Backlash-eliminating gear transmission mechanism

Abstract

The backlash-eliminating gear transmission mechanism comprises a first transmission shaft and a second transmission shaft, the first transmission shaft is provided with a first gear, the second transmission shaft is provided with a second gear and a third gear which are meshed with the first gear, the second gear is fastened to the second transmission shaft, and the third gear is fastened to the second transmission shaft. The third gear is rotatably arranged relative to the second transmission shaft and tightly attached to the second gear, a movable part capable of changing the position in the axial direction of the second gear is arranged on the second gear, an inclined face is arranged on the third gear, and the movable part makes contact with the inclined face. And when the position of the movable part is changed, the third gear is pushed to rotate through the inclined surface, so that the teeth of the second gear and the teeth of the third gear are respectively in contact with two tooth surfaces, in different directions, of the teeth of the first gear. The gear backlash of gear transmission can be eliminated, rigid pre-tightening is achieved, and clamping stagnation caused by uneven gear backlash is avoided.

Description

Technical Field

[0001] The invention relates to a gear transmission device, belonging to the technical field of transmission component clearance adjustment. Background Art

[0002] During the gear transmission process, due to the existence of gear side clearance, the transmission mechanism has lost motion when reversing, which makes the mechanism unable to accurately position, seriously reducing the transmission accuracy. At the same time, due to the existence of side clearance, transmission noise is generated when the mechanism is running, affecting the servo control accuracy.

[0003] The prior art often uses the double-piece gear spring staggered tooth method to eliminate the gear transmission side clearance. Two thin gears are assembled together, one of which is fixed on the shaft, and each gear has two circumferential through grooves. The two thin gears are respectively equipped with lugs, one end of the tension spring is hooked on the lug, and the other end is hooked on the fixing screw. The nut is used to adjust the extension length of the screw and lock it. During assembly, the spring has sufficient tension so that the left and right sides of the two thin gears are respectively close to the left and right sides of the wide gear to eliminate the tooth side clearance.

[0004] This mechanism relies on the elastic force of the spring to press the movable thin gear against the other side of the wide gear to eliminate the side clearance. When the transmission mechanism reverses, the transmission gear applies torque to the movable thin gear, and the movable thin gear drives the fixed thin gear through the elastic tension of the spring, thereby transmitting the motion to the output shaft. It can be seen that in order to achieve gapless gear transmission during reversal, the elastic torque generated by the elastic force of the spring must be greater than the transmission torque of the gear in the reverse direction. Otherwise, the spring will be stretched, resulting in a gap. Excessive elastic force of the spring will produce excessive clamping force on the gear teeth, aggravating the friction and wear of the gear and reducing the service life of the gear.

[0005] The prior art also provides mutually matching wedge-shaped surfaces on the two thin gears to control the relative position of the two thin gears to eliminate the tooth side clearance. However, due to inconsistent pre-tightening force of the screws connecting the two thin gears or clearance between the gear shafts, the thin gears will be non-parallel and tilted, causing the gear clearance to change, the gears to wear, or even to get stuck and damage when the two thin gears are running. Summary of the invention

[0006] In view of the defects of the above-mentioned prior art, the present invention provides a backlash eliminating gear transmission mechanism, which aims to eliminate the backlash of the gear transmission and solve the problems that the elastic force is limited in size when eliminating the backlash and the wedge surface is used to adjust the backlash, which easily causes the gear to tilt and get stuck.

[0007] The technical solution of the present invention is as follows: A backlash eliminating gear transmission mechanism comprises a first transmission shaft and a second transmission shaft, the first transmission shaft is provided with a first gear, the second transmission shaft is provided with a second gear and a third gear meshing with the first gear, the second gear is fastened to the second transmission shaft, the third gear is rotatably arranged relative to the second transmission shaft and is in close contact with the second gear, the second gear is provided with a movable part which can change its position along the axial direction of the second gear, the third gear is provided with an inclined surface, the movable part is in contact with the inclined surface, and when the position of the movable part changes, the third gear is pushed to rotate through the inclined surface so that the teeth of the second gear and the teeth of the third gear respectively contact the two tooth surfaces in different directions of the teeth of the first gear.

[0008] Furthermore, the third gear is provided with a through slot, the movable member is arranged through the through slot, and the inclined surface is arranged on a side wall of the through slot.

[0009] Furthermore, a plurality of movable members are evenly arranged along the circumferential direction on the second gear, and a plurality of inclined surfaces on the third gear are provided corresponding to the movable members.

[0010] Furthermore, the number of the movable parts is three to six.

[0011] Furthermore, the movable member is a cone head screw, the movable member is threadedly connected to the second gear, and the cone surface of the cone head screw is in contact with the inclined surface.

[0012] Furthermore, the second gear is provided with an axially protruding hub, and the third gear is rotatably sleeved on the axially protruding hub.

[0013] Furthermore, a retaining spring is provided on the axial protruding section, and the retaining spring limits the axial movement of the third gear.

[0014] Compared with the prior art, the advantages of the technical solution provided by the present invention are:

[0015] The present invention sets the third gear in close contact with the second gear, and uses the movement of the movable part to push the third gear to rotate only, so that the second gear and the third gear will not tilt, there is no problem of uneven gear gap, wear is small, and there is no jamming. The movable part is used to push the third gear to rotate, so that the rigid pre-tightening between the two gears can be achieved, and the cone head screw is used as the movable part, so that the second gear and the third gear are a kind of rigid pre-tightening with adjustable pre-tightening force, which has the advantages of easy processing, easy adjustment, high precision, no side clearance, low wear, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the backlash eliminating gear transmission mechanism of the embodiment.

[0017] Figure 2 It is a schematic cross-sectional structural diagram of the second gear and the third gear of the backlash eliminating gear transmission mechanism of the embodiment.

[0018] Figure 3 A schematic diagram of the structure of the third gear of the backlash elimination gear transmission mechanism of the embodiment

[0019] Figure 4 It is a partial cutaway schematic diagram of the backlash eliminating gear transmission mechanism of the embodiment.

[0020] Figure 5 It is a front view of the backlash eliminating gear transmission mechanism of the embodiment.

[0021] Figure 6 for Figure 5 A partial enlarged view of point A in the middle. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading this description, various equivalent modifications to this description by those skilled in the art fall within the scope defined by the claims attached to this application.

[0023] Please combine Figures 1 to 3 As shown, the backlash elimination gear transmission mechanism of this embodiment includes a first transmission shaft, a second transmission shaft, a first gear 5, a second gear 1 and a third gear 2. The first transmission shaft and the second transmission shaft are not shown in the figure. The first transmission shaft and the second transmission shaft can be various shafts in the prior art, and can be installed with the first gear 5, the second gear 1 and the third gear 2. The first gear 5 is installed on the first transmission shaft, and the second gear 1 and the third gear 2 are installed on the second transmission shaft.

[0024] Specifically, the first gear 5 is a wide gear (relative to the second gear 1 and the third gear 2), which is fastened to the first transmission shaft, and the second gear 1 is a thin gear (relative to the first gear 5), which is fastened to the second transmission shaft. An axially protruding hub 13 is provided at the center of the second gear 1, and the axially protruding hub 13 is coaxial with the second transmission shaft. The third gear 2 is also a thin gear (relative to the first gear 5), which is sleeved on the axially protruding hub and tightly attached to the second gear 1, so that the third gear 2 can rotate on the axially protruding hub 13, and then the third gear 2 can also rotate relative to the second transmission shaft. An elastic retaining spring 4 is used on the axially protruding hub 13 of the second gear 1 to limit the axial movement of the third gear 2.

[0025] Three to six movable parts are evenly arranged on the second gear 1 along the circumferential direction, and these movable parts can move axially along the second gear 1. In this embodiment, four threaded holes 12 are evenly processed on the second gear 1 along the circumferential direction, and the axial direction of the threaded holes 12 is parallel to the axial direction of the second gear 1. Four cone head screws 3 are installed on the second gear 1 as movable parts through the threaded holes 12. By turning the cone head screws 3, the axial position of the cone head screws 3 and the second gear 1 can be changed, and then the position of the third gear 2 can be adjusted. The use of cone head screws 3 makes the transmission mechanism simple in structure and easy to adjust, and it is also convenient to fix the position of the movable parts after adjustment.

[0026] The third gear 2 is provided with an inclined surface 23, so that when the cone head screw 3 on the second gear 1 changes its axial position after rotation, the inclined surface 23 can push the third gear 2 to rotate a certain angle, so that the teeth of the second gear 1 and the teeth of the third gear 2 are respectively in contact with two tooth surfaces of the teeth of the first gear 5 in different directions. In this embodiment, four through grooves 22 are evenly opened along the circumferential direction on the third gear 2, and the number of through grooves 22 matches the number of cone head screws 3, and the positions correspond. The width of the through groove 22 is slightly larger than the head diameter of the cone head screw 3. A inclined surface 23 is designed at one end of the through groove 22, and the inclination angle of the inclined surface 23 is consistent with the angle of the conical surface 31 of the head of the cone head screw 3, so that the conical surface 31 of the cone head screw 3 fits with the inclined surface 23.

[0027] During installation, firstly put the third gear 2 on the second gear 1, insert the elastic retaining ring 4 to limit the axial movement of the third gear 2, then align the through slot 22 of the third gear 2 with the threaded hole 12 of the second gear 1, and screw the cone head screw 3 through the through slot 22 into the threaded hole 12 for installation.

[0028] The adjustment process of the device for eliminating backlash of the invention is as follows: Figures 4 to 6 As shown. The conical surface 31 of the cone head screw 3 presses against the inclined surface 23 of the through groove 22 on the third gear 2. When the cone head screw 3 is tightened, the cone head screw 3 moves axially along the second gear 1, and the conical surface 31 of its head also moves axially, so that the inclined surface 23 pressing against the conical surface 31 produces circumferential movement, and finally the third gear 2 rotates relative to the second gear 1 and keeps the third gear 2 and the second gear 1 in close contact. Figure 5 and Figure 6 As shown, when the cone head screw 3 is tightened, the third gear 2 moves counterclockwise. The lower side of the tooth 51 on the first gear 5 contacts the upper side of the tooth 11 on the second gear 1, and the upper side of the tooth 51 on the first gear 5 contacts the lower side of the tooth 21 on the third gear 2. As the cone head screw 3 is tightened, the third gear 2 rotates counterclockwise relative to the second gear 1, thereby clamping both sides of the tooth 51 on the first gear 5, eliminating the gear side clearance, and maintaining the preload force.

[0029] The four (or more) cone head screws 3 should be evenly applied with pre-tightening force in multiple times, and the final pre-tightening torque should be equal. The backlash-eliminating pre-tightening force applied by the cone head screws 3 is an adjustable rigid pre-tightening force.

[0030] During the final assembly and adjustment, thread glue may be applied to the threads of the cone head screw 3 to prevent loosening and vibration.

[0031] As the transmission mechanism runs for a long time, the gears will be slightly worn and produce side clearance. It only needs to re-tighten the cone head screw 3, and the transmission mechanism can realize the side clearance elimination transmission again, which is easy to adjust.

Claims

1. A backlash elimination gear transmission mechanism, comprising a first transmission shaft and a second transmission shaft, wherein the first transmission shaft is provided with a first gear, and the second transmission shaft is provided with a second gear and a third gear meshing with the first gear, wherein: The second gear is fastened to the second transmission shaft, the third gear is rotatably arranged relative to the second transmission shaft and is tightly attached to the second gear, the second gear is provided with a movable part which can change its position along the axial direction of the second gear, the third gear is provided with an inclined surface, and the movable part contacts the inclined surface. When the position of the movable part changes, the inclined surface pushes the third gear to rotate so that the teeth of the second gear and the teeth of the third gear respectively contact two tooth surfaces in different directions of the teeth of the first gear.

2. The backlash-eliminating gear transmission mechanism according to claim 1, characterized in that: The third gear is provided with a through slot, the movable member is arranged through the through slot, and the inclined surface is arranged on a side wall of the through slot.

3. The backlash-eliminating gear transmission mechanism according to claim 1, characterized in that: A plurality of movable members are evenly arranged along the circumferential direction on the second gear, and a plurality of inclined surfaces on the third gear are provided corresponding to the movable members.

4. The backlash-eliminating gear transmission mechanism according to claim 3, characterized in that: There are three to six movable parts.

5. The backlash-eliminating gear transmission mechanism according to claim 1 or 2, characterized in that: The movable part is a cone head screw, the movable part is threadedly connected to the second gear, and the cone surface of the cone head screw is in contact with the inclined surface.

6. The backlash-eliminating gear transmission mechanism according to claim 1, characterized in that: The second gear is provided with an axially protruding hub, and the third gear is rotatably sleeved on the axially protruding hub.

7. The backlash-eliminating gear transmission mechanism according to claim 6, characterized in that: A retaining spring is provided on the axial protruding section, and the retaining spring limits the axial movement of the third gear.

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