Method for guaranteeing coaxiality of rotationally connected two-section cylindrical pin

Abstract

The invention relates to the technical field of machining, and particularly discloses a coaxiality guaranteeing method for a rotationally-connected two-section type cylindrical pin, which comprises the following steps: assembling a cylindrical pin front section and a cylindrical pin rear section into a cylindrical pin semi-finished product in a rotationally-connected manner, and then machining under centerless grinding in a state that the front section and the rear section are positioned on the same straight line; wherein machining allowances are reserved on outer cylinders of the cylindrical pin front section and the cylindrical pin rear section before centerless grinding, and the outer diameters of the cylindrical pin front section and the cylindrical pin rear section with the reserved machining allowances are the same. The scheme is used for solving the problem that the coaxiality of a cylindrical pin of a front-back two-section structure under rotary connection at present is difficult to guarantee.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing, and in particular to a method for ensuring the coaxiality of a two-section cylindrical pin connected in rotation. Background Art

[0002] In the cylindrical pin structure formed by the front and rear sections of equal diameter cylinders connected by active riveting (such as Figure 1 As shown, Figure 1 The two states of the cylindrical pin are shown in the figure). The two front and rear equal-diameter cylindrical sections are required to be able to rotate to a horizontal position to form a straight line and to rotate 90°. When rotating to a 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 section and the rear section together through active riveting. The coaxiality of this riveted cylindrical pin is maintained by the processing accuracy of the front section and the rear section of the cylindrical pin. However, in actual production, this type of method has a very low pass rate due to the very high coaxiality requirement, and the pass rate is about 10%. Summary of the invention

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

[0004] In order to achieve the above object, the present invention adopts the following technical scheme: A method for ensuring the coaxiality of a two-section cylindrical pin connected in rotation comprises the following steps: The front section and the rear section of the cylindrical pin are assembled into a cylindrical pin semi-finished product by means of rotational connection, and then processed by centerless grinding in a state where the front section and the rear section are located in the same straight line; Among them, the outer cylinders of the front section and the rear section of the cylindrical pin before centerless grinding are both reserved with machining allowances, and the outer diameters of the front section and the rear section of the cylindrical pin with reserved machining allowances are the same.

[0005] The principle and advantage of this solution are: by leaving a processing allowance for the front section and the rear section of the cylindrical pin before centerless grinding, the front section and the rear section of the cylindrical pin are ground as a whole during centerless grinding, and the remaining processing allowance is ground away during the grinding process. After grinding, the front section and the rear section of the cylindrical pin not only have the same outer diameter, but also have high coaxiality requirements due to the simultaneous centerless grinding. The coaxiality can meet the requirement of Φ0.02mm, and the qualified rate is greatly improved under this method.

[0006] In conventional centerless grinding, the workpiece being ground is often a whole part (a shaft-like part, or a part that is fixedly connected to form a whole). 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 part is ground while the workpiece placed on the pallet is axially pushed. The workpiece enters between the grinding wheel and the guide wheel from one axial side, and then is processed from the other axial side and the part is completely sent out. In the current conventional understanding, centerless grinding is only used for processing whole parts. When processing parts with front and rear sections connected in rotation, the front and rear sections are easily damaged due to relative rotation, so centerless grinding has not yet been used to maintain the coaxiality of a two-section structure with a rotation connection.

[0007] This solution breaks the conventional understanding that centerless grinding only grinds the entire external cylinder of the entire part. Because the outer diameters of the front section and the rear section of the cylindrical pin are the same before grinding, it is easy to keep them in the same straight line before centerless grinding and continue to keep them in the same straight line during the centerless grinding process. Therefore, during the grinding process, the front section and the rear section of the cylindrical pin are ground at the same time, and there will be no relative rotation of the front and rear sections to damage the centerless grinder. At the same time, the front section and the rear section of the cylindrical pin are ground simultaneously by centerless grinding, ensuring the high requirement of coaxiality of the front and rear sections of the cylindrical pin after the machining allowance is ground. It has been verified that the coaxiality pass rate under this solution is greatly improved.

[0008] In addition, this solution does not require high-precision processing control of the front and rear sections in the prior art, nor does it require higher requirements for assembly due to coaxiality requirements. It only requires leaving sufficient processing allowance and ensuring that the front and rear sections of the cylindrical pin are centerlessly ground while maintaining a straight line. The entire operation method is simple and convenient. While solving the industry's problem of difficulty in ensuring coaxiality for such products, it also improves processing efficiency and reduces processing costs.

[0009] Preferably, as an improvement, during centerless grinding, the outer cylinders of the front section and the rear section of the cylindrical pin need to be completely ground to ensure the coaxiality requirement after centerless grinding.

[0010] Preferably, as an improvement, before starting the centerless grinding, the workpiece is placed on a support plate between the grinding wheel and the guide wheel of the centerless grinder in a straight line, and the front section and the rear section of the cylindrical pin are both located between the grinding wheel and the guide wheel, thereby ensuring that the front section and the rear section of the cylindrical pin always remain synchronized during the grinding process, ensuring that the centerless grinder will not be damaged and ensuring the coaxiality after processing.

[0011] Preferably, as an improvement, the rear section of the cylindrical pin has a head with a diameter larger than that of the outer cylinder. When the cylindrical pin is subjected to centerless grinding, the head is used to abut against the end face of the support plate to ensure that the head will not be ground. At the same time, when centerless grinding is performed, the front section of the cylindrical pin and the rear section of the cylindrical pin are placed on the support plate and are in a straight line. In addition, due to the presence of the head of the cylindrical pin, the cylindrical pin of the entire two-section structure will not have a situation where only one section is located between the grinding wheel and the guide wheel (if only the front section or the rear section is between the grinding wheel and the guide wheel, it will cause the front and rear sections to rotate relative to each other when the workpiece rotates, so that the workpiece partially hits the centerless grinder under the centrifugal force of the rotation), ensuring that the front section of the cylindrical pin and the rear section of the cylindrical pin are always processed synchronously during the entire process of centerless grinding, ensuring that the centerless grinder will not be damaged, while ensuring the coaxiality requirements and a very high processing pass rate.

[0012] Preferably, as an improvement, the front section and the rear section of the cylindrical pin are processed before the cylindrical pin semi-finished product is assembled, and the processing requirements are: except for the reserved processing allowance of the outer cylinder, the other dimensions are processed to qualified standards.

[0013] Preferably, as an improvement, the cylindrical pin front section and / or the cylindrical pin rear section in the cylindrical pin semi-finished product are processed after the material is heat treated.

[0014] Preferably, as an improvement, the cylindrical pin front section and the cylindrical pin rear section of the cylindrical pin semi-finished product are connected by active riveting. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic front view of a two-section cylindrical pin to be processed in the present invention (the figure shows two states of the cylindrical pin being in the same straight line and rotated 90 degrees).

[0016] Figure 2 The front view and top view of the front section of the cylindrical pin obtained in step S1 of the present invention.

[0017] Figure 3 The front view and top view (wherein the top view has a partial section) of the rear section of the cylindrical pin obtained in step S1 of the present invention.

[0018] Figure 4 This is a front view of the semi-finished cylindrical pin obtained in step S2 of the present invention.

[0019] Figure 5 This is a front view of the finished cylindrical pin obtained by processing according to the present invention.

[0020] Figure 6 It is a schematic diagram of the structure of the present invention when the head of the cylindrical pin abuts against the support plate on the centerless grinding machine (this view is an axial section diagram during centerless grinding, in which the cylindrical pin is not sectioned).

[0021] Figure 7 for Figure 6 Left section schematic diagram (the section position is at the front section of the cylindrical pin). DETAILED DESCRIPTION

[0022] The following is further described in detail through specific implementation methods: The reference numerals in the drawings of the specification include: a front section 1 of a cylindrical pin, a rivet 2, a rear section 3 of a cylindrical pin, a grinding wheel 4, a support plate 5, a guide wheel 6, and a head 31 of a cylindrical pin.

[0023] The embodiment is basically as shown in the attached Figures 1 to 7 shown.

[0024] A method for ensuring the coaxiality of a two-section cylindrical pin connected in a rotating manner is used for processing a two-section cylindrical pin connected in a movable hinge manner, and specifically comprises the following steps: S1. The cylindrical pin front section 1 and the cylindrical pin rear section 3 are processed respectively after the heat treatment of the material is completed. After processing, the outer cylinders of the cylindrical pin front section 1 and the cylindrical pin rear section 3 are reserved with processing allowances, and the outer diameters of the cylindrical pin front section 1 and the rear section are the same after the reserved processing allowances. After processing, except for the reserved processing allowances of the outer cylinders, the other dimensions are all qualified.

[0025] In the S1 step, the processing Figure 1 Taking the two-section cylindrical pin shown in the figure as an example, a machining allowance of 0.3 mm is reserved for the front section 1 and the rear section of the cylindrical pin, and the 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 shown in Figure 3 shown.

[0026] S2, assemble the cylindrical pin front section 1 and the cylindrical pin rear section 3 by active riveting through the rivet 2 to obtain a cylindrical pin semi-finished product. Figure 4 shown.

[0027] S3. Place the cylindrical pin semi-finished product on the support plate 5 between the grinding wheel 4 and the guide wheel 6 of the centerless grinder while maintaining a straight line, with the cylindrical pin front section 1 and the cylindrical pin rear section 3 both located between the grinding wheel 4 and the guide wheel 6, and there is a gap between the head of the cylindrical pin rear section 3 and the end face of the support plate 5, and then start the centerless grinder for centerless grinding.

[0028] After centerless grinding, Figure 5 The two-section cylindrical pin finished product.

[0029] In step S3, the outer cylinders of the cylindrical pin front section 1 and the cylindrical pin rear section 3 need to be completely ground to ensure that the coaxiality after processing meets the requirements.

[0030] In step S3, during centerless grinding, the grinding wheel 4 and the guide wheel 6 gradually approach each other and gradually grind off the machining allowances of the cylindrical pin front section 1 and the cylindrical pin rear section 3. At the same time, the cylindrical pin as a whole is also moved axially and rotated under the processing of the centerless grinder until the end face of the head 31 of the cylindrical pin rear section 3 abuts against the end face of the support plate 5. After the abutment, the cylindrical pin as a whole only rotates without moving axially until the outer cylinders of the cylindrical pin front section 1 and the cylindrical pin rear section 3 are all ground, and then the centerless grinding is stopped to complete the processing of the workpiece.

[0031] This embodiment reduces the precision control requirements for the two-stage cylindrical pin process by a simple processing method, reduces processing costs, improves processing efficiency, and ensures the coaxiality requirements after processing by a centerless grinding method.

[0032] This embodiment breaks the conventional understanding that the original centerless grinding only grinds the entire outer circle of the entire part. In this embodiment, since the outer diameters of the front section 1 and the rear section 3 of the cylindrical pin are the same before grinding, it is easy to keep them in the same straight line before centerless grinding and continue to keep them in the same straight line during the centerless grinding process. Therefore, during the grinding process, the front section 1 and the rear section 3 of the cylindrical pin are ground at the same time, avoiding the situation where the front and rear sections of the cylindrical pin rotate relative to each other and damage the centerless grinder. At the same time, the front section 1 and the rear section 3 of the cylindrical pin are ground simultaneously by centerless grinding, ensuring the high requirement of coaxiality of 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%.

[0033] In addition, because the head 31 of the cylindrical pin rests on the support plate 5 at the last moment of the centerless grinding, the outer cylinder of the cylindrical pin front section 1 and the cylindrical pin rear section 3 are only processed by the centerless grinder under rotation, and the surface quality after grinding is higher, so the roughness of the cylindrical pin surface is also improved.

[0034] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records 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 rotational connection, characterized in that: The front section and the rear section of the cylindrical pin are assembled into a cylindrical pin semi-finished product by means of rotational connection, and then processed by centerless grinding in a state where the front section and the rear section are located in the same straight line; Among them, the outer cylinders of the front section and the rear section of the cylindrical pin before centerless grinding are both reserved with machining allowances, and the outer diameters of the front section and the rear section of the cylindrical pin with reserved machining allowances are the same.

2. The method for ensuring the coaxiality of a two-section cylindrical pin for rotational connection according to claim 1, characterized in that: During centerless grinding, the outer cylinders of the front section and the rear section of the cylindrical pin need to be completely ground.

3. The method for ensuring the coaxiality of a two-section cylindrical pin for rotational connection according to claim 1, characterized in that: Before starting the 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 state, and the front section and the rear section of the cylindrical pin are both located between the grinding wheel and the guide wheel.

4. The method for ensuring the coaxiality of a two-section cylindrical pin for rotational connection according to claim 3, characterized in that: The rear section of the cylindrical pin is provided with a head with a diameter larger than that of the outer cylinder. When the cylindrical pin is subjected to centerless grinding, the head is used to abut against the end face of the support plate.

5. A method for ensuring the coaxiality of a two-section cylindrical pin for rotational connection according to any one of claims 1 to 4, characterized in that: Before assembling the cylindrical pin semi-finished product, the front section and the rear section of the cylindrical pin are processed. The processing requirements are: except for the reserved processing allowance of the outer cylinder, the other dimensions are processed to qualified standards.

6. A method for ensuring the coaxiality of a two-section cylindrical pin for rotational connection according to claim 5, characterized in that: The cylindrical pin front section and / or the cylindrical pin rear section in the cylindrical pin semi-finished product are processed after the material is heat treated.

7. A method for ensuring the coaxiality of a two-section cylindrical pin in rotational connection according to any one of claims 1 to 4 and 6, characterized in that: The cylindrical pin front section and the cylindrical pin rear section of the cylindrical pin semi-finished product are connected by active riveting.

Images