Method for ensuring coaxiality of a two-part cylindrical pin connected in rotation

Abstract

The application relates to the technical field of machining, in particular to a coaxiality guarantee method for a two-section cylindrical pin in rotary connection, which assembles a cylindrical pin front section and a cylindrical pin rear section into a cylindrical pin semi-finished product in a rotary connection mode, and then processes under centerless grinding in a state that the front section and the rear section are located on the same straight line; wherein the outer cylinders of the cylindrical pin front section and the cylindrical pin rear section before centerless grinding are all reserved with machining allowances, and the outer diameters of the cylindrical pin front section and the cylindrical pin rear section reserved with the machining allowances are the same. The scheme is used to solve the problem that the coaxiality of the two-section cylindrical pin in rotary connection is difficult to guarantee.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a method for ensuring the coaxiality of a two-section cylindrical pin with a rotating connection. Background Technology

[0002] A cylindrical pin structure formed by connecting two equal-diameter cylinders using a movable riveting method (such as...) Figure 1 As shown, Figure 1 The image shows two states of a cylindrical pin. These two cylindrical sections with equal diameters at the front and rear are required to rotate to a horizontal position to form a straight line, and also to rotate 90 degrees. When rotating to the horizontal position, the coaxiality requirement is very high, for example, the coaxiality requirement is Φ0.02mm. The conventional processing method is to first process the front section and the rear section of the cylindrical pin separately, and then assemble the front and rear sections together by a movable riveting method. The coaxiality of this riveted cylindrical pin relies on the processing accuracy of the front and rear sections of the cylindrical pin. However, in actual production, this method has a very low pass rate due to the very high coaxiality requirement, with a pass rate of about 10%. Summary of the Invention

[0003] The present invention aims to provide a method for ensuring the coaxiality of a two-section cylindrical pin in a rotary connection, so as to solve the problem that it is difficult to ensure the coaxiality of the cylindrical pin in the front and rear two-section structure under the current rotary connection.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for ensuring the coaxiality of a two-section cylindrical pin in a rotatable connection includes the following steps:

[0006] The front and rear sections of the cylindrical pin are assembled into a semi-finished cylindrical pin by a rotating connection, and then the front and rear sections are machined under centerless grinding with the front and rear sections in the same straight line.

[0007] In particular, both the front and rear sections of the cylindrical pin have pre-reserved machining allowances before centerless grinding, and the outer diameters of the pre-reserved cylindrical pin sections and the rear sections are the same.

[0008] The principle and advantages of this solution are as follows: By leaving machining allowance for the front and rear sections of the cylindrical pin before centerless grinding, the front and rear sections of the cylindrical pin are ground as a whole during centerless grinding. The machining allowance is removed during the grinding process. After grinding, the front and rear sections of the cylindrical pin not only have the same outer diameter, but also ensure high coaxiality due to synchronous centerless grinding. The coaxiality can meet the requirement of Φ0.02mm, and the pass rate is greatly improved under this method.

[0009] In conventional centerless grinding, the workpiece being ground is often a single part (a shaft-like part, or a part formed by fixed connections). The end of the part is placed between the grinding wheel and the guide wheel of the centerless grinder. At different speeds of the grinding wheel and the guide wheel, the workpiece is ground while simultaneously being axially moved on a support plate. The workpiece enters from one axial side between the grinding wheel and the guide wheel, and is then processed from the other axial side before being completely removed. Currently, centerless grinding is generally only used for machining single-piece parts. When machining parts with two rotating connections, the relative rotation between the two sections can easily damage the machine tool. Therefore, centerless grinding has not yet been used to maintain coaxiality in two-section rotating structures.

[0010] This solution breaks away from the conventional understanding that centerless grinding only grinds the entire outer diameter of a part. Because the outer diameters of the front and rear sections of the cylindrical pin are the same before grinding, they are easily kept in a straight line before and during centerless grinding. Therefore, during grinding, both the front and rear sections of the cylindrical pin are ground simultaneously, preventing damage to the centerless grinder due to relative rotation between the front and rear sections. Furthermore, by simultaneously grinding both the front and rear sections of the cylindrical pin, the high coaxiality requirement of the two sections is ensured after the machining allowance is ground. Verification has shown that the coaxiality qualification rate is significantly improved under this solution.

[0011] Furthermore, this solution eliminates the need for high-precision machining control of the front and rear sections required in existing technologies, and also avoids imposing higher assembly requirements to ensure coaxiality. It only requires sufficient machining allowance and centerless grinding of the front and rear sections of the cylindrical pin while maintaining a straight line. The entire operation is simple and convenient. It not only solves the industry's problem of difficulty in ensuring coaxiality for such products, but also improves processing efficiency and reduces processing costs.

[0012] Preferably, as an improvement, during centerless grinding, the outer cylinder of both the front and rear sections of the cylindrical pin needs to be ground to ensure the coaxiality requirement after centerless grinding.

[0013] Preferably, as an improvement, before starting centerless grinding, the workpiece is placed on the support plate between the grinding wheel and the guide wheel of the centerless grinder in a straight line, with both the front and rear sections of the cylindrical pin located between the grinding wheel and the guide wheel. This ensures that the front and rear sections of the cylindrical pin remain synchronized during grinding, preventing damage to the centerless grinder and guaranteeing coaxiality after processing.

[0014] Preferably, as an improvement, the rear section of the cylindrical pin has a head with a diameter larger than the outer cylinder. During centerless grinding, the head abuts against the end face of the support plate to ensure that the head is not ground. This also facilitates placing the front and rear sections of the cylindrical pin on the support plate in a straight line during centerless grinding. Furthermore, the presence of the cylindrical pin head prevents the entire two-section structure from having only one section positioned between the grinding wheel and the guide wheel (if only the front or rear section is positioned between the grinding wheel and the guide wheel, the front and rear sections will rotate relative to each other as the workpiece rotates, resulting in localized impacts of the workpiece against the centerless grinder under centrifugal force). This ensures that the front and rear sections of the cylindrical pin are always processed synchronously throughout the centerless grinding process, preventing damage to the centerless grinder and guaranteeing coaxiality requirements and a very high machining yield.

[0015] Preferably, as an improvement, the front and rear sections of the cylindrical pin are processed before the semi-finished cylindrical pin is assembled. The processing requirements are: except for the machining allowance reserved for the outer cylinder, all other dimensions are processed to meet the requirements.

[0016] Preferably, as an improvement, the front and / or rear sections of the cylindrical pin in the semi-finished cylindrical pin are processed after the material has been heat-treated.

[0017] Preferably, as an improvement, the front and rear sections of the cylindrical pin in the semi-finished product are connected by a movable riveting method. Attached Figure Description

[0018] Figure 1 This is a front view schematic diagram of the two-section cylindrical pin to be processed in this invention (the diagram shows two states of the cylindrical pin: one on the same straight line and the other rotated 90°).

[0019] Figure 2 These are the front view and top view of the cylindrical pin front section obtained in step S1 of the present invention.

[0020] Figure 3 These are the front view and top view of the rear section of the cylindrical pin obtained in step S1 of the present invention (wherein the top view contains a partial section).

[0021] Figure 4 This is a front view of the cylindrical pin semi-finished product obtained in step S2 of the present invention.

[0022] Figure 5 This is a front view of the cylindrical pin product obtained by the present invention.

[0023] Figure 6 This is a schematic diagram of the structure of the present invention when the head of the cylindrical pin abuts against the support plate of the centerless grinder (this view is a axial cross-section diagram during centerless grinding, in which the cylindrical pin is not cross-sectioned).

[0024] Figure 7 for Figure 6 A schematic diagram of the left section (the section is cut at the front of the cylindrical pin). Detailed Implementation

[0025] The following detailed description illustrates the specific implementation method:

[0026] The reference numerals in the accompanying drawings include: 1. front section of cylindrical pin; 2. rivet; 3. rear section of cylindrical pin; 4. grinding wheel; 5. support plate; 6. guide wheel; 31. head of cylindrical pin.

[0027] The basic implementation examples are as follows: Figures 1 to 7 As shown.

[0028] A method for ensuring the coaxiality of a two-section cylindrical pin with a rotating connection, used to process a two-section cylindrical pin connected by a movable hinge, specifically includes the following steps:

[0029] S1. The front section 1 and the rear section 3 of the cylindrical pin after heat treatment are processed respectively. After processing, the outer cylinder of the front section 1 and the rear section 3 of the cylindrical pin is reserved with a machining allowance. The outer diameter of the front section 1 and the rear section of the cylindrical pin is the same after the machining allowance is reserved. After processing, except for the machining allowance of the outer cylinder, the other dimensions are all qualified.

[0030] In step S1, to process as follows Figure 1 Taking the two-section cylindrical pin shown as an example, both the front section 1 and the rear section of the cylindrical pin have a machining allowance of 0.3mm, and all other dimensions are qualified. The structure of the front section 1 of the cylindrical pin in this step is as follows: Figure 2 As shown, the rear section 3 of the cylindrical pin is as follows Figure 3 As shown.

[0031] S2. Assemble the front section 1 and rear section 3 of the cylindrical pin using rivets 2 via a movable riveting method to obtain a semi-finished cylindrical pin. A specific example is shown below. Figure 4 As shown.

[0032] S3. Place the semi-finished cylindrical pin on the support plate 5 between the grinding wheel 4 and the guide wheel 6 of the centerless grinder, keeping it in a straight line. Both the front section 1 and the rear section 3 of the cylindrical pin are located between the grinding wheel 4 and the guide wheel 6. There is a gap between the head of the rear section 3 of the cylindrical pin and the end face of the support plate 5. Then start the centerless grinder to perform centerless grinding.

[0033] After centerless grinding, the result is as follows Figure 5 The aforementioned two-section cylindrical pin finished product.

[0034] In step S3, the outer cylinders of the front section 1 and the rear section 3 of the cylindrical pin need to be ground to ensure that the coaxiality after processing meets the requirements.

[0035] In step S3, during centerless grinding, the grinding wheel 4 and the guide wheel 6 gradually approach each other, gradually grinding away the machining allowance of the front section 1 and the rear section 3 of the cylindrical pin. At the same time, the entire cylindrical pin moves axially and rotates under the processing of the centerless grinder until the end face of the head 31 of the rear section 3 of the cylindrical pin abuts against the end face of the support plate 5. After abutting, the entire cylindrical pin only rotates and does not move axially until the outer cylinders of the front section 1 and the rear section 3 of the cylindrical pin are completely ground, and then the centerless grinding stops, completing the processing of the workpiece.

[0036] This embodiment uses a simple processing method to reduce the precision control requirements of the two-stage cylindrical pin process, reduce processing costs, improve processing efficiency, and ensure the coaxiality requirements after processing by using centerless grinding.

[0037] This embodiment breaks with the conventional understanding that centerless grinding only grinds the entire outer diameter of a part. In this embodiment, because the outer diameters of the front section 1 and the rear section 3 of the cylindrical pin are the same before grinding, they can easily be kept in the same straight line before centerless grinding and continue to be kept in the same straight line during the centerless grinding process. Therefore, during the grinding process, both the front section 1 and the rear section 3 of the cylindrical pin are ground simultaneously, avoiding the situation where the front and rear sections of the cylindrical pin rotate relative to each other and damage the centerless grinding machine. At the same time, the simultaneous grinding of the front section 1 and the rear section 3 of the cylindrical pin by centerless grinding ensures the high requirement of coaxiality between the front and rear sections of the cylindrical pin after the machining allowance is ground. It has been verified that the coaxiality qualification rate under this embodiment is not less than 98%.

[0038] Furthermore, because the head 31 of the cylindrical pin rests on the support plate 5 at the last moment of centerless grinding, the outer cylinder of the front section 1 and the rear section 3 of the cylindrical pin is only processed by the centerless grinder under rotation. The surface quality after grinding is high, thus improving the surface roughness of the cylindrical pin.

[0039] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for ensuring the coaxiality of a two-section cylindrical pin in a rotatable connection, characterized in that: The front and rear sections of the cylindrical pin are assembled into a semi-finished cylindrical pin by a rotating connection, and then the front and rear sections are machined under centerless grinding with the front and rear sections in the same straight line. In particular, the outer cylinders of both the front and rear sections of the cylindrical pin before centerless grinding are reserved with machining allowance, and the outer diameters of the front and rear sections of the cylindrical pin with reserved machining allowance are the same. Before starting centerless grinding, place the workpiece on the support plate between the grinding wheel and the guide wheel of the centerless grinder in a straight line, with both the front and rear sections of the cylindrical pin located between the grinding wheel and the guide wheel. In centerless grinding, the outer cylinder of both the front and rear sections of the cylindrical pin needs to be ground completely. The cylindrical pin has a head with a diameter larger than the outer cylinder at the rear end. When the cylindrical pin is centerlessly ground, the head is used to abut against the end face of the support plate.

2. The method for ensuring the coaxiality of a two-section cylindrical pin in a rotary connection according to claim 1, characterized in that: Before assembling the semi-finished cylindrical pins, the front and rear sections of the cylindrical pins are processed. The processing requirements are: except for the machining allowance reserved for the outer cylinder, all other dimensions are processed to meet the requirements.

3. The method for ensuring the coaxiality of a two-section cylindrical pin in a rotary connection according to claim 2, characterized in that: The front and / or rear sections of the cylindrical pin in the semi-finished cylindrical pin are processed after the material has been heat-treated.

4. A method for ensuring the coaxiality of a two-section cylindrical pin in a rotary connection according to any one of claims 1-3, characterized in that: The front and rear sections of the cylindrical pin in the semi-finished product are connected by a movable riveting method.

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