JPH0428671A - Delivery control method of winding cord in formation of transmission belt - Google Patents

Abstract

PURPOSE:To set tension of cord at a fixed level when the speed of cord is often changed over by controlling the speed of cord by the total of a speed signal value as a main signal and the product of the speed signal value and a displacement signal value both serving as a compensation signal. CONSTITUTION:A speed signal value A detected by a tacho-generator 6 is a positive value proportional to the speed of winding while a deviation signal value B by a potentiometer 4 which becomes a positive value when a weight 5 exceeds a reference point and a negative value when exceeds the same is proportional to displacement. Both values A, B are to be outputted to a delivery controller 8. The controller 8 sends the values, A, B to an analogue arithmetic unit at which calculation of AXB is carried out (S3). The result of AXB and the value A is added by an adder to have A+(AXB) (S4). The result of A+(AXB) is sent as the countermeasure (S5) for reverse rotation of a motor 2a to the motor 2a through a direction limiter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a control method for feeding out a cord so that the tension is constant when the cord is wound around a mold in advance to form a power transmission belt.

[Conventional technology] ■Cords embedded as reinforcing materials in power transmission belts such as belts and toothed (non-black) healds are inserted into molding molds while maintaining tension at a predetermined constant value prior to forming the belt. wrapped around the surface of the If the tension is out of a predetermined value, the power transmission belt, which is obtained by integrally molding a rubber band with the cord, will undergo non-standard expansion and contraction deformation in the circumferential direction.

In order to wrap the cord around the mold with a predetermined tension, as shown in Figure 2, the cord X that is fed out toward the rotating mold Z is wound around a pair of dancer pulleys 3, and one of the Weight 5 on 3a
Tension is often applied to cord X by connecting it. Since the distance between the pulleys 3a and 3b of the dancer pulley 3 can be freely changed, even if there is a period when the speed at which the cord X is fed out does not match the speed at which it is wound around the mold Z, the difference is smoothly absorbed. Since a weight 5 is connected to the dancer pulley 3 as shown in the figure, a tension is applied to the cord X based on the weight of the weight.

The above method of using a weight as a tension setting load makes it easier to apply a constant tension to the cord than the method of applying a load using a fluid pressure cylinder or diaphragm. This is because in the latter method, the load applied to the cord tends to change due to friction of sliding parts in the cylinder, etc. However, the drawback of the method using weights is that
If the vertical position of the weight is not stable due to a difference in the feeding speed and winding speed of the cord, the load, that is, the cord tension will change based on the acceleration of the weight.

Therefore, conventionally, a cord speed detector, a weight displacement detector, or the like is used to control the feeding speed of the cord to match the winding speed around the mold. In other words, in Fig. 2, the feeding speed by the cord feeding machine 2 is
The winding of the cord X detected by the speed detector (tachogenerator) 6 is adjusted based on the speed signal and the displacement signal of the weight 5 detected by the displacement detector (potentiometer) 4. In principle, the feeding speed of cord The above displacement signal value (B
) is used.

Conventionally, as a command signal to the cord feeding machine 2,
These two signal values A and B (including amplification by each constant)
A+B was used as the main signal and correction signal, respectively.

[Problems to be Solved by the Invention] A problem with the conventional cord payout control method of adjusting the cord payout speed according to the sum of the speed signal value A and the displacement signal value B is the magnitude (ratio) of each signal value. is not always maintained in a desired state, so accurate control may not be possible. In other words, when the speed of winding the cord around the mold is changed, the level of the speed signal value A (main signal) changes to a level equivalent to that of the displacement signal value B.
Since there is no change in the level of the (correction signal), the balance in handling of both signals deviates from the optimal state for control purposes. If the ratio between the main signal and the correction signal is inappropriate, it will take a long time to match the cord winding speed to the unwinding speed, which will increase the number of areas with inappropriate hood tension in the formed belt. become. Moreover, in the case of forming power transmission belts, when the size of the mold changes, the winding speed of the cord usually changes in proportion to the diameter, so this problem cannot be ignored.

The object of the present invention is to accurately adjust the winding speed of a cord, even when the speed is frequently changed, to quickly match the winding speed to the tension of the cord at a predetermined constant value. It is an object of the present invention to provide a cord payout control method that can perform the following functions.

[Means for Solving the Problems] In the method for controlling the winding and feeding out of the cord in power transmission belt forming according to the present invention, the cord to be wound around the mold is connected to the tension setting weight as described above. This method uses a dancer pulley around which a dancer is wound, a displacement detector for its weight, a speed detector for the cord, and a variable speed cord payout machine, and controls the dancer pulley to be let out at a constant rate, and the cord is let out by the cord payout machine. The speed of the cord is determined by using the speed signal value A (including a constant multiple of A) detected by the above-mentioned speed detector as the main signal, and the speed signal value A and the displacement detected by the above-mentioned displacement detector. The product of signal value B (including a constant multiple of B) is used as a correction signal, and adjustment is made according to the sum of both, ie, A+(AXB).

[Function] Like the conventional control method described above, the cord feeding control method of the present invention adjusts the feeding speed by the cord feeding machine using the cord speed signal value A and the weight displacement signal value B as a command signal. However, the signal value A which is the main signal
The product of signal values A-B is used as the correction signal to be added to. This product is the main signal (A) of the command signal and the correction signal (AXB
) and the winding ratio (the proportion of the command signal) is constant regardless of the speed. Therefore, once the ratio of the magnitudes of the main signal and correction signal is set to the optimal state,
For example, even if the winding speed of the cord is changed when the mold is replaced, the optimum ratio is maintained, and the winding speed is always quickly matched to the winding speed of the cord. When the cord feeding speed is quickly adjusted, the time required for the vertical position of the weight to stabilize and the cord tension to reach a predetermined constant value is shortened, so that the number of defective parts in the formed belt is reduced.

"Embodiment" FIG. 1 is a control system diagram showing the flow of signals in a cord feeding control method that is an embodiment of the present invention.
The figure is a conceptual diagram showing a mechanical device for feeding out a cord and winding it around a mold, which is used in this embodiment in the same manner as in the prior art. Note that the code X here is a reinforcing cord used as an interior material for the belt, and in this example, when forming the toothed power transmission belt material (the slab before being cut into rings to make the final product), This relates to the unwinding of cord X when winding the cord onto the surface of mold Z. The mold Z, which has grooves corresponding to the teeth of the belt formed on its surface, is covered with a canvas Y as shown in Figure 2, and then this cord X is wrapped around it. The rubber material is molded and vulcanized to create a belt material.

As already partially explained, the mechanical device shown in Fig. 2 is for feeding the cord X onto the rotating mold Z and winding it at a predetermined tension. 2, a dancer pulley 3, a mold drive device 7, etc. are the main equipment. The feeding machine 2 consists of a drive pulley 2b directly connected to a variable speed feeding motor 2a and the other idle pulley 2c, and a cord X is wound several times between both pulleys 2b and 2C. The mold drive device 7 includes a motor 7a and a reducer 7, each of which has a speed set for constant speed rotation and an acceleration for acceleration and deceleration.
b, and a touch pulley 7c that presses the cord X onto the mold Z and moves in the axial direction thereof. The dancer pulley 3 consists of a pair of two pulleys 3b whose position is fixed and a pulley 3a which can move up and down, and by changing the distance between the two, the winding of the cord X onto the mold Z is controlled. The difference between the speed and the feeding speed by the feeding machine 2 is absorbed. Since the pulley 3a is connected to the weight 5 as shown in the figure via the timing belt 5a and its support pulley 5b, tension is applied to the cord X. Since the cord X is wound three times between both pulleys 3a and 3b, the magnitude of the tension is determined by the weight of the weight 5 (more precisely, the weight of the pulley 3a and the frictional force of each part are also taken into consideration). Number of cords X between pulleys 3a and 3b (-
6). In addition, the symbol i in the figure indicates a freely rotatable idle pulley.

Further, in this device, as shown in the figure, a tacho generator 6 is provided as a speed detector for the code X, and a potentiometer 4 is provided as a detector for the displacement of the weight 5. This is because the feeding speed of the feeding machine 2 needs to match the speed of the cord X wound around the mold Z.
Further, it is preferable that the height of the weight 5, that is, the position of the pulley 3a, be stationary at a reference point (the center of the movable range).

In the tachogenerator 6, since the idle pulley 6a around which the cord X is wound is directly connected to its shaft, the speed of the cord X (in this example, the speed at constant speed reaches several hundred meters per minute) is ) is detected. One potentiometer 4 is connected to the shaft of the support pulley 5b, and detects the displacement of the pulley 3a and weight 5 from the reference point based on the rotational displacement of the shaft as the belt 5a is displaced.

The speed signal value (A
) is a positive value proportional to the winding speed, and the displacement signal value by potentiometer 4 (denoted as B) is a positive value when the weight 5 rises above the reference point, and a negative value when it falls from the reference point. The value is proportional to the amount of displacement, and both are output to the feeding control device 8 as a voltage signal.

Figure 1 shows the tachogenerator 6 and the potentiometer 4.
The flow of signals between the control device 8 and the feeding machine 2 is shown. The signal value A output from the tacho generator 6 (step St) and the signal value B from the potentiometer 4 (step S2) are each sent to the control device 8, and the control device 8 processes them to control the feeding machine 2. A speed adjustment command signal is issued to the motor 2a (step S6), and the feeding control method of this embodiment is characterized by the processing of the signal value by the control device 8. That is, the control device 8 first sends the signal value A and the signal value B to an internal analog multiplier (not shown) to calculate AXB (step S3), and then calculates AXB and the signal value A of step S1. A+(AXB) is calculated by adding them using an adder (not shown) (step S4). Then, as a measure to prevent the motor 2a from reversing, this calculated value is passed through a direction limiter (not shown) (step S5), and then sent to the motor 2a (step S6). As for the analog multipliers and adders, commercially available ones constructed by combining various known functional elements such as operational amplifiers can be used.

A calculated as above as a command signal to the motor 2a
+(AXB), the first term A is the main signal and represents the target speed signal value itself, and the second term AXB
is a correction signal for returning the weight 5 to the reference point. The reason for finding the correction signal in this way is that if the magnitude (ratio) of the correction signal to the main signal is inappropriate,
This is because the convergence of the weight 5 to the reference point may be delayed or hunting may occur. In other words, if the correction signal is AXB (or a constant multiple thereof) as in this embodiment, the ratio between the two will not change regardless of the magnitude of the main signal A, so the ratio is set to the optimal state. Then, even if the speed of code X changes, weight 5 always smoothly converges to the reference point.

In this respect, with the mechanical device shown in Figure 2, even if the die Z (diameter) changes depending on the size of the belt material to be formed, the winding process time can be made uniform. In order to simplify the control of the motor 7a, the operating speed of the drive device 7 is not changed, so the speed of the code X is switched according to the diameter of the mold Z.
It is extremely effective in If weight 5 does not converge well, code
The tension fluctuates over a long period of time, resulting in an increase in the number of parts of the heald material with poor cord tension (parts that need to be removed because the diameter or tooth pitch deviates from the specified values due to expansion and contraction deformation after molding). In this embodiment, although the weight 5 fluctuates slightly during acceleration and deceleration at the start and end of winding, and some defective parts are created only at both ends of the belt material, the weight 5 converges quickly. The amount of generation (width along the axial direction) in that area has been reduced to about half of the conventional amount.

[Effects of the Invention] The cord feeding control method according to the present invention has the following effects.

1) Even if the speed at which the cord is wound around the mold is changed, by always maintaining the optimal ratio of the main signal and correction signal,
The winding speed can be quickly matched with the unwinding speed to maintain the tension of the cord at a predetermined constant value, thereby reducing the number of defective parts in the formed belt.

2) Because of the above I), since there is no need to change the rotational speed of the cord for each mold diameter in order to keep the speed constant, the mold drive device can be configured simply, and the mold As long as the axial length (width of the belt material) is constant, winding can be done in the same amount of time.

3) In order to realize the present control method, for example, it is sufficient to add a multiplier to the conventional device, and only a small amount of cost is required.

[Brief explanation of drawings]

FIG. 1 is a control system diagram showing a signal flow in a cord feeding control method according to an embodiment of the present invention. FIG. 2 is a conceptual diagram showing a mechanical device that feeds out the cord and winds it around the mold. 2. Feeding machine, 3. Dancer pulley, 4. Potentiometer (displacement detector), 5. Weight, 6. Tacho generator (speed detector), 7. Mold drive device, 8... Feeding control device, X code, Z... Mold.

Claims (1)

[Claims] A dancer pulley in which a cord to be wound around a mold when forming a power transmission belt is connected to a tension setting weight, and around which the cord is wound, a displacement detector for the weight, a speed detector for the cord, and a method of controlling the cord to be fed out at a constant tension using a variable speed cord feeding machine, in which the speed of the cord fed out by the cord feeding machine is determined by using the speed signal value detected by the speed detector as the main signal. A method for controlling feeding out of a wrapped cord in forming a power transmission belt, characterized in that the product of the speed signal value and the displacement signal value detected by the displacement detector is used as a correction signal, and adjustment is made according to the sum of both.