High-rigidity precision ball worm and gear

Abstract

A high-rigidity precision ball worm gear belongs to the field of machinery. The turbine structurally comprises a turbine disc and a turbine shaft, and the worm structurally comprises a worm shaft and a spiral body. A groove with a semicircular section is formed in the peripheral cylindrical surface part of a turbine disc of the turbine; a group of inclined channels which are uniformly distributed at equal intervals are processed on the groove bottom surface of the closed ring groove; a spiral body of the worm is a columnar object with a spiral channel on one side surface, and return channels are arranged on two end surfaces of the worm; contact between the turbine and the worm is achieved through the steel balls clamped between the inclined channel and the spiral channel, the worm is made to rotate through power torque, then the turbine is pushed to rotate, meanwhile, the steel balls are made to move spirally along the spiral channel, and all the steel balls of the closed steel ball linear array generate follow-up queuing circulating displacement. And the method can be widely applied to the field with precise high-torque requirements.

Description

[Technical Field]

[0001] The present invention belongs to the field of mechatronics technology. Specifically, it is a worm and worm gear mechanism that uses rolling steel balls as similar tooth contacts to improve the running accuracy and suppress high friction. [Background Art]

[0002] The worm and worm gear structure is often used to transmit motion and power between two intersecting shafts. The worm and the worm gear are equivalent to a gear and a rack in their intermediate plane, and the worm is also similar in shape to a screw.

[0003] Basic parameters: module m, pressure angle, worm diameter coefficient q, lead angle, number of worm heads, number of worm gear teeth, addendum coefficient (take 1) and backlash coefficient (take 0.2). Among them, the module m and the pressure angle refer to the module and the pressure angle of the worm's axial plane, that is, the module and the pressure angle of the worm gear's end face, and both are standard values; the worm diameter coefficient q is the ratio of the worm's pitch diameter to its module m.

[0004] Operating characteristics: 1. A large transmission ratio can be obtained, which is more compact than the intersecting shaft helical gear mechanism. 2. The meshing tooth surfaces of the two wheels are in line contact, and its load-carrying capacity is much higher than that of the intersecting shaft helical gear mechanism. 3. The worm drive is equivalent to a screw drive and is a multi-tooth meshing drive, so the transmission is stable and the noise is very small. 4. It has self-locking property. When the lead angle of the worm is less than the equivalent friction angle between the meshing teeth, the mechanism has self-locking property and can achieve reverse self-locking, that is, only the worm can drive the worm gear, and the worm gear cannot drive the worm. For example, the self-locking worm mechanism used in hoisting machinery, its reverse self-locking property can play a safety protection role. 5. The transmission efficiency is relatively low and the wear is relatively serious. When the worm and worm gear are in meshing transmission, the relative sliding speed between the meshing teeth is large, so the friction loss is large and the efficiency is low. On the other hand, the large relative sliding speed causes serious tooth surface wear and heat generation. In order to dissipate heat and reduce wear, materials with relatively expensive anti-friction and anti-wear properties and good lubrication devices are often used, so the cost is relatively high. 6. The axial force of the worm is relatively large.

[0005] General situation of advantages and disadvantages:

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

[0007] Advantages:

[0008] Single-stage speed ratio is large:

[0009] The single-stage speed ratio of cylindrical gear transmission and bevel gear transmission is generally up to about 1 / 10 at most, while the worm and worm gear transmission with a speed ratio of 1 / 70 - 1 / 100 is easy to manufacture. Therefore, the worm and worm gear transmission reducer can achieve a large speed ratio with a smaller overall dimension. The comparison between worm and worm gear reducers with speed ratios of 1 / 5, 1 / 25, 1 / 70, and 1 / 150 and helical gear reducers. Their transmitted power is 30 horsepower and the input shaft speed is 1200 rpm.

[0010] Low noise and small vibration during operation: When cylindrical gears and bevel gears mesh, it is mainly rolling contact, while for worm gears, it is mainly sliding contact. Therefore, there are fewer factors causing noise and vibration. For this reason, worm and worm gear reducers are preferred for driving escalators, elevators, moving walkways, and machines for preventing public nuisances in recent years.

[0011] Using a worm and worm gear reducer, the shafts can be arranged vertically without intersecting: The arrangement of the worm shaft and the worm gear shaft can sometimes save the installation area of the prime mover and the driven machine and be convenient and reasonable.

[0012] Reverse rotation can be prevented: When the lead angle of the worm is less than the friction angle, theoretically the worm cannot be driven by the worm gear. That is to say, a self-locking worm drive device can be designed. However, in practice, the tooth surface friction coefficient changes from the static friction coefficient to the dynamic friction coefficient due to reasons such as vibration, so it may sometimes rotate slowly, and it is difficult to achieve complete self-locking.

[0013] Disadvantages: Existing worm and worm gear mechanisms all adopt the tooth contact operation mode with high friction between general-purpose components. In addition to low transmission efficiency and tooth clearance, the contact area of the contact line between teeth is also very limited.

[0014] Low efficiency: Compared with other forms of gear transmission, the tooth surface friction loss is large and the efficiency is low during the transmission of power in worm and worm gear transmission. Currently, due to the improvement of manufacturing methods, an efficiency close to the theoretical value can be achieved. For some worm and worm gear transmissions with a speed ratio of 1 / 5 and a worm speed of 180 rpm, the efficiency reaches 98%. However, with the same center distance, when the speed ratio is 1 / 70 and the worm speed is 200 rpm, the efficiency is about 60%.

[0015] Easy to generate tooth surface adhesion: For involute tooth form cylindrical gears, if the tooth surface bears a load, due to the deformation of each part, the tooth contact state changes for the better, while the tooth contact state of worm and worm gear transmission changes for the worse, that is, it deforms in the direction of tooth surface oil film rupture, and tooth surface adhesion is easy to occur. Therefore, the tooth contact state and bearing clearance during assembly should be estimated by considering the deformation amount. It is also necessary to carry out running-in operation as carefully as possible.

[0016] Lifespan and cost issues: The worm and worm gear drive uses copper alloy materials. Since there is generally no dedicated gear cutting machine, the gear cutting processing efficiency is low, and it takes a lot of time to manually trim the tooth surface. [Summary of the Invention]

[0017] Object of the present invention:

[0018] To overcome the deficiencies of the prior art, improve the high-friction contact mode between the worm and the worm gear, and improve the adverse factors such as low transmission efficiency and limited service life.

[0019] Features of the present invention: Compact structure, high transmission efficiency and transmission accuracy, and long service life.

[0020] Key technology of the present invention: Create the conditions for rolling friction, and cleverly utilize the steel ball string in the closed-loop return journey to achieve the replacement of sliding friction with the rolling friction of steel balls.

[0021] Specific content of the invention:

[0022] The high-rigidity precision ball worm and worm gear is composed of three major components: including the worm gear, the worm and the support component; among them, the structure of the worm gear includes the worm gear disk and the worm gear shaft, and the structure of the worm includes the worm shaft and the spiral body; the support component is provided with a worm shaft hole and a worm gear shaft hole, used to install and restrain the worm shaft and the worm gear shaft of the worm and the worm gear, and can rotate freely under the support of the bearing; since the support component connects the worm shaft hole and the worm gear shaft hole into a whole, a driving relationship is formed between the worm gear and the worm.

[0023] The structure of each component is as follows: the worm wheel component consists of a worm wheel disc and a worm wheel shaft (power output shaft). On the peripheral cylindrical surface of the worm wheel disc, a groove with a semicircular cross section is processed. The groove surrounds the circumference of the entire worm wheel disc to form a closed ring groove (semicircular cross section). The circumferential lines at both ends of the worm wheel are equivalent to the two sides of the closed ring groove. On the bottom surface of the above-mentioned ring groove, a group of equally spaced and evenly arranged non-intersecting oblique grooves are processed. The oblique groove has a semicircular cross section. The channel obliquely spans the "two banks" of the groove; the spiral body of the worm (pair) is a cylindrical object with a spiral channel on one side, and the spiral channel surrounds the cylindrical surface of the worm pair; and at the two ends of the spiral channel, there are ball return holes or through grooves aligned with the orifices of the ball guide tube, and the other end of the orifice of the ball guide tube is aligned with the return channel machined inside the worm and passing through the two end faces of the worm; the worm shaft and the worm wheel shaft are constrained by the worm shaft hole and the worm wheel shaft hole of the supporting component, and can be It rotates freely under the support; the constraint cover body part that is fastened to the support part covers the exposed half of the worm part, and the inner surface of the constraint cover body just contacts the steel balls with a certain gap; so that the steel balls do not leave the spiral groove and can slide freely; when the steel balls are used to fill the entire closed path composed of the spiral groove, the ball guide tube and the return channel, a closed array of steel balls is formed; but in the case of an opposed worm gear layout, there are two upper and lower worm gears docking with one worm, so there is no need to use the constraint cover body part, which naturally prevents the steel balls from slipping out; in order to increase the thrust, the matching spiral of the worm and the worm wheel can be single-headed or multi-headed, and the corresponding return channel is also increased to the number of heads; taking into account the mathematical geometric relationship of the relative uniform rotation of the closed ring groove of the spiral body and the worm wheel disk, only the steel balls in the local groove and spiral groove can meet the close contact relationship of operation without too large a gap, so multiple worms are required in series to meet the requirements of large load torque.

[0024] Working principle of high rigidity precision ball worm gear system:

[0025] Because the supporting component connects the worm shaft hole and the worm wheel shaft hole into a whole, a driving relationship is formed between the worm wheel and the worm; the mechanical contact between the worm wheel and the worm is achieved through the steel ball clamped between the oblique groove of the worm wheel and the spiral groove of the worm: It should be emphasized that the ball guide tube can be replaced by the curved holes directly machined at both ends of the worm (pair); the worm (pair) component can be used alone, and can also be used as a series torque increase for multiple worm (pair) components.

[0026] When the dynamic torque causes the worm to rotate, the steel balls generate a tangential force that moves forward and backward along the direction of the thread under the thrust of the thread. The pushing action between the steel balls transmits force and torque, thereby driving the worm wheel to rotate. At the same time, the steel balls also generate spiral motion along the spiral groove, and all the steel balls in the closed steel ball line produce a follow-up cyclic displacement.

[0027] Furthermore, in order to increase the transmission torque of the speed reduction mechanism, multiple worm components can be used in series; that is, the worms in the high-rigidity precision ball worm gears are connected in series. The worm shaft can extend to connect one end shaft of the shaft transmission assembly, and the other shaft end is then connected to the worm shaft of the next worm (forming a hand-in-hand form). The shaft transmission assembly is composed of an end shaft, an off-axis orthogonal shaft body, and a hinge rod. The end shaft is a connecting member that is rigidly connected to the power shaft and has a rotating shaft or shaft hole perpendicular to the power shaft. The off-axis orthogonal shaft body is an intermediate body of two sets of rotating shafts (or off-axis rotating shafts) with orthogonal axes or an off-axis slideway of the shaft hole. The hinge rod is a component that connects two orthogonal shaft bodies through a hinge shaft or an off-axis hinge shaft (or a component of orthogonal shaft bodies with non-intersecting axes). Working principle: Since both of the two orthogonal shafts have the pointing function of a universal joint, any of the two shafts can be coordinated and completed through the intermediate body. The inserted shaft transmission assembly is a general one in the industry, including general ones such as a cross shaft, a constant velocity joint, and a connecting rod shaft transmission assembly, etc.

[0028] It is characterized in that multiple worm components can be used in series. The worm shaft can be extended and connected to one end shaft of the shaft transmission assembly, and the other shaft end is then connected to the worm shaft of the next worm, forming a hand-in-hand form. The inserted shaft transmission assembly includes general ones such as a cross shaft, a constant velocity joint, and a connecting rod shaft transmission assembly, or is composed of an end shaft, an off-axis cross shaft body, and a sliding piece. The end shaft is a connecting member that is rigidly connected to the power shaft and has a rotating shaft or shaft hole perpendicular to the power shaft. The off-axis cross shaft body is an intermediate body of two sets of rotating shafts with orthogonal axes or an off-axis slideway of the shaft hole. The two ends of the sliding piece are components that connect the cross shaft body through a hinge shaft or an off-axis hinge shaft or components of cross shaft bodies with non-intersecting axes.

[0029] Furthermore, the ball guide tube is a selective component and does not have to be adopted. There is a return channel that directly penetrates the two end faces of the worm and is processed inside the worm, and the balls at the end of the spiral groove can be directly connected.

[0030] The technical progress of the present invention: completely overcomes the working principle defects of the gear system and the high-friction worm gear system; provides a rotational power transmission module that can be comparable to the ball screw for linear displacement, and at the same time has the advantages of high precision, high rigidity (transmission torque), and high service life. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0031] The following further describes the present invention with reference to the preferred embodiments of the present invention in conjunction with the accompanying drawings:

[0032] Figure 1 Schematic diagram of the high-rigidity precision ball worm gear structure.

[0033] Figure 2Explosion schematic diagram of high-rigidity precision ball worm and worm wheel.

[0034] Figure 3 Perspective view of high-rigidity precision ball worm and worm wheel

[0035] Figure 4 Front schematic diagram of high-rigidity precision ball worm and worm wheel

[0036] Figure 5 Front and bottom-up views of high-rigidity precision ball worm and worm wheel

[0037] Figure 6 Schematic diagram of the structure of the shaft transmission component

[0038] Description of the reference numerals in the figure:

[0039] 1 Worm wheel

[0040] 2 Helical groove

[0041] 3 Worm wheel shaft (power output shaft)

[0042] 16 Worm wheel disc <�

[0043] 17 Groove bottom

[0044] 4 Worm

[0045] 5 Spiral groove

[0046] 6 Ball guide tube

[0047] 7 Ball return hole

[0048] 8 Worm shaft (power input shaft)

[0049] 18 Return channel

[0050] 25 Spiral body

[0051] 9 Support component

[0052] 10 Constraint cover (or opposed worm wheel layout)

[0053] 11 Connecting structure

[0054] 12 Worm wheel shaft hole

[0055] 13 Worm shaft hole

[0056] 14 Steel ball

[0057] 19 Steel ball line

[0058] 20 Shaft transmission component

[0059] 21 End shaft

[0060] 22 Hinge rod

[0061] It should be noted that in the translation, "<�

[0043] " in the original text seems to be an incorrect symbol. It is retained as is in the translation. If it is an error, please check and correct it in the original content.23 (with off-axis) orthogonal shaft body

[0062] 30 Ring-notch bulge

[0063] 31 Ring-notch groove

[0064] 24 Motor

[0065] 25 Axis 1

[0066] 26 Axis 2

[0067] 27 Axis 3 [Specific implementation manner]

[0068] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 shown:

[0069] The high-rigidity precision ball worm and worm gear consists of three major components: including the worm gear component 1, the worm component 4 and the support component 9; the structural details of each component are: the worm gear component 1 is composed of the worm gear disk 16 and the worm gear shaft (power output shaft) 3 rigidly connected thereto. At the peripheral cylindrical surface position of the worm gear disk 16, a groove with a semi-circular cross-section is machined, and this groove surrounds the entire circumference of the worm gear disk 16. As shown by the groove bottom 17 in Figure 3 , a closed ring groove is formed, and the circumferential lines of the two circumferential surfaces at the two ends of the worm gear 2 are equivalent to the two banks of the closed ring groove; the inclined groove 2 is a group of equally spaced non-intersecting grooves with a semi-circular cross-section, and the grooves are arranged in the groove with a semi-circular cross-section at the periphery of the worm gear disk 16, straddling (diagonally rather than straight across) the "two banks" of the groove with a semi-circular cross-section; the worm (pair) component 4 is a spiral body 25 object with a spiral groove 5, and the spiral groove 5 surrounds the "saddle-shaped" circumferential surface of the spiral body 25; and the ball return hole 7 or the through groove at the end of the spiral groove 5 is aligned with one end of the ball guide tube 6; the worm shaft (power input shaft) 8 and the worm gear shaft (power output shaft) 3 are both constrained by the worm shaft hole 13 and the worm gear shaft hole 12 of the support component 9 and freely rotate under the support of the bearing 15; the constraint cover body 10 of the support component 9 covers the exposed semi-peripheral surface of the worm (pair) component 4, restricting the steel balls 14 from disengaging from the spiral groove 5. When the spiral groove 5 and the return channel 18 are filled with steel balls, a closed steel ball line array 19 is formed; in the opposed worm gear layout, there are two worm gears docking with one worm (pair) component, which naturally prevents the steel balls from slipping out.

[0070] Figure 5In the high-rigidity precision ball worm and worm gear system, the working principle is as follows: First, the connecting structure 11 of the supporting component 9 connects the worm shaft hole 13 and the worm gear shaft hole 12 into a whole, enabling the worm and worm gear to form a driving relationship; under the constraint and cooperation of all components, a closed ball channel will be formed: It consists of a spiral channel section (the spiral groove 5 of the worm, the inclined groove 2 of the worm gear, and the constraint cover 10 of the supporting component 9), and a return channel 18. The connection of the closed channel is achieved through the docking of 2 ball return holes 7 or slots at the end of the spiral groove 5; the ball guide 6 can be replaced by the bent holes directly machined at both ends of the worm (pair) component 4. When the power torque causes the worm 4 to rotate, it pushes the balls 14 to move spirally along the spiral groove 5. Due to the pushing effect between the balls, the worm gear is further pushed to rotate, and all the balls in the closed ball line produce following queuing displacement: That is, the driving motor 24 drives the worm shaft (power input shaft) 8 to rotate, and then drives the next worm through the shaft transmission component 20. Multiple worms can be continuously driven in series in a hand-in-hand manner; the load-bearing capacity of the worm and worm gear for the transmitted torque is increased.

[0071] As Figure 6 shown:

[0072] They are respectively the front view, perspective view, and exploded view of the shaft transmission component.

[0073] The shaft transmission component 20 is composed of an end shaft 21, an off-axis orthogonal shaft body 23 with an off-axis, and a hinge rod 22; the end shaft 21 is a connecting piece that is rigidly connected to the power shaft and has a connecting part perpendicular to the rotating shaft or shaft hole of the power shaft. The off-axis orthogonal shaft body 23 is an intermediate body of two sets of rotating shafts (or off-axis rotating shafts) or shaft holes with off-axis slideways whose axes are orthogonal. The hinge rod 22 is a component that connects 2 orthogonal shaft bodies through a hinge shaft or off-axis hinge shaft (or an orthogonal shaft body component whose axes do not intersect); the working principle: Since both of the two orthogonal shafts have the pointing function of a universal joint, any of the two shafts can be coordinated and completed through the intermediate body. The ring-notch protrusion 30 of the hinge rod 22 and the ring-notch groove 31 on the orthogonal shaft body 23 are hinged off-axis, equivalent to rotating around the axis 2 26, forming a cross-shaft assembly with the axis 3 27; the axis 1 25 is respectively connected by the end shaft 21 to the two shafts that need to transmit torque.

Claims

1. A high-rigidity precision ball worm gear, comprising a worm wheel, a worm, and a supporting component. The worm wheel comprises a worm wheel disc and a worm wheel shaft, while the worm comprises a worm shaft and a spiral body. The supporting component is provided with a worm shaft hole and a worm wheel shaft hole, which are used to mount and constrain the worm and worm wheel shafts, allowing them to rotate freely under the support of bearings. The supporting component connects the worm shaft hole and the worm wheel shaft hole into a single unit, thereby forming a driving relationship between the worm wheel and the worm. Features: A semicircular groove is machined on the cylindrical surface of the worm wheel disc. This groove is a closed ring groove structure that surrounds the entire cylindrical surface of the worm wheel disc. A series of equally spaced, evenly arranged, non-intersecting oblique grooves are machined on the bottom surface of the closed ring groove. These oblique grooves have a semicircular cross-section. The spiral body of the worm is a cylindrical object with a spiral groove on the side. The spiral groove surrounds the cylindrical surface of the worm pair. Ball return holes or through grooves are opened at both ends of the spiral groove to align with the orifice of the ball guide tube. The other end of the orifice of the ball guide tube aligns with the return channel machined inside the worm and passes through the two end faces of the worm. The part of the constraint cover body fastened to the supporting component covers the exposed half of the worm component, and the inner surface of the constraint cover body just contacts the steel balls with a certain gap, so that the steel balls do not leave the spiral groove but can slide freely; when the entire closed path composed of the spiral groove, ball guide tube and return channel is filled with steel balls, a closed arrangement of steel balls is formed.

2. The high-rigidity precision ball worm and worm wheel according to claim 1, wherein: Multiple worm components can be used in series, and their worm shafts can be extended and connected to one end shaft of the shaft transmission assembly, while the other shaft end is connected to the worm shaft of the next worm, forming a hand-in-hand form; and the inserted shaft transmission assembly includes a universal, cross shaft, ball cage, connecting rod shaft transmission assembly, or is composed of an end shaft, a cross shaft body with an off-axis and a slide; the end shaft is a connector rigidly connected to the power shaft and has a rotating shaft or shaft hole perpendicular to the power shaft, the cross shaft body with an off-axis is an intermediate body of two groups of rotating shafts or shaft hole off-axis slides with orthogonal axes, and the two ends of the slide are components of the cross shaft body connected by hinges or off-axis hinges or cross shaft body components with non-intersecting axes.

3. The high-rigidity precision ball worm and worm gear according to claim 1, wherein: The spiral body of the worm is provided with a spiral groove on one side. The matching thread of the spiral groove can be single-start or multi-start, and the corresponding return channel is also increased to the number of multi-start.

4. The high-rigidity precision ball worm and worm gear according to claim 1, characterized in that: The ball guide tube of the worm can directly connect to the ball at the end of the spiral channel by directly machining a return channel that passes through the two end faces of the worm in the curved channel inside the worm, thereby omitting the ball guide tube component.

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