JPH01186464A - Freight loading platform - Google Patents

Abstract

PURPOSE:To permit the positioning with high precision by using the small-sized and lightweight device by installing a turning platform which is turnable around a vertical axis and two shifting boards which can shift in two directions on a horizontal plane, onto a freight loading platform and carrying out positioning in three directions by a driving part 4 using eccentric cams. CONSTITUTION:A freight loading platform 4 installed in the upper part of the machine body 1 of a transport vehicle is supported through the positioning means 5 (5x, 5y, 5theta) for three directions of the advance direction of the machine body installed at the center part of the freight loading platform 4, direction crossing at right angles with the advance direction, and the revolution direction around the vertical axis of the machine body 1. Each positioning means 5 is constituted so that the first and second shifting platform 50x and 50y and a turning platform 50theta are shifted and turned by the turning movements of the ball bearings 63x, 63y, and 63theta as eccentric cams for the eccentric shafts 62x, 62y, and 62theta connected through the flexible joints 61x, 61y, and 61theta onto the rotary shafts of the stepping motors 66y and 66theta in the driving parts 6x, 6y, and 6theta. Then, the fright loading platform 4 is mounted into the upper part of the second shift platform 50y.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a loading platform for a conveyance vehicle that automatically travels in a workplace, and more specifically, in two directions in a horizontal plane and in three directions of rotation around a vertical axis. The present invention relates to a loading platform with a directional positioning device.

[Prior art]

Transport vehicles, especially automated guided vehicles, have made significant progress over the past few years as core equipment in factory automation.

A conventional automatic guided vehicle has a loading platform on its upper surface for placing an article to be transported, and transports the article to a station provided in each process. Then, the article is automatically transferred from the automatic guided vehicle to each station by a transfer device provided at the station.

On the other hand, the stopping accuracy of an unmanned guided vehicle is about ±Iotm in the direction of movement and the direction crossing it, and about ±1° in the rotation direction around the vertical axis, and the Since the relative stopping position accuracy depends on the stopping accuracy of the automatic guided vehicle, it had a value similar to the above-mentioned stopping accuracy. Due to the error in the stopping accuracy, there is a discrepancy between the relative stopping position of the transfer device and the loading platform and the normal relative stopping position. When loading the automatic guided vehicle, it is necessary to provide the transfer device or the transport vehicle with a structure that eliminates the deviation, or to improve the stopping accuracy of the automatic guided vehicle.

As a known means of improving stopping accuracy, a plurality of hydraulic jacks are installed on an unmanned guided vehicle, a conical buried fire is formed in the rond part of the hydraulic jack, and a cone-shaped buried fire is formed at the regular stopping position on the floor of each station. A plurality of positioning protrusions having conical male portions having matching shapes are provided corresponding to the mounting positions of the hydraulic jacks, and when the automatic guided vehicle stops at a station, the hydraulic jacks are advanced and the positioning protrusions are attached to the respective positioning protrusions. There is a means for external fitting and positioning. As a result, the automatic guided vehicle is lifted from the floor and positioned at its normal stopping position.

[Problem to be solved by the invention]

However, in the above means, the positioning protrusion becomes an obstacle to traveling, and a large number of additional equipment such as a hydraulic power source is required, which increases the price and complicates the structure. Furthermore, since the above-mentioned means performs positioning by engaging the embedded flame and the male part, the positioning accuracy deteriorates due to the abrasion of the buried flame and the male part, and dust is generated due to abrasion powder. It could not be used in environments where positioning accuracy and cleanliness were specified.

Further, since a transfer device is provided for each station, if the transfer device is provided with a structure to eliminate the above-mentioned deviation, a large number of such structures will be required, leading to an increase in the price of the entire system.

Furthermore, if the conveyance vehicle is provided with a structure to eliminate the above-mentioned deviation, it is conceivable to use pole screws for positioning in the traveling direction and the direction crossing it, and to rotate and position using a gear mechanism in the vertical rotation direction. , pole screws and gear mechanisms require a lot of installation space, have a large number of parts, and are heavy.Also, ball screws and gear mechanisms have backlash, so if high precision is required, the accuracy of the parts used must be improved. However, there was a problem in that the cost was high.Furthermore, when a ball screw and gear mechanism were used, dust was generated due to abrasion powder, and it was necessary to take measures to prevent dust over a wide range.

The present invention has been made in view of the above circumstances, and uses an eccentric cam with a preload applied to the outer periphery to position the carrier vehicle loading platform in three directions: two directions in the horizontal plane and a rotational direction around a vertical axis. The object of the present invention is to provide a loading platform that is small and lightweight, and that can cleanly position the stop position with high precision and at low cost using low-precision parts.

[Means to solve the problem]

The loading platform according to the present invention is equipped on an automatically traveling transport vehicle, and includes a rotating stage that is rotatable in a rotational direction around a vertical axis of the transport vehicle, and a first moving stage that is movable separately in two directions in a horizontal plane. A loading platform having a platform and a second moving platform, the driving section being provided on each of the transport vehicle, the rotating platform, and the first moving platform, and including a plurality of eccentric cams and a driving device for rotating the eccentric cams. , provided on each of the rotating table, the first moving table, and the second moving table, and applying a preload to the outer periphery of the eccentric cam of each drive unit,
a driven part having a cam groove that rolls the eccentric cam, and the rotary table, the first moving table, and the second moving table provided with the driven part are moved through the conveyance vehicle by the rotational movement of the driving part. It is characterized in that it is designed to be positioned in different directions.

[Effect]

In the present invention, positioning of the stop position of the loading platform of the transport vehicle in two directions within the horizontal plane and in three directions around the vertical axis is performed.
This is done using an eccentric cam with a preload applied to the outer periphery, enabling compact, lightweight, and highly accurate positioning.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing examples thereof.

FIG. 1 is a left side view of a conveyance vehicle equipped with a loading platform according to the present invention, and the direction of travel of the conveyance vehicle is the direction indicated by the white arrow.

In the figure, 1 is supported by a pair of left and right drive wheels 2 (the right drive wheel is not shown) and four auxiliary wheels 3, 3 (the right auxiliary wheel is not shown) provided on the front, rear, left and right sides of the conveyance vehicle. It is the aircraft. The drive wheels 2 are attached to the center of the fuselage 1 at appropriate distances from each other on the left and right sides, and each drive motor (not shown) is coaxially and directly connected to each drive motor. to move aircraft 1 forward and backward. Further, the auxiliary wheels 3, 3 are rotatably attached to the front, rear, left and right sides of the body 1 at appropriate distances from each other so as to be rotatable about the vertical axis of the body 1.

A loading platform 4 for placing articles to be transported is provided on the upper part of the aircraft body 1, with its center being the same as that of the aircraft body 1, and the loading platform 4 is provided at the center of the aircraft body 1 in the traveling direction of the aircraft body 1. , a positioning means 5 in each direction that performs positioning in three directions: a direction perpendicular to the traveling direction, and a rotational direction around the vertical axis of the aircraft body 1.
It is attached to the body 1 so as to be movable and rotatable in the three directions by x, 5y, and 5θ. Further, the positioning means 5x, 5y, 5θ in each direction is a three-direction drive unit 6x,
6y and 6θ, it is possible to drive each of the three directions separately.

- 711.1 m of optical sensors are installed at the front and rear of the center of Aircraft 1 using industrial TV cameras to detect the stopping position of Aircraft 1.
are mounted downward at a distance from the center of the fuselage 1, indicating the stopping position of each process. The stopping position of the aircraft 1 is detected by the optical sensors 7a, 7B capturing images of the two circular positioning marks 8, 8. The imaged positioning mark 8
, 8 is provided inside the fuselage 1. A positioning control device 9 is provided inside the fuselage 1.

FIG. 2 is a partially cutaway side view showing each positioning means equipped with a driving section of the loading platform, which is the essential part of the present invention. A rectangular flat plate is fixed to the center of an inverted vertical member, and its base 57 is fastened to and mounted on two plaques 2°12 with its longitudinal direction perpendicular to the direction of movement of the fuselage 1. ing.

The base 57 has a square flat plate shape with sides slightly shorter than the horizontal length of the loading platform, and has a cylindrical boss part above the center part, and a swing bearing 52θ is installed inside the boss part. stand 57
A drive motor 66θ, which is a turning stepping motor, is attached to the lower center of the rear part of the motor, with its output shaft facing upward. An eccentric shaft 62θ having a predetermined eccentricity with respect to the output shaft is connected to the tip of the drive motor 66θ via a flexible joint 61θ, and an eccentric cam is connected to the upper end of the eccentric shaft 62θ. Two ball bearings 63θ and 63θ are fitted onto the outside. Further, the base 57 has a lower mounting flange on the upper side of the rear center, and a cylindrical bearing box 64θ is mounted coaxially with the drive motor 66θ, and the eccentric shaft 62θ
are two ball bearings 6 fitted inside the upper end of the bearing box 64θ.
5θ and 65θ, and the eccentric shaft 62θ
Due to the amount of eccentricity, the rotating table 50θ, which will be described later
rotate around.

The boss portion of a rotating table 50θ is fitted into the inner ring of the swivel bearing 52θ, and the boss portion of a rotating table 50θ is formed into a flat plate of regular size and external shape and has a cylindrical boss portion facing downward in the center. The rotary bearing 52θ allows the body 1 to rotate freely around the vertical axis in a rotational direction (hereinafter referred to as the θ direction) about the rotary bearing 52θ. In addition, a cylindrical bearing box 64x having mounting flanges at the upper and lower ends is attached to the lower part of the center of the front part of the rotating table 50θ, and the lower mounting flange is attached to the front-rear direction (hereinafter referred to as the X direction). A drive motor 66 using a stepping motor for moving the
x is installed with its output shaft facing upward. An eccentric shaft 6 having a predetermined eccentricity with respect to the drive motor output shaft is connected to the tip of the drive motor 66x via a flexible joint 61x.
2x are connected to each other, and two ball bearings 63x, 63x, which are eccentric cams, are fitted onto the upper end of the eccentric shaft 62x. The eccentric shaft 62x is supported by two ball bearings 65x, 65x fitted in the upper part of the bearing box 64x, and the first moving table 50x, which will be described later, is moved by the eccentricity of the eccentric shaft 62x. Move in the X direction.

In addition, four moving guides 52x and 5.2x in the X direction, which are made of rails of linear guides and are appropriately spaced on the front, rear, right and left sides of the rotating table 50θ, have their longitudinal directions substantially aligned with the X direction of the aircraft body 1. Let it be installed.

FIG. 3 is an enlarged perspective view showing the mounting state of the eccentric cam which is the drive part of the loading platform, and the ball bearings 63θ, 6 which are the eccentric cams are shown in FIG.
3θ is a driven part that has a rectangular flat plate shape and has a square bar-shaped convex part at one end, and an oblong eccentric cam groove 59θ whose length in the longitudinal force direction is in the same direction as the convex part is formed in the center. Some lower cam receiver 5
4θ and an upper cam receiver 53θ that has an eccentric cam groove 58θ similar to that of the lower cam receiver 54θ placed above the lower cam receiver 54θ. The lower cam receiver 54θ is adjusted by adjusting screws 55θ and 55θ screwed together at appropriate intervals in the longitudinal direction of the convex portion.
On the other hand, the eccentric cam groove can be freely slidable in a direction orthogonal to the longitudinal direction of the groove. In addition, the lower cam receiver 54θ and the upper cam receiver 5
3θ refers to the two ball bearings 63θ, 6 which are eccentric cams.
The outer ring of the upper ball bearing 63θ of 3θ is pressed against the side surface of the eccentric cam groove 58θ of the upper cam bearing 53θ on the adjustment bolt 55θ side, and the outer ring of the lower ball bearing 63θ is pressed against the side surface of the eccentric cam groove 59θ of the lower cam bearing 54θ. It is adjusted by the adjustment bolt 55θ so that it is pressed against the side opposite to the adjustment port 55θ.
This gives preload to each outer ring.

After this adjustment is completed, the lock nut 56θ locks the adjustment port 55θ from rotating. The lower cam receiver 54θ and the upper cam receiver 53θ are attached to the rear center of the rotating table 5oθ.

On the other hand, a moving guide 52x is attached to the rotating table 50θ.

52x..., the moving guides 52x, 52x
Four upper guides 51x, 51x, etc., which are formed by using transfer parts of linear guides that roll against ..., are attached to the lower part of the first moving table 50x, and the first moving table 50x is connected to the rotating table. It is possible to move freely in the X direction with respect to 50θ.

The first movable table 50x is in the shape of a flat plate with the same size and external shape as the rotary table 50θ, and on the lower side of the center on the left side is a bearing box 64y that has a cylindrical shape and has mounting flanges at the upper and lower parts thereof.
is installed. In addition, the lower mounting flange is attached in a direction perpendicular to the traveling direction, that is, in the left and right direction of the aircraft 1 (hereinafter referred to as
A drive motor 66y using a stamping motor for movement in the direction (referred to as "direction") is mounted with its output shaft facing upward.

An eccentric shaft 62y having a predetermined eccentricity with respect to the output shaft of the drive motor 66y is connected to the tip of the drive motor 6h via a flexible bearing 61y.
Two ball bearings 63y, 63 which are eccentric cams are installed at the upper end of the
y is fitted on the outside. The eccentric shaft 62V is connected to the bearing box 6.
Two ball bearings 65y, 65y fitted inside the top of 4y
The second movable table 50y, which will be described later, moves in the y direction depending on the eccentricity of the eccentric shaft 62y. Also, above the center of the front part of the first moving table 50x, there is a rotating table 50θ.
Upper cam receiver 53θ and lower cam receiver 54θ installed on
The upper cam receiver 53x and the lower cam receiver 54x, which have a similar structure, form the eccentric cam groove 58x.

59x is attached with the longitudinal direction as the y direction.

Further, four y-direction moving guides 52y, 52y, . . . using the rail portions of linear guides are attached to the upper side of the first moving table 50x at appropriate distances from each other on the front, rear, left and right sides. Four upper guides 51y, 51y, . . . , which are formed by using transfer parts of linear guides, are attached to the lower part of the second moving table 50y, which has a rectangular flat plate shape.
・It is attached so as to engage with the second moving table 50y.
It can be freely rolled in any direction. Further, at the lower center of the left side of the second moving table 50y, there are an upper cam receiver 53y and a lower cam receiver 54y, which are engaged with the ball bearings 63y and 63y and have the same structure as the upper cam receiver 53θ and the lower cam receiver 54θ. The longitudinal direction of the eccentric cam grooves 58y and 59Y is the X direction, and the upper and lower cam receivers 53θ and 54θ are the upper and lower cam receivers.
It is installed upside down. And the second moving platform 50y
A loading section 4 on which articles constituting the loading platform 4 are loaded
1 is installed.

FIG. 4 is a block diagram showing the configuration of a positioning control device for a conveyance vehicle according to the present invention. li
8. The position detection unit 91 detects the position of 8, the center position PA of the field of view of the optical sensor, PI and the detected positioning target! 8. Calculate the deviation from the center of gravity position PA'+ p, / of 8. Based on the deviation, calculate the deviation in the X direction, y direction, and θ direction to position the loading platform 4 of the conveyance vehicle in a direction that eliminates the deviation amount. A positioning correction value calculation unit 92 that calculates each positioning correction value ΔX, Δy, and Δθ, and each calculated positioning correction value ΔX.

Δy, Δθ and each drive motor 66x, 66y, 66θ
A motor drive unit 93 is provided which stores a relationship between the number of pulses applied to the motor and applies a predetermined number of pulses Lx+L'+Lθ to each of the drive motors 66x, 66y, and 66θ based on the memory.

Next, a method of controlling a conveyance vehicle and calculating a positioning correction value at a stop position according to the present invention will be explained.

The positioning correction values ΔX, Δy, and Δθ determine the center position G of the loading platform 4 and its X direction, and the intermediate position G' of the positioning marks 8, 8.
and the drive unit 6 of the loading platform in order to match the installation direction.
x, 6y, and 6θ, thereby eliminating the above-mentioned deviation.

FIG. 5 is a flowchart showing the flow of control;
The figure is a diagram explaining the method of calculating the positioning correction value.
The conveyance vehicle is automatically driven by a predetermined guidance device toward a station provided in each process, and the positioning mark 8
．． Optical sensor 7A stops at a position where the black circle in the center of 8 can be captured by a 7m field of view. When the transport vehicle stops,
The positioning mark as, 8 is imaged by the optical sensors 7a, 'b, and based on the imaging result, the positioning mark as, 8 is imaged by the position detecting section 91. ! The center positions PA, PB of the field of view and the positioning mark pA1 in a coordinate system in which the intermediate position G' of i8, 8 is the origin, the installation direction is the X' axis, and the direction perpendicular thereto is the Y' axis. p Distance from B+ dXA+ dYA+
Find dXl+d'IN. The positioning correction value calculation unit 92 calculates each positioning correction value ΔX, Δy using the calculation method described later using each distance dXA+dXIl+dYA+dYl found by the position detection unit 91.
, calculate 80. Then, the motor drive unit 93 converts each positioning correction value ΔX, Δy, Δθ into required pulses Lχ, Ly, Lθ of each drive motor, and the required pulse number Lx
, Ly, and Lθ are each driven by a drive motor 66x.

Output to 66y and 66θ.

The loading platform 4 is thereby positioned.

On the other hand, each positioning correction value ΔX, Δy, Δθ is calculated by the sixth
When the optical sensor 7A shown by the two-dot chain line in the figure captures the center of gravity of the positioning marks 8, 8 within a field of view of 7 m, the distance dXA+ dYA+ dXll+ dXY
is required. Using the determined distances, positioning correction values ΔX, Δy, and Δθ are determined using the following equations.

dy - (Iva doll However, 2L: Installation distance of positioning mark 8.8 above (1)
- Each positioning correction value ΔX, Δy according to equation (3).

Δθ is determined, and the motor drive unit 93 outputs a predetermined number of pulses Lx+Lyiθ corresponding to each positioning correction value ΔX, Δy, Δθ, and drives each drive motor 66x, 66y, 66θ, so that the loading platform 4 can be adjusted to the normal position. Position to the stop position. The amount of movement and rotation in the three directions due to the amount of eccentricity is
Since the values are sufficiently large compared to the above-mentioned deviation amount (in this example, ±15 m in the X direction, ±20111 in the y direction, and ±2° in the θ direction), even if the stopping precision of the transport vehicle is not sufficient, it is possible to transfer the loading platform and Relative position accuracy with the mounting device is ±1 in the X and Y directions.
It became possible to suppress the fi and θ directions within the permissible values.

Furthermore, in this embodiment, an eccentric cam using a ball bearing is used, and a preload is applied to its outer ring, so the structure of the positioning means is simplified and play between the eccentric cam and the eccentric cam groove can be suppressed. This enabled smooth positioning.

In this embodiment, a stepping motor is used as the drive motor, but the present invention is not limited to this, and any motor capable of position control, such as a servo motor with an encoder, may be used.

〔effect〕

As detailed above, in the loading platform according to the present invention, positioning in two directions in the horizontal plane and in three directions in the rotational direction around the vertical axis is performed by a drive unit using an eccentric cam with a preload applied to the outer periphery. This provides an equivalent effect of providing a loading platform that is small, lightweight, and capable of accurately and cleanly positioning the stop position at low cost.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a left side view of a transport vehicle equipped with a loading platform according to the present invention, and FIG.
The figure is a partially cutaway side view showing the positioning means of the loading platform.
The figure is an enlarged perspective view showing the mounting state of the eccentric cam, Figure 4 is a block diagram showing the configuration of the positioning control device, Figure 5 is a flowchart showing the flow of control, and Figure 6 is a method for calculating positioning values. It is a diagram. 1... Airframe 5... X direction positioning means 5y.
...X-direction positioning means 5θ...θ-direction positioning means Patent Applicant: Tsubakimoto Chain Co., Ltd. Patent attorney: Tomio Kono Procedural amendment (spontaneous) March 8, 1988 Patent application No. 12842 of 1988 No. 2, Name of the invention Loading platform 3, Relationship with the case of the person making the amendment Patent applicant location: 4-17-88 Tsurumi, Tsurumi-ku, Osaka City Name:
(335) Tsubakimoto Chain Co., Ltd. Representative Tomo Urabe - 4, Agent Address ■543 1-14-22 Shitennoji, Tennoji-ku, Osaka City Nisshin Building No. 207 "Detailed Description of the Invention" column 6. In the 1st line of page 12 of the statement of contents of the amendment, change the phrase "End lock" to "
Lock when finished,” he corrected. that's all

Claims (1)

[Scope of Claims] 1. A rotary table provided in an automatically traveling conveyance vehicle and rotatable in the rotational direction around the vertical axis of the conveyance vehicle, 2 in a horizontal plane;
A loading platform having a first moving platform and a second moving platform that are movable separately in directions, the loading platform having a plurality of eccentric cams provided on each of the conveyance vehicle, the rotary platform, and the first moving platform, and the eccentric cams. a drive section including a drive device for rotating; and a drive section provided in each of the rotating table, the first moving table, and the second moving table, applying a preload to the outer periphery of the eccentric cam of each drive section separately, and rotating the eccentric cam. and a driven part having a cam groove that moves, and the rotational movement of the driving part moves the rotating table, the first moving table, and the second moving table provided with the driven part in different directions with respect to the conveyance vehicle. A loading platform characterized by being configured to position the loading platform.