Ring-toothed roller worm and gear rotary table

Abstract

A ring-tooth roller worm gear rotary table belongs to the field of machinery. Its structure comprises three main components: a worm gear assembly, a worm, and supporting components. The basic assembly relationship is as follows: under the constraint of the supporting components, including the housing and bearings, a worm-driven worm gear transmission relationship is formed. A closed tooth root limiting groove is machined at the root of the worm gear teeth in the worm gear assembly. A tooth flank bearing surface is machined above the tooth root limiting groove. The worm's helical teeth are symmetrically distributed on both sides of the central section, divided into independent left and right helical tooth sections. Torque transmission between the worm gear and worm is achieved through the rolling friction of steel balls. It can be widely used in fields requiring precision and high torque.

Description

Technical Field

[0001] This invention belongs to the field of mechanical and electronic technology. More precisely, it is a worm gear mechanism that uses rollers or balls mounted on the worm gear as a substitute for tooth contact, in order to improve operating accuracy and suppress high friction. Background Technology

[0002] Worm gear structures are commonly used to transmit motion and power between two intersecting shafts. The worm wheel and worm are analogous to a gear and rack in their midplane, and the worm itself is similar in shape to a screw.

[0003] Basic parameters: module m, pressure angle, worm diameter coefficient q, lead angle, number of worm threads, number of worm wheel teeth, addendum coefficient (taken as 1), and clearance coefficient (taken as 0.2). Among these, module m and pressure angle refer to the module and pressure angle of the worm shaft surface, i.e., the module and pressure angle of the worm wheel end face, and both are standard values; the worm diameter coefficient q is the ratio of the worm's pitch circle diameter to its module m.

[0004] Operating characteristics: It can achieve a large transmission ratio and is more compact than the staggered-axis helical gear mechanism. The meshing tooth surfaces of the two gears are in line contact, resulting in a significantly higher load-bearing capacity than the staggered-axis helical gear mechanism. Worm gear transmission is equivalent to helical transmission, a multi-tooth meshing transmission, thus providing smooth transmission and very low noise. It has self-locking properties. When the lead angle of the worm is less than the equivalent friction angle between the meshing gear teeth, the mechanism has self-locking properties, achieving reverse self-locking, meaning only the worm can drive the worm wheel, and not the other way around. For example, in self-locking worm gear mechanisms used in lifting machinery, the reverse self-locking property provides safety protection. However, the transmission efficiency is relatively low, and wear is more severe. During worm gear meshing transmission, the relative sliding speed between the meshing gear teeth is high, resulting in high friction loss and low efficiency. Furthermore, the high relative sliding speed leads to severe tooth surface wear and heat generation. To dissipate heat and reduce wear, expensive materials with good friction-reducing and wear-resistant properties, as well as good lubrication devices, are often used, resulting in high costs. The worm has a large axial force.

[0005] Advantages and disadvantages overview:

[0006] Compared with other forms of gear transmission, worm gear drives have the following advantages and disadvantages.

[0007] Advantages: *Large single-stage speed ratio: The maximum single-stage speed ratio of bevel gear drives and spur gear drives is generally around 1 / 10, while worm gear drives with speed ratios of 1 / 70-1 / 100 are easy to manufacture. Therefore, worm gear reducers can achieve large speed ratios with relatively small overall dimensions. For example, comparing worm gear reducers with speed ratios of 1 / 5, 1 / 25, 1 / 70, and 1 / 150 with helical gear reducers, their power transmission is 30 horsepower, and their input shaft speed is 1200 rpm.

[0008] *Low noise and vibration during operation: When reciprocating gears and bevel gears mesh, they mainly engage in rolling contact, while worm gears mainly engage in sliding contact. Therefore, there are fewer factors that generate noise and vibration. For this reason, worm gear reducers are preferred for driving escalators, elevators, moving walkways, and, in recent years, machines designed to prevent pollution.

[0009] *Use a worm gear reducer. The shafts can be arranged perpendicularly without intersecting each other: the arrangement of the worm shaft and worm wheel shaft can sometimes be both convenient and reasonable, saving installation space for the prime mover and driven mover.

[0010] *It can prevent reverse rotation: When the worm lead angle is less than the friction angle, theoretically, the worm gear cannot drive the worm, meaning a self-locking worm gear transmission device can be designed. However, in reality, the tooth surface friction coefficient changes from static friction coefficient to dynamic friction coefficient due to vibration and other reasons, so it may rotate slowly at times, making it difficult to achieve complete self-locking.

[0011] Disadvantages: * Existing worm gear mechanisms all use a common high-friction tooth contact operation method, which not only results in low transmission efficiency and tooth backlash, but also has a very limited contact area between the teeth.

[0012] *Low efficiency: Compared to other types of N-gear drives, worm gear drives suffer from high tooth surface friction losses and low efficiency when transmitting power. Currently, due to improvements in manufacturing methods, near-theoretical efficiencies can be achieved; some worm gear drives reach 98% efficiency at a speed ratio of 1 / 5 and a worm speed of 180 rpm. However, with the same center distance, if the speed ratio is 1 / 70 and the worm speed is 200 rpm, the efficiency is approximately 60%.

[0013] *Prone to tooth surface adhesion: Involute cylindrical gears, when subjected to load, experience a positive change in tooth contact due to deformation of various parts. However, in worm gear drives, the tooth contact changes negatively, deforming towards the rupture of the oil film on the tooth surface, making tooth surface adhesion more likely. Therefore, the amount of deformation should be estimated and adjusted during assembly to ensure proper tooth contact and bearing clearance. Furthermore, careful running-in operation is essential.

[0014] *Lifespan and cost issues: Worm gear drives use copper alloy materials. Since dedicated gear cutting machines are generally unavailable, gear cutting efficiency is low, and manual tooth surface dressing is very time-consuming. Summary of the Invention

[0015] The purpose of this invention:

[0016] Overcoming the shortcomings of existing technologies, the high-friction contact between the worm gear and worm is improved by using the rolling friction of steel balls or rollers, and the disadvantages of low transmission efficiency, poor accuracy and limited service life are simplified.

[0017] The features of this invention are: the unique discrete guide groove cover structure simplifies the manufacturing process of the worm gear, resulting in a compact structure, high transmission efficiency and accuracy, and long service life.

[0018] The key technology of this invention is the creative use of steel ball rollers installed on the closed-loop return path around the worm gear to achieve rolling friction.

[0019] Specific details of the invention:

[0020] A ring-tooth roller worm gear rotary table comprises three main components: a worm gear assembly, a worm, and a support component. At the root of the worm gear teeth in the worm gear assembly, a closed tooth root limiting groove is machined, surrounding the worm gear teeth. A tooth flank bearing surface is machined on the upper part of the tooth root limiting groove. Each tooth flank is divided into a left tooth bearing surface and a right tooth bearing surface. A guide groove cover is machined on the guide groove cover. The guide groove cover is installed on the top of the worm gear teeth using methods including tight-fitting nesting, welding, and bonding, with the guide groove cover facing the tooth root limiting groove. The side of the roller is attached to the tooth flank bearing surface of the worm gear, and two thin shaft portions of the roller end shaft are respectively inserted into the guide groove cover groove and the tooth root limiting groove.

[0021] It is divided into a bearing surface on the left side of the tooth and a bearing surface on the right side of the tooth; the tooth bottom limiting groove and guide groove cover groove limit and attitude control method is that the roller end shaft free ring is an optional component. The ring hole fits into the thin shaft part of the roller end shaft and can rotate freely (because the turbine tooth is a frustum shape with a larger bottom and a smaller top, the wheelbase between the roller end shafts located at the tooth bottom limiting groove is greater than the wheelbase between the roller end shafts located at the guide groove cover groove; in this way, when the rollers approach each other, only the adjacent roller end shaft free rings will directly touch each other. Therefore, the limiting isolation of the roller end shaft free ring avoids the running contact between the roller working surfaces, thereby eliminating the strong friction between the rollers).

[0022] The basic assembly relationship is the same as that of a conventional worm gear reducer: the worm gear transmission relationship is formed under the support constraints of supporting components including: cover (housing), bearings, connecting parts, etc.; the helical teeth of the worm are independent helical teeth symmetrically distributed on both sides of the central section, divided into the left helical teeth and the right helical teeth of the worm. The side of the tooth closest to the central section is the inner side of the tooth, and the other side is the outer side of the tooth. The core technology of this invention lies in the following: the left and right helical teeth of the worm gear respectively contact the rollers on the right and left bearing surfaces of the worm wheel teeth, while not contacting the rollers on the left and right bearing surfaces of the worm wheel teeth; or conversely, the left and right helical teeth of the worm gear respectively contact the rollers on the left and right bearing surfaces of the worm wheel teeth, while not contacting the rollers on the right and left bearing surfaces of the worm wheel teeth; that is, the teeth at both ends of the worm are two independent sets of worm teeth, and the spacing between the two sets of independent worm teeth is controlled so that one side of the teeth at both ends of the worm contacts the worm wheel teeth, either the inner side of the worm helical teeth at both ends or the outer side of the worm helical teeth at both ends; without hindering the closed-loop circulation of the rollers (more specifically: The roller group is arranged around the turbine tooth and rolls around the turbine tooth, so that only the worm gear helical tooth is allowed to contact the roller group on one side of the same turbine tooth, so as not to hinder the closed-loop circulation of the rollers.

[0023] It is through the contact of rollers or balls that the force between the teeth is transmitted to the worm gear teeth, thereby reducing wear and friction. When an angular displacement (torque input) is applied to the worm shaft, the worm drives the worm gear assembly to generate an angular displacement. The turntable surface of the worm gear assembly then serves as the power output shaft, outputting the angular displacement (rotational displacement). When the worm is turning left or right, driving the worm gear, the inner surfaces of all the teeth of the left and right helical teeth of the worm are affected. All the outer surfaces of the teeth contact the rollers on the right and left bearing surfaces of the teeth, respectively. When the worm is turned counterclockwise, the left helical teeth of the worm push the rollers on the right bearing surface of the worm wheel teeth. When the worm is turned clockwise, the right helical teeth of the worm push the rollers on the left bearing surface of the worm wheel teeth, and vice versa. (In current practical applications, the spacing between the independent worm teeth at the left and right ends of the worm can be adjusted axially to eliminate wear clearance; or the wheelbase between the worm wheel and worm can be adjusted (reduced) to compensate for some wear.)

[0024] Working principle of ring-tooth roller worm gear rotary table:

[0025] The basic kinematic relationship between the worm gear assembly and the worm of this invention conforms to the operating rules of conventional worm gear reducers. The innovation lies in the installation of rollers or balls with a self-circulating motion mode around the worm teeth of the worm gear assembly. The torque transmission between the worm gear and worm is achieved through the rolling friction of the rollers or balls. Since the worm teeth only contact one side of the worm gear teeth, the closed-loop circulation of the rollers or balls is not hindered (because the movement of the rollers or balls installed around the same worm tooth forms a closed loop, and the movement directions of the rollers or balls installed around the opposite sides of the loop are opposite; if the left and right sides of the worm teeth and the worm helical teeth were in contact simultaneously, the movement would interfere and become unsustainable).

[0026] Furthermore: In addition to being a roller end shaft structure with a thin shaft, a roller or needle roller also includes grooves or ridges on the side of the roller for posture maintenance; the corresponding worm gear sidewall is machined with ridges or grooves that match the side of the roller; the interlocking between the ridges or grooves provides the roller with posture maintenance and prevents it from tipping over; the shape of the roller includes cylindrical and conical (frustum) shapes to suit the frustum shape of the worm gear which is larger at the bottom and smaller at the top.

[0027] Further: When using ball bearings, the situation is simpler. The cross-sectional shape of the guide groove, cover groove and tooth bottom limiting groove must match the spherical shape of the ball (near the pole). The cross-section includes a chamfered shape, so that the ball is exposed and can contact the worm gear, while restraining the ball from falling out.

[0028] Further: Allowing the addition of a preload spring or tension spring between the left and right helical teeth of the worm, enabling independent axial movement of either the left or right helical teeth; this involves machining the left or right helical teeth of the worm into hollow, sleeve-shaped sections that can move independently along the worm shaft, thus compensating for wear.

[0029] The technological advancement of this invention is that it completely overcomes the disadvantage of high friction in worm gears, providing a ball torque transmission mechanism with good linear output, simple structure, easy processing, and simultaneously possessing advantages such as high precision, high rigidity, high torque transmission, and long service life. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments:

[0031] [ Figure 1 Schematic diagram of the ring-tooth roller worm gear turntable structure.

[0032] [ Figure 2 Exploded view of a ring-tooth roller worm gear turntable.

[0033] [ Figure 3 ] Partial schematic diagram of the guide channel cover and skirt.

[0034] [ Figure 4 Schematic diagram of worm gear meshing relationship Figure 1

[0035] [ Figure 5 Schematic diagram of worm gear meshing relationship Figure 2

[0036] [ Figure 6 ] Schematic diagram of roller structure.

[0037] Explanation of the labels in the diagram:

[0038] 1 Worm Gear Assembly

[0039] 1-1 Turntable surface (power take-off shaft)

[0040] 1-2 worm gear teeth

[0041] 1-3 Tooth Bottom Limiting Groove

[0042] 1-4 Tooth flank bearing surface

[0043] 1-5 rollers

[0044] 1-6 Roller End Shaft

[0045] 1-7 Roller end shaft free ring

[0046] 1-8 guide slot cover

[0047] 1-9 Guide groove skirt

[0048] 1-10 Guide groove cover groove

[0049] 1-11 Guide groove cover docking part

[0050] 1-12 Left side bearing surface

[0051] Right side bearing surface of teeth 1-13

[0052] 1-14 Worm Gear Shaft

[0053] 1-15 Turbo

[0054] 2 worm gears

[0055] 2-1 Worm Shaft (Power Input Shaft)

[0056] 2-2 Worm Helical Gear

[0057] 2-3 Left helical teeth of the worm gear

[0058] 2-4 Right helical teeth of the worm

[0059] Inner surface of teeth 2-5

[0060] 2-6 outer surfaces

[0061] 2-7 Central Section

[0062] 3 Supporting components

[0063] 3-1 Cover

[0064] 4 Bottom view of the guide channel cover

[0065] 5. Enlarged view of the bottom of the guide channel cover Detailed Implementation

[0066] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown:

[0067] The ring-tooth roller worm gear turntable includes three main components: worm gear assembly (1), worm (2) and support component (3); at the root of the tooth root of the worm gear tooth (1-2) of the worm gear (15) on the worm gear assembly (1), a closed tooth root limiting groove (1-3) is machined around the tooth root of the worm gear tooth, and a tooth side bearing surface (1-4) is machined on the upper part of the tooth root limiting groove (1-3). The side of each tooth is divided into a tooth left bearing surface (1-12) and a tooth right bearing surface (1-13); the guide groove cover skirt (1-9) is machined with a guide groove cover groove (1-10).

[0068] Especially in Figure 2 The enlarged views of the guide cover bottom (4) and the enlarged view of the guide cover bottom (5) show that the guide cover mating part (1-11) of the guide cover (1-8) is mated and installed with the top of the worm gear tooth (1-2) by mating methods including tight fitting, welding and bonding; the guide cover groove (1-10) faces the tooth bottom limiting groove (1-3); the side of the roller (1-5) is attached to the tooth side bearing surface (1-4) of the worm gear tooth, and the two thin shaft parts of the roller end shaft (1-6) are inserted into the guide cover groove (1-10) and the tooth bottom limiting groove (1-3) respectively.

[0069] Especially in Figure 6As can be seen from the diagram: the tooth is divided into a bearing surface on the left side (1-12) and a bearing surface on the right side (1-13); the tooth bottom limiting groove (1-3) and the guide groove cover groove (1-10) limit and attitude control method is that the roller end shaft free ring (1-7) is an optional component. The ring hole is fitted into the thin shaft part of the roller end shaft (1-6) and can rotate freely (because the turbine tooth is a frustum shape with a larger bottom and a smaller top, the wheelbase between the roller end shafts (1-6) located at the tooth bottom limiting groove (1-3) is greater than the wheelbase between the roller end shafts located at the guide groove cover groove; in this way, when the rollers approach each other, only the adjacent roller end shaft free rings will directly touch each other. Therefore, the limiting isolation of the roller end shaft free ring (1-7) avoids the running contact between the roller working surfaces, thereby eliminating the strong friction between the rollers).

[0070] The basic assembly relationship is that of a conventional worm gear reducer: the worm gear transmission relationship is formed under the support constraints of the supporting component (3), including: cover (3-1) (housing), bearings, connecting parts (screws connecting the housing, etc.); the helical teeth (2-2) of the worm (2) are symmetrically distributed on: Figure 4 The independent helical teeth on both sides of the central section (2-7) (i.e., at line segment AB) are divided into the left helical teeth (2-3) and the right helical teeth (2-4) of the worm. The side of the tooth closest to the central section (2-7) is the inner side of the tooth, and the other side is the outer side of the tooth. The core technology of this invention is that the left helical teeth (2-3) and the right helical teeth (2-4) of the worm respectively contact the rollers on the right bearing surface (1-13) and the left bearing surface (1-12) of the worm gear tooth (1-2), but do not contact the rollers (1-5) on the left bearing surface (1-12) and the right bearing surface (1-13) of the worm gear tooth; or the opposite, the left helical teeth (2-3) and the right helical teeth (2-4) of the worm respectively contact the rollers (1-13) and the right bearing surface (1-12) of the worm gear tooth (1-13). 2) The rollers on the left bearing surface (1-12) and right bearing surface (1-13) of the worm tooth are in contact with each other, but not with the rollers on the right bearing surface (1-13) and left bearing surface (1-12) of the worm gear tooth respectively; that is, the teeth at both ends of the worm are two sets of independent worm teeth. The spacing between the two sets of independent worm teeth is controlled so that one side of the teeth at both ends of the worm contacts the worm gear tooth, either the inner side of the worm helical teeth at both ends or the outer side of the worm helical teeth at both ends; so as not to hinder the closed-loop circulation of the rollers.

[0071] It is through the contact between the rollers or balls that the rollers or balls act as a medium to transmit the force between the teeth to the worm gear teeth (1-2), thereby reducing wear and friction; when the worm shaft (2-1) of the worm (2) is subjected to angular displacement input (torque input), the worm drives the worm gear assembly (1) to generate angular displacement, and then the turntable surface (1-1) of the worm gear assembly (1) serves as the power output shaft in the direction of the worm gear axis (1-14) to output angular displacement (rotational displacement output); when the worm is rotating to the left or right to drive the worm gear, the inner surface (2-5) or outer surface (2-6) of the left helical teeth (2-3) and the right helical teeth (2-4) of the worm respectively contact the rollers on the right bearing surface (1-13) and the left bearing surface (1-12) of the tooth; In short, either all the inner surfaces of the worm teeth or all the outer surfaces of the teeth are used simultaneously; that is, when the worm is turned left, the left helical teeth (2-3) of the worm push the rollers on the right bearing surface (1-13) of the worm wheel teeth; when the worm is turned right, the right helical teeth (2-4) of the worm push the left bearing surface (1-12) of the worm wheel teeth through the rollers, and vice versa. (In existing practical applications, the spacing between the independent worm helical teeth (2-2) at the left and right ends of the worm can be adjusted axially to eliminate wear clearance; or the wheelbase between the worm wheel and worm can be adjusted (reduced) to compensate for some wear).

Claims

1. A ring-tooth type roller worm gear turntable comprises three main components: a worm gear assembly, a worm, and a support component. The basic assembly relationship is as follows: under the constraint of the support component, including the housing and bearings, a worm gear transmission relationship is formed where the worm drives the worm wheel. The worm helical teeth and the worm gear teeth are in contact via rollers or balls. When an angular displacement is input to the worm shaft, the worm drives the worm gear assembly to generate an angular displacement, which is then output via the turntable surface of the worm gear assembly as the power output shaft. When the worm is rotating left or right, driving the worm wheel, the left and right helical teeth of the worm contact the rollers on the right and left bearing surfaces of the teeth, respectively. When the worm rotates left, the left helical teeth of the worm drive the rollers on the right bearing surface of the worm wheel teeth; when the worm rotates right, the right helical teeth of the worm drive the rollers on the left bearing surface of the worm wheel teeth, and vice versa. Its characteristics are: One of the key technologies lies in the following: A closed, surrounding tooth root limiting groove is machined at the root of the worm gear teeth in the worm gear assembly. A tooth flank bearing surface is machined above the tooth root limiting groove, divided into a left tooth flank bearing surface and a right tooth flank bearing surface. A closed guide groove is machined on the guide skirt, and the guide skirt is installed on the top of the worm gear teeth. The mating of the guide skirt with the top of the worm gear teeth includes tight fitting, welding, and bonding. After installation, the guide skirt faces the tooth root limiting groove. The side of the roller is pressed against the tooth flank bearing surface of the worm gear teeth. The two end shafts are respectively inserted into the closed guide skirt groove and the tooth bottom limiting groove. The upper and lower tooth bottom limiting grooves and the guide skirt groove constrain the roller posture and move along the closed path of the upper and lower grooves. The free ring on the roller end shaft is an optional component. The free ring hole is fitted into the thin shaft part of the roller end shaft. When the rollers touch each other, the free ring is in contact. When using ball bearings, the cross-sectional shape of the guide skirt groove and the tooth bottom limiting groove must match the spherical shape of the ball bearing. The cross-section includes the chamfer shape, so that the ball bearing is exposed and can contact the worm gear, while also constraining the ball bearing to prevent it from falling out. The second key technology lies in the fact that the helical teeth of the worm are symmetrically distributed on both sides of the central section, divided into independent left and right helical teeth. The side of the helical teeth closest to the central section is the inner side of the tooth, and the other side is the outer side. The left and right helical teeth of the worm contact the rollers on the left and right bearing surfaces of the worm wheel teeth, respectively, but do not contact the rollers on the right and left bearing surfaces of the worm wheel teeth, and vice versa. In other words, the spacing between the two independent worm helical teeth is controlled so that one side of the teeth at both ends of the worm contacts the worm wheel teeth, either the inner side of the helical teeth at both ends contacts the rollers, or the outer side of the helical teeth at both ends contacts the rollers. Since the worm teeth only contact one side of the worm wheel teeth, they do not hinder the closed-loop circulation of the balls or rollers. This is because the movement of the rollers or balls installed around the same worm tooth forms a closed loop, and the movement directions of the rollers or balls installed around the opposite sides of the loop are opposite. If the left and right sides of the worm teeth and the worm helical teeth are in contact at the same time, the closed movement of the rollers will not be possible.

2. A ring-tooth roller worm gear rotary table according to claim 1, characterized in that: In addition to being a roller end shaft structure with a thin shaft, the roller also includes grooves or ridges on its side for posture maintenance; the corresponding worm gear sidewalls are machined with ridges or grooves that match the roller sidewalls; the interlocking of the ridges or grooves provides the roller with a running posture that prevents it from tipping over; the roller's shape also includes a frustum shape to suit the frustum shape of the worm gear, which is larger at the bottom and smaller at the top; the roller can also be replaced by a needle roller.

3. A ring-tooth roller worm gear rotary table according to claim 1, characterized in that: The left or right helical teeth of the worm are integrally machined on the worm shaft, or at least one part is machined into a hollow tube-shaped left or right helical tooth portion that can move independently along the worm shaft axially. A spring for pre-tensioning thrust or tension is added between the left and right helical teeth of the worm, so that the left or right helical teeth of the worm can move independently axially.

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