Drive system
By adopting tangentially offset dual drive wheel design and motor control in the drive system, the problems of high torque transmission and compensation for tooth irregularity in the shape-fit driving system are solved, and efficient and redundant torque transmission and miniaturization design are achieved.
Patent Information
- Application Number
- CN202510151521.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-02-21
- Filing Date
- 2025-02-11
- Publication Date
- 2025-08-22
AI Technical Summary
When the existing shape-fitting drive systems transmit high torque, they may not be able to achieve proper transmission from the motor to the mating teeth, and the power transmission is limited by the number of meshing teeth of the drive pinion, and cannot effectively compensate for irregularities of the mating teeth such as pitch errors and transition problems, resulting in risk of overload.
At least two drive wheels are adopted, each with meshing elements designed to alternately engage and tangentially offset, compensate for irregularities of mating teeth through motor control and mechanical/hydraulic torque distribution, ensuring uniform meshing of the meshing elements, and redundant transmission is achieved using differential or independent motor drive.
It realizes efficient torque transmission in a smaller space, compensates for the irregularity of the mating teeth, avoids the risk of overload, and has redundant transmission capabilities, with smaller motor size and power.
Smart Images
Figure CN120517445A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a drive system comprising a drive element and a mating toothing (mating gearing), wherein the drive element has at least one drive wheel with a toothing element. Background Art
[0002] Positive-lock drives are used in many areas, such as rack railways in transport systems and in mining operations. Compared to friction drives, positive-lock drives offer significant advantages in terms of increased efficiency, as the drive wheels rarely slip on the drive rails. Furthermore, they can transfer higher torques and the resulting accelerations from the drive to mating teeth (such as racks or toothed chains), thus achieving greater acceleration.
[0003] However, a problem with form-fit drives is that, especially when transmitting high torques, proper transmission from the motor to the mating teeth may not be achieved, and power transmission may be limited by the number of simultaneously engaged teeth on the drive pinion. Furthermore, in some applications, irregularities in the mating teeth, such as pitch errors or transition problems from one mating tooth to the next, may not be satisfactorily compensated.
[0004] This problem could be addressed by increasing the diameter of the drive pinion—that is, by increasing the pitch diameter of the drive pinion that meshes with the mating teeth. However, this significantly increases the space required and results in higher torque requirements, placing greater demands on the gearbox. Furthermore, due to design reasons, even with the increased size of the drive wheel, the individual meshing elements cannot move relative to each other. This means that indexing errors in the mating teeth could result in the entire drive force being transmitted by a single meshing element, at least temporarily, leading to overload of the individual meshing elements.
[0005] A form-fitting drive in the prior art can be found in Patent No. EP2483121B1. Summary of the Invention
[0006] On this basis, the object of the present invention is to provide a drive system which requires less space and can compensate for the pitch error of the mating tooth parts.
[0007] The invention solves this problem by a drive system as claimed in claim 1 , the improved features in the dependent claims relating to preferred embodiments of the invention.
[0008] The drive system of the present invention includes a drive element and mating teeth, wherein the drive element is provided with two or more drive wheels, including a first drive wheel and a second drive wheel, each of which has meshing elements (e.g., teeth). The drive wheels are arranged such that the meshing elements of the first drive wheel and the second drive wheel alternately mesh with the mating teeth, and at least one meshing element of each of the first drive wheel and the second drive wheel remains in meshing engagement with the mating teeth at least temporarily (e.g., when a vehicle equipped with the drive element passes over a particular portion of track with opposing mating teeth) and / or simultaneously.
[0009] The meshing elements of each drive wheel (e.g., the first and second drive wheels) are tangentially offset relative to each other. Tangential offset refers to an offset in the circumferential direction. That is, in radial projection, when the drive system is operating, the meshing elements of the first drive wheel do not overlap with the meshing elements of the second, third, and other drive wheels. Instead, they are offset circumferentially relative to the meshing elements of the other drive wheels. In particular, the drive wheels are designed to have identical configurations, or at least identical radii. Preferably, the meshing elements of the drive wheels are equidistantly spaced along the circumference. For example, in a side (radial) projection of multiple drive wheels arranged one above the other, the meshing elements of the first drive wheel are located between the meshing elements of the other drive wheels. In the case of two drive wheels arranged one above the other, the meshing elements of the first drive wheel are located between the meshing elements of the second drive wheel, and in particular, located centered between the meshing elements of the second drive wheel. However, during operation of the drive system, the tangential offsets of the meshing elements of the individual meshing wheels may vary slightly because the motors used by the drive wheels compensate for irregularities or indexing errors in the mating teeth, particularly by controlling the motor torque.
[0010] Furthermore, the at least two drive wheels can be axially offset and / or coaxially arranged. They can mesh with the same or different portions of the mating toothing. For example, a first drive wheel can mesh with a first mating toothing section, and a second drive wheel can mesh with another mating toothing section (stationary relative to the first mating toothing section).
[0011] If at least two drive wheels share a common electric motor, irregularities or indexing errors can be compensated by mechanical and / or hydraulic torque distribution, in particular by means of a differential.
[0012] This allows at least two independent drive wheels to be arranged one above the other or side by side, parallel and coaxial, and independently controlled. With two drive wheels, each has only half the number of meshing elements; with three drive wheels, it has one-third, and so on. As previously mentioned, the meshing elements of the drive wheels arranged one above the other or side by side are tangentially offset relative to each other, allowing the meshing elements of different drive wheels to engage with mating teeth alternately or sequentially.
[0013] This drive system is a form-fit drive system, in which multiple toothing elements can simultaneously engage with mating teeth. This means that the drive wheel is usually designed as a gear or pinion, which meshes with mating teeth (such as a rack) in a form-fitting manner and transmits torque to the mating teeth.
[0014] The drive system of the present invention has a wide range of applications. For example, when the mating teeth are fixed, a vehicle equipped with a drive wheel can be moved (translated) along the track by transmitting torque from the gears toward the track. The vehicle can be a rail vehicle, such as a transport vehicle or a roller coaster that travels along a track. In other applications, the drive wheel can be fixed, so that the object connected to the mating teeth can be translated. In this case, the drive system acts as a linear drive, similar in design to a screw drive or electric cylinder, capable of applying a large force to the mating teeth / track. Further specialized applications are possible in areas such as machine tools or conveying technology.
[0015] In one embodiment of the present invention, the drive system may have a common motor equipped with at least two drive wheels, and the motor drives the at least two drive wheels by mechanical and / or hydraulic torque distribution.
[0016] Mechanical and / or hydraulic torque distribution includes at least one differential.
[0017] In another embodiment of the present invention, the drive system may be equipped with at least two motors, each driving a drive wheel. The drive wheels operate independently of one another. In radial projection, the position of the second drive wheel's meshing elements is primarily arranged alternately between the meshing elements of the first drive wheel and / or the further drive wheels, or is regularly arranged with a defined tangential offset relative to the meshing elements of the first drive wheel and / or the further drive wheels. However, during operation, the position of the second drive wheel's meshing elements relative to the meshing elements of the first drive wheel and / or the further drive wheels may change, or the position of the second drive wheel's meshing elements relative to the meshing elements of the first drive wheel and / or the further drive wheels may shift during operation.
[0018] If there are more than two driving wheels, a corresponding number of motors can be equipped, and each motor can independently drive a driving wheel.
[0019] In a preferred embodiment of the present invention, the drive system has at least two motors that continuously apply a predetermined (constant) torque at least for a given period of time. For example, torque control can be used to compensate for tooth profile irregularities or clearance issues.
[0020] In a preferred embodiment of the present invention, at least two motors are equipped with torque control or regulation. Torque control / regulation enables precise control of torque output. For example, a controller calculates control instructions based on a comparison of the actual torque with the setpoint, adjusting the motor torque to the setpoint. This is typically achieved by controlling the drive current. The controller can adjust the current amplitude or phase to achieve the desired torque.
[0021] Two or more drive wheels can be electrically controlled to simulate a greater tooth overlap, otherwise achievable only by increasing the pitch diameter. This greater tooth overlap is achieved by controlling the torque of the drive motor, advancing the meshing element until it contacts the mating teeth, thereby applying torque to the contacted teeth of the mating gear. This control method causes the distance between the meshing elements of the first and second drive wheels (and other drive wheels) to vary slightly during operation. This means that the tangential offset of the meshing elements changes and is continuously adjusted to ensure that at least one meshing element on each drive wheel is always engaged with the mating teeth and can transmit a certain ratio of the total drive torque to the mating teeth. The meshing element rotates rapidly until it contacts the teeth of the mating gear and stops. This allows multiple meshing elements to be engaged simultaneously, even with a small pitch diameter.
[0022] The present invention achieves the following objectives:
[0023] The total driving force (torque) generated by the motor can be reliably and evenly distributed on two or more meshing elements (especially the meshing elements of different drive wheels). This means that the size of the meshing elements and the mating teeth can be designed to be smaller.
[0024] The system is redundant. If the first drive train (including the first drive wheel) fails, at least one second drive train (including the second drive wheel) is available, which can continue to provide a certain ratio of total drive force (torque) to maintain operation. The second drive train can be used for emergency operation and motor brake control.
[0025] This system can transmit greater force / torque while requiring less space than a conventional drive system where a single drive wheel transmits power / torque directly to mating teeth.
[0026] Compared with a single high-power drive motor, the motor in the present invention is smaller in size and lower in power.
[0027] At least two drive wheels can be arranged in a radially offset and / or axially offset manner. Typically, the drive wheels are parallel to each other and mesh with the same or different matching tooth portions.
[0028] The driving wheel can be mounted on the vehicle, and the mating gear is fixed to the transport track.
[0029] The mating teeth include at least one rack or chain.
[0030] The engaging elements preferably comprise cylindrical bodies, each having at least one rotatable element adapted to roll on cooperating teeth.
[0031] In particular, the engagement element of at least one of the drive wheels may comprise a member which is movable radially towards the centre of the drive wheel.
[0032] The engaging element can be pushed radially outward from the center of the drive wheel by a resilient force (such as a spring force) so as to precisely engage with the mating teeth. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] More advantages and features of the present invention will become more apparent through the description of the preferred embodiments based on the accompanying drawings. The accompanying drawings are as follows:
[0034] Figure 1 : A perspective view of the drive system of the present invention.
[0035] Figure 2 : Schematic diagram of the arrangement of two drive wheels in the drive system of the present invention.
[0036] Figure 3 : Schematic diagram of another aspect of the present invention. DETAILED DESCRIPTION
[0037] The following examples all relate to the drive system of the present invention.
[0038] Figure 1 A perspective view of a drive system 1 according to the invention is shown, comprising a drive element 2 having two drive wheels 21, 22, and cooperating teeth 3. The drive wheels 21, 22 each have a plurality of meshing elements (e.g. teeth, rotatable rollers), respectively referenced 210a, 210b, 210c... and 220a, 220b, 220c..., Figure 1 Only some of the elements are marked. The meshing elements 210a, 210b, 210c, ...; 220a, 220b, 220c, ... on each driving wheel 21 / 22 are arranged equidistant from each other.
[0039] The mating tooth 3 also has meshing elements 3a, 3b, 3c, Figure 1 Only some components are marked.
[0040] In this embodiment of the present invention, the drive wheels 21 and 22 are coaxially arranged. In this example, the first and second drive wheels 21 and 22 have the same number of meshing elements and the same tooth pitch. The two drive wheels 21 and 22 are aligned tangentially (i.e., circumferentially) so that the meshing elements 210a, 210b, 210c... of the first drive wheel 21 and the meshing elements 220a, 220b, 220c... of the second drive wheel 22 alternately engage with the meshing elements 3a, 3b, 3c... of the mating teeth 3 (relative to the two drive wheels 21 and 22). This is achieved by tangentially (circumferentially) offsetting the n first meshing elements 210a, 210b, 210c..., 210g of the first drive wheel 21 by an angle α relative to the n second meshing elements 220a, 220b, 220c..., 220g of the second drive wheel 22. For example, for two drive wheels 21 and 22, α is approximately 360° / 2N; for three drive wheels, α is approximately 360° / 3N. More generally, α is approximately 360° / (z × N), where z is the number of drive wheels in drive system 1. The value of N can be adjusted based on the number of z, ensuring that the z × N value for a design with z drive wheels roughly corresponds to the N value for a design with a single drive wheel (z = 1).
[0041] Each driving wheel 21 , 22 can be driven independently by its corresponding motor 41 , 42 , or can be driven by one motor transmitting torque through a differential.
[0042] Motors 41 and 42 are electrically controlled to simulate greater tooth overlap for both drive wheels 21 and 22, which typically requires a larger pitch diameter for a single drive wheel. Specifically, the torque of the two drive motors 41 and 42 is controlled so that the teeth of the drive wheels rapidly approach the teeth of the mating teeth until they contact, thereby applying torque. This control method slightly changes the (tangential) distances between the meshing elements 210a and 220a, 210b and 220b, etc. of the two drive wheels 21 and 22. This means that the tangential offset of the drive wheels 21 and 22 changes by an angle Δα (the meshing element offset is α±Δα). This automatically adjusts to ensure that at least one meshing element of each drive wheel 21 and 22 is always engaged with the mating tooth 3, allowing a certain ratio of total drive force / torque to be applied to the mating tooth 3. Rapid forward rotation (until the teeth contact the mating tooth) ensures that, even with a smaller pitch diameter, multiple meshing elements can be simultaneously engaged with the mating tooth 3 within a given timeframe.
[0043] Therefore, the total driving force generated by one or more motors 41 and 42 can be reliably and evenly distributed across two (or more) meshing elements (e.g., 210a, 220a). This means that the meshing elements 210, 220 and the mating teeth 3 can be designed to be smaller. Furthermore, the system provides redundancy: if one drive chain 21, 41 fails, at least the other drive chain 22, 42 can still provide a certain ratio of the total driving force.
[0044] Figure 2 The structure of two parallel and coaxially arranged drive wheels 21 and 22 is shown.
[0045] Starting with a drive wheel 20 having 2n=14 (N=7) meshing elements 200a, 200b...200n, it is split into two drive wheels 21, 22. Each of these two drive wheels 21, 22 has half (N=7) the original 2N=14 meshing elements. Therefore, when these two drive wheels 21 and 22 are arranged transversely and coaxially, the positions of all meshing elements 210a, 210b...210g, 220a, 220b...220g correspond to the positions of the meshing elements 200a, 200b...200n of the original drive wheel 20, and are completely consistent in lateral projection (see FIG. Figure 2 The driving wheel combination 21+22 at the bottom).
[0046] The two coaxially arranged drive wheels 21 and 22 are controlled separately. The toothing elements 210 and 220 of the upper and lower drive wheels 21 and 22 are tangentially offset from each other by approximately 360° / 2n = 360° / 14 ≈ 26°, so that the toothing elements 210a and 220a, 210b and 220b, ..., 210g and 220g of different drive wheels 21 and 22 alternately mesh with the mating teeth 3.
[0047] Figure 3 Another aspect of the present invention is shown, which can be implemented alone or in combination with the above-described embodiments.
[0048] like Figure 3 As shown on the left or as previously described, a conventional drive wheel 21 has meshing elements 210a, 210b, ..., 210h. Conventional drive wheel 21 is a substantially rigid structure. Therefore, the distance between drive wheel 21 and mating teeth 3 must be set relatively precisely, with clearance required to prevent undesirable forces from being applied to the gear head when they come into contact with the mating teeth 3.
[0049] Figure 3The right side shows an improved drive wheel 23. Its meshing elements (e.g., teeth or rollers) 230a, 230b, ..., 230h are radially movable on the drive wheel 23. This reduces the distance between the drive wheel 23 and the mating teeth (e.g., by an amount d) and allows adjustment of the pitch circle of the drive wheel 23. This design saves space. Springs hold the meshing elements in an outboard position to ensure proper meshing. When the drive wheel's meshing elements are at the root of the mating teeth, they are subjected to a reaction force F (e.g., a spring force), compressing them radially. This compensates for any deviations in the distance between the drive wheel 23 and the mating teeth 3.
Claims
1. A drive system (1), comprising: A driving element (2); Matching teeth (3), wherein The drive element (2) has two or more drive wheels (21, 22), including a first drive wheel and a second drive wheel, each drive wheel being provided with an engagement element (210, 220), the engagement element (210) of the first drive wheel (21) being tangentially offset relative to the engagement element (220) of the second drive wheel (22), so that the engagement elements (210, 220) of the drive wheels (21, 22) alternately engage with the mating teeth (3), and at least one engagement element (210) of the first drive wheel (21) and at least one engagement element (220) of the second drive wheel (22) at least temporarily engage with the mating teeth (3).
2. The drive system (1) according to claim 1, comprising a common motor which drives the at least two drive wheels (21, 22) by mechanical and / or hydraulic torque distribution.
3. Drive system (1) according to claim 2, wherein the mechanical and / or hydraulic torque distribution comprises at least one differential.
4. The drive system (1) according to claim 1, comprising at least two motors (41, 42), each of which drives at least one of the drive wheels (21, 22).
5. The drive system (1) according to claim 1, comprising at least two electric motors (41, 42) which are controlled to apply a constant torque at least for a period of time.
6. The drive system (1) according to claim 5, wherein the at least two motors (41, 42) are electric motors with a torque control or torque regulation function.
7. The drive system (1) according to claim 1, wherein the at least two drive wheels (21, 22) are arranged axially offset from each other.
8. The drive system (1) according to claim 1, wherein the at least two drive wheels (21, 22) are coaxially offset from each other.
9. The drive system (1) according to claim 1, wherein the at least two drive wheels (21, 22) are arranged radially offset from each other.
10. The drive system (1) according to claim 1, wherein the drive wheels (21, 22) are mounted on a vehicle and the mating teeth (3) are fixed on a transport track.
11. The drive system (1) according to claim 1, wherein the mating teeth (3) comprise at least one rack.
12. The drive system (1) according to claim 1, wherein the engagement elements (210, 220) are designed as cylinders, each cylinder having at least one rotatable element for rolling on the mating tooth (3).
13. The drive system (1) according to claim 1, wherein the engagement element (230) of at least one of the drive wheels (23) is radially movable relative to the center of the drive wheel (23).
14. The drive system (1) according to claim 13, wherein the engagement element (230) is pushed radially outward from the center of the drive wheel (23) by a spring force (F).