CN117734813A

CN117734813A - Tooth-shaped part of automobile steering system and manufacturing method thereof

Info

Publication number: CN117734813A
Application number: CN202311841272.XA
Authority: CN
Inventors: 莫艺贤; 李广键
Original assignee: Ming Hao Auto Metal Parts Guangzhou Co ltd
Current assignee: Ming Hao Auto Metal Parts Guangzhou Co ltd
Priority date: 2023-12-28
Filing date: 2023-12-28
Publication date: 2024-03-22

Abstract

The application discloses a tooth-shaped part of an automobile steering system and a manufacturing method thereof, wherein the tooth-shaped part of the automobile steering system comprises a part body, wherein the part body is tubular, a through hole which is coaxially arranged with a central axis of the part body is formed in the part body, a polish rod part and a tooth-shaped part which are connected are arranged on the outer side surface of the part body, the surface of the polish rod part is smooth, and teeth which extend along the axial direction of the part body are arranged on the surface of the tooth-shaped part; wherein the tooth profile width of the teeth gradually increases from inside to outside along the radial direction of the part body. According to the method, the traditional CNC cutting process is replaced by the cold forging process, the processing efficiency in mass production is improved, and compared with the cutting process, the loss of the cold forging process to raw materials is less, so that production data can be saved, and the production cost is reduced. The application relates to the technical field of automobile manufacturing.

Description

Tooth-shaped part of automobile steering system and manufacturing method thereof

Technical Field

The application relates to the technical field of automobile manufacturing, in particular to a tooth-shaped part of an automobile steering system and a manufacturing method thereof.

Background

The steering system of a vehicle is an important part of the vehicle control system for controlling the forward direction of the vehicle. In general, a steering system includes a steering wheel, a rotating shaft and a rotating axle, the steering wheel is driven by a driver to rotate, torque is transmitted to the rotating shaft, and the rotating shaft is connected with the rotating axle through direct connection or after the torque is increased by a transmission mechanism, so that wheels are finally deflected to change the advancing direction of the vehicle.

Since the steering system of an automobile extends from the cab to the wheels, it needs to pass through the chassis. In order to reduce interference to other parts of the chassis and ensure enough strength and rigidity of the parts of the steering system, the parts of the steering system mostly adopt an integrated special-shaped structure. For example, the connection of the rotary shaft to the steering wheel or the rotary bridge is generally provided with a toothed element which serves to transmit torque. The tooth-shaped part is integrally in a circular tube shape, teeth are arranged on the outer side face in a surrounding mode, and the tooth-shaped part can be connected with other parts in a nested mode through the teeth, so that torque is transmitted.

In the actual production stage, a CNC machining center is generally adopted to cut off the round steel pipe to obtain a blank, and then the surface of the blank is cut to form the teeth on the outer side face. Although parts with higher precision can be obtained, the machining efficiency is low, and the efficiency requirement of mass production is difficult to meet. Secondly, the cutting process consumes more raw materials, and the problem is particularly serious in mass production, which is unfavorable for reducing the production cost.

Disclosure of Invention

The purpose of the application is to solve at least one of the technical problems existing in the prior art, provide a tooth-shaped part of an automobile steering system and a manufacturing method thereof, and can improve the production efficiency of the tooth-shaped part and reduce the production cost.

According to an embodiment of a first aspect of the present application, there is provided a toothed part of an automotive steering system, comprising:

the part comprises a part body, wherein the part body is tubular, a through hole which is coaxially arranged with the central axis of the part body is formed in the part body, a polish rod part and a tooth-shaped part which are connected are arranged on the outer side surface of the part body, the surface of the polish rod part is smooth, and teeth which extend along the axial direction of the part body are arranged on the surface of the tooth-shaped part;

wherein the tooth profile width of the teeth gradually increases from inside to outside along the radial direction of the part body.

According to an embodiment of the first aspect of the present application, further, the number of teeth is plural and distributed in a circumferential array around the central axis of the part body.

According to an embodiment of the first aspect of the present application, further, the diameter of the polish rod portion is the same as the diameter of the addendum circle of the tooth.

According to an embodiment of the first aspect of the present application, further, a slope is used to transition between the tooth bottom surface of the tooth and the polish rod portion.

According to an embodiment of the first aspect of the present application, further, the slope forms an angle of 40 ° to 60 ° with the central axis of the part body.

According to a second aspect of the present application, there is provided a method for manufacturing a tooth-shaped part for producing the above-described automotive steering system, comprising:

cutting off the round pipe-shaped material by using cutting equipment to obtain a blank;

upsetting the blank to increase the diameter of the blank;

respectively carrying out cold forging on two end faces of the blank to generate a preformed groove;

respectively performing backward extrusion punching on the two preformed grooves to obtain preformed inner holes;

drilling two preformed inner holes to obtain the through holes;

and carrying out cold forging on the outer surface of the blank to obtain the tooth-shaped part.

According to an embodiment of the second aspect of the present application, further, the blank is subjected to chamfering treatment on the end face after cutting.

According to an embodiment of the second aspect of the present application, further, when cold forging the blank to obtain the tooth form portion, cold forging is performed by using a vertical cold forging apparatus, the vertical cold forging apparatus includes a die and a punch, a die core is disposed in the die, and the punch is used for driving the blank to press against the die core to generate the tooth form portion.

According to an embodiment of the second aspect of the present application, further, the male die comprises a push tube and a core rod, the core rod being capable of extending into the through hole to prevent the blank from collapsing inwards during cold forging, the push tube being in contact with an end of the blank and exerting a force.

According to an embodiment of the second aspect of the present application, the die further comprises a die ejector pin slidably connected to the die and capable of extending into the die core for exerting a force on the blank to push it out of the die core.

The beneficial effects of the embodiment of the application at least comprise: according to the method, the traditional CNC cutting process is replaced by the cold forging process, the processing efficiency in mass production is improved, and compared with the cutting process, the loss of the cold forging process to raw materials is less, so that production data can be saved, and the production cost is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following description will simply explain the drawings that are required to be used in the description of the embodiments. It is apparent that the drawings described are only some embodiments, but not all embodiments, of the present application, and that other designs and drawings can be obtained from these drawings by those skilled in the art without inventive effort.

FIG. 1 is a cross-sectional view of a toothed part of an automotive steering system according to a first aspect of the present application;

FIG. 2 is a cross-sectional view at A-A in FIG. 1;

FIG. 3 is a cross-sectional view of a vertical cold forging apparatus in a manufacturing method according to an embodiment of a second aspect of the present application;

FIG. 4 is a schematic diagram of steps a to d in the manufacturing method according to the embodiment of the second aspect of the present application;

fig. 5 is a schematic diagram of steps e to g in the manufacturing method according to the embodiment of the second aspect of the present application.

Reference numerals: 100-part body, 110-polish rod part, 120-tooth part, 121-tooth part, 130-slope part, 200-through hole part, 300-blank part, 400-preformed groove part, 500-preformed inner hole part, 600-concave die part, 610-die core part, 620-concave die ejector pin part, 700-convex die part, 710-push tube part and 720-core rod part.

Detailed Description

Reference will now be made in detail to the present embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein the purpose of the accompanying drawings is to supplement the description of the written description section with figures, so that one can intuitively and intuitively understand each technical feature and overall technical scheme of the present application, but not to limit the scope of protection of the present application.

In the description of the present application, it should be understood that references to orientation descriptions, such as directions of up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the drawings, are merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of the present application, the meaning of a number is one or more, the meaning of a number is two or more, greater than, less than, exceeding, etc. are understood to not include the present number, and the meaning of a number above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present application, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present application can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical solution.

In this regard, the application provides a tooth-shaped part of an automobile steering system and a manufacturing method thereof, wherein a cold forging process is used for replacing a traditional CNC cutting process, so that the processing efficiency of the tooth-shaped part in mass production is improved, and compared with a cutting process, the loss of raw materials caused by the cold forging process is less, thereby saving production data and reducing production cost.

Referring to fig. 1, a toothed part of an automotive steering system in an embodiment of a first aspect of the present application includes a part body 100. The part body 100 is tubular, in particular circular tube, and is internally provided with a through hole 200 coaxially arranged with the central axis thereof, so that on one hand, the dead weight of the part body 100 can be reduced, and on the other hand, the part body is also used for being connected with an external part in a nested manner. Specifically, in order to make the external part more easily inserted into the through hole 200, the openings at both ends of the through hole 200 are provided with inner chamfers, so that the external part can be conveniently slid into the through hole 200.

The outer side surface of the part body 100 is provided with a polish rod part 110 and a tooth part 120 which are connected. Wherein the surface of the polish rod portion 110 is smooth and the surface of the tooth-shaped portion 120 is provided with teeth 121 extending in the axial direction of the part body 100. The external part corresponding to the tooth-shaped portion 120 is provided with a tooth groove adapted so that the teeth 121 slide into the tooth groove when the present part body 100 is inserted into the external part, thereby enabling torque transmission through the teeth 121 and the tooth groove when the part body 100 or the external part is rotated. The polish rod portion 110 is arranged to limit the insertion depth of the part body 100, and plays a limiting role.

For the tooth profile shape of the teeth 121, it may be provided in a square, trapezoid or semicircle shape. In this embodiment, referring to fig. 2, the tooth profile of the tooth 121 is trapezoidal, and the tooth profile width of the tooth 121 gradually increases from inside to outside in the radial direction of the part body 100. If the tooth profile width of the teeth 121 gradually decreases from inside to outside along the radial direction of the part body 100, when a large torque is applied, a component force toward the inside of the part body 100 may occur on the surface of the teeth 121, and thus the part body 100 is compressed to deform the through hole 200, and even sliding teeth may occur in severe cases. Therefore, the tooth profile width of the teeth 121 in this embodiment gradually increases from inside to outside along the radial direction of the part body 100, so as to reduce the risk of slipping due to excessive torque when the external part is in nested connection with the tooth-shaped portion 120.

Further, the number of teeth 121 is plural and distributed in a circumferential array around the central axis of the part body 100, so that on one hand, the center of gravity of the part body 100 is located as far as possible at the central axis thereof, thereby reducing radial runout during rotation; on the other hand, by providing the plurality of teeth 121 to share the torsional force, the risk of occurrence of collapse due to excessive tooth root stress is reduced.

Further, the diameter of the polish rod 110 is the same as the diameter of the tip circle of the tooth 121, and the tip surface of the tooth 121 is in contact with the polish rod 110.

Further, the transition between the tooth bottom surface of the tooth 121 and the polish rod 110 is performed through the slope 130, and the slope 130 is provided to reduce the stress concentration at the connection of the tooth 121 and the polish rod 110. Specifically, the slope 130 forms an included angle of 40 to 60 ° with the central axis of the part body 100, and both ends of the slope 130 are provided with arc transition chamfers, so that they transition to the polished rod portion 110 and the tooth bottom surfaces of the teeth 121 more smoothly.

In a second aspect of the present application, a method of manufacturing a toothed part for an automotive steering system is provided. In the manufacturing method, a vertical cold forging apparatus is included to machine the tooth 120 on the part body 100. Referring to fig. 3, the vertical cold forging apparatus includes a female die 600 and a male die 700, which can be moved toward and away from each other by a power apparatus. After the blank 300 is mounted to the female die 600, pressure is applied to the blank 300 by the male die 700 so that the blank 300 forms the tooth 120 in the female die 600. Specifically, a mold core 610 is disposed in the female mold 600, and the mold core 610 is in interference fit with the female mold 600, so that the two are firmly connected. The core 610 is provided with a protruding strip for forming the teeth 121, and when the blank 300 is deformed by pressing in the core 610, the material flows on the surface of the protruding strip, so that the surface of the blank 300 forms a plurality of elongated teeth 121.

Further, the punch 700 includes a push tube 710 and a core rod 720, and the core rod 720 protrudes outward as compared to the push tube 710. The core rod 720 can be inserted into the through-hole 200 during the approach of the punch 700 to the blank 300, and by filling the inner space of the through-hole 200, the blank 300 can be prevented from collapsing inward during the cold forging process to affect the forming size of the through-hole 200 when the blank 300 is pressed. Push tube 710 is tubular in shape and is capable of contacting and exerting a force against the end of blank 300.

Further, the female mold 600 includes a female mold ejector 620, and the female mold ejector 620 is slidably connected to the female mold 600 and can extend into the mold core 610. After cold forging of the blank 300 is completed, the female die ejector pins 620 extend into the die cores 610 and apply force to the ends of the blank 300, driving the blank 300 to move so as to push out the blank from the die cores 610, thereby facilitating the demolding operation.

It will be readily appreciated that the cavity pin 620 may also push other components into the core 610 to indirectly push the blank 300 within the core 610, thereby completing the demolding of the blank 300.

Based on the vertical cold forging equipment, the manufacturing method comprises the following steps:

s100, referring to a of FIG. 4, cutting a round pipe-shaped material by using cutting equipment to obtain a blank 300; and referring to fig. 4 b, chamfering the end of the blank 300 in preparation for subsequent upsetting and deburring the cut-out port of the blank 300;

s200. referring to fig. 4 c, upsetting the blank 300 to increase the diameter of the blank 300 to approximate the outer diameter requirement of the finished part;

s300, referring to d of fig. 4, cold forging is respectively carried out on two end faces of the blank 300 to generate a preformed groove 400, and punching positions are marked for subsequent punching;

s400, referring to e of FIG. 5, performing backward extrusion punching on the two preformed grooves 400 to obtain preformed inner holes 500, wherein coaxiality of the two preformed inner holes 500 is maintained, and preparation is made for subsequent punching of the two preformed inner holes 500 to form the through holes 200;

s500, referring to f of FIG. 5, drilling through two preformed inner holes 500 by using a CNC machining center or a drill floor to obtain a through hole 200;

s600. referring to fig. 5 g, the outer surface of the blank 300 is cold-forged by the vertical cold forging apparatus described above to obtain the tooth 120.

Finally, the CNC machining center is utilized to repair the tooth-shaped part of the steering system of the automobile, and burrs and flaws on the surface of the part body 100 and in the through hole 200 are removed.

Further, for the circular tube-shaped material used in the application, phosphating, wiredrawing and annealing treatment are carried out on the material before cutting, so that the ductility of the material is improved, and the subsequent cold forging operation is facilitated.

While the preferred embodiments of the present application have been illustrated and described, the present invention is not limited to the embodiments, and various equivalent modifications and substitutions can be made by one skilled in the art without departing from the spirit of the present application, and these are intended to be included within the scope of the present claims.

Claims

1. A toothed part for an automotive steering system, comprising:

the part comprises a part body (100), wherein the part body (100) is tubular, a through hole (200) which is coaxially arranged with the central axis of the part body is formed in the part body, a polish rod part (110) and a tooth-shaped part (120) which are connected are arranged on the outer side surface of the part body (100), the surface of the polish rod part (110) is smooth, and teeth (121) which extend along the axial direction of the part body (100) are arranged on the surface of the tooth-shaped part (120);

wherein the tooth profile width of the teeth (121) gradually increases from inside to outside along the radial direction of the part body (100).

2. The toothed part of an automotive steering system according to claim 1, characterized in that: the number of teeth (121) is plural and distributed in a circumferential array around the central axis of the part body (100).

3. The toothed part of an automotive steering system according to claim 1, characterized in that: the diameter of the polish rod part (110) is the same as the diameter of the top circle of the tooth (121).

4. The toothed part of an automotive steering system according to claim 1, characterized in that: the tooth bottom surface of the tooth (121) is in transition with the polish rod part (110) through a slope (130).

5. The toothed part of an automotive steering system of claim 4, wherein: the slope (130) forms an included angle of 40-60 degrees with the central axis of the part body (100).

6. A method of manufacturing a toothed part for producing an automotive steering system according to any one of claims 1 to 5, characterized by comprising:

cutting the round pipe-shaped material by using cutting equipment to obtain a blank (300);

upsetting the blank (300) such that the diameter of the blank (300) increases;

respectively carrying out cold forging on two end faces of the blank (300) to generate a preformed groove (400);

respectively performing backward extrusion punching on the two preformed grooves (400) to obtain preformed inner holes (500);

-drilling through two of said preformed inner bores (500) obtaining said through holes (200);

-cold forging the outer surface of the blank (300) to obtain the tooth (120).

7. The manufacturing method according to claim 6, characterized in that: the blank (300) is subjected to chamfering treatment on the end face after cutting.

8. The manufacturing method according to claim 6, characterized in that: when the blank (300) is cold forged to obtain the tooth-shaped part (120), a vertical cold forging device is adopted to perform cold forging, the vertical cold forging device comprises a female die (600) and a male die (700), a die core (610) is arranged in the female die (600), and the male die (700) is used for driving the blank (300) to press against the die core (610) so as to generate the tooth-shaped part (120).

9. The manufacturing method according to claim 8, characterized in that: the punch (700) includes a push tube (710) and a mandrel (720), the mandrel (720) being capable of extending into the through hole (200) to prevent the blank (300) from collapsing inwardly during cold forging, the push tube (710) contacting and exerting a force on an end of the blank (300).

10. The manufacturing method according to claim 8, characterized in that: the female die (600) comprises a female die ejector pin (620), wherein the female die ejector pin (620) is in sliding connection with the female die (600) and can extend into the die core (610) and is used for exerting force on the blank (300) to push the blank out of the die core (610).