Integrated linear steering engine

Abstract

The invention discloses an integrated linear steering engine, which belongs to the technical field of linear steering engines, and comprises a shell, and a motor assembly, a transmission assembly and a sensor which are arranged in the shell, the transmission assembly comprises a multi-stage gear pair, a lead screw pair and an output shaft assembly. The lead screw pair output shaft assembly and the motor assembly are arranged in parallel. The multi-stage gear pair comprises an input gear, a transfer gear and an output gear which are sequentially arranged in a meshed mode, and the input gear is connected with the output end of the motor assembly. The lead screw pair output shaft assembly comprises a lead screw and a nut output shaft. One end of the lead screw is connected with the output gear, the other end of the lead screw is connected with the nut output shaft, and the nut output shaft extends out of the shell to achieve linear output. The sensor comprises a rotary transformer sensor, and the rotary transformer sensor is arranged at the end, away from the output end, of the motor assembly. The size and weight of the steering engine can be greatly reduced, and the steering engine has the advantages of being large in output torque and high in transmission precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of linear servos, and particularly relates to an integrated linear servo. Background Art

[0002] In recent years, with the continuous progress of the basic industrial level and modern technology, servo systems are developing towards the design directions of miniaturization, high integration, long life, high efficiency, and maintenance-free. The research on technologies such as unmanned aerial vehicles (UAVs) and cruise guided missiles in our country has become one of the current hotspots. Due to the small size of UAVs and cruise guided missiles and the extremely high utilization rate of the internal space, the design and development difficulty of the servos required for adjusting their spatial postures or engine controls has increased.

[0003] An electric servo is an executive functional component that realizes the deflection of a rudder blade during the flight of a missile. When the servo works, the control circuit outputs torque through a motor, and a speed reduction mechanism further amplifies the torque to control the deflection of the rudder blade and realize the attitude adjustment of the missile body. Restricted by the transmission method, it is difficult for traditional electric servos to output a large torque in a narrow space. There are two common methods in the prior art. One is to increase the output torque by adopting a multi-stage gear transmission method. However, this method will increase the system error due to too many transmission links, thus affecting the accuracy of the servo. The other is to adopt the method of increasing the reduction ratio of a certain link. However, this method has problems such as a large required installation space and an increase in the mass of the servo, which restricts the miniaturization of equipment such as UAVs and cruise guided missiles.

[0004] In addition, a brushless DC motor is generally adopted in existing electric servos, and a conventional brushless DC motor uses Hall elements to control the rotation of the motor rotor. Taking a conventional three-pole brushless DC motor as an example, the control accuracy of its Hall elements is only 60 degrees, and it is impossible to accurately control the direction of the magnetic field of the permanent magnet on the servo rotor to be consistent with the magnetic field direction of the external transmitting device. Moreover, an ordinary motor controls the rotation of the motor rotor through Hall elements or an encoder. The rotation of the motor rotor is equally divided into a number of pulses in one week, and a fixed angle is rotated for one pulse. This kind of control belongs to open-loop control and cannot feedback the real-time information of the angle of the motor rotor to the servo controller, and an additional sensor needs to be used for the closed-loop control of the servo.

[0005] Therefore, how to greatly reduce the volume and weight of the servo while achieving high-power output on the basis of traditional servos and ensuring the output accuracy of the servo is a difficult problem that urgently needs to be tackled at present. Summary of the Invention

[0006] In view of one or more of the above defects or improvement requirements of the prior art, the present invention provides an integrated linear servo, which can not only greatly reduce the volume and weight of the servo, but also make the servo have the characteristics of large output torque and high transmission accuracy.

[0007] To achieve the above object, the present invention provides an integrated linear servo, which includes a housing and a motor assembly, a transmission assembly, and a sensor disposed within the housing;

[0008] The transmission assembly includes a multi-stage gear pair disposed at the output end of the motor assembly and a lead screw pair output shaft assembly connected to the multi-stage gear pair; the lead screw pair output shaft assembly and the motor assembly are arranged in parallel;

[0009] The multi-stage gear pair includes an input gear, a transfer gear, and an output gear that are sequentially meshed, and the input gear is connected to the output end of the motor assembly;

[0010] The lead screw pair output shaft assembly includes a lead screw and a nut output shaft; one end of the lead screw is connected to the output gear of the multi-stage gear pair, and the other end is connected to the nut output shaft, and the nut output shaft extends out of the housing to achieve linear output;

[0011] The sensor includes a resolver sensor, and the resolver sensor is disposed at one end of the motor assembly away from the output end.

[0012] As a further improvement of the present invention, the sensor further includes a linear position sensor, and the linear position sensor is connected to the nut output shaft of the lead screw pair output shaft assembly.

[0013] As a further improvement of the present invention, the motor assembly is a permanent magnet synchronous motor, which includes a permanent magnet motor rotating shaft and windings disposed outside thereof, and the output end of the permanent magnet motor rotating shaft is connected to the input gear;

[0014] Alternatively, the motor assembly is a DC brushless motor, and the output end of the DC brushless motor is connected to the input gear.

[0015] As a further improvement of the present invention, the resolver sensor includes a rotor and a stator disposed outside thereof, and the rotor is disposed on the permanent magnet motor rotating shaft of the permanent magnet synchronous motor or on the rotating shaft of the DC brushless motor.

[0016] As a further improvement of the present invention, a hinge interface is provided at one end of the nut output shaft away from the lead screw, and the nut output shaft is connected to the link assembly through this hinge interface; the link assembly includes a plurality of links, and the links are connected by pin shafts.

[0017] As a further improvement of the present invention, the housing includes a body with openings at both axial ends and a first cover and a second cover disposed at both axial ends of the body; the first cover is disposed at one end close to the multi-stage gear pair, and the second cover is disposed at one end close to the resolver sensor.

[0018] As a further improvement of the present invention, the second cover body has an extension portion extending out of the outer periphery of the body, and an electrical connector is provided on the extension portion for connecting to the steering gear controller, and the steering gear controller is electrically connected to the resolver sensor and the linear position sensor respectively through the electrical connector.

[0019] As a further improvement of the present invention, the diameters of the input gear, the intermediate gear and the output gear increase in sequence; the number of teeth of the input gear, the intermediate gear and the output gear increases in sequence.

[0020] As a further improvement of the present invention, a support sliding sleeve is provided between the nut output shaft and the housing.

[0021] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, the following beneficial effects are obtained:

[0022] (1) For the integrated linear steering gear of the present invention, a first-stage reduction unit is formed by a multi-stage gear pair, a second-stage reduction unit is formed by the lead screw pair output shaft assembly, and through the compact arrangement and integrated setting of the transmission part, the sensor part and the motor part, the steering gear realizes small volume and large torque output; and the resolver sensor arranged at the end of the motor can realize the closed-loop control of the motor, control the motor precision, effectively avoid the influence of the transmission gap, and thus avoid the "jitter phenomenon" easily occurring in the electric steering gear, and realize high-precision transmission.

[0023] (2) For the integrated linear steering gear of the present invention, on the basis of setting the resolver sensor, a linear position sensor is further provided on the lead screw pair output shaft assembly for collecting the zero position information of the steering gear, and converting the position information into an electric signal and feedbacking it to the steering gear controller for zero position calibration of the steering gear, so as to realize the dual-redundancy closed-loop control of the steering gear position and further ensure the control precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Structural schematic diagram of the integrated linear steering gear according to the embodiment of the present invention Figure 1 ;

[0025] Figure 2 Structural schematic diagram of the integrated linear steering gear according to the embodiment of the present invention Figure 2 ;

[0026] Figure 3 Structural schematic diagram of the integrated linear steering gear from another angle according to the embodiment of the present invention;

[0027] In all the drawings, the same reference numerals denote the same technical features, specifically: 1. housing; 2. resolver sensor; 3. motor assembly; 4. input gear; 5. intermediate gear; 6. output gear; 7. lead screw pair output shaft assembly; 8. linear position sensor; 9. connecting rod assembly; 10. electrical connector; 11. support sliding sleeve; 12. retaining ring;

[0028] 101. body; 102. first cover; 103. second cover; 301. permanent magnet motor rotating shaft; 302. winding; 701. lead screw; 702. nut output shaft; 901. connecting rod; 902. pin shaft. Detailed implementation manners

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] In the present invention, unless otherwise clearly specified or limited, terms such as "installation", "connection", "linkage", "fixation" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the internal communication between two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0034] As a preferred embodiment of the present invention, as Figures 1 to 3 shown, the integrated linear servo of the embodiment of the present invention includes a housing 1, a motor assembly 3, a transmission assembly and a sensor arranged in the housing 1; the transmission assembly includes a multi-stage gear pair arranged at the output end of the motor assembly 3 and a lead screw pair output shaft assembly 7 connected to the multi-stage gear pair. The lead screw pair output shaft assembly 7 and the motor assembly 3 are arranged in parallel. The motor assembly 3 transmits the rotational speed and torque to the lead screw pair output shaft assembly 7 through the multi-stage gear pair for linear output; the sensor includes a resolver sensor 2, and the resolver sensor 2 is arranged at one end of the motor assembly 3 away from the output end.

[0035] Specifically, the housing 1 includes a body 101 having openings at both axial ends and a first cover body 102 and a second cover body 103 arranged at both axial ends of the body 101, thereby forming a hollow accommodation space. In this embodiment, the first cover body 102 and the second cover body 103 are respectively arranged at the bottom end (the end close to the multi-stage gear pair) and the top end (the end close to the resolver sensor 2) of the body 101. By dividing the housing into multiple parts including the body and the cover, and detachably connecting the body and the cover, it is convenient to install, repair and replace the internal components. Preferably, on the peripheries extending from the four sides of the body 101 and the second cover body 103, several through holes are provided on the extending peripheries for detachable fixation with other structures.

[0036] Further, the multi-stage gear pair includes an input gear 4, an intermediate gear 5, and an output gear 6 that are sequentially meshed. The input gear 4 is connected to the output end of the motor assembly 3, and the output gear 6 is connected to the lead screw pair output shaft assembly 7. Preferably, when the gear module is the same, in order to improve the gear load-bearing capacity and increase the reduction ratio, the diameter of the latter-stage gear is larger than that of the former-stage gear, that is, the diameters of the input gear 4, the intermediate gear 5, and the output gear 6 increase in sequence. Preferably, the number of teeth of the input gear 4, the intermediate gear 5, and the output gear 6 increases in sequence; the tooth ratio of the input gear 4, the intermediate gear 5, and the output gear 6 is selected according to the actual output requirements to achieve different reduction ratios of the reducer, so as to achieve torque outputs with different amplification requirements; the greater the difference in the number of teeth between the front and rear stages of gears, the greater the reduction ratio, and the greater the output torque. Preferably, the multi-stage gear pair further includes support bearings for supporting each gear.

[0037] Further, the lead screw pair output shaft assembly 7 includes a lead screw 701 and a nut output shaft 702. One end of the lead screw 701 is connected to the output gear 6 of the multi-stage gear pair, and the other end is connected to the nut output shaft 702. The nut output shaft 702 passes through the second housing 103 and extends out of the housing 1, so as to achieve the linear output of the nut output shaft 702. More specifically, the nut output shaft 702 is a composite structure including a lead screw nut and an output shaft. The lead screw nut is threadedly connected to the lead screw 701 to convert the rotation of the lead screw 701 into the linear movement of the lead screw nut and the output shaft.

[0038] The multi-stage gear pair of the embodiment of the present invention forms a first-stage reduction unit, and the lead screw pair output shaft assembly 7 forms a second-stage reduction unit. The motor assembly 3 transmits the speed and torque to the lead screw pair output shaft assembly 7 through the multi-stage gear pair, and further realizes the amplification and linear output of the torque through the lead screw pair output shaft assembly 7. The motor assembly 3 realizes the input of torque and speed through the first-stage reduction unit and the second-stage reduction unit.

[0039] In a preferred embodiment, the sensor further includes a linear position sensor 8. The linear position sensor 8 is provided on the housing 1 and is connected to the nut output shaft 702 of the lead screw pair output shaft assembly 7 through an ear to move synchronously therewith, and is used to sense the position information of the nut output shaft 702 in real time.

[0040] Further preferably, a hinge interface is provided at the axial end of the nut output shaft 702 away from the lead screw 701. The nut output shaft 702 is connected to the link assembly 9 outside the housing 1 through this hinge interface to realize the final output of the torque. The link assembly 9 preferably includes a plurality of links 901, and the links 901 are connected by pin shafts 902. After the thrust and speed output by the lead screw 701 are transmitted to the nut output shaft 702, they are finally converted into the set speed and torque output through the link assembly 9.

[0041] Further preferably, a support sliding sleeve 11 is provided between the nut output shaft 702 and the housing 1 for supporting the nut output shaft 702, which is beneficial to improving the stability of the linear movement of the nut output shaft 702.

[0042] Further, the motor assembly in the embodiment of the present invention is a permanent magnet synchronous motor or a DC brushless motor. When the motor assembly is a permanent magnet synchronous motor, it includes a permanent magnet motor rotating shaft 301 and a winding 302 provided outside thereof, and the permanent magnet motor rotating shaft is driven to generate speed and torque through the winding; one end of the permanent magnet motor rotating shaft 301 is an output end, and the output end is connected to the input gear 4. When the motor assembly is a DC brushless motor, the output end of the DC brushless motor is connected to the input gear 4. Further, the resolver 2 includes a rotor and a stator provided outside thereof, wherein the rotor is provided on the permanent magnet motor rotating shaft 301 or the rotating shaft of the DC brushless motor, so that the rotor and the permanent magnet motor rotating shaft 301 or the rotating shaft of the DC brushless motor can rotate synchronously. Preferably, a snap ring 12 is provided between the stator of the resolver 2 and the second cover 103, which is beneficial to improving the rotational stability of the rotor.

[0043] In a preferred embodiment, the second cover 103 has an extension portion extending out of the outer periphery of the main body 101, and an electrical connector 10 is provided on the extension portion for connecting to the steering gear controller; the steering gear controller is electrically connected to the resolver 2 and the linear position sensor 8 through the electrical connector 10 respectively.

[0044] In order to exert the speed and load performance of the motor, it is usually necessary to drive the motor with a relatively large control amount, but this will cause a transmission gap in the reducer at the output end of the motor, which will affect the steering gear output shaft reaching the specified position, and the steering gear output shaft cannot stop at the specified position, that is, the "jitter phenomenon" occurs. The present invention sets a resolver 2 to sense the position information of the permanent magnet motor rotating shaft in real time, and the steering gear control signal sent by the steering gear controller, and generates a PWM square wave signal according to a certain control law with the control signal and the steering gear feedback signal, and drives the motor to rotate after power amplification by the power circuit, and realizes the linear displacement and torque output of the steering gear output shaft through the multi-stage gear pair and the lead screw pair output shaft assembly, so as to realize closed-loop control. The closed-loop control of the resolver 2 for the motor assembly 3 effectively avoids the influence of the transmission gap, thereby avoiding the "jitter phenomenon" easily occurring in the electric steering gear and realizing high-precision transmission.

[0045] The resolver sensor 2 of the present invention adopts a digital control method, which can feedback the real-time information of the motor rotor angle to the servo controller for servo closed-loop control. The closed-loop at the motor end can improve the control accuracy, and since the transmission clearance is an out-of-loop clearance, the influence of the transmission clearance on the control stiffness can be avoided. Affected by the control stiffness, the performance of the motor of a conventional servo cannot be fully exerted, while the closed-loop control using the resolver sensor 2 of the present invention can fully exert the motor performance, thus greatly improving the servo speed, dynamic response performance, etc. By performing closed-loop control at the motor end using the resolver sensor 2 of the present invention, whether it is a permanent magnet synchronous motor or a brushless DC motor, the control accuracy can be guaranteed.

[0046] The present invention can control the motor accuracy by setting the resolver sensor 2, but there are potential hazards in setting the resolver alone. For example, when the control power supply fails abnormally and loses power, as the voltage of the control power supply drops, the control chip fails and the servo is in an uncontrolled state; but at this time, the drive circuit will have a certain amount of current remaining due to the influence of the capacitor, resulting in the servo continuing to deflect a certain angle; and at this time, the resolver sensor 2 has insufficient voltage and cannot work properly, and cannot record the change of the angle, resulting in a certain deviation of the zero position of the servo after power-on again.

[0047] Therefore, in the preferred embodiment of the present invention, on the basis of setting the resolver sensor 2, a linear position sensor 8 is further set on the output shaft assembly 7 of the lead screw pair for collecting the zero position information of the servo, and the position information is converted into an electrical signal and feedback to the servo controller for servo zero position calibration, so as to realize the dual-redundancy closed-loop control of the servo position.

[0048] It should be noted that both the resolver sensor 2 and the linear position sensor 8 of the present invention can achieve independent closed-loop control, and their coordinated action can form a dual-redundancy closed-loop control to solve the control hazards existing when setting the resolver sensor 2 alone.

[0049] It should be noted that in the motor assembly 3, the lengths and diameters of the permanent magnet motor rotating shaft 301 and the winding 302 are selected according to the actual output requirements to achieve the speed and torque output under different powers. And in the output shaft assembly 7 of the lead screw pair, the lengths of the lead screw 701 and the nut output shaft 702 are set according to the needs to amplify the motor rotation input into a large torque linear output that meets the control requirements.

[0050] The integrated linear servo of the present invention integrates the motor part, the transmission part, and the sensor part inside the housing, and the motor assembly and the output shaft assembly of the lead screw pair are arranged in parallel, which can minimize the volume of the linear servo and is particularly suitable for installation in flat and annular spaces. At the same time, a first-stage reduction unit is formed by a multi-stage gear pair, and a second-stage reduction unit is formed by the output shaft assembly of the lead screw pair. The cooperation of the two-stage reduction units is adopted to achieve the output of small volume and large torque of the servo. The closed-loop control of the servo at the motor assembly is realized by the resolver sensor arranged at the motor end, which can effectively avoid the influence of the transmission gap on the servo control system, thereby avoiding the "jitter phenomenon" easily occurring in the electric servo. Further, redundancy control is carried out by the linear position sensor synchronously installed on the nut output shaft. Through the synergistic effect, compact arrangement and integrated setting of the above units, not only the volume and weight of the servo are greatly reduced, but also the servo has the characteristics of large output torque and high transmission accuracy.

[0051] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An integrated linear servo, characterized in that: It includes a housing and a motor assembly, a transmission assembly and a sensor arranged in the housing; The transmission assembly comprises a multi-stage gear pair arranged at the output end of the motor assembly, and a screw pair output shaft assembly connected to the multi-stage gear pair; the screw pair output shaft assembly and the motor assembly are arranged in parallel; The multi-stage gear pair comprises an input gear, a transfer gear and an output gear which are meshed in sequence, and the input gear is connected to the output end of the motor assembly; The screw pair output shaft assembly comprises a screw and a nut output shaft; One end of the lead screw is connected to the output gear of the multi-stage gear pair, and the other end is connected to the nut output shaft, and the nut output shaft extends out of the housing to achieve linear output; The sensor comprises a resolver sensor, and the resolver sensor is arranged at an end of the motor component away from the output end.

2. The integrated linear servo according to claim 1, characterized in that: The sensor also includes a linear position sensor, which is connected to the nut output shaft of the screw auxiliary output shaft assembly.

3. The integrated linear servo according to claim 1 or 2, characterized in that: The motor assembly is a permanent magnet synchronous motor, comprising a permanent magnet motor shaft and a winding arranged outside the permanent magnet motor shaft, and the output end of the permanent magnet motor shaft is connected to the input gear; Alternatively, the motor assembly is a brushless DC motor, and an output end of the brushless DC motor is connected to the input gear.

4. The integrated linear servo according to claim 3, characterized in that: The resolver sensor comprises a rotor and a stator arranged outside the rotor, and the rotor is arranged on a permanent magnet motor shaft of a permanent magnet synchronous motor, or on a shaft of a brushless DC motor.

5. The integrated linear servo according to any one of claims 1, 2 and 4, characterized in that: An end of the nut output shaft away from the lead screw is provided with a hinge interface, and the nut output shaft is connected to the connecting rod assembly through the hinge interface; the connecting rod assembly includes a plurality of connecting rods, and the connecting rods are connected by pins.

6. The integrated linear servo according to claim 2, characterized in that: The housing includes a main body with openings at both axial ends and a first cover body and a second cover body arranged at both axial ends of the main body; the first cover body is arranged at one end close to the multi-stage gear pair, and the second cover body is arranged at one end close to the resolver sensor.

7. The integrated linear servo according to claim 6, characterized in that: The second cover body has an extension portion extending out of the periphery of the main body, and an electrical connector is provided on the extension portion for connecting with a steering gear controller. The steering gear controller is electrically connected to the resolver sensor and the linear position sensor respectively through the electrical connector.

8. The integrated linear servo according to any one of claims 1, 2, 4, 6 and 7, characterized in that: The diameters of the input gear, the intermediate gear and the output gear increase sequentially; the number of teeth of the input gear, the intermediate gear and the output gear increases sequentially.

9. The integrated linear servo according to any one of claims 1, 2, 4, 6 and 7, characterized in that: A supporting sleeve is arranged between the nut output shaft and the housing.

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