A high-rigidity screw elevator of a lead screw movement type based on a thrust needle bearing

Abstract

This utility model discloses a high-rigidity screw jack based on a thrust needle roller bearing, characterized by comprising a screw, an anti-rotation disc, a housing, and a lifting plate; the housing contains a worm, a thrust needle roller bearing, and a worm wheel; the screw is a variable-diameter screw, with the lower trapezoidal screw engaging with the trapezoidal internal thread of the worm wheel for self-locking when stationary; the head diameter of the screw is smaller than the lower trapezoidal screw diameter, forming a positioning shoulder at the diameter change; the lifting plate has a through hole for mounting the screw; the lifting plate is positioned by being secured to the positioning shoulder through the through hole; the worm rotates under the drive force, driving the worm wheel to rotate via gear transmission; a set of thrust needle roller bearings are installed above and below the worm wheel, and the worm wheel drives the screw to move axially; the anti-rotation disc is fixed to the housing; keyways are provided on both the screw and the anti-rotation disc, allowing the screw to move only axially and not rotate. This application features a compact structure and high rigidity.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical design technology and relates to a high-rigidity screw jack based on a thrust needle roller bearing. Background Technology

[0002] A screw jack is a mechanical transmission device that achieves lifting motion based on the principle of screw drive. Its core function is to convert the rotary motion input by a motor or manual input into the linear motion of the load. It is widely used in industrial automation, precision machinery, and other fields. Its main core components include a lead screw, a worm gear, a guide mechanism, support bearings, and a drive interface. Screw jacks are classified into two types based on the different linear motion components: nut-motion type (the nut moves along the lead screw axis) and lead screw-motion type (the lead screw moves along its own axis). Lead screw heads generally come in cylindrical, flange, pin-hole, fork-pin, and spherical hinge types. The screw jack of this invention belongs to the lead screw-motion type. The closest implementation to this invention is a lead screw-motion type screw jack with thrust roller bearings. Its main structural components include a lead screw, a worm gear, a guide mechanism, thrust roller bearings, and an external housing.

[0003] Ball bearings and roller bearings occupy more vertical space than needle roller bearings. Furthermore, when the plate being lifted needs to be supported and raised, at least three support points are required. If the heights of these three support points are inconsistent, uneven stress will occur on the plate. This invention addresses this issue by incorporating two spherical washers into the lead screw head. During use, the upper and lower surfaces of the plate being lifted are machined with conical surfaces to accommodate the spherical washers, thus allowing for uneven stress distribution caused by inconsistent support point heights. Utility Model Content

[0004] To address the problems existing in the prior art, the purpose of this utility model is to provide a high-rigidity screw jack based on a thrust needle roller bearing. Compared to other bearing types, the thrust needle roller bearing has a smaller vertical footprint, provides greater load-bearing capacity, and exhibits higher rigidity, making it more suitable for applications with high load requirements, limited installation space, and high stability requirements. Furthermore, the screw head of this jack features a variable diameter to form a shoulder, which, in combination with spherical washers and other structures, allows for situations where multiple jacks are used to lift plates, resulting in the plates not being perfectly perpendicular to the screw. This prevents uneven stress on the plates, which could negatively impact the mechanical structure's safety, precision, and service life. This utility model solves the problem of achieving high load capacity and high rigidity within a smaller volume; and it also solves the problem of uneven stress on plates caused by inconsistent heights when multiple screw jacks support and lift them.

[0005] The technical solution of this utility model is as follows: A high-rigidity screw jack based on a thrust needle roller bearing, characterized in that it includes a screw 1, an anti-rotation disc 4, a housing 5, and a lifting plate 12; the housing 5 is provided with a worm gear 2, a thrust needle roller bearing 3, and a worm wheel 6. The lead screw 1 is a variable diameter lead screw, and the lower part of the lead screw 1 is a trapezoidal lead screw. The trapezoidal lead screw is engaged with the trapezoidal internal thread of the worm gear 6 for movement, and is used to achieve self-locking when stationary. The diameter of the head of the lead screw 1 is smaller than the diameter of the lower trapezoidal lead screw, and a positioning shoulder 15 is formed at the diameter change; the lifting plate 12 is machined with a through hole for mounting the lead screw 1; the lifting plate 12 is positioned by being engaged with the positioning shoulder 15 through the through hole. The worm 2 is used to rotate under the drive of the driving force, and the worm 2 drives the worm wheel 6 to rotate through gear transmission; The worm wheel 6 is equipped with a set of thrust needle roller bearings 3 on its upper and lower sides, respectively, to reduce the friction between the worm wheel and the housing when the worm wheel rotates and to constrain the worm wheel 6 from moving along the axial direction, so that it can only rotate, thereby driving the lead screw 1 to move along the axial direction. The anti-rotation disk 4 is fixed on the housing 5; the lead screw 1 and the anti-rotation disk 4 are respectively provided with keyways 16, and are installed in the keyways 16 by key 11, so that the lead screw 1 can only move along the axial direction and does not rotate.

[0006] Preferably, it also includes a first locking nut 8, the internal thread of the first locking nut 8 being a trapezoidal thread, the internal thread of the first locking nut 8 engaging with the trapezoidal thread on the lead screw 1 to lock the housing 5 onto the mounting plate of the screw jack.

[0007] Preferably, the thrust needle roller bearing 3 has a through hole in the middle that is larger than the diameter of the lead screw 1, for fitting onto the lead screw 1.

[0008] Preferably, it further includes a second locking nut 10, which is disposed on the lead screw 1. When adjusting the lifting plate 12, the second locking nut 10 is in a loose state, and after the position of the lifting plate 12 is adjusted, the second locking nut 10 is locked to fix the position of the lifting plate 12.

[0009] Preferably, the anti-rotation disc 4 is fixed to the housing 5 by a plurality of fixing bolts 13.

[0010] Preferably, the housing 5 is provided with a housing cover 7 for pressing the worm gear 6 and the thrust needle roller bearing 3.

[0011] Preferably, the two ends of the through hole on the lifting plate 12 are machined with tapered holes 14 that mate with the spherical washer 9. After the lifting plate 12 mates with the spherical washer 9 through the tapered holes 14, it is positioned on the positioning shoulder 15.

[0012] The key features of this utility model include: (1) The internal bearings of the elevator use thrust needle roller bearings that occupy less space and can still provide a large load-bearing capacity with a very small thickness; (2) The lower half of the screw is a trapezoidal screw with a triangular thread at the head. Two ball washers are installed on it, which allows the clamped lifting plate to be installed not completely perpendicular to the screw, so that the height requirements of multiple machines lifting the plate at the same time can be achieved. (3) The elevator has double locking, including trapezoidal screw self-locking and nut locking.

[0013] The advantages of this utility model are as follows: 1) The screw jack in this utility model is compact in size and occupies less space in height compared to ball bearings and roller bearings under the same load, making it more suitable for occasions with limited installation space; 2) The screw jack in this utility model adopts a double locking structure, which can achieve higher rigidity of the jack and improve the stability of the entire system using the jack; 3) Typically, a single piece of equipment requires multiple points of support from a screw jack for adjustment. If the heights of these multiple points are inconsistent, stress may occur on the supporting plates. This solution uses spherical washers in conjunction with tapered holes to address this issue. Attached Figure Description

[0014] Figure 1 This is a structural diagram of the high-rigidity screw jack based on a thrust needle roller bearing, as described in this application.

[0015] Figure 2 This is a cross-sectional view of the screw jack and the lifted plate of this application.

[0016] Figure 3 This is a diagram of the lead screw structure.

[0017] Figure 4 A structural diagram for preventing the turntable from turning.

[0018] Figure 5 This is a bottom view of the screw jack.

[0019] 1-Lead screw; 2-Worm gear; 3-Thrust needle roller bearing; 4-Anti-rotation disc; 5-Box housing; 6-Worm gear; 7-Box housing cover; 8-First locking nut; 9-Spherical washer; 10-Second locking nut; 11-Key; 12-Lifted plate; 13-Turntable fixing bolt; 14-Conical hole; 15-Positioning shoulder; 16-Keyway. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0021] The structure of this utility model is as follows: Figure 1 As shown, the lead screw 1 is a variable diameter lead screw, and the lower part of the lead screw 1 is a trapezoidal lead screw that engages with the trapezoidal internal thread of the worm gear 6 for movement. When stationary, it can achieve self-locking. Simultaneously, the internal thread of the first locking nut 8 is also a trapezoidal thread, which further tightens and improves the overall rigidity and stability of the lifting platform. The first locking nut 8 engages with the trapezoidal thread on the lead screw 1 to lock the entire screw jack housing 5 to the mounting plate of the screw jack. The head diameter of the lead screw 1 is smaller than the diameter of the lower trapezoidal lead screw, forming a positioning shoulder 15 at the diameter change point. The driving force drives the worm gear 2 to rotate, and the worm gear 2 drives the worm wheel 6 to rotate through gear transmission. The worm wheel 6 is constrained by two sets of thrust needle roller bearings 3, one above and one below, and cannot move along the axial direction, but can only rotate. The thrust needle roller bearings 3 can also reduce the friction between the worm wheel and the housing when it rotates. The thrust needle roller bearings 3 have a through hole in the middle that is larger than the diameter of the lead screw 1, and are directly fitted onto the lead screw 1. They are pressed by the housing cover 7, so that the worm wheel 6 cannot move axially. The housing cover 7 is fixed to the housing 5 by threads, pressing the worm wheel 6 and the thrust needle roller bearings 3 inside. Because the inner hole of the worm wheel 6 is a trapezoidal thread that mates with the lead screw 1, the lead screw 1 can move axially. The lead screw 1 and the anti-rotation disc 4 are designed with keyways 16. The anti-rotation disc 4 is fixed to the housing 5 by multiple fixing bolts 13. The installation of the key 11 ensures that the lead screw 1 can only move axially and cannot rotate. The key 11 is fixed to the anti-rotation disc 4 with a set screw to prevent it from falling off. The thrust needle roller bearing 3 is used in combination with one thrust washer on the top and one on the bottom. The lifting plate 12 has a through hole for mounting the lead screw 1. Tapered holes 14 are machined at both ends of the through hole to mate with the spherical washers 9, allowing the lifting plate 12 and the lead screw 1 to be slightly perpendicular. The tapered holes 14 on the lifting plate 12, after mate with the spherical washers 9, engage with the positioning shoulder 15 for positioning. When adjusting the lifting plate 12, the second locking nut 10 must be in a loose state. After adjusting the position of the lifting plate 12, the second locking nut 10 is tightened to fix the position of the lifting plate 12.

[0022] Thrust needle roller bearings can be used in combination with thrust washers, or they can be used alone if the contact surfaces of the worm gear and the housing are suitable.

[0023] The anti-rotation structure for the lead screw is not limited to the structure described in this solution; other structures can also be used to prevent the lead screw from rotating.

[0024] The first locking nut 8 is an unnecessary installation part. If the rigidity requirement is not high, this locking nut can be omitted.

[0025] Although specific embodiments of the present invention have been disclosed for illustrative purposes to aid in understanding and implementing the invention, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the content disclosed in the preferred embodiments, and the scope of protection claimed by the invention is defined by the claims.

Claims

1. A high-rigidity screw jack based on a thrust needle roller bearing, characterized in that, It includes a lead screw (1), an anti-rotation disc (4), a housing (5), and a lifting plate (12); the housing (5) is equipped with a worm gear (2), a thrust needle roller bearing (3), and a worm wheel (6); The lead screw (1) is a variable diameter lead screw, and the lower part of the lead screw (1) is a trapezoidal lead screw. The trapezoidal lead screw is engaged with the trapezoidal internal thread of the worm gear (6) for movement, and is used to achieve self-locking when stationary. The diameter of the head of the lead screw (1) is smaller than the diameter of the lower trapezoidal lead screw, and a positioning shoulder (15) is formed at the diameter change; the lifting plate (12) is machined with a through hole for mounting the lead screw (1); the lifting plate (12) is positioned by being secured to the positioning shoulder (15) through the through hole; The worm (2) is used to rotate under the drive of the driving force, and the worm (2) drives the worm wheel (6) to rotate through gear transmission; The worm wheel (6) is equipped with a set of thrust needle roller bearings (3) on its upper and lower sides respectively. These bearings are used to reduce the friction between the worm wheel and the housing when the worm wheel rotates and to constrain the worm wheel (6) from moving along the axial direction and to only rotate, thereby driving the lead screw (1) to move along the axial direction. The anti-rotation disk (4) is fixed on the housing (5); the lead screw (1) and the anti-rotation disk (4) are respectively provided with keyways (16), which are installed in the keyways (16) by key (11), so that the lead screw (1) can only move along the axial direction and does not rotate.

2. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, characterized in that, It also includes a first locking nut (8), the internal thread of the first locking nut (8) is a trapezoidal thread, the internal thread of the first locking nut (8) cooperates with the trapezoidal thread on the lead screw (1) to lock the housing (5) onto the mounting plate of the screw jack.

3. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, characterized in that, The thrust needle roller bearing (3) has a through hole in the middle that is larger than the diameter of the lead screw (1) for fitting onto the lead screw (1).

4. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, 2, or 3, characterized in that, It also includes a second locking nut (10), which is located on the lead screw (1) and is used to loosen the second locking nut (10) when adjusting the lifting plate (12), and lock the second locking nut (10) after adjusting the position of the lifting plate (12) to fix the position of the lifting plate (12).

5. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, 2, or 3, characterized in that, The anti-rotation disc (4) is fixed to the box body (5) by multiple fixing bolts (13).

6. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, 2, or 3, characterized in that, The housing (5) is provided with a housing cover (7) for pressing the worm gear (6) and the thrust needle roller bearing (3).

7. The high-rigidity screw jack based on a thrust needle roller bearing according to claim 1, characterized in that, The lifting plate (12) has tapered holes (14) at both ends of the through hole that mate with the spherical washer (9). The lifting plate (12) is positioned by engaging with the spherical washer (9) through the tapered hole (14) and then being positioned by engaging with the spherical washer (9) on the positioning shoulder (15).

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