Torque limiter and method for setting its limit range

Abstract

This invention relates to the field of aerospace transmission technology, and provides a torque limiter and its limiting range setting method. The torque limiter includes: a front ball-and-socket shaft, several balls, a starting friction ring, a rear ball-and-socket shaft, a limiting friction disc, a clamping spring, a clamping nut, and an output shaft. The front ball-and-socket shaft transmits the input torque to the rear ball-and-socket shaft through the balls. When the input torque is lower than the starting torque, the rear ball-and-socket shaft remains in contact with the starting friction ring under the action of the clamping spring, and the output shaft does not rotate. When the input torque is greater than the maximum limiting torque, the balls press the rear ball-and-socket shaft against the limiting friction disc, thereby limiting the output torque of the output shaft. When the input torque is greater than the starting torque but less than the maximum limiting torque, the rear ball-and-socket shaft only contacts the balls, and the torque is transmitted from the front ball-and-socket shaft to the balls, and then from the rear ball-and-socket shaft to the output shaft. The provided torque limiter has a simple structure, no slippage after over-torque, controllable rotation angle, and no need for reset.

Description

Technical Field

[0001] This invention belongs to the field of aerospace transmission technology, and particularly relates to a torque limiter and a method for setting its limiting range. Background Technology

[0002] The torque limiter is mainly used to transmit torque between the drive shaft and the driven shaft. When the input of the drive shaft fails and there is a small torque error, the torque limiter will not work, thus playing a role in start-up identification. When the load of the driven shaft fails and the torque exceeds the set maximum torque, the torque limiter limits the torque in the transmission system by friction, thus playing a role in overload protection.

[0003] Existing torque limiters mostly limit the maximum torque by causing steel balls to slip and swerve, resulting in uncontrolled input and output angles. Aerospace torque limiters must ensure accurate correspondence between input and output angles. Many existing torque limiters lack minimum torque limits, leading to erroneous outputs due to incorrect inputs. Aerospace torque limiters must be able to identify the input torque and filter low torque to ensure reliable output. Furthermore, due to the precious nature of launch payloads, aerospace torque limiters must have a torque limit range setting function to adapt to various application scenarios, thereby maximizing reusability. Summary of the Invention

[0004] To address the aforementioned problems, the inventors have conducted intensive research and developed a torque limiter and its limiting range setting method. This method enables the setting of starting torque and limiting torque, and ensures the synchronization between the input and output rotation angles, thus meeting the application requirements of torque limiters for aerospace applications.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A torque limiter, the torque limiter comprising: a torque transmission device, a torque limiting device, and a housing device;

[0007] The torque transmission device includes a front ball bearing, a sliding bearing, a ball bearing, a rear ball bearing, a compression spring, a compression nut, and an output shaft. One side of the front ball bearing is connected to the input end of the torque, and the compression spring is wrapped around the outside of the other side of the shaft and passes through the cavity of the rear ball bearing. The front ball bearing and the rear ball bearing each have several ball sockets on their shaft surfaces, and a ball bearing is installed between every two corresponding ball sockets.

[0008] The torque limiting device includes a starting friction ring and a limiting friction disc, which are fixed to the housing device and contact and act on the rear ball joint shaft;

[0009] The housing device includes a front cover, a rear cover, and a limiting sleeve. The front cover and the rear cover are connected by a plurality of long screws. The limiting sleeve is wrapped around the long screws and is used to determine the lateral position of the starting friction ring.

[0010] Furthermore, torque is input from the front disc shaft, transmitted through the ball sockets on the front disc shaft, the balls, and the ball sockets on the rear disc shaft, and finally output by the output shaft.

[0011] Furthermore, the clamping nut is threaded to the end of the front ball joint shaft, and its position on the front ball joint shaft can be adjusted by rotating it, thereby changing the compression of the clamping spring and adjusting the starting torque of the torque limiter.

[0012] Furthermore, the tapered surface of the rear ball joint shaft presses against the starting friction ring under the action of the compression spring, so that the input torque must reach the designed minimum force value to drive the rear ball joint shaft.

[0013] Furthermore, the geometry of the spherical socket is formed by sweeping a sphere across a three-dimensional spatial curve projected onto a cylindrical surface by an arc.

[0014] Furthermore, the ball is not in a fixed position when transmitting torque, but moves up and down in the ball socket according to the magnitude of the transmitted torque. When the torque is greater, its position is closer to the shallow part of the ball socket.

[0015] Furthermore, the rear ball joint shaft will undergo axial displacement during torque transmission. When the torque reaches the designed maximum force value, the back side of the rear ball joint shaft will contact the limiting friction disc, thereby canceling out the torque and limiting the magnitude of the transmitted torque.

[0016] Furthermore, the output shaft is connected to the rear ball joint shaft via four convex keys, allowing the rear ball joint shaft to transmit torque to the output shaft without restricting its own axial displacement.

[0017] Furthermore, the thickness of the limiting friction disc can be changed by adding or removing shims, thereby changing the maximum axial displacement space on the back side of the rear ball joint shaft, and thus adjusting the maximum limiting torque of the torque limiter.

[0018] Furthermore, a method for setting the limiting range using the torque limiter described above includes the following steps:

[0019] S1: Unscrew the four long screws connecting the front end cover and the rear end cover, and remove the rear end cover;

[0020] S2: Calculate the tightening amount of the clamping nut using the formula:

[0021]

[0022] Wherein the starting torque is the minimum working torque value of the torque limiter to be set, the starting friction radius is the average radius value of the friction surface on the starting friction ring from the axis, the friction coefficient is the friction coefficient value between the starting friction ring and the rear ball bearing shaft, and the spring stiffness is the stiffness K value of the compression spring;

[0023] S3: Tighten the clamping nut to the initial position to reset it, and then tighten it to the left by the specified amount;

[0024] S4: Calculate the thickness of the limiting friction disc using the formula:

[0025]

[0026] Wherein, the structural clearance is the maximum distance between the rear ball socket shaft and the rear end cover without input torque, the arc diameter of the ball socket is the initial arc diameter of the ball socket on the rear ball socket shaft, the limiting torque is the maximum working torque of the torque limiter to be set, the spring clamping force is the clamping force of the clamping spring, and the diameter of the ball socket cylindrical surface is the diameter of the projected cylindrical surface of the ball socket on the rear ball socket shaft;

[0027] S5: Adjust the mounting shims of the friction disc;

[0028] S6: Reinstall the rear end cover and tighten the mounting screws.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The starting friction ring is used to identify the torque limiter, so that the torque limiter only starts to work when the torque reaches a certain value, thus ensuring the safety and reliability of the output.

[0031] (2) The limiting friction disc is used to limit the movement so that the input and output shafts of the torque limiter do not slip, thus ensuring that the rotation angles between the input and output are corresponding.

[0032] (3) The transmission structure design of the front and rear ball bearings and bearings makes the torque-to-mass ratio of the entire limiter large and does not require reset after input overload.

[0033] (4) The structure design of the ball socket is effective and reliable, and the clear formulas for starting torque and limiting torque make the parameter setting of the designed torque limiter simple and accurate.

[0034] The following will further explain the concept, specific structure and effects of the present invention with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. Attached Figure Description

[0035] Figure 1 A schematic cross-sectional view of the designed torque limiter;

[0036] Figure 2 A schematic cross-sectional view of an overloaded torque limiter according to the invention.

[0037] Figure 3 A schematic diagram of the front and rear ball joints of a torque limiter.

[0038] Figure 4 A schematic diagram of the ball-and-socket transmission mechanism for a designed torque limiter;

[0039] Figure 5 This is a flowchart illustrating the setup process of a torque limiter invented.

[0040] Figure Labels

[0041] 1: Front ball joint shaft; 2: Front end cover; 3: Sliding bearing; 4: Ball bearing; 5: Limiting sleeve; 6: Starting friction ring; 7: Rear ball joint shaft; 8: Limiting friction disc; 9: Compression spring; 10: Compression nut; 11: Output shaft; 12: Rear end cover;

[0042] 21: Ball hole. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0045] Existing torque limiters mostly limit the maximum torque by causing steel balls to slip and swerve, resulting in uncontrolled input and output angles. Aerospace torque limiters must ensure accurate correspondence between input and output angles. Many existing torque limiters lack minimum torque limits, leading to erroneous outputs due to incorrect inputs. Aerospace torque limiters must be able to identify the input torque and filter low torque to ensure reliable output. Furthermore, due to the precious nature of launch payloads, aerospace torque limiters must have a torque limit range setting function to adapt to various application scenarios, thereby maximizing reusability.

[0046] This invention provides a torque limiter and a method for setting its limit range. By activating the friction ring 6, the minimum value of the transmitted torque is limited so that the device only starts working under a certain amount of torque. By limiting the friction disc 8, the maximum value of the transmitted torque is limited, and the portion exceeding the maximum limit torque is dissipated by friction, ensuring reliable installation of the output.

[0047] First Embodiment

[0048] like Figure 1 The diagram shown is a structural schematic of a torque limiter provided in this embodiment, specifically including the following structures:

[0049] The torque transmission device includes a front ball joint shaft 1, balls 4, a rear ball joint shaft 7, a clamping spring 9, a clamping nut 10, and an output shaft 11. One side of the front ball joint shaft 1 is connected to the torque input end, and the other side of the shaft is fitted with a clamping spring 9, both passing through the cavity of the rear ball joint shaft 7. (The last sentence appears to be incomplete and possibly refers to a different device.) Figure 3 As shown, the front ball bearing shaft 1 and the rear ball bearing shaft 7 each have three ball sockets 21 on their axial surfaces, and a ball bearing 4 is installed between every two corresponding ball sockets 21; the torque limiting device includes a starting friction ring 6 and a limiting friction disc 8, which are fixed to the front end cover 1 and the rear end cover 12, and contact and act on the rear ball bearing shaft 7; the outer casing includes the aforementioned front end cover 1, rear end cover 12 and limiting sleeve 5, which are connected to the front end cover 1 and the rear end cover 12 by four long screws, and the limiting sleeve 5 is wrapped around the long screws to determine the lateral position of the starting friction ring 6.

[0050] Furthermore, the left side shaft of the front ball bearing shaft 1 of the present invention is connected to the torque input end, and the torque is transmitted through the ball bearing 21, the ball bearing 4 and the ball bearing on the rear ball bearing shaft 7, and finally output by the output shaft 11.

[0051] Furthermore, such as Figure 1As shown, the conical surface of the rear ball joint shaft 7 presses against the starting friction ring 6 under the action of the compression spring 9, so that the input torque must reach the designed minimum force value to drive the rear ball joint shaft 7. Specifically, in this embodiment, the front ball joint shaft 1 transmits the input torque to the rear ball joint shaft 7 through the ball bearings 4. When the input torque is lower than the starting torque, the conical surface of the rear ball joint shaft 7 remains in contact with the starting friction ring 6 under the action of the compression spring 9, and the output shaft 11 does not rotate; when the input torque is greater than the maximum limiting torque, such as Figure 2 As shown, this is an overload state of a torque limiter in this embodiment. During the transmission of torque, the rear ball bearing shaft 7 will undergo axial displacement. The balls 4 press the back of the rear ball bearing shaft 7 against the limiting friction disc 8, thereby canceling out the torque and limiting the magnitude of the transmitted torque. When the input torque is greater than the starting torque and less than the maximum limiting torque, the rear ball bearing shaft 7 only contacts the balls 4. The torque is transmitted from the front ball bearing shaft 1 to the balls 4, and then from the rear ball bearing shaft 7 to the output shaft 11.

[0052] Specifically, in this embodiment, the adjusting nut 10 is threadedly connected to the front ball bearing shaft 1. Rotating it can adjust its position on the front ball bearing shaft 1, thereby changing the compression of the compression spring 9, and thus adjusting the starting torque of the torque limiter.

[0053] Preferably, the output shaft 11 is connected to the rear ball joint shaft 7 via four convex keys, which allows the rear ball joint shaft 7 to transmit torque to the output shaft 11 without restricting its own axial displacement.

[0054] More preferably, the limiting friction disc 8 of the present invention can change its thickness by adding or removing shims, thereby changing the maximum axial displacement space on the back side of the rear ball bearing shaft 7, thereby realizing the adjustment of the limiting torque of the torque limiter.

[0055] Furthermore, such as Figure 3 The diagram shows a ball-and-socket transmission schematic of a torque limiter according to this embodiment. Both the front ball-and-socket disc shaft 1 and the rear ball-and-socket disc shaft 7 have three ball sockets 21, with a ball 4 installed between every two corresponding ball sockets 21. When transmitting torque, the ball 4 is not in a fixed position, but moves up and down within the ball socket 21 depending on the magnitude of the transmitted torque. When the torque is greater, its position is closer to the shallower part of the ball socket 21; when the torque is smaller, its position is closer to the deeper part of the ball socket 21, thus establishing a mapping relationship between the transmitted torque and the axial displacement of the rear ball-and-socket disc.

[0056] Specifically, in this embodiment, such as Figure 4As shown, the design process of the ball socket is as follows: An initial arc is designed on a plane perpendicular to the end face of the ball socket disk, ensuring that its center passes through the projection of the ball socket disk's axis onto this plane, and that the lowest point of the arc is 2 / 5 the diameter of the ball 4 below the end face of the ball socket disk; then, a cylindrical surface coaxial with the ball socket disk is designed, with a diameter generally half the diameter of the ball socket disk; the initial arc is projected onto the cylindrical surface to obtain a spatial arc curve; the ball socket disk is then scanned and cut along this spatial arc curve using a circular cross-section with the same diameter as the ball 4, thus obtaining a simple, reliable, and easy-to-manufacture ball socket type.

[0057] Second Embodiment

[0058] like Figure 5 The diagram shows a flowchart for setting the limiting range of a torque limiter according to the present invention. Specifically, when it is necessary to reset the limiting range of the torque limiter, the operator can first unscrew the four long screws connecting the front end cover 2 and the rear end cover 12, remove the rear end cover 12, and then calculate the tightening amount of the clamping nut 10 using the following formula:

[0059]

[0060] Then tighten the clamping nut 10 back to its initial position to reset it, and then tighten it to the left by the specified amount. Finally, calculate the thickness of the limiting friction disc 8 using the following formula:

[0061]

[0062] Then adjust the mounting shims of the limiting friction disc 8, and finally reinstall the rear end cover 12 and tighten the mounting screws. The parameters in the formula are as follows: starting torque is the minimum working torque value of the limiter to be set; starting friction radius is the average radius of the friction surface on the starting friction ring 6 from the axis; friction coefficient is the friction coefficient between the starting friction ring 6 and the rear ball-and-socket disc shaft 7; spring stiffness is the stiffness K value of the compression spring 9; structural clearance is the maximum distance between the rear ball-and-socket disc shaft 7 and the rear end cover 12 without input torque; ball-and-socket arc diameter is the initial arc diameter value of the ball-and-socket on the rear ball-and-socket disc shaft 7; limiting torque is the maximum working torque value of the limiter to be set; spring clamping force is the clamping force value of the compression spring 9; and ball-and-socket cylindrical surface diameter is the diameter value of the projected cylindrical surface of the ball-and-socket on the rear ball-and-socket disc shaft 7.

[0063] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A torque limiter, characterized in that, include: Torque transmission device, torque limiting device, and housing device; The torque transmission device includes a front ball bearing shaft, a ball bearing, a rear ball bearing shaft, a compression spring, a compression nut, and an output shaft. One side of the front ball bearing shaft is connected to the torque input end, and the compression spring is wrapped around the other side of the shaft and passes through the cavity of the rear ball bearing shaft. The shaft surfaces of the front ball bearing shaft and the rear ball bearing shaft each have several ball sockets, and a ball bearing is installed between every two corresponding ball sockets. The torque limiting device includes a starting friction ring and a limiting friction disc, which are fixed to the housing device and contact and act on the rear ball joint shaft; The outer casing includes a front cover, a rear cover, and a limiting sleeve. The front cover and the rear cover are connected by a plurality of long screws. The limiting sleeve is wrapped around the long screws and is used to determine the lateral position of the starting friction ring.

2. The torque limiter according to claim 1, characterized in that, Torque is input from the front ball bearing shaft, transmitted through the balls on the front ball bearing shaft, the balls, and the balls on the rear ball bearing shaft, and finally output by the output shaft.

3. The torque limiter according to claim 1, characterized in that, The clamping nut is threaded to the end of the front ball joint shaft. Rotating it can adjust its position on the front ball joint shaft, thereby changing the compression of the clamping spring and adjusting the starting torque of the torque limiter.

4. The torque limiter according to claim 1, characterized in that, The tapered surface of the rear ball joint shaft presses against the starting friction ring under the action of the compression spring, so that the input torque must reach the designed minimum force value to drive the rear ball joint shaft.

5. The torque limiter according to claim 1, characterized in that, The geometry of the sphere is formed by sweeping a sphere across a three-dimensional spatial curve projected onto a cylindrical surface by an arc.

6. The torque limiter according to claim 1, characterized in that, The ball is not in a fixed position when transmitting torque, but moves up and down in the ball socket according to the magnitude of the transmitted torque. When the torque is greater, its position is closer to the shallow part of the ball socket.

7. The torque limiter according to claim 1 or 2, characterized in that, During the torque transmission process, the rear ball joint shaft will undergo axial displacement. When the torque reaches the designed maximum force value, the back of the rear ball joint shaft will contact the limiting friction disc, thereby canceling out the torque and limiting the magnitude of the transmitted torque.

8. The torque limiter according to claim 1 or 2, characterized in that, The output shaft is connected to the rear ball joint shaft via four protruding keys, allowing the rear ball joint shaft to transmit torque to the output shaft without restricting its own axial displacement.

9. The torque limiter according to claim 1, characterized in that, The thickness of the limiting friction disc can be changed by adding or removing shims, thereby changing the maximum axial displacement space on the back of the rear ball joint shaft, and thus adjusting the maximum limiting torque of the torque limiter.

10. A method for setting the limiting range of a torque limiter as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Unscrew the four long screws connecting the front end cover and the rear end cover, and remove the rear end cover; S2: Calculate the tightening amount of the clamping nut using the formula: Wherein the starting torque is the minimum working torque value of the torque limiter to be set, the starting friction radius is the average radius value of the friction surface on the starting friction ring from the axis, the friction coefficient is the friction coefficient value between the starting friction ring and the rear ball bearing shaft, and the spring stiffness is the stiffness K value of the compression spring; S3: Tighten the clamping nut to the initial position to reset it, and then tighten it to the left by the specified amount; S4: Calculate the thickness of the limiting friction disc using the formula: Wherein, the structural clearance is the maximum distance between the rear ball socket shaft and the rear end cover without input torque, the arc diameter of the ball socket is the initial arc diameter of the ball socket on the rear ball socket shaft, the limiting torque is the maximum working torque of the torque limiter to be set, the spring clamping force is the clamping force of the clamping spring, and the diameter of the ball socket cylindrical surface is the diameter of the projected cylindrical surface of the ball socket on the rear ball socket shaft; S5: Adjust the mounting shims of the friction disc; S6: Reinstall the rear end cover and tighten the mounting screws.

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