JP2008296830A - Steering device for conveying vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable manual traveling even if a switching mechanism is broken while enhancing a steering property during manual traveling. <P>SOLUTION: A solenoid tooth clutch 24 for switching it to the transmission state capable of transmitting motive power of a steering motor 23 for steering a steering wheel relative to an axle shaft 21 of the steering wheel and to the non-transmission state not capable of transmitting it is independently arranged. Further, a tooth clutch gear 26 is provided on a tooth clutch shaft of the solenoid tooth clutch 24, an axle shaft gear 22 engaged with the tooth clutch gear 26 is provided on the axle shaft 21, and the axle shaft 21 and the solenoid tooth clutch 24 are connected in the state that the motive power can be transmitted by the axle shaft gear 22 and the tooth clutch gear 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering apparatus for a transport vehicle having an automatic travel mode in which a steered wheel is automatically steered and a manual travel mode in which a steered wheel is manually steered by a driver's steering operation.

  Conventionally, a transport vehicle for towing and transporting a cart loaded with a load is used in a factory premises. In this type of transport vehicle, an automatic travel mode in which a magnetic guide tape affixed to the guideway is detected by a guide sensor and the steering wheel is automatically driven based on the detection result, and an operator There is a vehicle having a manual travel mode (manned travel mode) in which a steered wheel is steered by operating a steering handle to manually travel. In the following description, the “transport vehicle” refers to a vehicle having an automatic travel mode and a manual travel mode.

  When the transport vehicle is caused to travel in the manual travel mode, an operator who rides operates the steering handle and operates the axle shaft by operating the steering handle to steer the steered wheel and drive it. On the other hand, when the transport vehicle travels in the automatic travel mode, the travel is controlled wirelessly by a remote controller or the like, and the steered wheels are steered by operating the axle shaft by a steering motor mounted on the vehicle.

  By the way, when the steering motor is directly connected to the axle shaft through a power transmission member such as a chain as the structure of the transport vehicle, the steering wheel is operated in the manual travel mode, the steering is started, At the end, a force for rotating the rotor of the steering motor and a force for stopping the rotation are required. Therefore, when such a structure is adopted, the steering wheel operation in the manual travel mode becomes very heavy.

Therefore, conventionally, in order to solve such a problem, a steering device for a work vehicle described in Patent Document 1 has been devised. In the steering device of Patent Document 1, in a work vehicle capable of both unmanned traveling and manned traveling, during manned traveling, the switching device is switched to a manned position to transmit power from a DC motor used for steering during unmanned traveling. Switching to the off position, the operator's operation and DC motor connection are cut off to lighten the steering operation. And in the steering apparatus of patent document 1, the switching apparatus (claw clutch etc.) is directly arrange | positioned in the intermediate part of the steering shaft built in the steering column.
Japanese Utility Model Publication No. 6-37905

  Incidentally, the transport mode of the transport vehicle is switched between the manual travel mode and the automatic travel mode according to the use environment. For this reason, in the transport vehicle, the durability of the switching device that switches whether or not to transmit the power of the steering motor to the steering shaft (axle shaft) with the switching of the traveling mode is required. However, even if the switching device increases durability, there is no guarantee that it will not break depending on the usage environment. For this reason, if the switching device is disposed in the middle portion of the steering shaft as in Patent Document 1, if the switching device malfunctions and does not operate, not only the automatic travel mode but also the manual travel mode It will not be possible to run by.

  The present invention has been made paying attention to such problems existing in the prior art, and its purpose is to improve the steering performance during manual travel and to cause a malfunction of the switching mechanism. An object of the present invention is to provide a steering device for a transport vehicle that can be manually driven.

  In order to solve the above problems, the invention according to claim 1 is directed to an automatic travel mode in which a steered wheel is automatically steered and a steering wheel is manually steered by a steering wheel operation by a driver. In a steering apparatus for a transport vehicle that can be switched to a manual travel mode for traveling, the power of a steering motor that steers the steering wheel is transmitted to a connecting shaft that connects the steering wheel and the steering handle in the automatic traveling mode. A switching mechanism that can be switched to a possible transmission state and can be switched to a non-transmission state in which the power cannot be transmitted to the connection shaft in the manual travel mode is provided independently of the connection shaft and provided on the connection shaft The gist is that it is connected to the connecting shaft via a power transmission member.

  According to this, by providing the switching mechanism that transmits the power of the steering motor to the connecting shaft, it is possible to cut off the connection state between the steering motor and the connecting shaft during manual travel. Thereby, the steerability of the steered wheels during manual travel can be improved. Further, since the switching mechanism is provided independently without being provided directly to the connecting shaft, it is possible to perform manual travel even when a malfunction of the switching mechanism occurs.

  According to a second aspect of the present invention, in the steering apparatus for a transport vehicle according to the first aspect, the switching mechanism includes an electromagnetic clutch, and is switched from a non-transmission state to a transmission state by energization. It becomes the summary.

  According to this, when the operation of the transport vehicle is stopped (when the driving power is cut off), the state of the switching mechanism is set to the non-transmission state, and a driver's switching operation is required to switch to the transmission state. For this reason, when the operation of the transport vehicle is resumed, the steering wheel is not steered in the automatic travel mode against the intention of the driver.

  According to the present invention, it is possible to perform manual travel even when the switching mechanism is broken while improving the steering performance during manual travel.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which the present invention is embodied in a tow vehicle as a transport vehicle for towing a load loaded on a carriage will be described with reference to FIGS.
As shown in FIG. 1, the vehicle body 11 of the towing vehicle 10 includes a front frame 12 provided in front of the vehicle body 11 and a rear frame 13 provided in the rear of the vehicle body 11. The rear frame 13 is provided with a traction mechanism (not shown). A standing-type driver's seat 14 is provided at substantially the center in the front-rear direction of the vehicle body 11. Steering wheels 16 (shown in FIG. 3) are provided below the front portion of the vehicle body 11, and drive wheels 17 are provided below the rear portion of the vehicle body 11. A battery hood 15 that covers the upper part of a storage chamber (not shown) is provided on the rear frame 13 disposed behind the driver's seat 14 so as to be openable and closable. The vehicle body 11 is equipped with a traveling motor MT (shown in FIG. 3) using a battery as a driving source, and the driving wheels 17 are given driving force from the traveling motor MT. That is, the tow vehicle 10 of the present embodiment is a battery type (electric type) vehicle.

  The driver's seat 14 is provided with a bar handle 18 as a steering handle for an operator (driver) who gets on the vehicle to operate the handle. The bar handle 18 is connected to a steering shaft (shown in FIG. 3) 20 built in the steering column 19, and the steering shaft 20 is connected to an axle shaft 21 to which the steering wheel 16 is mounted. Accordingly, the tow vehicle 10 can be manually driven in the manual travel mode by steering the steering wheel 16 by the driver operating the bar handle 18 (rotating operation in the left-right direction). . In the present embodiment, the steering shaft 20 and the axle shaft 21 constitute a connecting shaft that connects the steering wheel 16 and the bar handle 18.

  As shown in FIG. 2, an axle shaft gear 22 as a power transmission member is mounted on the axle shaft 21 so as to be integrally rotatable. Then, on the rear side (driver's seat 14 side) of the front frame 12, when the towing vehicle 10 is automatically driven in the automatic travel mode along the guide path made of a magnetic guide tape GT (shown in FIG. 3), A steering motor 23 for steering the steered wheels 16 and an electromagnetic tooth clutch 24 as an electromagnetic clutch are provided. The electromagnetic tooth clutch 24 is a magnetically actuated clutch that has a pair of tooth rings 24a and 24b shown in FIG. 3 and transmits torque when the teeth (teeth) of these tooth rings 24a and 24b mesh with each other. When the electromagnetic tooth clutch 24 is energized and energized by a coil (not shown), the tooth rings 24a and 24b are engaged with each other and the clutch is connected to transmit torque. On the other hand, when the coil is de-energized and de-energized, the electromagnetic tooth clutch 24 is disengaged from the tooth rings 24a and 24b, and the clutch is disengaged, thereby interrupting torque transmission.

  A rotor (not shown) of the electromagnetic tooth clutch 24 is attached to a tooth clutch shaft 25 (shown in FIG. 3) of the electromagnetic tooth clutch 24 so as to be integrally rotatable, and the tooth clutch shaft 25 serves as an input shaft of the clutch. One tooth ring (the tooth ring 24a in this embodiment) of the pair of tooth clutches is attached to the rotor so as to be integrally rotatable. A tooth clutch gear 26 that is always meshed with the axle shaft gear 22 of the axle shaft 21 is attached to one end (first end) of the tooth clutch shaft 25 so as to be integrally rotatable. Of the pair of tooth clutches, the other tooth ring (the tooth ring 24b in the present embodiment) of the pair of tooth clutches is attached to the tooth clutch gear 26 so as to be integrally rotatable. The other end (second end) of the tooth clutch shaft 25 is connected to a motor rotating shaft 27 (shown in FIG. 3) of the steering motor 23 so that power can be transmitted, and the other end of the tooth clutch shaft 25 is steered. A chain 28 is stretched around the motor rotating shaft 27 of the motor 23.

  In the present embodiment, as shown in FIG. 2, the tooth clutch shaft 25 of the electromagnetic tooth clutch 24 and the motor rotation shaft 27 of the steering motor 23 are extended in the same direction as the extension direction of the axle shaft 21. The electromagnetic tooth clutch 24 and the steering motor 23 are juxtaposed in a vertically placed state. Thereby, the steering motor 23 and the electromagnetic tooth clutch 24 can be disposed in a space-saving manner on the rear surface side of the front frame 12, that is, on the driver's seat 14 side. The electromagnetic tooth clutch 24 is connected to the axle shaft 21 via a transmission mechanism including the axle shaft gear 22 and the tooth clutch gear 26 of the axle shaft 21 and is not provided directly to the axle shaft 21 but independently. It is arranged. That is, it is indirectly provided with respect to the axle shaft 21. Similarly, the steering motor 23 is connected via a transmission mechanism including a chain 28 that spans the axle shaft 21 and the motor rotation shaft 27, and the steering motor 23 and the electromagnetic tooth clutch 24 are provided independently.

  With such a configuration, the power generated by the rotation of the steering motor 23 causes the axle shaft gear 22 to be engaged with the tooth rings 24a and 24b when the electromagnetic tooth clutch 24 is excited (in the automatic travel mode). Is transmitted to the axle shaft 21 via. That is, the electromagnetic tooth clutch 24 has a tooth clutch shaft 25 on the side of the tooth clutch gear 26 that meshes with the tooth ring 24a on the rotor side, as the tooth clutch shaft 25, the rotor and the tooth ring 24a rotate together with the motor rotation shaft 27 when the steering motor 23 rotates. Power is transmitted to the tooth ring 24b to rotate the tooth clutch gear 26. Thus, in the automatic travel mode, the power of the steering motor 23 is transmitted to the axle shaft gear 22 of the axle shaft 21 via the electromagnetic tooth clutch 24 and the tooth clutch gear 26, and the axle shaft 21 receives the transmitted power. The steering wheel 16 is steered by the operation of.

  On the other hand, when the electromagnetic tooth clutch 24 is de-energized (in the manual travel mode), the power of the steering motor 23 is not transmitted to the axle shaft 21 by the meshing of the tooth rings 24a and 24b. That is, in the manual travel mode, the axle shaft 21 and the axle shaft gear 22 connected to the steering shaft 20 are rotated according to the handle operation amount by the handle operation of the bar handle 18, and mesh with the axle shaft gear 22 by the rotation. The tooth clutch gear 26 rotates. However, in a state where the meshing of the tooth rings 24a and 24b is released, only the tooth clutch gear 26 rotates in a free state, so that the rotation of the tooth clutch gear 26 is the tooth clutch. It is not transmitted to the shaft 25. As a result, in the manual travel mode, both the tooth clutch shaft 25 and the motor rotating shaft 27 connected to the tooth clutch shaft 25 do not rotate. In the manual travel mode, the tooth clutch shaft 25 and the motor rotating shaft 27 are released from the connected state to the tooth clutch gear 26, and the tooth clutch gear 26 is rotated in a free state by the handle operation. It becomes lighter.

  In the present embodiment, the electromagnetic tooth clutch 24, the tooth clutch shaft 25, and the tooth clutch gear 26 constitute a switching mechanism. By this switching mechanism, it is possible to switch between a transmission state where the power of the steering motor 23 can be transmitted to the axle shaft 21 and a non-transmission state where the power cannot be transmitted. In the electromagnetic tooth clutch 24, when the tow vehicle 10 is in a stopped state (a state in which the driving power is cut off by turning off the power supply), the energization of the coils is interrupted to release the engagement of the tooth rings 24a and 24b. In other words, in the present embodiment, the electromagnetic tooth clutch 24 is in a state in which the tooth rings 24a and 24b are engaged with each other only when the coil is energized in the automatic travel mode so that torque can be transmitted. On the other hand, in the present embodiment, the electromagnetic tooth clutch 24 is configured so that the coils of the tooth rings 24a and 24b are disengaged by switching off the coil when switching to the manual travel mode and when the operation of the towing vehicle 10 is stopped. Transmission becomes impossible.

  As shown in FIG. 3, the vehicle body 11 is equipped with a controller 30 that constitutes a control circuit of the tow vehicle 10 and mainly performs traveling control. The controller 30 is composed of a microcomputer. The controller 30 is connected to the steering motor 23 and the electromagnetic tooth clutch 24. The controller 30 controls the rotation of the steering motor 23 by transmitting an electric signal to the motor control circuit of the steering motor 23, and transmits an electric signal (excitation signal and non-excitation signal) to the coil of the electromagnetic tooth clutch 24. The energization and de-energization of the tooth clutch 24 is controlled.

  Further, as shown in FIG. 3, a receiver 32 that receives a signal from a transmitter (remote control device) 31 is mounted on the vehicle body 11, and the receiver 32 is connected to the controller 30. The transmitter 31 instructs switching to an automatic travel mode in which the tow vehicle 10 automatically travels. Further, as shown in FIG. 3, the vehicle body 11 is connected with a guide sensor GS that detects the guide tape GT, converts the amount of deviation between the guide tape GT and the towing vehicle 10 into an electrical signal, and transmits the electrical signal to the controller 30. Yes. The controller 30 receives an electrical signal from the guide sensor GS in the automatic travel mode, and controls the steering motor 23 to control the direction of the steered wheels 16. Further, an operation switch 33 for switching the traveling mode of the tow vehicle 10 is provided in the driver seat 14 of the vehicle body 11. The operation switch 33 is connected to the controller 30. The tow vehicle 10 is switched between the manual travel mode and the automatic travel mode by the operator switching the operation switch 33. The controller 30 receives the operation signal of the operation switch 33 and controls the traveling of the towing vehicle 10 according to the traveling mode instructed by the operation signal.

Hereinafter, the operation of the towing vehicle 10 of this embodiment will be described.
First, the case of the automatic travel mode will be described.
Switching to the automatic travel mode is performed by operating the transmitter 31. When the controller 30 is switched to the automatic travel mode, the coil of the electromagnetic tooth clutch 24 is energized and excited. In this state, the tooth rings 24a and 24b of the electromagnetic tooth clutch 24 are engaged with each other so that the clutch is engaged. The controller 30 receives an electrical signal from the guide sensor GS and controls the steering motor 23. Thus, the power of the steering motor 23 is transmitted to the axle shaft gear 22 meshing with the tooth clutch gear 26 via the tooth clutch shaft 25 and the tooth clutch gear 26 of the electromagnetic tooth clutch 24. Then, the axle shaft 21 is operated by the power of the steering motor 23 transmitted through the axle shaft gear 22, and the direction of the steering wheel 16 is controlled. Further, the controller 30 operates the traveling motor MT to automatically travel the tow vehicle 10 at a predetermined speed along the guide path. The predetermined speed in the automatic travel mode is an instruction from the transmitter 31 or a predetermined constant speed.

Next, the case of the manual travel mode will be described.
Switching to the manual travel mode is performed by operating the operation switch 33. When the controller 30 is switched to the manual travel mode, the coil of the electromagnetic tooth clutch 24 is de-energized and de-energized. In this state, the engagement of the tooth rings 24a and 24b of the electromagnetic tooth clutch 24 is released and the clutch is disengaged. The steering wheel 16 is controlled in its direction by operating the axle shaft 21 connected to the steering shaft 20 in accordance with the amount of the steering wheel operation when the driver operates the bar handle 18.

  In the manual travel mode, the meshing of the tooth rings 24a and 24b of the electromagnetic tooth clutch 24 is released. Therefore, even when the axle shaft gear 22 that rotates integrally with the axle shaft 21 is rotated by the operation of the bar handle 18 and the tooth clutch gear 26 that meshes with the axle shaft gear 22 is rotated, the two of the electromagnetic tooth clutch 24 is rotated. Torque is not transmitted to the motor rotation shaft 27 of the steering motor 23 via the scratch shaft 25. Therefore, the steering wheel 16 is improved in steering performance by the steering operation by adopting a mechanism that does not rotate the motor rotating shaft 27 of the steering motor 23 in conjunction with the steering operation of the bar handle 18. That is, the driver can steer the steered wheels 16 by lightly moving the bar handle 18 in the manual travel mode. Further, the controller 30 operates the traveling motor MT to manually travel the tow vehicle 10 at a predetermined speed along the guide path. The predetermined speed in the manual travel mode is a speed according to the amount of accelerator operation performed by the driver.

Therefore, according to the present embodiment, the following effects can be obtained.
(1) The electromagnetic tooth clutch 24 is provided independently of the axle shaft 21 via the axle shaft gear 22 and the tooth clutch gear 26. That is, the switching mechanism for switching between the state in which the power of the steering motor 23 is transmitted to the axle shaft 21 and the state in which the power is not transmitted to the axle shaft 21 is not provided directly on the axle shaft 21. Accordingly, the electromagnetic tooth clutch 24 is provided to improve the steering performance during manual driving, and the electromagnetic tooth clutch 24 is provided independently of the axle shaft 21 so that the vehicle can be manually driven even if malfunction occurs. Can do.

  (2) The electromagnetic tooth clutch 24 is in a state where the tooth rings 24a and 24b are engaged with each other when the coil is energized and can transmit power. It becomes a state. For this reason, in order to switch to the transmission state in which the power of the steering motor 23 is transmitted, a driver's switching operation is required. Therefore, when the driving of the towing vehicle 10 is resumed, the steering wheel 16 is not steered in the automatic travel mode against the intention of the driver.

(3) Moreover, since the structure which switches the motive power transmission state of the steering motor 23 with the electromagnetic tooth clutch 24 is employ | adopted, space reduction of a switching mechanism is realizable.
In addition, you may change the said embodiment as follows.

In the embodiment, the steering handle may be a steering handle instead of the bar handle 18.
The embodiment may be embodied in a seat-type tow vehicle in which a seat is provided in the driver's seat 14.

  In the embodiment, the electromagnetic tooth clutch that connects the axle shaft 21 and the steering motor 23 may be changed to another clutch. For example, it may be changed to a friction clutch (wet clutch and dry clutch).

The embodiment may be embodied in other transport vehicles (for example, golf carts) that transport loads.
In the embodiment, instead of the chain 28, the tooth clutch shaft 25 of the electromagnetic tooth clutch 24 and the motor rotating shaft 27 may be connected by a gear mechanism.

  In the embodiment, instead of the axle shaft gear 22 and the tooth clutch gear 26, the axle shaft 21 and the tooth clutch shaft 25 of the electromagnetic tooth clutch 24 may be connected by a belt or a chain.

Next, a technical idea that can be grasped from the above embodiment and another example will be added below.
(A) The steering device for a transport vehicle according to claim 2, wherein the electromagnetic clutch is an excitation-actuated type tooth clutch.

  (B) The technical point in which the input shaft of the electromagnetic clutch and the rotating shaft of the steering motor are extended in the same direction as the connecting shaft for steering, and the electromagnetic clutch and the steering motor are juxtaposed in a vertically placed state. The transport vehicle steering apparatus according to the concept (a).

  (C) A transport vehicle equipped with the steering device according to claims 1 and 2 and technical ideas (a) and (b).

The perspective view which shows the outline of the towing vehicle of this embodiment. The perspective view which shows the connection structure of an axle shaft and a steering motor. The block diagram which shows the electric structure of a tow vehicle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Traction wheel, 16 ... Steering wheel, 18 ... Bar handle, 21 ... Axle shaft, 22 ... Axle shaft gear, 23 ... Steering motor, 24 ... Two clutch, 24a, 24b ... Two ring, 25 ... Two clutch shaft, 26 ... tooth clutch gear, 27 ... motor rotating shaft, 28 ... chain.

Claims (2)

In a steering apparatus for a transport vehicle capable of switching between an automatic travel mode in which a steered wheel is automatically steered and a manual travel mode in which a steered wheel is manually steered by a steering wheel operation by a driver. ,
The power of a steering motor that steers the steered wheels in the automatic travel mode can be switched to a transmission state that can be transmitted to a connection shaft that connects the steering wheels and the steering handle, and the power is transmitted to the connection shaft in the manual travel mode. And a switching mechanism that can be switched to a non-transmission state incapable of being transmitted independently of the connection shaft and connected to the connection shaft via a power transmission member provided on the connection shaft. Steering device.   2. The transport vehicle steering apparatus according to claim 1, wherein the switching mechanism includes an electromagnetic clutch, and is switched from a non-transmission state to a transmission state by energization, and enters a non-transmission state when de-energized.

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