JP2001065666A - Gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the rotation torque strength between a gear and a wheel gear fixed thereto, to reduce dimension of the wheel gear, and to lower the cost while restricting the quantity of the resin material in the gear having the resin wheel gear integrally fixed to a metal rotary shaft thereof. SOLUTION: One end of a rotary shaft 14 of a gear is provided with a gear fixing part 20. The gear fixing part 20 has a projecting part 22 formed with plural projections 24 in the peripheral surface thereof and a flange part 26. These projecting part 22 and the flange part 26 are formed by the cold forging while being plastically deformed, and a boss part of a wheel gear is integrally fixed to the periphery of the gear fixing part 20. Since depth of the projections 24 can freely be set independently of the number of projections and the length of the circumference, rotation torque strength between the rotary shaft 14 and the wheel gear can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gear gear used for a worm reduction mechanism or the like.

[0002]

2. Description of the Related Art For example, a worm speed reduction mechanism is applied to a drive source (wiper motor) of a vehicle wiper device.
As a gear gear (worm gear) used in the worm reduction mechanism, a gear gear in which a wheel gear made of a resin material is integrally formed and fixed to one end of a metal rotating shaft is known (for example, Japanese Utility Model Application Laid-Open No. JP-139723, JP-A-57-143870).

In this type of gear gear, as shown in FIG. 15, a parallel knurl 62 (or serration) is applied to a rotating shaft 60, and a wheel gear is integrally formed with a resin material on the parallel knurl 62 and fixed. Have been.

In such a gear gear, the parallel knurls 62 (or serrations) provided on the rotating shaft 60 have a saw-like shape as shown in FIG. 16, and the depth of the knurls depends on the circumferential length and the number of strips. Limited by Therefore, when the rotational torque between the rotating shaft 60 and the wheel gear is large, the rotational torque strength is increased by increasing the axial length of the parallel knurls 62 and the serrations.

However, in such a conventional gear gear, the fixed portion (boss portion) of the wheel gear is integrally formed of a resin material around the parallel knurls 62 and the serration portion of the rotating shaft 60, so that the rotating gear is formed. If the length of the parallel knurls 62 and the serrations in the axial direction is increased in order to increase the torque strength, the boss portion of the wheel gear is inevitably elongated in the axial direction, and an extra resin material is required. Furthermore, since it is a composite part in which a wheel gear made of a resin material is fixed to a metal rotating shaft 60 by integral molding, when the resin material is cooled and hardened, the heat conduction of the rotating shaft 60 portion is good, so that the cooling and hardening is performed. The heat shrinkage causes so-called sink marks and warpage on the wheel gears. The “sink” and “slipping” of the wheel gear become more remarkable as the resin volume of the boss around the rotating shaft 60 increases, and as described above, if the boss is long, the wheel gear is deformed as a whole, and the gear teeth become worm gears. There have been problems such as the inability to mesh, the backlash to increase, and the generation of noise during gear driving.

[0006]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a gear gear in which a wheel gear made of a resin material is fixed to a metal rotary shaft by integral molding. A gear gear capable of sufficiently increasing the rotational torque strength between the gear and the wheel gear, reducing the amount of resin material for forming the wheel gear, reducing costs, and preventing the occurrence of problems due to deformation of the wheel gear. The goal is to obtain

[0007]

According to a first aspect of the present invention, there is provided a gear gear in which a wheel gear made of a resin material is fixed to a metal rotary shaft by integral molding. A plurality of ridges that are plastically deformed by cold forging to press the mold from the direction and are formed on the outer peripheral surface along a plurality of ridges, and adjacent to the ridge or the ridge. A gear fixing portion having a retaining portion formed along a circumferential direction, wherein the wheel gear has a disk-shaped gear portion having gear teeth formed on a peripheral edge thereof; and A boss portion fixed to the gear fixing portion by integral molding,
It is characterized by:

In the gear gear according to the present invention, a boss portion of a wheel gear made of a resin material is fixed to a gear fixing portion of a metal rotary shaft by integral molding.

Here, the gear fixing portion of the rotating shaft forms a plurality of ridges along the axial direction by plastically deforming the rotating shaft by cold forging. While improving the material strength itself,
No waste material such as cutting powder is generated, and the depth (height) of the protrusion can be set without being limited by the number of protrusions or the circumferential length. Therefore, the rotational torque strength of the wheel gear with respect to the fixed rotating shaft can be increased. Further, the axial length of the ridge can be reduced by the improvement of the rotational torque strength.

As a result, a small volume of resin is required in the boss portion of the wheel gear around the rotation shaft (around the gear fixing portion), so that the deformation of the wheel gear due to so-called "sink" or "slipping" after thermosetting is small.

Further, with respect to the axial pull-out strength of the rotary shaft with respect to the wheel gear, a retaining portion is formed along the circumferential direction adjacent to the ridge or the ridge.
The resin material of the boss portion of the wheel gear filled in the gear fixing portion is fixed to the rotating shaft while being hooked on the retaining portion in the axial direction. Therefore, if this retaining portion is formed by the same cold forging as the formation of the ridge portion, sufficient strength can be obtained with the same processing apparatus even in the axial removal.

According to a second aspect of the present invention, in the gear gear according to the first aspect, each of the ridges of the ridge portion has a substantially rectangular cross section orthogonal to the axial direction of the rotation shaft. It is characterized by being done.

[0013] Here, in the conventional ridges of serrations and parallel knurls, the rotational torque between the rotating shaft and the wheel gear is received on a slope having a serrated peak, so that the rotational torque strength is reduced. The adhesive strength between the side surface and the contact surface of the resin material partially depends on the adhesive strength, and a sufficiently large rotational torque intensity cannot be obtained.

On the other hand, in the gear gear according to the second aspect, since the cross-sectional shape of each ridge of the ridge is formed to be substantially rectangular, the rotation of the wheel gear with respect to the rotating shaft in the ridge portion. A surface contact state substantially perpendicular to the direction (a state received on the side surface of the ridge) is obtained. That is, unlike the conventional case, since it is not received on a slope having a saw-like mountain, the rotational torque strength of the wheel gear with respect to the rotating shaft can be increased.

According to a third aspect of the present invention, in the gear gear according to the first or second aspect, the retaining portion of the rotating shaft is further provided at an end of the ridge portion on the mold pressing side. It is characterized in that it is a flange formed by ironing by extrusion.

In the gear gear according to the third aspect, a flange as a retaining portion is formed at the end of the ridge on the die pressing side by the same cold forging as the formation of the ridge. The resin material of the boss portion of the wheel gear filled in the gear fixing portion is fixed to the rotating shaft while being hooked on the flange portion in the axial direction. Therefore, sufficient strength can be obtained with the same processing apparatus also with respect to the removal strength of the rotating shaft with respect to the wheel gear in the axial direction, that is, the removal of the ridge portion in the mold pressing side direction.

Since the end of the ridge portion on the side opposite to the die pressing side is originally formed by the formation of the ridge, the resin material of the boss portion of the wheel gear is fixed in such a manner as to be hooked here. The removal strength in the axial direction (in the direction opposite to the mold pressing side) can be secured.

[0018]

FIG. 1 is a perspective view schematically showing a wiper motor 40 for a wiper device, to which a gear gear 10 according to an embodiment of the present invention is applied. I have. FIG. 2 is a cross-sectional view showing the configuration of the gear 10.

The wiper motor 40 has a structure in which a motor section 40A and a gear section 40B are provided integrally. An armature (not shown) is accommodated in the motor section 40A, and a worm gear 42 is provided at the end. The worm gear 42 is inserted into the housing 44 of the gear portion 40B, and
Of the wheel gear 12.

A gear gear 10 is arranged in the gear section 40B of the wiper motor 40. The gear 10 is
The wheel gear 12 made of a resin material has a metal rotating shaft 14.
The gear portion 4
The wheel gear 12 is accommodated in a housing 44 of the OB, and the rotating shaft 14 protrudes from the housing 44 to the outside. The above-described worm gear 42 is meshed with the wheel gear 12 of the gear gear 10, so that the motor gear 40A drives the wheel gear 12 and the rotating shaft 14 of the gear gear 10 to rotate integrally. .

Here, as shown in detail in FIG. 3, the rotating shaft 14 of the gear gear 10 is formed with a tapered flat knurl portion 16 and a screw portion 18 at one axial end (tip), which are not shown. A crank arm for driving the wiper device is connected and fixed.

A gear fixing portion 20 is provided at the other axial end (base end) of the rotating shaft 14 of the gear 10. The gear fixing portion 20 is formed by a plurality of ridges 2 that are plastically deformed by cold forging that presses a mold from the axial direction and are formed along the axial direction.
4 is formed on the outer peripheral surface;
Has a flange portion 26 and a stepped portion 28 as retaining portions formed by ironing by further extrusion at the end of the mold pressing side. The ridge portion 22 is formed to have a smaller diameter than the main body portion of the rotating shaft 14, and each ridge portion 24 is formed to have a substantially rectangular cross section orthogonal to the axial direction as shown in FIG.

On the other hand, the wheel gear 12 has a disk-shaped gear portion 30 having gear teeth 32 formed on a peripheral edge thereof,
And a boss portion 34 for fixing the O. 0 to the gear fixing portion 20 of the rotating shaft 14 by integral molding. This wheel gear 12
Is fixed to the gear fixing portion 20 of the rotating shaft 14 by integral molding.

Next, the operation of the present embodiment will be described together with the procedure for manufacturing the gear 10.

The gear gear 10 having the above-described structure is configured such that a wheel gear 12 made of a resin material is integrally fixed to a rotating shaft 14 made of metal.

Here, the rotating shaft 14 of the gear 10
The ridge 22 and the flange 26 are formed by cold forging. That is, as shown in FIG. 5A, first, the column material X is cut into a predetermined length. Next, as shown in FIG. 5B, the front end of the material is formed in a tapered shape by cold forging (front extrusion) (tapered portion Y). Further, as shown in FIG. 5C, the tapered portion Y is similarly formed into a stepped shape by cold forging (extrusion forward) (stepped portion Z).

Further, as shown in FIG. 5 (D), a flat tapered knurled portion 16 is formed in the tapered portion Y by cold forging (extrusion forward).

Next, as shown in FIG. 5 (E), a plurality of ridges 24 (forged grooves) extending in the axial direction are formed at the rear end of the material by cold forging (rear extrusion). As a result, the ridge 22 is formed. Further, FIG.
As shown in (F), a flange 26 and a stepped portion 28 are formed at the end of the ridge 22 on the mold pressing side by ironing by further extrusion. Thereby, the ridge 22 and the flange 26
Is formed.

Further, as shown in FIG. 5 (G), a threaded portion 18 is formed by rolling at a stepped portion Z on the tip side of the tapered flat knurled portion 16 to complete the rotating shaft 14 itself.

Further, the boss portion 34 of the wheel gear 12 is fixed to the gear fixing portion 20 by molding integrally with the rotating shaft 14 thus processed, whereby the gear gear 10 is completed. That is, the gear gear 10 is a metal rotating shaft 1.
4, the wheel gear 1 made of a resin material
The two boss portions 34 are fixed by integral molding.

Here, Table 1 shows that the gear gear 10 according to the present embodiment and a parallel knurl are formed on the rotary shaft by cutting and rolling, and a wheel gear is formed of a resin material around the parallel knurl. The data of the conventional gear gears formed integrally with each other are shown in comparison.

[0032]

[Table 1]

In the gear gear 10 according to the present embodiment, the flow of material is caused to flow to the gear fixing portion 20 of the rotary shaft 14 by plastically deforming the groove portion between the ridges 24 by cold forging. Since the plurality of ridges 24 are formed along the axial direction by generating the material, the material strength itself can be improved by work hardening by forging, and no waste material such as cutting powder is generated. In addition, the depth (height) of the ridge 24 can be set without being limited by the number of the ridges 24 or the circumferential length. Therefore, as shown in Table 1, the rotational torque strength of the wheel gear 12 with respect to the fixed rotating shaft 14 can be increased.

Each of the ridges 24 of the ridge 22 has a substantially rectangular cross section orthogonal to the axial direction of the rotating shaft 14. In this case, in the case of a serration or a parallel knurled ridge like a conventional gear gear, the rotating torque between the rotating shaft 14 and the wheel gear 12 is received on a slope having a saw-like mountain, so that the rotating torque strength is increased. The adhesive strength between the side surface of the ridge 24 and the contact surface of the resin material partially depends on the adhesive strength, and a sufficiently large rotational torque intensity cannot be obtained.

On the other hand, in the gear gear 10 according to the first embodiment, since the cross-sectional shape of each ridge 24 of the ridge portion 22 is formed to be substantially rectangular, the portion of the ridge 24 is formed. Is in a state of contact with the surface substantially perpendicular to the rotation direction of the wheel gear 12 with respect to the rotation shaft 14 (a state received on the side surface of the ridge 24). That is, unlike the conventional case, since the wheel gear 12 is not received on a slope having a serrated peak, the rotational torque strength of the wheel gear 12 with respect to the rotating shaft can be further increased.

In addition, since the rotational torque strength of the wheel gear 12 with respect to the rotating shaft can be increased, the axial length of the ridge 24 can be reduced. As a result, as shown in FIG.
0) Height A of the boss portion 34 of the surrounding wheel gear 12
Can be greatly reduced as compared with the related art. Therefore, when molding the wheel gear 12 with the resin material, the resin volume of the boss portion 34 is small. For this reason, the deformation of the wheel gear 12 due to the so-called “sink” after the thermal curing as shown by the broken line in FIG. 7A and the so-called “sledding” after the thermal curing as shown by the broken line in FIG. 7B is small. Therefore, the teeth of the wheel gear 12 do not mesh with the worm gear 42, the backlash does not increase, and no noise is generated when the gear is driven.

Further, the wheel gear 1 of the rotating shaft 14
2, the flange 26 is formed by cold forging at the end of the ridge 22 on the die pressing side by the same cold forging as the formation of the ridge 22. Part 20
The resin material of the boss portion 34 of the wheel gear 12 is fixed to the rotary shaft 14 while being hooked on the flange portion 26 in the axial direction. Therefore, sufficient strength can be obtained even in the axial direction (the direction in which the ridge 22 is pressed against the mold).

Since the end of the protruding portion 22 opposite to the die pressing side is originally formed by the protruding portion, the resin material of the boss portion 34 of the wheel gear 12 is fixed in a state of being hooked here. Also, it is possible to secure the strength of removal in the axial direction (in the direction opposite to the mold pressing side).

As described above, the gear gear 10 according to the present embodiment has a configuration in which the wheel gear 12 made of a resin material is fixed to the metal rotary shaft 14 by integral molding. The rotational torque intensity between the rotating shaft 14 and the wheel gear 12 can be made sufficiently large, and the wheel gear 12 after being fixed can be made small.
2. Reduce the cost by reducing the amount of resin material for forming,
In addition, downsizing can be achieved.

In the above-described embodiment, a ridge 22 having a smaller diameter than the main body of the rotary shaft 14 is formed on the gear fixing portion 20 of the rotary shaft 14, and an end of the ridge 22 is formed at the end of the ridge 22. Although the configuration is such that the flange 26 and the stepped portion 28 are formed, the configuration of the gear fixing portion 20 (the shape of the ridge 22 and the position at which the flange 26 is formed, etc.) is not limited thereto, and may be other shapes. There may be.

For example, like a rotating shaft 50 shown in FIG. 8, a protrusion 52 having the same diameter as that of the main body is provided, and an end of a groove 55 formed between the protrusions 54 is closed to serve as a retaining portion. The flange portion 56 and the stepped portion 58 may be formed.

In the above-described embodiment, the ridges 22 of the gear fixing portion 20, that is, the plurality of ridges 24 are formed in parallel with the axial direction of the rotating shaft 14, but the present invention is not limited to this. 9, a ridge portion 74 formed with a plurality of ridges 76 helically twisted along the axial direction, such as a gear fixing portion 72 of a rotating shaft 70, and pressing the ridge portion 74 with a mold. It may be configured to have a flange 78 as a retaining portion formed at the end on the side. Also in this rotating shaft 70, the rotating torque strength of the wheel gear 12 with respect to the rotating shaft can be increased, and sufficient strength of the rotating shaft 70 in the axial direction with respect to the wheel gear 12 can be obtained. be able to.

Further, in the above-described embodiment,
The flange 26 as a retaining portion of the gear fixing portion 20 is
Although the configuration is formed at the end on the mold pressing side of No. 2, that is, at the axial end of the rotary shaft 14, the location and shape of the retaining portion are not limited to this, and other configurations may be used.

For example, like a rotating shaft 80 shown in FIG.
The gear fixing portion 82 is plastically deformed by cold forging that presses the mold from the axial direction, and the ridge portion 84 is formed with a plurality of ridges 86 along the axial direction, and the ridge portion 84 is formed. A flange 88 as a retaining portion formed at the front end of the ridge portion 84 by ironing by pushing out the groove at that time may be adopted.

Further, for example, like a rotating shaft 90 shown in FIG. 11, a gear fixing portion 92 is plastically deformed by cold forging which presses a mold from the axial direction to form a plurality of ridges 96 along the axial direction. Ridge 94 (projection ridge 96) with the projection ridge 94, which is extruded when the ridge 96 is formed.
And a projection 98 as a retaining portion, which is formed so as to be continuous with the ridge 96 at the axial center portion of the projection.

Further, for example, like a rotating shaft 100 shown in FIG. 12, a gear fixing portion 102 is plastically deformed by cold forging for pressing a mold from the axial direction, and a plurality of ridges 1 along the axial direction.
06, and the axial center of the ridge 104 (protrusion 106) formed by rolling at the same time as the step of forming the screw portion 18 by rolling after forming the ridge 104. Groove 108 as a retaining portion formed in the portion
And a configuration having the following. In the rotating shaft 100, the step of forming the flange portion 26 by further pushing and ironing the end of the ridge portion 22 on the mold pressing side as in the rotating shaft 14 according to the above-described embodiment can be omitted. , The number of steps and equipment costs can be reduced.

For example, as in a rotating shaft 110 shown in FIG. 13, a gear fixing portion 112 includes a ridge 114 having a plurality of ridges 116 formed thereon, and a screw formed by rolling the ridges 114 after forming the ridges 114. It may be configured to have a flange portion 118 as a retaining portion formed by rolling at the same time as the step of forming the portion 18 and formed on the axial front side of the ridge portion 114 (the ridge portion 116). Also in this rotating shaft 110, the flange portion 118 can be formed simultaneously with the step of forming the screw portion 18 by rolling, so that the number of steps and equipment costs can be reduced.

Further, for example, like a rotating shaft 120 shown in FIG. 14, a gear fixing portion 122 is plastically deformed by cold forging that presses a mold from the axial direction, and a plurality of ridges 1 along the axial direction are formed.
26 is formed, and the groove 12 as a retaining portion further formed in a groove portion 125 of the protrusion 124.
8 may be provided.

In the embodiments shown in FIGS. 11, 12, and 14, the retaining portions are formed on the ridges 94, 104, and 124, so that the gear fixing portions 92, 102, and 122 in the axial direction are formed. The length can be shortened, and the resin volume of the boss portion 34 when the wheel gear 12 is integrally formed can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially broken schematic perspective view showing a gear gear according to an embodiment of the present invention and a wiper motor for a wiper device configured by applying the gear gear.

FIG. 2 is a sectional view showing a configuration of a gear gear according to the embodiment of the present invention.

FIG. 3 is a front view showing a configuration of a rotating shaft of the gear gear according to the embodiment of the present invention.

FIG. 4 is a sectional view of a ridge provided on a rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 5 is a process chart showing a procedure for manufacturing the rotating shaft of the gear gear according to the embodiment of the present invention.

FIG. 6 is a sectional view showing a wheel gear of the gear gear according to the embodiment of the present invention.

FIG. 7 is a sectional view showing a wheel gear of the gear gear according to the embodiment of the present invention.

FIG. 8 is a front view showing another example of the rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 9 is a perspective view showing another example of the rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 10 is a perspective view showing another example of the rotating shaft of the gear gear according to the embodiment of the present invention.

FIG. 11 is a perspective view showing another example of the rotating shaft of the gear gear according to the embodiment of the present invention.

FIG. 12 is a perspective view showing another example of the rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 13 is a perspective view showing another example of the rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 14 is a perspective view showing another example of the rotation shaft of the gear gear according to the embodiment of the present invention.

FIG. 15 is a front view showing a rotation shaft of a conventional gear gear.

FIG. 16 is a cross-sectional view showing serrations and ridges of a parallel knurl provided on a rotating shaft of a conventional gear gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gear gear 12 Wheel gear 14 Rotating shaft 20 Gear fixing part 22 Protrusion part 24 Protrusion part 26 Flange part 30 Gear part 34 Boss part 40 Wiper motor

Claims (3)

[Claims] 1. A gear gear in which a wheel gear made of a resin material is fixed to a metal rotary shaft by integral molding, wherein the rotary shaft is plastically deformed by cold forging that presses a mold from an axial direction. A gear having a plurality of ridges formed along the axial direction on the outer peripheral surface, and a retaining portion formed along the circumferential direction adjacent to the ridge or the ridge. The wheel gear includes a disk-shaped gear portion having gear teeth formed on a peripheral edge thereof, and a boss portion for integrally fixing the gear portion to the gear fixed portion of the rotating shaft. A gear gear, comprising: 2. The gear gear according to claim 1, wherein each of the ridges of the ridge has a substantially rectangular cross-sectional shape perpendicular to the axial direction of the rotation shaft. 3. The locking portion of the rotating shaft is a flange formed by ironing by further pushing out the end of the protrusion on the mold pressing side. 2. The gear gear according to item 2.