Multi-point meshing transmission mechanism, control method and low-speed rotating table

Abstract

The invention discloses a multi-point meshing transmission mechanism, a control method and a low-speed rotating table. The multi-point meshing transmission mechanism comprises a table gear ring. The two rotating parts are arranged at two different positions in the circumferential direction of the workbench gear ring; each rotating part comprises at least two output gear shafts, and all the output gear shafts are meshed with different positions in the circumferential direction of the workbench gear ring respectively; the two driving parts are connected with the two rotating parts in a one-to-one correspondence mode and used for driving all the output gear shafts in the same rotating part to rotate in the same direction and with the same torque; and the control component is connected with the two driving components and used for cooperatively adjusting the difference value of the two rotating components during torque output and enabling the torque output of the two rotating components to be switched between the same direction and the reverse direction. The multi-point meshing transmission mechanism can eliminate the gear backlash generated by installation and operation of the gear to a great extent, improves the rotation precision and stability, and is suitable for a large rotary table.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gear transmission, in particular to a multi-point meshing transmission mechanism, a control method and a low-speed rotary table. BACKGROUND

[0002] In the field of large vertical rotary machining equipment, the rotary table as a core functional component plays a role in carrying workpieces, indexing and transmitting precision, and requires fast response speed, large load capacity and high rigidity. The table participates in linkage machining, and requires high positioning accuracy and repeat positioning accuracy, fast response and smooth operation, and its performance directly affects the performance of the whole machine.

[0003] Large workpieces have large mass and high inertia, and require large driving torque during machining. The driving of the rotary table needs to consider power transmission and precision transmission. Traditional rotary tables generally use worm gear transmission or single-point meshing gear transmission, and the transmission chain is long and the meshing is single, resulting in high concentration of contact stress. Long-term operation can easily cause problems such as tooth surface wear and fatigue cracks, which seriously affect the service life of the transmission system. At the same time, the centering accuracy of the rotary table decreases exponentially with the increase of size, and with the increasing demand for machining of super-large workpieces, the load capacity of the traditional rotary table is insufficient. SUMMARY

[0004] The purpose of the present application is to provide a multi-point meshing transmission mechanism, a control method and a low-speed rotary table. The multi-point meshing transmission mechanism can greatly eliminate the backlash of the gear caused by installation and wear, improve the rotary accuracy and stability, and is suitable for large rotary tables.

[0005] The technical scheme adopted by the present application is: a multi-point meshing transmission mechanism, comprising a table gear ring; two rotating parts are arranged at two different positions in the circumferential direction of the table gear ring; each rotating part comprises at least two output gear shafts, and all the output gear shafts are meshed at different positions in the circumferential direction of the table gear ring; two driving parts are connected to the two rotating parts one by one, for driving all the output gear shafts in the same rotating part to rotate in the same direction and with the same torque; a control part is connected to the two driving parts respectively, for cooperatively adjusting the difference between the two rotating parts when outputting torque, and switching the torque output of the two rotating parts between the same direction and the opposite direction.

[0006] As a preferred scheme, each driving part comprises a servo motor and two gear pairs, the input ends of the two gear pairs are connected to the output end of the servo motor, and the output ends of the two gear pairs are connected to the two output gear shafts respectively.

[0007] As a preferred scheme, the gear pair is a reduction gear pair.

[0008] As a preferred solution, the control component is a controller, and the controller is electrically connected with the two servo motors respectively.

[0009] As a preferred solution, the two rotating components are centrally symmetric about the axis of the worktable gear ring.

[0010] A control method of a multi-point meshing transmission mechanism, the two rotating components are a first rotating component and a second rotating component respectively, and the control method comprises: Starting of the worktable gear ring: control the directions of the torque outputs of the two rotating components to be opposite and the magnitudes to be T1, T1>0; Keeping the directions of the torque outputs of the two rotating components unchanged, control the torque output of the first rotating component to gradually increase to T2, and control the torque output of the second rotating component to gradually decrease to zero; Adjusting the directions and magnitudes of the torque outputs of the second rotating component, so that the directions of the torque outputs of the two rotating components are the same and the magnitudes are both T2; Stopping of the worktable gear ring: keeping the directions of the torque outputs of the two rotating components unchanged, control the torque outputs of the two rotating components to decrease simultaneously, wherein the torque output of the first rotating component is reduced to T1 and then stopped after being reduced from T2; After the torque output of the second rotating component is reduced to zero, adjusting the directions and magnitudes of the torque outputs of the second rotating component, so that the directions of the torque outputs of the two rotating components are opposite and the magnitudes are both T1.

[0011] As a preferred solution, the rotating direction of the worktable gear ring is the reverse direction of the output gear shaft in the first rotating component.

[0012] A low-speed rotary worktable, comprising a worktable base, a worktable and a multi-point meshing transmission mechanism, the worktable base is rotationally connected with the worktable, and the worktable gear ring of the multi-point meshing transmission mechanism is fixed on the worktable.

[0013] As a preferred solution, a conical hydrostatic bearing is arranged on the worktable base, and a radial load oil film is enclosed between the conical hydrostatic bearing and the worktable.

[0014] As a preferred solution, a slide plate is arranged on the worktable base, and an axial load oil film is enclosed between the slide plate and the worktable.

[0015] Compared with the prior art, the present application has the following beneficial effects: 1. The multi-point meshing transmission mechanism of the present application, the multiple output gear shafts of the same rotating part and all the multiple output gear shafts of different rotating parts can compensate each other during transmission, the transmission is more stable, the acceleration performance is good, the reverse transmission gap can be reduced, and the working precision of the rotary table is further improved; all the output gear shafts are simultaneously meshed with the gear teeth of the table gear ring, and the rotary table is driven by the gear teeth, and a large torque can be transmitted.

[0016] 2. The control method of the multi-point meshing transmission mechanism of the present application, the torque generated by the servo motor is transmitted to the table gear ring through the output gear shaft and drives the rotary table, the output torque of the two servo motors is reasonably distributed to make the rotary table stationary, forward and reverse, eliminate the backlash, improve the transmission precision of the rotary table, and reduce the machining precision requirement of the transmission gear.

[0017] 3. The low-speed rotary table of the present application adopts the multi-point meshing transmission mechanism to drive the table, the overall operation is stable and the rotary precision is high, and the design and machining difficulty of the large rotary equipment is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is a three-dimensional structure schematic diagram of the low-speed rotary table of the present application; Figure 2 is a sectional structure schematic diagram of the low-speed rotary table of the present application; Figure 3 is a three-dimensional structure schematic diagram of the low-speed rotary table of the present application; Figure 4 is a sectional structure schematic diagram of the low-speed rotary table of the present application; Figure 5 is Figure 2 is a local enlarged schematic diagram of A in FIG. Figure 6 is Figure 5 is a local schematic diagram of the conical hydrostatic bearing in Y direction in FIG. Figure 7 is the overall control block diagram of the present application.

[0020] Illustration markings: 100, workbench base; 101, base; 102, inner sliding plate; 103, outer sliding plate; 104, conical hydrostatic support; 1041, hydrostatic chamber; 105, mating plate; 200, workbench; 201, workbench body; 202, workbench gear ring; 300, multi-point meshing transmission mechanism; 301, servo motor; 302, locking disc; 303, transmission housing; 304, input gear shaft; 305, second-stage gear shaft; 306, third-stage gear shaft; 307, output gear shaft; 308, first-stage gear; 309, second-stage gear; 310, third-stage gear. Detailed Implementation

[0021] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0023] To more clearly describe the multi-point meshing transmission mechanism, control method, and specific composition of the low-speed rotary table, see attached... Figures 1-7 This embodiment is described as follows: like Figures 1-4 As shown, a multi-point meshing transmission mechanism 300 includes a rotating component, a driving component, and a control component; There is one 202 gear ring on the worktable; The rotating components are arranged in pairs and are located at two different positions in the circumferential direction of the table gear ring 202; each rotating component includes at least two output gear shafts 307, and all the output gear shafts 307 are respectively meshed at different positions in the circumferential direction of the table gear ring 202. There are two drive components, which are connected to the two rotating components one by one, and are used to drive all the output gear shafts 307 in the same rotating component to rotate in the same direction and with the same torque. The control component is connected with the two driving components respectively, and is used for cooperatively adjusting the difference of the two rotating components in torque output, and switching the torque output of the two rotating components between the same direction and the opposite direction, wherein the torque output of the rotating component still refers to the torque output of each output gear shaft 307.

[0024] In the above embodiment, all the output gear shafts 307 in the same rotating component rotate in the same direction and with the same torque. Due to the existence of the tooth side gap and the machining error, the tooth of one output gear shaft 307 is engaged with the tooth of the workbench gear ring 202 first, and the tooth of the other output gear shaft 307 is engaged with the tooth of the workbench gear ring 202 later. During the rotating process, the teeth of the two output gear shafts 307 compensate each other. The same is true for the reverse rotation. After the tooth side gap is small, the tooth of the output gear shaft 307 is engaged with the tooth of the workbench gear ring 202 first. After the gear is worn, the two output gear shafts 307 can also compensate each other. Through the parallel transmission of the double gears, the tooth side gap is reduced, the gear precision requirement is reduced, and at the same time, larger torque can be transmitted, and the transmission is more stable.

[0025] Similarly, the torque output of the output gear shaft 307 between the two rotating components can be switched between the same direction and the opposite direction, and the difference of the torque output of the output gear shaft 307 between the different rotating components can be adjusted by the control component. The tooth side gap is reduced by the torque difference and the direction change between the two rotating components.

[0026] In a feasible scheme, two rotating components are provided, each rotating component includes two output gear shafts 307, and the four output gear shafts 307 are simultaneously engaged with the teeth of the workbench gear ring 202 to drive the workbench 200 together, which can transmit larger torque, the transmission is more stable, and the carrying capacity of the workbench is improved.

[0027] In a feasible scheme, each driving component includes a servo motor 301 and two gear pairs. The input ends of the two gear pairs are connected with the output end of the servo motor 301, and the output ends of the two gear pairs are connected with the two output gear shafts 307 respectively. That is, the two output gear shafts 307 are driven to rotate by the servo motor 301, so as to ensure that the directions of the output torques of the two output gear shafts 307 in the same rotating component are the same, and the sizes are equal.

[0028] In order to ensure the driving characteristics of large torque and heavy load, the gear pair is a reduction gear pair.

[0029] Referring to Figure 3 and Figure 4In a specific embodiment, each gear pair comprises an input gear shaft 304, a second-stage gear shaft 305, a third-stage gear shaft 306, an output gear shaft 307, a first-stage gear 308, a second-stage gear 309, a third-stage gear 310 mounted in the transmission box 303. The servo motor 301 drives the input gear shaft 304 to rotate under the connection of the locking disc 302. The input gear shaft 304 is in gear engagement with the first-stage gear 308. The first-stage gear 308 is connected with the second-stage gear shaft 305. The second-stage gear shaft 305 is in gear engagement with the second-stage gear 309. The second-stage gear 309 is connected with the third-stage gear shaft 306. The third-stage gear shaft 306 is in gear engagement with the third-stage gear 310. The third-stage gear 310 is connected with the output gear shaft 307. The output gear shaft 307 is in gear engagement with the worktable gear ring 202. The servo motor 301 drives the two output gear shafts 307 through three-stage gear transmission, and the two output gear shafts 307 jointly drive the worktable gear ring 202. When the servo motor 301 rotates clockwise, the input gear shaft 304 rotates counterclockwise, the second-stage gear shaft 305 rotates clockwise, the third-stage gear shaft 306 rotates counterclockwise, the output gear shaft 307 rotates clockwise, and the worktable gear ring 202 rotates counterclockwise. The two output gear shafts 307 rotate in the same direction and drive the worktable gear ring 202 to rotate in parallel. The rotation direction of the worktable gear ring 202 is consistent with that of the servo motor 301.

[0030] Specifically, the control component is a controller, and the controller is electrically connected with the two servo motors 301 respectively.

[0031] Referring to Figure 1 In a feasible technical solution, the two rotating components are centrally symmetric about the axis of the worktable gear ring 202. This design can ensure that the worktable gear ring 202 is uniformly stressed when the multi-point gear transmission is used.

[0032] Referring to Figure 7 A control method of a multi-point meshing transmission mechanism, the two rotating components are a first rotating component and a second rotating component, and the control method comprises: Starting of the worktable gear ring 202: a. The directions of the torque outputs of the two rotating components are opposite, and the magnitudes are T1, T1>0. This step can eliminate the gap between the output gear shaft 307 and the worktable gear ring 202, so that the position can be kept unchanged in the static state and the vibration offset force generated by the main shaft can be resisted, and the workpiece can be kept stable during machining; b. The directions of the torque outputs of the two rotating components are kept unchanged, the torque output of the first rotating component is gradually increased to T2, and the torque output of the second rotating component is gradually reduced to zero. This step can reduce the re-release of the backlash during the speed-up process. c. Adjusting the direction and size of the second rotating component torque output, so that the directions of the torque outputs of the two rotating components are the same and the sizes are both T2; Stopping of the worktable gear ring 202: d. Keeping the directions of the torque outputs of the two rotating components unchanged, and controlling the torque outputs of the two rotating components to be reduced simultaneously, wherein the torque output of the first rotating component is reduced from T2 to T1 and then stopped; e. After the torque output of the second rotating component is reduced to zero, adjusting the direction and size of the second rotating component torque output, so that the directions of the torque outputs of the two rotating components are opposite and the sizes are both T1.

[0033] Steps d and e are also used to eliminate the backlash in the deceleration process.

[0034] The above control method has the characteristics of multi-point meshing and simultaneous driving of double servo motors, provides reverse torque when the worktable gear ring 202 is stationary and rotating, ensures that the transmission is rigidly connected and has no backlash, and can also provide an adjustable damping to overcome the non-linear link generated by large inertia, and achieve precise positioning and indexing under system control instructions.

[0035] In the control method, the direction of rotation of the output gear shaft 307 in the first rotating component does not need to be adjusted, so the direction of rotation of the worktable gear ring 202 is the reverse of the output gear shaft 307 in the first rotating component, that is, the direction of rotation of the worktable gear ring 202 can be determined and adjusted according to the rotation direction of the servo motor corresponding to the first rotating component and the number of gears in the gear pair.

[0036] Referring to Figures 1-6 A low-speed rotary worktable includes a worktable base 100, a worktable 200, and a multi-point meshing transmission mechanism. The worktable base 100 is rotationally connected with the worktable 200. The worktable 200 includes a worktable body 201. The worktable gear ring 202 of the multi-point meshing transmission mechanism is fixed on the worktable body 201.

[0037] The worktable base 100 mainly includes a base 101, an inner slide plate 102, an outer slide plate 103, and a conical hydrostatic bearing 104 on the base 101.

[0038] Referring to Figure 2 and Figure 5 The conical hydrostatic bearing 104 has an annular structure. The inner annular surface is a cylindrical surface, and the outer annular surface is a conical surface with a specific angle. A plating layer is arranged on the outer conical surface of the conical hydrostatic bearing 104 to form a plurality of annular radial pressure accumulation grooves, i.e., hydrostatic cavities 1041, which are used to bear the radial load oil film between the conical hydrostatic bearing 104 and the worktable 200. Furthermore, the inner conical surface of the worktable 200 is parallel to the outer conical surface of the conical hydrostatic support 104. The upper surface of the conical hydrostatic support 104 is provided with oil holes connected to the hydrostatic chambers. The oil holes are connected to an external constant oil flow pump to supply oil to each hydrostatic chamber at a constant flow rate, ensuring that the oil pressure is not lower than a certain pressure. Within the allowable pressure range, a load oil film is formed between the conical hydrostatic support 104 and the worktable 200, which can simultaneously withstand axial load, radial load and overturning moment. It has good centering accuracy, low dynamic and static friction coefficient, low starting power, high precision, high oil film stiffness, and excellent low-speed performance, and can achieve ultra-low speed operation.

[0039] In one specific installation method, the lower end face of the tapered hydrostatic support 104 contacts the upper surface of the mating plate 105, the lower surface of the mating plate 105 contacts the upper surface of the base 101, and the tapered hydrostatic support 104 is connected to the base 101 by screws.

[0040] See Figure 2 The lower surface of the worktable 200 contacts the upper surfaces of the inner slide plate 102 and the outer slide plate 103. The contact surface between the lower surface of the worktable 200 and the base 101 is an inner and outer annular surface composed of multiple fan-shaped surfaces. By filling the oil hole of the base 101 with appropriate oil, the friction of the rotation of the worktable is reduced. The oil hole is used to bear the axial load oil film between the slide plate and the worktable 200. In one specific embodiment, both the inner slide plate 102 and the outer slide plate 103 are fan-shaped structures with annular grooves on their upper surfaces and are connected to the base 101 by screws. The upper surfaces of both the inner and outer slide plates 102 are provided with oil cavities and through holes connected to the oil holes on the base. The inner slide plates 102 are evenly distributed on the circumference with a smaller diameter, and the outer slide plates 102 are evenly distributed on the circumference with a larger diameter. The lower surface of the worktable 200 contacts the upper surfaces of the inner slide plates 102 and the outer slide plates 103. The contact surface between the lower surface of the worktable 200 and the base 101 is an inner and outer annular surface composed of multiple fan-shaped surfaces. By filling the oil holes of the base 101 with appropriate oil, the friction of the rotating worktable is reduced.

[0041] The parts not described in detail in the above embodiments are existing technologies.

[0042] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A multi-point meshing transmission mechanism, characterized in that, include: Table gear ring (202); Two rotating components are disposed at two different positions in the circumferential direction of the table gear ring (202); each rotating component includes at least two output gear shafts (307), and all output gear shafts (307) are respectively meshed at different positions in the circumferential direction of the table gear ring (202); Two drive components are connected one-to-one with two rotating components to drive all output gear shafts (307) in the same rotating component to rotate in the same direction and with the same torque; The control unit is connected to two drive units respectively, and is used to coordinately adjust the difference in torque output between the two rotating units, and to switch the torque output of the two rotating units between the same direction and opposite directions.

2. The multi-point meshing transmission mechanism according to claim 1, characterized in that: Each drive component includes a servo motor (301) and two gear pairs. The input ends of the two gear pairs are connected to the output ends of the servo motor (301), and the output ends of the two gear pairs are respectively connected to two output gear shafts (307).

3. The multi-point meshing transmission mechanism according to claim 2, characterized in that: The gear pair is a reduction gear pair.

4. A multi-point meshing transmission mechanism according to claim 2, characterized in that: The control component is a controller, which is electrically connected to two servo motors (301).

5. A multi-point meshing transmission mechanism according to claim 1, characterized in that: The two rotating components are symmetrical about the axis of the table gear ring (202).

6. A control method for a multi-point meshing transmission mechanism as described in claim 1, characterized in that, The two rotating components are a first rotating component and a second rotating component, and the control method includes: Start-up of the table gear ring (202): The control makes the torque output of the two rotating parts opposite in direction and both of magnitude T1, T1>0; Keeping the direction of the torque output of the two rotating components unchanged, the torque output of the first rotating component is gradually increased to T2, while the torque output of the second rotating component is gradually decreased to zero. Adjust the direction and magnitude of the torque output of the second rotating component so that the torque output of the two rotating components is in the same direction and the magnitude is T2. Stopping the table gear ring (202): Keep the direction of the torque output of the two rotating parts unchanged, and control the torque output of the two rotating parts to decrease simultaneously, wherein the torque output of the first rotating part stops after decreasing from T2 to T1; After the torque output of the second rotating component is reduced to zero, the direction and magnitude of the torque output of the second rotating component are adjusted so that the directions of the torque outputs of the two rotating components are opposite and the magnitudes are both T1.

7. The control method according to claim 6, characterized in that: The rotation direction of the table gear ring (202) is the opposite of that of the output gear shaft (307) in the first rotating component.

8. A low-speed rotary table, characterized in that: It includes a worktable base (100), a worktable (200), and a multi-point meshing transmission mechanism as described in any one of claims 1-5, wherein the worktable base (100) is rotatably connected to the worktable (200), and the worktable gear ring (202) of the multi-point meshing transmission mechanism is fixed on the worktable (200).

9. A low-speed rotary table according to claim 8, characterized in that: A conical hydrostatic support (104) is provided on the worktable base (100), and a radial load oil film is sealed between the conical hydrostatic support (104) and the worktable (200).

10. A low-speed rotary table according to claim 8, characterized in that: A slide plate is provided on the worktable base (100), and an axial load oil film is sealed between the slide plate and the worktable (200).

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