KR20110114051A - Worm wheel for electric power steering system and method for manufacturing the same - Google Patents

Worm wheel for electric power steering system and method for manufacturing the same Download PDF

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Publication number
KR20110114051A
KR20110114051A KR1020100033463A KR20100033463A KR20110114051A KR 20110114051 A KR20110114051 A KR 20110114051A KR 1020100033463 A KR1020100033463 A KR 1020100033463A KR 20100033463 A KR20100033463 A KR 20100033463A KR 20110114051 A KR20110114051 A KR 20110114051A
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KR
South Korea
Prior art keywords
worm wheel
blank
electric power
insert
power assisted
Prior art date
Application number
KR1020100033463A
Other languages
Korean (ko)
Inventor
김성윤
Original Assignee
주식회사 만도
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 만도 filed Critical 주식회사 만도
Priority to KR1020100033463A priority Critical patent/KR20110114051A/en
Publication of KR20110114051A publication Critical patent/KR20110114051A/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0442—Conversion of rotational into longitudinal movement
    • B62D5/0454—Worm gears
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H57/02—Gearboxes; Mounting gearing therein
    • F16H57/039—Gearboxes for accommodating worm gears
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2304/00—Optimising design; Manufacturing; Testing
    • B60Y2304/05—Reducing production costs, e.g. by redesign
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2306/00—Other features of vehicle sub-units
    • B60Y2306/09—Reducing noise
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H57/02—Gearboxes; Mounting gearing therein
    • F16H57/021—Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings
    • F16H2057/0213—Support of worm gear shafts

Abstract

The present invention relates to a worm wheel of an electric power assisted steering device and a method for manufacturing the same. The worm wheel includes a blank having a hollow in which a steering shaft is inserted, and a blank in which a tooth shape corresponding to a worm gear is formed on the outer peripheral surface of the boss. Including, but the blank is provided with an insert of the blank and other elastic material, so that the noise is greatly reduced to minimize the noise transmitted to the steering shaft and the interior of the vehicle.

Description

Worm wheel for electric power assisted steering device and manufacturing method thereof {Worm wheel for electric power steering system and method for manufacturing the same}

The present invention relates to a worm wheel of the electric power assisted steering device and a manufacturing method thereof, and more particularly, by inserting an insert made of an elastic material into a blank of the worm wheel to insert molding, thereby generating noise generated when the steering device is operated according to driving. It relates to a worm wheel and a manufacturing method of the electric power assisted steering apparatus that can reduce the.

Recent technical trends of the steering apparatus provided in the vehicle has been researched and developed in the direction of pursuing the convenience of the driver with safety, such as stability of the steering state and smooth and comfortable steering. According to this development trend, various power assist steering devices, such as hydraulic or electric, are being developed as a way to improve the driver's steering feeling.The electric power is reduced due to the advantages of lighter electric, less energy consumption and improved vehicle fuel economy than hydraulic. The use of auxiliary steering devices is on the rise.

In general, the electric power assist steering device assists the driver's steering torque by driving the motor in the electronic control device according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor, thereby providing a light and comfortable steering state at low speed driving. In addition, it provides a heavy and stable steering state at high speeds, and provides steering performance to maintain the optimal steering feeling for the driver, such as enabling rapid steering operation in response to sudden emergency situations.

The electric power assisted steering device can be divided into various types according to the mounting position. The column type electric power assisted steering device is used to fix a steering shaft connecting the steering wheel of the driver's seat and the gearbox at the bottom of the vehicle to the vehicle body. By installing a power assist steering device having an electric motor in the column portion, the rotational force of the steering wheel operated by the driver can be transmitted to the gearbox by the power assist steering device.

1 is a cross-sectional view showing the main structure of a column type electric power assisted steering apparatus used in the prior art, the worm shaft 104 is formed with a worm 102 in the middle portion, the worm bearing at both ends of the worm shaft 104 106 are respectively provided to support the worm shaft 104, the worm shaft 104 and the motor shaft 108 is connected to the structure that the worm shaft 104 is rotated by the drive of the motor 110. .

A worm wheel 114 is provided at one side of the outer diameter of the worm 102 so that the worm 102 can be separated from the worm 102 formed in the middle portion of the worm shaft 104. The worm wheel 114 is a steering wheel (not shown) operated by a driver. It is mounted on the steering shaft 112 for transmitting the rotational force of the, so that 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, which are engaged in a worm gear manner, are mounted inside the housing 116 for protection from the outside.

An 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 a steering wheel whose rotational force of the worm shaft 104 by the driving of the motor 110 is manipulated by the driver. By being added to the rotational force of the transmission to the steering shaft 112, the driver's steering driving state can be maintained smoothly and stably.

On the other hand, the electric power assisted steering device uses a worm 102 and a worm wheel 114 to transfer the driving force of the motor 110 to the steering shaft 112, as described above, such a worm 102 and worm wheel 114 ) Is made of metal and has been restricted in use due to noise or vibration occurring in the areas in contact with each other.

Accordingly, the worm shaft 104 in which the worm 102 is formed is made of a metal material such as steel, and the worm wheel 114 is formed of a plastic material in a boss made of a metal such as steel, and has a blank having teeth. It was made by integrally molding.

However, in recent years, as the steering assist force becomes higher, the wear of both worm gears increases, and as a result, backlash cannot be avoided and vibration and rattle noise occur due to such backlash, in particular, off-road. In the above), such vibrations and rattle noises are transmitted to the interior of the vehicle, causing inconvenience to the driver.

Accordingly, the present invention has been made to solve the above-mentioned problems, by inserting the insert of the elastic material into the blank of the worm wheel insert molding, the electric power to reduce the noise generated when operating the steering system in accordance with the driving It is an object of the present invention to provide a worm wheel of a power assisted steering device and a method of manufacturing the same.

In order to achieve the above object, the worm wheel of the electric power assisted steering apparatus according to the present invention includes a boss having a hollow in which a steering shaft is inserted, and a blank having a tooth portion coupled to an outer circumferential surface of the boss and corresponding to a worm gear. However, the blank is characterized in that it comprises an insert of a different material than the blank.

In addition, the method for manufacturing a worm wheel of the electric power assisted steering apparatus according to the present invention comprises the steps of forming a boss of the worm wheel by cutting the forged round bar forging and forming a plastic layer on the outside of the boss by insert molding However, inserting an insert of another material into the plastic layer to form a blank, and characterized in that it comprises a step of processing the tooth shape on the blank.

As described above, according to the present invention, the noise generated when the steering apparatus is operated by the insert provided in the blank is greatly reduced, thereby minimizing the noise transmitted to the interior of the vehicle. In addition, the worm wheel according to the present invention can reduce the transmission of the noise without a significant design change to the structure of the reducer, it is possible to obtain an excellent effect at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing the main part structure of a column type electric power assisted steering apparatus used in the related art.
2 is a perspective view showing a worm wheel and a worm of the electric power assisted steering device according to the present invention.
Figure 3 is a front and side cross-sectional view showing a state before the tooth portion of the worm wheel of the electric power assisted steering apparatus according to the present invention is processed.

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 the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

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 and a worm of the electric power assisted steering apparatus according to the present invention, Figure 3 is a front view and a side showing a state before the tooth portion of the worm wheel of the electric power assisted steering apparatus according to the present invention. It is a cross section.

As shown in these figures, the worm wheel 214 of the electric power assisted steering apparatus according to the present invention includes a boss 212 having a hollow in which a steering shaft 112 (see FIG. 1) is inserted, and the boss. It comprises a blank 216 coupled to the outer circumferential surface of 212 and having a tooth portion 218 corresponding to the worm 102.

The worm wheel 214 is a boss 212 formed by forging a metal such as steel, for example, and is formed by integrally molding a blank 216 formed of a plastic material and having a tooth portion 218.

The blank 216 is insert molded on the outer circumferential surface of the boss 212 and the tooth 218 is machined by a hobbing machine that performs gear cutting, so that the noise and It serves to prevent vibration. The plastic material of the blank 216 is polyamide 6 and polyamide in which MC (Monomer Casting) nylon, which does not contain reinforcing material, or fiber reinforcing material such as glass fiber is blended in consideration of fatigue resistance, dimensional stability, or manufacturing cost. 66, polyamide 46, polyamide 12 and the like are selected and used.

In addition, the worm wheel 214 of the electric power assisted steering apparatus according to the present invention is provided with a blank 216 with an insert 220 constituting the main feature thereof. The insert 220 is inserted into the blank 216 and molded together when the insert molding the blank 216 described above, and is then cut at regular intervals during the machining of the teeth 218 by the hobbing machine.

Insert 220 is made of an elastic material such as rubber, silicone, or even a plastic different from the material of blank 216, preferably made of ethylene acrylic rubber. This is because ethylene acrylic rubber is easy to process, has high tensile strength, and exhibits excellent heat resistance, oil resistance, low temperature flexibility, and the like.

Insert 220 has a cross-section of either a semicircle, a circle, or a polygon, and is positioned circumferentially across tooth 218. In addition, the insert 220 may be partially exposed or completely buried in the surface of the tooth portion 218 as shown in FIG. 2.

It will be described a method of manufacturing the worm wheel 214 of the electric power assisted steering apparatus according to the present invention.

First, the round bar processed by drawing is cut and a base material is produced, and the base material is cold forged to form the boss 212 of the worm wheel 214.

The plastic layer is molded by insert molding on the outer side of the boss 212, and the blank 216 of the worm wheel 214 is inserted into the plastic layer by inserting the insert 220 of the plastic layer and another elastic material. To form.

Subsequently, the toothed portion 218 is processed on the outer circumferential surface of the cured blank 216 to complete the worm wheel 114 of the present invention. Machining of the teeth 218 may be performed by a hobbing machine that performs gear cutting. In this case, as shown in FIG. 3, the inserts 220 continuously connected to the annular shape may be cut at regular intervals, and a portion may be exposed to the surface of the tooth portion 218.

To briefly describe the operation relationship of the worm wheel 214 according to the present invention, the electronic control device (not shown) provided in the vehicle is based on the data collected by the various sensors while the vehicle is running. Drive by controlling. Subsequently, the driving force from the motor 110 is transmitted to the worm 102 of the worm shaft 104, thereby rotating the wheel wheel 214 engaged with the worm 102. Since the worm wheel 214 is mounted on the steering shaft 112 which transmits the rotational force of the steering wheel (not shown) which the driver operates, the rotational force of the worm shaft 104 driven by the driving of the motor 110 eventually becomes the driver. By being added to the steering force of the steering wheel to be manipulated to be transmitted to the steering shaft 112, it is possible to maintain the steering driving state of the driver smoothly and stably.

Here, when the worm 102 and the wheel 214 are engaged, vibration and rattle noise occur for some reason such as backlash, etc. In the worm wheel 214 of the present invention, the material and characteristic impedance of the blank 216 are mutually different. The insert 220 made of another elastic material prevents the vibration or wave of one medium from being conducted to the other medium, thereby greatly reducing the noise and minimizing the noise transmitted to the steering shaft and the vehicle interior. Will be.

According to the present invention having such a structure and shape, it is possible to minimize the transmission of noise without a significant design change to the structure of the reducer, it is possible to obtain a low noise and excellent noise reduction effect.

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 foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art 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.

212: boss 214: worm wheel
216: blank 218: teeth
220: insert

Claims (8)

A boss having a hollow in which a steering shaft is inserted,
It includes a blank is coupled to the outer peripheral surface of the boss and the tooth is formed corresponding to the worm,
The blank is a worm wheel of the electric power assisted steering device having an insert of a material different from the blank. The method of claim 1,
The insert is a worm wheel of the electric power assisted steering device, characterized in that the elastic material. The method of claim 2,
The insert is a worm wheel of the electric power assisted steering device, characterized in that made of ethylene acrylic rubber. The method of claim 1,
The insert is a worm wheel of the electric power assisted steering device, characterized in that it has a cross section of a semi-circle or a circular or polygonal. The method of claim 1,
The insert is a worm wheel of the electric power assisted steering device, characterized in that the part is exposed to the surface of the tooth portion formed in the blank. Cutting the drawn round bar and forging to form a boss of the worm wheel;
Forming a blank by inserting an insert of another material into the plastic layer by insert molding the plastic layer to an outer side of the boss, and forming a blank; And
Machining the tooth into the blank;
Method of manufacturing a worm wheel of the electric power assisted steering device comprising a. The method according to claim 6,
The insert is a method of manufacturing a worm wheel of the electric power assisted steering device, characterized in that the elastic material. The method according to claim 6,
In the step of processing the tooth portion on the blank, the insert is cut at regular intervals in the annular shape, and part of the surface of the tooth portion is exposed, the manufacturing method of the worm wheel of the electric power assisted steering apparatus.
KR1020100033463A 2010-04-12 2010-04-12 Worm wheel for electric power steering system and method for manufacturing the same KR20110114051A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100033463A KR20110114051A (en) 2010-04-12 2010-04-12 Worm wheel for electric power steering system and method for manufacturing the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020100033463A KR20110114051A (en) 2010-04-12 2010-04-12 Worm wheel for electric power steering system and method for manufacturing the same

Publications (1)

Publication Number Publication Date
KR20110114051A true KR20110114051A (en) 2011-10-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020100033463A KR20110114051A (en) 2010-04-12 2010-04-12 Worm wheel for electric power steering system and method for manufacturing the same

Country Status (1)

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KR (1) KR20110114051A (en)

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