Vibration and noise reduction worm supporting structure

Abstract

The invention discloses a vibration and noise reduction worm supporting structure, and belongs to the field of unmanned underwater vehicles, the vibration and noise reduction worm supporting structure comprises a shaft clamp, a right shell, a bearing pressing plate, an adjusting gasket, an angular contact bearing, a worm, a disc spring, a thrust ball bearing, a left shell, a deep groove ball bearing and a fixing screw, and the vibration and noise reduction worm supporting structure adopts the disc spring, the thrust ball bearing and the shell for bearing; and the angular contact bearing and the thrust ball bearing are radially positioned, so that flexible support is realized, the possibility that the rigidity of an oil film changes drastically and impact noise is generated in the process of switching a heavy load and a light load of a traditional worm rigid support structure is avoided, and low-vibration and low-noise work is realized.

Description

Technical Field

[0001] The invention belongs to the field of unmanned underwater vehicles, and in particular relates to a vibration-reducing and noise-reducing worm support structure. Background Art

[0002] In order to achieve self-locking, worm gear reducers are often used as actuators for underwater vehicles to control the rudder. The output shaft of the actuator is directly connected to the rudder, and the output angle is rotated by the output shaft to achieve the movement of the rudder. It is mainly composed of 1 control driver and 4 "servo motor + worm gear" servos.

[0003] In order to ensure that the servo makes less noise during operation, overall noise control index requirements are proposed to meet the needs of underwater silent navigation; due to the working properties of the rudder, the servo output shaft is under alternating load during operation; especially under heavy load, the deviation of the forward and reverse transmission stiffness will produce impact loads at the switching moment, thereby causing transmission noise.

[0004] At present, the support structure of the worm is mainly a rigid support structure, that is, two angular contact bearings are installed "back to back" and the bearing clearance is eliminated by the axial preload. Under the driving force of the motor, the worm overcomes the friction torque caused by the preload and rotates, thereby driving the worm wheel to rotate. In the process of overcoming the friction torque, it is inevitable that the shaft system will produce a transmission gap. Therefore, as the working time increases, the "rigid support structure" gradually changes to a "small gap support structure", and the "forward support stiffness" and "backward support stiffness" of the worm deviate, and the transmission noise will gradually increase. The oil film stiffness on one side of the transmission tooth between the worm wheel and the worm increases, while the oil film stiffness on the other side decreases, and there is a possibility of load impact during reversing.

[0005] Chinese patent CN217294647U discloses a worm support structure for an electric power-assist system, in which one end is connected to the housing through a four-point contact bearing, a riveted retaining ring is arranged inside the housing, and an O-type rubber ring is used for radial vibration reduction, and locking screws and riveted retaining rings are arranged at both ends of the housing for fixing the worm; one end of the worm is connected to the housing through a four-point contact bearing to provide stable support and reduce friction; an elastic rubber pad and an O-type rubber ring isolate the worm and the bearing, provide axial preload, and absorb impact loads at the same time ; A lubricating oil channel is set on the inside of the shell for bearing lubrication to reduce wear and friction; since the two ends of the shell are rigidly limited by locking screws and riveted retaining rings, the relative position of the worm cannot move under heavy load conditions; its load needs to be transferred to the shell through an elastic rubber pad, so the axial preload force is not a constant value, but changes with the change of load, and finally a transmission gap occurs; the oil film between the tooth gap of the worm wheel and the worm cannot be stable, and thus the lubrication of the tooth surface between the worm wheel and the worm cannot be guaranteed, especially at the switching moment, the load change is more obvious. Summary of the invention

[0006] The purpose of the present invention is to provide a vibration-damping and noise-reducing worm support structure, which adopts disc springs, thrust ball bearings and housings for bearing, and angular contact bearings and thrust ball bearings for radial positioning, to achieve flexible support, avoid the possibility of impact noise caused by drastic changes in oil film stiffness during the switching process between heavy load and light load of traditional worm rigid support structures, and achieve low vibration and low noise operation.

[0007] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0008] A vibration-damping and noise-reducing worm support structure comprises a shaft clamp, a right housing, a bearing pressure plate, an adjusting gasket, a first bearing, a worm, a disc spring, a second bearing, a left housing and a third bearing; one side of the worm contacts the first bearing and is positioned by the first bearing shoulder, and the other side contacts the disc spring; the other side of the disc spring contacts the second bearing, and the second bearing is limited by the left housing; an axial clearance exists between the third bearing and the left housing to radially position the worm, the shaft clamp limits the axial position of the third bearing, the right housing radially limits the first bearing, the bearing pressure plate is fixedly connected to the right housing, and the adjusting gasket is located between the bearing pressure plate and the first bearing.

[0009] It also includes fixing screws, through which the right housing and the bearing pressure plate are fastened and connected.

[0010] The bottom surface of the bearing pressure plate is square, and a convex stop is arranged in the center. The bearing pressure plate is connected to the right housing through the convex stop to ensure that the preload force of the worm coincides with the axis of the worm.

[0011] A circular boss is arranged on the upper surface of the convex stop, and the adjusting gasket is arranged around the circular boss and is limited by the circular boss.

[0012] The first bearing is an angular contact bearing, the second bearing is a thrust ball bearing, and the third bearing is a deep groove ball bearing.

[0013] The thickness of the adjustment gasket ranges from 0.5 to 1 mm.

[0014] Disc springs are combined in either laminated or composite forms.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] (1) The present invention adopts a flexible support structure of a disc spring and a thrust ball bearing, which has a significant suppressive effect on the load impact of the worm shaft system;

[0017] (2) The oil film stiffness of the present invention is stable, which reduces the possibility of dry friction on the tooth surface of the worm gear and achieves vibration reduction and noise reduction;

[0018] (3) The deep groove ball bearing of the present invention is only used for positioning and does not bear axial load, so a deep groove ball bearing with a smaller specification can be selected, thereby simplifying the structural layout;

[0019] (4) The present invention has a compact structure and its overall weight is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the vibration and noise reduction worm support structure of the present invention;

[0021] Figure 2 This is a cross-sectional view of the vibration and noise reduction worm support structure of the present invention;

[0022] Figure 3 This is a structural diagram of the bearing pressure plate of the vibration and noise reduction worm support structure of the present invention;

[0023] Figure 4 This is a comparison diagram of the flexible support and the rigid support of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 The figure shows a schematic diagram of the vibration-damping and noise-reducing worm support structure of the present invention, which includes a shaft clamp 1, a right housing 2, a bearing pressure plate 3, an adjustment gasket 4, an angular contact bearing 5, a worm 6, a disc spring 7, a thrust ball bearing 8, a left housing 9, a deep groove ball bearing 10, and a fixing screw 11.

[0026] like Figure 2 As shown, one end of the worm 6 contacts the angular contact bearing 5 and is positioned by a shaft shoulder; the other end of the worm 6 contacts the disc spring 7; the disc spring 7 contacts the thrust ball bearing 8, and the thrust ball bearing 8 is limited by the left housing 9, thereby limiting the maximum displacement of the worm 6 to the left; the initial position of the worm 6 can be achieved by adjusting the thickness of the adjusting gasket 4: when the number of disc springs 7 is constant, the stiffness of the disc spring 7 is constant, and increasing or decreasing the thickness of the adjusting gasket 4 means a change in the compression amount of the disc spring 7, thereby adjusting the preload force between the worm 6 and the angular contact bearing 5; the reaction force of the adjusting gasket 4 on the bearing pressure plate 3 is borne by the fixing screw 11, and the fixing screw 11 is rigidly connected to the right housing 2 through a thread; the deep groove ball bearing 10 only radially positions the worm 6, and there is an axial gap with the left housing 9, and the shaft clamp 1 limits the axial position of the deep groove ball bearing 10.

[0027] like Figure 3As shown, the bearing pressure plate 3 is designed with a convex stop 301, which cooperates with the right housing 2 to ensure that the preload force of the worm coincides with the axis of the worm; a circular boss 302 is provided on the upper surface of the convex stop 301, and the adjusting gasket 4 is arranged around the circular boss 302 and limited by the circular boss 302. The width of the contact surface between the adjusting gasket 4 and the bearing pressure plate 3 can be appropriately adjusted according to the actual load force requirements to reduce the contact stress of the adjusting gasket 4; the bearing pressure plate 3 is designed with multiple screw holes 303, which are symmetrically arranged. The size of the screw holes can be adjusted according to the size of the preload force to ensure the reliability of the connection between the right housing 2 and the bearing pressure plate 3.

[0028] In actual work, the oil film thickness is usually designed to be at the micron level. The initial design adjustment range of the disc spring 7 is 50 microns. The stiffness of the disc spring group can also be adjusted by increasing the number of combined springs according to the actual viscosity of the actual lubricating oil. The final result is that there is no impact noise in the reverse direction. The essence is flexible support, namely "elastic damping + viscous damping", which is compared with the rigid support method of the traditional worm gear. For example Figure 4 As shown:

[0029] The oil film is approximated as a viscous damper, and its stiffness is related to the speed change between the turbine and worm. When the traditional turbine and worm are rigidly supported, a transmission gap gradually appears between the turbine and the worm to ensure flexible transmission, thereby reducing the transmission stiffness. At the same time, since the preload is usually applied on one side of the angular contact bearing, the stiffness of the oil film transmitted between the turbine and worm is inconsistent. When the turbine and worm move relative to each other, the impact load cannot be borne by the deformation of the shell, and the related load is borne by the oil film. With the flexible support method of the present invention, the impact load can be smoothly absorbed by the disc spring, ensuring that the oil film stiffness remains basically consistent during the reversing process of the turbine and worm.

[0030] The stiffness of disc spring 7 can be calculated by the following formula:

[0031]

[0032] Where K is the stiffness of the disc spring; E is the elastic modulus; t is the thickness of the disc spring; K1 is the calculation coefficient; U is the Poisson's ratio; and D is the outer diameter of the disc spring. The calculation coefficient K1 is:

[0033]

[0034] Where C is the ratio of the outer diameter to the inner diameter, that is, d is the inner diameter of the disc spring.

[0035] Disc springs are relatively commonly used standard parts, which are combined in overlapping or compound ways to adjust the spring stiffness. According to actual needs, D=50mm, d=25.4mm, t=3mm are selected, and the combined preload force reaches 25000N, which can meet the actual load force requirements.

[0036] The thrust ball bearing (8) is 51305, with an inner diameter of 25 mm, an outer diameter of 52 mm, a thickness of 18 mm, and a basic rated dynamic load of 35.7 kN, matching the disc spring 7;

[0037] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0038] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A vibration-damping and noise-reducing worm support structure, comprising a shaft clamp (1), a right housing (2), a bearing pressure plate (3), an adjusting gasket (4), a first bearing (5), a worm (6), a disc spring (7), a second bearing (8), a left housing (9) and a third bearing (10); one side of the worm (6) contacts with the first bearing (5) and is positioned by the shaft shoulder of the first bearing (5), and the other side contacts with the disc spring (7); the other side of the disc spring (7) contacts with the second bearing (8), and the second bearing (8) is limited by the left housing (9); an axial clearance exists between the third bearing (10) and the left housing (9), and the worm (6) is radially positioned; the shaft clamp (1) limits the axial position of the third bearing (10), the right housing (2) radially limits the first bearing (5), the bearing pressure plate (3) is fixedly connected to the right housing (2), and the adjusting gasket (4) is located between the bearing pressure plate (3) and the first bearing (5).

2. A vibration and noise reduction worm support structure according to claim 1, characterized in that: It also includes a fixing screw (11), and the right housing (2) and the bearing pressure plate (3) are fastened and connected by the fixing screw (11).

3. The vibration and noise reduction worm support structure according to claim 1, characterized in that: The bottom surface of the bearing pressure plate (3) is square, and a convex stop (301) is arranged at the center. The bearing pressure plate (3) is connected to the right housing (2) via the convex stop (301), ensuring that the preload force of the worm coincides with the axis of the worm.

4. The vibration and noise reduction worm support structure according to claim 3, characterized in that: A circular boss (302) is arranged on the upper surface of the convex stop (301), and the adjusting gasket (4) is arranged around the circular boss (302) and is limited by the circular boss (302).

5. The vibration and noise reduction worm support structure according to claim 1, characterized in that: The first bearing (5) is an angular contact bearing, the second bearing (8) is a thrust ball bearing, and the third bearing (10) is a deep groove ball bearing.

6. The vibration and noise reduction worm support structure according to claim 1, characterized in that: The thickness of the adjusting gasket (4) is in the range of 0.5-1 mm.

7. The vibration and noise reduction worm support structure according to claim 1, characterized in that: The disc spring (7) is combined in a stacked or compound manner.

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