Automatic assembling method for array or multiple pin shaft and hole workpieces

Abstract

The invention discloses an automatic assembling method for an array or multiple pin shaft and hole workpiece, and relates to the technical field of pin shaft assembling, the outer surface or some characteristics of a to-be-assembled part is used as a rough reference, the workpiece is clamped in a floating pre-positioning mode, then the assembled characteristic is used as a fine reference, alignment is conducted through an alignment mechanism, and fine reference positioning is achieved. And the workpiece is clamped and fixed for press-fitting work. According to the automatic assembling method for the array or multiple pin shaft and hole workpieces, the shaft hole assembling precision is greatly improved, accurate positioning of the pin holes can be completed, automatic feeding of the pin shafts and automatic centering of the pin shafts and the holes can be completed, and accurate press fitting work of the pin shafts and the holes is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of pin assembly, and in particular to an automated assembly method for an array or a plurality of pins and a hole workpiece. Background Art

[0002] In the process of mechanical installation and production, when large torque needs to be transmitted between some parts or the connection needs to be prevented from falling off, interference fit is often used for tight fit. The principle of interference fit is to use the elasticity of the material to expand and deform the hole so that it can be sleeved on the shaft. When the hole is restored, a clamping force on the shaft is generated, thereby connecting the two parts. Interference fit is widely used in modern mechanical processing and production processes because of its simple structure, good neutrality, convenient torque transmission, and strong load-bearing capacity.

[0003] There are three methods of interference fitting: cold fitting, hot fitting, and press fitting. In the field of automated assembly, press fitting is often used to meet the requirements of mass production and production line automation. However, in the process of automated press fitting, if the connection performance cannot be quantitatively measured and precisely controlled, the quality of the hole-shaft interference fit will usually deteriorate. Due to the complex and irregular shapes of the workpiece structure, the lack of precise dimensional relationship between the pin hole and its outer surface, and the inability to directly accurately position the pin hole through the outer surface, it is difficult to achieve automated assembly of the shaft hole of the workpiece with irregular surfaces, which has brought tremendous pressure to existing manufacturers for mass production.

[0004] According to the automatic centering press-fitting tool disclosed in publication number CN107877154A, the press-fitting tool divides the press rod into three sections, and the three sections are flexibly connected, so that the press rod can be automatically centered under the action of pressure. However, this invention still belongs to the automatic centering tool in the press-fitting process and fails to achieve overall automation. According to the automatic press-fitting device disclosed in publication number CN118544099 A, the ball to be packaged and the process hole are fixed to the specified position by mechanical positioning, and then press-fitting is performed to improve efficiency and qualified rate, but the loading and unloading are all done manually, and it is impossible to achieve full automatic operation.

[0005] The shaft hole assembly in the existing related technology is generally carried out by manual press fitting. Due to the manual press fitting, the work efficiency is low. At the same time, due to the different experience of operators, the positioning accuracy of the manually aligned shaft holes is poor, which can easily lead to excessive contact stress during the interference fit of the shaft holes, causing damage to parts or improper assembly, resulting in uneven pass rates of pressed products and poor product consistency. Summary of the invention

[0006] The purpose of the present invention is to provide an automated assembly method for an array or multiple pin shafts and hole workpieces, so as to solve the problems of low working efficiency and poor shaft hole positioning accuracy of the assembly method in the prior art.

[0007] To achieve the above object, the present invention provides an automated assembly method for an array or a plurality of pins and hole workpieces, comprising the following steps:

[0008] S1. Place the workpiece to be assembled on the fixture, but do not clamp it, and use the pre-positioning tool on the fixture to pre-position the workpiece to be assembled;

[0009] S2. The workpiece to be assembled is sent to the assembly station of the pin hole to be assembled through the motion platform, and the pin hole and the pressure head are in a vertical line;

[0010] S3, extend the pressure head, insert it into the pin hole, align the pin hole with the pressure head, and determine the position of the pin hole;

[0011] S4, the clamping mechanism and the guide clamping mechanism are pressed down to fix the position of the pin hole;

[0012] S5, the pressure head retracts, and the pin shaft is sent to the front end of the push-pull mechanism through the pin sending mechanism, and the push-pull mechanism sends the pin shaft to the pin hole;

[0013] S6, the pressure head is pressed down to press the pin shaft, and after the press-fitting is completed, the pressure head is retracted, and the clamping mechanism and the guide clamping mechanism are lifted up;

[0014] S7. Repeat steps S1-S6 until all holes are pressed and installed. The clamping mechanism is released and the workpiece is sent to the unloading position through the motion platform to complete unloading.

[0015] Preferably, the fixture is mounted on a motion platform, and the motion platform is driven by a motor.

[0016] Preferably, the fixture comprises a clamping body, a pre-positioning tool and a clamping mechanism, the clamping mechanism is arranged on the clamping body, the clamping body is connected to the pre-positioning tool, and the pre-positioning tool pre-positions the workpiece to be assembled.

[0017] Preferably, the pressure head is arranged on the upper part of the guide pressing mechanism, and the size design of the pressure head should meet the following requirements:

[0018]

[0019] Wherein, d1 is the diameter of the cylindrical part of the pressure head; D0 is the diameter of the pin hole; Δδ is the floating range of the pin hole after pre-positioning; ΔL is the cumulative position tolerance of the multi-hole position.

[0020] Preferably, the front end of the guide and clamping mechanism is arranged as a trapezoidal structure, and a through hole is arranged at the front end, and the through hole is arranged concentrically and coaxially with the pressure head.

[0021] Preferably, the pin-feeding mechanism is arranged on the upper part of the guiding and clamping mechanism, and a detector is arranged at the front end of the pin-feeding mechanism.

[0022] Preferably, the push-pull mechanism is arranged on the guide clamping structure, the push-pull mechanism is arranged at the lower part of the pressure head and the pin-delivering mechanism, and the end of the pin-delivering mechanism is coaxially arranged with the end of the push-pull mechanism.

[0023] Therefore, the present invention adopts the above-mentioned automated assembly method for array or multiple pin shafts and hole workpieces, and converts the errors such as reference position and reference misalignment in traditional assembly into the matching errors between the alignment mechanism and the pin hole, thereby greatly improving the shaft-hole assembly accuracy, and solving the problem of shaft-hole assembly in which the outer surfaces have no accurate dimensional relationship and the assembly holes cannot be accurately positioned directly through the outer surfaces. This greatly improves the assembly accuracy and efficiency, and provides a new idea for the automation and intelligent transformation of enterprises.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the assembly structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the final positioning method of the present invention;

[0027] Figure 3 It is a schematic diagram of the pin feeding and guiding method of the present invention;

[0028] Figure 4 for Figure 3 A magnified view of the structure at center;

[0029] Figure 5 It is a schematic diagram of the self-positioning reference assembly technology route of the present invention;

[0030] Reference numerals

[0031] 1. Motion platform; 2. Clamp; 3. Guide and clamping mechanism; 4. Sales promotion mechanism; 5. Pin delivery mechanism; 6. Clamping mechanism; 7. Press head; 8. Workpiece to be assembled; 9. Pin hole; 10. Pin shaft. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0033] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] Example

[0035] See also Figure 1-5 The present invention provides an automated assembly method for an array or a plurality of pins and hole workpieces, comprising the following steps:

[0036] S1. Place the workpiece 8 to be assembled on the fixture 2, but do not clamp it. Use the pre-positioning tool on the fixture 2 to pre-position the workpiece 8 to be assembled.

[0037] S2. The workpiece 8 to be assembled is sent to the assembly station of the pin hole 9 to be assembled through the motion platform 1, and the pin hole 9 and the pressing head 7 are roughly on a vertical line.

[0038] S3, extend the pressure head 7, insert it into the pin hole 9, but not insert it to the bottom, align the pin hole 9 by the pressure head 7, and determine the position of the pin hole 9.

[0039] S4, the clamping mechanism 6 and the guide clamping mechanism 3 are pressed down to fix the position of the pin hole 9.

[0040] S5, the pressure head 7 retracts, and the pin shaft 10 is sent to the front end of the push-pull mechanism 4 through the pin sending mechanism 5, and the push-pull mechanism 4 sends the pin shaft 10 to the pin hole 9.

[0041] S6, the pressing head 7 is pressed down to press the pin shaft 10. After the press-fitting is completed, the pressing head 7 is retracted, and the clamping mechanism 6 and the guide clamping mechanism 3 are lifted up.

[0042] S7, repeat steps S1-S6 until all holes are press-fitted, the clamping mechanism 6 is released, and the workpiece is sent to the unloading position through the motion platform 1 to complete the unloading.

[0043] The motion platform 1 is used to move to different press-fitting stations when different pin holes 9 need to be press-fitted, so as to complete the subsequent final positioning and press-fitting operations. The press-fitting station is the position of the motion platform 1 corresponding to when the pin hole 9 is below the press head. The motion platform 1 can be driven in a variety of ways.

[0044] The fixture 2 is installed on the motion platform 1. The fixture 2 includes a fixture body, a pre-positioning tool and a clamping mechanism 6. The clamping mechanism 6 is arranged on the fixture body. The fixture body is connected to the pre-positioning tool. The pre-positioning tool pre-positions the workpiece to be assembled. The pre-positioning tool can adopt a variety of methods such as two pins on one side, positioning pins, mandrels or cone tips, support pins, etc. The methods can be various. The purpose of the pre-positioning tool is to limit the degree of freedom of the workpiece itself so that it can only float within a smaller range, thereby confirming the approximate position of the hole to be assembled. Different positioning errors can be calculated through the positioning errors of different positioning methods. The positioning error is defined as Δδ, that is, the floating range of the pin hole of the workpiece after pre-positioning is Δδ.

[0045] The pressure head 7 is arranged on the upper part of the guide clamping mechanism 3. The workpiece is positioned and pressed by controlling the pressure head 7 to move up and down. The pressure head 7 is mainly used for final positioning of the workpiece and subsequent pressing work in the pre-positioned state of the workpiece. Figure 2 As shown, the final positioning and alignment process is: insert the pressure head 7 into the pin hole 9 for alignment. At this time, the pressure head 7 can be regarded as a positioning pin. The clearance between the pressure head 7 and the pin hole 9 is used to align the precise position of the pin hole 9 on the surface of the workpiece in the pre-positioned state, and the pin hole 9 is accurately positioned, thereby ensuring the precise position relationship between the pin hole 9 and the pressure head 7. In the final positioning and alignment process, in order to ensure that the pressure head 7 can be smoothly inserted into the hole to complete the alignment, the diameter of the cylindrical part of the pressure head 7 needs to be smaller than the minimum diameter of the pin hole 9, that is: d1≤D 0min .

[0046] The alignment range of the workpiece during the final positioning and alignment process depends on the guide range of the pressure head, that is, the diameter difference between the cylindrical part and the chamfered part of the pressure head 7; further, when a single pin hole 9 is pressed, in order to achieve smooth alignment, the floating range of the workpiece pin hole 9 should be smaller than the alignment range of the pressure head 7, otherwise the alignment cannot be achieved, that is, d1-d2≥△δ. When pressing an array or multiple pin holes 9, it is necessary not only to consider the floating range of the workpiece pin hole 9 in the pre-positioning state, but also to consider the position tolerance between the holes. Usually, between a single pin hole 9 and a pin hole 9, the tolerance △L1 is usually only between 0.1, which can be ignored. However, when there are many holes to be assembled, the tolerance will be accumulated, and the tolerance of this part is totaled as △L. Therefore, at this time, the alignment range of the pressure head 7 should be greater than the sum of the floating range of the workpiece pin hole and the accumulated position tolerance of multiple holes, expressed as d1-d2≥△δ+△L.

[0047] In the subsequent press-fitting work, the lower part of the pressing head 7 needs to push the pin 10 to complete the press-fitting operation. If the contact surface is smaller, the pressure will be greater, and the requirements for the material and the overall structural strength of the pin 10 will be higher. Therefore, the area of ​​the lower surface d2 of the pin 10 should be increased as much as possible within the allowable range, so d2 should satisfy d2≤d1-△δ-△L.

[0048] After the final positioning is completed, the error source only comes from the matching clearance Δ' between the pressure head 7 and the pin hole 9. The matching clearance is the diameter difference between the minimum diameter of the pin hole 9 and the pressure head 7, that is, Δ'=D 0min -d1, if Δ' is smaller, it means the positioning error is smaller and the positioning is more accurate. Theoretically, Δ' can be infinitely close to 0, so d1 should satisfy d1≤D 0min .

[0049] The design of the pressure head should meet the requirement that the diameter of the cylindrical part is smaller than the minimum diameter of the pin hole 9, d1≤D 0min The chamfered part should satisfy d2≤d1-△δ-△L.

[0050] The guiding and clamping mechanism 3 and the clamping mechanism 6 work together to fix the workpiece after the workpiece is finally positioned. In addition, the guiding and clamping mechanism 3 also guides the pin 10 during the press-fitting process. Figure 3 As shown, the front end of the guide clamping mechanism 3 is trapezoidal, and there is a through hole at the front end, and the through hole is coaxial and concentric with the pressure head 7. During the final positioning process, the pressure head 7 passes through the through hole and is inserted into the pin hole 9 on the workpiece for alignment to complete the final positioning of the workpiece. At this time, the pressure head 7, the pin hole 9 and the through hole at the front end of the guide clamping mechanism 3 are concentric. After the final positioning is completed, the guide clamping mechanism 3 and the clamping mechanism 6 are pressed down at the same time to complete the fixation of the workpiece, and then the pressure head 7 is lifted up, and the push-pull mechanism 4 pushes the pin shaft 10 forward and sends the pin shaft 10 to this through hole, so that the pin shaft 10, the pressure head 7 and the pin hole 9 are concentric, completing the guided feeding operation of the pin shaft 10. In order to meet the guiding and feeding function of the pin shaft 10, the diameter of the through hole should be slightly larger than the diameter of the pin shaft 10, and should not be too large, otherwise it will lose the guiding function, that is, d3≥D1.

[0051] The pin delivery mechanism 5 is arranged on the upper part of the guide clamping mechanism 3. The pin delivery mechanism 5 is arranged in parallel with the pressure head 7. The pin delivery mechanism 5 is mainly used to deliver the pin shaft 10 to the front end of the sales promotion mechanism 4. The pin delivery method can be pneumatic, mechanical or manual. The front end of the pin delivery mechanism 5 should be equipped with a detector, which can cooperate with a photoelectric sensor, a magnetic induction sensor or a weight sensor to complete the pin delivery detection of the pin shaft 10 to ensure that the pin shaft 10 is delivered to the sales promotion mechanism 4. The sales promotion mechanism 4 is installed on the guide clamping mechanism 3 to push the pin shaft 10 delivered by the pin delivery mechanism 5 to the through hole at the front end of the guide clamping mechanism 3. The sales promotion method can be a cylinder, an electric cylinder, an oil cylinder, etc. to ensure that its stroke can meet the requirements of pushing the pin shaft 10 to the front end of the guide clamping mechanism 3. The sales promotion mechanism 4 and the pin delivery mechanism 5 jointly complete the feeding work of the pin shaft in the press-fitting operation.

[0052] Therefore, the present invention adopts the above-mentioned automated assembly method for array or multiple pin shafts and hole workpieces, and converts the errors such as reference position and reference misalignment in traditional assembly into the matching errors between the alignment mechanism and the pin hole, thereby greatly improving the shaft-hole assembly accuracy, and solving the problem of shaft-hole assembly in which the outer surfaces have no accurate dimensional relationship and the assembly holes cannot be accurately positioned directly through the outer surfaces. This greatly improves the assembly accuracy and efficiency, and provides a new idea for the automation and intelligent transformation of enterprises.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An automated assembly method for an array or multiple pins and holes workpiece, characterized in that: The following steps are involved: S1. Place the workpiece to be assembled on the fixture, but do not clamp it, and use the pre-positioning tool on the fixture to pre-position the workpiece to be assembled; S2. The workpiece to be assembled is sent to the assembly station of the pin hole to be assembled through the motion platform, and the pin hole and the pressure head are in a vertical line; S3, extend the pressure head, insert it into the pin hole, align the pin hole with the pressure head, and determine the position of the pin hole; S4, the clamping mechanism and the guide clamping mechanism are pressed down to fix the position of the pin hole; S5, the pressure head retracts, and the pin shaft is sent to the front end of the push-pull mechanism through the pin sending mechanism, and the push-pull mechanism sends the pin shaft to the pin hole; S6, the pressure head is pressed down to press the pin shaft, and after the press-fitting is completed, the pressure head is retracted, and the clamping mechanism and the guide clamping mechanism are lifted up; S7. Repeat steps S1-S6 until all holes are pressed and installed. The clamping mechanism is released and the workpiece is sent to the unloading position through the motion platform to complete unloading.

2. An automated assembly method for an array or a plurality of pins and hole workpieces according to claim 1, characterized in that: The fixture is installed on a motion platform, and the motion platform is driven by a motor.

3. An automated assembly method for an array or a plurality of pins and hole workpieces according to claim 2, characterized in that: The fixture comprises a clamp body, a pre-positioning tool and a clamping mechanism. The clamping mechanism is arranged on the clamp body. The clamp body is connected with the pre-positioning tool. The pre-positioning tool pre-positions the workpiece to be assembled.

4. An automated assembly method for an array or a plurality of pins and holes workpiece according to claim 3, characterized in that: The pressure head is set on the upper part of the guide clamping mechanism, and the size design of the pressure head should meet the following requirements: Wherein, d1 is the diameter of the cylindrical part of the pressure head; D0 is the diameter of the pin hole; Δδ is the floating range of the pin hole after pre-positioning; ΔL is the cumulative position tolerance of the multi-hole position.

5. An automated assembly method for an array or a plurality of pins and hole workpieces according to claim 4, characterized in that: The front end of the guide pressing mechanism is arranged as a trapezoidal structure, and a through hole is arranged at the front end, and the through hole is arranged coaxially and concentrically with the pressing head.

6. An automated assembly method for an array or a plurality of pins and hole workpieces according to claim 5, characterized in that: The pin-feeding mechanism is arranged on the upper part of the guiding and clamping mechanism, and a detector is arranged at the front end of the pin-feeding mechanism.

7. An automated assembly method for an array or a plurality of pins and hole workpieces according to claim 6, characterized in that: The push-pushing mechanism is arranged on the guide clamping structure, the push-pushing mechanism is arranged at the lower part of the pressure head and the pin-delivering mechanism, and the end of the pin-delivering mechanism is coaxially arranged with the end of the push-pushing mechanism.

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