JPH0675630A - Controller for approach interval between travel carriages - Google Patents

Abstract

PURPOSE:To enable fine carriage approach distance control without using a servo amplifier by converting the forward/backward motion of a rod for detection which retracts on striking on a precedent carriage into rotary motion and outputting it as a detection signal from a rotary encoder, and adjusting the rotating speed of wheels. CONSTITUTION:When the detection rod 5 fitted to a front wheel of a following carriage strikes on the precedent carriage, the rod 5 retracts against the elastic force of a coiled spring and the straight part 6a of an endless rotary belt 6 below the rod 5 retracts by specific length through a coupling means 7. The retraction of the belt straight part 6a rotates the input rotary shaft 11 of the rotary encoder 10 coupled with a pulley 8 wound with the belt 6 by a specific angle to generate variation in the angle of rotation, which is digitally displayed as the detection signal of the precedent carriage and sent directly to a central sequence controller. The rotation of a motor is controlled on the basis of this signal in proportion to the distance between the carriages to maintain a state wherein the following carriage travels right behind the precedent carriage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mutual distance control apparatus for traveling carriages in a conveyor equipped with a self-propelled electric carriage used in, for example, an automobile production line.

[0002]

2. Description of the Related Art Conventionally, in a conveyor of a production line of an automobile or the like, a self-propelled electric trolley having electric wheels is loaded with a conveyed product such as an assembled intermediate product, and various parts are mounted. In the work line, in order to prevent collision between traveling vehicles, the approaching distance between traveling vehicles has been adjusted.

[0003]

Conventionally, a linear pulse sensor equipped with a magnet scale has been known as such an approaching distance control device for the traveling carriages. This is to detect the preceding truck by the Magnescale, measure the moving amount of the magnet of the scale at the time of detection, send the measured value as a pulse signal to the servo amplifier once, and the signal amplified by this amplifier is further centered. Send to the sequence control device, control the rotation speed of the wheel drive motor by the control signal issued based on this detection signal, adjust the rotation speed of the electric wheels, and adjust the approach distance with the preceding bogie. It was done.

However, this requires a linear pulse sensor equipped with a magnescale and a servo amplifier which amplifies the pulse signal emitted from the magnescale and sends it to the central sequence control device, which increases the equipment cost. However, the time required from the measurement by the magnescale to issuing the control signal is slightly longer, and there is a problem that the trolley approach distance cannot be finely adjusted.

The object of the present invention is to solve the above-mentioned problems of the prior art, and to send the detection signal of the preceding truck directly to the central sequence control device so as to issue the control signal to the truck drive device, and therefore to the prior art. It does not require such a servo amplifier, the equipment cost is low, and from the detection of the preceding bogie,
The time required to output a control signal to the wheel drive motor is extremely short, and it is possible to finely adjust the approach distance of the carriage, which in turn can improve the productivity of automobiles, etc. To try to serve.

[0006]

In order to achieve the above-mentioned object, the present invention is attached to the front end of a self-propelled electric carriage having electric wheels operated by a drive mechanism and is biased forward. The forward bogie detection rod, which is normally projected from the front end of the bogie and retracts when hitting the preceding bogie, a conversion mechanism for converting the forward / backward movement of the detection rod into a rotational movement, and the conversion mechanism. A rotary encoder having an input rotary shaft to which the rotational movement is transmitted in relation, and a control mechanism for adjusting the rotational speed of the electric wheel by operating the drive mechanism based on a detection signal from the rotary encoder are provided. The main point is a device for controlling the approach distance between traveling vehicles.

The rotary encoder displays a movement amount from the zero position of the object to be measured as a digital signal according to a change in the rotation angle of the input rotary shaft.

That is, in the rotary encoder, the zero position of the input rotary shaft is determined by incorporating the rotary encoder into the device, and the rotation angle with the zero position as the coordinate origin is always displayed by a digital signal. In a rotary encoder, a light emitting diode and a phototransistor are arranged via a disc (rotating plate) on which a pattern is written, and when the disc rotates, some of the light that has passed through the slit according to the pattern is transmitted and some is The light that is blocked and transmitted is converted into a current by a phototransistor, and is converted into a complete digital signal by a waveform shaping circuit.

Although the accuracy of the inter-vehicle distance depends on the resolution of the rotary encoder, it is normally required to have an accuracy of ± 1 ° (± 2 mm).

[0010]

According to the approach distance control device for the traveling carriages, the preceding carriage detecting rod attached to the front end of the self-propelled electric carriage is normally urged forward by the action of the elastic force of the coil spring or the like. When the rod hits the preceding bogie, the rod retreats against the elastic force of the coil spring or the like, but the forward / backward movement of the detection rod is converted into the rotational movement by the conversion mechanism. Then, the rotational movement is transmitted to the input rotary shaft of the rotary encoder, and this changes the rotation angle by the input rotary shaft, and this angle is displayed as a digital signal as a detection signal of the preceding truck. For example, specifically, as a conversion mechanism for converting the forward / backward movement of the preceding carriage detection rod into a rotation movement, an endless rotation belt having a linear portion arranged in parallel to the detection rod, and an endless rotation belt. A connecting means for connecting a required portion of a straight line portion of the detection rod to the detection rod, and a pulley around which one of the folded end portions of the endless rotating belt is wound are used.
The rotary input shaft of the rotary encoder is connected to the pivot of the pulley.

Therefore, in this case, the retreat distance of the detecting rod is converted into the rotational length of the belt, and the conversion amount becomes the change of the rotation angle by the input rotary shaft of the rotary encoder, which detects the preceding truck. The signal is displayed as a digital signal.

Then, this digital signal is sent directly to the central sequence control device, and based on this digital signal, the central sequence control device drives the carriage drive device (motor).
It is possible to quickly issue a control signal to the.

By doing so, it is possible to check a certain amount of retreat of the rod by the rotary encoder and to give a speed command to the motor, regardless of the speed of the trailing carriage, and in proportion to the inter-vehicle distance. As described above, the rotation of the motor is controlled, and the state in which the preceding bogie is properly attached can be maintained, and high accuracy of, for example, an error of ± 2 mm can be expected.

Moreover, when the preceding truck is detected, the detection signal can be directly sent to the central sequence control device to output the control signal without passing through the servo amplifier as in the prior art. Therefore, from the detection of the preceding truck, the wheel can be detected. The time required to output a control signal to the drive motor is very short, and it is possible to finely adjust the trolley approach distance, which in turn can improve the productivity of automobiles and the like.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. The drawings show a case where the present invention is applied to an automobile production line.

In this specification, the front means the traveling direction of the carriage, and the left and right mean the front.

First, in FIGS. 3 and 4, a self-propelled electric trolley (1) traveling along a guide rail (20) laid on a floor surface (F) has a substantially rectangular trolley body ( On the upper surface of (2), there is provided a carrier lift (31) on which a carrier (30) such as an automobile assembly intermediate part is placed and which can be raised and lowered by a driving means such as a hydraulic cylinder (not shown). There is a large work space (32) around the periphery of ().

A pair of front and rear wheels (3) rolling on a guide rail (20) are attached to a central portion of a lower surface of the bogie body (2) via a rotating plate (33) and a bracket (34). The front wheel (3) of the vehicle is equipped with a drive mechanism (4). Drive mechanism
(4) includes a general-purpose motor, speed reducer, and brake. In addition, a pair of left and right brackets (3
At the lower end of 4), horizontal anti-vibration rollers (35) (35) that contact the left and right side surfaces of the guide rail (20) are pivotally attached, and a total of 4 wheels are installed on both left and right sides of the front and rear wheels (3). The casters (36) are mounted on the lower surface of the bogie body (2) so as to be freely rotatable in a horizontal plane.

Although not shown, a self-propelled electric cart
At the front and rear ends of the bogie body (2) of (1), for example, the foot of the worker fits between the bogies (1) and (1) that are adjacent to each other in the low speed working zone of the conveyor line. A cushioning material made of foamed synthetic resin or synthetic rubber is attached so that there is no gap.

At the front end portion of each self-propelled electric carriage (1), there is provided an approaching distance control device for mutual traveling carriages according to the present invention.

1 and 2 showing the details of the approaching distance control device for the traveling carriages, the self-propelled electric carriage (1) is mounted on the hanging wall (2a) below the front end of the carriage body (2). Three brackets (15a) (15b) (15c) are attached to the left via a plate (14), and a rod for detecting the preceding carriage (5) is slidably and penetratingly held on them. . Of the three brackets, the front and center brackets (15a) (15b)
Has a built-in bearing, and the rear bracket (15c) contains a bush made of synthetic resin. Further, a stopper (16) having a Duracon cushioning material (23) on the front surface is provided on the rod (5) portion between the central bracket (15b) and the rear bracket (15c).
The coil spring (12) is interposed between the rod (5) and the rear bracket (15c) so as to cover the rod (5).
The coil spring (12) is urged forward by the coil spring (12) and is movable back and forth.

Further, between the front bracket (15a) and the central bracket (15b), there is a rod for detecting the leading carriage.
An endless rotating belt (6) having a straight line portion (6a) parallel to the (5) is arranged below the (5). A large number of claws (6c) are provided at predetermined intervals on the inner surface of the endless rotating belt (6), and the front and rear folded end portions (6) of the endless rotating belt (6) are
b) and (6b) are wound around pulleys (8) and (8) having teeth that engage with these claws (6c). Front and rear pulleys (8) (8)
Are rotatably attached to pivots (9) (9) held by bearing brackets (17) (17) via bearings, respectively.

The mounting plate (14) has two horizontal arms (19) (1
The rotary encoder mounting vertical plate (21) is provided via the rotary encoder (10), and the rotary encoder (10) is mounted on the vertical plate (21) with its input rotary shaft (11) facing the pulley (8). Has been. The pivot shaft (9) of the pulley (8) and the input rotary shaft (11) of the rotary encoder (10) are coaxial with each other and are connected to each other via a coupling mechanism (22).

Further, between the front bracket (15a) and the central bracket (15b), there is a rod for detecting the leading carriage.
The portion (5) and the required portion of the linear portion (6a) of the endless rotating belt (6) are connected to each other via a connecting means (7).

It should be noted that, as shown in FIGS. 3 and 4, the conveyed object elevating table (31) has a pair of left and right openable links (41) connected in an X shape by connecting pins (40). ) (42), and links (41) (42) on both left and right sides by inserting / removing the piston rod of the fluid pressure cylinder (not shown).
Is opened and closed centering around the connecting pin, and the lifting table (31) is moved up and down.

Adjacent carriage connecting mechanisms (43) are provided at both front and rear ends of the carriage main body (2). This adjacent bogie coupling mechanism (43) is a hook (44) pivotally attached to the lower surface of the end of the bogie body (2) so as to be horizontally swingable and having a hook-shaped tip, and a link mechanism for connecting the hook (44). It is composed of a fluid pressure cylinder that is operated via the above, and an engaging pin that engages with the hook-shaped tip of the hook (44) is provided at the rear end of the preceding bogie (1).
(45) is provided. Therefore, with the rear end of the leading carriage (1) and the front end of the trailing carriage (1) in contact with each other, the piston of the hydraulic cylinder of the connecting mechanism (43) of the trailing carriage (1) is By connecting the front and rear bogies (1) and (1) to each other by protruding the rod and engaging the hook-shaped tip of the hook (44) with the engagement pin (45) of the preceding bogie (1). be able to. It should be noted that such a connecting mechanism for adjacent trucks (43)
May be omitted.

A power supply rail (46) is laid at a predetermined interval on the left side of the guide rail (20) on the floor surface (F), while a power supply rail (46) is installed on the left side of the rear end of the carriage body (2). A current collector (47) is mounted for moving along the axis (46) and supplying electricity to the motor of the drive mechanism (4). Power Rail (46)
Is composed of a power supply rail main body (46a) having a substantially U-shaped cross section, and a power supply section (48) mounted inside the main body and having a distribution line.

The power supply section (48) is provided with a required number of AC power supply lines, signal transmission lines, and ground lines.

The self-propelled electric carriages (1) equipped with the above-mentioned goods lifts (31) can independently travel at a desired speed by driving the electric wheels (3).

Now, for example, the trailing carriage (1) having a high speed approaches the leading carriage (1) which is moving slowly in the low speed zone of the conveyor line, and the trailing carriage (1) approaches the front end of the trailing carriage (1). The attached leading truck detection rod (5) is the leading truck.
When it hits (1), the rod (5) retreats against the elastic force of the coil spring (12), and along with this, the linear portion (6a) of the endless rotating belt (6) below the rod (5). Is retracted by a predetermined length via the connecting means (7).

In this embodiment, the rotary encoder (10)
Is a so-called absolute type,
The movement amount from the zero position of the object to be measured is displayed by a digital signal by the change of the rotation angle of the input rotation shaft (11). When this rotary encoder (10) is installed in the device, the zero position of the input rotary shaft (11) is determined,
The rotation angle with the zero position as the coordinate origin is always displayed by a digital signal.

Belt straight portion of the endless rotating belt (6)
By retreating (6a), the rear folded end (6b) of the belt (6)
The rotary encoder (1) connected to the pivot (9) of the pulley (8) around which the
The input rotary shaft (11) of (0) is rotated by a predetermined angle, and the conversion amount of the receding distance of the belt linear portion (6a) becomes the change of the rotary angle by the input rotary shaft (11) of the rotary encoder (10). This is displayed as a digital signal as a detection signal of the preceding carriage (1), and a central sequence control device (not shown)
Be sent directly to. In the central sequence control device, a control signal to the truck drive device (motor) (4) is promptly issued based on this digital signal to give a speed command to the motor.

In this way, regardless of the speed of the trailing carriage (1), the rotary encoder (10) checks a certain amount of retreat of the rod (5) to give a speed command to the motor. The rotation of the motor is controlled so as to be proportional to the inter-vehicle distance, and the state in which the preceding bogie (1) is perfectly attached can be maintained.

The accuracy of the inter-vehicle distance between the traveling carriages (1) and (1) is
Although it depends on the resolution of the rotary encoder (10), an encoder having an accuracy of ± 1 ° (± 2 mm) is used in this embodiment.

Therefore, for example, the leading vehicle detection rod (5)
If the stroke is set to 40 mm and the correction value when the rod (5) is retracted 38 mm in length is set to 0, it can be expected to have an error of ± 2 mm without causing a rear-end collision, even if it makes contact when following. It is possible to finely adjust the trolley approach distance.

Moreover, when the preceding carriage (1) is detected, the detection digital signal can be directly sent to the central sequence control device to output the control signal without passing through the servo amplifier as in the conventional case, and thus the preceding carriage (1) The time required from the detection of 1) to the output of the control signal to the wheel drive motor is extremely short.

In the above embodiment, as a conversion mechanism for converting the forward / backward movement of the preceding truck detection rod (5) into the rotational movement, the straight line portion () arranged parallel to the detection rod (5) is used. 6a) having an endless rotating belt (6), a connecting means (7) for connecting a required portion of the straight part (6a) of the endless rotating belt (6) to the detection rod (5), and an endless rotating belt. (6) A pulley (8) around which one of the folded ends (6b) is wound is used, and the rotary shaft (9) of the rotary encoder (10) is connected to the input shaft of the pulley (8). The shaft (11) is connected, but as a conversion mechanism that changes the forward / backward movement of the preceding bogie detection rod (5) into rotational movement, other combinations of rack and pinion, the above endless rotating belt (6) It is also good to use a wire or the like instead of.

The self-propelled electric trolley (1) is equipped with 2
One of the wheels (3) is provided with a drive device (4) controlled by the approaching distance control device for the traveling carriages. An electric drive equipped with such a drive device (4) is provided. A plurality of wheels (3) may be attached to the carriage (1).

[0039]

As described above, the apparatus for controlling the approaching distance between traveling vehicles according to the present invention is biased forward and forward and backward at the front end of a self-propelled electric vehicle having electric wheels operated by a drive mechanism. A rotary body having a rod for detecting the leading carriage freely attached, a conversion mechanism for converting forward / backward movement of the detection rod into rotational motion, and an input rotary shaft for transmitting the rotational motion in relation to the conversion mechanism. An encoder and a control mechanism that adjusts the rotation speed of the electric wheels by operating the drive mechanism based on the detection signal from the rotary encoder are provided, and when the preceding truck detection rod hits the preceding truck, The rod retreats, the retreat distance of this rod is converted into rotary motion by the conversion mechanism, and the rotary motion is transmitted to the input rotary shaft of the rotary encoder related to this conversion mechanism. Then, the change in the rotation angle of the input rotary shaft is displayed as a detection signal of the preceding truck by a digital signal, and this is directly sent to the central sequence control device, and based on this digital signal, the central sequence control device drives the truck drive device (motor). Since the control signal to) is sent quickly, the conventional servo amplifier is not required, the equipment cost is low, and from the detection of the preceding bogie,
The time required until a control signal is output to the wheel drive motor is very short, and it is possible to finely adjust the trolley approach distance, and it is possible to improve the productivity of automobiles and the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway enlarged side view of an approach distance control device according to the present invention provided on a traveling vehicle.

FIG. 2 is an enlarged cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a rear view of the self-propelled electric cart.

FIG. 4 is a plan view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Self-propelled electric bogie 2 Bogie main body 3 Electric wheel 4 Driving mechanism 5 Leading bogie detection rod 6 Endless rotating belt 6a Straight part 6b Folding back end 7 Connecting means 8 Pulley 9 Axis 10 Rotary encoder 11 Input rotating shaft

Claims (1)

[Claims] 1. An electric wheel operated by a drive mechanism (4)
It is attached to the front end of the self-propelled electric bogie (1) having (3) and is urged forward so that it always protrudes from the front end of the bogie (1) and retracts when it hits the preceding bogie (1). The rod for detecting the leading bogie that can be moved forward and backward (5)
A conversion mechanism for converting the forward / backward movement of the detection rod (5) into rotational motion, and a rotary encoder (10) having an input rotary shaft (11) for transmitting rotational motion in relation to the conversion mechanism, Control of the approach distance between traveling vehicles, which is equipped with a control mechanism that adjusts the rotation speed of the electric wheels (3) by activating the drive mechanism (4) based on the detection signal from the rotary encoder (10). apparatus.