CN108626315B - A point-line meshing worm lifting mechanism - Google Patents

Abstract

The invention relates to the technical field of mechanical transmission, in particular to a dotted line meshing worm lifting mechanism. The tooth shapes of the worm and the worm wheel and the gear in the invention have involute and circular arcs, namely, half of the tooth height of the gear teeth is an involute convex tooth profile, the other half is a concave tooth profile of a transition curve, and when the worm and the worm wheel are in operation, different tooth profile curves are meshed to present different meshing effects. When the transition curve tooth profile is meshed with the involute tooth profile, the transition curve tooth profile is in point contact; when the involute profile meshes with the involute profile, the involute profile exhibits line contact. The invention is characterized in that: 1) The dotted line meshing of the gears is promoted to the dotted line meshing of the worm and the worm wheel, so that a theoretical system of the dotted line meshing of the gears is further enriched, and the application range of worm transmission is widened. 2) The worm is meshed with the dotted line of the bevel gear, so that the processing difficulty is reduced, and the connotation and the extension of worm transmission are expanded. 3) The dotted line meshed worm gear has the double advantages of an involute worm gear and an arc worm gear, and the strength is higher.

Description

A point-line meshing worm lifting mechanism

Technical Field

The invention relates to the technical field of mechanical transmission, and in particular to a point-line meshing worm lifting mechanism.

Background Art

Worm gear transmission is widely used due to its advantages of large transmission ratio, stable transmission, small vibration and low noise. The performance and quality of worm gear transmission will ultimately affect the quality of machine products.

The failure forms of worm gear transmission are often manifested as tooth pitting, bonding, tooth wear and gear tooth breakage, etc. Due to material and structural reasons, the strength of the worm helical tooth part is always higher than the strength of the worm wheel teeth, so failure often occurs on the worm wheel teeth.

Summary of the invention

In order to solve the problem in the prior art that the gear teeth of the worm wheel or helical gear are prone to failure when the worm wheel or helical gear is matched with the worm, the present invention provides a point-line meshing worm lifting mechanism that can improve the bending strength of the tooth root of the worm wheel or helical gear.

The technical solution adopted by the present invention to solve the technical problem is:

A point-line meshing worm lifting mechanism, comprising a first helical gear and a second helical gear meshing with each other, a first connecting shaft fixed to the center of the second helical gear, a first bevel gear fixed to the other end of the first connecting shaft, a second bevel gear meshed with the first bevel gear, a second connecting shaft fixed to the second bevel gear, a worm fixed to the other end of the second connecting shaft, a transmission wheel meshed with the worm, the transmission wheel is a worm wheel or a third helical gear, a third connecting shaft fixed to the transmission wheel, a fourth helical gear fixed to the third connecting shaft, a fifth helical gear meshed with the fourth helical gear, a roller fixed to the end surface of the fifth helical gear, and the rotation axis of the roller and the fifth helical gear coincide, a traction rope for lifting or lowering a heavy object is wound around the roller, and the lifting mechanism needs to meet the following conditions:

1) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix angle of the first helical gear and the second helical gear are z ₁ , z ₂ , m _n1 , m _{n2 ,} m _{t1 , m t2} , α _n1 , α _n2 , α _t1 , α _t2 , β ₁ , β ₂ , respectively. The values of z ₁ and z ₂ can be determined as needed while no undercutting is required. β ₁ and β ₂ are usually 8° to 20° and satisfy β ₁ ＝β ₂ . m _n1 , m _n2 , α _n1 , α _n2 can be determined as needed or taken from the gear manual, but must satisfy: m _n1 cos α _t1 /cos β ₁ ＝m _n2 cos _{α t2} /cos β ₂ , α _t1 ＝arctg(tgα _n1 /cosβ ₁ ), α _t2 = arctg (tgα _n2 /cosβ ₂ );

2) The number of teeth, large end module and large end pressure angle of the first bevel gear and the second bevel gear are z ₃ , z ₄ , m ₃ , m ₄ , α ₃ and α ₄ respectively, wherein the values of z ₃ and z ₄ can be determined as required while ensuring no undercutting; m ₃ , m ₄ , α ₃ and α ₄ can be determined as required or taken from the gear manual, but must satisfy m ₃ cosα ₃ =m ₄ cosα ₄ ;

3) The number of heads, diameter coefficient, axial module and axial pressure angle of the worm are z ₅ , q ₅ , m _x5 , α _x5 , respectively, where z ₅ is usually 1, 2, 4, 6; the value of q ₅ can be referred to the gear design manual; m _x5 and α _x5 can be determined according to needs or taken from the gear manual, but the specific values are related to the end module and end pressure angle of the transmission wheel (6); the pitch circle lead angle of the worm is γ ₅ = arctanz ₅ /q ₅ degrees;

4) The number of teeth, pitch circle helix angle, end face module and end face pressure angle of the transmission wheel are z ₆ , β ₆ , m _t6 , and α _t6 respectively. When the transmission wheel is a worm gear, the value of z ₆ is usually between 28 and 80; when the transmission wheel is a third helical gear, the value of z ₆ can be determined according to the needs without root cutting; β ₆ can be determined according to the needs; m _t6 and α _t6 can be determined according to the needs or taken from the gear manual, but must meet the following conditions: m _x5 cosα _x5 = m _t6 cosα _t6 , and α _x5 <α _t6 . When the angle between the worm and the transmission wheel is 90 degrees, β ₆ = γ ₅ is also satisfied;

5) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix angle of the fourth helical gear and the fifth helical _{gear are z7, z8, mn7, mn8, mt7, mt8, αn7, αn8, αt7, αt8, β7 , β8 respectively , wherein the values of z7 and z8 can be} determined as needed under the condition of no undercutting; _β7 and _β8 are usually 8°~20°, and _β7 ＝ _-β8 ; _mn7 , _mn8 , _{αn7, αn8 can} be determined as needed or taken from the gear manual, but must satisfy the following: _{mn7 cosαt7} / _cosβ7 ＝ _{mn8 cosαt8} / _cosβ8 , _αt7 ＝arctg( _tgαn7 / _cosβ7 ), α _t8 =arctg(tgα _n8 /cosβ ₈ ).

Furthermore, the first helical gear and the second helical gear are internally meshed.

Furthermore, the tooth profiles of the first helical gear, the second helical gear, the first bevel gear, the second bevel gear, the worm, the transmission wheel, the fourth helical gear and the fifth helical gear teeth are half convex tooth profiles with involute tooth profiles and the other half concave tooth profiles with transition curve tooth profiles.

Beneficial effects:

1) The point-line meshing of gears is extended to the point-line meshing of worms and worm wheels, which further enriches the theoretical system of point-line meshing of gears and broadens the application scope of worm transmission; 2) The point-line meshing of worms and helical gears reduces the difficulty of processing and expands the connotation and extension of worm transmission; 3) The point-line meshing worm wheel has the dual advantages of involute worm wheels and circular arc worm wheels, and has higher strength. Therefore, compared with conventional worm transmission mechanisms, the present invention has the advantages of large load-bearing capacity, long service life, high reliability, no easy tooth breakage, and convenient processing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

FIG1 is a schematic structural diagram of a point-line meshing worm lifting mechanism of the present invention;

FIG. 2 shows the point-line meshing form of the point-line meshing worm lifting mechanism of the present invention.

Among them, 1. the first bevel gear, 2. the second bevel gear, 3. the first circular bevel gear, 4. the second circular bevel gear, 5. the worm, 6. the transmission wheel, 7. the fourth bevel gear, 8. the fifth bevel gear, 9. the roller, and 10. the weight.

DETAILED DESCRIPTION

As shown in Figure 1, a point-line meshing worm lifting mechanism comprises a first bevel gear 1 and a second bevel gear 2 meshing with each other, a first connecting shaft is fixed at the center of the second bevel gear 2, a first bevel gear 3 is fixed at the other end of the first connecting shaft, a second bevel gear 4 is meshed on the first bevel gear 3, a second connecting shaft is fixed on the second bevel gear 4, a worm 5 is fixed at the other end of the second connecting shaft, a transmission wheel 6 is meshed on the worm 5, the transmission wheel 6 is a worm wheel or a third bevel gear, a third connecting shaft is fixed on the transmission wheel 6, a fourth bevel gear 7 is fixed on the third connecting shaft, a fifth bevel gear 8 is meshed on the fourth bevel gear 7, a drum 9 is fixed on the end surface of the fifth bevel gear 8, and the rotation axis of the drum 9 and the fifth bevel gear 8 coincide, a traction rope for lifting or lowering a heavy object 10 is wound around the drum 9, and the lifting mechanism needs to meet the following conditions:

1) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix angle of the first helical gear 1 and the second helical gear 2 are z ₁ , z ₂ , m _n1 , m _n2 , m _t1 , m _t2 , α _n1 , α _n2 , α _t1 , α _t2 , β ₁ , β ₂ , respectively. The values of z ₁ and z ₂ can be determined as required under the condition of no undercutting; β ₁ and β ₂ are usually 8° to 20° and satisfy β ₁ ＝β ₂ ; m _n1 , m _n2 , α _n1 , α _n2 can be determined as required or taken from the gear manual, but must satisfy: m _n1 cos α _t1 /cos β ₁ ＝m _n2 cos α _t2 /cos β ₂ , α _t1 ＝arctg(tgα _n1 /cosβ ₁ ), α _t2 = arctg (tgα _n2 /cosβ ₂ );

2) The number of teeth, large end module and large end pressure angle of the first bevel gear 3 and the second bevel gear 4 are z ₃ , z ₄ , m ₃ , m ₄ , α ₃ and α ₄ respectively, wherein the values of z ₃ and z ₄ can be determined as required while ensuring no undercutting; m ₃ , m ₄ , α ₃ and α ₄ can be determined as required or taken from the gear manual, but must satisfy m ₃ cosα ₃ =m ₄ cosα ₄ ;

3) The number of heads, diameter coefficient, axial module and axial pressure angle of the worm 5 are z ₅ , q ₅ , m _x5 , and α _x5 , respectively, where z ₅ is usually 1, 2, 4, or 6; the value of q ₅ can be referred to the gear design manual; m _x5 and α _x5 can be determined according to needs or taken from the gear manual, but the specific values are related to the end module and end pressure angle of the transmission wheel 6; the pitch circle lead angle γ ₅ of the worm 5 is arctanz ₅ /q ₅ degrees;

4) The number of teeth, pitch circle helix angle, end face module and end face pressure angle of the transmission wheel 6 are z ₆ , β ₆ , m _t6 , and α _t6 respectively. When the transmission wheel 6 is a worm gear, the value of z ₆ is usually between 28 and 80; when the transmission wheel 6 is a third helical gear, the value of z ₆ can be determined according to the needs without root cutting; β ₆ can be determined according to the needs; m _t6 and α _t6 can be determined according to the needs or taken from the gear manual, but must meet the following conditions: m _x5 cosα _x5 =m _t6 cosα _t6 , and α _x5 <α _t6 . When the angle between the worm 5 and the transmission wheel 6 is 90 degrees, β ₆ =γ ₅ is also satisfied;

5) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix _{angle of the fourth helical gear 7 and the fifth helical gear 8 are z7, z8, mn7, mn8, mt7, mt8, αn7, αn8, αt7, αt8, β7 , β8 respectively , wherein the values of z7 and z8 can be} determined as needed under the condition of no undercutting; _β7 and _β8 are usually 8°~20°, and _β7 ＝ _-β8 ; _mn7 , _mn8 , _αn7 , _αn8 can be determined as needed or taken from the gear manual, but must satisfy _{the following} : _{mn7 cosαt7} /cosβ7＝ _{mn8 cosαt8} /cosβ8, _αt7 ＝arctg( _tgαn7 /cosβ ₇ ), α _t8 =arctg(tgα _n8 /cosβ ₈ ).

In the present invention, the first helical gear 1 and the second helical gear 2 are internally meshed.

The tooth profiles of the first helical gear 1, the second helical gear 2, the first bevel gear 3, the second bevel gear 4, the worm 5, the transmission wheel 6, the fourth helical gear 7 and the fifth helical gear 8 have both involute and arc, that is, half of the tooth height of the gear is an involute convex tooth profile, and the other half is a transition curve concave tooth profile. When working, different tooth profile curves will mesh with each other to present different meshing effects. When the transition curve tooth profile meshes with the involute tooth profile, it is a point contact; when the involute tooth profile meshes with the involute tooth profile, it is a line contact. As shown in Figure 2, the two meshing gears are defined as gear 1 and gear 2. In the figure, at the point P where the pitch circles of the two gears are tangent, O ₁ O ₂ is the center line, N ₁ N ₂ is the meshing line segment, and J is the meshing point.

It should be understood that the specific embodiments described above are only used to explain the present invention, and are not used to limit the present invention. Obvious changes or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims (1)

1. A point-line meshing worm lifting mechanism, characterized in that it comprises a first bevel gear (1) and a second bevel gear (2) meshing with each other, a first connecting shaft being fixed at the center of the second bevel gear (2), a first bevel gear (3) being fixed at the other end of the first connecting shaft, a second bevel gear (4) being meshed on the first bevel gear (3), a second connecting shaft being fixed on the second bevel gear (4), a worm (5) being fixed at the other end of the second connecting shaft, a transmission wheel (6) being meshed on the worm (5), the transmission wheel (6) being a worm wheel or a third bevel gear, a third connecting shaft being fixed on the transmission wheel (6), a fourth bevel gear (7) being fixed on the third connecting shaft, a fifth bevel gear (8) being meshed on the fourth bevel gear (7), a roller (9) being fixed on the end surface of the fifth bevel gear (8), and the rotation axis of the roller (9) and the fifth bevel gear (8) being coincident, a traction rope for lifting or lowering a weight (10) being wound around the roller (9), and the lifting mechanism needs to meet the following conditions: 1) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix angle of the first helical gear (1) and the second helical gear (2) are respectively:

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Usually 1, 2, 4, 6 are selected;

The value of can be found in the gear design manual;

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The value can be set by yourself or taken from the gear manual according to the needs, but the specific value is related to the end face module and end face pressure angle of the transmission wheel (6); the pitch circle lead angle of the worm (5)

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The value range of is usually between 28 and 80; when the transmission wheel (6) is the third helical gear,

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Can be customized according to needs;

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You can define it as needed or take the value from the gear manual, but it must meet the following requirements:

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; 6) The number of teeth, normal module, end module, normal pressure angle, end pressure angle and pitch circle helix angle of the fourth helical gear (7) and the fifth helical gear (8) are respectively

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The value can be set as required while satisfying the requirement of no undercutting;

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You can define it as needed or take the value from the gear manual, but it must meet the following requirements:

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; The first helical gear (1) and the second helical gear (2) are internally meshed; The tooth profiles of the first helical gear (1), the second helical gear (2), the first bevel gear (3), the second bevel gear (4), the worm (5), the transmission wheel (6), the fourth helical gear (7) and the fifth helical gear (8) include both involute and circular arc, that is, half of the tooth height of the gear teeth is a convex tooth profile of an involute tooth profile, and the other half is a concave tooth profile of a transition curve tooth profile.

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