Permanent magnet synchronous linear motor

Abstract

Disclosed in the present disclosure is a permanent magnet synchronous linear motor, comprising a housing, a rotor, and a lead screw module, wherein the rotor is arranged in the housing, and the rotor is of a hollow structure; and the lead screw module comprises a main lead screw and planetary rollers, the main lead screw is movably located in the hollow structure of the rotor, one end of the main lead screw movably passes through the housing and extends out of the housing, and the planetary rollers are configured to be in threaded connection with the hollow structure of the rotor and the main lead screw. During use, the rotor drives the planetary rollers to rotate during rotation, so as to convert the rotation of the rotor into a linear motion of the main lead screw.

Description

Permanent magnet synchronous linear motor

[0001] The present disclosure claims priority to the Chinese patent application No. 202421422684.X, filed on June 20, 2024, and entitled "Permanent magnet synchronous linear motor", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to, but are not limited to, the motor technical field, and particularly relate to a permanent magnet synchronous linear motor. BACKGROUND

[0003] Permanent magnet synchronous linear motors mainly include two types. One type is to drive a slider to move linearly on a sliding rail support or a flexible cable support through electromagnetic interaction between a coil winding and a permanent magnet. The other type is to realize linear motion through a rotating motor plus a planetary roller screw. However, these two design methods will result in a large size of the permanent magnet synchronous linear motor.

[0004] CONTENT OF THE UTILITY MODEL

[0005] The present disclosure provides a small permanent magnet synchronous linear motor. The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of protection of the claims.

[0006] The present disclosure provides a small permanent magnet synchronous linear motor. The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of protection of the claims.

[0007] As an optional implementation, in the present disclosure, the permanent magnet synchronous linear motor further comprises a guide sleeve, the guide sleeve is arranged at the front end of the machine shell, the guide sleeve is provided with a guide hole matched with the main lead screw, and the main lead screw is movably arranged in the guide hole.

[0008] As an optional implementation, in the present disclosure, the permanent magnet synchronous linear motor further comprises a ball bearing, a four-point contact ball bearing and a bearing sleeve, the ball bearing sleeve is arranged at the front end of the rotating shaft of the rotor, the bearing sleeve is arranged at the rear end of the rotating shaft of the rotor, and the four-point contact ball bearing is arranged on the bearing sleeve.

[0009] As an optional implementation, in the embodiment of the present disclosure, the shell comprises a main shell and a front cover, the front cover covers the front end of the main shell, the front cover is provided with a front cover stopper, the ball bearing is limited by the front cover stopper, and the ball bearing and the front cover stopper have a floating gap.

[0010] As an optional implementation, in the embodiment of the present disclosure, the shell comprises a main shell and a transition ring, the transition ring is arranged to be connected with the rear end of the main shell, the permanent magnet synchronous linear motor further comprises a bearing pressing plate, the bearing pressing plate is located at the rear end of the rotating shaft of the rotor to limit the bearing sleeve, the inner ring of the four-point contact ball bearing is clamped between the bearing pressing plate and the bearing sleeve, and the outer ring of the four-point contact ball bearing is clamped between the transition ring and the main shell.

[0011] As an optional implementation, in the embodiment of the present disclosure, the permanent magnet synchronous linear motor further comprises a position detection device arranged at the rear end of the shell, the position detection device is arranged to detect the absolute position vector of the permanent magnet synchronous linear motor and the motor rotating number of the permanent magnet synchronous linear motor.

[0012] As an optional implementation, in the embodiment of the present disclosure, the position detection device comprises a center gear set, an edge gear set, a first encoder and a second encoder, the center gear set is arranged to be connected with the rotor, the center gear set rotates synchronously with the rotor under the driving of the rotor, the first encoder is arranged to measure the position of the center gear set, the edge gear set is engagedly connected to the center gear set, and the second encoder is arranged to measure the position of the edge gear set.

[0013] The modulus of the edge gear set is same as that of the center gear set, and the number of teeth is different.

[0014] As an optional implementation, in the embodiment of the present disclosure, the center gear set comprises a first gear, a first position magnet and a first shielding magnetic ring, the first position magnet is embedded in the first gear, the first shielding magnetic ring is arranged outside the first gear, and the first encoder is a detection chip for sensing the first position magnet; the edge gear set comprises a second gear, a second position magnet and a second shielding magnetic ring, the second position magnet is embedded in the second gear, the second shielding magnetic ring is arranged outside the second gear, and the second encoder is a detection chip for sensing the second position magnet.

[0015] As an optional implementation, in the embodiment of the present disclosure, the shell comprises a rear cover, the permanent magnet synchronous linear motor further comprises a driver, and a strain gauge is attached to the rear cover. The rear cover elastically deforms under the action of the push-pull force, so that the resistance value of the strain gauge changes. The driver calculates the push-pull force of the motor through the resistance value of the strain gauge.

[0016] As an optional implementation, in the embodiment of the present disclosure, the rotor comprises a rotating shaft, a plurality of first magnets, a plurality of second magnets, a first skeleton, at least one second skeleton, and a third skeleton. The rotating shaft is a hollow structure, and the main lead screw and the planetary roller are located in the hollow structure of the rotating shaft. The first skeleton, the at least one second skeleton, and the third skeleton are sequentially and spacedly sleeved on the rotating shaft. A plurality of first positioning spaces distributed along the circumference of the rotating shaft are arranged between the first skeleton and the second skeleton. A plurality of second positioning spaces distributed along the circumference of the rotating shaft are arranged between the second skeleton and the third skeleton. A plurality of the first magnets and a plurality of the second magnets are sequentially and alternately arranged in the plurality of first positioning spaces. A plurality of the first magnets and a plurality of the second magnets are sequentially and alternately arranged in the plurality of second positioning spaces. The magnets in the same axial direction in the first positioning space and the second positioning space are the same.

[0017] As an optional implementation, in the embodiment of the present disclosure, when the second skeleton is two or more, a plurality of third positioning spaces distributed along the circumference of the rotating shaft are arranged between the adjacent two second skeletons. A plurality of the first magnets and a plurality of the second magnets are sequentially and alternately arranged in the plurality of third positioning spaces. The magnets in the same axial direction in the third positioning space and the first positioning space are the same.

[0018] As an optional implementation, in the embodiment of the present disclosure, a plurality of first positioning protrusions uniformly distributed along the circumference of the first skeleton are arranged on the first skeleton. A plurality of second positioning protrusions uniformly distributed along the circumference of the second skeleton and corresponding to the first positioning protrusions are arranged on the second skeleton. Adjacent two first positioning protrusions and adjacent two second positioning protrusions jointly form the first positioning space.

[0019] A plurality of third positioning protrusions uniformly distributed along the circumference of the third skeleton are arranged on the third skeleton. A plurality of fourth positioning protrusions uniformly distributed along the circumference of the second skeleton and corresponding to the third positioning protrusions are arranged on the second skeleton. Adjacent two third positioning protrusions and adjacent two fourth positioning protrusions jointly form the second positioning space.

[0020] The embodiment of the present disclosure has the following beneficial effects:

[0021] The permanent magnet synchronous linear motor comprises a shell, a rotor and a screw module. The rotor is arranged in the shell and has a hollow structure. The screw module comprises a main screw rod and a planetary roller. The main screw rod is movably arranged in the hollow structure of the rotor, and one end of the main screw rod is movably arranged in the shell and extends out of the shell. The planetary roller is threadedly connected to the inner wall of the hollow structure of the rotor and the main screw rod. In use, the rotor drives the planetary roller to rotate in the process of rotation, so as to convert the rotation of the rotor into the linear motion of the main screw rod. In this way, the screw module is arranged in the hollow structure of the rotor, so that the structure of the permanent magnet synchronous linear motor is more compact, and the miniaturization design of the permanent magnet synchronous linear motor is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Fig. 1 is a structural schematic diagram of a permanent magnet synchronous linear motor in an embodiment of the present disclosure;

[0024] Fig. 2 is a sectional view of the permanent magnet synchronous linear motor in the embodiment of the present disclosure;

[0025] Fig. 3 is a structural schematic diagram of a screw module in the embodiment of the present disclosure;

[0026] Fig. 4 is a structural schematic diagram of the permanent magnet synchronous linear motor with a hidden rear cover in the embodiment of the present disclosure;

[0027] Fig. 5 is a structural schematic diagram of a driver in the embodiment of the present disclosure;

[0028] Fig. 6 is a structural schematic diagram of a rotor in the permanent magnet synchronous linear motor in the embodiment of the present disclosure;

[0029] Fig. 7 is an exploded structural schematic diagram of the rotor in the permanent magnet synchronous linear motor in the embodiment of the present disclosure;

[0030] Fig. 8 is an end view of a first magnet in the embodiment of the present disclosure.

[0031] Wherein, the reference signs have the following meanings: 1 - machine housing; 11 - front cover; 111 - front cover stop; 12 - main housing; 13 - transition ring; 14 - rear cover; 2 - rotor; 21 - rotating shaft; 211 - positioning step; 22 - first magnet; 23 - second magnet; 24 - first skeleton; 241 - first positioning protrusion; 25 - second skeleton; 251 - second positioning protrusion; 252 - fourth positioning protrusion; 26 - third skeleton; 261 - third positioning protrusion; 3 - screw module; 31 - main screw; 32 - planetary roller; 4 - guide sleeve; 41 - guide hole; 5 - ball bearing; 6 - four-point contact ball bearing; 7 - bearing sleeve; 8 - bearing pressing plate; 9 - central gear set; 91 - first gear; 92 - first position magnet; 93 - first shielding magnetic ring; 10 - edge gear set; 101 - second gear; 102 - second position magnet; 103 - second shielding magnetic ring; 20 - first encoder; 30 - second encoder; 40 - driver; 50 - strain gauge; A - position detection device. DETAILED DESCRIPTION

[0032] In order to better understand and implement, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in combination with the drawings in the embodiments of the present disclosure.

[0033] In the description of the present disclosure, it should be noted that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present disclosure and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms used in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0035] In the related art, permanent magnet synchronous linear motors mainly include two kinds. One is to set a sliding track support or a flexible cable support, to drive the sliding block to move linearly on the sliding track support or the flexible cable support through electromagnetic interaction between the coil winding and the permanent magnet. However, this design requires a special sliding track support or a flexible cable support, resulting in a large volume of the permanent magnet synchronous linear motor. The other is to realize linear motion through a rotary motor plus a planetary roller screw. However, this design often assembles two separate rotary motors and planetary roller screws together through an interface, which also results in a large volume of the permanent magnet synchronous linear motor.

[0036] Based on this, the disclosure provides a kind of permanent magnet synchronous linear motor. Please see Figure 1 to Figure 5, the exemplary embodiment of the present disclosure discloses a kind of permanent magnet synchronous linear motor, the permanent magnet synchronous linear motor of the present scheme includes shell 1, rotor 2 and screw module 3, rotor 2 is located in shell 1, rotor 2 is hollow structure, screw module 3 includes main screw rod 31 and planetary roller 32, main screw rod 31 can be movably located in the hollow structure of rotor 2, one end is movably arranged in shell 1 and extends to the outside of shell 1, planetary roller 32 is threadedly connected to the inner wall of the hollow structure of rotor 2, and planetary roller 32 is threadedly connected to main screw rod 31, in use, rotor 2 rotates in the process and drives planetary roller 32 to rotate, to convert the rotation of rotor 2 into the linear motion of main screw rod 31. With such design, since screw module 3 is arranged in the hollow structure of rotor 2, the structure of the whole permanent magnet synchronous linear motor is more compact, which is beneficial to the miniaturization design of permanent magnet synchronous linear motor.

[0037] Wherein, suppose the thread length in rotor 2 is L, the length of planetary roller 32 is M, and the lead is S, then the maximum number of rotations of the motor is n=(L-M) / S.

[0038] The shell 1 of the present scheme can include a front cover 11, a main housing 12, a transition ring 13 and a rear cover 14 arranged in sequence, and the front cover 11, the main housing 12, the transition ring 13 and the rear cover 14 collectively enclose a cavity for mounting the rotor 2.

[0039] In one exemplary embodiment, in order for the main screw rod 31 to convert the rotation of the planetary roller 32 into its linear motion, the main screw rod 31 can be arranged as a square rod, and the permanent magnet synchronous linear motor further includes a guide sleeve 4 arranged at the front end of the shell 1, the guide sleeve 4 is provided with a square guide hole 41 adapted to the main screw rod 31, and the main screw rod 31 is movably arranged in the guide hole 41.

[0040] In one exemplary embodiment, in order for the rotor 2 to rotate better in the shell 1, the permanent magnet synchronous linear motor can further include a ball bearing 5, a four-point contact ball bearing 6 and a bearing sleeve 7, the ball bearing 5 is sleeved on the front end of the rotating shaft 21 of the rotor 2, the bearing sleeve 7 is sleeved on the rear end of the rotating shaft 21 of the rotor 2, and the four-point contact ball bearing 6 is sleeved on the bearing sleeve 7. With such a design, the rotation of the rotor 2 relative to the shell 1 is achieved through the rolling of the ball bearing 5 and the four-point contact ball bearing 6.

[0041] In some examples, the shell 1 can include a main housing 12 and a front cover 11, the front cover 11 covers the front end of the main housing 12, the front cover 11 is provided with a front cover stop 111, the ball bearing 5 is limited by the front cover stop 111, and there is a floating gap between the ball bearing 5 and the front cover stop 111. With such a design, the ball bearing 5 can withstand radial load.

[0042] In some examples, the housing 1 can include a main housing 12 and a transition ring 13 connected to the rear end of the main housing 12, and the permanent magnet synchronous linear motor further includes a bearing pressing plate 8 located at the rear end of the rotating shaft 21 of the rotor 2 to limit the bearing sleeve 7, the inner ring of the four-point contact ball bearing 6 is clamped in the area defined by the bearing pressing plate 8 and the bearing sleeve 7, and the outer ring of the four-point contact ball bearing 6 is clamped in the area defined by the transition ring 13 and the main housing 12. In this way, the four-point contact ball bearing 6 can bear the axial thrust and radial load of the permanent magnet synchronous linear motor.

[0043] In an example embodiment, the permanent magnet synchronous linear motor further includes a position detection device A arranged at the rear end of the housing 1, which is configured to detect the absolute position vector of the permanent magnet synchronous linear motor and the motor rotation number of the permanent magnet synchronous linear motor.

[0044] In some examples, the position detection device A can include a center gear set 9, an edge gear set 10, a first encoder 20, and a second encoder 30. The center gear set 9 is connected to the rotor 2 and rotates synchronously with the rotor 2, the first encoder 20 is configured to measure the position of the center gear set 9, the edge gear set 10 is engaged with the center gear set 9, and the second encoder 30 is configured to measure the position of the edge gear set 10. In this way, the modulus of the edge gear set 10 and the center gear set 9 is the same, and the number of teeth is different. In this way, the angular velocity of the center gear set 9 and the edge gear set 10 is different, the position of the center gear set 9 can be measured by the first encoder 20, the position of the edge gear set 10 can be measured by the second encoder 30, and the multi-turn position of the motor can be calculated by comparing the position difference between the center gear set 9 and the edge gear set 10. The differential principle can be used to calibrate the extension length of the main lead screw.

[0045] In this way, the center gear set 9 is fixed on the bearing pressing plate 8, and the edge gear set 10 is fixed on the transition ring 13.

[0046] The center gear set 9 includes a first gear 91, a first position magnet 92, and a first shielding magnetic ring 93. The first position magnet 92 is embedded in the first gear 91, and the first shielding magnetic ring 93 is arranged outside the first gear 91. The first encoder 20 is configured to sense the detection chip of the first position magnet 92. The edge gear set 10 includes a second gear 101, a second position magnet 102, and a second shielding magnetic ring 103. The second position magnet 102 is embedded in the second gear 101, and the second shielding magnetic ring 103 is arranged outside the second gear 101. The second encoder 30 is configured to sense the detection chip of the second position magnet 102.

[0047] In one example embodiment, considering that the rear cover 14 will bear a thrust force to generate stress deformation when the permanent magnet synchronous linear motor is running, the permanent magnet synchronous linear motor further comprises a driver 40, and a strain gauge 50 is attached to the rear cover 14. The rear cover 14 is elastically deformed under the action of the thrust force, so that the resistance value of the strain gauge 50 changes. The driver 40 calculates the thrust force of the motor through the resistance value of the strain gauge 50. By using such a design, the integrated structure is used to replace the external thrust force sensor, which can effectively shorten the axial length of the motor, thereby facilitating the miniaturization design of the permanent magnet synchronous linear motor.

[0048] Please refer to FIGS. 6-8, in one example embodiment, the rotor 2 comprises a rotating shaft 21, a plurality of first magnets 22, a plurality of second magnets 23, a first skeleton 24, at least one second skeleton 25, and a third skeleton 26. The rotating shaft 21 is a hollow structure, and a main lead screw 31 and a planetary roller 32 are located in the hollow structure of the rotating shaft 21. The first skeleton 24, the at least one second skeleton 25, and the third skeleton 26 are sequentially and spacedly sleeved on the rotating shaft 21. A plurality of first positioning spaces distributed along the circumference of the rotating shaft 21 are arranged between the first skeleton 24 and the second skeleton 25. A plurality of second positioning spaces distributed along the circumference of the rotating shaft 21 are arranged between the second skeleton 25 and the third skeleton 26. The plurality of first magnets 22 and the plurality of second magnets 23 are sequentially and alternately arranged in the plurality of first positioning spaces and the plurality of second positioning spaces. The magnets in the same axial direction in the first positioning spaces and the second positioning spaces are the same. By using the first skeleton 24, the second skeleton 25, and the third skeleton 26 to position the axial position and the circumferential position of the first magnets 22 and the second magnets 23, the assembly deviation of the first magnets 22 and the second magnets 23 can be reduced, and the cogging torque and the pulsating torque of the permanent magnet synchronous motor can be reduced. Moreover, the production cost of the motor is reduced because the skeleton is made at a lower cost than the open mold.

[0049] The adjacent end portions of the first magnets 22 and the second magnets 23 have opposite magnetic poles.

[0050] The at least one second skeleton 25 can be one second skeleton 25 or two or more second skeletons 25. When there are two or more second skeletons 25, a plurality of third positioning spaces distributed along the circumference of the rotating shaft 21 are arranged between the adjacent two second skeletons 25. The plurality of first magnets 22 and the plurality of second magnets 23 are sequentially and alternately arranged in the plurality of third positioning spaces. The magnets in the same axial direction in the third positioning spaces and the first positioning spaces are the same. This embodiment only takes one second skeleton 25 as an example.

[0051] In an example embodiment, in order to form the first positioning space between the first skeleton 24 and the second skeleton 25, the first skeleton 24 is provided with a plurality of first positioning protrusions 241 which are uniformly distributed along the circumference of the first skeleton 24, and the second skeleton 25 is provided with a plurality of second positioning protrusions 251 which are uniformly distributed along the circumference of the second skeleton 25 and correspond to the first positioning protrusions 241, and the first positioning space is formed between two adjacent first positioning protrusions 241 and two adjacent second positioning protrusions 251.

[0052] Similarly, in order to form the second positioning space between the second skeleton 25 and the third skeleton 26, the third skeleton 26 is provided with a plurality of third positioning protrusions 261 which are uniformly distributed along the circumference of the third skeleton 26, and the second skeleton 25 is provided with a plurality of fourth positioning protrusions 252 which are uniformly distributed along the circumference of the second skeleton 25 and correspond to the third positioning protrusions 261, and the second positioning space is formed between two adjacent third positioning protrusions 261 and two adjacent fourth positioning protrusions 252.

[0053] In an example embodiment, in order to improve the fit of the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 with the shaft 21, the inner arc surface of the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 which is in contact with the shaft 21 is a circular arc surface which is adapted to the circumferential surface of the shaft 21. With this design, the inner side wall of the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 which is in contact with the shaft 21 is a circular arc surface with a diameter equal to that of the outer circle of the shaft 21, so that the contact surface of the two is completely fitted, the cooperation is more compact, and the positioning accuracy is higher.

[0054] In an example embodiment, in order to facilitate the installation of the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 on the shaft 21, the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 are in transition fit with the shaft 21.

[0055] In an example embodiment, the first magnet 22 and the first positioning space are in clearance fit in the circumferential direction of the shaft 21, and the second magnet 23 and the second positioning space are in clearance fit in the circumferential direction of the shaft 21.

[0056] In an example embodiment, since the first magnets 22 and the second magnets 23 are directly pasted on the rotating shaft 21, in order to make the first magnets 22 and the second magnets 23 have good adhesion with the rotating shaft 21, the profile of the inner arc surface of each first magnet 22 and each second magnet 23 in contact with the rotating shaft 21 is a circular arc surface matched with the circumferential surface of the rotating shaft 21. With such a design, the diameter of the circular arc is the same as the diameter of the outer circle of the pasting position of the rotating shaft 21, so that the first magnets 22 and the second magnets 23 are fully adhered to the circumferential surface of the rotating shaft 21, making the first magnets 22 and the second magnets 23 stable and improving the performance of the motor.

[0057] In an example embodiment, the inner arc surface and the outer arc surface of the first magnet 22 have an eccentricity, and the first magnet 22 is parallel magnetized; the inner arc surface and the outer arc surface of the second magnet 23 have an eccentricity, and the second magnet 23 is parallel magnetized. With such a design, the first magnet 22 and the second magnet 23 can obtain a perfect sinusoidal air gap magnetic field as much as possible, reducing the radial electromagnetic force harmonic and torque ripple.

[0058] In an example embodiment, in order to better position the above-described skeleton and magnets, one end of the rotating shaft 21 is provided with a positioning step 211, the first skeleton 24, the at least one second skeleton 25 and the third skeleton 26 are sequentially and spacedly arranged along one end to the other end of the rotating shaft 21 where the positioning step 211 is located, and the first skeleton 24 abuts against the positioning step 211. With such a design, during assembly, the first skeleton 24 is first assembled, and then the first magnets 22 and the second magnets 23 are sequentially clamped into the first positioning space, the second skeleton 25 is then assembled, and then the first magnets 22 and the second magnets 23 are sequentially assembled, and finally the third skeleton 26 is assembled.

[0059] In an example embodiment, the material of the first skeleton 24, the at least one second skeleton 25 and the second skeleton 25 is plastic material. With the plastic skeleton, the molding is easy, the energy consumption is low, and the production cost is low.

[0060] In an example embodiment, in order to fix the first magnets 22 and the second magnets 23 on the rotating shaft 21, the first magnets 22 and the second magnets 23 are pasted on the rotating shaft 21 by using special glue for magnetic steel.

[0061] The permanent magnet synchronous linear motor provided by the present disclosure is provided with

[0062] The permanent magnet synchronous linear motor comprises a shell 1, a rotor 2 and a screw module 3. The rotor 2 is arranged in the shell 1. The rotor 2 has a hollow structure. The screw module 3 comprises a main screw rod 31 and a planetary roller 32. The main screw rod 31 is movably arranged in the hollow structure of the rotor 2. One end of the main screw rod 31 is movably arranged in the shell 1 and extends out of the shell 1. The planetary roller 32 is threadedly connected to the inner wall of the hollow structure of the rotor 2 and the main screw rod 31. In use, the rotor 2 drives the planetary roller 32 to rotate in the rotating process, so as to convert the rotation of the rotor 2 into the linear motion of the main screw rod 31. The permanent magnet synchronous linear motor provided by the present application has the hollow rotor 2, the main screw rod 31 of the screw module 3 is movably arranged in the hollow structure of the rotor 2, the planetary roller 32 of the screw module 3 is arranged between the hollow structure of the rotor 2 and the main screw rod 31, the planetary roller 32 is threadedly connected to the inner wall of the hollow structure of the rotor 2 and the main screw rod 31, the rotor 2 drives the planetary roller 32 to rotate in the rotating process, so as to convert the rotation of the rotor 2 into the linear motion of the main screw rod 31. In this way, the screw module 3 is arranged in the hollow structure of the rotor 2, so that the structure of the whole permanent magnet synchronous linear motor is more compact, and the miniaturization design of the permanent magnet synchronous linear motor is facilitated.

[0063] The technical means disclosed in the present application is not limited to the above-mentioned technical means, but also includes the technical solutions composed of any combination of the above technical features. It should be pointed out that those skilled in the art can make various improvements and refinements without departing from the principle of the present application, and these improvements and refinements are also considered within the protection scope of the present application. Industrial applicability

[0064] The permanent magnet synchronous linear motor provided by the present application comprises a shell, a rotor and a screw module. The rotor is arranged in the shell. The rotor has a hollow structure. The screw module comprises a main screw rod and a planetary roller. The main screw rod is movably arranged in the hollow structure of the rotor. One end of the main screw rod is movably arranged in the shell and extends out of the shell. The planetary roller is threadedly connected to the inner wall of the hollow structure of the rotor and the main screw rod. In use, the rotor drives the planetary roller to rotate in the rotating process, so as to convert the rotation of the rotor into the linear motion of the main screw rod. In this way, the screw module is arranged in the hollow structure of the rotor, so that the structure of the whole permanent magnet synchronous linear motor is more compact, and the miniaturization design of the permanent magnet synchronous linear motor is facilitated.

Claims

1. A permanent magnet synchronous linear motor, wherein, The permanent magnet synchronous linear motor includes a housing (1), a rotor (2), and a lead screw module (3). The rotor (2) is located inside the housing (1) and has a hollow structure. The lead screw module (3) includes a main lead screw (31) and planetary rollers (32). The main lead screw (31) is movably located inside the hollow structure of the rotor (2), with one end movably passing through the housing (1) and extending to the outside of the housing (1). The planetary rollers (32) are configured to be threadedly connected to the inner wall of the hollow structure of the rotor (2) and the main lead screw (31) to convert the rotation of the rotor (2) into the linear motion of the main lead screw (31).

2. The permanent magnet synchronous linear motor according to claim 1, wherein: The permanent magnet synchronous linear motor also includes a guide sleeve (4), which is located at the front end of the housing (1). The guide sleeve (4) is provided with a guide hole (41) adapted to the main lead screw (31), and the main lead screw (31) is movably inserted through the guide hole (41).

3. The permanent magnet synchronous linear motor according to claim 1, wherein: The permanent magnet synchronous linear motor also includes a ball bearing (5), a four-point contact ball bearing (6), and a bearing sleeve (7). The ball bearing (5) is sleeved on the front end of the shaft (21) of the rotor (2), the bearing sleeve (7) is sleeved on the rear end of the shaft (21) of the rotor (2), and the four-point contact ball bearing (6) is sleeved on the bearing sleeve (7).

4. The permanent magnet synchronous linear motor according to claim 3, wherein: The housing (1) includes a main housing (12) and a front cover (11). The front cover (11) covers the front end of the main housing (12). The front cover (11) is provided with a front cover stop (111). The front cover stop (111) limits the ball bearing (5). There is a floating gap between the ball bearing (5) and the front cover stop (111).

5. The permanent magnet synchronous linear motor according to claim 3, wherein: The housing (1) includes a main housing (12) and a transition ring (13). The transition ring (13) is configured to be connected to the rear end of the main housing (12). The permanent magnet synchronous linear motor also includes a bearing pressure plate (8). The bearing pressure plate (8) is located at the rear end of the shaft (21) of the rotor (2) to limit the bearing sleeve (7). The inner ring of the four-point contact ball bearing (6) is clamped between the bearing pressure plate (8) and the bearing sleeve (7). The outer ring of the four-point contact ball bearing (6) is clamped between the transition ring (13) and the main housing (12).

6. The permanent magnet synchronous linear motor according to claim 1, wherein: The permanent magnet synchronous linear motor also includes a position detection device (A) located at the rear end of the housing (1). The position detection device (A) is configured to detect the absolute position vector of the permanent magnet synchronous linear motor and the number of rotations of the permanent magnet synchronous linear motor.

7. The permanent magnet synchronous linear motor according to claim 6, wherein: The position detection device (A) includes a central gear set (9), an edge gear set (10), a first encoder (20), and a second encoder (30). The central gear set (9) is configured to be connected to the rotor (2). The central gear set (9) rotates synchronously with the rotor (2) under the drive of the rotor (2). The first encoder (20) is configured to measure the position of the central gear set (9). The edge gear set (10) is meshed with the central gear set (9). The second encoder (30) is configured to measure the position of the edge gear set (10). The edge gear set (10) and the center gear set (9) have the same module but different number of teeth.

8. The permanent magnet synchronous linear motor according to claim 7, wherein: The central gear set (9) includes a first gear (91), a first position magnet (92), and a first shielding magnetic ring (93). The first position magnet (92) is embedded in the first gear (91), and the first shielding magnetic ring (93) is located outside the first gear (91). The first encoder (20) is a detection chip that senses the first position magnet (92). The edge gear set (10) includes a second gear (101), a second position magnet (102), and a second shielding magnetic ring (103). The second position magnet (102) is embedded in the second gear (101), and the second shielding magnetic ring (103) is located outside the second gear (101). The second encoder (30) is a detection chip that senses the second position magnet (102).

9. The permanent magnet synchronous linear motor according to claim 1, wherein: The housing (1) also includes a rear cover (14), and the permanent magnet synchronous linear motor also includes a driver (40). A strain gauge (50) is attached to the rear cover (14). The rear cover (14) undergoes elastic deformation under the action of push and pull force, so that the resistance value of the strain gauge (50) changes. The driver (40) calculates the push and pull force of the motor by the resistance value of the strain gauge (50).

10. The permanent magnet synchronous linear motor according to any one of claims 1 to 9, wherein: The rotor (2) includes a shaft (21), a plurality of first magnets (22), a plurality of second magnets (23), a first frame (24), at least one second frame (25), and a third frame (26). The shaft (21) is a hollow structure. The main lead screw (31) and the planetary rollers (32) are located inside the hollow structure of the shaft (21). The first frame (24), at least one second frame (25), and the third frame (26) are sequentially and spaced apart on the shaft (21). The first frame (24) and the second frame (25) are... A plurality of first positioning spaces are provided between the second frame (25) and the third frame (26) and are provided between the second frame (25) and the third frame (26) and are provided between the second frame (25) and the third frame (26). A plurality of first magnets (22) and a plurality of second magnets (23) are alternately arranged in the plurality of first positioning spaces and in the plurality of second positioning spaces. The magnets in the second positioning spaces and the first positioning spaces on the same axis are the same.

11. The permanent magnet synchronous linear motor according to claim 10, wherein: When there are two or more second skeletons (25), multiple third positioning spaces are provided between two adjacent second skeletons (25) and distributed circumferentially along the axis of rotation (21). Multiple first magnets (22) and multiple second magnets (23) are alternately arranged in multiple third positioning spaces. The magnets in the third positioning spaces and the first positioning spaces are the same in the same axial direction.

12. The permanent magnet synchronous linear motor according to claim 10, wherein: The first frame (24) is provided with a plurality of first positioning protrusions (241) evenly distributed along the circumference of the first frame (24), and the second frame (25) is provided with a plurality of second positioning protrusions (251) evenly distributed along the circumference of the second frame (25) and corresponding to the first positioning protrusions (241). The first positioning space is formed by two adjacent first positioning protrusions (241) and two adjacent second positioning protrusions (251). The third frame (26) is provided with a plurality of third positioning protrusions (261) evenly distributed along the circumference of the third frame (26), and the second frame (25) is provided with a plurality of fourth positioning protrusions (252) evenly distributed along the circumference of the second frame (25) and corresponding to the third positioning protrusions (261). The second positioning space is formed by two adjacent third positioning protrusions (261) and two adjacent fourth positioning protrusions (252).

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