Folding-shaft multi-worm middle-pushing type high-precision worm gear rotary table

Abstract

The utility model discloses a folding-shaft multi-worm middle-pushing type high-precision worm gear rotary table, and belongs to the field of machinery. Comprising three parts: a worm gear, a worm and a folding shaft or a bevel gear; a folding shaft hole or a bevel gear used for being in sliding fit with the folding shaft part is machined at the end of the worm, the axis of the folding shaft hole is parallel to the axis of the inserted folding shaft part, and the bevel gear and the worm are coaxial in position. According to the basic assembly relation, the shell and the supporting component are used for installing and restraining the steel ball ring groove and the worm bearing of the worm gear; the worm shaft hole and the worm gear shaft hole are connected into a whole through the supporting component. The end part bearing is a conventional bearing and directly restrains the end part of the worm, or the semi-cylindrical middle part retaining bearing is equivalent to a toothless cylindrical surface matched with the middle part of a bearing bush; the bending angle of the bending part of the bending shaft is 90-180 degrees, the straight shaft sections of the two shaft sections are inserted into the bending shaft hole in the end of the bending shaft and are in sliding fit with the bending shaft hole, and the bending shaft can be widely used as a power rotating table of a machine tool.

Description

[TECHNICAL FIELD]

[0001] The present application belongs to the technical field of machinery, and more particularly to a worm gear reducer rotary table with multiple worm gears and more tooth contact to improve running accuracy and increase rigidity. [BACKGROUND]

[0002] Worm gear structures are often used to transmit motion and power between two intersecting shafts. The worm gear and the worm are equivalent to the gear and the rack in the middle plane, and the worm is similar in shape to the 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 addendum coefficient (take 0.2). Among them, the module m and the pressure angle refer to the module and the pressure angle of the worm shaft surface, that is, the module and the pressure angle of the worm wheel end surface, and both are standard values; the worm diameter coefficient q is the ratio of the worm division circle diameter to its module m.

[0004] Running characteristics: a large transmission ratio can be obtained, and the compactness of the intersecting shaft helical gear mechanism is tight. 2. The line contact between the two meshing tooth surfaces is much higher than that of the intersecting shaft helical gear mechanism. 3. Worm transmission is equivalent to spiral transmission, which is multi-tooth meshing transmission, 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, which can realize reverse self-locking, that is, only the worm can drive the worm wheel, but the worm wheel cannot drive the worm. The reverse self-locking property of the self-locking worm mechanism used in hoisting machinery can play a safety protection role. 5. The transmission efficiency is low and the wear is serious. When the worm gear is engaged

[0005] 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 worm axial force is large, the relative sliding speed is large, which makes the tooth surface wear seriously and the heat is serious. In order to dissipate heat and reduce wear, expensive materials with good friction reduction and wear resistance and good lubrication devices are often used, so the cost is high.

[0006] Advantages and disadvantages:

[0007] Worm gear transmission (including machine tool rotary table) and other forms of gear transmission have the following advantages and disadvantages.

[0008] Advantages:

[0009] * Single-stage speed ratio is large:

[0010] The single-stage speed ratio of the spur gear drive and the bevel gear drive is generally about 1 / 10 at most, while the worm and gear drive with a speed ratio of 1 / 70 to 1 / 100 is easily manufactured. Thus, the worm and gear drive reducer can achieve a large speed ratio with a small size. In many cases, the worm and gear reducer with a speed ratio of 1 / 5, 1 / 25, 1 / 70, or 1 / 150 is compared with the helical gear reducer. When the transmission power is 30 horsepower and the input shaft speed is 1200 rpm.

[0011] *Low noise and small vibration: The spur gear and the bevel gear are mainly in rolling contact when they are engaged, while the worm is mainly in sliding contact. Thus, there are fewer factors that cause noise and vibration. For this reason, the worm and gear reducer is preferred for driving escalators, elevators, moving sidewalks, and machines for preventing pollution in recent years.

[0012] *The shafts of the worm and gear reducer can be arranged vertically without intersecting each other: The arrangement of the worm shaft and the worm wheel shaft can sometimes be made to save the installation area of the prime mover and the driven machine and to be convenient and reasonable.

[0013] *Prevention of reverse rotation: When the lead angle of the worm is smaller than the friction angle, the worm cannot theoretically drive the worm wheel, that is, a self-locking worm drive can be designed. However, in practice, the friction coefficient of the tooth surface changes from the static friction coefficient to the dynamic friction coefficient due to vibration and other reasons. Thus, the worm sometimes slowly rotates, and it is difficult to achieve complete self-locking.

[0014] Disadvantages: The existing worm and gear mechanism is a general high-friction tooth contact operation mode. In addition to low transmission efficiency, there is a tooth gap. The contact area of the contact line between the teeth is also very limited.

[0015] *Low efficiency: Compared with other forms of gear drive, the worm and gear drive has a large tooth surface friction loss when transmitting power, and the efficiency is low. At present, due to the improvement of the manufacturing method, the efficiency close to the theoretical value can be achieved. In some cases, the efficiency of the worm and gear drive is 98% when the speed ratio is 1 / 5 and the worm speed is 180 rpm. However, when the speed ratio is 1 / 70 and the worm speed is 200 rpm, the efficiency is about 60%.

[0016] *Easy tooth surface adhesion: The involute tooth profile cylindrical gear, if the tooth surface bears a load, the tooth contact state changes in a good direction due to the deformation of each part, while the tooth contact state of the worm and gear drive changes in a bad direction, that is, the direction of tooth surface oil film rupture. Thus, the deformation amount should be estimated to adjust the tooth contact state and the bearing gap during assembly. Careful running-in operation must also be performed.

[0017] Life and cost problem: the worm and worm gear transmission adopts copper alloy material, because the special gear cutting machine tool is generally used, the gear cutting processing efficiency is low, and the tooth surface is manually finished, which is very time-consuming, [SUMMARY]

[0018] Objectives of the present application:

[0019] Overcome the shortcomings of the prior art, improve the larger area contact between the worm and the worm, improve the low transmission efficiency and the transmission stiffness, and the service life is limited and other unfavorable factors.

[0020] Features of the present application:

[0021] The first feature is to greatly increase the area and number of tooth contact, which greatly overcomes the inherent defect of limited tooth contact area; under the condition of greatly reducing the value of tooth contact pressure, the service life will be greatly increased. Another great progress is to creatively give two worm shaft transmission mechanisms, which can realize compact and extremely small torque transmission of two connecting rod shafts.

[0022] Key technology of the present application:

[0023] Create a folding shaft coupling condition, compactly couple multiple worms to achieve large torque output.

[0024] Specific invention content:

[0025] The folding shaft multi-worm push type high-precision worm gear rotary table (also known as a speed reducer) includes three parts: a worm, a worm, and a folding shaft (a coupling part: or a bevel gear); the structure of the worm includes a worm disc (a power output disc) and a worm helical tooth, and a part for installing a bearing; the structure of the worm includes a worm shaft and a spiral tooth, and a folding shaft hole is machined at the end of the worm for mutual sliding fit with the folding shaft shaft part, the axis of the folding shaft hole and the axis of the inserted folding shaft shaft part are parallel to each other; the housing includes an upper cover, a lower cover, and an output shaft hole; the support part includes an end bearing or a middle retaining bearing; the folding shaft as a coupling transmission part includes a folding part and a shaft part.

[0026] The detailed structure of each part is as follows: the worm includes a worm disc (a power output shaft part), a worm helical tooth, and a worm steel ball ring groove; the side surface of the worm (secondary) has a spiral tooth, which can be a continuous tooth shape; or it can be toothless in the middle, and the two ends of the worm have a spiral tooth spindle structure; in the case of toothless in the middle of the worm, a middle retaining bearing is needed to make the middle shaft of the worm have a larger diameter space and have larger mechanical strength.

[0027] Assembly relationship: the shell and the supporting part are used to install and constrain the steel ball ring groove and the worm bearing; since the supporting part connects the worm shaft hole and the worm wheel shaft hole into a whole, and the worm wheel and the worm are freely rotated under the support and constraint of the bearing, the driving relationship between the worm wheel and the worm is formed. The end bearing is a common bearing, and the middle retaining bearing is a semi-cylindrical (equivalent to a bearing shell) bearing, so as to keep the diameter of the middle part as much as possible (the strength requirement), and a common bearing can also be used if the strength is not required.

[0028] The structure of the multi-worm is that the worm shaft is extended, the end shafts of two worms are connected by using a shaft coupling part to form a hand-in-hand shaft coupling form; the most important shaft coupling component is a folding shaft; the folding shaft is a straight shaft bent at a certain angle, and the bending angle of the folding part is 90-180 degrees; the straight shaft sections of the two shaft parts are inserted into the folding shaft holes at the ends of the folding shaft in a sliding fit relationship; the folding shaft can be 1-20, and is eccentrically installed; the structure of the multi-worm has good transmission stiffness, good transmission linearity and good transmission stiffness; since the contact geometric linearity is long enough, it also has good transmission accuracy (using a bevel gear for transmission has a great disadvantage: due to the small contact area, the transmission stiffness is limited, and the wear is intensified, so that the accuracy cannot be continuously guaranteed).

[0029] In addition, in order to increase the thrust, the matching screw and groove of the worm and the worm wheel for containing the steel ball can be single-headed or multi-headed, and the number of corresponding return channels is also increased to the number of multi-headers; the reason for considering multi-headers is that, under the mathematical geometric relationship of the relative uniform rotation of the closed ring groove of the worm spiral body and the worm wheel disc part, only the steel balls at the local groove and spiral groove can meet the close contact relationship of operation, and the gap is not too large, so multiple worm shafts are needed to meet the demand of large load torque.

[0030] Working principle of the folding shaft multi-worm middle thrust type high-precision worm wheel turntable:

[0031] The present application is the same as the conventional worm and worm gear transmission; the difference is that it contains a multi-worm linkage mode and no teeth in the middle of the worm to obtain a large diameter of the middle of the worm as a shaft part (large mechanical strength); the mathematical principle of the folding shaft coupling is that when the folding shaft holes of two adjacent worms are inserted into the shaft parts of the folding shaft, the two worms are coupled by the folding shaft; since the folding shaft hole and the folding shaft are in a sliding fit relationship, the two fixed shaft rotating worms can only respond and cooperate with the same angular velocity and synchronization under the mathematical and physical conditions; thus, a more favorable shaft coupling state than bevel gear transmission is formed.

[0032] Further, the shaft coupling transmission of the multi-worm can also directly use two bevel gears fixed at the ends of the worm shaft for transmission, the axis of the folding shaft hole and the axis of the inserted folding shaft shaft part are parallel to each other, and the position relationship between the bevel gear and the worm is coaxial.

[0033] Further: the side of the worm is provided with helical teeth, which can be continuous tooth profile; or can be toothless in the middle, and the two ends of the worm are provided with helical teeth in the spindle-shaped structure;

[0034] The technical progress of the present application: completely overcome the defect of insufficient stiffness of worm gear system; give a kind of transmission module of shaft type multi-worm worm gear, which has the advantages of high precision, high stiffness (transmission torque) and high life. [DETAILED DESCRIPTION]

[0035] The preferred embodiments of the present application will be further described below in conjunction with the accompanying drawings of the present application:

[0036] [ Figure 1 ]Overall schematic diagram of the fold-axis multi-worm push type high-precision worm gear rotary table.

[0037] [ Figure 2 ]Cross-sectional view of the fold-axis multi-worm push type high-precision worm gear rotary table.

[0038] [ Figure 3}Exploded view of the fold-axis multi-worm push type high-precision worm gear rotary table.

[0039] [ Figure 4}Exploded view of the core components of the rotary table.

[0040] [ Figure 5 ]Schematic diagram of the fold-axis shaft coupling transmission of the worm.

[0041] [ Figure 6 ]Schematic diagram of the transmission of bevel gear

[0042] Explanation of figure numbers:

[0043] 1 worm gear

[0044] 1-1 worm gear disc (power output disc)

[0045] 1-2 worm gear helical tooth

[0046] 1-3 steel ball ring groove

[0047] 1-4 worm gear axis

[0048] 2 worm

[0049] 2-1 helical tooth

[0050] 2-2 worm shaft (power input shaft)

[0051] 2-3 fold-axis shaft hole

[0052] 2-4 worm shaft axis

[0053] 2-5 middle shaft position

[0054] 3. Shell and Support Components

[0055] 3-1 Upper cover body

[0056] 3-2 lower cover body

[0057] 3-3 Output shaft hole

[0058] 3-4 end bearings

[0059] 3-5 Middle Retaining Bearing

[0060] 3-6 bearing ring

[0061] 3-7 Adjustment and fixing holes

[0062] 3-8 bearing ring internal thread

[0063] 4-fold shaft (coupling transmission component)

[0064] 4-1 fold

[0065] 4-2 Shaft

[0066] 4-3 Folded Shaft Axis

[0067] 5 steel balls

[0068] 6-bevel gear

[0069] 7 axis lines

[0070] 8 worm gear extension shaft [Detailed Implementation]

[0071] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown:

[0072] Figure 1 This is an overall schematic diagram of a multi-worm gear push-type high-precision worm gear rotary table with a folded shaft, including three main components: worm gear (1), worm (pair) (2), and folded shaft (4); the worm gear (1) is constructed including a worm gear disc (1-1) (often used as a power output disc) and worm gear helical teeth (1-2); the worm (2) is constructed including a worm shaft (2-2), a central shaft position (2-5), and helical teeth (2-1), and the end of the worm (2) is machined with a folded shaft hole (2-3) for sliding cooperation with the folded shaft shaft part (4-2) of the folded shaft (4), a folded part (4-1), and a shaft part (4-2) connected to the folded part; the housing and supporting components include an upper cover (3-1), a lower cover (3-2), an output shaft hole (3-3); an end bearing (3-4) and a central retaining bearing (3-5), and an adjustment and fixing hole (3-7).

[0073] Assembly relationship: from Figure 2 , Figure 3 , Figure 4 , Figure 5 It can be seen that the shell and support components are used to install and constrain the middle bearing (3-5) of the worm ball ring groove (1-3) of the worm (1), the bearing ring (3-6) (and the bearing ring inner thread (3-8), the upper and lower clamping strikes cooperate with each other, and the clamped steel ball (5) (the steel balls are arranged in a ring shape, just between the upper cover and the lower cover and the worm ball ring groove) to maintain the worm around its worm axis (1-4) The fixed rotation of the shaft; and the upper cover (3-1) and the lower cover (3-2) as a support component connects the worm shaft hole and the worm shaft hole into a whole, and the worm (1) and the worm (2) are free to rotate under the support and constraint of the bearing (Independent bearing or steel ball (5) placed in the processed steel ball ring groove on the corresponding steel ball ring groove to form a self-arranged bearing can be used), so that the worm (1) and the worm (2) form a vertical driving relationship. The worm bearing is also diversified (positioned at the end, middle or semi-enclosed bearing), and the outermost worm point end bearing (3-4) is a conventional bearing or a self-arranged bearing, and the middle bearing (3-5) is a semi-cylindrical (equivalent to a bearing) bearing mode to maintain the diameter of the middle part as much as possible (strength requirement), if not required to maintain strength, a conventional bearing can also be used; The connecting shaft of the multi-worm is completed by using the folding shaft (2) as a transmission component, the folding shaft shaft part (4-2) of the folding shaft (4) is inserted into the folding shaft hole (2-3) at the end of the worm, and is in sliding fit; and the folding shaft axis (4-3) is parallel to the inserted worm axis (2-4).

[0074] The basic working principle of the folding shaft multi-worm middle push type high-precision worm rotary table:

[0075] The basic working principle is the same as that of the conventional worm and worm gear transmission, the difference lies in the working mode of the multi-worm linkage; in order to obtain large mechanical strength and rigidity, the folding shaft connecting shaft structure is one of the most effective operation modes; the mathematical principle of the folding shaft is that when the folding shaft hole (2-3) of the two adjacent worms (2) is inserted by the folding shaft shaft part (4-2), the two connected shafts of the fixed rotation worm are limited to have the same rotational speed and angular displacement; At the same time, the folding shaft hole (2-3) and the folding shaft shaft part (4-2) are in sliding fit, and the motion relationship is that the two fixed rotation worms can only have the same angular velocity and synchronous response and cooperation under the mathematical and physical conditions; Thus, a more favorable connecting shaft state is formed than the bevel gear transmission.

[0076] As shown in Figure 6}:

[0077] The worm gear (6) installed on the shaft end of the worm extension shaft (8) can also meet the torque transmission of the non-parallel worm shafts (7); obviously, the worm gear transmission requires a zero (small) gap transmission mode, so that the two gears need to be in close contact, and the tooth contact point has a large contact force, which is very demanding on the face type, accuracy and strength of the gear.

Claims

1. A high-precision worm wheel turntable of a fold shaft multi-worm push type, comprising three main components: a worm wheel, a worm, and a fold shaft or bevel gear; wherein the structure of the worm wheel comprises a worm wheel disc and worm wheel helical teeth; the structure of the worm comprises a worm shaft and helical teeth, and a fold shaft hole or bevel gear is processed at the end of the worm for mutual sliding fit with the fold shaft shaft part; the axis of the fold shaft hole is parallel to the axis of the inserted fold shaft shaft part, and the position relationship between the bevel gear and the worm is coaxial; in addition, the structure shell comprises an upper cover body, a lower cover body, and an output shaft hole. Supporting part for keeping worm running includes end bearing or middle retaining bearing, and folded shaft as alternative coupling part of bevel gear, which is configured with folded part and shaft part, and has basic assembly relationship that shell and supporting part are used to install and constrain steel ball ring groove of worm wheel and worm bearing, and worm wheel and worm are connected as a whole by supporting part, and are freely rotated under the support and constraint of bearing, so that driving relationship is formed between worm wheel and worm, end bearing is common bearing which directly constrains end of worm, or middle retaining bearing is bush which directly constrains toothless cylindrical surface of middle part of worm, folded shaft is a straight shaft which is folded at an angle, and the folding angle of folded part is 90-180 degrees, and straight shaft segments of two shaft parts are inserted into folded shaft hole of end part of folded shaft and are in sliding fit relationship, and the number of folded shafts can be 1-20, and the folded shafts are eccentrically installed. The features are as follows: Multi-worm structure is adopted, the coupling part of multi-worm is folded shaft or bevel gear, 1-20 folded shaft holes which are parallel to worm shaft are processed on end part of worm, and are matched with inserted folded shafts to couple two adjacent worms, and hand-in-hand coupling form is formed, or coaxial bevel gears for mutual driving are processed on end part of worm.

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