This is a cross-sectional view of the flat-head pin shaft with a hole according to the present invention.

[0034] Description of reference numerals:

[0035] 111-first countersunk through hole; 112-fixing pin; 113-first spring; 1-shoulder screw sleeve; 11-external thread; 12-rectangular groove; 13-inner cylindrical surface; 14-bottom end face of screw sleeve; 15-bottom through hole of screw sleeve; 2-miniature plane thrust bearing; 21-inner annular surface; 22-outer annular surface; 3-flat head pin with hole; 31-flat head pin end face with hole; 32-flat head pin through hole; 4-extra flat fine-pitch nut; 5-second spring; 6-pin; 7-upper mounting piece; 71-metric threaded through hole; 8-lower mounting piece; 81-second countersunk through hole. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] like Figure 3 to Figure 7A spring assembly mechanism with adjustable preload force shown in the figure comprises: a second spring 5 and a pin 6, both ends of the second spring 5 are provided with hook rings, a metric threaded through hole 71 is provided on the upper mounting piece 7, a second countersunk through hole 81 and a mounting groove corresponding to the pin 6 are provided on the lower mounting piece 8, a shoulder screw sleeve 1 is provided in the metric threaded through hole 71, a screw sleeve bottom through hole 15 is provided on the shoulder screw sleeve 1, a bearing is provided inside the shoulder screw sleeve 1, the assembly mechanism also comprises a pin shaft, the pin shaft passes through the inner ring of the bearing and the screw sleeve bottom through hole 15 in sequence, a mounting hole corresponding to the hook ring is provided on the end of the pin shaft close to the lower mounting piece 8, the hook ring of the second spring 5 close to the upper mounting piece 7 is installed on the mounting hole, the aperture of the mounting hole can be appropriately modified and processed according to the diameter of the second spring 5 used, the pin 6 is installed in the mounting groove, the second spring 5 close to the lower mounting piece 8 The hook ring at one end is installed on the pin 6; the upper mounting piece 7 and the lower mounting piece 8 are two parts to be tightened, the minor diameter of the metric threaded through hole 71 and the diameter of the second countersunk through hole 81 are both larger than the envelope outer diameter of the second spring 5, ensuring that the second spring 5 can pass through the metric threaded through hole 71 and the second countersunk through hole 81; the shoulder screw sleeve 1 is set as the adjustment end of the assembly mechanism, the external thread 11 on the shoulder screw sleeve 1 is matched and connected with the metric threaded through hole 71, the thread length and nominal diameter of the external thread 11 can be determined according to specific usage requirements, the inner wall surface of the shoulder screw sleeve 1 is set as the inner cylindrical surface 13, the inner bottom surface of the shoulder screw sleeve 1 is the bottom end surface 14 of the screw sleeve, the inner cylindrical surface 13 and the bottom end surface 14 of the screw sleeve are used to assemble and position the bearing, the second spring 5 provides tensioning force for the assembly mechanism, and the pin 6 is used to fix the hook ring of the second spring 5 close to one end of the lower mounting piece 8.

[0041] The above-mentioned spring assembly mechanism with adjustable preload force significantly reduces the operational difficulty of assembling the second spring 5, and has significant advantages in terms of disassembly and assembly efficiency. The axial feed movement of the second spring 5 is provided by a threaded pair consisting of a metric threaded through hole 71 and a shoulder screw sleeve 1, and the rotation of the threaded pair is decoupled from the second spring 5 by a bearing. The tensioning and assembly of the second spring 5 can be completed by simply screwing the shoulder screw sleeve 1. Due to the labor-saving characteristics of the threaded pair, even a second spring 5 with a larger stiffness can be quickly disassembled and assembled; in addition, for structures that require multi-point tightening, the operator is allowed to gradually stretch each second spring 5 to the designed length in sequence, thereby optimizing the assembly process of the second spring 5 in the optomechanical structure and improving the assembly efficiency; by adjusting the deformation amount of the second spring 5 stretched, the internal stress state of the optomechanical structure is improved.

[0042] like Figure 3 As shown, in this embodiment, the assembly mechanism also includes an extra flat fine-pitch nut 4, which is connected to the shoulder screw sleeve 1; the extra flat fine-pitch nut 4, the second spring 5 and the pin 6 are all standard parts, and the extra flat fine-pitch nut 4 is used to lock the shoulder screw sleeve 1 to play a role in fixing and preventing loosening. Standard parts make the overall production cost of the mechanism low and the processing efficiency high.

[0043] like Figure 6 As shown, in this embodiment, a rectangular groove 12 is provided at the top of the shoulder screw sleeve 1 to facilitate the operator to use a tool such as a snap ring wrench to screw the shoulder screw sleeve 1 .

[0044] like Figure 3 As shown, in this embodiment, the bearing is a miniature plane thrust bearing 2, and the miniature plane thrust bearing 2 is arranged inside the shoulder screw sleeve 1; the miniature plane thrust bearing 2 is a standard part, which can withstand axial loads in one direction and has a low friction coefficient, which helps to improve work efficiency. The relative torque of the upper and lower end surfaces is unloaded by the balls in the miniature plane thrust bearing 2. The specific bearing model can be selected according to design requirements.

[0045] like Fig.10 and Fig.11 As shown, in this embodiment, the pin is a flat-headed pin 3 with a hole, and the flat-headed pin 3 passes through the inner ring of the miniature plane thrust bearing 2 and the bottom through hole 15 of the screw sleeve in sequence; the flat-headed pin 3 with a hole is a standard component that complies with GB / T882-2008, and the flat-headed pin end face 31 of the flat-headed pin 3 is in contact with the upper end face of the miniature plane thrust bearing 2, and the axial tensioning force of the second spring 5 is transmitted from there to the miniature plane thrust bearing 2, and the diameter of the bottom through hole 15 of the screw sleeve It is larger than the diameter of the pin rod in the flat-headed pin shaft with a hole 3, ensuring that there is a gap between the pin rod in the flat-headed pin shaft with a hole 3 and the through hole 15 at the bottom of the screw sleeve to meet the assembly requirements. The pin rod is technical common sense well known to technical personnel in this field, so it will not be repeated here. The flat-headed pin shaft with a hole is provided with a mounting hole corresponding to the hook ring at one end near the lower mounting member 8, specifically a flat-headed pin shaft through hole 32. The flat-headed pin shaft through hole 32 is used to install the hook ring at one end of the second spring 5 near the upper mounting member 7.

[0046] like Figure 8 and Fig. 9 As shown, in this embodiment, the assembly mechanism also includes an upper bearing washer, which is arranged on the end face of the miniature plane thrust bearing 2 away from the lower mounting member 8; the inner annular surface 21 of the upper bearing washer cooperates with the flat-headed pin shaft 3 with a hole, and the assembly mechanism also includes a lower bearing washer, which is arranged on the end face of the miniature plane thrust bearing 2 close to the lower mounting member 8; the outer annular surface 22 of the lower bearing washer cooperates with the inner cylindrical surface 13 of the shoulder screw sleeve 1, and the arrangement of the upper bearing washer and the lower bearing washer can effectively unload relative rotation.

[0047] like Figure 3 to Figure 11As shown, the present invention also includes a preload-adjustable spring assembly method, which is implemented based on a preload-adjustable spring assembly mechanism described in any one of the above items. First, the bearing is installed in the shoulder screw sleeve 1, the pin is installed in the inner ring of the bearing and the bottom through hole 15 of the screw sleeve, and the hook ring of the second spring 5 close to the upper mounting member 7 is installed on the mounting hole of the pin. Then, the shoulder screw sleeve 1 is rotated to move the assembled bearing, pin, second spring 5 and shoulder screw sleeve 1 along the metric threaded through hole 71 toward the lower mounting member 8, until the hook ring of the second spring 5 close to the lower mounting member 8 is installed on the column pin 6 in the mounting groove, and finally, the stretching length of the second spring 5 is adjusted by rotating the shoulder screw sleeve 1 to meet the design requirement length;

[0048] Specifically, first, the miniature plane thrust bearing 2 is installed into the inner cylindrical surface 13 of the shoulder screw sleeve 1, and the outer ring surface 22 of the lower bearing washer is loosely matched with the inner cylindrical surface 13 of the shoulder screw sleeve 1, until the end face of the lower bearing washer close to the lower mounting part 8 is tightly fitted with the bottom end face 14 of the screw sleeve with the shoulder screw sleeve 1, and the flat-headed hole pin shaft 3 is installed into the inner ring of the miniature plane thrust bearing 2 and the bottom through hole 15 of the screw sleeve, and at the same time, the flat-headed hole pin shaft 3 is also installed into the inner ring surface 21 of the upper bearing washer, until the flat-headed hole pin shaft end face 31 of the flat-headed hole pin shaft 3 is tightly fitted with the end face of the upper bearing washer away from the lower mounting part 8, and then the hook ring of the second spring 5 close to the upper mounting part 7 is installed on the flat-headed hole pin shaft through hole 32 of the flat-headed hole pin shaft 3 , and then take the end of the second spring 5 close to the lower mounting piece 8 as the starting position, make the second spring 5 roughly align with the second countersunk through hole 81, screw the shoulder screw sleeve 1 to move the assembled miniature plane thrust bearing 2, flat head pin shaft 3 with holes, second spring 5 and shoulder screw sleeve 1 along the metric threaded through hole 71 toward the lower mounting piece 8, until the hook ring of the second spring 5 close to the end of the lower mounting piece 8 is installed on the column pin 6 in the mounting groove, finally, adjust the stretching length of the second spring 5 to the design requirement by rotating the shoulder screw sleeve 1, and then continuously debug according to the specific actual situation to make the internal stress of the optical-mechanical structure in an ideal state. After the debugging is completed, screw the extra flat fine-pitch nut 4 onto the external thread 11 of the shoulder screw sleeve 1 to fix the position of the shoulder screw sleeve 1, and the assembly is completed.

[0049] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A spring assembly mechanism with adjustable preload force, comprising: The second spring (5) and the pin (6) are characterized in that hook rings are arranged at both ends of the second spring (5), a metric threaded through hole (71) is provided on the upper mounting member (7), a second countersunk through hole (81) and a mounting groove corresponding to the pin (6) are provided on the lower mounting member (8), a shoulder screw sleeve (1) is arranged in the metric threaded through hole (71), a screw sleeve bottom through hole (15) is provided on the shoulder screw sleeve (1), a bearing is arranged inside the shoulder screw sleeve (1), and the assembly mechanism also includes a pin shaft, which passes through the inner ring of the bearing and the screw sleeve bottom through hole (15) in sequence, and a mounting hole corresponding to the hook ring is provided at one end of the pin shaft close to the lower mounting member (8), the hook ring of the second spring (5) close to one end of the upper mounting member (7) is installed on the mounting hole, the pin (6) is installed on the mounting groove, and the hook ring of the second spring (5) close to one end of the lower mounting member (8) is installed on the pin (6).

2. A spring assembly mechanism with adjustable preload force according to claim 1, characterized in that: The assembly mechanism also includes a special flat fine-pitch nut (4), which is connected to the shoulder screw sleeve (1).

3. A spring assembly mechanism with adjustable preload force according to claim 1, characterized in that: A rectangular groove (12) is formed at the top of the shoulder screw sleeve (1).

4. A spring assembly mechanism with adjustable preload force according to claim 1, characterized in that: The bearing is a miniature plane thrust bearing (2), and the miniature plane thrust bearing (2) is arranged inside the shoulder screw sleeve (1).

5. A spring assembly mechanism with adjustable preload force according to claim 4, characterized in that: The pin shaft is a flat-head pin shaft with a hole (3), and the flat-head pin shaft with a hole (3) passes through the inner ring of the miniature plane thrust bearing (2) and the through hole (15) at the bottom of the screw sleeve in sequence.

6. A spring assembly mechanism with adjustable preload force according to claim 4, characterized in that: The assembly mechanism also includes an upper bearing washer, which is arranged on the end surface of the miniature plane thrust bearing (2) away from the lower mounting member (8).

7. A spring assembly mechanism with adjustable preload force according to claim 4, characterized in that: The assembly mechanism also includes a lower bearing washer, which is arranged on the end surface of the miniature plane thrust bearing (2) on a side close to the lower mounting member (8).

8. The spring assembly mechanism with adjustable preload force according to claim 1, characterized in that: The minor diameter of the metric threaded through hole (71) and the through diameter of the second countersunk through hole (81) are both larger than the envelope outer diameter of the second spring (5).

9. The spring assembly mechanism with adjustable preload force according to claim 5, characterized in that: The diameter of the through hole (15) at the bottom of the screw sleeve is larger than the diameter of the pin shaft in the flat-head pin shaft with a hole (3).

10. A method for assembling a spring with adjustable preload force, the method being implemented based on the spring assembly mechanism with adjustable preload force as claimed in any one of claims 1 to 9, characterized in that: First, the bearing is installed into the shoulder screw sleeve (1), the pin is installed into the inner ring of the bearing and the bottom through hole (15) of the screw sleeve, and the hook ring of the second spring (5) close to the upper mounting member (7) is installed on the mounting hole of the pin. Then, the shoulder screw sleeve (1) is rotated to move the assembled bearing, pin, second spring (5) and shoulder screw sleeve (1) along the metric threaded through hole (71) toward the lower mounting member (8) until the hook ring of the second spring (5) close to the lower mounting member (8) is installed on the column pin (6) in the mounting groove. Finally, the stretched length of the second spring (5) is adjusted to meet the design length by rotating the shoulder screw sleeve (1).

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