Gap-adjustable worm and gear type speed reducer

Abstract

The invention provides a clearance-adjustable worm and gear type speed reducer. The clearance-adjustable worm and gear type speed reducer comprises a box body, the worm wheel assembly comprises a worm wheel, an output shaft coaxially fixed with the worm wheel, and a first bearing seat and a second bearing seat which are respectively arranged on two sides of the worm wheel and support two ends of the output shaft; the worm gear assembly is detachably installed on the box body through the first bearing seat and the second bearing seat, and a whole is formed after installation. The worm is rotatably supported on the box body through a bearing assembly and is meshed with the worm gear; the first adjusting mechanism is arranged between the first bearing seat and / or the second bearing seat and the box body, and is used for driving the worm gear assembly as a whole to perform position fine adjustment relative to the box body in the radial direction of the output shaft; and the second adjusting mechanism is arranged on the box body, is connected with one end of the worm and is used for independently adjusting the axial mounting position of the worm. After being installed, the worm gear assembly serves as a whole to be subjected to radial fine adjustment and cooperates with worm axial adjustment, and therefore the bidirectional transmission gap is compensated conveniently and accurately.

Description

Technical Field

[0001] This invention relates to the field of mechanical transmission technology, and specifically to an adjustable clearance worm gear reducer. Background Technology

[0002] Worm gear reducers are widely used power transmission devices. The meshing quality of the core transmission pair, the worm gear and the worm, directly determines the smoothness, accuracy, and lifespan of the transmission. During long-term operation, normal wear of the meshing surfaces leads to an increase in the backlash between them, and the worm may also experience axial movement. These increased clearances can cause problems such as transmission shock, increased noise, decreased accuracy, and even failure.

[0003] To compensate for wear clearances, traditional speed reducers typically employ a split-type adjustment method. For example, adjusting worm gear backlash often requires loosening the bearing housing, moving the worm gear shaft or shims. This process may involve aligning and re-fixing multiple parts, making it cumbersome and prone to compromising original assembly precision. Adjusting worm axial backlash requires adjusting the preload of its end bearing. These adjustment methods have significant drawbacks: the adjustment process usually requires varying degrees of disassembly or displacement of assembled components, making it impossible to achieve "integral" fine-tuning of the transmission assembly. This not only increases maintenance difficulty and time but also makes it difficult to ensure overall performance after adjustment due to the disruption of the initial optimized assembly state.

[0004] Therefore, existing technologies lack a worm gear reducer structure that can conveniently, independently, and accurately compensate for radial meshing clearance and axial runout clearance without disassembling the core transmission components. This results in poor equipment maintainability and uneconomical long-term operation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes an adjustable clearance worm gear reducer. After installation, the worm gear assembly is radially fine-tuned as a whole and works in conjunction with the axial adjustment of the worm, thereby conveniently and accurately compensating for transmission clearance in both directions.

[0006] The technical solution of this invention is implemented as follows: An adjustable clearance worm gear reducer includes a housing; The worm gear assembly includes a worm gear, an output shaft fixed coaxially with the worm gear, and a first bearing seat and a second bearing seat respectively disposed on both sides of the worm gear and supporting the two ends of the output shaft; The worm gear assembly is detachably mounted on the housing via a first bearing seat and a second bearing seat, and forms a whole after installation. This whole is a transmission module that can maintain the relative assembly relationship of the internal components. The worm gear is rotatably supported on the housing by a bearing assembly and meshes with the worm wheel; A first adjusting mechanism is arranged between the first bearing seat and the box body and between the second bearing seat and the box body, and is used to drive the worm gear assembly as a whole to be finely adjusted in position relative to the box body in the radial direction of the output shaft, so as to compensate for the meshing side clearance between the worm gear and the worm; A second adjusting mechanism is arranged on the box body and is connected with one end of the worm, and is used to independently adjust the axial installation position of the worm, so as to compensate for the axial play clearance of the worm.

[0007] Preferably, the first bearing seat is provided with a power output shaft hole through which the output shaft penetrates; the second bearing seat is provided with a bearing cavity on the side facing the worm gear, which is used to accommodate a bearing to support the end of the output shaft; and the first bearing seat and the second bearing seat cover and close the opposite installation openings on the box body after installation.

[0008] Preferably, the first adjusting mechanism comprises an adjusting hole formed on the first bearing seat and / or the second bearing seat, and a fastener penetrating through the adjusting hole and locking the corresponding bearing seat to the box body; the extending direction of the adjusting hole is parallel to the radial direction of the output shaft, and is used to adjust the installation position of the bearing assembly of one end of the worm.

[0009] Preferably, the adjusting hole is a waist-shaped hole and is provided with at least two on a single bearing seat and is symmetrically arranged around the center of the output shaft; the width of the adjusting hole is matched with the width of the installation hole of the box body.

[0010] Preferably, the second adjusting mechanism is an axial adjusting assembly arranged at one end of the worm; the axial adjusting assembly comprises an adjusting element which is movable in the axial direction of the worm; and the adjusting end of the adjusting element abuts against the bearing assembly of one end of the worm.

[0011] Preferably, the axial adjusting assembly further comprises an adjusting end cover fixed to the box body; and the adjusting element is an adjusting bolt which is threadedly connected to the adjusting end cover.

[0012] Preferably, the axial adjusting assembly further comprises a spacer sleeve arranged between the adjusting bolt and the bearing assembly of the worm; the end of the adjusting bolt abuts against the spacer sleeve; and the spacer sleeve is axially moved by screwing the adjusting bolt.

[0013] Preferably, the spacer sleeve is a cylindrical structure; the bottom end of the spacer sleeve abuts against the end of the adjusting bolt; and the top end of the spacer sleeve abuts against the outer ring end face of the bearing assembly.

[0014] Preferably, the bearing assembly of the worm is a pair of conical roller bearings.

[0015] Preferably, a sealing element is provided between the first bearing housing and the housing, between the second bearing housing and the housing, or at the support structure of the bearing assembly of the worm gear.

[0016] Compared with the prior art, the present invention has the following advantages: This solution employs a unique structural design, making the worm gear assembly (including the worm gear, output shaft, and bearing housings at both ends) a rigid, operable unit after installation into the housing. A first adjustment mechanism (such as the oblong holes and fasteners on the bearing housings) acts on this installed unit, directly driving the entire worm gear assembly to move smoothly and slightly radially along the output shaft, thereby precisely adjusting and compensating for the meshing backlash between the worm gear and the worm. Simultaneously, an independent second adjustment mechanism (such as the combination of adjusting bolts, spacers, and tapered roller bearings) acts on the worm end, allowing for individual adjustment of its axial position to eliminate backlash. Both adjustments are performed under normal conditions after the equipment is assembled, without disassembling or breaking down any internal connections of the worm gear assembly, nor damaging the basic support of the worm. This solution fundamentally overcomes the inherent defects of prior art, which requires "split-type" disassembly and reassembly of transmission components for backlash adjustment, resulting in cumbersome operations, time-consuming processes, and difficulty in maintaining the original assembly precision. Its beneficial effects are: it enables convenient, independent, in-situ and high-precision compensation of the core clearance of the transmission system, greatly simplifies maintenance operations, shortens maintenance time, and reliably maintains the stability and accuracy of the transmission chain, significantly improving the maintainability, service life and long-term economic efficiency of the equipment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a side sectional view of an adjustable clearance worm gear reducer according to the present invention; Figure 2 This is a half-sectional view of the front of an adjustable clearance worm gear reducer according to the present invention. Figure reference numerals: 1-Box body; 101-Mounting opening; 2-Worm gear assembly; 201-Worm gear; 202-Output shaft; 203-First bearing seat; 2031-Power output shaft hole; 204-Second bearing seat; 2041-Bearing cavity; 3-Worm; 301-Bearing assembly; 4-First adjusting mechanism; 401-Adjusting hole; 402-Fastener; 5-Second adjusting mechanism; 501-Adjusting end cover; 502-Adjusting bolt; 503-Spacer. Detailed Implementation

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0020] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third", "fourth", and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] Referring to the drawings Figure 1 and the drawings Figure 2 The adjustable gap worm gear reducer provided by the present application mainly comprises a box body 1, a worm gear assembly 2, a worm 3, a first adjusting mechanism 4 and a second adjusting mechanism 5.

[0023] The box 1 as the basis and framework of the entire transmission device, usually made of high-strength gray cast iron (such as HT250) or cast steel as a whole, to ensure sufficient rigidity, shock absorption and dimensional stability. Its internal cavity is compact and sealed, to accommodate and protect all the core transmission components. The opposite two side walls of the box 1, through precision boring and milling, are respectively provided with a first installation opening and a second installation opening (identified as 101 in the drawings). The two openings are not only passages, but also have high requirements for aperture and shape accuracy. They form a gap fit with the installation boss of the first bearing seat 203 and the second bearing seat 204. The fit gap is carefully calculated to ensure that the bearing seat can be smoothly installed and positioned, and to provide necessary and controllable space for the subsequent overall radial adjustment of the worm gear assembly 2 (usually a single-sided gap in the range of 0.1-0.3mm). This is one of the physical foundations and prerequisites for realizing the subsequent "overall" stepless adjustment. In addition, the box 1 is also processed with two high-coaxial bearing installation holes (usually stepped holes) parallel to the output shaft axis direction, which are used to accurately support the two ends of the worm 3. The coaxiality error of the two holes is usually required to be controlled within 0.02mm to ensure smooth operation of the worm.

[0024] The worm gear assembly 2 is the core functional module of the application, and is the carrier for realizing the concept of "overall disassembly and overall adjustment". It is not a pre-solidified integral assembly, but a rigid functional whole combined by several key component parts, including the worm gear 201, the output shaft 202, the first bearing seat 203 and the second bearing seat 204, in the process of installation in the box body 1 and after that, through the constraint of the box body 1. The worm gear 201 is usually made of wear-resistant bronze (such as ZCuSn10P1), and the hub center is provided with a key groove. The output shaft 202 is made of high-quality alloy steel (such as 40Cr) and is quenched and tempered, and has high strength and toughness. The shaft section matched with the worm gear 201 is processed with a corresponding flat key groove. During assembly, a heavy flat key is used to realize the coaxial fixed connection of the worm gear 201 and the output shaft 202 without relative rotation, and the connection can transmit a large torque. The first bearing seat 203 is usually designed as a sleeve structure with a mounting flange and is made of cast iron or steel, and a stepped hole, which is a power output shaft hole 2031, is precisely processed in it. A first deep groove ball bearing (such as 6312) is press-fitted in the small hole diameter section with interference fit, the inner ring of the bearing is in transition fit with the front end journal of the output shaft 202, and is used to accurately support the front end (i.e. the power output end) of the output shaft 202 and mainly bear the radial load. The second bearing seat 204 is designed as a closed end cover structure, and a circular bearing cavity 2041 is turned or bored on the side facing the worm gear 201. A second deep groove ball bearing is also press-fitted in the cavity with interference fit, and is used to support the rear end journal of the output shaft 202. The axial positioning of the two bearings is realized by the shaft shoulder on the output shaft 202, the sleeve and the step in the bearing seat. This design integrates the two-point support structure of the output shaft 202 in two independent bearing seats, which is the key structure for subsequent overall adjustment.

[0025] One of the most creative features of the invention is the unique mounting coupling relationship between the worm gear assembly 2 and the housing 1, and the "adjustable body" nature that this relationship catalyzes. The detailed mounting procedure is as follows: First, the bearing-pressed worm gear 201 and output shaft 202 sub-components (the axial position can be fixed in advance with a temporary sleeve) are carefully hoisted or pushed into the cavity of the housing 1, roughly aligning the worm gear tooth part with the future worm position. Then, the second bearing seat 204 that has been installed with bearings is sent from the mounting opening 101 on one side of the housing, so that the rear end journal of the output shaft 202 is precisely inserted into the inner hole of the second deep groove ball bearing. Next, the first bearing seat 203 is sleeved onto the front end journal of the output shaft 202 from the other side of the housing. At this time, the key step comes: the operator uses multiple sets of high-strength inner hexagonal bolts (as fasteners) to pass through the connecting holes on the flanges of the first bearing seat 203 and the second bearing seat 204, and screws into the pre-made threaded holes on the housing 1. According to the diagonal order, the bolts are tightened step by step and evenly. When all the bolts are firmly locked by applying the specified torque, the first bearing seat 203, the housing 1 body and the second bearing seat 204 are rigidly connected into a stable frame by the huge clamping force generated by the bolts. The worm gear 201 and the output shaft 202, together with the bearings at their two ends, are completely "encapsulated" and clamped inside the rigid chamber formed by the three. At this point, these originally separate parts lose their freedom of relative movement with each other under the constraint of the housing 1, and functionally merge into a transmission unit module that can be regarded as a "rigid body" with internal relative position locking. This "whole" is dynamically formed after being mounted in the housing and tightened, which means that in any subsequent maintenance, as long as the connecting bolts are loosened, the entire module (including the worm gear, shaft, bearing and its seat) can be completely disassembled from the housing as a complete unit; Conversely, when adjusting, the force applied to this "whole" will be transmitted to the internal worm gear tooth surface without loss. The front end of the output shaft 202 protrudes from the power output shaft hole 2031 of the first bearing seat 203, which is usually machined with a keyway or thread for mounting a coupling, sprocket or direct drive work machine, constituting the power output end.

[0026] The worm 3 as a power input and primary reduction element, its two end support mode is crucial to the axial gap adjustment. Worm 3 is usually made of surface hardening steel (such as 20CrMnTi, carburizing quenching) to obtain hard tooth surface. Its two end journal is supported on the box 1 by a pair of tapered roller bearings (such as 30211 series). Tapered roller bearings can withstand large radial and axial load, and its axial clearance can be adjusted, is the basis for the realization of the worm axial precision adjustment. Specifically, the worm 3 one end (defined as the power input end) through the first pair of face to face or back to back arrangement of tapered roller bearings supported, the end journal extends out of the box 1, can be connected by a flat key input shaft coupling, accept motor and other prime mover power. In the box bearing hole outside this end, through the bolt fastening a first fixed end cover (not marked in the figure, can be called front end cover), the boss or matching adjustment washer group inside the end cover, for accurate determination of the axial position of the pair of bearing outer ring, so as to realize the basic positioning of this end. The other end of the worm 3 (defined as the axial adjustment end) is supported by the second pair of the same arrangement of tapered roller bearings. The middle of the worm 3 is processed with the helical tooth part matched with the worm wheel 201, and the two constitute the worm and worm wheel pair of space staggered shaft transmission, which has the characteristics of single stage transmission ratio, compact structure and reverse self locking.

[0027] The first adjusting mechanism 4 is a device specially designed to compensate for the increased radial meshing backlash of the worm and gear pair due to long-term meshing wear. Its core components are adjusting holes 401 opened on the flanges of the first bearing seat 203 and / or the second bearing seat 204, and high-strength fasteners 402 (such as grade 12.9 bolts) passing through these long holes. Preferably, the adjusting holes 401 are designed as waist-shaped holes with semicircular ends, with their length center lines strictly parallel to the radial direction of the output shaft 202, and this direction is precisely directed to the center of the axis of the worm 3. The width of the adjusting holes is matched with the width of the mounting holes of the box 1 to facilitate the connection by bolts, preventing deviation in the width direction. On the flanges of each bearing seat involved in the adjustment, at least two (usually four) such waist-shaped holes are arranged symmetrically around their axis to ensure uniform force during adjustment and prevent deviation. The adjustment principle and operation process are as follows: when the transmission noise increases or the return gap exceeds the standard, the maintenance personnel first use a torque wrench to loosen the fasteners 402 to a degree that can still maintain the basic position of the bearing seat. At this time, since the worm assembly 2 has become a rigid whole after installation, the operator only needs to use a copper rod to gently knock or use a jackscrew to slightly adjust the side of the bearing seat. The entire worm assembly 2 (including the internal worm, output shaft, and bearings) will act as a complete rigid body and smoothly and accurately translate along the trajectory defined by the waist-shaped holes 401 relative to the fixed box 1. This translation directly and proportionally changes the center distance between the worm 201 and the worm 3. A small decrease in the center distance will immediately and effectively eliminate the excessive meshing backlash. During the adjustment process, a dial gauge can be used to press against the output shaft or the side of the bearing seat to accurately read the movement (usually between 0.05-0.2mm). After adjusting to the ideal position, tighten the fasteners 402 to the specified torque in a diagonal step-by-step manner to lock the entire worm assembly 2 in the newly set optimal working position. To further prevent possible micro-creep under long-term vibration and impact load and ensure the permanent stability of the adjusted position, two pin holes can be drilled on the abutting end faces of the first bearing seat 203 and / or the second bearing seat 204 and the box 1 after fine adjustment and final tightening, and high-precision conical pins (not shown in the figure) are inserted for final positioning. The conical pins rely on their taper to achieve a gapless fit, providing absolute position retention beyond friction locking.

[0028] The second adjusting mechanism 5 is a completely independent subsystem, which is used to eliminate the axial play of the worm 3 due to bearing wear or initial pre-tightening force relaxation. It is integrated in the axial adjusting end of the worm 3. The mechanism is mainly composed of three components: adjusting end cover 501, adjusting bolt 502 and spacer sleeve 503. The adjusting end cover 501 is a cast or forged end cover, which is fixed on the box 1 by multiple circumferentially distributed bolts, and a precise threaded hole is processed in the center. The adjusting bolt 502 is usually a fine thread (such as M30x1.5) inner hexagonal bolt, which is screwed into the threaded hole of the adjusting end cover 501. The spacer sleeve 503 is a cylindrical part with precisely ground outer circle and end face, which is installed in the inner cavity of the adjusting end cover 501, with one end (bottom end) in contact with the plane of the screw-in end of the adjusting bolt 502, and the other end (top end) directly abutting the outer ring end face of the second pair of tapered roller bearings supporting the end of the worm. Its working principle is a classic axial pre-tightening adjustment: when the adjusting bolt 502 is screwed clockwise, the bolt pushes the spacer sleeve 503 to move inward, and the spacer sleeve 503 in turn compresses the outer ring of the tapered roller bearing, thereby eliminating the internal play of the bearing and establishing appropriate axial pre-tightening force between the bearing raceway and the rolling body. This pre-tightening force effectively suppresses the axial free play of the worm 3 in that direction. The adjustment needs to be extremely fine, usually turning the adjusting bolt 502 with a wrench for a small amount (such as 1 / 12 turn), while turning the worm 3 with your hand to feel the resistance change, until the worm 3 turns smoothly and there is no axial shaking feeling, and finally a locking nut (not shown in the figure, which can be set on the adjusting bolt) is used to lock it to prevent loosening. This adjustment process only affects the axial degree of freedom of the worm, and has no interference with the radial positioning of the worm and the position of the worm gear assembly 2, and is completely decoupled from the first adjusting mechanism 4 in function and operation.

[0029] To ensure long-term reliable operation and long service life of the reducer in harsh industrial environment, complete lubrication and sealing system is indispensable. In terms of lubrication, the lower half of the box 1 as the oil pool, filled with sufficient, viscosity grade suitable for worm gear transmission (such as ISO VG 460) of the extreme pressure industrial gear oil. Oil level should be at least submerged tooth root of worm 201, to ensure that the worm can bring oil in operation, splash lubrication of meshing tooth surface and the bearing below. For high speed or heavy load conditions, consider adding internal guide plate or external forced lubrication pump. In terms of sealing, the use of multi-seal combination: in all static combination surface, such as the first bearing seat 203, the second bearing seat 204, the installation surface between each end cover and the box 1, are installed in the rectangular or O type groove of oil resistant rubber O type sealing ring, realize static sealing. In all rotating shaft through, then use dynamic sealing: in the power output shaft hole 2031 of the first bearing seat 203, press a double lip or with dust lip rotating shaft lip seal (oil seal), its lip tightly adhere to the neck of the output shaft 202; in the first fixed end cover center hole of the worm 3 power input end and the center hole of the adjusting end cover 501, also install similar oil seal, to prevent lubricating oil along the shaft leakage and block external dust, moisture intrusion. In addition, in the box 1 top highest point or above the side, install a high efficiency air cap with metal filter screen and desiccant (not shown in the figure). Its role is crucial: it can balance the internal pressure generated by the working temperature rise of the reducer and the negative pressure generated by the cooling stop, prevent the positive pressure from causing leakage of the seal, or the negative pressure from sucking in the outside impurities; at the same time, its filtering function can ensure that the air entering the box is clean and dry.

[0030] The working principle and maintenance adjustment process of the present application can be briefly described as follows: power is transmitted from the power input end of the worm 3 to drive the worm 3 to rotate at high speed, and through the engagement of the helical teeth with the helical teeth of the worm wheel 201, a large speed ratio reduction is achieved and a large torque is output to the output shaft 202, and finally the external load is driven by the output shaft 202. After thousands of hours of operation, wear is inevitable. When the meshing side clearance of the worm wheel and worm increases to cause unstable transmission, without disassembling any internal parts, only the first adjusting mechanism 4 is operated, the radial overall fine adjustment of the entire worm wheel assembly 2 can be realized to accurately compensate. When the worm 3 appears axial movement, without disassembling its support structure, only the second adjusting mechanism 5 is operated, the independent and accurate readjustment of the axial bearing pre-tightening force can be realized by adjusting the bolt 502. Both adjustment operations are completed "online" in the state of complete assembly of the whole machine, the adjustment tool is simple (wrench, copper bar, dial gauge), the adjustment period is very short, and the traditional maintenance process of disassembling the box, taking out the shaft system, replacing the adjusting gasket, and re-aligning the alignment is completely abandoned. The backward process of high skill and easy to introduce secondary assembly error. This "integration, in-situ, independence" double gap compensation design, combined with the efficient lubrication and sealing system, together ensures that the transmission system can maintain in the best working clearance state for a long time, thereby greatly guarantees the stability and accuracy of the transmission, significantly reduces the running noise and vibration, greatly prolongs the service life and maintenance period of the speed reducer, and improves the reliability and economy of the entire transmission system.

[0031] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A worm gear reducer with adjustable clearance, characterized in that: include Box (1); The worm gear assembly (2) includes a worm gear (201), an output shaft (202) coaxially fixed with the worm gear (201), and a first bearing seat (203) and a second bearing seat (204) respectively disposed on both sides of the worm gear (201) and supporting the two ends of the output shaft (202). The worm gear assembly (2) is detachably mounted on the housing (1) via a first bearing seat (203) and a second bearing seat (204), and forms a whole after installation; The worm (3) is rotatably supported on the housing (1) by a bearing assembly (301) and meshes with the worm wheel (201); The first adjustment mechanism (4) is disposed between the first bearing seat (203) and the housing (1) and between the second bearing seat (204) and the housing (1), and is used to drive the worm gear assembly (2) to make a fine adjustment of its position relative to the housing (1) along the radial direction of the output shaft (202) to compensate for the meshing backlash between the worm gear (201) and the worm (3); The second adjustment mechanism (5) is set on the housing (1) and connected to one end of the worm (3), and is used to independently adjust the axial installation position of the worm (3) to compensate for the axial movement clearance of the worm (3).

2. The adjustable clearance worm gear reducer according to claim 1, characterized in that: The first bearing housing (203) is provided with a power output shaft hole (2031) through which the output shaft (202) passes; the second bearing housing (204) is provided with a bearing cavity (2041) on the side facing the worm gear (201) for accommodating the bearing to support the end of the output shaft (202); after installation, the first bearing housing (203) and the second bearing housing (204) respectively cover and close the opposite mounting openings (101) on the housing (1).

3. The adjustable clearance worm gear reducer according to claim 2, characterized in that: The first adjustment mechanism (4) includes an adjustment hole (401) opened on the first bearing seat (203) and / or the second bearing seat (204), and a fastener (402) passing through the adjustment hole (401) and locking the corresponding bearing seat to the housing (1); the extension direction of the adjustment hole (401) is parallel to the radial direction of the output shaft (202), and is used to adjustably mount the worm gear assembly (2) on the housing along the radial direction of the output shaft (202).

4. The adjustable clearance worm gear reducer according to claim 3, characterized in that: The adjustment hole (401) is an oblong hole and at least two are symmetrically arranged on a single bearing seat around the center of the output shaft (202). The width of the adjustment hole is adapted to the width of the mounting hole of the housing (1).

5. The adjustable clearance worm gear reducer according to claim 1, characterized in that: The second adjustment mechanism (5) is an axial adjustment assembly disposed at one end of the worm (3). The axial adjustment assembly includes an adjustment element that can move along the axial direction of the worm (3). The adjustment end of the adjustment element abuts against the bearing assembly (301) at one end of the worm (3) to adjust the installation position of the bearing assembly (301) at one end of the worm (3).

6. The adjustable clearance worm gear reducer according to claim 5, characterized in that: The axial adjustment assembly also includes an adjustment end cap (501) fixed to the housing (1), and the adjustment element is an adjustment bolt (502) threadedly connected to the adjustment end cap (501).

7. The adjustable clearance worm gear reducer according to claim 6, characterized in that: The axial adjustment assembly also includes a spacer (503) disposed between the adjusting bolt (502) and the bearing assembly (301) of the worm (3). The end of the adjusting bolt (502) abuts against the spacer (503), and the spacer (503) is driven to move axially by rotating the adjusting bolt (502).

8. The adjustable clearance worm gear reducer according to claim 7, characterized in that: The spacer (503) has a cylindrical structure. The bottom end of the spacer (503) abuts against the end of the adjusting bolt (502), and the top end of the spacer (503) abuts against the outer ring end face of the bearing assembly (301).

9. A worm gear reducer with adjustable clearance according to any one of claims 5-8, characterized in that: The bearing assembly (301) of the worm (3) is a pair of tapered roller bearings.

10. The adjustable clearance worm gear reducer according to claim 1, characterized in that: A sealing element is provided between the first bearing housing (203) and the housing (1), between the second bearing housing (204) and the housing (1), or at the support structure of the bearing assembly (301) of the worm gear (3).

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