Select shift actuator

Abstract

A shifting actuator includes a shifting shaft, a shifting sleeve, a shifting sleeve driving mechanism and a limiting component. The shifting shaft is connected to the shifting sleeve to move synchronously with the shifting sleeve. The shifting sleeve includes a screw having a first multi-thread unidirectional thread; the shifting sleeve driving mechanism includes a transmission member and a transmission member driving mechanism; the transmission member has a mounting hole, the hole wall of the mounting hole is provided with a second multi-thread unidirectional thread matching the first multi-thread unidirectional thread, the screw passes through the mounting hole and is spirally connected to the transmission member; the transmission member driving mechanism is used to drive the transmission member to rotate; the limiting component is provided with a first limiting structure and a second limiting structure, the first limiting structure is used to limit the axial movement of the transmission member, and the second limiting structure is used to limit the rotation of the shifting sleeve. The present invention will not cause transmission jamming when performing a shifting operation, and has high transmission accuracy, simple structure and low manufacturing cost.

Description

Technical Field

[0001] The invention relates to a gear shifting technology for an automobile transmission. Background Art

[0002] Figure 1 The schematic diagram of the structure of the existing gear selection and shifting actuator for automobile transmission is shown. As shown in the figure, the existing gear selection and shifting actuator includes a gear selection sleeve 108 and two crown gears 154 and 156 driving the gear selection sleeve 108. The gear selection sleeve 108 is provided with two sets of threads with opposite rotation directions, and the two crown gears are respectively engaged with one set of threads on the gear selection sleeve 108. The two crown gears can be driven to rotate, thereby driving the gear selection sleeve to translate along its axis direction.

[0003] The existing technical solution mainly has the following deficiencies:

[0004] 1. The gear selection sleeve 108 is provided with two kinds of transmission threads, positive and negative, and meshes with the crown gears 154 and 156 at the same time. Since the crown gears 154 and 156 move in opposite directions, the mechanism may be easily stuck.

[0005] 2. The transmission structure adopted in the existing technical solution has low transmission accuracy due to its structural characteristics;

[0006] 3. The gear selection sleeve 108 is provided with two kinds of transmission threads, positive and negative, which has a complex structure, is difficult to manufacture, and has high cost. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a gear selection and shifting actuator which will not cause transmission jamming during gear selection operation, and has high transmission accuracy, simple structure and low manufacturing cost.

[0008] An embodiment of the present invention provides a gear selection and shifting actuator, comprising a gear selection and shifting shaft, a gear selection sleeve and a gear selection sleeve driving mechanism; the gear selection sleeve driving mechanism is used to drive the gear selection sleeve to move axially, and the gear selection and shifting shaft is connected to the gear selection sleeve to move synchronously with the gear selection sleeve, and its characteristic is that the gear selection sleeve comprises a screw rod, and the screw rod has a first multi-thread unidirectional thread; the gear selection sleeve driving mechanism comprises a transmission member and a transmission member driving mechanism; the transmission member has a mounting hole, and the hole wall of the mounting hole is provided with a second multi-thread unidirectional thread matching the first multi-thread unidirectional thread, the screw rod passes through the mounting hole and is spirally connected to the transmission member; the transmission member driving mechanism is used to drive the transmission member to rotate; the gear selection and shifting actuator also includes a limiting component, the limiting component is provided with a first limiting structure and a second limiting structure, the first limiting structure is used to limit the axial movement of the transmission member, and the second limiting structure is used to limit the rotation of the gear selection sleeve.

[0009] In the above-mentioned gear selection and shifting actuator, the gear selection sleeve includes a mounting portion, one end of the screw rod is connected to the mounting portion; and the second limiting structure cooperates with the mounting portion to limit the rotation of the gear selection sleeve.

[0010] In the above-mentioned gear selection and shifting actuator, the second limiting structure includes a second groove extending in a direction parallel to the axis of the screw rod; the mounting portion has a radially protruding block, and the block extends into the second groove.

[0011] The present invention has at least the following advantages:

[0012] The gear selection sleeve of the present invention is connected to the gear selection sleeve driving mechanism through a multi-line one-way thread. Compared with the two-way transmission thread, the transmission jamming phenomenon will not occur. Compared with the single-line thread, the transmission accuracy is high, the structure is simple, the manufacturing cost is low, the strength of the parts can be greatly increased, the service life of the product can be extended, and the transmission lead can be large and the response is fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of an existing gear selection and shift actuator is shown.

[0014] Figure 2 A schematic structural diagram (partial cross-section) of a shift selector actuator according to a first embodiment of the present invention is shown.

[0015] Figure 3 A schematic diagram of a gear selection sleeve according to a first embodiment of the present invention is shown.

[0016] Figure 4 A schematic diagram of a transmission member according to a first embodiment of the present invention is shown.

[0017] Figure 5 A schematic diagram showing the connection between the gear selector sleeve and the transmission member according to the first embodiment of the present invention is shown.

[0018] Figure 6 A schematic diagram of a guide sleeve according to a first embodiment of the present invention is shown.

[0019] Figure 7 A schematic diagram of the cooperation between the shift selector sleeve and the guide sleeve according to the first embodiment of the present invention is shown.

[0020] Figure 8 A schematic diagram of the cooperation between the shift selector sleeve, the shift selector sleeve driving mechanism and the guide sleeve according to the first embodiment of the present invention is shown.

[0021] Fig. 9 A schematic structural diagram of a gear selection and shifting actuator according to a second embodiment of the present invention is shown.

[0022] Fig.10 Shows Fig. 9 Right view of .

[0023] Fig.11 A schematic structural diagram of a gear selection and shifting actuator according to a third embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Please refer to Figures 2 to 8 The shift actuator according to the first embodiment of the present invention comprises a shift shaft 1 , a shift sleeve 2 , a guide sleeve 3 , a shift sleeve driving mechanism and a housing 5 .

[0026] The shift sleeve driving mechanism is used to drive the shift sleeve 2 to move axially, and the shift shaft 1 is connected to the shift sleeve 2 to move synchronously with the shift sleeve 2. For example, the shift sleeve 2 can be sleeved on the shift shaft 1, and both ends of the shift sleeve 2 are limited in the axial direction relative to the shift shaft 1, so that the shift shaft 1 can move synchronously with the shift sleeve 2.

[0027] The gear selection sleeve 2 includes a screw 21 and a mounting portion 22. The screw 21 has a first multi-thread unidirectional thread 211, and one end of the screw 21 is connected to the mounting portion 22. The number of threads N of the screw 21 satisfies: the number of threads 5≤N≤7. The lead P of the screw 21 satisfies: 1.5*D1≤P≤2*D1, where D1 is the major diameter of the screw (the major diameter is the maximum outer diameter of the threaded portion on the screw 21). The meaning of unidirectional means that the thread on the screw 21 can only be left-handed or right-handed. In this embodiment, the lead P of the screw is 1.67*D1, and the number of threads N is 6.

[0028] The gear selection sleeve driving mechanism includes a transmission member 41 and a transmission member driving mechanism. The transmission member 41 has a mounting hole 410, and the hole wall of the mounting hole 410 is provided with a second multi-thread unidirectional thread 411 that matches the first multi-thread unidirectional thread 211. The screw 21 passes through the mounting hole 410 and is spirally connected with the transmission member 41. The transmission member driving mechanism is used to drive the transmission member 41 to rotate. In this embodiment, the transmission member 41 is a gear, preferably a bevel gear, and the tooth profile 412 of the bevel gear 41 is arranged on the end face of the bevel gear 41, and the mounting hole 410 is the center hole of the bevel gear 41. The transmission member driving mechanism includes a driving motor 42 and a driving gear 43, and the driving gear 43 is connected to the main shaft 421 of the driving motor 42 to rotate synchronously with the main shaft 421 of the driving motor 42. The driving gear 43 is a bevel gear that matches the bevel gear 41, and the two form a bevel gear pair.

[0029] The guide sleeve 3 is fixedly mounted on the housing 5 of the gear selector actuator, and the freedom of its rotation direction and axial displacement are restricted. The fixed mounting methods include but are not limited to welding, interference fit, etc. The inner wall of the guide sleeve 3 is provided with a first limiting structure and a second limiting structure. The first limiting structure is used to limit the axial movement of the transmission member 41, and the second limiting structure is used to limit the rotation of the gear selector sleeve 2. In this first embodiment, the first limiting structure includes a first groove 31, at least a portion of the bevel gear 41 extends into the first groove 31, and the two end faces of the bevel gear 41 respectively abut against the two side faces of the first groove 31, so that the bevel gear 41 cannot move in the axial direction. The second limiting structure includes a plurality of second grooves 32 extending in a direction parallel to the axis of the screw 21, and the plurality of second grooves 32 are distributed along the circumferential direction. The mounting portion 22 has a plurality of protrusions 222 protruding in the radial direction, the number of the protrusions 222 being the same as the number of the second grooves 32, the plurality of protrusions 222 being distributed at intervals along the circumference of the mounting portion 22, and extending into the plurality of second grooves 32 one by one, wherein the two side surfaces of at least one protrusion 222 respectively abut against the two side walls of the corresponding second groove, thereby limiting the rotation of the gear selector sleeve 2.

[0030] In this embodiment, the top surface 222a of the protrusion 222 is the guide support part, and the side surface 222b of the protrusion 22 is the anti-rotation part. The plurality of second grooves 32 are defined by a plurality of limiting ribs arranged on the inner wall of the guide sleeve. In addition to transmitting motion, the gear selection sleeve 2 also plays the role of radial support, guidance and radial limiting, and is a functional part integrating multiple functions. The advantage of doing so is that it can not only reduce the number of transmission parts in the system, making the structure more compact; but also simplify the product process flow, facilitate assembly and manufacturing; and at the same time reduce costs and facilitate marketization.

[0031] When the driving motor 42 rotates, it drives the bevel gear 41 to rotate. The rotation of the bevel gear 41 drives the gear selection sleeve 2 to move linearly. The linear movement of the gear selection sleeve 2 drives the gear selection shaft 1 to move linearly, thereby completing the gear selection operation.

[0032] The contact surface of the transmission thread when mating is related to the number of thread lines, that is, the more thread lines there are, the greater the contact area is, and under the same torque, the shear strength will be reduced, thus extending the service life of the product. The gear selection sleeve 2 of this embodiment is provided with multiple one-way threads; compared with single-thread threads, it can greatly increase the strength of the parts and reduce the shear strength of the parts, thereby extending the service life of the product.

[0033] The selector sleeve 2 of this embodiment has a large lead (1.5*D1≤P≤2*D1), but the major diameter and minor diameter are more than 1 times smaller than those of the standard thread. The advantage of this is that the volume will not increase accordingly while the transmission ratio of the transmission mechanism is increased, thereby achieving lightweighting of the product.

[0034] The transmission structure of this embodiment is more suitable for the field of large lead and lightweight thread transmission. A large lead means a large transmission ratio, which is advantageous in some application scenarios. In addition, as emission regulations become increasingly stringent, the principle of lightweight has also become an important principle for product design. Therefore, there is an urgent need to provide a transmission structure with both a large lead and a small major diameter. However, when the conventional thread design scheme is adopted, when the lead / major diameter ratio is increased, the degree of thread inclination increases. For the bevel gear 41 of the same thickness, the contact area between the bevel gear 41 and the thread of the gear selection sleeve 2 will be reduced, and the uniformity of the thread distribution on the bevel gear and the gear selection sleeve will be reduced (for example, for the bevel gear of conventional thickness, the thread will be uniformly distributed around the inner circumference of the bevel gear to only distributed on one side of the partial area). This means that under the same torque, the shear strength between the thread and the bevel gear is higher, and the wear of the bevel gear and the gear selection sleeve is more uneven, which further leads to an increase in the eccentricity of the bevel gear, resulting in a greatly reduced service life of the product, abnormal noise, reduced transmission accuracy, and even transmission failure. If the thickness of the bevel gear is increased, the size and weight of the transmission structure will be greatly increased, which does not meet the principle of lightweight. In addition, another problem caused by increasing the lead is that due to the increase in thread pitch, the tooth thickness of the thread on the selector sleeve or bevel gear will be too thick and the tooth groove will be too narrow. During the injection molding process of the product, the material shrinkage will cause serious deformation of the thread after injection molding and large dimensional deviation. In addition, when the number of threads is low, in some areas, the axial distance between the edge of the selector sleeve and the thread will be large, so the thread deformation caused by material shrinkage in this area is more obvious. These all lead to low yield rate, poor precision, great processing difficulty and high cost of the injection molded selector sleeve, and abnormal noise, poor transmission accuracy and even transmission failure will occur during use, greatly reducing the service life of the product.

[0035] In this embodiment, for application scenarios with a large pitch / major diameter ratio, the number of spirals N of the screw is selected to be: 5≤N≤7. By using a higher number of spirals, the thread density on the gear selection sleeve is increased. Without increasing the size of the bevel gear, the contact area between the bevel gear and the thread of the gear selection sleeve is increased, thereby reducing the shear strength of the thread and the bevel gear, and increasing the uniformity of the thread distribution, so that the wear of the bevel gear and the gear selection sleeve is more uniform, avoiding the occurrence of eccentricity of the bevel gear, thereby further extending the service life of the product, avoiding abnormal noise, improving transmission accuracy, and avoiding failure. In addition, when the pitch / major diameter ratio is large, a higher number of spirals is selected, the thread thickness can be reduced, the thread distribution is more balanced, and the distance between the edge of the gear selection sleeve and the thread in the axial direction can also be reduced. During the injection molding process of the product, the deformation of the product after injection molding is smaller due to material shrinkage, thereby further improving the product yield and accuracy, reducing the cost and processing difficulty of the product, and no abnormal noise will occur during the use of the product, and the transmission accuracy is higher.

[0036] In other embodiments, one of the first limiting structure and the second limiting structure may be arranged on the guide sleeve 2, and the other of the first limiting structure and the second limiting structure may be arranged on the housing 5 of the shift selector actuator. In other words, the limiting component of the shift selector actuator is composed of the guide sleeve 3 and the housing 5.

[0037] Fig. 9 and Fig.10 The structure of the shift selector actuator according to the second embodiment of the present invention is shown. The main difference between the second embodiment and the first embodiment is that the guide sleeve 3 is eliminated, and the first groove 31a as the first limiting structure and the second groove 32a as the second limiting structure are both arranged on the housing 5a of the shift selector actuator, that is, the housing 5a serves as the limiting component of the shift selector actuator. Among them, the first groove 31a is defined by the step 51a and the limiting block 52a arranged on the inner wall of the housing 5a to limit the axial position of the bevel gear 41, and the second groove 32a is directly arranged on the inner wall of the housing 5a to limit the rotational freedom of the shift selector sleeve 2.

[0038] Fig.11 The structure of the gear selector and shift actuator according to the third embodiment of the present invention is shown. The main difference between the third embodiment and the first embodiment is that the guide sleeve 3 is eliminated, and the first groove 31b as the first limiting structure and the second groove 32b as the second limiting structure are both arranged on the housing 5b of the gear selector and shift actuator, that is, the housing 5b is used as the limiting component of the gear selector and shift actuator. Among them, the housing 5b is composed of a first housing part 5C and a second housing part 5D, and the first groove 31b is defined by a step 51b arranged at one end of the housing 5C and a limiting block 52b arranged at one end of the housing 5D to limit the axial position of the bevel gear 41, and the second groove 32b is directly arranged on the inner wall of the second housing part 5D to limit the rotational freedom of the gear selector sleeve 2.

Claims

1. A shift actuator, comprising a shift shaft, a shift sleeve and a shift sleeve driving mechanism; the shift sleeve driving mechanism is used to drive the shift sleeve to move axially, the shift shaft is connected to the shift sleeve to move synchronously with the shift sleeve, and is characterized in that: The gear selection sleeve includes a screw having a first multi-thread unidirectional thread; The gear selection sleeve driving mechanism comprises a transmission member and a transmission member driving mechanism; the transmission member has a mounting hole, the hole wall of the mounting hole is provided with a second multi-thread one-way thread matching the first multi-thread one-way thread, the screw rod passes through the mounting hole and is spirally connected with the transmission member; the transmission member driving mechanism is used to drive the transmission member to rotate; The gear selection and shift actuator also includes a limiting component, which is provided with a first limiting structure and a second limiting structure, the first limiting structure is used to limit the axial movement of the transmission member, and the second limiting structure is used to limit the rotation of the gear selection sleeve; the limiting component is a guide sleeve or the housing of the gear selection and shift actuator, and the guide sleeve is fixedly installed on the housing of the gear selection and shift actuator.

2. The gear selection and shifting actuator according to claim 1, characterized in that: The number N of spirals of the screw rod satisfies: 5≤N≤7.

3. The gear selection and shifting actuator according to claim 1 or 2, characterized in that: The lead P of the screw satisfies: 1.5*D1≤P≤2*D1, where D1 is the major diameter of the screw.

4. The gear selection and shift actuator according to claim 1, characterized in that: The gear selection sleeve comprises a mounting portion, and one end of the screw rod is connected to the mounting portion; The second limiting structure cooperates with the mounting portion to limit the rotation of the gear selection sleeve.

5. The gear selection and shift actuator according to claim 1, characterized in that: The first limiting structure includes a first groove, and at least a portion of the transmission member extends into the first groove.

6. The gear selection and shift actuator according to claim 1, characterized in that: The second limiting structure includes a second groove extending in a direction parallel to the axis of the screw; The gear selection sleeve comprises a mounting portion, one end of the screw rod is connected to the mounting portion; the mounting portion has a radially protruding block, and the block extends into the second groove.

7. The gear selection and shift actuator according to claim 6, characterized in that: There are multiple second grooves, and the multiple second grooves are distributed along the circumferential direction; The number of the protrusions is the same as the number of the second grooves. The multiple protrusions are distributed at intervals along the circumference of the mounting portion and extend into the multiple second grooves one by one. The two side surfaces of at least one protrusion respectively abut against the two side walls of the corresponding second groove.

8. The gear selection and shift actuator according to claim 1, characterized in that: The transmission member is a bevel gear, the tooth profile of the bevel gear is arranged on the end surface of the bevel gear, and the mounting hole is the center hole of the bevel gear.

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