阅读说明：本技术 淬火件转向节的加工工艺及其夹具 (Machining process and clamp for quenching part steering knuckle ) 是由 张运军 秦健 邵光保 杨悦 刘海军 徐生荣 李龙群 张鹏 杜鑫 刘舒豪 于 2020-05-28 设计创作，主要内容包括：本发明涉及转向节加工技术领域,公开了淬火件转向节的加工工艺,包括以下步骤：S1,对法兰盘、止口台、内轴颈以及外轴颈进行第一步车处理；S2,对内轴颈进行淬火处理；S3,对法兰盘、止口台、内轴颈以及外轴颈进行第二步车处理；S4,对止口台进行钻孔以及攻丝。本发明能够延长刀片的使用寿命。(The invention relates to the technical field of steering knuckle processing, and discloses a processing technology of a quenching part steering knuckle, which comprises the following steps: s1, carrying out first-step vehicle processing on the flange plate, the spigot platform, the inner journal and the outer journal; s2, quenching the inner shaft neck; s3, carrying out second-step turning treatment on the flange plate, the spigot platform, the inner journal and the outer journal; and S4, drilling and tapping the spigot boss. The invention can prolong the service life of the blade.)

1. The machining process of the quenched part steering knuckle is characterized by comprising the following steps of:

s1, carrying out first step vehicle processing on the flange plate (14), the spigot platform (17), the inner journal (18) and the outer journal (19);

s2, quenching the inner journal (18);

s3, carrying out second-step turning treatment on the flange plate (14), the spigot platform (17), the inner journal (18) and the outer journal (19);

and S4, drilling and tapping the spigot platform (17).

2. The process for machining a steering knuckle of a quenched member according to claim 1, wherein the quenching treatment in the step S2 is a medium-frequency quenching treatment.

3. A jig used in the process of machining a hardened member knuckle according to claim 1 or 2, characterized by comprising:

the supporting device comprises a supporting cylinder (1) which is horizontally arranged, wherein a circular truncated cone-shaped supporting hole (2) is horizontally arranged in an inner cavity of the supporting cylinder (1);

the positioning thimble (3) comprises a connecting part (3a) matched with the supporting hole (2) and a positioning part (3b) positioned outside the supporting cylinder (1), and the end part of the positioning part (3b) departing from the connecting part (3a) is arranged in a pointed shape;

rotate connect in driving-disc (4) on a supporting cylinder (1) outer wall, the axle center of driving-disc (4), the axle center of a supporting cylinder (1) and the axle center collineation of location thimble (3), movable dovetail (5) have been seted up on driving-disc (4), the activity is provided with in activity dovetail (5) with first dovetail (6) of activity dovetail (5) matched with, be provided with activity body (7) on first dovetail (6), still be provided with location body (8) on driving-disc (4), it is provided with regulation pole (9) to rotate on the fixed body, it passes to adjust pole (9) first dovetail (6) and with first dovetail (6) threaded connection, the length direction who adjusts pole (9) with the length direction of activity dovetail (5) is parallel.

4. The jig for use in machining of a quenched member knuckle according to claim 3, wherein one end of the movable dovetail groove (5) is located in the middle of the driving disc (4), the other end penetrates one side of the driving disc (4), and the end of the movable dovetail groove (5) penetrating the driving disc (4) is located on the same side of the positioning body (8) as the first dovetail body (6).

5. The jig used in processing of a hardened member knuckle according to claim 3, a second dovetail body (10) matched with the movable dovetail groove (5) is also movably arranged in the movable dovetail groove (5), the second dovetail body (10) is located between the first dovetail body (6) and the positioning body (8), the adjusting rod (9) penetrates through the second dovetail body (10) and is in threaded connection with the second dovetail body (10), a clamping piece (11) is arranged on the second dovetail body (10), the clamping piece (11) is movably attached to the driving disc (4), the positioning portion (3b) is close to the outer wall of the end portion of the connecting portion (3a) and is provided with an annular clamping groove (12), and the adjusting rod (9) is rotated to enable the clamping piece (11) to be clamped in the clamping groove (12) or separated from the clamping groove (12).

6. The jig for use in machining of a quenched member knuckle according to claim 5, characterized in that the connecting portion (3a) and the support cylinder (1) each have a set distance from a side of the drive plate (4) near the positioning portion (3 b).

7. The clamp used in the machining of the quenching piece steering knuckle according to claim 5, characterized in that a weight (13) is arranged on the driving disc (4), and the weight (13) and the positioning body (8) are positioned on both sides of the positioning thimble (3).

8. The clamp used in the machining of the quenching part steering knuckle is characterized in that the weight part (13) is U-shaped, the length direction of the weight part (13) is parallel to the length direction of the movable dovetail groove (5), two ends of the weight part (13) are respectively connected with the driving disc (4), the middle part of the weight part is parallel to the disc surface of the driving disc (4), and the end part, far away from the second dovetail body (10), of the clamping part (11) is movably sleeved in the middle part of the weight part (13).

Technical Field

The invention relates to the technical field of steering knuckle processing, in particular to a processing technology of a quenching part steering knuckle and a clamp thereof.

Background

A Steering Knuckle (Steering Knuckle), also known as a "claw", is one of important parts in an automobile Steering axle, and can enable an automobile to stably run and sensitively transmit the running direction. The steering knuckle is used for transmitting and bearing the front load of the automobile, supporting and driving the front wheel to rotate around the main pin so as to steer the automobile. In the driving state of the vehicle, it is subjected to a variable impact load, and therefore, it is required to have a high strength.

A conventional steering knuckle is shown in fig. 7, and mainly includes a flange 14 (also called a large disc), a first ear 15 and a second ear 16 connected to two ends of one side of the flange 14 (the length of the first ear 15 is longer than that of the second ear 16), and a spigot boss 17, an inner journal 18 and an outer journal 19 on the other side of the flange 14, wherein a tapered rod 20 is provided between the inner journal 18 and the outer journal 19, and a stub shaft 21 is provided at one end of the outer journal 19 facing away from the tapered rod 20. Currently, in several steps of machining the spigot 17, inner journal 18 and outer journal 19 portions of the knuckle, the following steps are involved: semi-finish turning of the inner journal 18, the outer journal 19, the flange plate 14 and the spigot boss 17 (through a numerical control lathe) → drilling and tapping of holes at the spigot boss 17 (through a machining center) → medium-frequency quenching of the inner journal 18 (through a quenching machine) → finish turning of the flange plate 14, the outer journal 19 and the spigot boss 17 (through a numerical control lathe).

However, the quenching insert is used for turning during finish turning, the material of the quenching insert is different from that of a common turning insert, and due to the fact that the spigot platform 17 is provided with the hole, intermittent turning can occur in the turning process, the edge is prone to breaking, damage to the insert is large, and the service life of the insert is short.

Disclosure of Invention

The invention aims to provide a machining process of a quenching part steering knuckle and a clamp thereof, and aims to solve the problem of short service life of a blade.

The technical purpose of the invention is realized by the following technical scheme: a machining process of a quenched part steering knuckle comprises the following steps:

s1, carrying out first-step vehicle processing on the flange plate, the spigot platform, the inner journal and the outer journal;

s2, quenching the inner shaft neck;

s3, carrying out second-step turning treatment on the flange plate, the spigot platform, the inner journal and the outer journal;

and S4, drilling and tapping the spigot boss.

The invention is further provided with: the quenching treatment in the step S2 is intermediate-frequency quenching treatment.

The invention also provides a clamp for machining the steering knuckle of the quenching part, which comprises the following components:

the supporting cylinder is horizontally arranged, and a circular truncated cone-shaped supporting hole is horizontally arranged in the inner cavity of the supporting cylinder;

the positioning thimble comprises a connecting part matched with the supporting hole and a positioning part positioned outside the supporting cylinder, and the end part of the positioning part departing from the connecting part is arranged in a pointed shape;

the movable dovetail is arranged on the supporting cylinder, the movable dovetail groove is formed in the driving disc, a first dovetail body matched with the movable dovetail groove is movably arranged in the movable dovetail groove, a movable body is arranged on the first dovetail body, a positioning body is further arranged on the driving disc, an adjusting rod is arranged on the fixed body in a rotating mode, the adjusting rod penetrates through the first dovetail body and is in threaded connection with the first dovetail body, and the length direction of the adjusting rod is parallel to the length direction of the movable dovetail groove.

The invention is further provided with: one end of the movable dovetail groove is located in the middle of the driving disc, the other end of the movable dovetail groove penetrates through one side of the driving disc, and the end of the movable dovetail groove penetrating through the driving disc and the first dovetail body are located on the same side of the positioning body.

The invention is further provided with: still the activity be provided with in the activity dovetail with activity dovetail matched with second dovetail body, the second dovetail position in first dovetail body with between the locating body, the regulation pole passes the second dovetail body and with second dovetail body threaded connection, be provided with joint spare on the second dovetail body, joint spare activity laminating in the driving-disc, location portion is close to seted up annular joint groove on the tip outer wall of connecting portion, rotates the regulation pole can make joint spare block in the joint groove or with the joint groove separation.

The invention is further provided with: the connecting part and the supporting cylinder are provided with a set distance from one side of the driving disc close to the positioning part.

The invention is further provided with: the driving disc is provided with a weight piece, and the weight piece and the positioning body are positioned on two sides of the positioning thimble.

The invention is further provided with: the counterweight is U-shaped, the length direction of the counterweight is parallel to that of the movable dovetail groove, two ends of the counterweight are respectively connected with the driving disc, the middle part of the counterweight is parallel to the disc surface of the driving disc, and the end part of the clamping piece, which is far away from the second dovetail body, is movably sleeved on the middle part of the counterweight.

The invention has the beneficial effects that: firstly, when the first step of turning is carried out, semi-finish turning is adopted, and then the inner journal part is subjected to intermediate frequency quenching through a quenching machine, wherein the size and the model of an intermediate frequency induction coil used in the process are optimized and reduced, and the quenching range is controlled so as to prevent the quenching range from spreading to a pre-processing part, so that the end face of the spigot joint table is too high in hardness and the service life of a cutter for drilling and tapping the hole on the spigot joint table is influenced; and then, after one side of the shaft head is milled flat (the step can be implemented or not implemented according to the actual situation), fixing the position of the steering knuckle through a clamp, carrying out second-step finish turning on a flange plate, an inner journal, an outer journal and a spigot table of the steering knuckle, and finally drilling and tapping the spigot table after finish turning is finished.

When the finish machining is carried out on the spigot platform, no hole is formed in the spigot platform, so that when the finish machining is carried out on the spigot platform, the blade (a special quenching blade which is not suitable for intermittent turning due to material reasons) does not undergo intermittent turning but is continuously carried out, the blade can be well protected, and the service life of the blade is prolonged. Moreover, when the method is used for processing, the 'fine grinding inner journal (through a cylindrical grinding machine)' and the 'fine outer journal and spigot table (through a numerical control lathe)' in the conventional processing method are combined into one-step fine turning, and the coaxiality of the knuckle can be ensured in the same-step fine turning process, so that the quality of a product is higher (if the method is carried out in two steps, namely the inner journal is subjected to fine grinding and the outer journal and the spigot table are subjected to fine turning, the axle center can generate certain deviation when the knuckle is clamped or processed twice, so that the coaxiality of the product is poorer, or the coaxiality of the outer journal relative to the inner journal, the jumping of the spigot excircle relative to the common axis of the two journals and other geometric position tolerance are difficult to ensure).

Meanwhile, it should be understood that other processing steps and methods for the knuckle are consistent with those commonly used at present, or some processing techniques known in the art are adopted, and thus, too many limitations and details are not needed here.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural view of an embodiment of the clamp used in the machining of a quenched member knuckle according to the present invention;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a first cross-sectional view of an embodiment of the fixture of the present invention used in the machining of a hardened knuckle;

FIG. 4 is an enlarged view of portion B of FIG. 3;

FIG. 5 is a second cross-sectional view of an embodiment of the fixture of the present invention used in the machining of a hardened knuckle;

FIG. 6 is a schematic structural view of an embodiment of a portion of a fixture used in the machining of a hardened member knuckle according to the present invention;

fig. 7 is a schematic structural view of a knuckle.

In the figure, 1, supporting the cylinder; 2. a support hole; 3. positioning the thimble; 3a, a connecting part; 3b, a positioning part; 4. a drive disc; 5. a movable dovetail groove; 6. a first dovetail body; 7. a movable body; 8. a positioning body; 9. adjusting a rod; 10. a second dovetail body; 11. a clamping piece; 12. a clamping groove; 13. a counterweight; 14. a flange plate; 15. a first ear portion; 16. a second ear; 17. a spigot platform; 18. an inner journal; 19. an outer journal; 20. a tapered rod; 21. the shaft head.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

A machining process of a quenched part steering knuckle is shown in figures 1 to 7 and comprises the following steps:

s1, carrying out first step vehicle processing on the flange plate 14, the spigot platform 17, the inner journal 18 and the outer journal 19;

s2, quenching the inner journal 18;

s3, carrying out second vehicle processing on the flange plate 14, the spigot platform 17, the inner journal 18 and the outer journal 19;

s4, drilling and tapping the spigot boss 17.

The quenching treatment in the step S2 is intermediate-frequency quenching treatment.

The invention discloses a processing technology of a quenching piece steering knuckle, which comprises the steps of firstly, performing semi-finish turning treatment when performing first-step turning treatment, and then performing intermediate frequency quenching on an inner journal 18 part through a quenching machine, wherein the size and the model of an intermediate frequency induction coil used in the process are optimized and reduced, and the quenching range is controlled so as to prevent the quenching range from spreading to a pre-processing part, so that the end face hardness of a spigot platform 17 is too high, and the service life of a cutter for drilling and tapping a hole on the spigot platform 17 is influenced; and then, after one side of the shaft head 21 is milled flat (the step can be implemented or not according to actual conditions), fixing the position of the steering knuckle through a clamp, carrying out secondary finish turning on the flange plate 14, the inner journal 18, the outer journal 19 and the spigot platform 17 of the steering knuckle, and finally drilling and tapping the spigot platform 17 after finish turning is finished.

Since no hole is formed in the spigot table 17 when the spigot table 17 is finished, when the spigot table 17 is partially finished, the insert (a special quenching insert which is not suitable for intermittent turning due to material) does not undergo intermittent turning but is continuously finished, so that the insert can be well protected, and the service life of the insert is prolonged. Moreover, when the method is used for processing, the 'fine grinding inner journal 18 (through a cylindrical grinding machine)' and the 'fine outer journal 19 and the spigot table 17 (through a numerical control lathe)' in the current common processing method are combined into a one-step finish turning, and the coaxiality of the knuckle can be ensured in the finish turning process in the same step, so that the quality of a product can be higher (if the finish turning is carried out in two steps, namely, the inner journal 18 is subjected to fine grinding and the outer journal 19 and the spigot table 17 are subjected to finish turning, the axle center can generate certain deviation when the knuckle is clamped or processed twice, so that the coaxiality of the product is poor, or the coaxiality of the outer journal 19 relative to the inner journal 18, the jumping of the spigot excircle relative to the common axis of the two journals and the like are difficult to ensure).

Meanwhile, it should be understood that other processing steps and methods for the knuckle are consistent with those commonly used at present, or some processing techniques known in the art are adopted, and thus, too many limitations and details are not needed here.

The invention also provides a clamp for machining the steering knuckle of the quenching part, which comprises the following components:

the supporting device comprises a supporting cylinder 1 which is horizontally arranged, wherein a circular truncated cone-shaped supporting hole 2 is horizontally arranged in an inner cavity of the supporting cylinder 1;

the positioning thimble 3 (the part contacted with the positioning thimble 3 or the external thimble is provided with a groove for skid resistance and limiting), the positioning thimble 3 comprises a connecting part 3a matched with the supporting hole 2 and a positioning part 3b positioned outside the supporting cylinder 1, and the end part of the positioning part 3b departing from the connecting part 3a is arranged in a pointed shape;

the supporting cylinder is characterized in that a driving disc 4 is rotatably connected to the outer wall of the supporting cylinder 1, the axis of the driving disc 4, the axis of the supporting cylinder 1 and the axis of the positioning ejector pin 3 are collinear, a movable dovetail groove 5 is formed in the driving disc 4, a first dovetail body 6 matched with the movable dovetail groove 5 is movably arranged in the movable dovetail groove 5, a movable body 7 is arranged on the first dovetail body 6, a positioning body 8 is further arranged on the driving disc 4, an adjusting rod 9 is rotatably arranged on the fixing body, the adjusting rod 9 penetrates through the first dovetail body 6 and is in threaded connection with the first dovetail body 6, and the length direction of the adjusting rod 9 is parallel to the length direction of the movable dovetail groove 5.

One end of the movable dovetail groove 5 is positioned in the middle of the driving disk 4, the other end of the movable dovetail groove penetrates through one side of the driving disk 4, and the end part of the movable dovetail groove 5 penetrating through the driving disk 4 and the first dovetail body 6 are positioned on the same side of the positioning body 8.

Still be provided with in the activity dovetail 5 with activity dovetail 5 matched with second dovetail 10, second dovetail 10 is located first dovetail 6 with between the locating body 8, adjust the pole 9 and pass second dovetail 10 and with second dovetail 10 threaded connection, be provided with joint spare 11 on the second dovetail 10, joint spare 11 activity laminating in driving-disc 4, location portion 3b is close to annular joint groove 12 has been seted up on the tip outer wall of connecting portion 3a, rotates adjust pole 9 and can make joint spare 11 block in joint groove 12 or with joint groove 12 separation. The connecting part 3a and the supporting cylinder 1 have a set distance with one side of the driving disc 4 close to the positioning part 3 b.

The driving disc 4 is provided with a weight member 13, and the weight member 13 and the positioning body 8 are located at two sides of the positioning thimble 3. The counterweight 13 is U-shaped, the length direction of the counterweight 13 is parallel to that of the movable dovetail groove 5, two ends of the counterweight 13 are respectively connected with the driving disc 4, the middle part of the counterweight is parallel to the disc surface of the driving disc 4, and the end part of the clamping part 11 far away from the second dovetail body 10 is movably sleeved in the middle part of the counterweight 13.

The clamp for machining the quenched part steering knuckle is mainly used for fixing the position of the steering knuckle during vehicle processing in S1 and S4, or a conventional clamp is selected according to the practical situation S1, and the clamp of the application is selected in S4, and the specific use method of the clamp is not limited too much.

When the steering knuckle is machined, firstly, the steering knuckle is moved, the middle part of one side, close to the first lug part 15 and the second lug part 16, of the connecting disc 14 is abutted against the end part of the positioning part 3b (a central hole is formed in the side part of the connecting disc 14 and is used for being matched with the positioning part 3b), then, another ejector pin is moved to abut against the end part, away from the inner shaft neck 18, of the shaft head 21 (similarly, a central hole matched with the ejector pin is also formed in the end part of the shaft head 21, and the ejector pin can be moved and positioned through a slide carriage on a lathe or in other conventional moving and positioning modes); after the two ends of the steering knuckle are firmly propped by the positioning ejector pin 3 and the ejector pin respectively, the first lug part 15 is also just positioned between the positioning body 8 and the movable body 7, at the moment, the adjusting rod 9 is rotated, the position of the adjusting rod 9 is fixed, but the adjusting rod can drive the first dovetail body 6 and the second dovetail body 10 to move;

wherein the direction of first dovetail body 6 and the activity of second dovetail body 10 is all to be close to the locating body 8, continues to rotate the regulation pole 9 for movable body 7 and locating body 8 contradict in the both sides of first ear 15, and wherein movable body 7 need not to laminate first ear 15 completely with locating body 8, but also needs the both sides of first ear 15 to laminate respectively on movable body 7 and locating body 8. When the turning is carried out, the direction of the positioning body 8 facing the first lug part 15 is the rotating direction of the driving disc 4;

in the rotating process, the supporting cylinder 1 keeps the position of the supporting cylinder fixed, lubricating oil is brushed on the end parts of the positioning ejector pins 3 and the ejector pins, the positioning ejector pins 3 can be driven by the steering knuckle to rotate, but the driving disc 4 cannot drive the supporting cylinder 1 or the positioning ejector pins 3 to rotate, and the rotating ejector pin positioning device has the advantage of reducing the load and energy consumption of the driving disc 4. Wherein the connecting portion 3a is tapered or truncated cone-shaped, so that when the positioning thimble 3 is collided by the knuckle, the positional stability of the positioning thimble 3 can be ensured without slipping out of the support hole 2.

Meanwhile, the structure for holding the supporting cylinder 1 and rotating the driving disc 4 is not limited too much, for example, the supporting cylinder 1 is welded on the frame, and the driving disc 4 is rotatably connected to the outer wall of the supporting cylinder 1 through a bearing or other conventional structures, or other conventional structures can be realized.

In the process of turning, the positioning body 8 is the main power for driving the steering knuckle to rotate, and the positioning body 8 is welded on the driving disc 4, so that the positioning body 8 and the driving disc 4 have stronger structural strength, and the movable body 7 only has a limiting effect on the first lug part 15, so that the requirement on the structural strength is lower, the positioning body 8 is welded, and the movable body 7 is movably connected through the first dovetail body 6, so that the best comprehensive effect can be achieved.

During the rotation of the driving disc 4, one side of the driving disc 4 has larger mass due to the positioning body 8, the movable body 7, the first dovetail body 6 and the second dovetail body 10, and the action of balancing the driving disc 4 can be realized to a certain extent by opening the movable dovetail groove 5; meanwhile, the balancing weight is attached, so that the bearing balance of the driving disc 4 can be well realized, the centrifugal effect of the driving disc 4 generated in the rotating process is reduced, and the structure for supporting and driving the driving disc 4 is protected.

The end of the adjusting rod 9 is provided with a nut, so that the adjusting rod 9 can be conveniently rotated, and meanwhile, one side of the movable dovetail groove 5 penetrates through the side part of the driving disk 4, so that the movable dovetail groove 5 provides a space for rotating the adjusting rod 9 in actual operation, and the practicability is strong.

When a turning is finished, the adjusting rod 9 is rotated reversely to drive the first dovetail body 6, the second dovetail body 10 and the movable body 7 to move towards the direction far away from the positioning body 8, and when the process is carried out, the clamping piece 11 is clamped into the clamping groove 12. After rotating a certain distance, the movable body 7 releases the first ear 15, and at the moment, the steering knuckle can be directly taken down from the positioning thimble 3 only after the slide carriage box (after the thimble is separated from the outer journal 19) is moved backwards.

Wherein, adjust pole 9 and drive joint spare 11 and enter into joint groove 12 back, joint spare 11 can play a spacing effect to location portion 3b to prevent that location thimble 3 from droing out from supporting hole 2, when next car adds man-hour, can push supporting hole 2 with location thimble 3 restabiltiy through carriage box, thimble and knuckle, consequently can prevent to fix a position thimble 3 and deviate from supporting hole 2 at this in-process (unless need when taking off location thimble 3, do not put the knuckle and only rotate regulation pole 9 can). Moreover, because the end of the supporting cylinder 1 and the end of the connecting part 3a are both located in the inner cavity of the center of the driving disk 4, when the clamping piece 11 is separated from the clamping groove 12, the clamping piece 11 will not rub against the supporting cylinder 1 and the positioning thimble 3 in the rotating process of the driving disk 4, so that the clamping piece 11 and the positioning thimble 3 are prevented from being worn, and the noise is prevented from being generated. In the whole processing process, the clamping piece 11 is limited by the counterweight piece 13 and can only be attached to the surface of the driving disc 4 to move, so that the position stability of the clamping piece can be ensured.

The first dovetail body 6 and the second dovetail body 10 are both driven by the adjusting rod 9, and the advantages are that:

during the processing, the movable body 7 and the positioning body 8 are abutted against two sides of the first lug part 15, and the positioning thimble 3 is limited by the flange plate 14 on the steering knuckle, so that the position of the positioning thimble is stable;

after the knuckle is taken off, although the positioning thimble 3 is not limited by the flange 14, the clamping piece 11 can be clamped into the clamping groove 12 to limit the positioning thimble 3 and prevent the positioning thimble 3 from being pulled out of the supporting hole 2.

Wherein, the conventional connection mode between location thimble and the support section of thick bamboo at present is: the outer wall of the opening end of the supporting cylinder is welded with a nut, then the outer wall of the positioning thimble is provided with an external thread matched with the nut, and the positioning thimble is connected with the nut through threads. Although the positioning thimble and the supporting cylinder can be connected, if the rotation direction of the steering knuckle is the direction in which the positioning thimble and the supporting cylinder are more loosely connected, the steering knuckle cannot become loose (namely the length cannot be lengthened) due to the limit of the steering knuckle, so that the trend acting force of the steering knuckle driving the positioning thimble to rotate needs to be borne by the thread between the positioning thimble and the nut, and the thread is damaged in the long term and the subsequent use is influenced. If the rotating direction of the steering knuckle is the direction that the positioning thimble is connected with the supporting cylinder more tightly, or the positioning thimble moves after rotating, the steering knuckle can not be supported stably; or the location thimble also is the same with this application, has adopted the structure of round platform shape and can't the displacement, but even its can't the displacement, the screw thread between location thimble and the nut still need bear the knuckle drive location ejector pin pivoted trend power, still has certain damage to the screw thread of location thimble and nut.

It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.