Automatic clamping device for lower center of hollow camshaft

Abstract

The utility model discloses an automatic clamping device for a lower tip of a hollow camshaft, which belongs to the technical field of camshaft processing and comprises a base, a tip body arranged on the base, a cylindrical accommodating cavity arranged in the tip body, a lower tip arranged in the accommodating cavity in an up-down sliding manner and arranged in the accommodating cavity, and an upper end of the lower tip extending to the upper part of the accommodating cavity. A supporting spring is arranged between the lower tip and the bottom of the containing cavity, a vertical long hole is formed in the tip body on the lower portion of the containing cavity, a transverse pin hole is formed in the lower portion of the lower tip and extends into the long hole in the lower portion of the containing cavity, and a fixing pin is transversely connected into the transverse pin hole in a penetrating mode. According to the utility model, the center is precisely matched with the center hole of the camshaft, and the clamping force and the clamping precision are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of camshaft processing, in particular to a top automatic clamping device. Background Technique

[0002] The valve camshaft is an important driving and controlling component of the engine, which has a great influence on the reliability, service efficiency and service life of the engine. When the valve camshaft works, it precisely opens and closes the intake and exhaust valves according to the valve timing. Relative sliding friction occurs between the cam and the push rod, and the cam profile is in the boundary lubrication or mixed lubrication state. Since the thickness of the formed lubricating film is thin and uneven, failure forms such as abrasion, pitting and rapid wear often occur on the cam surface. In order to ensure that the service performance, working life and emission index of the engine meet the regulations, in addition to requiring the valve camshaft to have sufficient toughness and stiffness, it should also have good anti-contact fatigue ability, anti-abrasion property and wear resistance. With the continuous improvement of the requirements for engine weight reduction and power enhancement, more and more valve camshafts adopt a hollow structure form.

[0003] Medium carbon steel is generally selected for the valve camshaft, and induction hardening is carried out on the shaft diameter and the cam through an induction coil to improve the surface hardness, wear resistance and contact fatigue performance. In order to ensure the performance of the shaft diameter and the cam of the camshaft during the heat treatment strengthening process, higher requirements are put forward for the clamping and positioning device. Generally, the method of clamping the center center holes at both ends of the camshaft by the upper and lower fixed tops is adopted to clamp and position the camshaft.

[0004] When using a fixed top to clamp and position the center center holes at both ends of the camshaft, there are mainly disadvantages such as inaccurate clamping and positioning, poor wear resistance and poor versatility. Displacement will occur during the rotation of the camshaft, which cannot meet the requirements of the heat treatment strengthening control accuracy. Moreover, it cannot meet the clamping requirements for the hollow structure form of the camshaft. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide an automatic clamping device for the lower top of a hollow camshaft, so that the top is precisely matched with the center hole of the camshaft, and the clamping force and clamping accuracy are improved.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] An automatic clamping device for the lower top of a hollow camshaft, including a base, a top body is arranged on the base, a cylindrical receiving cavity is arranged in the top body, a lower top that slides up and down in the receiving cavity is arranged in the receiving cavity, the upper end of the lower top extends to the upper part of the receiving cavity, a support spring is arranged between the lower top and the bottom of the receiving cavity, a vertical long hole is opened on the top body at the lower part of the receiving cavity, a transverse pin hole is arranged at the lower part of the lower top and extends into the vertical long hole at the lower part of the receiving cavity, and a fixing pin is horizontally inserted into the transverse pin hole.

[0008] A further improvement of the technical solution of the present utility model lies in that: a washer with a central opening is connected to the upper end surface of the top body, the upper end of the lower top extends upward from the central opening of the washer, and a plurality of positioning pin holes are provided on the circumferential surface of the upper end surface of the washer, and a positioning pin is provided in one of the positioning pin holes.

[0009] A further improvement of the technical solution of the present utility model lies in that: screw holes are provided on the upper end surface of the top body, and U-shaped fixing grooves with openings facing outward are provided on the circumferential surface of the upper surface of the washer.

[0010] A further improvement of the technical solution of the present utility model lies in that: a plurality of transverse pin holes are provided at intervals along the height direction at the lower part of the lower top.

[0011] A further improvement of the technical solution of the present utility model lies in that: a circle of connection holes is provided on the base.

[0012] Due to the adoption of the above technical solution, the technical progress achieved by the present utility model is:

[0013] Aiming at the shortcomings of the existing technology and the actual structure of the hollow camshaft, the lower top of the present invention adopts a conical top and a spring lower support automatic clamping method, so that the top is precisely matched with the central hole of the camshaft, improving the clamping force and clamping accuracy, ensuring the gap accuracy during the intermediate frequency quenching heating of the camshaft, and thus ensuring the intermediate frequency heat treatment performance of the hollow camshaft.

[0014] The setting of the long hole provides sufficient installation space and up-and-down sliding stroke for the lower top; a plurality of positioning pin holes are provided on the washer, and the positioning pin is selected and installed according to the actual situation to cooperate with the camshaft for positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0016] Figure 1 is an exploded view of the present utility model;

[0017] Among them, 1. Base, 2. Top body, 3. Accommodation cavity, 4. Lower top, 5. Support spring, 6. Long hole, 7. Fixed pin, 8. Washer, 9. Positioning pin hole, 10. Positioning pin, 11. Screw hole, 12. U-shaped fixing groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will further describe the present utility model in detail with reference to the embodiments:

[0019] An automatic clamping device for the lower tip of a hollow camshaft, as Figure 1 shown, includes a base 1. A tip body 2 is provided on the base 1, and the base 1 and the tip body 2 can be integral. The base 1 includes a cylinder and a flange at the upper end. A circle of connection holes is provided on the flange for fixing the automatic clamping device of the lower tip.

[0020] The tip body 2 includes two coaxial cylindrical structures with different diameters up and down. A cylindrical receiving cavity 3 is provided inside the cylindrical structure at the upper part of the tip body 2. A vertical long hole 6 is opened on the cylindrical structure at the lower part of the tip body 2, and the long hole 6 penetrates from one side of the tip body 2 to the other side. A lower tip 4 is provided in the receiving cavity 3. The lower tip 4 includes two coaxial cylinders with different diameters up and down and a conical tip at the uppermost end. The lower tip 4 slides up and down in the receiving cavity 3. The upper end tip of the lower tip 4 extends to the upper part of the receiving cavity 3. The diameter of the conical part at the head of the lower tip 4 is slightly larger than that of the cylindrical part to form a flange. A support spring 5 is sleeved outside the lower tip 4. The upper end of the support spring 5 abuts against the lower part of the flange, and the lower end abuts against the bottom surface inside the receiving cavity 3. The smaller-diameter end of the lower part of the lower tip 4 extends into the long hole 6 at the lower part of the receiving cavity 3, and a transverse pin hole is provided in the smaller-diameter part of the lower part of the lower tip 4. A fixing pin 7 is horizontally inserted in the transverse pin hole, and the fixing pin 7 lies across the long hole 6.

[0021] Further preferably, a washer 8 is connected to the upper end surface of the tip body 2 by bolts. A screw hole 11 is provided on the upper end surface of the tip body 2. An outward-opening U-shaped fixing groove 12 is provided on the circumference of the upper surface of the washer 8. Bolts are installed at the U-shaped fixing groove 12 to realize the fastening connection between the washer 8 and the tip body 2. A hole is opened in the middle of the washer 8. The conical head part at the upper end of the lower tip 4 extends upward from the hole in the middle of the washer 8. A plurality of positioning pin holes 9 are provided on the circumference of the upper end surface of the washer 8. A positioning pin 10 is provided in one of the positioning pin holes 9 for positioning with the camshaft. Preferably, the washer 8 can be made of martensitic stainless steel and quenched as a whole to reach 50-55HRC, or other wear-resistant materials can be selected, so as to play a wear-resistant role, avoid heat treatment of the entire tip body 2 or select special materials, and save costs.

[0022] Further preferably, a plurality of transverse pin holes are provided at intervals along the height direction at the lower part of the lower tip 4, and different transverse pin holes are selected according to the actual situation to insert the fixing pin 7.

[0023] In view of the shortcomings of the prior art and the actual structure of the hollow camshaft, the present invention uses a conical tip for the lower tip. The tip can be made of martensitic stainless steel and its surface hardness can be improved after heat treatment and quenching, so as to improve its wear resistance and service life. And an automatic clamping method with spring lower support is adopted, so that the tip is precisely matched with the central hole of the camshaft, the clamping force and clamping accuracy are improved, and the gap accuracy during the intermediate frequency quenching heating of the camshaft is ensured, thereby ensuring the intermediate frequency heat treatment performance of the hollow camshaft.

[0024] The embodiments described above are only descriptions of the preferred embodiments of the present utility model, and do not limit the scope of the present utility model. Without departing from the design spirit of the present utility model, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present utility model shall fall within the protection scope determined by the claims of the present utility model.

Claims

1. An automatic clamping device for the lower tip of a hollow camshaft, comprising a base (1), characterized in that: A center body (2) is provided on a base (1). A cylindrical receiving cavity (3) is provided inside the center body (2). A lower center (4) that slides up and down in the receiving cavity (3) is provided inside the receiving cavity (3). The upper end of the lower center (4) extends to the upper part of the receiving cavity (3). A support spring (5) is provided between the lower center (4) and the bottom of the receiving cavity (3). A vertical long hole (6) is formed in the center body (2) at the lower part of the receiving cavity (3). A transverse pin hole is provided at the lower part of the lower center (4) and extends into the long hole (6) at the lower part of the receiving cavity (3). A fixing pin (7) is horizontally inserted and fixed in the transverse pin hole.

2. The automatic clamping device for the lower center point of a hollow camshaft according to claim 1, characterized in that: A washer (8) with a central opening is connected to the upper end face of the center body (2). The upper end of the lower center (4) extends upward from the central opening of the washer (8). A plurality of positioning pin holes (9) are provided on the circumference of the upper end face of the washer (8). A positioning pin (10) is provided in one of the positioning pin holes (9).

3. An automatic clamping device for the lower center point of a hollow camshaft according to claim 2, characterized in that: A screw hole (11) is provided on the upper end face of the center body (2). An outward-opening U-shaped fixing groove (12) is provided on the circumference of the upper surface of the washer (8).

4. An automatic clamping device for the lower center point of a hollow camshaft according to claim 1, characterized in that: A plurality of transverse pin holes are provided at intervals along the height direction at the lower part of the lower center (4).

5. An automatic clamping device for the lower center point of a hollow camshaft according to claim 1, characterized in that: A circle of connection holes is provided on the base (1).

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