Motor lead screw buffering type gear shifting mechanism suitable for electric drive assembly of commercial vehicle

Abstract

The invention discloses a motor lead screw buffer type gear shifting mechanism suitable for an electric drive assembly of a commercial vehicle. The motor lead screw buffer type gear shifting mechanism comprises a shell, a lead screw internally provided with a screw pair sleeve and a nut, and the nut moves in the first direction relative to the lead screw; a shifting groove is formed in the gear shifting shifting piece, the nut laterally extends to form a convex part, and a first buffer block and a second buffer block are arranged on the opposite sides of the convex part in the first direction. The total size of the convex part, the first buffer block and the second buffer block in the first direction is smaller than the size of the shifting groove in the first direction; the first buffer block and the second buffer block directly face the opposite faces of the shifting groove in the first direction respectively. The lead screw rotates to drive the nut to move, the nut is combined with the first buffer block and the second buffer block to push and apply force to the gear shifting piece, and the gear shifting piece drives an external synchronizer to conduct gear shifting operation. When the tooth abutting phenomenon occurs, impact force is transmitted to the buffer block through the gear shifting piece and is absorbed by deformation of the buffer block, stress on the lead screw is avoided, the service life and precision are effectively guaranteed, and gear shifting smoothness is improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle transmission technology, and in particular to a motor screw buffer shifting mechanism suitable for electric drive assemblies of commercial vehicles. Background Technology

[0002] In the two-speed shifting mechanism of electric drive assembly of new energy vehicles and electric drive axle assembly of commercial vehicles, the transmission method of ball screw pair, shift fork mechanism and synchronizer is usually adopted. The screw in ball screw pair rotates and drives nut to move linearly. The moving nut drives shift fork in shift fork mechanism to move linearly. Shift fork drives synchronizer to move linearly. The tooth sleeve in synchronizer meshes with the outer engagement tooth on one of the two sides of the movement direction to complete the shift.

[0003] While the existing shifting mechanisms are relatively mature and low-cost, achieving absolute and perfect synchronization between the synchronizer and the engaging teeth during shifting is extremely difficult due to factors such as the accuracy of the speed sensor, motor control response delay, and system inertia. When a speed difference exists between the two, a "tooth collision" phenomenon occurs, where the end face teeth of the sleeve collide head-on with the end face teeth of the engaging teeth instead of meshing smoothly, resulting in impact on the shifting mechanism during shifting. Under such repeated, high-intensity impact loads, the lifespan and accuracy of the ball screw pair are severely challenged. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a reasonably structured motor lead screw buffer shifting mechanism suitable for commercial vehicle electric drive assemblies. When tooth misalignment occurs, the impact force is transmitted to the buffer block via the shift paddle, where it is absorbed by the deformation of the buffer block, thus preventing the lead screw from being stressed and effectively ensuring service life and accuracy.

[0005] The technical solution adopted in this invention is as follows: A motor lead screw buffer-type shifting mechanism suitable for electric drive assemblies of commercial vehicles includes a housing, in which a lead screw is installed, and a nut is fitted onto the lead screw via a helical pair. The nut moves relative to the lead screw in a first direction. It also includes a shift paddle with a shift groove, and a protrusion extending laterally from the nut. Buffer blocks one and two are respectively arranged on opposite sides of the protrusion in the first direction. The protrusion, buffer blocks one, and buffer blocks two extend together into the shift groove. The total dimension of the protrusion, buffer blocks one, and buffer blocks two in the first direction is smaller than the dimension of the shift groove in the first direction. Buffer blocks one and buffer blocks two are respectively positioned opposite the opposing sides of the shift groove in the first direction.

[0006] As a further improvement to the above technical solution: The buffer block one and buffer block two extend outwards on opposite sides in the first direction to form convex structures, and the end faces of the convex structures form a mating surface facing the groove.

[0007] The bonding surface is provided with a concave-convex structure, which includes, but is not limited to, toothed structure and wave structure.

[0008] The bottom surface of the groove is set as a planar structure one, and the protrusion, buffer block one, and buffer block two are provided with a planar structure two, which is arranged directly opposite to the planar structure one.

[0009] The first planar structure and the second planar structure form a gap of less than 1 mm.

[0010] The shift paddle extends toward the lead screw to form a shifting part. Two shifting parts are spaced apart in the first direction, and a shifting groove is formed between the two shifting parts. A U-shaped groove is formed on each shifting part. At least one end of the nut extends in the first direction to form a guide part, which is adapted to the U-shaped groove of the shifting part.

[0011] One end of the nut is a guide portion with a smaller radial dimension, and the other end of the nut is a protrusion with a larger radial dimension.

[0012] The nut has a convex part with a large radial dimension in the middle, and guide parts with a smaller radial dimension at both ends of the nut located on both sides of the convex part.

[0013] It also includes a shift fork shaft mounted on the housing, and a shift paddle slidably mounted on the shift fork shaft; the shift paddle moves relative to the shift fork shaft in a first direction.

[0014] It also includes a shift motor installed inside the housing, which is powered by the lead screw.

[0015] Compared with the prior art, the present invention has the following beneficial effects: During use, the rotation of the lead screw drives the nut to move. The nut, together with buffer block one and buffer block two, pushes and applies force to the shift paddle. The shift paddle drives the external synchronizer to perform shifting operation. When tooth collision occurs, the impact force is transmitted to the buffer block through the shift paddle and absorbed by the deformation of the buffer block, thus effectively avoiding the stress on the helical pair between the lead screw and the nut, thereby greatly ensuring service life and transmission accuracy, and improving the smoothness of shifting. The present invention also includes the following advantages: Buffer block one and buffer block two are set on both sides of the nut protrusion. The overall structure is compact, occupies little space, and has a high degree of integration. It can effectively reduce and improve the contact noise between buffer block one and buffer block two and the object, and help improve the noise and vibration of the whole vehicle. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the present invention (Example 1).

[0017] Figure 2This is a structural diagram of the present invention (Embodiment 2, omitting the housing and shift motor).

[0018] Figure 3 for Figure 2 A sectional view.

[0019] The components include: 1. Shift motor; 2. Housing; 3. Lead screw; 4. Buffer block one; 5. Buffer block two; 6. Nut; 7. Shift fork shaft; 8. Shift lever; 51. Outwardly convex structure; 52. Adhesive surface; 61. Protrusion; 62. Guide section; 80. Actuating part; 81. Gutter; X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0020] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0021] like Figure 1 , Figure 2 and Figure 3 As shown in the figure, a motor lead screw buffer-type shifting mechanism suitable for electric drive assemblies of commercial vehicles in this embodiment includes a housing 2, a lead screw 3 installed inside the housing 2, a nut 6 mounted on the lead screw 3 via a helical pair, and the nut 6 moving relative to the lead screw 3 in a first direction X; it also includes a shift paddle 8, which has a shift groove 81, and a protrusion 61 extending laterally from the nut 6. Buffer blocks 4 and 5 are respectively provided on opposite sides of the protrusion 61 in the first direction X; the protrusion 61, buffer blocks 4, and buffer blocks 5 together extend into the shift groove 81, and the total size of the protrusion 61, buffer blocks 4, and buffer blocks 5 in the first direction X is smaller than the size of the shift groove 81 in the first direction X; the buffer blocks 4 and buffer blocks 5 are respectively directly opposite the opposite sides of the shift groove 81 in the first direction X.

[0022] During use, the rotation of the lead screw 3 drives the nut 6 to move. The nut 6, together with the buffer block 4 and the buffer block 5, pushes and applies force to the shift paddle 8. The shift paddle 8 drives the external synchronizer to perform shifting operation. When a tooth collision occurs, the impact force will be transmitted to the buffer block, such as the buffer block 4 or the buffer block 5, through the shift paddle 8. The buffer block will be absorbed by deformation, thus effectively avoiding hard contact between the nut 6 and the shift paddle 8 and avoiding stress on the helical pair between the lead screw 3 and the nut 6.

[0023] In actual gear shifting, the nut 6 will move along the lead screw 3 in the first direction X, and one of the buffer block 4 or the buffer block 5 will apply force to the side of the shift groove 81, thereby driving the shift paddle 8 to move in the first direction X to shift gears.

[0024] In this embodiment, buffer block 4 and buffer block 5 are provided on both sides of the protrusion 61 of nut 6. The overall structure is compact, occupies little space, and has a high degree of integration. It can effectively reduce and improve the contact noise between buffer block 4 and buffer block 5 and the object, which helps to improve the noise and vibration of the whole vehicle.

[0025] In this embodiment, buffer block 4 and buffer block 5 can be made of conventional materials with buffering properties, such as TPE (Thermoplastic Elastomer) plastic material. During normal gear shifting, it can act as a rigid part to apply force to the shift paddle 8, and can deform to absorb the impact force when impacts such as top teeth occur, and quickly recover its shape when the impact force is removed.

[0026] Buffer block 4 and buffer block 5 extend from opposite sides in the first direction to form convex structures 51, and the end face of the convex structure 51 forms a mating surface 52 facing the groove 81.

[0027] In this embodiment, by setting the convex structure 51, the contact area of ​​the shift paddle 8 by the buffer block 4 or the buffer block 5 during the shifting process is effectively reduced. The contact surface 52 applies force close to the side of the shift groove 81, which helps to ensure the smooth and stable transmission of force. At the same time, by reducing the contact area, when collisions such as tooth collisions occur, the deformation of the buffer block 4 and the buffer block 5 can effectively absorb the impact of the collision. After the collision is removed, the deformation can be restored quickly and smoothly, thus effectively avoiding structural jamming caused by the deformation of the buffer block 4 and the buffer block 5.

[0028] The mating surface 52 is provided with a concave-convex structure, including but not limited to toothed structure and wave structure, which helps to lift and ensure that the force applied between the buffer block 1 4, the buffer block 2 5 and the side wall of the groove 81 is effective, reliable and smooth.

[0029] The bottom surface of the groove 81 is set as a planar structure one, and the protrusion 61, buffer block one 4, and buffer block two 5 are provided with a planar structure two, which is arranged directly opposite to the planar structure one.

[0030] In this embodiment, by setting the planar structure one and the planar structure two facing each other, during the rotation of the lead screw 3, the planar structure one and the planar structure two will form a limit to prevent the nut 6 from rotating with the lead screw 3, so that the rotation of the lead screw 3 can smoothly drive the nut 6 to move in the first direction X, thereby realizing the smooth shifting operation.

[0031] In one embodiment, the planar structure can be located in a plane formed by a first direction X and a second direction Y.

[0032] The gap between planar structure one and planar structure two is less than 1mm, which not only limits the rotation of nut 6, but also effectively reduces the resistance to movement of nut 6 in the first direction X, ensuring smooth movement of nut 6.

[0033] In this embodiment, a gap of less than 1 mm is usually the design value, which is the gap value when planar structure one and planar structure two are in a parallel state.

[0034] The shift paddle 8 extends toward the lead screw 3 to form a shifting part 80. Two shifting parts 80 are spaced apart in the first direction X, and a shift groove 81 is formed between the two shifting parts 80. A U-shaped groove is formed on each shifting part 80. At least one end of the nut 6 extends in the first direction X to form a guide part 62, which is adapted to the U-shaped groove of the shifting part 80.

[0035] exist Figure 3 In the embodiment shown, the shift paddle 8 extends toward the lead screw 3 in the third direction Z to form a paddle portion 80. A single paddle portion 80 forms a U-shaped groove in the second direction Y. When the nut 6 moves along the first direction X, the guide portion 62 adapted in the U-shaped groove forms a guide for the movement.

[0036] exist Figure 1 In the first embodiment shown, a guide portion 62 is formed only at one end of the nut 6.

[0037] In this embodiment, one end of the nut 6 is a guide portion 62 with a smaller radial dimension, and the other end of the nut 6 is a protrusion 61 with a larger radial dimension.

[0038] In this embodiment, the buffer block 4 and buffer block 5 located on both sides of the protrusion 61 are both ring structures. One is sleeved on the guide part 62, and the other is sleeved on the lead screw 3 together with the nut 6.

[0039] exist Figure 2 and Figure 3 In the second embodiment shown, guide portions 62 are formed extending from both ends of the nut 6.

[0040] In this embodiment, the nut 6 has a convex part 61 with a larger radial dimension in the middle, and guide parts 62 with a smaller radial dimension at both ends of the nut 6 located on both sides of the convex part 61.

[0041] In this embodiment, the buffer block 4 and buffer block 5 located on both sides of the protrusion 61 are both annular structures, which are respectively sleeved on the guide portions 62 on both sides.

[0042] In actual operation, the guide parts 62 on both sides of the protrusion 61 can be set to the same radial dimension, so that the buffer block 4 and the buffer block 5 have the same structure and can be used interchangeably, which is convenient for assembly and maintenance.

[0043] It also includes a shift fork shaft 7 installed on the housing 2, and a shift paddle 8 slidably installed on the shift fork shaft 7; the shift paddle 8 moves axially relative to the shift fork shaft 7 in the first direction X.

[0044] It also includes a shift motor 1 installed inside the housing 2, which is powered by a lead screw 3.

[0045] In this embodiment, the shift motor 1 serves as the shifting power. When a shifting operation is required, the shift motor 1 works to drive the lead screw 3 to rotate, causing the nut 6 to move in the first direction X, thereby pushing the shift paddle 8 to move axially to perform the shifting.

[0046] In actual operation, the forward and reverse rotation of the shift motor 1 can drive the lead screw 3 to rotate synchronously in the forward and reverse directions, so that the nut 6 can move in the forward or reverse direction of the first direction X, thereby realizing the shifting of gears.

[0047] This invention has a compact structure and occupies little space. It effectively avoids stress on the helical pair between the lead screw and nut due to phenomena such as tooth tipping, thereby greatly ensuring service life and transmission accuracy, and improving the smoothness of gear shifting.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0049] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A motor lead screw buffer shifting mechanism suitable for electric drive assemblies of commercial vehicles, comprising a housing (2), characterized in that: The housing (2) is equipped with a lead screw (3), and a nut (6) is fitted on the lead screw (3) via a screw pair. The nut (6) moves relative to the lead screw (3) in a first direction. It also includes a shift paddle (8), which has a shift groove (81). The nut (6) has a lateral protrusion (61). Buffer block one (4) and buffer block two (5) are respectively provided on opposite sides of the protrusion (61) in the first direction. The protrusion (61), buffer block one (4), and buffer block two (5) extend into the shift groove (81). The total size of the protrusion (61), buffer block one (4), and buffer block two (5) in the first direction is smaller than the size of the shift groove (81) in the first direction. The buffer block one (4) and buffer block two (5) are respectively facing the opposite sides of the shift groove (81) in the first direction.

2. The motor screw buffer shifting mechanism for commercial vehicle electric drive assemblies as described in claim 1, characterized in that: The buffer block one (4) and buffer block two (5) extend on opposite sides in the first direction to form an outward convex structure (51), and the end face of the outward convex structure (51) forms a mating surface (52) facing the groove (81).

3. The motor lead screw buffer shifting mechanism for commercial vehicle electric drive assemblies as described in claim 2, characterized in that: The bonding surface (52) is provided with a concave-convex structure, which includes, but is not limited to, toothed structure and wave structure.

4. The motor screw buffer shifting mechanism for commercial vehicle electric drive assemblies as described in claim 1, characterized in that: The bottom surface of the groove (81) is set as a planar structure one, and the protrusion (61), buffer block one (4), and buffer block two (5) are provided with a planar structure two, which is arranged opposite to the planar structure one.

5. A motor screw buffer shifting mechanism suitable for commercial vehicle electric drive assemblies as described in claim 4, characterized in that: The planar structure one and planar structure two form a gap of less than 1 mm.

6. The motor screw buffer shifting mechanism for commercial vehicle electric drive assemblies as described in claim 1, characterized in that: The shift paddle (8) extends toward the lead screw (3) to form a paddle part (80). Two paddle parts (80) are spaced apart in the first direction, and a groove (81) is formed between the two paddle parts (80). A U-shaped groove is provided on a single paddle part (80). The nut (6) extends at least one end in the first direction to form a guide part (62), and the guide part (62) is adapted to the U-shaped groove of the paddle part (80).

7. A motor screw buffer shifting mechanism suitable for commercial vehicle electric drive assemblies as described in claim 6, characterized in that: One end of the nut (6) is a guide part (62) with a smaller radial dimension, and the other end of the nut (6) is a protrusion (61) with a larger radial dimension.

8. A motor screw buffer shifting mechanism suitable for commercial vehicle electric drive assemblies as described in claim 6, characterized in that: The nut (6) has a large radial protrusion (61) in the middle, and guides (62) with smaller radial dimensions at both ends of the nut (6) on both sides of the protrusion (61).

9. A motor screw buffer shifting mechanism suitable for commercial vehicle electric drive assemblies as described in claim 1, characterized in that: It also includes a shift fork shaft (7) mounted on the housing (2), and a shift paddle (8) slidably mounted on the shift fork shaft (7); the shift paddle (8) moves relative to the shift fork shaft (7) in a first direction.

10. A motor screw buffer shifting mechanism for a commercial vehicle electric drive assembly as described in claim 1, characterized in that: It also includes a shift motor (1) installed in the housing (2), and the shift motor (1) is powered by the lead screw (3).

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