Automatic clutch device for screw transmission end

Abstract

The present invention provides an automatic clutch device for a screw transmission end, comprising a screw (10), a nut (20), a cam clutch mechanism and a preload spring mechanism; the screw (10) is an integrally formed structure, comprising a threaded section (11) and an optical axis section (12) whose central axes are colinear; the optical axis section (12) has a longitudinal cross-section in a "convex" shape and the end of its large diameter section is connected to the threaded section (11); the cam clutch mechanism is coaxially arranged on a side of the nut (20) away from the threaded section (11), comprising a support sleeve (31), a support pin (32), an elliptical cam (33) and a limit pin (34); the preload spring mechanism is coaxially arranged on a side of the cam clutch mechanism away from the nut (20). The device can not only realize overload protection during the transmission process of the screw and nut, but also ensure that the screw and nut can be stably engaged again after the idle stroke protection is performed.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical transmission, and in particular to an automatic clutch device for a screw transmission end. Background Art

[0002] Screw transmission converts rotary motion into linear motion. It has low friction loss, high transmission efficiency and high precision. Compared with hydraulic transmission, it is simple to operate, low cost and low energy consumption. At present, screw transmission is widely used in mechanical structures for lifting operations and horizontal transmission.

[0003] During lifting operations, the nut rotates to drive the screw in reciprocating motion, thereby lifting and releasing the load. However, when the screw reaches its limit, it is prone to overloading the power equipment. Currently, idle stroke protection is often used to prevent equipment overload during lifting. When the screw reaches its top position and is protected by idle stroke, the nut reverses and returns to its original position. The screw can rely on load pressure or the load and the screw's own counterweight to re-engage with the nut and return to its original position, completing the descent process. However, when the screw reaches its lowest position and is protected by idle stroke, the load pressure or counterweight makes it difficult for the screw to re-engage with the nut (i.e., the nut continues to idle), causing the entire lifting mechanism to jam and affecting the continuity of the operation. For horizontal transmission, when the screw uses idle stroke protection to prevent overload, the screw also has difficulty re-engaging with the nut, and cannot effectively ensure the smooth operation of the entire mechanism. Summary of the Invention

[0004] In response to the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an automatic clutch device at the end of a screw transmission, which can not only realize overload protection at the extreme position during the transmission process of the screw and nut, but also ensure that the screw and the nut can be stably engaged again after the empty stroke protection, thereby ensuring the smooth operation of the mechanism and avoiding jamming of the entire mechanism.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The cam clutch mechanism is coaxially arranged on the side of the nut away from the threaded section, and comprises a support sleeve, a support pin, an elliptical cam and a limit pin, the support sleeve is arranged at the shoulder of the convex structure of the optical axis section and is sleeved on the outer wall of the small diameter section of the optical axis section, and multiple support pins are evenly arranged on the outside of the support sleeve and around its axis, and the outer walls of the support pins are respectively rotated to sleeve the elliptical cams, and the limit pins are fixedly arranged on the outer wall of the support sleeve corresponding to the elliptical cam, and are located obliquely below the support pin; the pre-tightening spring mechanism is coaxially arranged on the side of the cam clutch mechanism away from the nut.

[0007] For further optimization, the elliptical cam is eccentrically sleeved on the outer wall of the support pin shaft, and the center of the elliptical cam has a downward eccentric distance δ relative to the center of the support pin shaft in the direction of the long axis of the elliptical cam.

[0008] Preferably, the eccentricity δ is not greater than the radius of the support pin.

[0009] For further optimization, the side wall of the elliptical cam away from the support sleeve is limited by a retaining spring to prevent the elliptical cam from sliding along the axis of the support pin shaft.

[0010] For further optimization, the angle between the connecting line of the support pin and the limit pin and the vertical line is a and a Not less than 45°.

[0011] Preferably, the number of the supporting pins is 3 to 8, and the number of the corresponding elliptical cams and limiting pins is 3 to 8.

[0012] For further optimization, the elliptical cam and the limit pin are arranged in a circular array around the center of the support sleeve (that is, the eccentrically arranged elliptical cams are oriented in the same direction and the limit pins are located below the same rotation side of the elliptical cams).

[0013] For further optimization, the preload spring mechanism includes a lower spring seat, an upper spring seat and a compression spring; the lower spring seat is located on the side of the support sleeve away from the nut and its inner wall is slidably connected to the outer wall of the small diameter section of the optical axis segment, the upper spring seat is fixedly connected to the end of the small diameter section of the optical axis segment (that is, the end of the optical axis segment away from the threaded section) and the upper spring seat and the lower spring seat are connected by a compression spring, and the compression spring is located on the outer ring of the optical axis segment.

[0014] The present invention has the following technical effects:

[0015] The present application utilizes the friction of the idling nut to drive the elliptical cam to rotate by cooperating with the support sleeve, support pin, elliptical cam, limit pin and preload spring mechanism, so that the nut and the threaded section of the screw are re-engaged by the elastic pressure of the preload spring mechanism, thereby realizing overload protection of the screw and nut transmission and automatic and stable switching into meshing drive without the need for external force intervention, effectively realizing the continuity and smoothness of the mechanism transmission; the preload spring mechanism eliminates the pressure damage to the mechanism or overload of the power device during the meshing process of the screw thread section and the nut, thereby effectively protecting the mechanism and increasing the service life of the mechanism. At the same time, the present application effectively distributes the pressure generated by the spring by setting multiple sets of elliptical cams, avoiding pressure loss on the elliptical cam or nut, while ensuring that the nut moves along its axial direction and avoiding the problem of tooth jamming or tooth grinding between the nut and the threaded section; in addition, the eccentric structure of the elliptical cam ensures stable contact with the nut during the reversal process, thereby ensuring stable pressure transmission.

[0016] The device of the present application has a compact structure and low cost, and can be effectively applied to the idle stroke protection and automatic resetting engagement of the screw and nut during lifting operations or horizontal transmission, etc. It has a wide range of applications and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the automatic clutch device in an embodiment of the present invention.

[0018] Figure 2 for Figure 1 AA section view.

[0019] Figure 3 Schematic diagram of the structure of another state of the automatic clutch device in an embodiment of the present invention.

[0020] Among them, 10, lead screw; 11, threaded section; 12, optical axis section; 20, nut; 31, support sleeve; 32, support pin; 320, retaining spring; 33, elliptical cam; 34, limit pin; 41, lower spring seat; 42, upper spring seat; 43, compression spring. Implementation Method

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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 making creative efforts are within the scope of protection of the present invention. Example

[0022] like Figures 1 to 3The figure shows an automatic clutch device for a screw transmission end, characterized in that it includes a screw 10, a nut 20, a cam clutch mechanism and a preload spring mechanism; the screw 10 is an integrally formed structure, including a threaded section 11 and an optical axis section 12 with a central axis colinear, the longitudinal cross-section of the optical axis section 12 is a "convex" structure and the end of its large diameter section is connected to the threaded section 11 (that is, the small diameter section of the optical axis section 12 is located at the end of the large diameter section away from the threaded section 11, as shown in FIG. Figure 1 、 Figure 3 As shown); the nut 20 is coaxially arranged on the outer wall of the screw 10 (ie, the nut 20 is colinear with the central axis of the screw 10) and its inner hole wall can be threadedly connected with the threaded segment 11 (as shown); Figure 1 、 Figure 3 As shown: the large diameter section of the optical axis section 12 of the screw 10 can slide freely in the inner hole of the nut 20).

[0023] The cam clutch mechanism is coaxially arranged on the side of the nut 20 away from the threaded section 11 (ie, the cam clutch mechanism is coaxial with the central axis of the nut 20 and the cam clutch mechanism is located on the upper side of the nut 20, as shown in FIG. Figure 1 、 Figure 3 As shown in FIG, the support sleeve 31 includes a support pin 32, an elliptical cam 33, and a limit pin 34. The support sleeve 31 is arranged at the shoulder of the "convex" structure of the optical axis segment 12 and is sleeved on the outer wall of the small diameter section of the optical axis segment 12 (that is, the inner hole of the support sleeve 31 and the outer wall of the small diameter section of the optical axis segment 12 are interference-connected); a plurality of support pins 32 are evenly arranged outside the support sleeve 31 and around its axis. The number of support pins 32 is 3 to 8 (the number of support pins 32 in this embodiment is 6, as shown in FIG. Figure 2 As shown); the outer wall of the support pin 31 rotates and sleeves the elliptical cam 33, as shown Figure 1 、 Figure 3 As shown: the elliptical cam 33 is eccentrically sleeved on the outer wall of the support pin 32 (that is, the central axis of the elliptical cam 33 is not in a straight line with the central axis of the support pin 32, and the number of the elliptical cams 33 in this embodiment is also 6), and the center of the elliptical cam 33 has a downward eccentric distance δ in the long axis direction of the elliptical cam 33 relative to the center of the support pin 32, and the eccentric distance δ is not greater than the radius of the support pin 32; the side wall of the elliptical cam 33 away from the support sleeve 31 is limited by the retaining spring 320 to prevent the elliptical cam 33 from sliding along the axis direction of the support pin 32. The limiting pin 34 is fixedly arranged on the outer wall of the support sleeve 31 corresponding to the elliptical cam 33 (that is, the number of the limiting pins 34 is 6 and the central axis of the limiting pin 34 is parallel to the central axis of the support pin 32), and is located on the oblique lower side of the support pin 32, and the diameter of the limiting pin 34 is smaller than the diameter of the support pin 32; as shown Figure 1 As shown: the angle between the connecting line of the support pin 32 and the limiting pin 34 and the vertical line is a and a Not less than 45° (in this embodimenta is 60°). Figure 2 As shown, the elliptical cam 33 and the limiting pin 34 are arranged in a circular array around the center of the support sleeve 31 (that is, the eccentrically arranged elliptical cam 33 is oriented in the same direction and the limiting pin 34 is located below the same rotation side of the elliptical cam 33).

[0024] The preload spring mechanism is coaxially arranged on the side of the cam clutch mechanism away from the nut 20 (i.e. Figure 1 、 Figure 3 The upper side is shown); the preload spring mechanism includes a lower spring seat 41, an upper spring seat 42 and a compression spring 43; the lower spring seat 41 is located on the side of the support sleeve 31 away from the nut 20 and its inner wall is slidably connected to the outer wall of the small diameter section of the optical axis segment 12, the upper spring seat 42 is fixedly connected to the end of the small diameter section of the optical axis segment 12 (that is, the end of the optical axis segment 12 away from the threaded section 11) and the upper spring seat 42 and the lower spring seat 41 are connected by a compression spring 43, and the compression spring 43 is located on the outer ring of the optical axis segment 12; when the nut 20 is in idling operation: the bottom surface of the lower spring seat 41 coincides with the end surface of the support sleeve 31.

[0025] Working principle:

[0026] like Figure 1 As shown: when the nut 20 rotates on the outer wall of the screw 10 until the threaded section 11 of the screw 10 is separated from the nut 20 and the large diameter section of the optical axis section 12 of the screw 10 is completely aligned with the nut 20, the nut 20 idles and the screw 10 no longer moves downward, and the entire mechanism completes the overload idle stroke protection; at this time, the end face of the nut 20 contacts the bottom surface of the support sleeve 31, the end face of the support sleeve 31 contacts the bottom surface of the lower spring seat 41, and the elliptical cam 33 is in the automatic state.

[0027] When it is necessary to re-engage the threaded section 11 of the lead screw 10 with the nut 20 and complete the rotation of the nut 20 to drive the lead screw 10 to move, the nut 20 is reversed. Due to the contact between the bottom surface of the nut 20 and the bottom surface of the elliptical cam 33, the friction force generated by the reverse rotation of the nut 20 causes the elliptical cam 33 to rotate around the axis of the support pin 32. Figure 1 As shown in the clockwise rotation, the top surface of the elliptical cam 33 presses against the lower spring seat 41 and gradually moves it upward, the compression spring 43 is compressed, and the bottom surface of the elliptical cam 33 presses against the nut 20 and moves it downward. Due to the elastic force generated by the compression spring 43, the upper spring seat 42 pulls the optical axis segment 12 upward, and the mating nut 20 is pressed down by the elliptical cam 33, so that the nut 20 is re-engaged in the threaded segment 11 to achieve engagement, as shown in FIG. Figure 3 shown.

[0028] Afterwards, as the nut 20 continues to reverse, the lead screw 10 gradually moves upward, and the bottom surface of the elliptical cam 33 no longer contacts the end surface of the nut 20, that is, the rotation of the elliptical cam 33 loses support, and the elastic force of the compression spring 43 causes the lower spring seat 41 to move downward and reset, thereby pushing the elliptical cam 33 around the axis of the support pin 32 as shown in FIG. Figure 3 The elliptical cam 33 rotates counterclockwise as shown, so that the elliptical cam 33 returns to the initial state. Example

[0029] As a further optimization of the solution of the present application, on the basis of Example 1, in order to realize the sliding and sliding limitation of the lower spring seat 41, sliding blocks are evenly arranged on the inner wall of the lower spring seat 41 and around its central axis, and a vertical sliding groove is formed on the outer wall of the small diameter section of the optical axis segment 12 corresponding to the sliding block, and the sliding block is stuck in the vertical sliding groove and slidably connected. Example

[0030] As a further optimization of the solution of the present application, based on Example 1, the nut 20 can be connected to a gear through the outer wall, and the gear can be driven by a motor to drive the nut 20 to rotate.

[0031] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying 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 a limitation on the present invention.

[0032] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0033] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An automatic clutch device for a screw transmission end, characterized in that: It includes a lead screw, a nut, a cam clutch mechanism and a pre-tightening spring mechanism; the lead screw is an integrally formed structure, including a threaded section and an optical axis section with a collinear central axis, the longitudinal cross-section of the optical axis section is a "convex"-shaped structure and the end of its large-diameter section is connected to the threaded section; the nut is coaxially arranged on the outer wall of the lead screw and its inner hole wall can be threadedly connected to the threaded section; the cam clutch mechanism is coaxially arranged on the side of the nut away from the threaded section, including a support sleeve, a support pin, an elliptical cam and a limit pin, the support sleeve is arranged at the "convex"-shaped structure shoulder of the optical axis section and is sleeved on the outer wall of the small-diameter section of the optical axis section, a plurality of support pins are evenly arranged outside the support sleeve and around its axis, the outer walls of the support pins are rotated to sleeve the elliptical cams respectively, and the limit pins are fixedly arranged on the outer wall of the support sleeve corresponding to the elliptical cam and are located obliquely below the support pin; the pre-tightening spring mechanism is coaxially arranged on the side of the cam clutch mechanism away from the nut.

2. The automatic clutch device for a screw transmission end according to claim 1, characterized in that: The elliptical cam is eccentrically sleeved on the outer wall of the support pin shaft, and the center of the elliptical cam has a downward eccentric distance δ relative to the center of the support pin shaft in the direction of the long axis of the elliptical cam.

3. The automatic clutch device for a screw transmission end according to claim 1 or 2, characterized in that: The side wall of the elliptical cam away from the supporting sleeve is limited by a retaining spring.

4. The automatic clutch device for a screw transmission end according to any one of claims 1 to 3, characterized in that: The elliptical cam and the limiting pin are arranged in a ring array around the center of the supporting sleeve.

5. The automatic clutch device for a screw transmission end according to claim 1 or 4, characterized in that: The preload spring mechanism includes a lower spring seat, an upper spring seat and a compression spring; the lower spring seat is located on the side of the support sleeve away from the nut and its inner wall is slidably connected to the outer wall of the small diameter section of the optical axis segment, the upper spring seat is fixedly connected to the end of the small diameter section of the optical axis segment and the upper spring seat and the lower spring seat are connected by a compression spring, and the compression spring is located on the outer ring of the optical axis segment.

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