KR102017079B1 - Manufacturing method of worm wheel - Google Patents

Abstract

The present invention relates to a manufacturing method of a worm wheel, the present invention, the injection portion is injection molded into a resin composition so that the insert member and the outer member is provided on the inside, the insert member so that the insertion projection is provided on the outer peripheral side in the ring shape Insert member forming step of injection molding, outer member forming step of integrally injection molding the outer member to the outside of the insert member so that the insertion projection is inserted into the inner side of the gear tooth, inner side of the gear tooth and the insert member of the outer member by irradiating infrared laser It provides a method of manufacturing a worm wheel comprising a fusion step of fusion between the outer surface of the insertion projection.

Description

Manufacturing method of worm wheel

The present invention relates to a manufacturing method of a worm wheel, and more particularly, in the manufacturing method of the worm wheel, to increase the formability and precision of the worm wheel, and to increase the mechanical strength and durability of the worm wheel when high power is transmitted through the worm wheel for a long time stable It relates to a manufacturing method of a worm wheel to be able to manufacture a worm wheel that can be used as.

In general, among the power assisted steering apparatus mounted on a vehicle, there is an electric steering apparatus in which the steering force is controlled by the motor, which is based on the driving conditions of the vehicle detected by various sensors such as a vehicle speed sensor and a steering torque sensor. And precisely drive the torque from the motor to the steering column or pinion via the speed reducer to assist the driver in manipulating the steering wheel connected to the steering column and pinion.

Accordingly, it is possible to maintain optimal steering conditions such as providing a light and comfortable steering state at low speeds, a heavy and stable steering state at high speeds, and coping with sudden emergency situations to enable rapid steering operation. To provide steering performance.

The electric steering apparatus can be divided into various types according to the mounting position. A steering column portion for fixing the steering shaft connecting the steering wheel of the driver's seat and the gearbox at the bottom of the vehicle to the vehicle body, or the pinion coupled with the rack bar. It is a device for installing a reducer provided with a motor to the built-in gearbox portion, so that the rotational force of the steering wheel operated by the driver can be transmitted to the rack bar by the motor and the reducer.

It is sectional drawing which shows the reducer and worm wheel of the electric steering apparatus conventionally.

Such a reducer is provided with a worm shaft 104 made of metal such as steel having a worm 102 formed in an intermediate portion thereof, and worm bearings 106 are provided at both ends of the worm shaft 104 to form a worm shaft 104. The worm shaft 104 and the motor shaft 108 are connected to each other, and the worm shaft 104 is rotated by the driving of the motor 110.

A worm wheel 114 made of, for example, a resin composition is provided at one side of the outer diameter of the worm 102 so as to be engaged with the worm 102 formed at an intermediate portion of the worm shaft 104 as a reduction gear. The worm wheel 114 is operated by a driver. Is mounted on the steering shaft 112 for transmitting the rotational force of the steering wheel (not shown), the rotational force of the worm shaft 104 by the drive of the motor 110 is transmitted to the steering shaft (112). These worm wheels 114 and worm shafts 104 meshed in a worm gear manner are mounted inside the housing 116 for protection from the outside.

The electronic control device (not shown) provided in the vehicle controls the driving of the motor 110 according to the driving conditions of the vehicle, and the rotational force of the steering wheel operated by the driver is controlled by the rotational force of the worm shaft 104 by the driving of the motor 110. By being added to the steering shaft 112 is to be able to maintain the steering driving state of the driver smoothly and stably.

Here, the worm wheel of the reducer as described above serves to reduce the rotational speed of the motor to transfer to the steering shaft, a gear made of a resin composition and a gear made of a metal material as described above may be configured in pairs.

However, since such a reducer is a structure in which rotating worm shafts, worm wheels, steering shafts, and the like are engaged with each other, vibrations and noises generated by rotation are directly transmitted to the driver, and the rigidity and durability of the internal parts of the reducer, in particular, the worm wheels, are improved. If dropped or severe, there was a problem that the breakage of the parts occur.

Therefore, the present invention has been devised in the background as described above, in the manufacturing method of the worm wheel, to increase the formability and precision of the worm wheel and to increase the mechanical strength and durability of the worm wheel when the high power is transmitted through the worm wheel to be used stably for a long time The purpose is to make it possible to manufacture worm wheels.

In addition, the object of the present invention is not limited thereto, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides an annular hub positioned at the center portion, a gear portion disposed at a radially outer side and having a plurality of gear teeth formed on an outer circumferential surface thereof, and a boss connecting the outer circumferential side of the hub to the inner circumferential side of the gear portion. In the manufacturing method of the worm wheel having a gear, the injection part is injection molded into a resin composition so that the insert member and the outer member is provided on the inside, the insert member is formed by injection molding the insert member so that the insertion projection is provided on the outer peripheral side in a ring shape Step, the outer member forming step of integrally injection molding the outer member on the outer side of the insert member so that the insertion projection is inserted into the gear tooth, between the inner surface of the gear tooth of the outer member and the outer surface of the insert projection of the insert member by irradiating infrared laser It provides a method of manufacturing a worm wheel comprising a fusion step of fusion.

According to the present invention, in the manufacturing method of the worm wheel, to increase the formability and precision of the worm wheel and to increase the mechanical strength and durability of the worm wheel when a high output power is transmitted through the worm wheel to produce a worm wheel that can be used stably for a long time There is an effect that becomes possible.

1 is a cross-sectional view showing a reduction gear and a worm wheel of a conventional electric steering apparatus;
2 is a perspective view showing a worm wheel according to the manufacturing method of the present invention,
Figure 3 is a partial cross-sectional perspective view showing a part of the worm wheel according to the manufacturing method of the present invention,
Figure 4 is a perspective view showing a part of the worm wheel according to the manufacturing method of the present invention,
5 is a perspective view showing a part of the worm wheel according to the manufacturing method of the present invention,
6 is a perspective view showing a manufacturing method of the present invention,
7 is a perspective view showing a manufacturing method of the present invention,
8 is a cross-sectional view of a worm wheel according to the manufacturing method of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

Figure 2 is a perspective view showing a worm wheel according to the manufacturing method of the present invention, Figure 3 is a partial cross-sectional perspective view showing a part of the worm wheel according to the manufacturing method of the present invention, Figure 4 is a perspective view showing a part of the worm wheel according to the manufacturing method of the present invention 5 is a perspective view showing a part of a worm wheel according to the manufacturing method of the present invention, FIG. 6 is a perspective view showing a manufacturing method of the present invention, FIG. 7 is a perspective view showing a manufacturing method of the present invention, and FIG. 8 is a manufacturing method of the present invention. Cross section of the worm wheel according to.

Referring to these drawings, the manufacturing method of the worm wheel 200 according to the present invention, the annular hub 205 located in the center and the gear portion formed with a plurality of gear teeth 211 located on the outer peripheral surface in the radial direction The manufacturing method of the worm wheel 200 which has a 210 and the boss 207 which connects between the outer peripheral side of the hub 205 and the inner peripheral side of the gear part 210, The gear part 210 inserts inward. The injection molding member 220 is injection molded into a resin composition so that the outer member 215 is provided on the outer side of the member 220, and the insert member 220 is injection-molded so that the insertion protrusion 221 is provided on the outer circumferential side in a ring shape. Forming step, the outer member 215 forming step of integrally injection molding the outer member 215 on the outside of the insert member 220 so that the insertion protrusion 221 is inserted into the gear tooth 211, irradiation with an infrared laser The inner surface of the gear tooth 211 of the outer member 215 and the outer surface of the insertion protrusion 221 of the insert member 220 It comprises a fusion step of fusing.

The reducer to which the worm wheel 200 is applied as an example is transmitted through a worm shaft (see 104 in FIG. 1) and a worm wheel 200 that rotate with the driving force of the motor, and is decelerated or accelerated according to the gear ratio of the worm shaft and the worm wheel gear. The worm shaft is provided with a metal worm shaft formed with a worm gear, and a worm wheel 200 is provided at one side of the outer diameter of the worm shaft so as to be engaged with the worm gear formed on the outer circumference of the worm shaft.

In addition, such a speed reducer is mounted to an electric steering device as an example, and assists the driver's steering power by rotating the steering shaft while the worm shaft and the worm wheel 200 are interlocked by the driving force of the motor. Worm shaft bearings are fastened to both ends of the worm shaft to support rotation of the worm shaft, and the worm wheel 200 and the worm shaft interlocked with the steering shaft are embedded in the gear housing.

On the other hand, the steering shaft that transmits the steering wheel's rotational force to the rack bar when the driver operates the steering wheel is connected from the steering wheel to the gear box containing the column, the universal joint, the rack gear and the pinion gear, and the reducer is connected to the column and the gear box. It can be coupled to a built-in steering shaft (or pinion).

Therefore, when the worm shaft is rotated by the driving of the motor, the worm wheel 200 is interlocked and rotated. At this time, the worm wheel 200 is coupled to the steering shaft of the column or the steering shaft of the gearbox to assist the driver's steering force.

Here, the worm wheel 200 is integrally formed on the outer circumferential side of the hub 205, the boss 207 integrally formed on the outer circumferential side of the hub 205, the input shaft, such as a steering shaft coupled to the worm shaft And a gear unit 210 engaged with the gear unit.

The steel hub 205, which is formed in an annular shape like a ring, has an input shaft coupled to a central portion thereof, and several outer protrusions having a predetermined interval in the circumferential direction are provided on an outer circumferential surface thereof.

On the other hand, the gear portion 210 is the injection member 220 and the outer member 215 is injection molded integrally so that the insert member 220 is inserted into the outer member 215 and gear teeth 211 is engaged with the worm shaft on the outer peripheral surface Is formed.

The boss 207 is injection molded integrally between the outer circumferential side of the hub 205 and the inner circumferential side of the gear unit 210, and the insert member 220 and the outer member 215 are integrally injected as shown in FIG. 5. The hub 205 is positioned at the inner center of the molded gear unit 210 and injected into the resin composition to be integrally formed.

That is, the boss 207 is formed of any one of polyamide 6, polyamide 66, polyamide 46, and polyamide 12, and is molded by injecting a resin composition mixed with glass fiber.

The boss 207 has a plurality of ribs 207c connected in the radial direction and the circumferential direction from the inner diameter portion 207a surrounding the outer peripheral surface of the hub 205 to the outer diameter portion 207b surrounding the inner peripheral surface of the gear portion 210. ) Are integrally injection molded in the mold so that they are connected to each other.

In addition, the insert member 220 is formed so that the insertion protrusion 221 is provided on the outer circumferential side in a ring shape, the insertion protrusion 221 is formed in a plurality of spaced apart in the circumferential direction in the same arrangement as the arrangement of the gear teeth 211. It is inserted into the gear tooth 211 of the outer member 215.

Therefore, the injection molding of the insert member 220 and the outer member 215 is manufactured through a fusion step so as not to be separated from the outer member 215 and to increase the bonding strength and the endurance strength.

Here, the insertion protrusion 221 is inserted into the gear tooth 211 of the outer member 215 and a plurality of support protrusions 223 are formed on one side or both sides thereof, so that the peeling strength with the outer member 215 is in the radial direction. In addition, it is also enlarged in the circumferential direction to satisfy the durability even when high power is transmitted.

The outer member 215 is integrally injection-molded in the radial direction and the axial direction of the insert member 220 so that the insertion protrusion 221 of the insert member 220 is inserted into the gear tooth 211.

The insert member 220 is formed of polyamide (PA) 66 with black pigment or polyphthalamide (PPA) with black pigment to absorb the infrared laser from the surface of the insert member 220. It is supposed to be.

The outer member 215 formed on the outer side of the insert member 220 is formed of polyamide 12 or polyamide PA 46 so that an infrared laser penetrates the outer member 215 to insert the member 220. The inner surface of the gear tooth 211 and the outer surface of the insertion protrusion 221 are welded to each other.

In addition, the insert member 220 may be injection molded by mixing 40 to 60% by weight of glass fibers in polyamide (PA) 66 with black pigment or polyphthalamide (PPA) with black pigment. have.

By adding a black pigment to the insert member 220 as described above, the infrared laser does not penetrate and the end portion of the insertion protrusion 221 is fused, and the glass member is included in the insert member 220 so that hardness, tensile strength, and elongation can be achieved. Flexural strength, high temperature properties, etc. are improved, and have excellent friction characteristics, thereby improving durability.

In addition, the outer member 215 may be injection molded by mixing 15 to 30 wt% of glass fibers in polyamide (PA) 12 or polyamide 46, and by including the glass fibers in the outer member 215, Tensile strength, elongation, flexural strength, high temperature properties, etc. are improved, and have excellent friction characteristics, thereby improving durability.

Meanwhile, the slit jig 230 having the slit 231 through which the infrared laser passes through the outer member 215 and the insert member 220 is installed on the outer surface of the gear tooth 211 of the outer member 215. The infrared laser is irradiated to the slit 231.

In addition, in this welding step, the pressing jig 245 is installed on the inner side of the insert member 220 or on the outer side of the outer member 215 and the slit in the state in which the insert member 220 and the outer member 215 are pressed in the radial direction. An infrared laser can be irradiated to 231.

That is, FIG. 8 illustrates an example of irradiating an infrared laser while pressing the slit jig 230 and the outer member 215 in the radial direction by installing the pressing jig 245 on the outer side of the outer member 215.

In this case, the worm wheel 200 is coupled to the rotary jig 241, the diode in the slit jig 230 is installed in the pressing jig 245 that receives the radial force from the drive unit 240 on the outer side of the outer member 215. An infrared laser connected through the connector 247 is irradiated to the outer circumferential surface of the gear tooth 211 through the slit 231.

8 illustrates an example of a manufacturing method of welding the outer member 215 and the insert member 220 in the state where injection molding of the worm wheel 200 is completed, but is not necessarily limited thereto. In the case of installing the pressure jig in the drawing, although not shown in the drawing, the tapered cylindrical pressure jig is press-fitted to the inside of the gear portion 210 before the boss 207 is ejected in the state where the gear portion 210 is formed. Likewise, the outer member 215 and the insert member 220 may be fused.

In addition, by irradiating the infrared laser while pressing the outer member 215 and the insert member 220 in the radial direction, the end of the insert member 220 is melted while the outer member 215 and the insert member 220 are in close contact with each other. While the fusion with the outer member 215 is made quickly.

Here, the slit jig 230 is installed in close contact with the outer surface of the gear tooth 211, the insertion projection 221 of the insert member 220 as shown in Figure 7 in the radial direction on the outer surface of the gear tooth 211. Slits 231 having the same size are formed at positions corresponding to the projected positions.

Therefore, only the end of the insertion protrusion 221 of the insert member 220 is fused, and unnecessary melting does not occur at other portions of the insert member 220, so that physical properties such as hardness and tensile strength are not generated. .

The slit jig 230 is formed in an arc shape having the same curvature as the outer circumferential surface of the gear tooth 211 to be in close contact with the outer circumferential surface of the gear tooth 211.

In addition, the slit jig 230 may be installed in two or more regions of the gear teeth 211, and the slits 231 are spaced apart in the circumferential direction according to the number of gear teeth 211 in which the slit jig 230 is installed. In the exemplary embodiment of the present invention, three slits 231 are provided so that three gear teeth 211 are fused at the same time.

In addition, in the photograph of FIG. 9, an empty space is formed between the end of the insertion protrusion 221 of the insert member 220 and the inner surface of the gear tooth 211 in the state before fusion is performed, as shown in FIG. 10. The outer member 215 and the insert member 220 are fused by an infrared laser through the 230, so that the gap between the end of the insertion protrusion 221 of the insert member 220 and the inner surface of the gear tooth 211 is closely contacted. do.

The empty space is formed between the end of the insertion protrusion 221 of the insert member 220 and the inner surface of the gear tooth 211 is caused by the shrinkage difference after the injection molding, or the flow of resin composition during injection The insert member 220 and the outer member 215 are closely molded to each other through the fusion step as described above.

Therefore, it is possible to maintain a constant friction force during the rotation operation between the worm wheel 200 and the worm, and wear or damage of the gear tooth 211 is reduced even when the durability is advanced.

According to the present invention, in the manufacturing method of the worm wheel, to increase the formability and precision of the worm wheel and to increase the mechanical strength and durability of the worm wheel when a high output power is transmitted through the worm wheel to produce a worm wheel that can be used stably for a long time There is an effect that becomes possible.

In the above description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

200: worm wheel 205: hub
210: gear portion 211: gear teeth
215: outer member 220: insert member
221: insertion protrusion 223: support protrusion
230: slit jig 231: slit

Claims (10)

In the manufacturing method of the worm wheel comprising an annular hub located in the center, a gear portion located in the radially outer side, a plurality of gear teeth formed on the outer peripheral surface, and a boss connecting between the outer peripheral side of the hub and the inner peripheral side of the gear portion. ,
The gear part is injection molded into a resin composition to be provided with an insert member on the inside and an outer member on the outside,
An insert member forming step of injection molding the insert member so that an insertion protrusion is provided on an outer circumferential side in a ring shape;
An outer member forming step of integrally injection molding the outer member to the outside of the insert member so that the insertion protrusion is inserted into the gear tooth;
And a welding step of welding the inner surface of the gear tooth of the outer member and the outer surface of the insertion protrusion of the insert member by irradiating an infrared laser,
The insert member is formed of polyamide (PA) 66 with black pigment or polyphthalamide (PPA) with black pigment, and the outer member is polyamide (PA) 12 without black pigment. Or polyamide 46 with no black pigment added,
In the fusion step, a slit jig provided with a slit through which the infrared laser passes is installed on the outer surface of the gear teeth of the outer member and irradiated with the infrared laser, so that the infrared laser passes through the outer member and the insert A method of manufacturing a worm wheel, characterized in that only the end of the insertion protrusion of the member is fused. The method of claim 1,
The boss is a manufacturing method of a worm wheel, characterized in that the injection molding between the outer peripheral side of the hub and the inner peripheral side of the gear portion integrally formed with a resin composition. delete The method of claim 1,
The insert member is a manufacturing method of a worm wheel, characterized in that the glass fiber is injection molded by mixing 40 to 60% by weight. The method of claim 1,
The outer member is a manufacturing method of a worm wheel, characterized in that the injection molding by mixing the glass fiber 15 to 30% by weight. delete The method of claim 1,
In the fusion step, the production of a worm wheel, characterized in that the pressing jig is installed on the inner side of the insert member or the outer member, and irradiating the laser to the slit while pressing the insert member and the outer member in the radial direction. Way. The method of claim 1,
The slit jig is in close contact with the outer surface of the gear teeth and the manufacturing method of the worm wheel, characterized in that the slit is formed at a position corresponding to the position projected in the radial direction on the outer surface of the gear teeth. The method of claim 1,
The slit jig is formed in a circular arc shape having the same curvature as the outer peripheral surface of the gear teeth. The method of claim 1,
The slit jig is installed in two or more areas of the gear teeth, the slit jig manufacturing method characterized in that the slit is spaced apart in the circumferential direction according to the number of gear teeth is installed.

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