Planetary roller force transmission mechanism and brake device with easy friction rolling and clearance compensation

Abstract

The present invention provides a planetary roller force transmission mechanism and electric brake device with easy friction rolling and clearance compensation, which solves the problems that the existing electronic mechanical brake system screw and nut are easy to fail to achieve rolling friction, the processing accuracy requirement is high, the screw is easy to slip, and the working noise increases. The mechanism includes a hollow input shaft, a planetary carrier, an output shaft, an expansion ring and N planetary roller assemblies, each planetary roller assembly includes a planetary shaft and a planetary roller; the planetary carrier is arranged in the hollow input shaft; the N planetary shafts are arranged on the planetary carrier along the circumferential direction, and there is a radial gap between the planetary shaft and the planetary carrier; the hollow input shaft is provided with an internal thread or an internal annular convex groove, and the planetary roller is provided with a matching external thread or an external annular convex groove; two expansion rings are respectively located on the outer side of the two end surfaces of the planetary carrier, each expansion ring is formed by N inwardly opening outer rings and N outwardly opening inner rings staggered and connected end to end, and the ends of the N planetary shafts are respectively clamped in the N inner rings of the expansion ring; the output shaft is arranged at the front of the planetary carrier.

Description

Technical Field

[0001] The invention relates to a planetary roller force transmission mechanism and an electric brake device, and in particular to a planetary roller force transmission mechanism with easy friction rolling and clearance compensation and an electric brake device with easy friction rolling and clearance compensation. Background Art

[0002] With the rapid development of automobile technology, especially the development of new energy vehicles and autonomous driving, the continuous increase in traffic density and the gradual increase in vehicle speed, people have higher and higher requirements for the safety and reliability of automobiles. Whether the automobile braking system can realize the driver's braking intention in real time, quickly and effectively has become a key issue affecting road traffic safety.

[0003] The traditional hydraulic brake system is mainly composed of a brake pedal, a brake master cylinder, a vacuum booster, a brake wheel cylinder, and a brake. When the driver steps on the brake pedal, the hydraulic oil is pressed from the brake master cylinder to the brake wheel cylinder through the hydraulic pipeline under the assistance of the vacuum booster, and acts on the brake caliper or brake shoe, and presses against the brake disc or brake drum to achieve vehicle braking. However, the hydraulic brake system has many defects, such as complex system, and the braking force needs to pass through the vacuum booster, hydraulic pipeline, etc., resulting in slow response speed, large size, difficulty in layout and assembly on the whole vehicle, complex ABS electronic control system, and high manufacturing and maintenance costs.

[0004] The electronic mechanical brake system (EMB) not only overcomes the inherent defects of the hydraulic brake system, but also has outstanding advantages such as simple system, fast braking response speed and high efficiency. At present, the electronic mechanical brake system includes a driving mechanism, a conversion mechanism and a braking force output element. The conversion mechanism adopts a screw and a nut to realize the conversion of the rotational motion output by the driving mechanism into the translational motion of the braking force output element, thereby realizing the vehicle driving brake. Since the screw and the nut are threaded, after working for a period of time, the thread is easy to wear, making the screw easy to slip, and rolling friction cannot be achieved, affecting the braking process; and due to the processing error between the screw and the nut, the friction between the threads after assembly is insufficient, and rolling friction cannot be achieved, affecting the braking process. In order to ensure the friction between the screw and the nut, the processing accuracy of the screw and the nut is required to be high; in addition, after the thread of the screw and the nut is worn, the gap between the screw and the nut increases, resulting in increased working noise. Summary of the invention

[0005] In order to solve the technical problems that in the existing electronic mechanical braking system, the threads of the screw and the nut are easily worn during operation, which makes the screw easy to slip and affects the braking process; the screw and the nut are easily unable to achieve rolling friction due to processing errors, and in order to ensure rolling friction, high processing accuracy is required; and the working noise increases due to the wear of the threads of the screw and the nut, the present invention provides a planetary roller force transmission mechanism and an electric braking device with easy friction rolling and clearance compensation.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] A planetary roller force transmission mechanism that is easy to frictionally roll and compensate for clearance, the special features of which are:

[0008] It includes a hollow input shaft, a planet carrier, an output shaft, two expansion rings and N planet roller assemblies, where N is an integer greater than 1; each planet roller assembly includes a planet shaft and a planet roller arranged on the planet shaft;

[0009] The planet carrier is coaxially arranged in the hollow input shaft;

[0010] The N planetary shafts of the N planetary roller assemblies are arranged on the planetary frame along the circumferential direction, and both ends extend out of the planetary frame, and there is a radial gap between each planetary shaft and the planetary frame, which is used to compensate for the gap between the planetary roller and the hollow input shaft;

[0011] The inner side surface of the hollow input shaft is provided with an internal thread, and each planetary roller is provided with an external thread matching the internal thread of the hollow input shaft;

[0012] Alternatively, the inner side surface of the hollow input shaft is provided with an internal thread, each planetary roller is provided with an outer annular convex groove matching with the internal thread of the hollow input shaft, and the plurality of planetary rollers are sequentially staggered along the axial direction of the hollow input shaft;

[0013] Alternatively, the inner side surface of the hollow input shaft is provided with an inner annular convex groove, each planetary roller is provided with an outer thread matching with the inner annular convex groove of the hollow input shaft, and the plurality of planetary rollers are sequentially staggered along the axial direction of the hollow input shaft;

[0014] Two expansion rings are respectively located outside the two end surfaces of the planet carrier. Each expansion ring is formed by N outer rings opening inwards and N inner rings opening outwards, which are staggered and connected end to end. The ends of the N planetary shafts are respectively clamped in the N inner rings of the expansion ring, and the planetary rollers can rotate on the planet carrier. The minimum diameter of the circle where the centers of the N inner rings of each expansion ring are located is greater than the minimum diameter of the circle where the N planetary shafts are located.

[0015] The output shaft is arranged on the front end surface of the planet carrier, and the front end thereof extends out of the hollow input shaft.

[0016] Furthermore, the N planetary shafts of the N planetary roller assemblies are evenly distributed on the planet carrier along the circumferential direction;

[0017] Each planetary roller is provided with an outer annular convex groove matched with the internal thread of the hollow input shaft, and a plurality of planetary rollers are sequentially staggered along the axial direction of the hollow input shaft, specifically: each planetary roller is provided with an outer annular convex groove matched with the internal thread of the hollow input shaft, and the axial distance between adjacent planetary rollers along the hollow input shaft is 1 / N of the pitch of the internal thread of the hollow input shaft, where N is the number of planetary roller assemblies;

[0018] Each planetary roller is provided with an external thread that cooperates with the inner annular convex groove of the hollow input shaft, and multiple planetary rollers are staggered in sequence along the axial direction of the hollow input shaft. Specifically, each planetary roller is provided with an external thread that cooperates with the inner annular convex groove of the hollow input shaft, and the axial distance between adjacent planetary rollers along the hollow input shaft is 1 / N of the pitch of the external thread of the planetary roller, and N is the number of planetary roller assemblies.

[0019] Assume that the minimum diameter of the circle where the centers of the N inner rings of each expansion ring are located is D1, and the minimum diameter of the circle where the N planetary axes are located is D2, D = D1-D2, and the value of D meets the following requirements:

[0020] 0<D≤D3, D3 is the deformation of the expansion ring.

[0021] Furthermore, the planet carrier is provided with N radial waist-shaped holes or N U-shaped opening grooves radially opening on the outer side of the planet carrier for mounting N planet shafts;

[0022] The cross-section of the output shaft is a circular or non-circular surface; or, the hollow input shaft is provided with a limiting groove, and the output shaft is provided with a limiting protrusion or limiting rib that can slide axially in the limiting groove; or, the output shaft is provided with a limiting groove, and the hollow input shaft is provided with a limiting protrusion or limiting rib that can slide axially in the limiting groove.

[0023] Further, the planet carrier is an I-shaped structure, which includes a front planet carrier body, a rear planet carrier body, and a connecting rod arranged between the middle of the front planet carrier body and the middle of the rear planet carrier body; a plurality of planet rollers are arranged on the outer periphery of the connecting rod;

[0024] Alternatively, the planet carrier is a squirrel cage structure, which includes a front planet carrier body, a rear planet carrier body, and a squirrel cage sleeve arranged between the front planet carrier body and the rear planet carrier body; a plurality of planet rollers are located in the squirrel cage sleeve, and the planet rollers can be engaged with the internal thread or the inner annular convex groove of the hollow input shaft;

[0025] Alternatively, the planetary carrier is an I-shaped squirrel cage structure, which includes a front planetary carrier body, a rear planetary carrier body, a squirrel cage sleeve arranged between the front planetary carrier body and the rear planetary carrier body, and a connecting rod arranged between the middle part of the front planetary carrier body and the middle part of the rear planetary carrier body, and a plurality of planetary rollers are arranged on the outer periphery of the connecting rod and are located in the squirrel cage sleeve, and the planetary rollers can engage with the internal thread or inner annular convex groove of the hollow input shaft.

[0026] Furthermore, each planetary shaft is provided with an automatic centering mechanism, which includes a spherical centering unit and a second thrust bearing which is sleeved on the planetary shaft and located between the planetary carrier and the planetary roller;

[0027] The spherical centering unit comprises a spherical seat and a spherical projection which cooperate to form a spherical pair;

[0028] Bearings are arranged between the planetary shafts and the planetary rollers.

[0029] Meanwhile, the present invention also provides an electric brake device for easy friction rolling and clearance compensation, which is special in that it comprises a housing, a driving motor and a planetary roller force transmission mechanism arranged in the housing;

[0030] The planetary roller force transmission mechanism comprises a hollow input shaft, a planet carrier, an output shaft, two expansion rings and N planetary roller assemblies, where N is an integer greater than 1; each planetary roller assembly comprises a planetary shaft and a planetary roller arranged on the planetary shaft;

[0031] The driving motor drives the hollow input shaft to rotate;

[0032] The planet carrier is coaxially arranged in the hollow input shaft;

[0033] The N planetary shafts of the N planetary roller assemblies are arranged on the planetary frame along the circumferential direction, and both ends extend out of the planetary frame, and there is a radial gap between each planetary shaft and the planetary frame, which is used to compensate for the gap between the planetary roller and the hollow input shaft;

[0034] The inner side surface of the hollow input shaft is provided with an internal thread, and each planetary roller is provided with an external thread matching the internal thread of the hollow input shaft; preferably, the plurality of planetary roller assemblies are evenly distributed along the same circumference;

[0035] Alternatively, the inner side surface of the hollow input shaft is provided with an internal thread, each planetary roller is provided with an outer annular convex groove matched with the internal thread of the hollow input shaft, and a plurality of planetary rollers are sequentially staggered along the axial direction of the hollow input shaft; preferably, the plurality of planetary roller assemblies are evenly distributed around the circumference, and the axial distance between adjacent planetary rollers along the hollow input shaft is 1 / N of the pitch of the internal thread of the hollow input shaft, where N is the number of planetary roller assemblies;

[0036] Alternatively, the inner side surface of the hollow input shaft is provided with an inner annular convex groove, each planetary roller is provided with an external thread matched with the inner annular convex groove of the hollow input shaft, and a plurality of planetary rollers are sequentially staggered along the axial direction of the hollow input shaft; preferably, the plurality of planetary roller assemblies are evenly distributed around the circumference, and the axial distance between adjacent planetary rollers along the hollow input shaft is 1 / N of the pitch of the external thread of the planetary roller, where N is the number of planetary roller assemblies;

[0037] Two expansion rings are respectively located outside the two end surfaces of the planet carrier. Each expansion ring is formed by N outer rings opening inwards and N inner rings opening outwards, which are staggered and connected end to end. The ends of the N planetary shafts are respectively clamped in the N inner rings of the expansion ring, and the planetary rollers can rotate on the planet carrier. The minimum diameter of the circle where the centers of the N inner rings of each expansion ring are located is greater than the minimum diameter of the circle where the N planetary shafts are located along the radial direction.

[0038] The output shaft is arranged on the front end surface of the planet carrier, and the front end of the output shaft is supported by the housing and extends out of the housing.

[0039] Furthermore, the planet carrier is provided with N radial waist-shaped holes or N U-shaped opening grooves opened on the outer side of the planet carrier for mounting N planet shafts;

[0040] The cross-section of the output shaft is a circular or non-circular surface; or, the hollow input shaft is provided with a limiting groove, and the output shaft is provided with a limiting protrusion or limiting rib that can slide axially in the limiting groove; or, the output shaft is provided with a limiting groove, and the hollow input shaft is provided with a limiting protrusion or limiting rib that can slide axially in the limiting groove.

[0041] Further, the planet carrier is an I-shaped structure, which includes a front planet carrier body, a rear planet carrier body, and a connecting rod arranged between the middle of the front planet carrier body and the middle of the rear planet carrier body; a plurality of planet rollers are arranged on the outer periphery of the connecting rod;

[0042] Alternatively, the planet carrier is a squirrel cage structure, which includes a front planet carrier body, a rear planet carrier body, and a squirrel cage sleeve arranged between the front planet carrier body and the rear planet carrier body; a plurality of planet rollers are located in the squirrel cage sleeve, and the planet rollers can be engaged with the internal thread or the inner annular convex groove of the hollow input shaft;

[0043] Alternatively, the planetary carrier is an I-shaped squirrel cage structure, which includes a front planetary carrier body, a rear planetary carrier body, a squirrel cage sleeve arranged between the front planetary carrier body and the rear planetary carrier body, and a connecting rod arranged between the middle part of the front planetary carrier body and the middle part of the rear planetary carrier body, and a plurality of planetary rollers are arranged on the outer periphery of the connecting rod and are located in the squirrel cage sleeve, and the planetary rollers can engage with the internal thread or inner annular convex groove of the hollow input shaft.

[0044] Furthermore, each planetary shaft is provided with an automatic centering mechanism, which includes a spherical centering unit and a second thrust bearing which is sleeved on the planetary shaft and located between the planetary carrier and the planetary roller;

[0045] The spherical centering unit comprises a spherical seat and a spherical projection which cooperate to form a spherical pair;

[0046] Bearings are arranged between the planetary shafts and the planetary rollers.

[0047] Further, the housing comprises a front end cover, an intermediate housing and a rear cover which are connected in sequence;

[0048] The hollow input shaft is a cylindrical structure with an open front end, and its front end dynamic seal is arranged on the front end cover;

[0049] The front end cover is provided with a through hole for the output shaft to extend out, and a dynamic sealing structure is provided between the front end cover and the output shaft.

[0050] The dynamic sealing structure comprises a sliding sleeve and a sealing ring, wherein the sliding sleeve is arranged in the through hole of the front end cover, and the sealing ring is arranged between the sliding sleeve and the output shaft and between the sliding sleeve and the front end cover;

[0051] The bearing is a radial bearing.

[0052] Furthermore, the intermediate shell has a connecting plate inside, dividing the inner cavity of the shell into a front cavity and a rear cavity;

[0053] The drive motor and the planetary roller force transmission mechanism are both located in the front cavity, the motor rotor of the drive motor is a hollow structure, and the hollow input shaft of the planetary roller force transmission mechanism is coaxially fixed in the motor rotor;

[0054] A magnet fixing shaft supported on a connecting plate is provided in the middle of the rear end surface of the hollow input shaft, and an induction magnet is provided at the rear end of the magnet fixing shaft;

[0055] A circuit board is provided in the rear cavity, and a magnetic sensing element is provided on the circuit board at a position opposite to the sensing magnet;

[0056] A clutch lock mechanism is provided on the outer side of the hollow input shaft for realizing separation and locking of the hollow input shaft.

[0057] Compared with the prior art, the advantages of the present invention are:

[0058] 1. The planetary roller force transmission mechanism of the present invention uses an expansion ring to fix the planetary shaft to the planetary carrier. The expansion ring is used to apply a pressing force to the planetary roller to prevent the planetary roller from sliding on the meshing surface and causing abnormal wear of the meshing surface, thereby affecting the transmission efficiency and service life.

[0059] 2. During the operation of the planetary roller force transmission mechanism of the present invention, when the threads on the planetary roller and the hollow input shaft are worn, the expansion ring can expand the planetary shaft outward to ensure that the external thread of the planetary roller and the internal thread of the hollow input shaft (or the external thread of the planetary roller and the inner annular convex groove of the hollow input shaft or the external annular convex groove of the planetary roller and the inner thread of the hollow input shaft) are fully meshed, the thread wear is supplemented, and the transmission efficiency is ensured; at the same time, due to the effect of the expansion ring, the processing accuracy and assembly accuracy requirements of the planetary shaft and the planetary carrier are greatly reduced, thereby reducing the manufacturing cost; it also avoids the noise problem caused by the increase in the gap between the planetary roller and the hollow input shaft.

[0060] 3. The planetary roller force transmission mechanism of the present invention adopts a planetary roller mechanism (a planetary carrier and multiple planetary roller assemblies), which can achieve a larger braking force output with a smaller structure, which makes the device easy to install and ensures high-efficiency braking force output (high transmission efficiency, the contact line is better than ball point contact, and can withstand a larger load). The electric brake device of the present invention has the characteristics of compact structure, large output braking force, easy installation and high reliability.

[0061] 4. The motor rotor of the present invention is designed as a hollow structure, and the braking force transmission mechanism is built into the hollow part of the motor rotor, which fully utilizes the limited space and reduces the volume of the electric brake device.

[0062] 5. The electric brake device of the present invention can realize the self-locking of the mechanism when power is off through the clutch lock locking mechanism to achieve the parking brake function, thereby integrating the functions of driving brake and parking brake.

[0063] 6. The present invention uses an expansion ring to fix the planetary shaft to the planetary carrier. The expansion ring can expand the planetary shaft outward to ensure transmission efficiency. Therefore, the electric brake device has lower requirements on the processing accuracy and assembly accuracy of the planetary roller mechanism (planetary carrier and multiple planetary roller assemblies) and the hollow input shaft, making the processing simpler and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a structural schematic diagram of Embodiment 1 of the electric brake device for easy friction rolling and clearance compensation of the present invention;

[0065] Figure 2a The three-dimensional structure diagram of the planetary roller force transmission mechanism in the first embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention Figure 1 (hollow input shaft not shown);

[0066] Figure 2b Schematic diagram 2 of the three-dimensional structure of the planetary roller force transmission mechanism in the first embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention (the hollow input shaft is not shown);

[0067] Figure 3 yes Figure 2a A schematic diagram of the structure in one direction;

[0068] Figure 4 yes Figure 2a A cross-sectional view of

[0069] Figure 5 It is a structural schematic diagram of the clutch lock locking mechanism in the first embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention;

[0070] Figure 6 It is a structural schematic diagram of the automatic centering mechanism in the first embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention;

[0071] Figure 7a It is a three-dimensional structural schematic diagram of the planetary roller force transmission mechanism in the second embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention (the hollow input shaft is not shown);

[0072] Figure 7b yes Figure 7a A schematic diagram of the structure in one direction;

[0073] Figure 8 It is a structural schematic diagram of the automatic centering mechanism in the third embodiment of the electric brake device with easy friction rolling and clearance compensation of the present invention;

[0074] Fig. 9 It is a structural schematic diagram of Embodiment 5 of the electric brake device with easy friction rolling and clearance compensation of the present invention;

[0075] The reference numerals are as follows:

[0076] 1-front cover, 2-middle housing, 3-rear cover, 4-motor stator, 5-motor rotor, 6-first thrust bearing, 7-output shaft, 71-rear planetary carrier, 72-front planetary carrier, 73-squirrel cage sleeve, 8-hollow input shaft, 81-internal thread, 82-magnet fixed shaft, 9-planetary roller, 91-external thread, 10-planetary shaft, 11-induction magnet, 12-sleeve, 13-fixing screw, 14-circuit Plate, 15-drive motor, 16-electromagnetic brake, 17-locking fixed ring, 18-locking outer ring, 19-friction plate, 20-dynamic pressure plate, 21-second thrust bearing, 22-spherical bump, 23-spherical seat, 24-first adjusting gasket, 25-second adjusting gasket, 26-bearing, 27-expansion ring, 271-outer ring, 272-inner ring, 28-connecting plate, 29-reducer, 291-reducer housing. DETAILED DESCRIPTION

[0077] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0078] Embodiment 1

[0079] like Figure 1 As shown, an electric brake device with easy friction rolling and clearance compensation includes a housing and a drive motor 15 arranged in the housing, a planetary roller force transmission mechanism, a control unit and a clutch lock locking mechanism.

[0080] The shell includes a front cover 1, an intermediate shell 2 and a rear cover 3 connected in sequence. The intermediate shell 2 has a connecting plate 28, which divides the inner cavity of the shell into a front cavity and a rear cavity. The front cover 1 is provided with fixing screws 13 to facilitate the fixed connection between the electric brake device of this embodiment as a whole and the wheel end of the external vehicle.

[0081] The drive motor 15 is arranged in the front cavity. The drive motor 15 consists of a motor stator 4 and a motor rotor 5. The motor stator 4 is fixed on the front end cover 1. In this embodiment, the motor rotor 5 is designed as a hollow structure, and the braking force transmission mechanism is built into the hollow part of the motor rotor 5, which makes full use of the limited space and reduces the volume of the electric braking device.

[0082] The planetary roller force transmission mechanism comprises a hollow input shaft 8, a planet carrier, an output shaft 7, two expansion rings 27 and N planetary roller assemblies, where N is an integer greater than 1; the hollow input shaft 8 is coaxially arranged in the motor rotor 5, the outer wall of the hollow input shaft 8 is fixedly connected to the inner wall of the motor rotor 5, and both ends of the outer circle side of the hollow input shaft 8 can be directly or indirectly fixed to the front end cover 1 through the first thrust bearing 6; the hollow input shaft 8 can be driven to rotate by the motor rotor 5; the hollow input shaft 8 is a cylindrical structure with an open front end, and the front end dynamic seal is arranged on the front end cover 1; the inner side of the hollow input shaft 8 is provided with an internal thread 81;

[0083] The planet carrier is coaxially arranged at the rear side of the hollow input shaft 8 by means of clearance fit; N planetary roller assemblies are circumferentially arranged on the planet carrier, and preferably, the multiple planetary roller assemblies are evenly distributed along the same circumference;

[0084] Each planetary roller assembly includes a planetary shaft 10 arranged on the planetary carrier and a planetary roller 9 arranged on the planetary shaft 10, then N planetary rollers 9 are respectively installed on the planetary carrier through N planetary shafts 10, and both ends of each planetary shaft 10 extend out of the planetary carrier, and the outer cylindrical surface of each planetary roller 9 is provided with an external thread 91 meshing with the internal thread 81 of the hollow input shaft 8; there is a radial gap between each planetary shaft 10 and the planetary carrier, which is used to compensate for the gap between the planetary roller 9 and the hollow input shaft 8. Specifically, in this embodiment, N radial waist-shaped holes arranged circumferentially are provided on the planetary carrier, and the N planetary shafts 10 are respectively arranged in the N radial waist-shaped holes, and the planetary shaft 10 can move radially along the planetary carrier in the radial waist-shaped holes.

[0085] like Figure 3 and Figure 4As shown, two expansion rings 27 are respectively located on the outer side of the two end surfaces of the planet carrier, and each expansion ring 27 is formed by N outer rings 271 opening inwardly and N inner rings 272 opening outwardly and cooperating with the planet shaft, which are staggered and connected end to end. The ends of the N planet shafts are respectively clamped in the N inner rings 272 of the expansion ring 27, and the planet roller 9 can rotate on the planet carrier; in this embodiment, at least one bearing 26 is provided between the planet roller 9 and the planet shaft 10, and the bearing is a radial bearing. The planet shaft and the planet carrier are fixed by the expansion ring 27, so that the planet roller 9 can only rotate around the planet shaft 10; in other embodiments, the planet roller 9 can be fixedly connected to the planet shaft 10, and a bearing is provided between the planet shaft 10 and the inner ring 272 of the expansion ring 27 to realize the rotation of the planet roller 9 and the planet shaft 10 on the planet carrier.

[0086] In order to facilitate the clamping of the planetary shaft and the inner ring 272 of the expansion ring 27, an opening mechanism may be provided on the expansion ring 27. The minimum diameter of the circle where the centers of the N inner rings 272 of each expansion ring 27 are located is greater than the minimum diameter of the circle where the N planetary shafts are located. Specifically, the minimum diameter of the circle where the centers of the N inner rings 272 of each expansion ring 27 are located is D1, and the minimum diameter of the circle where the N planetary shafts 10 are located is D2, D = D1-D2, and the value of D meets the following requirements: 0 < D ≤ D3, D3 is the deformation of the expansion ring 27, and the deformation determines the magnitude of the pressing force applied by the expansion ring 27 to the planetary roller; usually D satisfies: 0 < D ≤ 0.1 mm.

[0087] The output shaft 7 is arranged on the front end face of the planetary carrier, and the front end of the output shaft 7 extends out of the front end cover 1. In order to realize the translation of the output shaft 7, the cross-section of the output shaft is designed as a non-circular surface in this embodiment. In other embodiments, an axial limit groove may also be provided on the hollow input shaft, and a limit protrusion or a limit rib capable of axially sliding in the limit groove may be provided on the output shaft, or an axial limit groove may be provided on the output shaft, and a limit protrusion or a limit rib capable of axially sliding in the limit groove may be provided on the hollow input shaft.

[0088] A dynamic sealing structure is arranged between the front end cover 1 and the output shaft 7, and the dynamic sealing structure includes a sleeve 12 and a sealing ring. A through hole is arranged on the front end cover 1 for the output shaft 7 to extend out, and the sleeve 12 is arranged in the through hole of the front end cover 1. The sealing ring is arranged between the sleeve 12 and the output shaft 7 and between the sleeve 12 and the front end cover 1, and is mainly used for sealing the front end cover 1 and guiding the output shaft 7. In order to improve the guiding effect, the sleeve 12 can be a metal or non-metal sleeve.

[0089] like Figure 2a and Figure 2bAs shown, the planet carrier of this embodiment is a hollow structure, which includes a front planet carrier body 72, a rear planet carrier body 71 and a squirrel cage sleeve 73 arranged between the front planet carrier body 72 and the rear planet carrier body 71. There are four planet roller assemblies, and the four planet rollers 9 are located in the squirrel cage sleeve 73. The planet rollers 9 can mesh with the internal threads 81 on the inner side of the hollow input shaft 8. In order to improve the rigidity and stability of the planet carrier connection, a connecting rod is provided between the middle part of the front planet carrier body 72 and the middle part of the rear planet carrier body 71. The front planet carrier body 72, the rear planet carrier body 71, the connecting rod, the squirrel cage sleeve 73 and the output shaft 7 are an integral whole, but the cross-section of the output shaft is a non-circular surface. Such an arrangement allows the planet rollers 9 to only rotate on their own but not revolve. The rotation of the hollow input shaft 8 and the helix angle on its inner wall will only drive the planet carrier and the output shaft 7 to translate forward and backward along the axial direction of the output shaft 7, while the planet carrier and the output shaft 7 cannot rotate. In other embodiments, the planet carrier may be an I-shaped structure, which includes a front planet carrier body 72, a rear planet carrier body 71, and a connecting rod arranged between the middle of the front planet carrier body 72 and the middle of the rear planet carrier body 71, and a plurality of planet rollers 9 are evenly distributed on the periphery of the connecting rod.

[0090] like Figure 6 As shown, the planetary shaft 10 of this embodiment is equipped with an automatic centering mechanism, which includes a spherical centering unit and a second thrust bearing 21 which are arranged in sequence from front to back between the front planetary carrier body 72 and the front end surface of the planetary roller 9. The spherical centering unit includes a tiltable spherical seat 23 and a tiltable spherical protrusion 22 which cooperate to form a spherical pair. The spherical protrusion 22 is arranged adjacent to the second thrust bearing 21. The spherical centering unit is used to adjust the planetary roller 9 and the planetary shaft 10 to always be on the same axis, thereby reducing the force loss during the transmission process.

[0091] like Figure 1 As shown, the control unit includes an induction magnet 11 and a circuit board 14. The rear end of the hollow input shaft 8 is provided with a magnet fixing shaft 82 supported on the connecting plate 28, and the induction magnet 11 is arranged on the magnet fixing shaft 82; the circuit board 14 is arranged on the intermediate shell 2 and is located in the rear cavity. A magnetic sensing element is provided on the circuit board 14 at a position relative to the induction magnet 11. The magnetic sensing element can identify the strength of the radial N / S level magnetic field of the induction magnet 11 during movement. The circuit board 14 is used to analyze and calculate the stroke of the translational movement of the output shaft 7 and perform real-time control.

[0092] like Figure 5As shown, the clutch lock locking mechanism is arranged on the outer side of the rear end of the hollow input shaft 8, and the clutch lock locking mechanism is mainly composed of an electromagnetic brake 16, a locking fixed ring 17, a locking outer ring 18, a friction plate 19 and a dynamic pressure plate 20. The electromagnetic brake 16 is fixed on the intermediate housing 2, one end of the dynamic pressure plate 20 is in contact with or close to the electromagnetic brake 16, and the other end is close to or in contact with the friction plate 19. A plurality of springs are arranged in the electromagnetic brake 16, one end of which is in contact with the electromagnetic brake 16 itself, and the other end is in contact with the dynamic pressure plate 20; the other end of the friction plate 19 is in contact with or close to the inner wall of the locking outer ring 18, the outer ring and the inner ring of the locking fixed ring 17 are both provided with splines, the inner ring splines are meshed with the splines arranged on the outer wall of the hollow input shaft 8, and the outer ring splines are meshed with the splines arranged on the inner ring of the friction plate 19. The clutch lock locking mechanism can realize the separation and locking of the hollow input shaft 8 respectively by energizing or de-energizing the electromagnetic brake 16.

[0093] The braking action process of the electric brake device in this embodiment is as follows:

[0094] During driving, when the driver steps on the brake pedal, the drive motor 15 starts, and the motor rotor 5 drives the hollow input shaft 8 to rotate. The rotation of the hollow input shaft 8 drives multiple planetary rollers 9 to rotate. Since the cross-section of the output shaft 7 is a non-circular surface, the planetary rollers 9 can only rotate around the planetary shaft 10. Furthermore, the planetary rollers 9 push the planetary carrier and the output shaft 7 to translate forward along the axial direction of the output shaft 7. The force output member at the front end of the output shaft 7 is fixedly connected to the vehicle brake pad, thereby realizing vehicle driving braking.

[0095] The electric brake device of this embodiment uses an expansion ring 27 to fix the planetary shaft to the planetary carrier. During operation, when the threads on the planetary rollers and the hollow input shaft are worn, the expansion ring 27 can expand the planetary shaft outward to ensure that the external threads of the planetary rollers and the internal threads of the hollow input shaft are fully engaged, replenish the thread wear, and ensure transmission efficiency; it also avoids the noise problem caused by the increase in the gap between the planetary rollers and the hollow input shaft, thereby increasing the service life.

[0096] Embodiment 2

[0097] The difference from the first embodiment is that: Figure 7a and Figure 7b As shown, N radial waist-shaped holes arranged on the planet carrier open on the outer side of the planet carrier, forming N U-shaped opening grooves opening on the outer side of the planet carrier, which is convenient for the installation of the planetary roller assembly.

[0098] Embodiment 3

[0099] The difference from the first embodiment is that: Figure 8As shown, each planetary roller 9 is provided with an outer annular convex groove matched with the internal thread 81 of the hollow input shaft 8, and each planetary shaft 10 is also provided with a first adjusting gasket 24 and a second adjusting gasket 25, the first adjusting gasket 24 is located between the front planetary carrier body 72 and the spherical seat 23, and the second adjusting gasket 25 is located between the rear end face of the planetary roller 9 and the rear planetary carrier body 71, and by adjusting the thickness of the first adjusting gasket 24 and the second adjusting gasket 25, multiple planetary rollers 9 are sequentially staggered along the axial direction of the hollow input shaft 8, and preferably multiple planetary roller assemblies are evenly distributed around the circumference, then the adjacent planetary rollers 9 differ in the axial direction of the hollow input shaft 8 by 1 / N of the pitch of the internal thread of the hollow input shaft, N being the number of planetary roller assemblies, so as to realize the threaded engagement of multiple planetary rollers 9 with the helix angle of the inner wall of the hollow input shaft 8 in the axial direction, and the outer annular convex groove of the planetary roller 9 can be a straight line or arc tooth profile matching the tooth profile of the hollow input shaft 8. In other embodiments, the first adjusting gasket 24 and the second adjusting gasket 25 may be implemented by bosses provided on the planet carrier.

[0100] Embodiment 4

[0101] The difference from the third embodiment is that an inner annular convex groove is provided on the inner side surface of the hollow input shaft 8, and each planetary roller 9 is provided with an external thread 91 that cooperates with the inner annular convex groove of the hollow input shaft 8. By adjusting the thickness of the first adjustment gasket 24 and the second adjustment gasket 25, the difference between adjacent planetary rollers along the axial direction of the hollow input shaft is 1 / N of the pitch of the external threads of the planetary rollers, so that the external threads of multiple planetary rollers 9 are axially meshed with the inner annular convex groove of the inner wall of the hollow input shaft 8.

[0102] Embodiment 5

[0103] The difference from the first to fourth embodiments is that: Fig. 9 As shown, the drive motor 15 is located on the outside of the shell, and the rear end of the hollow input shaft 8 of the braking force transmission mechanism extends out of the shell and is connected to the drive motor 15 through the reducer 29; the control unit is not shown in the figure, and the rear end of the hollow input shaft 8 is provided with a magnet fixing shaft 82 supported on the reducer housing 291, and the induction magnet 11 of the control unit is arranged on the magnet fixing shaft 82; the circuit board 14 is arranged on the outside of the shell, and a magnetic sensing element is provided on the circuit board 14 at a position relative to the induction magnet 11. The magnetic sensing element can identify the strength of the radial N / S level magnetic field of the induction magnet 11 during the movement, and the circuit board 14 is used to analyze and calculate the stroke of the translational movement of the output shaft 7 and perform real-time control.

[0104] The above is only a description of the preferred implementation mode of the present invention, and the technical solution of the present invention is not limited thereto. Any modification made by those skilled in the art on the basis of the main technical concept of the present invention belongs to the technical scope to be protected by the present invention.

Claims

1. A planetary roller force transmission mechanism with easy friction rolling and clearance compensation, characterized in that: It comprises a hollow input shaft (8), a planet carrier, an output shaft (7), two expansion rings (27), and N planet roller assemblies, where N is an integer greater than 1; each planet roller assembly comprises a planet shaft (10) and a planet roller (9) arranged on the planet shaft (10); The planet carrier is coaxially arranged inside the hollow input shaft (8); The N planetary shafts (10) of the N planetary roller assemblies are arranged on the planetary frame along the circumferential direction, and both ends extend out of the planetary frame, and a radial gap exists between each planetary shaft (10) and the planetary frame, which is used to compensate for the gap between the planetary roller (9) and the hollow input shaft (8); The inner side surface of the hollow input shaft (8) is provided with an internal thread (81), and each planetary roller (9) is provided with an external thread (91) matching with the internal thread (81) of the hollow input shaft (8); Alternatively, the inner side surface of the hollow input shaft (8) is provided with an internal thread (81), each planetary roller (9) is provided with an outer annular convex-concave groove matching the internal thread (81) of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8); Alternatively, the inner side surface of the hollow input shaft (8) is provided with an inner annular convex groove, each planetary roller (9) is provided with an outer thread (91) that matches the inner annular convex groove of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8); Two expansion rings (27) are respectively located outside the two end surfaces of the planet carrier, each expansion ring (27) is formed by staggered end-to-end connection of N inwardly open outer rings (271) and N outwardly open inner rings (272), the ends of the N planetary shafts (10) are respectively clamped in the N inner rings (272) of the expansion ring (27), and the planetary roller (9) can rotate on the planet carrier; the minimum diameter of the circle where the centers of the N inner rings (272) of each expansion ring (27) are located is greater than the minimum diameter of the circle where the N planetary shafts (10) are located; The output shaft (7) is arranged on the front end surface of the planet carrier, and the front end thereof extends out of the hollow input shaft (8).

2. The planetary roller force transmission mechanism with easy friction rolling and clearance compensation according to claim 1, characterized in that: The N planetary shafts (10) of the N planetary roller assemblies are evenly distributed on the planetary frame along the circumferential direction; Each of the planetary rollers (9) is provided with an outer annular convex-concave groove matched with the internal thread (81) of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8), specifically: each of the planetary rollers (9) is provided with an outer annular convex-concave groove matched with the internal thread (81) of the hollow input shaft (8), and the axial distance between adjacent planetary rollers (9) along the hollow input shaft (8) is 1 / N of the pitch of the internal thread (81) of the hollow input shaft (8), where N is the number of planetary roller assemblies; Each planetary roller (9) is provided with an external thread (91) that cooperates with the inner annular convex groove of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8). Specifically, each planetary roller (9) is provided with an external thread (91) that cooperates with the inner annular convex groove of the hollow input shaft (8), and the axial distance between adjacent planetary rollers (9) along the hollow input shaft (8) is 1 / N of the pitch of the external thread (91) of the planetary roller (9), where N is the number of planetary roller assemblies.

3. The planetary roller force transmission mechanism with easy friction rolling and clearance compensation according to claim 1 or 2, characterized in that: The planet carrier is provided with N radial waist-shaped holes or N U-shaped opening grooves radially opening on the outer side of the planet carrier for mounting N planet shafts (10); The cross section of the output shaft (7) is a circular or non-circular surface; or, the hollow input shaft (8) is provided with a limiting groove, and the output shaft (7) is provided with a limiting protrusion or a limiting rib capable of axially sliding in the limiting groove; or, the output shaft (7) is provided with a limiting groove, and the hollow input shaft (8) is provided with a limiting protrusion or a limiting rib capable of axially sliding in the limiting groove.

4. The planetary roller force transmission mechanism with easy friction rolling and clearance compensation according to claim 3, characterized in that: The planet carrier is an I-shaped structure, comprising a front planet carrier body (72), a rear planet carrier body (71), and a connecting rod arranged between the middle of the front planet carrier body (72) and the middle of the rear planet carrier body (71); a plurality of planet rollers (9) are arranged on the outer periphery of the connecting rod; Alternatively, the planet carrier is a squirrel cage structure, comprising a front planet carrier body (72), a rear planet carrier body (71), and a squirrel cage sleeve (73) arranged between the front planet carrier body (72) and the rear planet carrier body (71); a plurality of planet rollers (9) are located in the squirrel cage sleeve (73), and the planet rollers (9) can mesh with the internal thread (81) or the inner annular convex groove of the hollow input shaft (8); Alternatively, the planet carrier is an I-shaped squirrel cage structure, which includes a front planet carrier body (72), a rear planet carrier body (71), a squirrel cage sleeve (73) arranged between the front planet carrier body (72) and the rear planet carrier body (71), and a connecting rod arranged between the middle part of the front planet carrier body (72) and the middle part of the rear planet carrier body (71), a plurality of planetary rollers (9) are arranged on the outer periphery of the connecting rod and are located in the squirrel cage sleeve (73), and the planetary rollers (9) can engage with the internal thread (81) or the inner annular convex groove of the hollow input shaft (8).

5. The planetary roller force transmission mechanism with easy friction rolling and clearance compensation according to claim 4, characterized in that: Each planetary shaft (10) is provided with an automatic centering mechanism, which comprises a spherical centering unit and a second thrust bearing (21) which is sleeved on the planetary shaft (10) and located between the planetary carrier and the planetary roller (9); The spherical centering unit comprises a spherical seat (23) and a spherical projection (22) which cooperate to form a spherical pair; A bearing (26) is arranged between the planetary shaft (10) and the planetary roller (9).

6. An electric brake device with easy friction rolling and clearance compensation, characterized in that: It comprises a housing, a driving motor (15) and a planetary roller force transmission mechanism arranged in the housing; The planetary roller force transmission mechanism comprises a hollow input shaft (8), a planet carrier, an output shaft (7), two expansion rings (27) and N planetary roller assemblies, where N is an integer greater than 1; each planetary roller assembly comprises a planetary shaft (10) and a planetary roller (9) arranged on the planetary shaft (10); The driving motor (15) drives the hollow input shaft (8) to rotate; The planet carrier is coaxially arranged inside the hollow input shaft (8); The N planetary shafts (10) of the N planetary roller assemblies are arranged on the planetary frame along the circumferential direction, and both ends extend out of the planetary frame, and a radial gap exists between each planetary shaft (10) and the planetary frame, which is used to compensate for the gap between the planetary roller (9) and the hollow input shaft (8); The inner side surface of the hollow input shaft (8) is provided with an internal thread (81), and each planetary roller (9) is provided with an external thread (91) matching with the internal thread (81) of the hollow input shaft (8); Alternatively, the inner side surface of the hollow input shaft (8) is provided with an internal thread (81), each planetary roller (9) is provided with an outer annular convex-concave groove matching the internal thread (81) of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8); Alternatively, the inner side surface of the hollow input shaft (8) is provided with an inner annular convex groove, each planetary roller (9) is provided with an outer thread (91) that matches the inner annular convex groove of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8); Two expansion rings (27) are respectively located outside the two end surfaces of the planet carrier, each expansion ring (27) is formed by staggered end-to-end connection of N inwardly open outer rings (271) and N outwardly open inner rings (272), the ends of the N planetary shafts (10) are respectively clamped in the N inner rings (272) of the expansion ring (27), and the planetary roller (9) can rotate on the planet carrier; the minimum diameter of the circle where the centers of the N inner rings (272) of each expansion ring (27) are located is greater than the minimum diameter of the circle where the N planetary shafts (10) are located; The output shaft (7) is arranged on the front end surface of the planet carrier, and its front end is supported by the housing and extends out of the housing.

7. The electric brake device with easy friction rolling and clearance compensation according to claim 6, characterized in that: The N planetary shafts (10) of the N planetary roller assemblies are evenly distributed on the planetary frame along the circumferential direction; Each of the planetary rollers (9) is provided with an outer annular convex-concave groove matched with the internal thread (81) of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8), specifically: each of the planetary rollers (9) is provided with an outer annular convex-concave groove matched with the internal thread (81) of the hollow input shaft (8), and the axial distance between adjacent planetary rollers (9) along the hollow input shaft (8) is 1 / N of the pitch of the internal thread (81) of the hollow input shaft (8), where N is the number of planetary roller assemblies; Each planetary roller (9) is provided with an external thread (91) that cooperates with the inner annular convex groove of the hollow input shaft (8), and the plurality of planetary rollers (9) are sequentially staggered along the axial direction of the hollow input shaft (8). Specifically, each planetary roller (9) is provided with an external thread (91) that cooperates with the inner annular convex groove of the hollow input shaft (8), and the axial distance between adjacent planetary rollers (9) along the hollow input shaft (8) is 1 / N of the pitch of the external thread (91) of the planetary roller (9), where N is the number of planetary roller assemblies.

8. The electric brake device with easy friction rolling and clearance compensation according to claim 7, characterized in that: The planet carrier is provided with N radial waist-shaped holes or N U-shaped opening grooves radially opening on the outer side of the planet carrier for mounting N planet shafts (10); The cross section of the output shaft (7) is a circular or non-circular surface; or, the hollow input shaft (8) is provided with a limiting groove, and the output shaft (7) is provided with a limiting protrusion or a limiting rib capable of axially sliding in the limiting groove; or, the output shaft (7) is provided with a limiting groove, and the hollow input shaft (8) is provided with a limiting protrusion or a limiting rib capable of axially sliding in the limiting groove.

9. The electric brake device with easy friction rolling and clearance compensation according to claim 8, characterized in that: The planet carrier is an I-shaped structure, comprising a front planet carrier body (72), a rear planet carrier body (71), and a connecting rod arranged between the middle of the front planet carrier body (72) and the middle of the rear planet carrier body (71); a plurality of planet rollers (9) are arranged on the outer periphery of the connecting rod; Alternatively, the planet carrier is a squirrel cage structure, comprising a front planet carrier body (72), a rear planet carrier body (71), and a squirrel cage sleeve (73) arranged between the front planet carrier body (72) and the rear planet carrier body (71); a plurality of planet rollers (9) are located in the squirrel cage sleeve (73), and the planet rollers (9) can mesh with the internal thread (81) or the inner annular convex groove of the hollow input shaft (8); Alternatively, the planet carrier is an I-shaped squirrel cage structure, which includes a front planet carrier body (72), a rear planet carrier body (71), a squirrel cage sleeve (73) arranged between the front planet carrier body (72) and the rear planet carrier body (71), and a connecting rod arranged between the middle part of the front planet carrier body (72) and the middle part of the rear planet carrier body (71), a plurality of planetary rollers (9) are arranged on the outer periphery of the connecting rod and are located in the squirrel cage sleeve (73), and the planetary rollers (9) can engage with the internal thread (81) or the inner annular convex groove of the hollow input shaft (8).

10. The electric brake device with easy friction rolling and clearance compensation according to claim 9, characterized in that: Each planetary shaft (10) is provided with an automatic centering mechanism, which comprises a spherical centering unit and a second thrust bearing (21) which is sleeved on the planetary shaft (10) and located between the planetary carrier and the planetary roller (9); The spherical centering unit comprises a spherical seat (23) and a spherical projection (22) which cooperate to form a spherical pair; A bearing (26) is provided between the planetary shaft (10) and the planetary roller (9); The housing comprises a front cover (1), an intermediate shell (2) and a rear cover (3) which are connected in sequence; The hollow input shaft (8) is a cylindrical structure with an open front end, and a front end dynamic seal is arranged on the front end cover (1); The front end cover (1) is provided with a through hole for the output shaft (7) to extend out, and a dynamic sealing structure is provided between the front end cover (1) and the output shaft (7).

11. The electric brake device with easy friction rolling and clearance compensation according to claim 10, characterized in that: The intermediate shell (2) has a connecting plate (28) inside, dividing the inner cavity of the shell into a front cavity and a rear cavity; The drive motor (15) and the planetary roller force transmission mechanism are both located in the front cavity, the motor rotor (5) of the drive motor (15) is a hollow structure, and the hollow input shaft (8) of the planetary roller force transmission mechanism is coaxially fixed in the motor rotor (5); A magnet fixing shaft (82) supported on a connecting plate (28) is provided at the middle of the rear end surface of the hollow input shaft (8), and an induction magnet (11) is provided at the rear end of the magnet fixing shaft (82); A circuit board (14) is provided in the rear cavity, and a magnetic sensing element is provided on the circuit board (14) at a position opposite to the sensing magnet (11); A clutch lock mechanism is provided on the outer side of the hollow input shaft (8) for realizing separation and locking of the hollow input shaft (8).

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