Press-fitting device

Abstract

This enables highly accurate and reproducible press-fitting of sleeves into tubes. [Solution] The press-fitting device 100 includes a pressing mechanism 3 that brings the sleeve holding portion close to the tube holding portion 1 and presses the sleeve 81 against the tube 9. The pressing mechanism 3 includes a drive motor that linearly drives the sleeve holding portion and a torque meter that measures the torque value generated by the drive motor. A distance detection sensor 5 is provided to detect the relative distance D between the sleeve 81 and the tube 9. The control unit controls the drive motor based on the torque value measured by the torque meter and the relative distance D detected by the distance detection sensor 5.

Description

Technical Field

[0001] The present invention relates to a press-fitting device for press-fitting and attaching a sleeve inside a tube.

Background Art

[0002] In manufacturing processes such as semiconductor manufacturing, pharmaceutical manufacturing, and food processing, resin tubes may be used for transporting chemical solutions or pure water. In such technical fields, when connecting a tube with a pipe fitting, as a pre-step, a sleeve may be press-fitted and attached to one end of the tube. The pipe fitting is attached to the tube via the sleeve. An apparatus for performing such a press-fitting process is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-001277 (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Including the technology disclosed in Patent Document 1, the press-fitting of a sleeve onto a tube is generally performed manually. If the press-fitting is too weak, the seal at the connection portion becomes insufficient, leading to fluid leakage. If the press-fitting is too strong, it may cause buckling or breakage of the tube. Therefore, high precision is required for press-fitting, and the finish is likely to vary depending on the skill level of the operator.

[0005] In view of the above situation, it is desired to be able to perform the press-fitting of a sleeve onto a tube with high precision and high reproducibility.

Means for Solving the Problems

[0006] A press-fitting device for press-fitting and attaching a sleeve inside a tube, A tube holding portion for holding the tube, A sleeve holding portion that holds the sleeve coaxially with the tube, A pressing mechanism that brings the sleeve holding portion closer to the tube holding portion and presses the sleeve against the tube, It comprises a control unit and, The pressing mechanism comprises a drive motor that linearly drives the sleeve holding portion and a torque meter that measures the torque value generated by the drive motor. A distance detection sensor is provided to detect the relative distance between the sleeve and the tube. The control unit controls the drive motor based on the torque value measured by the torque meter and the relative distance detected by the distance detection sensor.

[0007] This configuration allows for the automatic press-fitting of the sleeve into the tube using the driving force generated by the drive motor. Furthermore, the control unit manages the relative distance between the tube and the sleeve, as well as the torque, thus preventing the finished product from being dependent on individual skill. Consequently, it becomes possible to achieve highly accurate and reproducible press-fitting.

[0008] Further features and advantages of the technology relating to this disclosure will become clearer from the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0009] [Figure 1] Cross-sectional view showing how tubes are connected by pipe fittings. [Figure 2] This diagram shows the state of the tube before the sleeve is pressed into it using a press-fitting device. [Figure 3] This diagram shows the state after a sleeve has been pressed into a tube using a press-fitting device. [Figure 4] Control block diagram [Figure 5] Flowchart showing the flow of the press-fitting process [Figure 6]Graph showing an example of torque input values. [Modes for carrying out the invention]

[0010] The press-fitting device according to this disclosure is a device for press-fitting a sleeve into the inside of a tube. The sleeve is press-fitted into the inside of an elastic resin tube by widening its opening. The tube is used, for example, for transporting chemicals or pure water in manufacturing processes such as semiconductor manufacturing, pharmaceutical manufacturing, and food processing. The sleeve constitutes part of a pipe joint member and is used for connecting to rotating equipment such as pumps or other tubes. Embodiments of the press-fitting device will be described below with reference to the drawings.

[0011] Figure 1 shows how the tube 9 is connected by a pipe fitting 8. The pipe fitting 8 includes a fitting body 80, a sleeve 81, and a union nut 82.

[0012] The sleeve 81 is a cylindrical component that is press-fitted through an opening formed at the tube end 90 and positioned radially inward relative to the tube 9. The inside of the sleeve 81 serves as a fluid passage.

[0013] The inner diameter of the sleeve 81 is the same as the inner diameter of the tube 9. On the other hand, the outer diameter of the sleeve 81 is larger than the outer diameter of the tube 9. In this embodiment, the sleeve 81 is equipped with a bulge 811 that expands radially outward. When the sleeve 81 is press-fitted, the bulge 811 expands the elastic tube 9 radially outward. The elastic force of the tube 9 resisting this expansion fixes the tube 9 to the sleeve 81 and seals the space between them. The bulge 811 is formed in a tapered shape that narrows towards the tip side (left side in the figure) of the sleeve 81. Therefore, even with the bulge 811, it is possible to properly press-fit the sleeve 81 into the tube 9.

[0014] In this embodiment, the sleeve 81 includes a stepped portion 812 whose radial dimension varies. The stepped portion 812 is a portion where the outer peripheral surface of the sleeve 81 changes stepwise. The stepped portion 812 has a surface facing the tip side in the axial direction (the left side in the figure). The stepped portion 812 is formed on the base end side (the right side in the figure) of the sleeve 81 with respect to the bulging portion 811. The stepped portion 812 (specifically, the surface facing the tip side in the axial direction in the stepped portion 812) faces the tube end 90 in the axial direction.

[0015] The joint body 80 is a member formed in a cylindrical shape and includes an inner cylinder portion 801 and an outer cylinder portion 802 formed with a larger diameter than the inner cylinder portion 801. The inner cylinder portion 801 is configured to be fitted in the axial direction with the base end (the end on the left side in the figure) of the sleeve 81. The outer cylinder portion 802 is configured to cover, from the outside in the radial direction, the portion of the tube 9 expanded by the sleeve 81. The tube 9 is adjacently arranged on the inner side in the radial direction of the outer cylinder portion 802, and the sleeve 81 is adjacently arranged further on the inner side in the radial direction thereof.

[0016] The union nut 82 is press - contacted from the outside in the radial direction to the tube 9 and is screwed from the outside in the radial direction to the joint body 80. By tightening the union nut 82 to the joint body 80, the connection process of the tube 9 by the pipe joint 8 is completed.

[0017] The press - fitting device 100 (see FIG. 2 etc.) according to the present disclosure is used for the press - fitting process of the sleeve 81 performed before the above - described connection process. By the press - fitting process, the sleeve 81 is attached to the tube 9.

[0018] FIG. 2 and FIG. 3 show the press - fitting device 100 according to this embodiment. FIG. 2 is before press - fitting, and FIG. 3 is after press - fitting. Here, an example of a mounting - type press - fitting device 100 used in a state of being placed on a stand or the like is illustrated.

[0019] The press-fitting device 100 includes a tube holding portion 1 that holds the tube 9, a sleeve holding portion 2 that holds the sleeve 81 coaxially with the tube 9, and a pressing mechanism 3 that brings the sleeve holding portion 2 closer to the tube holding portion 1 to press the sleeve 81 against the tube 9. The tube holding portion 1 and the sleeve holding portion 2 are connected by a connecting portion 4 and are integrated. In this embodiment, the sleeve holding portion 2 is configured to linearly move along the axial direction by the pressing mechanism 3 and approach or separate coaxially with respect to the tube 9.

[0020] In this embodiment, the tube holding portion 1 is configured using a clamp. The tube holding portion 1 includes a fixed portion and a movable portion. The movable portion is configured to be openable and closable with respect to the fixed portion. In the state where the movable portion is closed, the movable portion and the fixed portion form an annular shape, and the tube 9 is held between them. The tube holding portion 1 is configured to be able to hold a plurality of types of tubes 9 having different diameters. For example, the tube holding portion 1 is configured to hold the tube 9 via a ring member, and by adjusting the thickness of the ring member, it can correspond to different diameters of the tube 9.

[0021] In this embodiment, the sleeve holding portion 2 includes a support shaft 20 disposed coaxially with the tube 9 held by the tube holding portion 1 and a sleeve holder 21 that holds the sleeve 81.

[0022] The support shaft 20 is configured to support the sleeve holder 21 from the inside in the radial direction. The support shaft 20 can support a plurality of types of sleeve holders 21.

[0023] The sleeve holder 21 is interchangeable with respect to the support shaft 20. There are several types of sleeve holders 21, and the appropriate size is selected according to the size of the sleeve 81 to be held. As shown in the figure, the tip of the sleeve holder 21 protrudes from the sleeve 81 and is tapered, continuing from the bulging portion 811 of the sleeve 81. This allows the tube 9 to be guided relative to the sleeve 81 when the sleeve 81 is pressed into the tube 9, enabling smooth press-fitting.

[0024] In this embodiment, the pressing mechanism 3 is configured to move the sleeve holding portion 2 linearly along the axial direction, bringing it closer to or further away from the tube 9 coaxially.

[0025] As shown in Figure 4, the pressing mechanism 3 is equipped with a drive motor 31 that linearly drives the sleeve holding portion 2. That is, the linear motion of the sleeve holding portion 2 is achieved using the drive motor 31. However, the pressing mechanism 3 according to this embodiment is equipped with an operating lever 30 (see Figures 2 and 3), and the linear motion of the sleeve holding portion 2 can also be achieved manually by the operator. In this embodiment, the sleeve holding portion 2 may be manually moved in a partial phase of the press-fitting process.

[0026] In the press-fitting device 100 according to this disclosure, the torque value required for press-fitting and the relative distance D between the tube 9 and the sleeve 81 after press-fitting (see Figure 3) are used as indicators of whether the sleeve 81 has been properly pressed into the tube 9.

[0027] As shown in Figure 4, the pressing mechanism 3 is equipped with a torque meter 32 that measures the torque value generated by the drive motor 31. The torque meter 32 is configured to measure torque using an index based on the magnitude of the current or voltage (an index equivalent to the torque value).

[0028] Furthermore, the press-fitting device 100 is equipped with a distance detection sensor 5 that detects the relative distance D between the sleeve 81 and the tube 9.

[0029] Furthermore, the press-fitting device 100 includes a control unit 6 that controls the drive motor 31 based on the torque value measured by the torque meter 32 and the relative distance D value detected by the distance detection sensor 5. The control unit 6 may automatically control the drive motor 31 while automatically acquiring both of these values, or it may control the drive motor 31 according to a command value input by the operator based on both of these values. In other words, whether the drive motor 31 is controlled automatically or according to the operator's instructions, the control unit 6 will control the drive motor 31 based on the torque value measured by the torque meter 32 and the relative distance D value detected by the distance detection sensor 5.

[0030] As shown in Figure 3, the relative distance D between the tube 9 and the sleeve 81 is the axial gap between the tube end 90 of the tube 9 and the stepped portion 812 of the sleeve 81. The press-fitting device 100 controls the drive motor 31 so that this relative distance D becomes a predetermined specified distance, thereby press-fitting the sleeve 81 into the tube 9. The "specified distance" is determined by experiments, etc., and should be set to a distance that is sufficiently short to ensure the sealing performance of the connection part by the pipe joint 8 (see Figure 1), but it may vary depending on the operating environment of the press-fitting device 100 and the standards of the user using the press-fitting device 100. If the relative distance D after press-fitting is greater than the specified distance, the sealing performance will be insufficient, and if it is smaller than the specified distance, it may lead to buckling or damage of the tube 9. Therefore, appropriate management of the relative distance D is required.

[0031] As shown in Figure 3, the distance detection sensor 5 is positioned radially outward relative to the tube end 90. This allows for accurate detection of the relative distance D, which is the axial gap between the tube end 90 and the stepped portion 812 of the sleeve 81, from the radially outward direction. In the illustrated example, the distance detection sensor 5 is positioned directly below the tube end 90. The distance detection sensor 5 is fixed to the connecting portion 4. However, in order to position the distance detection sensor 5 directly below the tube end 90, the axial position of the distance detection sensor 5 may be configured to be adjustable. In this embodiment, the distance detection sensor 5 is configured using a camera.

[0032] In the press-fitting process, as shown in Figure 2, the tube 9 is set in the tube holding part 1 and the sleeve 81 is set in the sleeve holding part 2. Then, although detailed illustrations are omitted, the sleeve holding part 2 is moved linearly to insert a portion of the sleeve holder 21 into the inside of the tube end 90. At this time, it is preferable that the tip portion of the sleeve holder 21 is inserted slightly into the inside of the tube 9. The linear movement of the sleeve holding part 2 to create this state may be performed by the drive motor 31 or by the operator operating the operating lever 30.

[0033] Then, the sleeve holding part 2 is linearly driven by the drive motor 31, and as shown in Figure 3, the sleeve 81 is press-fitted into the tube 9. This attaches the sleeve 81 to the tube 9.

[0034] In this embodiment, the control unit 6 controls the drive motor 31 within a predetermined torque range TR (see Figure 6). The control unit 6 stops the drive motor 31 if the torque exceeds the upper limit of the predetermined torque range TR while the sleeve 81 is pressing against the tube 9. If the torque exceeds the upper limit of the predetermined torque range TR, i.e., if an unexpectedly large torque is applied, it can be determined that some abnormality has occurred, such as a jam in the linear motion mechanism of the sleeve holding part 2 or excessive press-fitting. In this case, the drive motor 31 is stopped, preventing further application of excessive torque. After the drive motor 31 stops, the operator can visually check for any abnormalities.

[0035] Figure 5 is a flowchart showing the flow of the press-fitting process.

[0036] As shown in Figure 5, the control unit 6 commands the drive motor 31 to generate torque within a specified torque range TR (see Figure 6), thereby inputting torque to the sleeve holding unit 2 (#1). More specifically, torque is input to the linear motion mechanism that moves the sleeve holding unit 2 in a linear motion. As a result, the sleeve holding unit 2 moves linearly toward the tube 9, and the sleeve 81 held by the sleeve holding unit 2 is pressed into the inside of the tube 9. The torque meter 32 measures the torque value in parallel with the press-fitting.

[0037] Once the press-fitting is complete to a certain extent, the distance detection sensor 5 detects the relative distance D between the tube 9 and the sleeve 81 (see Figure 3), that is, the axial gap between the tube end 90 and the stepped portion 812 of the sleeve 81 (#2). In other words, in this embodiment, the torque input and the detection of the relative distance D are performed at separate timings.

[0038] If the relative distance D is less than the specified distance (#3: No), the input torque is increased (#4), and the press-fitting continues. After step #4, the process returns to step #2, and the relative distance D is detected again. In other words, in this embodiment, the distance detection sensor 5 is configured to detect the relative distance D each time the torque increases. In the example shown in Figure 6, the drive motor 31 is configured to gradually increase the torque within the specified torque range TR.

[0039] For example, the control unit 6 transmits a first torque Ta as a command value to the drive motor 31, and the drive motor 31 generates the first torque Ta. Subsequently, the relative distance D is detected, and if it is less than the specified distance, the control unit 6 transmits a second torque Tb, which is greater than the first torque Ta, as a command value to the drive motor 31, and the drive motor 31 generates the second torque Tb. Further on, the relative distance D is detected again, and if it is still less than the specified distance, the control unit 6 transmits a third torque Tc, which is greater than the second torque Tb, as a command value to the drive motor 31, and the drive motor 31 generates the third torque Tc.

[0040] Returning to Figure 5, if the relative distance D matches the specified distance (#3: Yes), the press-fitting is complete. The control unit 6 stops the drive motor 31.

[0041] In this embodiment, after the press-fitting is complete, the control unit 6 commands the drive motor 31 to generate a negative torque, thereby inputting a negative torque to the sleeve holding part 2 (#5). That is, in this embodiment, when the relative distance D reaches a predetermined distance, the control unit 6 reverses the rotation of the drive motor 31. As a result, the sleeve holding part 2 retracts away from the tube 9, and the sleeve holder 21 is pulled out of the tube 9 while the tube 9 and the sleeve 81 remain connected.

[0042] As shown in Figure 6, after the press-fitting is complete, the control unit 6 transmits a negative torque Td as a command value to the drive motor 31, and the drive motor 31 generates the negative torque Td. As a result, the drive motor 31 rotates in reverse, and the sleeve holder 21 is pulled out of the tube 9.

[0043] [Other Embodiments] Next, other embodiments will be described.

[0044] (1) In the above embodiment, an example was described in which the relative distance D between the tube 9 and the sleeve 81 is the axial gap between the tube end 90 of the tube 9 and the stepped portion 812 of the sleeve 81. However, the example is not limited to this example, and the relative distance D may be defined based on any part of the tube 9 and any part of the sleeve 81.

[0045] (2) In the above embodiment, an example was described in which the distance detection sensor 5 is positioned directly below the tube end 90. However, the example is not limited to this, and the distance detection sensor 5 may be positioned, for example, directly above the tube end 90, or directly to the side. In any case, it is preferable that the distance detection sensor 5 be positioned directly away from the tube end 90 in the radial direction.

[0046] (3) In the above embodiment, an example was described in which torque input and detection of the relative distance D are performed at different timings. However, the example is not limited to this, and these may occur simultaneously. That is, the sleeve holding part 2 may be moving in a straight line due to the torque input, and at the same time, the distance detection sensor 5 may continue to detect the relative distance D. With this configuration, the drive motor 31 can be stopped at the timing when the relative distance D matches a specified distance.

[0047] (4) In the above embodiment, an example was described in which the sleeve holder 21 is pulled out of the tube 9 by rotating the drive motor 31 in the reverse direction after press-fitting. However, the invention is not limited to this example, and the sleeve holder 21 may be pulled out of the tube 9 by the operator operating the operating lever 30.

[0048] (5) In the above embodiment, a stationary press-fitting device 100 was illustrated. However, the invention is not limited to such an example, and for example, the press-fitting device 100 may be a handheld type that can be held in the hand by the operator while press-fitting is performed. A handheld press-fitting device 100 is intended for tubes 9 with a relatively small diameter.

[0049] (6) The configurations disclosed in the embodiments described above can also be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate without departing from the spirit of this disclosure.

[0050] [Summary of this embodiment] The following is a summary of this embodiment.

[0051] A press-fitting device for attaching a sleeve to the inside of a tube by press-fitting it, A tube holding portion for holding the tube, A sleeve holding portion that holds the sleeve coaxially with the tube, A pressing mechanism that brings the sleeve holding portion closer to the tube holding portion and presses the sleeve against the tube, It comprises a control unit and, The pressing mechanism comprises a drive motor that linearly drives the sleeve holding portion and a torque meter that measures the torque value generated by the drive motor. A distance detection sensor is provided to detect the relative distance between the sleeve and the tube. The control unit controls the drive motor based on the torque value measured by the torque meter and the relative distance detected by the distance detection sensor.

[0052] This configuration allows for the automatic press-fitting of the sleeve into the tube using the driving force generated by the drive motor. Furthermore, the control unit manages the relative distance between the tube and the sleeve, as well as the torque, thus preventing the finished product from being dependent on individual skill. Consequently, it becomes possible to achieve highly accurate and reproducible press-fitting.

[0053] Preferably, the control unit stops the drive motor if, while the sleeve is pressing against the tube, the torque exceeds a predetermined upper limit of a specified torque range.

[0054] With this configuration, if the torque exceeds the upper limit of the specified torque range, the drive motor is stopped, thereby preventing excessive load from being placed on the tube.

[0055] The drive motor is configured to gradually increase the torque within the specified torque range. Preferably, the distance detection sensor is configured to detect the relative distance each time the torque increases.

[0056] This configuration makes it easier to bring the relative distance closer to an ideal value while avoiding excessive torque.

[0057] Preferably, the control unit reverses the rotation of the drive motor when the relative distance reaches a predetermined distance.

[0058] With this configuration, the release of the press-fit mechanism can also be performed automatically. [Industrial applicability]

[0059] The technology described herein can be used in a press-fitting device that press-fits a sleeve into the inside of a tube. [Explanation of Symbols]

[0060] 100: Press-fitting device 1: Tube holding part 2: Sleeve holding section 3: Pressing mechanism 31: Drive motor 32: Torque meter 5: Distance detection sensor 6: Control Unit 9: Tube 81: Sleeves D: Relative distance TR: Specified torque range

Claims

1. A press-fitting device for attaching a sleeve to the inside of a tube by press-fitting it, A tube holding portion for holding the tube, A sleeve holding portion that holds the sleeve coaxially with the tube, A pressing mechanism that brings the sleeve holding portion closer to the tube holding portion and presses the sleeve against the tube, It comprises a control unit and, The pressing mechanism comprises a drive motor that linearly drives the sleeve holding portion and a torque meter that measures the torque value generated by the drive motor. A distance detection sensor is provided to detect the relative distance between the sleeve and the tube. The relative distance to be detected by the distance detection sensor is the axial gap formed between the tube and the sleeve. The control unit controls the drive motor based on the torque value measured by the torque meter and the relative distance detected by the distance detection sensor in the press-fitting device.

2. The press-fitting device according to claim 1, wherein the control unit stops the drive motor if the torque becomes greater than the upper limit of a predetermined torque range while the sleeve is pressing against the tube.

3. The drive motor is configured to gradually increase the torque within the specified torque range. The press-fitting device according to claim 2, wherein the distance detection sensor is configured to detect the relative distance each time the torque increases.

4. The press-fitting device according to any one of claims 1 to 3, wherein the control unit reverses the rotation of the drive motor when the relative distance becomes a predetermined distance.

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