Clutch gear based on rolling body locking and electromagnetic control

Abstract

The application provides a kind of clutch gear based on rolling body locking and electromagnetic control, belongs to mechanical transmission technical field.The clutch gear includes: clutch shaft, input gear coaxially installed on clutch shaft, output gear that is axially sleeved on the both ends of input gear on clutch shaft and control ring;Transmission ball is movably received in the axial guide hole of input gear, can produce axial displacement under the action of control ring, to realize the power connection or separation between input gear and output gear;Control ring has shear boss inserted into magnetorheological fluid, can rotate relative to input gear by a set angle under the action of shear viscous resistance generated by magnetorheological fluid or the action of tangential spring restoring force between control ring and output gear, to push transmission ball to produce axial displacement.

Description

Technical Field

[0001] This invention relates to a clutch gear, specifically a clutch gear based on rolling element locking and electromagnetic control, belonging to the technical field of mechanical transmission devices. Background Technology

[0002] A clutch gear is a mechanical device that transmits power through forward and reverse rotation. Based on the principle of gear teeth engaging and disengaging, clutch gears are often used as a protective mechanism in transmission systems. They limit the maximum load on the gears, thus protecting the drive system. Clutch gears have the advantages of fewer parts, compact structure, fast response, and convenient control, and are widely used in micro servo systems, industrial equipment, and other applications.

[0003] Traditional toothed spring clutch gears use serrated teeth between the driving and driven gears to convert torque into axial displacement through the helical angle of the tooth surface to achieve overload protection. Springs are usually required to provide clamping force, and the clutch spring is the most critical component in designing the protection threshold.

[0004] Although the above-mentioned spring-type clutch structure is simple in structure, it has the following significant drawbacks in practical applications, especially in scenarios requiring high performance and high reliability: (1) The clutch torque of the spring clutch structure depends entirely on the stiffness coefficient and pre-compression of the spring. Once the product is assembled, its overload protection threshold is physically fixed, resulting in poor versatility.

[0005] (2) As the core force-applying element, the spring will undergo fatigue creep during long-term stress and repeated compression, resulting in a gradual decrease in preload. This causes the clutch slippage threshold to decrease over time, leading to false slippage of the servo motor even under normal working load, affecting transmission accuracy and lifespan.

[0006] (3) Active disengagement is not possible; the spring-type structure is always in a normally closed state and only passively disengages under overload. In certain scenarios where the output shaft needs to rotate freely or where power needs to be quickly cut off to prevent injury, existing technology cannot actively disengage the clutch via control signals. Summary of the Invention

[0007] In view of this, the present invention provides a clutch gear based on rolling element locking and electromagnetic control, which has advantages such as fast response speed, high control accuracy and long service life compared with the spring solution that relies on mechanical preload.

[0008] The technical solution of the present invention is: a clutch gear structure based on rolling element locking and electromagnetic control, comprising: a clutch shaft, an input gear coaxially mounted on the clutch shaft, an output gear loosely fitted on both axial ends of the input gear on the clutch shaft, and a control ring; The transmission balls are movably housed in the axial guide hole of the input gear and can generate axial displacement under the action of the control ring to realize the power engagement or disengagement between the input gear and the output gear; The control ring has a shear boss that is inserted into the magnetorheological fluid. Under the action of the shear viscous resistance generated by the magnetorheological fluid or the action of the restoring force of the tangential spring between the control ring and the output gear, it can rotate relative to the input gear at a set angle to drive the transmission ball to produce axial displacement.

[0009] As a preferred embodiment of the present invention: a groove is provided on the end face of the input gear facing the control ring, which allows the control ring to be embedded, and a plurality of spring receiving grooves A and a plurality of axial guide holes are distributed alternately along the circumference in the groove; The axial guide hole is a through hole, and its effective axial length is less than the diameter of the transmission ball. On the end face of the control ring facing the input gear, there are spring receiving grooves B distributed circumferentially, each corresponding to a spring receiving groove A. When the input gear is fitted and assembled with the control ring, the spring receiving groove A and the spring receiving groove B, which are arranged opposite to each other, interlock to form a closed spring receiving cavity; a tangential spring is provided in each spring receiving cavity; one axial end of the tangential spring abuts against the end wall of the spring receiving groove A, and the other axial end abuts against the end wall of the opposite end of the spring receiving groove B.

[0010] As a preferred embodiment of the present invention: the control ring has drive grooves and spring receiving grooves B that are staggered along the circumference on the end face of the input gear; The drive groove has a wedge-shaped drive ramp; the wedge-shaped drive ramp is formed by connecting a low-position reset surface, a linear transition slope and a high-position locking surface in sequence; the end of the drive groove with a smaller groove depth is provided with an arc surface as the high-position locking surface of the transmission ball; the end with a larger groove depth is the low-position reset surface, which transitions with the linear transition slope with an arc.

[0011] As a preferred embodiment of the present invention: a cylindrical protrusion is provided on the end face of the output gear facing the input gear, and a plurality of radial locking V-grooves are evenly distributed along the circumferential direction on the end face of the cylindrical protrusion; When the transmission ball is located at the position of the low-position reset surface on the control ring, the transmission ball is located in the axial guide hole between the low-position reset surface and the input gear, and the clutch gear is in a disengaged state at this time. When the transmission ball is located at the high locking surface on the control ring, the transmission ball is located in the high locking surface, the axial guide hole of the input gear, and the radial locking V groove. The transmission ball causes the control ring, the input gear, and the output gear to form a locking relationship, and the clutch gear is in the engaged state at this time.

[0012] As a preferred embodiment of the present invention: a circumferential buffer track is provided on the end face of the cylindrical protrusion of the output gear, and the circumferential buffer track is connected to the radial locking V groove.

[0013] As a preferred embodiment of the present invention: the back of the control ring is provided with an annular protrusion as a shearing boss, the shearing boss is inserted into the annular liquid storage cavity of the electromagnetic stator assembly, and a uniform micro-shearing gap is formed between the annular liquid storage cavity and the inner and outer walls of the annular liquid storage cavity; the annular liquid storage cavity is filled with magnetorheological fluid.

[0014] As a preferred embodiment of the present invention: a sealing element is provided at the opening of the annular liquid storage cavity, and the sealing element abuts against the root circumferential surface of the control ring shear boss in a dynamic sealing manner.

[0015] Beneficial effects: (1) This invention uses the viscous resistance generated by magnetorheological fluid to replace the mechanical elastic force in the traditional scheme. The viscosity of the magnetorheological fluid can be precisely controlled by the current (the viscosity of the magnetorheological fluid is related to the magnetic flux, that is, the damping force generated is a function of the magnetic field strength, and the magnetic field strength can be changed by controlling the current). It has a fast response speed and high control accuracy, and can more effectively control the magnitude of the overload protection force.

[0016] (2) In this invention, a composite guiding mechanism of "ball rolling + buffer track" is adopted: when an overload occurs, the transmission ball jumps out of the radial locking V groove and falls into the circumferential buffer track for pressureless sliding, rather than impact. The original destructive mechanical impact is transformed into smooth motion sliding, which extends the life of the clutch and significantly reduces the maintenance cost of the system.

[0017] (3) This invention can directly achieve instantaneous separation of input and output by switching the electromagnetic stator assembly on and off, allowing the motor to continue running without stopping. This feature completely eliminates the motor starting shock caused by frequent start-stop, thereby effectively protecting the drive circuit and mechanical components and extending the service life of the entire power system. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the electromagnetic clutch gear of the present invention; Figure 2 This is an axial cross-sectional view of the electromagnetic clutch gear of the present invention. Figure 3 A three-dimensional structural diagram of the input gear; Figure 4 Input the front view of the gear; Figure 5 This is a schematic diagram of the output gear. Figure 6 This is a schematic diagram of the control loop structure; Figure 7 A partial cross-sectional view of the drive groove on the control ring; Figure 8 This is a schematic diagram of the mechanical analysis of the torque formula.

[0019] Wherein: 1-Input gear, 101-Groove, 102-Spring receiving groove A, 103-Axial guide hole, 2-Output gear, 201-Circumferential buffer track, 202-Radial locking V groove, 203-Cylindrical protrusion, 3-Electromagnetic stator assembly, 4-Transmission ball, 5-Tangential spring, 6-Control ring, 601-Drive groove, 6011-Low position reset surface, 6012-Linear transition slope, 6013-High position locking surface, 602-Spring receiving groove B, 603-Shear boss, 7-Clutch shaft, 8-Magnetorheological fluid, 9-Seal. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] This embodiment provides a clutch gear structure based on rolling element locking and electromagnetic control, which completely replaces the original passive spring force drive system with an active electromagnetic drive system, significantly improving the overall performance and intelligence level of the transmission system.

[0022] like Figure 1 and Figure 2 As shown, the clutch gear structure adopts a unique coaxial nested structure, with the following components arranged coaxially along the power transmission direction: control ring 6, input gear 1, and output gear 2. In addition, it also has an electromagnetic stator assembly 3 as a control component and transmission balls 4 (i.e., rolling elements).

[0023] The input gear 1 is coaxially mounted on the clutch shaft 7 (such as a motor shaft) and can rotate under the drive of the motor. The output gear 2 and the control ring 6 are respectively loosely fitted on the clutch shaft 7 at both axial ends of the input gear 1. The output gear 2 is connected to the load. The transmission balls 4 are movably housed in the axial guide hole of the input gear 1 and can generate axial displacement under the drive of the control ring 6 to realize the power engagement or disengagement between the input gear 1 and the output gear 2.

[0024] like Figure 3 and Figure 4As shown, the input gear 1 is a cylindrical gear structure. On the end face of the input gear 1 facing the control ring 6, there is a groove 101 that allows the control ring 6 to be partially embedded. Several spring receiving grooves A102 and several axial guide holes 103 are distributed circumferentially within the groove 101 (in this example, there are three spring receiving grooves A102 and three axial guide holes 103). The spring receiving grooves A102 and the axial guide holes 103 are evenly spaced circumferentially. The axial guide holes 103 are through holes, and their effective axial length is less than the diameter of the transmission ball 4, so that the transmission ball 4 can protrude backward in the retracted state and protrude forward in the ejected state (here, the output gear 2 is in the "front" and the input gear 1 is in the "rear").

[0025] The control ring 6 is made of magnetic material, coaxially positioned behind the input gear 1, and can rotate within a limited angle (i.e., a set angle) relative to the input gear 1. Figure 6 As shown, on the end face of the control ring 6 facing the input gear 1, drive grooves 601 with wedge-shaped drive surfaces and spring receiving grooves B602 are distributed circumferentially in an alternating pattern. (In this example, three drive grooves 601 and three spring receiving grooves B602 are provided.) The spring receiving grooves B602 correspond one-to-one with the spring receiving grooves A102.

[0026] In this clutch gear, several pairs of arc-shaped grooves (spring receiving grooves B602 and A102, respectively) are correspondingly formed on the end face of the input gear 1 facing the control ring 6 and the end face of the control ring 6 facing the input gear 1. When the input gear 1 and the control ring 6 are fitted together, the pairs of arc-shaped grooves interlock to form a closed spring receiving cavity. Each spring receiving cavity contains a tangential spring 5 (the axial direction of the tangential spring 5 is along the circumference of the input gear 1 and the control ring 6); one axial end of the tangential spring 5 abuts against the end wall of the spring receiving groove A102 on the input gear 1, and the other axial end abuts against the end wall of the opposite end of the spring receiving groove B602 on the control ring 6. This structure uses the end wall of the arc-shaped groove on the input gear 1 facing the control ring 6 as the force application point to achieve the elastic reset of the tangential spring 5, thereby driving the control ring 6 to reset.

[0027] The back of the control ring 6 is provided with an annular protrusion as a shearing boss 603. The shearing boss 603 can be inserted into the annular liquid storage cavity of the electromagnetic stator assembly 3, forming a uniform micro shearing gap between the inner and outer walls of the annular liquid storage cavity of the electromagnetic stator assembly 3.

[0028] The drive groove 601 on the end face of the control ring 6 has a wedge-shaped drive ramp. For example... Figure 6As shown, the wedge-shaped drive ramp is formed by sequentially connecting a low-position reset surface 6011, a linear transition slope 6012, and a high-position locking surface 6013. Specifically, the bottom surface of the drive groove 601 is an inclined surface set along the length of the groove; this inclined surface is the linear transition slope 6012. The end with the smaller groove depth has an arc-shaped surface (slightly concave) as a limiting structure for the transmission ball 4, which is the high-position locking surface 6013. The end with the larger groove depth transitions to the linear transition slope 6012 with an arc; this part is the low-position reset surface 6011.

[0029] The electromagnetic stator assembly 3 is fixed to the housing. An annular liquid reservoir 8 is located inside the electromagnetic stator assembly 3. A shearing boss 603 on the back of the control ring 6 extends into this reservoir. When the electromagnetic stator assembly 3 is energized, the magnetorheological fluid 8 undergoes a rheological effect (changing from liquid to semi-solid), generating significant shear viscous resistance on the shearing boss 603. This generates a braking torque to overcome the elastic force of the tangential spring 5, causing the control ring 6 to lag angularly relative to the input gear 1.

[0030] As an example, an elastic seal 9 is provided at the opening of the annular liquid storage cavity. The fixed end of the seal 9 is interference-fitted with the slot of the electromagnetic stator assembly 3, and abuts against the root circumferential surface of the shear boss 603 of the control ring 6 in a dynamic sealing manner.

[0031] The output gear 2 and input gear 1 have a composite guide design on their opposite end faces: the output gear 2 is positioned opposite to the input gear 1, and its contact end face has a composite guide structure formed by a circumferential buffer track 201 and a radial locking V-groove 202. For example... Figure 5 As shown, the output gear 2 and the input gear 1 have a cylindrical protrusion 203 on their opposite end faces. A composite guide structure is provided on the cylindrical protrusion 203. The circumferential buffer track 201 is an annular groove provided on the end face of the cylindrical protrusion 203. Several radial locking V grooves 202 are evenly distributed circumferentially on the end face of the cylindrical protrusion 203. The radial locking V grooves 202 are arranged radially along the cylindrical protrusion 203 and have a V-shaped cross-section. The radial locking V grooves 202 penetrate the cylindrical protrusion 203 radially.

[0032] The dimensions of the low-position reset surface 6011 and the high-position locking surface 6013 on the control ring 6, as well as the dimensions of the axial guide hole 103 on the input gear 1 and the radial locking V-groove 202 on the output gear 2, satisfy the following: When the transmission ball 4 is located at the low reset surface 6011 on the control ring 6, the transmission ball 4 is located within the low reset surface 6011 of the control ring 6 and the axial guide hole 103 of the input gear 1, and its front end does not protrude from the input gear 1. At this time, the input gear 1 and the output gear 2 are separated, that is, the clutch gear is in a disengaged state. When the transmission ball 4 is located at the high locking surface 6013 on the control ring 6, the front end of the transmission ball 4 protrudes from the input gear 1. At this time, the transmission ball 4 is located within the high locking surface 6013 of the control ring 6, the axial guide hole 103 of the input gear 1, and the radial locking V groove 202 of the output gear 2. At this time, the transmission ball 4 forms a locking relationship between the control ring 6, the input gear 1, and the output gear 2, that is, the clutch gear is in a engaged state.

[0033] The working process of this clutch gear is as follows: (1) Initial state: Initially, the clutch gear is in the disengaged state. At this time, the electromagnetic stator assembly 3 is de-energized, and the low-position reset surface 6011 of the control ring 6 is aligned with the axial guide hole 103 of the input gear 1. The transmission ball 4 is located in the low-position reset surface 6011 of the control ring 6 and the axial guide hole 103 of the input gear 1, and its front end does not protrude from the input gear 1. At this time, the motor rotates, driving the input gear 1 to rotate, but the output gear 2 is in the disengaged state from the input gear 1, and the output gear 2 does not rotate.

[0034] (2) Power-on addressing stage: When the electromagnetic stator assembly 3 is powered on, the magnetorheological fluid 8 undergoes a rheological effect, generating a huge shear viscous resistance on the shear boss 603 of the control ring 6, causing a phase difference between the control ring 6 and the input gear 1, resulting in angular lag (at this time, the tangential spring 5 is compressed, generating force). At this time, the transmission ball 4 enters the linear transition ramp 6012 from the low-position reset surface 6011 of the control ring 6. The linear transition ramp 6012 acts as a linear ejection ramp, squeezing the tail of the transmission ball 4 and slowly ejecting it. After the front end of the transmission ball 4 protrudes, it first falls into the circumferential buffer track 201 of the output gear 2 for a brief sliding addressing, eliminating rigid impact.

[0035] (3) Locking transmission stage: As the input gear 1 rotates, the transmission ball 4 slides into the radial locking V groove 202 of the output gear 2. At this time, the tail of the transmission ball 4 is located at the position of the high locking surface 6013 of the control ring 6. Under the action of the load counter-thrust, the transmission ball 4 is firmly locked between the high locking surface 6013 and the radial locking V groove 202, forming a rigid transmission chain, driving the output gear 2 to rotate (at this time, the transmission ball 4 locks the control ring 6, the input gear 1 and the output gear 2, and the three rotate synchronously).

[0036] When an abnormal load at the output end (such as hitting a wall) causes the reverse torque to exceed the threshold, the transmission ball 4 disengages from the high-position locking surface 6013 of the control ring 6 and is squeezed out of the radial locking V groove 202. It then jumps back into the circumferential buffer track 201 and slips, thus protecting the gear from damage and achieving overload protection. At this time, under the action of mechanical force, the control ring 6 is forced to overcome the resistance of the magnetorheological fluid, and the phase difference with the input gear 1 decreases. However, the ramp inside the control ring 6 also holds the transmission ball 4 in place. When the transmission ball 4 slides to the next radial locking V groove 202, a click will be heard, and the above movement will be repeated. That is, there is a "ratchet effect" at this time, which can be used as a warning signal of overload.

[0037] When separation is required, simply de-energize the electromagnetic stator assembly 3. At this time, under the restoring force of the tangential spring 5, the control ring 6 rotates relative to the input gear 1 to its initial position, aligning the low-position reset surface 6011 of the control ring 6 with the axial guide hole 103 of the input gear 1. The transmission ball 4 falls back to the low-position reset surface 6011 and is located within the axial guide hole 103 of the input gear 1, with its front end not protruding from the input gear 1. At this time, the motor rotates, but the output gear 2 is in a separated state from the input gear 1, and the output gear 2 does not rotate.

[0038] This clutch gear utilizes the viscous resistance generated by the magnetorheological fluid 8 in the electromagnetic stator assembly 3 to cause phase lag in the control ring 6, thereby driving the transmission ball 4 to extend axially. This allows the transmission ball 4 to engage with the radial locking V-groove 202 on the output gear 2, forming a controllable locking connection. Active disengagement is achieved through the reset of the tangential spring 5, and precise overload protection can be achieved by balancing the viscous resistance of the magnetorheological fluid 8 with the wedge-shaped component force of the transmission ball 4. In addition, the end face of the output gear 2 is provided with an auxiliary circumferential buffer track 201 to optimize engagement smoothness, thereby solving the problems of traditional spring clutches that cannot be actively controlled and suffer from excessive wear due to overload.

[0039] To ensure reliable torque transmission and achieve precise overload protection, the relationship between the angle of the radial locking V-groove 202 in the composite guide structure and the torque was analyzed. For example... Figure 8 As shown, when the transmission ball 4 is locked to the side wall of the radial locking V groove 202, its mechanical balance satisfies the following relationship:

[0040] in To set the transmitted torque; The control ring 6 applies axial thrust to the transmission balls 4 via a wedge-shaped drive ramp; The effective radius of the transmission ball 4 is the distance from the center of the transmission ball 4 to the axis of the clutch shaft 7. This is the half-angle of the radially locking V-groove 202.

[0041] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A clutch gear based on rolling element locking and electromagnetic control, characterized in that, include: The clutch shaft (7), the input gear (1) coaxially mounted on the clutch shaft (7), the output gear (2) loosely fitted on both ends of the input gear (1) on the clutch shaft (7), and the control ring (6); The transmission ball (4) is movably housed in the axial guide hole (103) of the input gear (1), and can generate axial displacement under the action of the control ring (6) to realize the power engagement or disengagement between the input gear (1) and the output gear (2); The control ring (6) has a shear boss (603) inserted into the magnetorheological fluid (8), which can rotate relative to the input gear (1) at a set angle under the action of the shear viscous resistance generated by the magnetorheological fluid (8) or under the action of the restoring force of the tangential spring (5) between the control ring (6) and the output gear (2), so as to drive the transmission ball (4) to generate axial displacement.

2. The clutch gear based on rolling element locking and electromagnetic control as described in claim 1, characterized in that, On the end face of the input gear (1) facing the control ring (6), there is a groove (101) that allows the control ring (6) to be embedded. Several spring receiving grooves A (102) and several axial guide holes (103) are distributed circumferentially in the groove (101). The axial guide hole (103) is a through hole, and its effective axial length is less than the diameter of the transmission ball (4); On the end face of the control ring (6) facing the input gear (1), there are spring receiving grooves B (602) that correspond one-to-one with the spring receiving groove A (102). When the input gear (1) is fitted and assembled with the control ring (6), the spring receiving groove A (102) and the spring receiving groove B (602) arranged opposite to each other interlock to form a closed spring receiving cavity; a tangential spring (5) is provided in each spring receiving cavity; one axial end of the tangential spring (5) abuts against the end wall of the spring receiving groove A (102), and the other axial end abuts against the end wall of the opposite end of the spring receiving groove B (602).

3. The clutch gear based on rolling element locking and electromagnetic control as described in claim 2, characterized in that, On the end face of the control ring (6) facing the input gear (1), spring receiving grooves B (602) and drive grooves (601) are distributed circumferentially in an alternating manner. The drive groove (601) has a wedge-shaped drive ramp; the wedge-shaped drive ramp is formed by connecting a low-position reset surface (6011), a linear transition slope (6012) and a high-position locking surface (6013) in sequence; the end of the drive groove (601) with a smaller groove depth is provided with an arc surface as the high-position locking surface (6013) of the transmission ball (4); the end with a larger groove depth is the low-position reset surface (6011), which has an arc transition with the linear transition slope (6012).

4. The clutch gear based on rolling element locking and electromagnetic control as described in claim 3, characterized in that, The output gear (2) has a cylindrical protrusion (203) on its end face facing the input gear (1), and a number of radial locking V-grooves (202) are evenly distributed along the circumference on the end face of the cylindrical protrusion (203). When the transmission ball (4) is located at the position of the low-position reset surface (6011) on the control ring (6), the transmission ball (4) is located in the axial guide hole (103) between the low-position reset surface (6011) and the input gear (1), and the clutch gear is in a disengaged state at this time. When the transmission ball (4) is located at the high locking surface (6013) on the control ring (6), the transmission ball (4) is located in the high locking surface (6013), the axial guide hole (103) of the input gear (1) and the radial locking V groove (202). The transmission ball (4) makes the control ring (6), the input gear (1) and the output gear (2) form a locking relationship. At this time, the clutch gear is in the engaged state.

5. The clutch gear based on rolling element locking and electromagnetic control as described in claim 4, characterized in that, On the end face of the cylindrical protrusion (203) of the output gear (2), a circumferential buffer track (201) is provided along the circumferential direction, and the circumferential buffer track (201) is connected to the radial locking V groove (202).

6. The clutch gear based on rolling element locking and electromagnetic control as described in any one of claims 1-5, characterized in that, The back of the control ring (6) is provided with an annular protrusion as a shearing boss (603). The shearing boss (603) is inserted into the annular liquid storage cavity of the electromagnetic stator assembly (3) and forms a uniform micro shear gap between it and the inner and outer walls of the annular liquid storage cavity. The annular liquid storage cavity is filled with magnetorheological fluid (8).

7. The clutch gear based on rolling element locking and electromagnetic control as described in claim 6, characterized in that, The opening of the annular liquid storage cavity is provided with a sealing element (9), which abuts against the root circumferential surface of the shear boss (603) of the control ring (6) in a dynamic sealing manner.

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