Cap screwing control method and servo cap screwing machine

Abstract

The invention discloses a cap screwing control method and a servo cap screwing machine, and belongs to the technical field of cap screwing, and the cap screwing control method comprises the steps that S1, a servo motor is started, the output rotating speed of the servo motor is controlled to be increased to a first rotating speed, and therefore a cap screwing assembly is driven to drive a bottle cap to rotate at the first rotating speed; s2, the output torque of the servo motor and the number of rotation turns of the bottle cap are detected, when the output torque reaches a first torque threshold value or the number of rotation turns reaches a preset number of turns, the output rotation speed is controlled to be switched from the first rotation speed to the second rotation speed, and meanwhile the output torque is controlled to be increased; and S3, after the output torque reaches the second torque threshold value, the servo motor is controlled to operate with the output torque kept at the second torque threshold value. The servo cap screwing machine is applied to the cap screwing control method.

Description

Technical Field

[0001] The present invention relates to the technical field of capping, and in particular to a capping control method and a servo capping machine. Background Art

[0002] In the liquid packaging industry, a capping machine is usually used to fix the cap on the bottle to seal the bottle. The capping machine is a sealing device that fastens the cap to the bottle filled with the product. The size of the capping torque of the capping machine directly affects the sealing performance of the bottle seal and the torque required for consumers to open the cap. Specifically, the greater the capping torque, the better the sealing performance of the seal, the greater the torque required when opening the cap, the more difficult it is for consumers to open the cap, and the poorer the acceptance; conversely, the smaller the capping torque, the worse the sealing performance of the seal. If the capping torque is too small, leakage may occur, thereby losing the sealing effect. At this time, although the opening torque is small, it is meaningless. Therefore, the capping torque must find a balance between sealing performance and opening force, with both high sealing performance and as small opening torque as possible.

[0003] In the prior art, capping is performed by a servo capping machine, which includes a servo motor and a capping assembly. The capping assembly can grab the cap and then put the cap on the bottle. The servo motor is used to drive the capping assembly to rotate so as to screw the cap on the bottle. The servo motor drives the capping assembly to rotate according to the set torque until the feedback torque received by the servo motor is greater than the maximum torque. Among them, the set torque and the maximum torque can be obtained according to experiments or theoretical calculations, so that the capping assembly can smoothly install the cap on the bottle under the drive of the servo motor, and has a high sealing performance, will not leak, and will not have the problem of too much torque required when opening the cap, which is within the acceptable level for users.

[0004] However, in actual operation, since the servo motor is usually connected to the capping assembly through a transmission chain or other connecting structures, when the servo motor receives a feedback torque that is the maximum torque and stops outputting torque, the capping machine will have rotational inertia. Under the action of the rotational inertia, the capping assembly cannot stop capping immediately, but will continue to capping, causing the capping torque to continue to increase, and then the capping torque will be greater than the allowable range of the opening torque, affecting the capping effect. Summary of the invention

[0005] The purpose of the present invention is to provide a capping control method and a servo capping machine to solve the technical problem that the capping control method in the prior art is affected by the inertia moment of the transmission chain, resulting in slow feedback of the transmission chain and excessive capping torque, which leads to difficulty in opening the cap.

[0006] As conceived above, the technical solution adopted by the present invention is:

[0007] In one aspect, the present invention provides a capping control method, comprising:

[0008] S1, starting the servo motor and controlling the output speed of the servo motor to increase to a first speed, thereby driving the capping assembly to drive the bottle cap to rotate at the first speed;

[0009] S2, detecting the output torque of the servo motor and the number of rotations of the bottle cap, and when the output torque reaches a first torque threshold or the number of rotations reaches a preset number of rotations, controlling the output speed to switch from the first speed to the second speed, and controlling the output torque to increase;

[0010] S3. When the output torque reaches a second torque threshold, controlling the servo motor to maintain the output torque at the second torque threshold.

[0011] Preferably, the number of rotations is the sum of the number of idling rotations and the number of reserved rotations.

[0012] Preferably, in S1, before the capping assembly grabs the cap, the servo motor is started to idle, and the output speed of the servo motor is controlled to increase to a first speed.

[0013] Preferably, in S2, when the output speed is switched from the first speed to the second speed, the output torque of the servo motor first decreases and then gradually recovers.

[0014] Preferably, when the output torque reaches a second torque threshold, the output speed gradually decreases until it reaches zero.

[0015] Preferably, the second rotation speed is less than or equal to 120 revolutions per minute.

[0016] Preferably, in S2, if the first speed is less than or equal to 240 rpm, when the output speed switches from the first speed to the second speed within the set time value, it is determined whether the output torque is lower than a set threshold value. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state.

[0017] Preferably, in S2, if the first speed is greater than 240 rpm, after the output speed is switched from the first speed to the second speed, it is determined whether the time value for the servo motor to drive the bottle cap to rotate at the second speed is greater than or equal to a preset time value. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state.

[0018] Preferably, the first rotation speed satisfies a preset relationship, which is:

[0019]

[0020] Wherein, v1 represents the first rotation speed, X represents the preset number of capping turns, T represents the preset capping time, T1 represents the time the servo motor runs at the first rotation speed, and T2 represents the preset time value.

[0021] On the other hand, the present invention also provides a servo capping machine, including a servo motor, a capping assembly and a controller connected to the servo motor and the capping assembly, wherein the servo motor is driven and connected to the capping assembly, and the controller controls the movement of the servo motor and the capping assembly according to the above-mentioned capping control method.

[0022] Beneficial effects of the present invention:

[0023] The capping control method proposed in the present invention can quickly complete most of the capping turns by first increasing the output speed of the servo motor to a higher first speed, thereby improving the efficiency of the capping. Secondly, when the output torque reaches the first torque threshold or the number of rotations reaches the preset number of turns, the speed is switched to the lower second speed and the output torque is increased at the same time. This staged control method effectively reduces the influence of the inertia moment of the transmission chain on the capping process. It avoids the capping assembly from continuing to cap after reaching the preset torque due to the inertia moment, thereby preventing the capping torque from continuously increasing beyond the allowable range of the capping torque, ensuring that the capping torque is within a suitable range, and ensuring the sealing of the seal, and making the capping torque within the acceptable range for the user. When the output torque reaches the second torque threshold, the servo motor is controlled to maintain the output torque at the second torque threshold, which can stabilize the final effect of the capping and further ensure the quality and reliability of the capping. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a curve diagram showing the relationship between output torque and time provided in the first embodiment of the present invention;

[0025] Figure 2 is a curve diagram showing the relationship between the output speed and time provided in the first embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of a servo capping machine provided in Embodiment 2 of the present invention;

[0027] Figure 4 It is a schematic diagram of the operation flow of the servo capping machine provided in the second embodiment of the present invention.

[0028] In the figure:

[0029] 1. Servo motor; 2. Capping head; 3. Capping head; 4. Capping support; 5. Lifting cam; 6. Gear set; 7. Capping arm; Q1. Translation section; Q2. Capping descending section; Q3. Capping translation section; Q4. Capping descending section; Q5. Capping section; Q6. Ascending section. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0034] Embodiment 1

[0035] See also Figure 1 and Figure 2 The capping control method provided by the embodiment of the present invention includes S1, starting the servo motor, and controlling the output speed of the servo motor to increase to a first speed, thereby driving the capping assembly to drive the bottle cap to rotate at the first speed; S2, detecting the output torque of the servo motor and the number of rotations of the bottle cap, when the output torque reaches the first torque threshold or the number of rotations reaches the preset number of rotations, controlling the output speed to switch from the first speed to the second speed, and controlling the output torque to increase; S3, when the output torque reaches the second torque threshold, controlling the servo motor to maintain the output torque at the second torque threshold.

[0036] The capping control method proposed in the present invention can quickly complete most of the capping turns by first increasing the output speed of the servo motor to a higher first speed, thereby improving the efficiency of the capping. Secondly, when the output torque reaches the first torque threshold or the number of rotations reaches the preset number of turns, the speed is switched to the lower second speed and the output torque is increased at the same time. This staged control method effectively reduces the influence of the inertia moment of the transmission chain on the capping process. It avoids the capping assembly from continuing to cap after reaching the preset torque due to the inertia moment, thereby preventing the capping torque from continuously increasing beyond the allowable range of the capping torque, ensuring that the capping torque is within a suitable range, and ensuring the sealing of the seal, and making the capping torque within the acceptable range for the user. When the output torque reaches the second torque threshold, the servo motor is controlled to maintain the output torque at the second torque threshold, which can stabilize the final effect of the capping and further ensure the quality and reliability of the capping.

[0037] The specific steps of the capping control method are described below.

[0038] S1, starting the servo motor, and controlling the output speed of the servo motor to increase to a first speed, thereby driving the capping assembly to drive the bottle cap to rotate at the first speed;

[0039] In S1, before the capping assembly grabs the cap, the servo motor is started to idle, and the output speed of the servo motor is controlled to increase to the first speed, shortening the time of the overall capping process, thereby further improving the efficiency of the capping. In addition, increasing the speed to the first speed in advance can respond more quickly to the subsequent cap grabbing and capping actions, reducing the time delay caused by the startup and acceleration process, making the entire capping process smoother and more efficient.

[0040] S2, detecting the output torque of the servo motor and the number of rotations of the bottle cap, and when the output torque reaches a first torque threshold or the number of rotations reaches a preset number of rotations, controlling the output speed to switch from the first speed to the second speed, and controlling the output torque to increase;

[0041] Among them, the output speed can be switched by judging the torque. When the torque reaches the first torque threshold, the output speed is controlled to switch from the first speed to the second speed. This switching method is controlled by the set torque. Each time the cap is screwed, the speed is switched after reaching the set first torque threshold. Therefore, the remaining tightening turns of each capping are very close, so the low-speed capping time is also close. Under the same production speed, by adjusting the size of the first torque threshold, the switching time point can be controlled, thereby controlling the size of the remaining tightening amount, achieving the control of the low-speed tightening time, and achieving the goal of high production capacity.

[0042] However, it is worth noting that this switching method is only suitable for bottles and caps with obvious torque changes during the capping process, such as bottles and caps with anti-theft rings; it is not applicable to bottles and caps that are tightened as the torque increases.

[0043] In addition, the output speed can also be switched by judging the rotation. When the number of rotations reaches the preset number of rotations, the output speed is controlled to switch from the first speed to the second speed. This switching method has no requirements for the matching of the bottle and the cap, and is suitable for the matching of all types of bottles and bottle caps.

[0044] In this switching method, due to the uncertainty of the thread alignment position, the starting point of the cap screwing may not be the starting point for screwing into the thread, and it is necessary to idle to the starting point of the thread insertion (the idle amount is determined according to the number of thread heads, and a single-head thread requires a maximum of 1 idle turn). As a result, the remaining tightening amount varies. It is necessary to ensure that the time required for the maximum remaining number of turns is used for low-speed tightening, where the number of turns is the sum of the idle turns and the reserved number of turns. The time required is relatively long, resulting in lower production capacity.

[0045] The present invention uses a first speed to quickly and quickly screw the capping cover for a certain number of turns, and then switches to a second speed to tighten the capping cover at a lower speed, thereby achieving Figure 1 and Figure 2 The curve change relationship in the capping drive chain is used to reduce the influence of the inertia moment of the capping transmission chain on the capping torque.

[0046] The first speed satisfies a preset relationship, which is:

[0047]

[0048] Wherein, v1 represents the first rotation speed, X represents the preset number of capping turns, T represents the preset capping time, T1 represents the time the servo motor runs at the first rotation speed, and T2 represents the preset time value.

[0049] The second speed is less than or equal to 120 rpm. Specifically, when the second speed is less than or equal to 80 rpm, the capping effect is the best (the fluctuation range of the opening torque is the smallest); when the second speed is greater than 80 rpm and less than or equal to 120 rpm, the fluctuation range of the opening torque is acceptable; and when the second speed is greater than 120 rpm, the opening torque fluctuates greatly and may exceed the limit range.

[0050] See also Figure 1 and Figure 2 During t3-t4, when the output speed switches from the first speed to the second speed, the output torque of the servo motor first decreases and then gradually recovers. When the output speed switches from the first speed to the second speed, the torque first decreases due to the decrease in speed, thereby avoiding damage to the screw cap assembly, bottle cap or bottle due to a sudden change in torque. After the speed stabilizes, the torque recovers and gradually increases, thereby ensuring the tightening force during the screw capping process.

[0051] In order to ensure the quality of screw capping, it is necessary to judge the torque abnormality. Specifically, in S2, if the first speed is less than or equal to 240 rpm, when the output speed switches from the first speed to the second speed within the set time value, it is judged whether the output torque is lower than the set threshold. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state. Figure 2 As shown, the time value is set to t3-t4.

[0052] If the first speed is greater than 240 rpm, after the output speed is switched from the first speed to the second speed, it is determined whether the time value during which the servo motor drives the bottle cap to rotate at the second speed is greater than or equal to the preset time value. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state. Figure 2 As shown, the preset time value is t4-t5.

[0053] S3, when the output torque reaches the second torque threshold, control the servo motor to maintain the output torque at the second torque threshold. And ensure that after the capping is completed, the torque is at the second torque threshold and maintained for the rated time, otherwise it will cause the torque to be too small. After that, the capping cycle is completed and the next cycle begins. Figure 1 As shown, the rated time is t5-t6.

[0054] like Figure 2 As shown in the figure, when the output torque reaches the second torque threshold, the output speed gradually decreases until it reaches zero. Among them, the t4-t5 section of the speed change curve is the guarantee of the maximum torque. If the output speed drops directly to 0 at point t4, the tightening torque is affected by the inertia moment, making the cover opening torque exceed the acceptable range.

[0055] As for the setting method of the first torque threshold and the second torque threshold, they can be set uniformly, that is, the first torque threshold is equal to the maximum torque of high-speed capping, the second torque threshold is equal to the maximum torque of capping, and the same first torque threshold and second torque threshold are set for any capping head. In this case, affected by the friction of the capping transmission chain, the switching torques of different capping heads are different, which can easily lead to undesirable phenomena such as high capping and excessive torque. In order to reduce or eliminate the influence of no-load friction, it is necessary to reduce the friction of the transmission chain, resulting in increased production costs.

[0056] The first torque threshold and the second torque threshold can also be set independently for each capping head. This method can compensate for the no-load friction of each capping transmission chain according to the different conditions, thereby reducing the requirements for the production accuracy of the transmission chain and reducing production costs. However, as the equipment operating time increases, the friction decreases and needs to be adjusted frequently.

[0057] In addition, a compensatory setting can also be used, that is, the first torque threshold is equal to the difference between the maximum torque of high-speed capping and the friction torque of the capping arm under no-load; and the second torque threshold is equal to the difference between the maximum torque of the capping and the friction torque of the capping arm under no-load, thereby avoiding the influence of the friction torque of the capping transmission chain on the torque threshold.

[0058] In actual operation, the required torque setting method is adaptively selected according to actual needs, and no limitation is made here.

[0059] Embodiment 2

[0060] The embodiment of the present invention further provides a servo capping machine, which includes a servo motor 1, a capping assembly and a controller (not shown), wherein the controller is connected to the servo motor 1 and the capping assembly, and the specific connection mode is a control connection. The servo motor 1 is drivingly connected to the capping assembly and is used to drive the capping assembly to rotate so that the capping assembly caps.

[0061] Specifically, Figure 3 As shown, the screw capping assembly includes a screw capping head 2 and a grasping capping head 3. The grasping capping head 3 is connected to the screw capping head 2 and is used for grasping the cap. When the screw capping head 2 rotates, the grasping capping head 3 is driven to rotate, thereby causing the grasping capping head 3 to grasp the bottle cap and rotate to connect the bottle cap to the bottle.

[0062] Optionally, the servo capping machine further comprises a capping support 4, a lifting cam 5, a gear set 6 and a capping arm 7. The lifting cam 5 is used to control the height position of the capping arm 7 at different circumferential angles; the servo motor 1 is used to output the capping torque and control the speed and torque of the capping arm 7. The gear set 6, the capping arm 7, the capping head 2 and the capping head 3 together constitute a capping transmission chain, which is used to transmit the torque and speed of the servo motor 1 to the capping head 3.

[0063] Specifically, the output end of the servo motor 1 is connected to the gear set 6, the gear set 6 is connected to the capping arm 7, and the capping head 2 is connected to the capping arm 7. The capping support 4 is used to support the capping arm 77 and to rotate around the cam structure with the capping arm 7 to grab the bottle caps on the bottle cap conveying line or to perform capping on different bottle conveying lines. The capping head 3 is used to grab the bottle caps and transmit the capping torque and rotation speed to the bottle caps.

[0064] The working principle of the servo capping machine provided in this embodiment is as follows:

[0065] The servo motor 1, gear set 6, capping arm 7, capping head 2, and capping head 3 form a capping transmission chain. The servo motor 1 directly drives the capping head 3 to rotate and perform capping. The capping support 4 is provided with rotational power by the support base, and rotates synchronously with the bottle transmission of the filling production line to ensure that each capping head 3 corresponds to a bottle. The lifting cam 5 has grooves of different heights on the circumference, and the bearing with shaft of the capping arm 7 moves in the groove; the lifting cam 5 is fixed by the support base. When the capping arm 7 rotates with the capping support 4, the lifting cam 5 controls the height of the capping arm 7 to perform different operations in different areas.

[0066] like Figure 4 As shown, the capping arm 7 rotates one circle and passes through the translation section Q1, the capping descending section Q2, the capping translation section Q3, the capping descending section Q4, the capping section Q5 and the ascending section Q6 in sequence. When the capping arm 7 is located in the capping descending section, the cap is grasped by the capping head 3. When the capping arm 7 is located in the capping section, the capping operation is performed.

[0067] It should be noted that the rotation direction of the capping support 4 can be changed according to the production line. The more specific working steps of the servo capping machine can be referred to the prior art, and this embodiment does not limit this.

[0068] The above embodiments are only to illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and modifications, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A capping control method for controlling a servo capping machine, wherein the servo capping machine comprises a servo motor and a capping assembly, wherein the servo motor is connected to the capping assembly and is used to drive the capping assembly to move, wherein: The capping control method comprises: S1, starting the servo motor and controlling the output speed of the servo motor to increase to a first speed, thereby driving the capping assembly to drive the bottle cap to rotate at the first speed; S2, detecting the output torque of the servo motor and the number of rotations of the bottle cap, and when the output torque reaches a first torque threshold or the number of rotations reaches a preset number of rotations, controlling the output speed to switch from the first speed to the second speed, and controlling the output torque to increase; S3. When the output torque reaches a second torque threshold, controlling the servo motor to maintain the output torque at the second torque threshold.

2. The capping control method according to claim 1, characterized in that: The number of rotations is the sum of the number of idling rotations and the number of reserved rotations.

3. The capping control method according to claim 1, characterized in that: In S1, before the capping assembly grabs the cap, the servo motor is started to idle, and the output speed of the servo motor is controlled to increase to a first speed.

4. The capping control method according to claim 1, characterized in that: In S2, when the output speed is switched from the first speed to the second speed, the output torque of the servo motor first decreases and then gradually recovers.

5. The capping control method according to claim 1, characterized in that: When the output torque reaches the second torque threshold, the output speed gradually decreases until it reaches zero.

6. The capping control method according to claim 1, characterized in that: The second rotation speed is less than or equal to 120 revolutions per minute.

7. The capping control method according to claim 1, characterized in that: In S2, if the first speed is less than or equal to 240 rpm, when the output speed switches from the first speed to the second speed within the set time value, it is determined whether the output torque is lower than the set threshold value. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state.

8. The capping control method according to claim 1, characterized in that: In S2, if the first speed is greater than 240 rpm, after the output speed is switched from the first speed to the second speed, it is determined whether the time value for the servo motor to drive the bottle cap to rotate at the second speed is greater than or equal to a preset time value. If so, it indicates that the bottle cap torque is normal; otherwise, the bottle cap torque is in an abnormal state.

9. The capping control method according to claim 8, characterized in that: The first rotation speed satisfies a preset relationship, which is: Wherein, v1 represents the first rotation speed, X represents the preset number of capping turns, T represents the preset capping time, T1 represents the time the servo motor runs at the first rotation speed, and T2 represents the preset time value.

10. Servo capping machine, characterized in that, The invention comprises a servo motor (1), a capping assembly and a controller connected to the servo motor (1) and the capping assembly, wherein the servo motor (1) is drivingly connected to the capping assembly, and the controller controls the movement of the servo motor (1) and the capping assembly according to the capping control method according to any one of claims 1 to 9.

Images