Brake device wear detection device, injection molding machine using the same, and wear detection method
The brake device detects wear by analyzing torque profiles, eliminating the need for inductance detection circuits, thus reducing costs and enhancing wear detection efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- THE JAPAN STEEL WORKS LTD
- Filing Date
- 2022-11-09
- Publication Date
- 2026-06-30
AI Technical Summary
Existing brake device wear detection methods require a circuit for inductance detection, which increases costs.
A brake device with a rotating shaft, brake pad, electromagnet, control unit, and determination unit that determines wear based on the driving torque over a specific period, utilizing the torque profile changes due to brake pad wear.
Provides a cost-effective brake system wear detection method by analyzing torque changes to assess brake pad wear without the need for inductance detection circuits.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a wear detection device for a brake device, an injection molding machine using the same, and a wear detection method.
Background Art
[0002] Brake devices for braking the rotation of a rotating body are used in various fields. Patent Document 1 discloses a brake device used for a mold opening / closing motor of an injection molding machine. The brake device operates by pressing an iron brake plate against a rotating brake pad. When releasing the brake, an electric current is applied to a coil disposed opposite the brake plate, and the brake plate is pulled away from the brake pad by an electromagnetic force. Wear of the brake pad is detected by detecting the inductance of the coil.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the method for detecting wear of the brake device disclosed in Patent Document 1, a circuit for detecting the inductance of the coil is required. The present disclosure aims to provide a wear detection device for a brake device with lower cost.
Means for Solving the Problems
[0005] According to this disclosure, the brake device includes a rotating shaft driven by a drive unit, a brake pad rotatable with the rotating shaft, and an electromagnet that exerts a magnetic force on the braking plate of the brake pad in a direction away from the brake pad. The wear detection device includes a control unit and a determination unit. The control unit activates the drive unit for the rotating shaft and energizes the electromagnet, and the determination unit determines the wear of the brake pad based on the driving torque of the drive unit over a specific period of time. The drive torque T1 has an increasing section, a decreasing section following the increasing section, a re-increasing section following the decreasing section, and a steady-state section following the re-increasing section. A specific period is set to be a section of the decreasing section and the re-increasing section where the drive torque is lower than that of the steady-state section. [Effects of the Invention]
[0006] According to this disclosure, it is possible to provide a brake system wear detection device that is more cost-effective. [Brief explanation of the drawing]
[0007] [Figure 1] This is a schematic diagram of a vertical injection molding machine. [Figure 2] This is a schematic diagram of the motor used for switching between different types of switches. [Figure 3A] This is a magnified view of a portion of Figure 2, showing the operation of the braking system when de-energized. [Figure 3B] This is a magnified view of a portion of Figure 2, showing the operation of the braking system during excitation. [Figure 3C] This is a magnified view of a portion of Figure 2, showing the operation of the braking system when de-energized (during brake pad wear progression). [Figure 4] This is a flowchart showing the general steps of the brake device wear detection method according to this embodiment. [Figure 5A] This is a conceptual diagram showing the time variation of the speed command and actual speed of the movable panel, as well as the rotation speed of the opening and closing motor. [Figure 5B] This is a conceptual diagram showing the time variation of the drive torque of a switching motor. [Figure 6] This graph shows the relationship between the current flowing through the coil and the driving torque of the switchgear motor. [Modes for carrying out the invention]
[0008] (Outline configuration of vertical injection molding machine 1) First, as an example of equipment to which the brake device wear detection method of the present invention is applied, a vertical injection molding machine will be described. Figure 1 shows a schematic configuration of an exemplary vertical injection molding machine 1. The vertical injection molding machine 1 has a fixed platen 3 on which a fixed mold 2 is provided, an upper movable platen 5A on which a movable mold 4 is provided, and a lower movable platen 5B. The upper movable platen 5A and the lower movable platen 5B are sometimes collectively referred to as the movable platen 5. An injection device 7 is provided above the upper movable platen 5A. The fixed platen 3 is fixed to the housing 8 of the vertical injection molding machine 1. Multiple tie bars 9 slide vertically through the fixed platen 3. The upper movable platen 5A is fixed near the upper ends of the multiple tie bars 9, and the lower movable platen 5B is fixed near the lower ends of the multiple tie bars 9. Therefore, the movable platen 5 moves vertically as a single unit with respect to the fixed platen 3.
[0009] A toggle mechanism 10 is provided between the upper movable platen 5A and the lower movable platen 5B. The toggle mechanism 10 is driven by a ball screw mechanism 11. The ball nut 12 of the ball screw mechanism 11 is fixed to the crosshead 13 of the toggle mechanism 10, and the ball screw 14 engages with this ball nut 12. The ball screw 14 passes through the lower movable platen 5B, and its lower end is fixed to a large pulley 15 provided on the underside of the lower movable platen 5B. When the large pulley 15 is rotated, the ball screw 14 rotates. A mold opening / closing motor 16 is provided on the side of the lower movable platen 5B, and a drive pulley 17 is provided on the output shaft of the mold opening / closing motor 16. A timing belt 18 is wrapped between the drive pulley 17 and the large pulley 15.
[0010] When the mold opening / closing motor 16 is driven, the large pulley 15 and ball screw 14 rotate via the drive pulley 17 and timing belt 18. The rotation of the ball screw 14 causes the ball nut 12 and crosshead 13 to move up and down. In this way, the toggle mechanism 10 is driven, the movable platen 5 moves vertically, and the mold is opened and closed.
[0011] (Outline configuration of the mold opening / closing motor 16) Figure 2 shows the schematic configuration of the mold switching motor 16. The mold switching motor 16 has a rotor 31, a stator 32 consisting of coils, and a rotating shaft 33 connected to the rotor 31. The axial direction X of the rotating shaft 33 coincides with the vertical direction, so the upward direction in Figure 2 is the vertical upward direction, and the downward direction is the vertical downward direction.
[0012] The rotor 31 and stator 32 are housed in a housing 34. A gap is provided between the rotor 31 and the stator 32. A partition member 35 is fixed to the housing 34, and the rotating shaft 33 is rotatably supported by the housing 34 and the partition member 35 via bearings 36 and 37. A fan 38 is provided at the lower end of the rotating shaft 33 to cool the inside of the mold opening / closing motor 16. The mold opening / closing motor 16 is an example of a drive device for the movable platen 5, and a drive device other than a motor (e.g., a hydraulic system) can also be used.
[0013] (Outline configuration of the brake system 40) A brake device 40 is provided inside the mold opening / closing motor 16 to restrict the vertical movement of the movable platen 5 of the vertical injection molding machine 1. In other words, the mold opening / closing motor 16 is a so-called motor with a brake. The brake device 40 restricts the rotation of the mold opening / closing motor 16 and prevents the movable platen 5 from falling. The brake device 40 includes a fixing plate 41, a spacer 42, a brake pad 43, a braking plate 44, a plurality of springs 45 (only one spring 46 is shown in Figure 2), and a coil 46.
[0014] The fixing plate 41 is a disc-shaped member fixed to the spacer 42. The spacer 42 is a cylindrical member fixed to the partition member 35. Therefore, the fixing plate 41 is spaced apart from the partition member 35 and fixed to the partition member 35.
[0015] The boss 47 is fixed to the rotating shaft 33. A spline 48 is formed on the outer peripheral portion of the boss 47, and the brake pad 43 is attached to the spline 48. Therefore, the brake pad 43 is movable along the rotating shaft 33 and is also rotatable together with the rotating shaft 33. The brake pad 43 has a support member 43A and sliding portions 43B and 43C fixed to both surfaces of the support member 43A. It is also possible to omit the support member 43A and make the whole a sliding portion. In the following description, the sliding portions 43B and 43C may be referred to as the brake pad 43.
[0016] The brake plate 44 is provided between the partition member 35 and the brake pad 43 with respect to the axial direction X of the rotating shaft 33. The brake plate 44 is an iron disk and is provided so as to be movable along the rotating shaft 33 facing the brake pad 43. As will be described later, the brake plate 44 is supported in the vertical direction by the elastic force of the spring 45 and the electromagnetic force of the coil 46. The radial movement of the brake plate 44 is restricted by an appropriate method, and the brake plate 44 moves up and down while maintaining a concentric positional relationship with the rotating shaft 33. The brake plate 44 is not limited to being made of iron and can be formed of any material including a magnetic material.
[0017] The plurality of springs 45 are embedded in the partition member 35 at equal intervals in the circumferential direction. The spring 45 is a coil spring, but other types of springs such as leaf springs may be used, and more generally, any elastic body that generates an elastic repulsive force may be used. The spring 45 applies a pressing force downward in the vertical direction to the brake pad 43.
[0018] The coil 46 is embedded in the partition member 35. The coil 46 generates a magnetic field when a direct current is supplied. The coil 46 is an example of an electromagnet, and an electromagnet with other configurations can also be used. The coil 46 exerts a magnetic force on the brake plate 44 in a direction away from the brake pad 43 (upward in the vertical direction). The coil 46 has an annular shape, and its center substantially coincides with the center of the brake plate 44.
[0019] (Operation method of the brake device 40) Figures 3A and 3B are enlarged sections of Figure 2 showing the operation of the brake device 40. The brake device 40 is a type of de-excitation brake, where the brake operates when the coil 46 is not energized (de-excitation state) and is released when the coil 46 is energized (excitation state). Figure 3A shows the brake device 40 when the coil 46 is de-excitation, and Figure 3B shows the brake device 40 when the coil 46 is energized.
[0020] Referring to Figure 3A, since coil 46 is de-energized (unexcited), no electromagnetic force is generated by coil 46. When coil 46 is de-energized, spring 45 generates a pressing force that can press the braking plate 44 against the brake pad 43. Therefore, the brake pad 43 is pressed against the fixed plate 41 by spring 45. The brake pad 43 is pressed by both the fixed plate 41 and the braking plate 44 due to the pressing force of spring 45, and its rotation is restricted by friction. In other words, the brake is applied and the mold opening / closing motor 16 cannot rotate.
[0021] Referring to Figure 3B, the coil 46 generates an electromagnetic force when energized (excited). The electromagnetic force generated by the coil 46 attracts the brake plate 44 to the coil 46, and the brake pad 43 becomes non-contact with the fixed plate 41 and the brake plate 44. The brake pad 43 faces the fixed plate 41 with a small gap between them. The brake is released and the mold opening / closing motor 16 can rotate.
[0022] (Principle of wear detection method) As shown in Figure 3C, the brake pad 43 wears down with prolonged use, reducing its thickness. The thickness t2 of the brake pad 43 shown in Figure 3C is smaller than the thickness t1 of the brake pad 43 shown in Figure 3A. Even though the thickness of the brake pad 43 decreases, the spring 45 still generates enough pressure to press the brake plate 44 against the brake pad 43, so there is no significant impact on braking performance, but it is time to replace it.
[0023] On the other hand, when the thickness of the brake pad 43 decreases, the distance between the brake plate 44 and the coil 46 increases when the brakes are applied (i.e., when the brake plate 44 is pressing against the brake pad 43). As a result, the strength of the magnetic field applied from the coil 46 at the position of the brake plate 44 decreases. The force attracting the brake plate 44 decreases, and the time it takes for the brake plate 44 to separate from the brake pad 43 increases, thus worsening the response of the brake release operation. In this embodiment, this principle is used to detect wear of the brake device 40.
[0024] (Step 1 of the wear detection method) Referring to Figure 4, the steps of the wear detection method for the brake device 40 of this embodiment will be explained. In the following explanation of the wear detection method steps, Figure 2 will also be referred to as appropriate. The steps for opening a closed mold will be explained here, but the steps for closing an open mold can be performed in the same way. At the start of the process, the brake device 40 is in the state shown in Figure 3A. That is, the mold opening / closing motor 16 is stopped, and the coil 46 is de-energized (brake applied).
[0025] The following steps are performed by a control unit 19 that controls the drive of the mold opening / closing motor 16 and the energization of the coil 46, and a determination device 20 that determines the wear of the brake pad 43. In the following steps, a measuring device 21 for the drive torque of the mold opening / closing motor 16 (drive device) of the movable platen 5 and a monitoring device 22 for monitoring the rotational speed of the mold opening / closing motor 16 are also used. The control unit 19, determination device 20, measuring device 21 and monitoring device 22 constitute a wear detection device 23. The functions of the control unit 19 and determination device 20 are automatically executed by a computer according to a pre-programmed procedure. The measuring device 21 and monitoring device 22 are connected to the control unit 19 and determination device 20, and the outputs of the measuring device 21 and monitoring device 22 are transmitted to the measuring device 21 and monitoring device 22. The operation of the measuring device 21 and monitoring device 22 is controlled by the control unit 19. The following steps may also be performed manually by an operator.
[0026] Figure 5A shows the time variation between the speed command and the actual speed of the movable platen 5 when using new and worn brake pads 43. The figure also shows the time variation of the rotational speed of the mold opening / closing motor 16. Figure 5B shows the time variation of the drive torque of the mold opening / closing motor 16. The horizontal axis (time axis) is the same for both Figure 5A and Figure 5B.
[0027] First, the control unit 19 sends a speed command to the mold opening / closing motor 16, which is the drive device (step S1). The speed command specifies the speed change of the movable platen 5 when the brake is released, and in this example, it increases at a constant rate and then becomes a constant speed. However, the profile of the speed command is not limited in any way. The mold opening / closing motor 16 is started and controlled by this speed command. The speed command is common to both new and worn brake pads 43.
[0028] (Step 2 of the wear detection method) The mold opening / closing motor 16 is started and the coil 46 is energized at the same time (step S2). This process is performed by the control unit 19. The brake pad 43 is pressed against the braking plate 44 and the fixed plate 41, and its rotation is restricted by the frictional force generated between the braking plate 44 and the fixed plate 41. The mold opening / closing motor 16 continuously applies driving torque to rotate the brake pad 43. The driving torque increases according to the speed command, as shown in Figure 5B. When it reaches point A in Figures 5A and 5B, the driving torque overcomes the frictional force, and the brake pad 43 begins to rotate (begins to slide against the braking plate 44). Therefore, there is a slight time lag between energizing the coil 46 and the brake pad 43 beginning to rotate (or until the movable plate 5 begins to move).
[0029] This time lag is determined by the relationship between the drive torque of the mold opening / closing motor 16 and the frictional force. The frictional force is proportional to the elastic force of the spring 45. As shown in Figures 3A and 3C, the amount of expansion and contraction of the spring 45 differs between a new brake pad 43 and a worn brake pad 43, but the elastic force is almost constant and does not depend on the amount of expansion and contraction of the spring 45. Therefore, there is no significant difference in the time lag between a new brake pad 43 and a worn brake pad 43 (point A in Figure 5A). For similar reasons, there is no significant difference in the frictional torque of the mold opening / closing motor 16 when the brake pad 43 starts to rotate between a new brake pad 43 and a worn brake pad 43 (point C in Figure 5B).
[0030] Once the brake pad 43 begins to rotate, the frictional force changes from static friction to kinetic friction, causing the driving torque to begin to decrease. Subsequently, when the brake pad 43 completely separates from the brake plate 44, the frictional force is lost, and the driving torque decreases further. With a new brake pad 43, the gap between the brake plate 44 and the coil 46 is small, resulting in a large electromagnetic force acting on the brake plate 44. Therefore, the brake plate 44 is quickly attracted to the coil 46, and the brake pad 43 completely separates from the brake plate 44 in a short time after rotation begins. As a result, the driving torque decreases sharply, and as shown in Figure 5B, it drops to a minimum value at point B, then rises and transitions to a steady level.
[0031] In other words, as shown in Figure 5B, the drive torque of the mold switching motor 16 has an increasing section K1, a decreasing section K2 following the increasing section K1, a re-increasing section K3 following the decreasing section K2, and a steady-state section K4 following the re-increasing section K3.
[0032] In contrast, with a worn brake pad 43, the gap between the brake plate 44 and the coil 46 is large, resulting in a small electromagnetic force acting on the brake plate 44. Therefore, the brake plate 44 is attracted to the coil 46 more gradually, and the time it takes for the brake pad 43 to completely separate from the brake plate 44 is longer compared to a new brake pad 43. The drop in driving torque (minimum point) or the subsequent increase section K3 observed with a new brake pad 43 does not occur. In other words, the driving torque decreases gradually.
[0033] Therefore, a significant difference in driving torque occurs near point B between a new brake pad 43 and a worn brake pad 43. By measuring the driving torque near point B, the degree of wear of the brake pad 43 can be evaluated. The driving torque of the switch motor 16 is measured by the measuring device 21 under the control of the control unit 19.
[0034] (Step 3 of the wear detection method) Therefore, the detector 20, T1: Drive torque of the brake pad 43 subject to wear assessment over a specific period Ms: Threshold (tolerance) for wear amount of brake pad 43 Ts: Drive torque at threshold Ms In this case, if the drive torque T1 > drive torque Ts, it is determined that the wear amount of the brake pad 43 has exceeded the threshold Ms (step S3). Here, the threshold Ms is a guideline for when the brake pad 43 needs to be replaced, and is set in advance for each type of brake pad 43. The relationship between the threshold Ms and the drive torque Ts is measured in advance.
[0035] If the drive torque T1 > drive torque Ts, the judging device 20 issues an alarm (step S4) prompting the operator to inspect or replace the brake pads 43. If the drive torque T1 ≤ drive torque Ts, the judging device 20 issues a message indicating that the wear amount of the brake pads 43 is less than or equal to the threshold Ms.
[0036] In principle, the specific period should be the period during which the difference in driving torque between a new brake pad 43 and a worn brake pad 43 is maximum. However, the driving torque T1 of a worn brake pad 43 cannot be predicted in advance. Therefore, in practice, it is preferable to set the specific period to be near point B, where the driving torque of a new brake pad 43 is minimum, or to be in the vicinity of the minimum point where the driving torque is lower than that of the steady-state section K4. Specifically, the specific period is set to be in the section D between the decreasing section K2 and the re-increasing section K3, where the driving torque is lower than that of the steady-state section K4, and more preferably in the vicinity of the minimum point (point B) between the decreasing section K2 and the re-increasing section K3.
[0037] (Other wear detection methods) Referring to Figure 5A, in the period before the speed command for the movable platen 5 reaches a constant speed, the actual moving speed of the movable platen 5 increases initially with a new brake pad 43, then decreases, and then reaches a steady state. In contrast, with a worn brake pad 43, the actual moving speed of the movable platen 5 increases monotonically in the period before the speed command for the movable platen 5 reaches a constant speed. This is thought to be due to the same reason as the time change of the driving torque of the type opening / closing motor 16 shown in Figure 5B. Therefore, whether or not the actual moving speed of the movable platen 5 increases monotonically in the period before the speed command for the movable platen 5 reaches a constant speed can be used to determine the wear of the brake pad 43.
[0038] Specifically, the speed sensor 24 (see Figure 1) monitors the actual moving speed of the movable platen 5 before and after a specific period. The speed sensor 24 constitutes part of the wear detection device 23. If the actual moving speed of the movable platen 5 is increasing monotonically, the judge 20 can determine in step S3 that there is a high probability that the brake pad 43 is worn beyond the allowable limit. The alarm may be triggered when both driving torque T1 > driving torque Ts (condition 1) and the actual moving speed of the movable platen 5 is increasing monotonically (condition 2) are met simultaneously, or when either of these conditions is met. Since the speed sensor 24 of the movable platen 5 is required for this determination, the adoption of this determination method is optional, but its adoption can improve the accuracy of brake pad 43 wear detection.
[0039] Similarly, referring to Figure 5A, the rotational speed of the mold opening / closing motor 16 shows a trend that is almost the same as the actual moving speed of the movable platen 5. Therefore, whether or not the rotational speed of the mold opening / closing motor 16 of the movable platen 5 is increasing monotonically can be used to determine the wear of the brake pad 43. Specifically, the rotational speed of the mold opening / closing motor 16 is monitored before and after a specific period in the period before the speed command of the movable platen 5 reaches a constant speed. If the rotational speed of the mold opening / closing motor 16 is increasing monotonically, the determination device 20 can determine in step S3 that there is a high possibility that the brake pad 43 is worn beyond the allowable value. Monitoring of the rotational speed of the mold opening / closing motor 16 is performed by the monitoring device 22 under the control of the control unit 19.
[0040] (Operating modes of wear detection method) The above-described process is preferably performed in the normal mode of the brake device 40, that is, in a wear determination mode separate from the normal operation of the vertical injection molding machine 1. In other words, it is preferable that the control unit 19 and the determination device 20 operate only in a wear determination mode separate from the normal mode of the brake device 40. This makes it possible to avoid unnecessary wear of the brake pads 43. If the above-described process is performed in the normal mode of the brake device 40, it is preferable to perform it at intervals so as not to be performed excessively.
[0041] In the above embodiment, the timing of starting the mold opening / closing motor 16 and the timing of energizing the electromagnet coincide, but they may be different. For example, if the electromagnet is energized after starting the mold opening / closing motor 16, the time it takes for the brake pad 43 to completely separate from the braking plate 44 is delayed. In this case, the trend will be similar to that of a worn brake pad 43, but wear detection is possible if the same relationship as shown in Figure 5B is obtained. Conversely, if the electromagnet is energized before starting the mold opening / closing motor 16, the time it takes for the brake pad 43 to completely separate from the braking plate 44 is shortened. In this case as well, wear detection is possible if the same relationship as shown in Figure 5B is obtained.
[0042] (Example of verification of wear detection method) Using brake pads 43 with the same amount of wear, the drive torque of the mold opening / closing motor 16 was measured at the same timing (point B) by changing the amount of current supplied to the coil 46. Figure 6 shows the relationship between the amount of current supplied to the coil 46 and the drive torque of the mold opening / closing motor 16. As described above, when the brake pad 43 wears down, the strength of the magnetic field applied to the brake plate 44 decreases. Therefore, a large current simulates a state of small wear, and a small current simulates a state of large wear. It was confirmed that the drive torque of the mold opening / closing motor 16 changes according to the amount of current supplied to the coil 46, i.e., the amount of wear of the brake pad 43. The threshold Ts is appropriately determined according to the performance requirements of the vertical injection molding machine 1. The threshold Ts shown is an example and is not limited to it.
[0043] (Application to machines other than vertical injection molding machines) The above describes the wear detection method and wear detection device for the brake device 40 in the case of a vertical injection molding machine 1, but the present invention is not limited to a vertical injection molding machine 1. The present invention can also be applied to wear detection of the brake device of a horizontal injection molding machine. However, in the vertical injection molding machine 1, the movable platen 5 is held by the pressing force of the spring 45 when the coil 46 is not energized (de-energized), so the elastic force of the spring 45 is large, and the frictional force applied to the brake pad 43 is also large. For this reason, wear of the brake pad 43 progresses easily, and the effect of applying the present invention to a vertical injection molding machine 1 is significant. Furthermore, the present invention can also be applied to brake devices of machines other than injection molding machines.
[0044] (Note) This specification includes the following disclosures. [Configuration 1] The axis of rotation and A drive device for driving the aforementioned rotating shaft, A brake pad that is movable along the rotation axis and rotatable together with the rotation axis, A braking plate containing a magnetic material is provided, opposite to the brake pad, so as to be movable along the rotation axis, An electromagnet that exerts a magnetic force on the brake plate in a direction away from the brake pad, An elastic body that generates a pressing force capable of pressing the brake plate against the brake pad when the electromagnet is not energized, A brake pad wear detection device for a brake system having, It comprises a control unit and a determination unit, The control unit activates the drive device and energizes the electromagnet. The determination device is a wear detection device that determines the wear of the brake pads based on the drive torque T1 of the drive device during a specific period. [Configuration 2] The wear detection device according to configuration 1, wherein the determination device determines that the amount of wear of the brake pad exceeds a threshold Ms when the drive torque T1 > drive torque Ts (where Ts is the drive torque when the amount of wear of the brake pad is equal to the threshold Ms). [Configuration 3] The wear detection device according to configuration 1 or 2, wherein the control unit energizes the electromagnet at the same time as activating the drive device. [Structure 4] The wear detection device according to any one of configurations 1 to 3, wherein the control unit and the determination device operate in a wear determination mode different from the normal mode of the brake device. [Composition 5] The wear detection device according to any one of configurations 1 to 4, wherein the drive torque has an increasing section, a decreasing section following the increasing section, a re-increasing section following the decreasing section, and a steady-state section following the re-increasing section, and the specific period is set to a section of the decreasing section and the re-increasing section in which the drive torque is lower than the steady-state section. [Composition 6] The wear detection device according to configuration 5, wherein the aforementioned specific period is set near the minimum point between the decreasing section and the increasing section. [Composition 7] The wear detection device according to any one of configurations 1 to 6, wherein the drive device is a motor. [Structure 8] The device includes a monitoring device that monitors the rotational speed of the motor before and after the aforementioned specific period. The wear detection device according to configuration 7, wherein the determination device uses whether or not the rotational speed is monotonically increasing to determine wear of the brake pad. [Composition 9] An injection molding machine having a wear detection device according to any one of configurations 1 to 8, and the brake device. [Configuration 10] The aforementioned brake device is a brake device for the movable platen of the injection molding machine, as described in configuration 9 of the injection molding machine. [Composition 11] The device includes a monitoring device that monitors the movement speed of the movable platen before and after the aforementioned specific period. The injection molding machine according to configuration 10, wherein the determination device uses whether or not the moving speed is monotonically increasing to determine wear of the brake pad. [Composition 12] The injection molding machine is vertical, as described in any one of items 9 to 11. [Method 1] The axis of rotation and A drive device for driving the aforementioned rotating shaft, A brake pad that is movable along the rotation axis and rotatable together with the rotation axis, A braking plate containing a magnetic material is provided, opposite to the brake pad, so as to be movable along the rotation axis, An electromagnet that exerts a magnetic force on the brake plate in a direction away from the brake pad, An elastic body that generates a pressing force capable of pressing the brake plate against the brake pad when the electromagnet is not energized, A wear detection method for the brake pad of a brake device having the following steps: (a) Start the drive device (b) Energizing the electromagnet (c) Determining the wear of the brake pads based on the drive torque T1 of the drive device during a specific period. [Explanation of Symbols]
[0045] 1 Vertical injection molding machine 5 Movable plate Type 16 switching motor (an example of a drive device) 19 Control Unit 20 Judgment device 23 Wear detection device 33 Rotation axis 40 Brake system 43 Brake pads 44 Braking plate 45. Spring (an example of an elastic body) 46. Coil (an example of an electromagnet)
Claims
1. The axis of rotation and A drive device for driving the aforementioned rotating shaft, A brake pad that is movable along the rotation axis and rotatable together with the rotation axis, A braking plate containing a magnetic material is provided, opposite to the brake pad, so as to be movable along the rotation axis, An electromagnet that exerts a magnetic force on the brake plate in a direction away from the brake pad, An elastic body that generates a pressing force capable of pressing the brake plate against the brake pad when the electromagnet is not energized, A brake pad wear detection device for a brake system having, It comprises a control unit and a determination unit, The control unit activates the drive device and energizes the electromagnet. The determination device determines the wear of the brake pads based on the drive torque T1 of the drive device during a specific period. A wear detection device wherein the drive torque T1 has an increasing section, a decreasing section following the increasing section, a re-increasing section following the decreasing section, and a steady-state section following the re-increasing section, and the specific period is set to a section of the decreasing section and the re-increasing section in which the drive torque is lower than the steady-state section.
2. The wear detection device according to claim 1, wherein the determination device determines that the amount of wear of the brake pad exceeds a threshold Ms when the drive torque T1 > drive torque Ts (where Ts is the drive torque when the amount of wear of the brake pad is equal to the threshold Ms).
3. The wear detection device according to claim 1 or 2, wherein the control unit energizes the electromagnet at the same time as activating the drive device.
4. The wear detection device according to claim 1 or 2, wherein the control unit and the determination device operate in a wear determination mode separate from the normal mode of the brake device.
5. The wear detection device according to claim 1 or 2, wherein the specific period is set near the minimum point between the decreasing period and the increasing period.
6. The wear detection device according to claim 1 or 2, wherein the drive device is a motor.
7. The device includes a monitoring device that monitors the rotational speed of the motor before and after the aforementioned specific period. The wear detection device according to claim 6, wherein the determination device uses whether or not the rotational speed is increasing monotonically to determine wear of the brake pad.
8. An injection molding machine having a wear detection device according to claim 1 or 2, and the brake device.
9. The injection molding machine according to claim 8, wherein the brake device is a brake device for the movable platen of the injection molding machine.
10. The device includes a monitoring device that monitors the movement speed of the movable platen before and after the aforementioned specific period. The injection molding machine according to claim 9, wherein the determination device uses whether or not the moving speed is monotonically increasing to determine wear of the brake pad.
11. The injection molding machine according to claim 8, wherein the injection molding machine is of the vertical type.
12. The axis of rotation and A drive device for driving the aforementioned rotating shaft, A brake pad that is movable along the rotation axis and rotatable together with the rotation axis, A braking plate containing a magnetic material is provided, opposite to the brake pad, so as to be movable along the rotation axis, An electromagnet that exerts a magnetic force on the brake plate in a direction away from the brake pad, An elastic body that generates a pressing force capable of pressing the brake plate against the brake pad when the electromagnet is not energized, A method for detecting wear of the brake pads of a brake device having the following characteristics: (a) Start the drive device (b) Energizing the electromagnet (c) Determining the wear of the brake pads based on the drive torque T1 of the drive device during a specific period. A wear detection method comprising: the drive torque T1 having an increasing section, a decreasing section following the increasing section, a re-increasing section following the decreasing section, and a steady-state section following the re-increasing section, wherein the specific period is set to a section of the decreasing section and the re-increasing section in which the drive torque is lower than the steady-state section.