JP4017471B2 - forklift - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a forklift in which drive wheels are provided so as to be steerable by 360 °.
[0002]
[Prior art]
Conventionally, a seated reach forklift (hereinafter simply referred to as a forklift) 21 as shown in FIG. 6 has been used. The driver sits on the seat 22 of the forklift 21, operates the handle 25 with the left hand, operates the directional switch 23 shown in FIG. 7 provided on the driving operation table 29 with the right hand, and changes the traveling direction of the forklift 21. Control. Further, the driver controls the rotational speed of the traveling motor, that is, the traveling speed of the forklift 21 by adjusting the amount of depression of an accelerator pedal provided on the floor 26 of the forklift 21.
[0003]
In such a forklift 21, the stopper is such that the steering angle of the drive wheel 24 is limited to be within a range of ± 90 ° with respect to the front direction of the forklift 21, or the stopper is not provided and is driven. Some wheels 24 are provided so that they can be steered 360 °. In the former, the tilting direction of the directional switch 23 and the rotation direction of the traveling motor that drives the drive wheels 24 are uniquely set. For example, the directional switch 23 is viewed in the forward direction of the forklift 21, that is, viewed from the driver. When tilted to the front side, the forklift 21 is moved forward by the forward running motor. In the latter case, the former configuration may be applied as it is, and the tilt direction of the directional switch 23 and the rotation direction of the traveling motor may be uniquely set.
[0004]
8 to 12 show the state of the forklift 21 when the driver gradually rotates the handle 25. However, for convenience of explanation, the forklift 21 in FIGS. 8 to 12 is expressed in a simplified manner. FIGS. 8 to 12 show that the directional switch 23 is tilted toward the black triangle of the two triangles representing the directional switch 23. When the directional switch 23 is tilted in the forward direction of the forklift 21, that is, toward the front as viewed from the driver, the traveling motor rotates in the forward direction and the drive wheel 24 rotates in the forward direction. Is tilted in the backward direction of the forklift 21, that is, on the heel side as viewed from the driver, the traveling motor is reversed and the drive wheel 24 is reversed.
[0005]
FIG. 8 shows a case where the driving wheel 24 is rotating forward and the steering angle of the forklift 21 with respect to the forward direction is 0 °. As indicated by the arrows, the forklift 21 goes straight forward. FIG. 9 shows a case where the drive wheel 24 is rotating forward and the steering angle is −45 °. As indicated by the arrow, the forklift 21 advances in the direction of 45 ° diagonally forward to the right. FIG. 10 shows a case where the drive wheel 24 is rotating forward and the steering angle is −90 °. As indicated by the arrow, the forklift 21 is located at the midpoint between the two following driven wheels 27a and 27b. Turn around the right side of the vehicle. FIG. 11 shows a case where the driving wheel 24 is rotating forward and the steering angle is −135 °, and as indicated by the arrow, the forklift 21 advances in the direction of 45 ° diagonally rightward. FIG. 12 shows a case where the driving wheel 24 is rotating forward and the steering angle is −180 ° (or 180 °). As indicated by the arrow, the forklift 21 moves straight forward.
[0006]
As described above, in the forklift 21 in which the drive wheels 24 can be steered by 360 °, the driver can freely change the traveling direction of the forklift 21 only by operating the handle 25, so that the steering angle of the drive wheels 24 is limited by the stopper. There is an advantage that the operability is high compared to what has been done.
[0007]
[Problems to be solved by the invention]
By the way, as shown in FIGS. 8 to 12, when the steering angle of the drive wheel 24 is within −90 °, the tilting direction of the directional switch 23 and the traveling direction of the forklift 21 are the same, but the steering angle is −180. When the angle is from -90 °, the direction in which the directional switch 23 tilts and the direction in which the forklift 21 travels are opposite.
[0008]
When the forklift 21 is temporarily stopped to perform a cargo handling operation, and when the driver tries to move again or when the driver changes, the driver assumes that the driver has operated as it is and the direction of the directional switch 23 and the travel of the forklift 21. It may not be possible to determine whether the directions match, and in such a case, the direction switch 23 is tilted in the direction in which the forklift 21 is intended to travel intuitively without considering the steering angle of the drive wheels 24. Sometimes. For example, in the forklift 21 described above, it is conceivable to tilt the direction switch 23 toward the front side in order to move the forklift 21 forward. At that time, if the steering angle of the drive wheels 24 is −180 °, the forklift 21 Will go backwards. If the forklift travels in the direction opposite to the driver's intention as described above, not only will the surroundings be dangerous, but the driver may be confused and cause further driving errors.
[0009]
Therefore, an object of the present invention is to provide a forklift in which driving wheels can be always steered in a direction intended by a driver and provided with driving wheels capable of being steered 360 °.
[0010]
[Means to solve the problem]
In order to achieve the above object, a forklift provided with the driving wheels of the present invention so as to be steerable by 360 ° includes a traveling direction selection means operated by a driver to select a traveling direction of the forklift, and the driving wheels. When the traveling direction is selected by the steering angle detecting means for detecting the steering angle and the traveling direction selecting means, the rotational direction of the driving wheel is determined based on the traveling direction and the steering angle, and the selection is performed. Traveling control means for controlling the forklift to travel in the traveling direction.
[0011]
When the driver operates the travel direction selection means to select the travel direction of the forklift, the selected travel direction is input to the travel control means. Further, the steering angle of the drive wheel detected by the steering angle detection means is also input to the travel control means. The travel control means determines the rotation direction of the drive wheels so that the forklift travels in the input travel direction. For example, when traveling is instructed by the accelerator pedal being depressed by the driver, the driving wheel is driven in the rotational direction of the driving wheel determined by the traveling control means, and the forklift is selected by the driver. Travel in the direction of travel. That is, the traveling direction selected by the driver using the traveling direction selection means and the actual traveling direction of the forklift always coincide with each other.
[0012]
The travel direction selection means can select either forward or reverse as the travel direction of the forklift, and the steering angle detection means can detect the steering angle of the drive wheel in a range of −180 ° to 180 ° with respect to the forward direction of the forklift. In the above configuration, the traveling control means, when the steering angle detecting means detects a steering angle within ± 90 ° with respect to the forward direction of the forklift, and when the forward direction is selected by the traveling direction selecting means, When the rotation direction of the drive wheel is the forward rotation direction and the steering angle detection means detects a steering angle within ± 90 ° with respect to the forward direction of the forklift, reverse travel is selected by the travel direction selection means. The rotation direction of the drive wheel is set to the reverse direction, and the steering angle detection means makes 90 ° to 180 ° or −180 ° to the front direction of the forklift When the forward direction is selected by the traveling direction selection means while a steering angle of −90 ° is detected, the rotation direction of the drive wheel is set to the reverse direction, and the steering angle detection means sets the forward direction of the forklift. On the other hand, when the reverse direction is selected by the traveling direction selection means in a state where the steering angle of 90 ° to 180 ° or −180 ° to −90 ° is detected, the rotation direction of the drive wheel is set to the normal rotation direction. You just have to do it.
[0013]
In this way, even if the driver does not operate while considering the steering angle of the drive wheel, the driver can select the forward by the traveling direction selection means to advance the forklift, and can select the reverse to reverse the forklift. . Further, when forward or reverse is selected by the travel direction selection means, the travel control means determines the rotation direction of the drive wheel as the forward rotation direction or the reverse rotation direction. The drive wheel is driven in the determined rotational direction unless the forward or reverse is selected again, so that the drive wheel that can change the traveling direction of the forklift only by operating the steering wheel is provided so that it can be steered 360 °. The inherent characteristics of the forklifts that are produced will not be impaired.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a seated reach type forklift will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a functional block diagram of a travel drive system provided in a forklift according to the present embodiment, FIG. 2 is a partial cross-sectional view showing a main part of the forklift according to the present embodiment, and FIG. 3 shows a steering angle of the forklift according to the present embodiment. FIG. 4 is an explanatory view showing the steering angle detecting means according to the present embodiment, and FIG. 5 is a flowchart for determining the control mode of the traveling motor according to the present embodiment. In addition, since the whole structure of the forklift 21 in this Embodiment is the same as that of the prior art shown in FIG. 6, FIG. 7, the same code | symbol shall be attached | subjected and detailed description is abbreviate | omitted.
[0016]
The drive wheels 24 provided in the forklift 21 of the present embodiment are driven by the travel motor 3 shown in FIG. 1, and the travel motor 3 is controlled by the travel control means 2. The traveling control means 2 includes a signal indicating the tilting direction of the directional switch 23 output from the directional switch 23 serving as the traveling direction selecting means, and the driving wheel 24 output from the limit switch 6 constituting the steering angle detecting means. A signal corresponding to the steering angle is input. Then, the traveling control means 2 rotates the traveling motor 3 as described in detail below based on the input signal indicating the tilt direction of the directional switch 23 and the signal corresponding to the steering angle of the drive wheel 24. By controlling the direction, the rotation direction of the drive wheel 24 is controlled. Further, a signal indicating the depression amount of the accelerator pedal 7 is also input to the traveling control means 2, and the traveling control means 2 is based on the signal indicating the depression amount of the accelerator pedal 7. The rotation speed is controlled. The directional switch 23 is provided so as to be tiltable in the front-rear direction of the forklift 21. When the directional switch 23 is tilted in the front direction, a signal indicating that the directional switch 23 is tilted forward is provided. When the forklift 21 is tilted rearward, a signal indicating that the tilting direction of the directional switch 23 is rearward is output. The directional switch 23 has a built-in spring for returning to the neutral state where the directional switch 23 is not tilted. When the driver releases the hand from the directional switch 23, the directional switch 23 is actuated by the action of the spring. It returns to the neutral state.
[0017]
FIG. 2 shows a drive mechanism and a steering mechanism of the drive wheel 24. The rotation of the traveling motor 3 is transmitted to the gear box 37 via the drive shaft A, and then transmitted to the drive wheels 24 supported by the gear box 37. With such a drive mechanism, when the traveling motor 3 rotates in the forward direction, the driving wheel 24 rotates in the forward direction, and when the traveling motor 3 rotates in the reverse direction, the driving wheel 24 rotates in the reverse direction. On the other hand, the rotation of the steering motor 34 is transmitted to the steering gear 35 fixed to the gear box 37 via the reduction gear 36. As the steering gear 35 rotates, the drive wheels 24 are steered together with the gear box 37. The steering gear 35 and the drive shaft A are disposed coaxially. Further, a protrusion 38 is formed on the upper surface of the steering gear 35, and the lever of the limit switch 6 comes into contact with the protrusion 38.
[0018]
Here, as shown in FIG. 3, the inner angle formed by the forward direction of the forklift 21 and the direction B in which the forklift 21 travels by the driving wheel 24 when the driving wheel 24 is driven in the forward rotation direction by the traveling motor 3. θ is the steering angle of the drive wheel 24. Then, a state where the front direction of the forklift 21 and the direction B coincide with each other is defined as a steering angle θ = 0 °, and the steering on the side where the driving wheels 24 are steered counterclockwise in plan view from the steering angle θ = 0 °. The angle θ is represented by a positive value, and the steering angle θ on the side steered clockwise is represented by a negative value. Since the steering mechanism included in the forklift 21 according to the present embodiment is not provided with a stopper or the like that restricts the steering angle θ of the drive wheel 24, the drive wheel 24 can be steered 360 °. A possible value of the steering angle θ of the drive wheel 24 is in a range of −180 ° <θ ≦ 180 ° (the steering angle θ = −180 ° and the steering angle θ = 180 ° are in the same state, and therefore steering is performed here). Angle expressed as θ = 180 °).
[0019]
The protrusion 38 formed on the upper surface of the steering gear 35 has a semi-cylindrical shape as shown in FIGS. 4A and 4B, and the steering angle θ of the drive wheel 24 is −180 ° <θ <−90. When the angle is in the range of ° or 90 ° <θ ≦ 180 °, the lever of the limit switch 6 comes into contact with the protrusion 38 and is turned on, and the steering angle θ of the drive wheel 24 is −90 ° ≦ θ ≦ 90. When it is in the range of °, the limit switch 6 is turned off. The limit switch 6 and the projection 38 constitute the steering angle detection unit 5, and an ON signal from the limit switch 6 is input to the travel control unit 2.
[0020]
In the above configuration, when the driver steers the handle 25, the steering motor 34 rotates the reduction gear 36 according to the operating angle of the handle 25, whereby the steering gear 35 that is linked to the reduction gear 36 rotates. As described above, when the steering gear 35 rotates in accordance with the steering operation and the steering angle θ of the driving wheel 24 falls within the range of −180 ° <θ <−90 ° or 90 ° <θ ≦ 180 °, the protrusion 38 is moved to the limit switch. By pushing up the lever 6, the limit switch 6 is turned on. When the ON signal of the limit switch 6 is input to the traveling control unit 2, the traveling control unit 2 sets the steering angle θ of the drive wheels 24 to −180 ° <θ <−90 ° or 90 ° <θ ≦ 180 °. Determined to be in range. Conversely, if the limit switch 6 is in an off state and no on signal is input, the traveling control means 2 determines that the steering angle θ of the drive wheels 24 is in the range of −90 ° ≦ θ ≦ 90 °.
[0021]
Hereinafter, the control procedure according to the present embodiment will be described with reference to FIG.
First, the traveling control means 2 determines the state of the limit switch 6 (S1). When it is determined that the limit switch 6 is in the OFF state, the traveling control unit 2 determines whether or not the signal indicating the traveling direction input from the directional switch 23 to the traveling control unit 2 is the forward direction ( S2).
[0022]
If it is determined in step S2 that the vehicle is in the forward direction, the traveling control unit 2 sets the control mode of the traveling motor 3 to the normal rotation mode, and controls the traveling motor 3 in the normal rotation mode (S3). If it is determined in step S2 that the vehicle is not in the forward direction, it is then determined whether the signal indicating the traveling direction input from the directional switch 23 to the traveling control means 2 is in the backward direction (S4).
[0023]
If it is determined in step S4 that the vehicle is in the backward direction, the traveling control means 2 sets the control mode of the traveling motor 3 to the reverse rotation mode, and controls the traveling motor 3 in the reverse rotation mode (S5). If it is determined in step S4 that it is not the backward direction, the direction of tilting of the directional switch 23 is neither forward nor backward, that is, the directional switch 23 is in a neutral state where it is not tilted. The means 2 does not set the control mode again, and as a result, the current control mode is maintained.
[0024]
On the other hand, if it is determined in step S1 that the limit switch 6 is in the ON state, it is then determined whether or not the signal indicating the traveling direction input from the directional switch 23 to the traveling control means 2 is the forward direction (S6). ).
[0025]
If it is determined in step S6 that the vehicle is in the forward direction, the traveling control means 2 sets the control mode of the traveling motor 3 to the reverse rotation mode, and controls the traveling motor 3 in the reverse rotation mode (S5). If it is determined in step S6 that the vehicle is not in the forward direction, it is then determined whether the signal indicating the traveling direction input from the directional switch 23 to the traveling control means 2 is in the backward direction (S7).
[0026]
If it is determined in step S7 that the vehicle is in the backward direction, the traveling control unit 2 sets the control mode of the traveling motor 3 to the normal rotation mode, and controls the traveling motor 3 in the normal rotation mode (S3). If it is determined in step S7 that it is not backward, the direction of tilting of the directional switch 23 is neither forward nor backward, that is, the directional switch 23 is in a neutral state where it is not tilted. The means 2 does not set the control mode again, and as a result, the current control mode is maintained.
[0027]
The change from the normal rotation mode to the reverse rotation mode, or the change from the reverse rotation mode to the normal rotation mode is performed by switching the polarity of the traveling motor 3.
[0028]
By the way, when the accelerator pedal 7 is depressed, the traveling control means 2 applies a voltage corresponding to the amount of depression to the traveling motor 3. For example, the accelerator pedal 7 is depressed in the forward rotation mode. Then, the traveling control means 2 rotates the traveling motor 3 in the normal direction, and reverses the traveling motor 3 when the accelerator pedal 7 is depressed in the reverse rotation mode.
[0029]
When the driver tilts the directional switch 23 forward and depresses the accelerator pedal 7 when the steering angle θ of the drive wheel 24 is in a range of −90 ° ≦ θ ≦ 90 ° (the limit switch 6 is in an off state) The traveling control means 2 controls the traveling motor 3 in the normal rotation mode, and the forklift 21 moves forward. Further, when the steering angle θ of the drive wheel 24 is in the range of −180 ° <θ <−90 ° or 90 ° <θ ≦ 180 ° (the limit switch 6 is in the on state), the directional switch 23 is tilted forward. When the accelerator pedal 7 is depressed, the traveling control means 2 controls the traveling motor 3 in the reverse rotation mode, and the forklift 21 moves forward.
[0030]
On the other hand, when the steering angle θ of the drive wheel 24 is in a range of −90 ° ≦ θ ≦ 90 ° (the limit switch 6 is in an off state), the driver tilts the directional switch 23 backward and depresses the accelerator pedal 7. Then, the traveling control means 2 controls the traveling motor 3 in the reverse rotation mode, and the forklift 21 moves backward. Further, when the steering angle θ of the drive wheel 24 is in a range of −180 ° <θ <−90 ° or 90 ° <θ ≦ 180 ° (the limit switch 6 is in an on state), the directional switch 23 is tilted backward. When the accelerator pedal 7 is depressed, the traveling control means 2 controls the traveling motor 3 in the normal rotation mode, and the forklift 21 moves backward.
[0031]
As described above, according to the present embodiment, the forklift 21 always travels in the direction in which the directional switch 23 is tilted, and the forklift is in the direction opposite to the driver's intention as seen in the conventional forklift. No longer running. Therefore, the driver can safely perform the work by running the forklift as intended. Further, when the directional switch 23 is tilted, the traveling control means 2 sets the control mode of the drive wheels 24. Therefore, once the control mode is set, the driver does not tilt the directional switch 23 again. Since it is not changed as much as possible, the operability that the traveling direction of the forklift 21 can be changed only by operating the handle 25 is not impaired.
[0032]
Note that if the forklift is equipped with a backup battery other than the battery serving as the power source for the traveling motor 3 or the like, the control mode of the traveling motor 3 can be set even while the traveling motor 3 is powered off. Can be stored in the memory.
[0033]
In the above embodiment, the steering angle θ of the driving wheel 24 is detected by detecting the protrusion 38 on the steering gear 35 that rotates integrally with the driving wheel 24 by the limit switch 6. The steering angle θ may be detected using a reflection type optical sensor instead of the limit switch 6 by making the portion where the 38 is formed into a cavity penetrating vertically. That is, the steering angle θ of the drive wheel 24 can be detected based on whether the optical sensor can detect the reflected light when the light emitted from the optical sensor is reflected on the steering gear 35. Further, the detection of the steering angle θ of the driving wheel 24 is not limited to the steering gear 35, but the steering angle θ of the driving wheel 24 is indirectly detected by detecting the operation angle of the handle 25 using a potentiometer or the like, for example. Also good.
[0034]
In the above embodiment, a seated reach forklift is described as an example of the forklift 21 provided in the vehicle so that the drive wheels 24 can be steered 360 °. However, the present invention is not limited to the seated reach type forklift, but can also be applied to the standing type reach type forklift and other forklifts. It is good also as an operation lever provided so that inclination in the front-back direction was possible.
[0035]
【The invention's effect】
Even if the driver does not select the traveling direction in consideration of the steering angle of the current driving wheel, the driver can travel the forklift in the desired direction only by selecting the traveling direction with the traveling direction selecting means. In addition, since the forklift does not travel in the direction opposite to the direction of travel of the forklift intended by the driver, it is possible to prevent the forklift from accidentally colliding with a load or the like and to perform the work safely.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a travel drive system provided in a forklift according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view showing a main part of a forklift according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a steering angle of a forklift according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram showing a steering angle detection unit according to the embodiment of the present invention.
FIG. 5 is a flowchart for determining a control mode of the traveling motor according to the embodiment of the present invention.
FIG. 6 is a perspective view of a forklift provided with drive wheels capable of being steered by 360 ° as viewed from the front of the vehicle.
7 is an enlarged perspective view of the vicinity of the driver's seat of the forklift shown in FIG. 6 as viewed from the side of the vehicle.
FIG. 8 is an explanatory diagram showing a relationship between a steering angle and a rotation direction of a driving wheel and a traveling direction of a forklift.
FIG. 9 is an explanatory diagram showing a relationship between a steering angle and a rotation direction of a driving wheel and a traveling direction of a forklift.
FIG. 10 is an explanatory diagram showing a relationship between a steering angle and a rotation direction of a driving wheel and a traveling direction of a forklift.
FIG. 11 is an explanatory diagram showing a relationship between a steering angle and a rotation direction of a drive wheel and a traveling direction of a forklift.
FIG. 12 is an explanatory diagram showing a relationship between a steering angle and a rotation direction of a driving wheel and a traveling direction of a forklift.
[Explanation of symbols]
2 Travel control means 6 Limit switch (steering angle detection means)
21 Seated Reach Type Forklift 23 Directional Switch (Traveling Direction Selection Unit)
24 Drive wheel 38 Protrusion (steering angle detection means)

Claims (1)

In a forklift in which a driving wheel is provided so as to be steerable by 360 ° and the traveling direction of the vehicle body can be freely changed only by operating a handle, a traveling direction selecting means operated by a driver to select a traveling direction of the forklift, and the driving When the traveling direction is selected by the steering angle detecting means for detecting the steering angle of the wheel and the traveling direction selecting means, the rotational direction of the driving wheel is determined based on the traveling direction and the steering angle, and Travel control means for controlling the forklift to travel in the selected travel direction, the travel direction selection means can select either forward or reverse as the travel direction of the forklift, and the steering angle detection means, The steering angle of the driving wheel can be detected in a range of −180 ° to 180 ° with respect to the forward direction of the forklift. When the steering angle detection means detects a steering angle within ± 90 ° with respect to the forward direction of the forklift, and the forward direction is selected by the travel direction selection means, the rotation direction of the drive wheel is set to the normal rotation direction. In the state where the steering angle detection means detects a steering angle within ± 90 ° with respect to the forward direction of the forklift, when the reverse direction is selected by the travel direction selection means, the rotation direction of the drive wheel is changed. When the steering angle detection means detects a steering angle of 90 ° to 180 ° or −180 ° to −90 ° with respect to the forward direction of the forklift by the steering angle detection means, the forward direction is selected by the travel direction selection means. When this is done, the direction of rotation of the drive wheel is set to the reverse direction, and the steering angle detection means makes 90 ° to 180 ° or −180 ° with respect to the forward direction of the forklift. In a state where the steering angle of the al -90 ° is detected, when the reverse is selected by the traveling direction selecting means, forklift, characterized in that the direction of rotation of the drive wheel and forward direction.

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