JPH0560204A - Stepped intermediate gear - Google Patents

Abstract

PURPOSE:To cancel nearly all the sum of thrust forces occurring in a helical stepped intermediate gear and thereby reduce the torque loss by having a specific relation in number of teeth, module and helix angle between a gear on the driving side and a gear on the driven side and having the same direction of the two helix angles. CONSTITUTION:In order to make nearly equal the thrust force of a gear 1 on the driving side and the thrust force of a gear 2 on the driven side, it is necessary to have the relation It where Z1, Z2, m1, m2 and beta1, beta2 are the number of teeth, a module and a helix angle, respectively of a gear 1 and a gear 2 on the driving and the driven side, and it is necessary to have the same direction of the two helix angles. Then, assuming that there is no torque loss due to friction in tooth surface and in bearing portion, the thrust force acting in the gear 1 and in the gear 2 are equal, so that the overall thrust force acting in the whole gear becomes zero, thereby nullifying the torque loss due to friction in the thrust direction. In actuality, in a stepped intermediate gear, there is thrust load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical gear, and in particular, has a fixed coaxial two stepped helical gears to cancel the thrust force of the two gears. The present invention relates to a stepped intermediate gear and a stepped intermediate gear (hereinafter, simply referred to as a stepped intermediate gear) that is fixed to a rotating shaft that is rotatably and movably in an axial direction and bears a thrust force at a gear boss portion. is there.

[0002]

2. Description of the Related Art Conventionally, stepped intermediate gears of helical gears have been widely used in various fields. Since the thrust force acts on the helical gear, it causes problems such as torque loss due to frictional force generated between the bearing and the end surface of the gear boss. Therefore, in the case of the stepped intermediate gear of the helical gear, the helical directions of the teeth are set in the same direction, and the thrust force of the drive side gear that receives the drive force from the preceding stage gear and the drive force from the drive side gear are received. It is known to reverse the thrust force of the coaxial gear on the driven side to reduce the thrust force acting on the entire stepped intermediate gear.

[0003]

However, in the above-mentioned conventional example, although it is conceived that the helical directions of the helical gears of the stepped intermediate gear are the same, the gears of the front and rear stages meshing with the stepped intermediate gear are not considered. It is usually assumed that the relationship with the gear specifications is assumed, and it is not necessary to determine the stepped intermediate gear by taking into consideration the helical gear twist angle so that the thrust force is balanced. Not not.

From the point of view of gear manufacturing, for example, the twist angle may be 15 °, and when a gear cutting machine whose twist angle is not necessarily limited is used, two large and small stepped intermediate gears have the same twist angle. For example, it is often set at 15 °. Therefore, the thrust force generated in the stepped intermediate gear is not sufficiently offset. Therefore, the thrust force applied between the boss portion of the stepped intermediate gear and the bearing causes friction loss and torque loss, and wear of the bearing and the boss portion causes wear to impair durability.

According to the present invention, in a stepped intermediate gear fixed to a rotating shaft rotatably supported by a fixed shaft or rotatably supported so as to be movable in the axial direction, a thrust force acting on the stepped intermediate gear is almost completely offset. It is intended to provide an attached intermediate gear.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a driving-side gear that coaxially meshes with a power-source-side gear and a driven-side gear that receives a driving force from the driving-side gear and meshes with a load-side gear. In the stepped intermediate gear of the helical shaft supported movably in the axial direction, the number of teeth of the drive side gear, the module, and the helix angle are respectively z ₁ , m ₁ , β ₁ , and the number of teeth of the driven side gear. ,
If the module and twist angle are z ₂ , m ₂ and β ₂ , respectively, In addition, the stepped intermediate gear is characterized in that the twisting directions of the tooth lines are the same.

The number of teeth of the drive side gear of the helical stepped intermediate gear,
Module, helix angle, pitch radius, cutting line load, thrust force z ₁ , m ₁ , β ₁ , r ₁ , T _t1 , F _{x1 respectively}
, Number of teeth of driven side gear, module, helix angle, pitch radius, cutting line load, thrust force, respectively z ₂ , m
₂ , β ₂ , r ₂ , F _t2 , and F _x2 , the torque T generated on the driving side and the driven side of the stepped intermediate gear is T = F _t1 r ₁ = F _t2 r ₂ Further, F _x1 = F _t1 tanβ ₁ F _x2 = F _t2 tanβ _{2 In} order to cancel the thrust force of the gear on the driving side and the driven side, the twisting directions of the teeth should be the same direction, and F _x1 = F _x2 F _t1 tanβ ₁ = F _t2 tan β ₂ ········· (2) Equation (1) ÷ (2) That is, in order to cancel the thrust force of the helical stepped intermediate gear, the directions of the torsion angles should be the same, Should be satisfied.

In reality, since there is a torque loss due to friction on the tooth surface and the shaft, F _t1 r ₁ ≤ F _t2 r ₂ . In addition, the magnitude of the torque on the drive side including the torque loss is calculated by the size of the module, the diameter of the shaft, the value of the friction coefficient, the relationship between the meshing positions of the drive side and the driven side, etc. Since it depends on the size, roughly, F _t1 r ₁ ≈ F _t2 r ₂ Even so, it can contribute to a considerable reduction in torque loss. At this time, the thrust force F _x acting on the entire helical stepped intermediate gear is F _x = | F _x1 −F _x2 | = | F _t1 tanβ ₁ −F _t2 tanβ ₂ | ≧ 0, The magnitude of F _x naturally varies depending on the magnitude of the torque of the load, but if it is a little magnitude, the thrust load acts on the entire stepped intermediate gear without significantly increasing the torque loss. Generally, a stepped intermediate gear that is rotatably provided on a fixed shaft or a stepped intermediate gear that is fixed on a rotating shaft that is axially movably supported, is designed to smoothly rotate in the thrust direction. , There is a gap between the gear boss and the thrust bearing surface so that it can move a little. If the thrust force acting on the gear is zero, the position of the gear in the thrust direction will not be determined. In the case of a helical gear, the present inventor has previously proposed that the effect of reducing the torque fluctuation of the motor that is the power source is reduced by setting the overlapping meshing ratio to an integer. When the position of the gear in the thrust direction changes, the meshing tooth width changes, and as a result, the overlapping meshing ratio changes, causing torque fluctuations. In addition, considering the strength and deflection of the gear, it is not preferable that the meshing tooth width varies. According to the present invention, since a slight thrust force acts on the entire gear, the position of the gear in the thrust direction is determined and the meshing tooth width is stabilized.

[0009]

【Example】

[Example 1] In the stepped intermediate gear of the helical gear, the number of teeth, the module, and the helix angle of the drive-side gear are respectively z
₁ , m ₁ and β ₁ , the number of teeth of the gear on the driven side, the module, and the twist angle are z ₂ , m ₂ , and β ₂ , respectively, so that the thrust forces of the driving-side gear and the driven-side gear are almost equal. Is And the directions of the twist angles should be the same.
For example, z ₁ = 17, m ₁ = 0.6, z ₂ = 34, m ₂ = 0.4
given that, For example, when β ₁ = 15 °, β ₂ = 20.187 ° may be set.

FIG. 1 is a diagram showing a stepped intermediate gear of this helical type. The gear 1 on the driven side that meshes with a gear (not shown) on the load side is z ₁ = 17, m ₁ = 0.6, β. ₁ = 15 °. The gear 2 on the driving side that meshes with a gear (not shown) on the power source side and transmits the driving force to the gear 1 on the driven side is z ₂ = 34, m _2.
= 0.4 and β ₂ = 20.187 °. In this case, the direction of the twist angle is right for both gear 1 and gear 2, but gear 1 and gear 2
Both may be on the left. In this way, assuming that there is no torque loss due to friction on the tooth flanks or bearings, the thrust forces acting on the gear 1 and gear 2 are equal, so the total thrust force acting on the entire gear is 0. Therefore, torque loss due to friction in the thrust direction can be eliminated.

In reality, since there is a torque loss due to friction on the tooth surface and the bearing portion, a thrust load acts on this stepped intermediate gear.

For example, assuming that the cutting line load F _t1 acting on the gear 1 is 1 kgf, assuming that there is no torque loss, the cutting line load F _t2 acting on the gear 2 is Therefore, F _t2 = 0.73 kgf, but in reality, there is a torque loss. For example, if F _t2 = 0.8 kgf, then F _x1 = F _t1 tan β ₁ = 268 gf F _x2 = F _t2 tan β ₂ = 294 gf Is. That is, for the entire stepped intermediate gear, F _x = | F _x1 −
A thrust force of F _x2 | = 26 gf acts, and as a result,
The position of the stepped intermediate gear is determined in the thrust direction.

If β ₁ = β ₂ = 20.187 ° and there is no torque loss, Therefore, F _t2 = 0.75 kgf F _x1 = F _t1 tan β ₁ = 368 gf F _x2 = F _t2 tan β ₂ = 276 gf. That is, the entire _{gear, F x = | F x1 -F} x2 | =
A thrust force of 92 gf acts. (Actually, there is a torque loss.) The numerical values of the specifications of the gears shown in the present embodiment are merely examples, and it goes without saying that the present invention is not limited to these.

FIG. 2 shows an embodiment of a gear train having the aforementioned stepped intermediate gear. The gear 2 meshes with a gear 3 that is integral with a motor shaft of a motor M that is a power source, the gear 1 meshes with an idle gear 4, the idle gear 4 is an idle gear 5, and the idle gear 5 is a rotating body T that produces a load. It meshes with an integral gear 6. Such a gear train has less torque loss and can reduce the maximum allowable torque of a power source such as a motor.
It contributes to low power consumption and miniaturization of the entire device. Also,
The load does not matter.

[0015]

As described above, in the stepped intermediate gear of the helical gear, the number of teeth of the gear on the driving side, the module, and the twist angle are respectively z ₁ , m ₁ β ₁ , and the teeth of the gear on the driven side. The number, module, and twist angle are z ₂ , m ₂ , and β, respectively.
_{If 2} By making the directions of the torsion angles the same, the total sum of thrust forces generated in the stepped intermediate gear of the helical can be almost completely offset, and the torque loss can be reduced. Further, in reality, since there is torque loss due to friction on the tooth surface and the bearing portion, a slight thrust direction force acts on the entire stepped intermediate gear, and the thrust direction position is determined.
As a result, the meshing tooth width can be stabilized.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a flow sheet of one embodiment of a drive transmission device.

[Explanation of symbols]

 1 Drive side gear that meshes with the load side gear 2 Driven side gear that meshes with the power source side gear

Claims (1)

[Claims] 1. A drive-side gear that meshes with a power-source-side gear and a driven-side gear that receives a driving force from the drive-side gear and meshes with a load-side gear are axially movable coaxially. In the supported stepped intermediate helical gear, the number of teeth, the module and the helix angle of the drive side gear are respectively z ₁ , m
₁ , β ₁ , the number of teeth of the gear on the driven side, the module, and the twist angle are z ₂ , m ₂ , and β ₂ , respectively, The stepped intermediate gear is characterized in that the helical directions of the teeth are the same.