JP2019188566A - Spiral conveyor - Google Patents

Abstract

To provide a spiral conveyor capable of improving power-saving and vibration damping/silent sound effect, and improved so as to smoothly deal with clogging of chips or occurrence of contamination of foreign materials.SOLUTION: A spiral conveyor 10 includes: a thrust bearing 19 arranged around a knuckle 14 for driving a conveyance spiral 16; a strain gauge 23 for detecting a strain amount in the axial direction of the thrust bearing during conveyance of chips; and a controller 25 automatically controlling the drive (rotational speed, rotation/stopping, normal rotation/reverse rotation) of a motor on the basis of the detection amount. The controller controls so as to contribute to power-saving and vibration damping/silent sound by lowering the rotational speed of the motor when chips are not charged or an input is small, and to previously prevent of breakages of a motor output shaft and the bearing by emergency stop of the motor when clogging occurs during conveyance of chips.SELECTED DRAWING: Figure 4

Description

The present invention relates to a spiral conveyor for conveying chips and the like generated by metal cutting.

As shown in Patent Document 1, Non-Patent Document 1, and FIG. 1, the spiral conveyor 1 rotates the coil spring-shaped conveying spiral 3 accommodated in the tray 2 at a low speed in a predetermined direction by a motor 4 with a speed reducer. 2, the chips 5 fed into the tray 2 are conveyed in a predetermined direction in the tray 2 while being separated into solid and liquid, and discharged to a discharge duct 6 connected to the outlet of the tray 2. The cutting fluid 7 put into the tray 2 together with the chips 5 is gravity-dropped from the tray 2 in the middle of conveyance, is separated from the chips, and is collected in a cutting fluid tank 8 provided below.

Spiral conveyors with such a structure can be smoothly transported without any entanglement of chips even in a wide variety of shapes, sizes and materials, from long chain continuous chips that have expanded greatly to needle-shaped fine chips. It is simple and can be manufactured and provided at low cost, and it is possible to transport chips for a long distance in a machining system that connects many and many machine tools, and it can efficiently separate and collect cutting fluid adhering to the chips. It has been adopted by many machine tools.

JP-A-2018-001400

http://www.to-hatsu.co.jp/products/sc_built.html

In conventional spiral conveyors, the conveyor spiral is generally driven by rotating the motor at a constant speed (normal operation), but normal operation is performed even when chips are not inserted or when the input amount is small. Therefore, power consumption is wasted, and vibration and noise during normal operation are always generated.

Further, although it is a spiral conveyor that is less likely to be clogged due to its structure, clogging may occur depending on the amount and shape of chips introduced, or clogging may also occur due to foreign matters mixed in. If the normal operation is continued even when such a conveyance abnormality occurs, the motor output shaft and the bearing may be damaged.

As a solution to this problem, the current value flowing through the motor is measured using a thermal relay, shock relay, etc., and when an overcurrent (overload) is detected, an alarm is sounded and control is automatically performed to stop. However, the thermal relay is intended to prevent the motor from being burned out. The reaction is slow and the drive system may be damaged before stopping. Shock relays are fast but very expensive, and are practically difficult to use for spiral conveyors. In addition, since the control to detect the overcurrent and stop the motor does not work at all during normal operation, waste of power consumption due to normal operation being performed even when chips are not inserted or when the input amount is small. The above-mentioned problems of vibration and noise during normal operation cannot be solved.

Therefore, in view of the above-mentioned background, the problem to be solved by the present invention can improve power saving and vibration suppression and noise reduction effect of the conveyor, and when clogging of chips and mixing of foreign matters occur It is another object of the present invention to provide an improved spiral conveyor so that it can be smoothly handled.

In order to solve this problem, the present invention according to claim 1 is configured such that, by rotating a coil spring-shaped conveying spiral housed in a tray at a low speed in a predetermined direction by a motor, chips thrown into the tray are moved in a predetermined direction in the tray. In a spiral conveyor configured to convey a thrust, a thrust bearing which is disposed around a rotating body connected to a motor and rotates integrally and receives a thrust load, and a thrust which detects a thrust load received by the thrust bearing during chip conveyance It is characterized by having a load detection means and a control means for automatically controlling the driving of the motor (rotation speed, rotation / stop, forward / reverse rotation, etc.) according to the detection result by the thrust load detection means.

The present invention according to claim 2 is the spiral conveyor according to claim 1, wherein the thrust load detecting means is a strain gauge for detecting an axial strain amount of a thrust bearing.

According to a third aspect of the present invention, in the spiral conveyor according to the second aspect, the control means amplifies the amount of axial strain detected by the strain gauge, and chips at that time based on the output from the amplifier. It is characterized by having a controller that performs arithmetic processing to control the motor according to the conveyance state, and an inverter that outputs a drive signal to the motor based on the output from the controller.

According to a fourth aspect of the present invention, in the spiral conveyor according to the second or third aspect, the control means rotates the motor when the amount of axial strain detected by the strain gauge is equal to or less than a first threshold value. Control is performed to reduce the speed.

According to a fifth aspect of the present invention, there is provided the spiral conveyor according to any one of the first to fourth aspects, wherein the control means is configured to operate the motor when the amount of axial strain detected by the strain gauge is equal to or greater than a second threshold value. Is controlled so as to make an emergency stop.

According to a sixth aspect of the present invention, in the spiral conveyor according to the fifth aspect, the control means repeats several cycles of reverse rotation and forward rotation after emergency stop of the motor to detect axial strain detected by the strain gauge. Control is made so that the normal operation of the motor is resumed when the amount falls below or below the third threshold.

According to the first aspect of the present invention, since the chip conveyance state at that time is accurately grasped or estimated based on the detection result by the thrust load detecting means, the motor is appropriately driven and controlled according to the chip conveyance state. be able to.

According to the second aspect of the present invention, the strain gauge for detecting the axial strain amount of the thrust bearing is used as the thrust load detecting means for detecting that the thrust bearing has received the thrust load during chip conveyance. Thrust load can be detected with high accuracy without complicating and increasing the size of the conveyor.

According to the third aspect of the present invention, there is provided a preferred configuration example as a control means for automatically controlling the rotation speed and rotation / stop of the motor according to the detection result by the thrust load detection means, and the thrust load detection means is provided. The motor can be automatically controlled with high accuracy according to the detected thrust load (the amount of axial strain detected by the strain gauge).

According to the fourth aspect of the present invention, when the amount of axial strain detected by the strain gauge is excessively small, it is determined that the chip is not yet input into the spiral conveyor or the amount of input of the chip is excessive. Therefore, in this case, it is possible to control the motor rotation speed to be lower than the rotation speed at the time of normal operation, thereby improving power saving and vibration suppression / silent effect.

According to the present invention according to claim 5, when the amount of axial strain detected by the strain gauge is excessive, it is determined that clogging has occurred due to entanglement of the chips in the tray of the spiral conveyor, etc. In this case, it is possible to prevent the motor output shaft and the bearing from being damaged by controlling the motor to perform an emergency stop.

According to the present invention of claim 6, in the above case, when the axial strain amount detected by the strain gauge decreases to a normal value as a result of repeated reverse rotation and forward rotation of several cycles after the motor emergency stop. Since it is determined that the entanglement of chips has been eliminated, in this case, it is possible to increase the operating efficiency of the spiral conveyor by performing control to automatically resume the normal operation of the motor.

It is a front view which shows the basic structure of a spiral conveyor. It is principal part sectional drawing of the spiral conveyor by one Embodiment of this invention. It is an A section enlarged view in Drawing 2 at the time of motor non-drive (at the time of chip non-conveyance). It is an A section enlarged view at the time of motor drive (at the time of chip conveyance). It is the A section enlarged view equivalent to FIG. 3 of the conventional spiral conveyor.

A spiral conveyor according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. This spiral conveyor 10 has the same basic structure as the spiral conveyor 1 of FIG. 1, and its basic operation or action is the same as that already described with reference to FIG. 1, but it detects the thrust load during chip conveyance. Thrust load detection means, and control means for automatically controlling the rotation speed and rotation / stop of the motor according to the detection result by the thrust load detection means.

More specifically, the output shaft 13 of the motor 12 (the motor 4 in FIG. 1) provided with the speed reducer 11 is welded to the start end portion of the transport spiral 15 (the transport spiral 3 in FIG. 1) via the knuckle 14. It is connected to a fixed drive sleeve 16, and the conveying spiral 15 is rotated at a speed synchronized with the rotation speed of the motor output shaft 13 to convey the chips 5 in the tray 2 in the right direction in the figure.

When the motor 12 is driven and the chips 5 are conveyed by the conveying spiral 15, the motor output shaft 13 and the knuckle 14 that is connected to rotate together with the motor output shaft 13 have the mass of the conveying spiral 15 and the inserted chips 5. Since a radial load corresponding to the mass or the like (a load acting in the radial direction with respect to the shaft center) is applied, as shown in FIG. 5, in the conventional spiral conveyor 10 ′, the radial bearing 18, In the spiral conveyor 10 according to the embodiment of the present invention, a thrust bearing 19 that receives a thrust load acting on the knuckle 14 (also referred to as an axial load or an axial load) is mounted together with the radial bearing 18. Yes.

In FIG. 2, reference numeral 17 denotes a bearing case that houses the bearings 18 and 19. In FIG. 3, reference numeral 20 indicates an oil seal fixed in the bearing case 17 in order to prevent the cutting fluid 7 from leaking between the knuckle 14 and the bearing case 17, and reference numeral 22 indicates the inside of the bearing case 17. Reference numeral 28 denotes a fixed ring fixed to the outer surface of the knuckle 14, and reference numeral 29 denotes a spacer disposed between the bearings 18 and 19.

As is well known, the thrust bearing 19 is constituted by a rolling element 19c sandwiched between a pair of holding plates 19a, 19b. In this embodiment, the side surface of the one holding plate 19a (the fixed ring 22, 28), a strain gauge 23 is disposed or adhered to the surface. The strain gauge 23 is a sensor that measures the amount of strain by detecting a resistance change that occurs when the metal resistor is expanded and contracted by an external force. In the spiral conveyor 10, the transport spiral 15 is caused by a reaction force X during chip transport. When a thrust load is applied to the knuckle 14 and the thrust bearing 19 is deformed (compressed in the axial direction) (FIG. 3) (FIG. 3), the strain (displacement amount) generated in the axial direction of the knuckle 14 is detected by detecting the change in resistance. Used to measure D). That is, in the spiral conveyor 10, the “thrust load detecting means” of the present invention is configured mainly by the strain gauge 23.

That is, when there is no thrust load, the radial bearing 18 and the thrust bearing 19 are sandwiched between the oil seal 20 and the fixed rings 22 and 28 and are positioned in the axial direction. When the thrust load is applied, the knuckle 14 moves to the left in FIG. At this time, the outer end of the holding plate 19a of the thrust bearing 19 is restricted in movement by the fixed ring 22 of the bearing case 17, but the inner end moves in the same direction together with the knuckle 14 and the fixed ring 28 fixed to the knuckle. As shown in FIG. 4, the holding plate 19a is deformed obliquely, and accordingly, the strain gauge 23 attached to the holding plate 19a is also distorted. Since the holding plates 19a and 19b of the thrust bearing 19 extend in a direction perpendicular to the axial direction with the rolling element 19c interposed therebetween, the region exposed between the fixed rings 22 and 28 on the side surface of the holding plate 19a is utilized. A film-like strain gauge 23 can be attached.

Since the resistance change detected by the strain gauge 23 is a minute voltage change in units of micro V, the amplifier 24 amplifies the change to several thousand to several tens of thousands times and outputs it to the controller 25. The controller 25 controls the rotational speed of the motor 12 (and hence the rotational speed of the motor output shaft 13 after being decelerated by the speed reducer 11) in accordance with the voltage change amount amplified by the amplifier 24 (zero rotational speed, that is, the motor). 12 is stopped) and the result is output to the inverter 26. The inverter 26 converts this into a drive signal having a predetermined frequency and outputs it to a drive power supply (not shown) in the terminal box 27. Thus, the motor 12 is driven at a controlled rotational speed by the driving power source. That is, in the spiral conveyor 10, the “control means” of the present invention is configured so as to have the amplifier 25 and the inverter 26 with the controller 25 as a main component.

The axial displacement amount D detected by the strain gauge 23 is zero when the motor is not driven or when chips are not conveyed (FIG. 3), and the amount of chips 5 input when the motor is driven or when chips are conveyed (FIG. 4). Increase or decrease depending on As an example of specific control by the controller 25, when the axial displacement amount D is D ≦ Da or D <Da (Da is a minute threshold), the device is in operation (the motor 12 is in normal operation). This means that the chip 5 has not been thrown in or the amount of the chip 5 to be thrown in is minute, so that the controller 25 reduces the rotational speed of the motor 12 from that during normal operation. To control. Thereby, waste of power consumption can be eliminated, and vibration suppression and noise reduction effects can be enhanced.

As another example of the specific control by the controller 26, if the amount of chips 5 is excessive or the long chips 5 are entangled with the conveying spiral 15 and the conveying spiral 15 is clogged with the chips 5. Since the strain gauge 23 detects an axial displacement amount D (D ≧ Db or D> Db) that is greater than or equal to the large emergency stop threshold value Db, the controller 25 performs control to automatically stop the motor 12. Thereby, even when a conveyance abnormality occurs, it is possible to prevent the motor output shaft 13 and the bearings 18 and 19 from being damaged. In this case, it is preferable to promote an operation for eliminating the clogging by sounding an alarm.

Furthermore, after performing the control to automatically stop the motor 12 in the above case, the controller 26 repeats reverse rotation and forward rotation of several cycles, so that the strain gauge 23 is reduced to the normal operation return threshold value Dc or less. When this is detected (D ≦ Dc or D <Dc, Dc <Db), it is determined that the clogging of the chips has been eliminated, so that the motor 12 is re-driven to rotate at the rotation speed during normal operation. It can be performed.

Although the present invention has been described in detail above based on the illustrated embodiments, the present invention is not limited to this, and various modifications or changes can be made within the scope of the invention determined based on the description of the claims. It can be changed and implemented. For example, the spiral conveyor 10 of the illustrated embodiment is of a type having a hollow conveying spiral 15 having no central axis, but the present invention is also applicable to a type of spiral conveyor having a conveying spiral 16 having a central axis. Is possible. Moreover, although the spiral conveyor 10 shown in FIG. 1 connects the carrying-out duct 6 to the exit of the tray 10 and moves chips diagonally upward, the spiral conveyor without such a lift-up duct is also used. The present invention is applicable.

DESCRIPTION OF SYMBOLS 1 Spiral conveyor 2 Tray 3 Conveying spiral 4 Motor 5 with speed reducer 6 Chip 6 Discharge duct 7 Cutting fluid 8 Cutting fluid tank 10 Spiral conveyor 11 Reducer 12 Motor 13 Motor output shaft 14 Knuckle (rotating body)
15 Transport spiral 16 Drive sleeve 17 Bearing case 18 Radial bearing 19 Thrust bearing 20 Oil seal 21 Cover 22 Fixed ring (fixed to bearing case 17)
23 Strain gauge (Thrust load detection means)
24 Amplifier (control means)
25 Controller (control means)
26 Inverter (control means)
27 Terminal box 28 Fixed ring (fixed to the outer surface of the knuckle 14)
29 Spacer

Claims (6)

In a spiral conveyor configured to convey the chips thrown into the tray in a predetermined direction by rotating the coil spring-shaped conveying spiral housed in the tray in a predetermined direction by a motor at a low speed, the spiral is connected to the motor. A thrust bearing that is arranged around a rotating body that rotates integrally, receives a thrust load, a thrust load detection means that detects a thrust load received by the thrust bearing during chip conveyance, and a motor according to a detection result by the thrust load detection means And a control means for automatically controlling the driving. The spiral conveyor according to claim 1, wherein the thrust load detecting means is a strain gauge for detecting an axial strain amount of a thrust bearing. An amplifier that amplifies the amount of axial strain detected by the strain gauge; a controller that performs arithmetic processing based on an output from the amplifier to control the motor in accordance with a chip conveyance state at that time; and The spiral conveyor according to claim 2, further comprising an inverter that outputs a drive signal to the motor based on an output from the motor. 4. The control unit according to claim 2, wherein when the axial strain amount detected by the strain gauge is equal to or less than a first threshold value, the control unit performs control so as to decrease a rotation speed of the motor. Spiral conveyor. 5. The control unit according to claim 2, wherein the control unit controls the motor to make an emergency stop when an axial strain amount detected by the strain gauge is greater than or equal to a second threshold value. The spiral conveyor described. After the emergency stop of the motor, the control means repeats several cycles of reverse rotation and forward rotation, and when the amount of axial strain detected by the strain gauge falls below or below the third threshold, 6. The spiral conveyor according to claim 5, wherein control is performed so that the operation is resumed.