JP2012148839A - Cargo handling control system and forklift including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cargo handling control system and a forklift including the same with improved operation feeling in cargo handling.SOLUTION: This cargo handling control system 1 includes a hydraulic cylinder 8 for causing a cargo handling member to handle cargo, a hydraulic motor 5 driving a hydraulic pump 6 supplying hydraulic oil to the hydraulic cylinder 8, and control means 3 for controlling the hydraulic motor 5. The control means 3 controls the hydraulic motor 5 on the basis of a control command value function including, as control command value functions, at least, a first control command value function for increasing a control command value of the hydraulic motor 5 from a minimum control command value to a start control command value for starting the hydraulic cylinder 8 in a time domain from immediately after operation start of a cargo handling operation lever 2 to the start of the hydraulic cylinder 8, and a second control command value function for increasing the control command value of the hydraulic motor 5 from the start control command value toward a maximum control command value in a time domain after the start of the hydraulic cylinder 8.

Description

  The present invention relates to a cargo handling control system and a forklift equipped with the same, and more specifically, drives a hydraulic pump by controlling a hydraulic motor based on a preset control command value function associated with operation of a cargo handling lever. In addition, the present invention relates to a cargo handling control system that supplies hydraulic oil to a hydraulic cylinder and causes a cargo handling member to perform a cargo handling operation, and a forklift equipped with the cargo handling control system.

  Conventionally, a forklift drives a hydraulic pump by controlling a hydraulic motor based on a preset control command value function (for example, a rotation speed command value function, etc.) associated with operation of a cargo handling operation lever such as a lift operation lever. And a cargo handling control system that supplies hydraulic oil to a hydraulic cylinder such as a lift cylinder and causes a cargo handling member such as a fork to perform a predetermined cargo handling operation (for example, a lifting operation).

として与えられる。すなわち、この回転数指令値関数Ｎ（ｔ）は、油圧モータの回転数指令値が最小回転数指令値Ｓから最大回転数指令値（最大制御指令値）Ｎｍまで一定の傾きＭで上昇するような一次関数からなる。なお、同図において、Ｒは、後述するような、リフトシリンダ（油圧シリンダ）が始動する始動回転数指令値（始動制御指令値）である。また、Ｎｍは、最終目標値である最大回転数指令値（最大制御指令値）である。 FIG. 8A is a graph showing a rotational speed command value function in this conventional cargo handling control system. In the graph of FIG. 8A, the horizontal axis represents time, and the vertical axis represents the rotation speed command value N (t). FIG. 8B is a graph showing a moving speed-time characteristic of a cargo handling member that is caused to perform a cargo handling operation based on the rotation speed command value function of FIG. In the graph of FIG. 8B, the horizontal axis represents time, and the vertical axis represents the moving speed v (t) of the cargo handling member.
As shown in FIG. 8A, the rotation speed command value function N (t) in the conventional cargo handling control system is expressed by the following equation:

As given. That is, the rotational speed command value function N (t) is such that the rotational speed command value of the hydraulic motor increases with a constant slope M from the minimum rotational speed command value S to the maximum rotational speed command value (maximum control command value) Nm. It consists of a linear function. In the figure, R is a starting rotational speed command value (starting control command value) for starting a lift cylinder (hydraulic cylinder) as will be described later. Nm is a maximum rotational speed command value (maximum control command value) that is a final target value.

By the way, in this cargo handling control system, due to the characteristics of a hydraulic pump or the like, a predetermined delay time is generated from the start of operation of the cargo handling lever until the hydraulic cylinder is actually started.
That is, as shown in FIG. 8 (A), when the lift operating lever is operated by the operator at time t = 0, the rotational speed command value function N (t) is minimum rotated after a predetermined delay time Δt = td. From the numerical command value S, the starting rotational speed command value R rises to R = M × td + S. Based on this function, the rotational speed of the hydraulic motor reaches from S to R. During this time, the lift cylinder is in a non-operating state, and the moving speed of the cargo handling member remains 0 as shown in FIG. 8B (see the time domain from time t = 0 to t = td).
When the lift cylinder starts at time t = td, after the time (tm−td) has elapsed, the rotational speed command value function N (t) changes from the starting rotational speed command value R to the maximum rotational speed command value Nm = M × tm + S. Based on this function, the rotational speed of the hydraulic motor reaches from R to Nm. During this time, the lift cylinder is in an operating state, and as shown in FIG. 8B, the moving speed v (t) of the cargo handling member increases in proportion to the increase in the rotational speed command value N (t), and the cargo handling member is constant. (See time domain from time t = td to t = tm).

However, since the conventional rotational speed command value function N (t) has only a linear function with an inclination of M and an intercept of S, a delay time from the start of the operation of the cargo handling operation lever to the actual operation of the hydraulic cylinder (Hereinafter referred to as “response time”) and the acceleration of the cargo handling member are uniquely determined by this function. That is, the conventional cargo handling control system has a problem that the response time and acceleration cannot be freely changed to meet the operator's request.
Generally, in order to vary the response time and acceleration to some extent, a method of varying the slope M in the above equation (1) can be considered. However, this has the following problems.

FIG. 9A is a graph showing a rotational speed command value function when the intercept S is constant and only the slope is Ma, M, and Mb (where Mb <M <Ma), and FIG. It is a graph which shows the time characteristic of each moving speed of a cargo handling member, (C) summarizes the relationship between response time and acceleration when based on each rotation speed command value function of (A). In addition to making the inclination M variable, it is conceivable to change the minimum rotational speed command value S, but this S is generally used to adjust mechanical play and backlash of each part in the cargo handling control system. Therefore, description of the point where S is varied is omitted.
As shown in FIGS. 9A to 9C, when <1> rotation speed command value function N (t) = Ma × t + S, <2> rotation speed command value function N (t) = M × Since the inclination is larger than t + S, the response time Δt = tda is short and the acceleration is large. On the other hand, when the rotational speed command value function N (t) = Mb × t + S in <3> is smaller than the rotational speed command value function N (t) = M × t + S in <2>, the response time Δt = tdb is long and the acceleration is small.

  However, even if the inclination M is varied in this way, the response time cannot be shortened and the acceleration cannot be reduced. Similarly, the response time is long and the acceleration cannot be increased. Thus, in the conventional cargo handling control system, it has been difficult to make a clear difference between response time and acceleration. For this reason, there has been a problem that the operational feeling in the cargo handling work of the forklift meeting the operator's request cannot be realized sufficiently.

  The present invention has been made in view of such circumstances, and provides a cargo handling control system and a forklift equipped with the cargo handling control system that further improve the operational feeling in cargo handling work.

In order to solve the above problems, the present invention provides a hydraulic cylinder for causing a cargo handling member to perform a cargo handling operation, a hydraulic motor that drives a hydraulic pump that supplies hydraulic oil to the hydraulic cylinder, and a cargo handling corresponding to the cargo handling operation. Control means for controlling the hydraulic motor based on a preset control command value function such that the control command value of the hydraulic motor rises from the minimum control command value to the maximum control command value in accordance with the operation of the operation lever; The control means includes, as the control command value function, at least in a time region from the start of operation of the cargo handling lever to the start of the hydraulic cylinder as the control command value function. A first control command value function in which a control command value increases from the minimum control command value to a start control command value for starting the hydraulic cylinder; A control command value including a second control command value function in which a control command value of the hydraulic motor rises from the start control command value toward the maximum control command value in a time region after the start of the pressure cylinder The cargo handling control system is characterized in that the hydraulic motor is controlled based on a function.
According to this invention, at least the first control command value function and the first control command value function in the time region immediately after the start of operation of the cargo handling lever until the hydraulic cylinder starts and the time region after the hydraulic cylinder starts, The two control command value functions are configured separately. Therefore, the first control command value function can freely vary the time from the start of operation of the cargo handling lever to the start of the hydraulic cylinder, and the second control command value function allows the state after the hydraulic cylinder is started. Therefore, the operational feeling in cargo handling work can be improved by various combinations of these functions.

として、与えられ、
前記第２の制御指令値関数は、Ｎ２（ｔ）として、次式、

として、与えられることが好ましい。
この発明によれば、荷役操作レバーの操作開始直後から油圧シリンダが始動するまでの時間領域と、油圧シリンダの始動後の時間領域とにおいて、それぞれ一次関数からなる、第１の制御指令値関数Ｎ１（ｔ）と、第２の制御指令値関数Ｎ２（ｔ）とが別々に構成されている。したがって、第１の制御指令値関数Ｎ１（ｔ）の傾きＭ１等を可変することによって、荷役操作レバーの操作開始直後から油圧シリンダが始動するまでの時間を自由に可変できるとともに、第２の制御指令値関数の傾きＭ２等を可変することによって、油圧シリンダの始動後の状態を自由に可変できるので、これらの一次関数の様々な組合せによって、より簡単な構成で、荷役作業における操作フィーリングを向上させることができる。 In the above configuration, the first control command value function is expressed as the following equation as N1 (t):

As given and
The second control command value function is expressed by the following equation as N2 (t):

Is preferably given as
According to the present invention, the first control command value function N1 is composed of a linear function in each of the time region from the start of operation of the cargo handling lever to the start of the hydraulic cylinder and the time region after the start of the hydraulic cylinder. (T) and the second control command value function N2 (t) are configured separately. Therefore, by changing the slope M1 and the like of the first control command value function N1 (t), the time from the start of operation of the cargo handling lever to the start of the hydraulic cylinder can be freely changed, and the second control By changing the slope M2 etc. of the command value function, the state after the start of the hydraulic cylinder can be freely changed. Therefore, various combinations of these linear functions can provide an operational feeling in cargo handling work with a simpler configuration. Can be improved.

Further, in the above configuration, the hydraulic motor is also used for each of the plurality of hydraulic cylinders that causes the cargo handling member to perform a plurality of cargo handling operations, and each of the hydraulic cylinders includes a control command value including a corresponding maximum control command value. When a function is set and a plurality of cargo handling operation levers corresponding to the plurality of cargo handling operations are simultaneously operated, the control means is configured to obtain the smallest maximum control command value set for each hydraulic cylinder. The hydraulic motor is preferably controlled based on a control command value function including a control command value.
In the cargo handling control system, a hydraulic motor is used for each of a plurality of hydraulic cylinders that cause a cargo handling member to perform a plurality of cargo handling operations, and a control command value function including a maximum control command value corresponding to each hydraulic cylinder is set. In this case, when a plurality of cargo handling operation levers corresponding to a plurality of cargo handling operations are simultaneously operated, the hydraulic cylinder may suddenly operate unexpectedly depending on the maximum control command value.
Therefore, according to the present invention, the control means is configured to control the hydraulic motor based on the control command value function including the smallest maximum control command value among the maximum control command values set for each hydraulic cylinder. Therefore, such a problem of sudden operation can be avoided.

Further, in the above configuration, the display unit is further provided with a display unit capable of selecting the first and second control command value functions according to an operator's preference, and the control means is selected from the display unit by the operator. It is preferable to control the hydraulic motor according to the first and second control command value functions.
According to the present invention, since the first and second control command value functions according to the operator's preference can be selected by the display unit, an operation feeling according to each operator's request is realized. be able to.

  Furthermore, the forklift can be provided with the cargo handling control system configured as described above.

  According to the present invention, it is possible to provide a cargo handling control system and a forklift equipped with the cargo handling control system with further improved operational feeling.

It is a block diagram which shows one Example of the cargo handling control system which concerns on this invention. It is a side view of the forklift provided with the cargo handling control system of FIG. (A) is a graph which shows the rotation speed command value function in the cargo handling control system of FIG. 1, (B) is a graph which shows the time characteristic of the moving speed of a cargo handling member. (A) is that the response time Δt = tdLa in the first rotation speed command value function is constant, and the slopes of the second rotation speed command value function are ML2a, ML2, ML2b (where ML2b <ML2 <ML2a), respectively. (B) is a graph showing the rotation speed command value function when the response time Δt = tdL in the first rotation speed command value function is constant, and the slope of the second rotation speed command value function is ML2a. , ML2 and ML2b are graphs showing the rotation speed command value function, (C) is a second rotation speed command value function with a constant response time Δt = tdLb in the first rotation speed command value function. Is a graph showing a rotational speed command value function when the slope of each is ML2a, ML2, ML2b, and (D) is a response time when based on each rotational speed command value function of (A) to (C) And acceleration It summarizes the relationship. 1 shows an application example of a cargo handling control system according to the present invention, in which (A) is a graph showing a rotation speed command value function for lift cylinder operation, and (B) is a rotation speed command for tilt cylinder operation. It is a graph which shows a value function, (C) is a graph which shows the rotation speed command value function for reach cylinder operation | movement. It is a flowchart explaining operation | movement of the cargo handling control system based on each rotation speed command value of FIG. 5 (A) and (B). The modification example of the cargo handling control system which concerns on this invention is shown, (A) is a graph which shows the 1st modification of a rotation speed command value function, (B) is a movement of the cargo handling member of (A). It is a graph which shows the time characteristic of speed, (C) is a graph which shows the 2nd modification of a rotation speed command value function. (A) is a graph which shows the rotation speed command value function in the conventional cargo handling control system, (B) is a graph which shows the time characteristic of the moving speed of the cargo handling member of (A). (A) is a graph showing the rotational speed command value function when the intercept S is constant and only the slopes are Ma, M, and Mb (where Mb <M <Ma), and (B) is (A) ) Is a graph showing the time characteristics of the respective moving speeds of the cargo handling member, and (C) is a summary of the relationship between the response time and the acceleration when based on the respective rotation speed command value functions of (A).

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Example)
1 to 4 show an embodiment of the present invention.
The cargo handling control system 1 according to the present invention has a control command value function (described later) that is set in advance in accordance with the operation of at least one cargo handling operation lever 2 (lift operation lever 2L, tilt operation lever 2T, reach operation lever 2R, etc.). For example, the hydraulic pump 5 is driven by controlling the hydraulic motor 5 based on the rotation speed command value function, etc., and operates on at least one hydraulic cylinder 8 (lift cylinder 8L, tilt cylinder 8T, reach cylinder 8R, etc.). Oil is supplied, and a cargo handling operation (elevating motion, tilting motion, horizontal motion, etc.) is performed on a cargo handling member such as a pair of forks 15. The control command value function includes at least a control command value function including a first control command value function and a second control command value function. The first control command value function is that the control command value of the hydraulic motor 5 starts from the minimum control command value to start the hydraulic cylinder 8 in the time region immediately after the operation of the cargo handling operation lever 2 starts and until the hydraulic cylinder 8 starts. This function increases to the control command value. The second control command value function is a function such that the control command value of the hydraulic motor 5 increases from the start control command value toward the maximum control command value in the time domain after the hydraulic cylinder 8 is started.

The cargo handling control system 1 is provided, for example, in a forklift 10 as shown in FIG.
In this embodiment, in order to simplify the description, a case where the fork 15 is caused to move up and down based on the rotation speed command value function NL (t) associated with the operation of the lift operation lever 2L among the cargo handling operation levers 2 will be described. To do.

As shown in FIG. 1, the cargo handling control system 1 includes a lift cylinder 8 </ b> L that causes the fork 15 to move up and down, a hydraulic motor 5, and a control unit 3.
The hydraulic motor 5 drives a hydraulic pump 6 that supplies hydraulic oil for the tank 7 to the lift cylinder 8L. In addition, a lift control valve 9L composed of, for example, a proportional control valve is provided in a pipe line between the hydraulic pump 6 and the lift cylinder 8L.
The control means 3 includes a central processing unit (CPU) 3A, inverter control means 3B, and storage means (not shown) such as a memory. The CPU 3 </ b> A receives the output of the cargo handling operation lever 2 and the display unit 4 and controls the hydraulic motor 5 and the control valve 9. The inverter control means 3B controls the hydraulic motor 8 based on a control command from the CPU 3A accompanying the operation of the cargo handling operation lever 2, that is, a control command value function (for example, a rotation speed command value function).
In this embodiment, the inverter control means 3B controls the hydraulic motor 5 on the basis of the rotation speed command value function NL (t) set in advance with the operation of the lift operation lever 2L. The rotational speed command value function NL (t) is stored in advance in the storage means of the control means 3. Further, the CPU 3A controls the lift control valve 9L so that the lift control valve 9L has a constant opening while the lift operation lever 2L is being operated.

である。
第２の回転数指令値関数ＮＬ２（ｔ）は、リフトシリンダ８Ｌの始動後の時間領域において、油圧モータ５の回転数指令値が始動回転数指令値ＲＬから最大回転数指令値ＮｍＬまで一定の傾きＭＬ２で上昇するような関数であり、次式で与えられる。すなわち、

である。 In this embodiment, the rotational speed command value function NL (t) is, as shown in FIG. 3A, the first rotational speed command value function NL1 (t) and the second rotational speed command value function NL2 (t ).
The first rotation speed command value function NL1 (t) indicates that the rotation speed command value of the hydraulic motor 5 is the minimum rotation speed command value SL in the time domain immediately after the operation of the lift operation lever 2L is started until the lift cylinder 8L starts. To a starting rotational speed command value RL at which the lift cylinder 8L starts, a function that increases at a constant slope ML1 and is given by the following equation. That is,

It is.
The second rotational speed command value function NL2 (t) indicates that the rotational speed command value of the hydraulic motor 5 is constant from the starting rotational speed command value RL to the maximum rotational speed command value NmL in the time region after the start of the lift cylinder 8L. This is a function that rises with the slope ML2, and is given by the following equation. That is,

It is.

Next, operation | movement of the control means 3 of the cargo handling control system 1 of this invention is demonstrated easily below with reference to FIG.1 and FIG.3 (A) and (B).
As shown in FIG. 3A, when the lift operating lever 2L is operated by the operator at time t = 0, the rotational speed command value NL (t) becomes the minimum rotational speed command value after a predetermined delay time Δt = tdL has elapsed. The control means 3 controls the hydraulic motor 5 based on the first rotation speed command value function NL1 (t) that increases from SL to the starting rotation speed command value RL = ML1 × tdL + SL. At this time, the rotation speed of the hydraulic motor 5 reaches RL from SL. During this time, the lift cylinder 8L is in a non-operating state, and as shown in FIG. 3B, the moving speed of the fork 15 remains 0 (see the time domain from time t = 0 to t = tdL).
When the lift cylinder 8L starts at time t = tdL, the rotational speed command value NL (t) is changed from the starting rotational speed command value RL to the maximum rotational speed command value NmL = ML2 × (tmL− The control means 3 controls the hydraulic motor 5 based on the second rotation speed command value function NL2 (t) that rises to (tdL) + SL. At this time, the rotational speed of the hydraulic motor reaches NmL from RL. During this time, the lift cylinder 8L is in an operating state, and as shown in FIG. 3B, the moving speed vL (t) of the fork 15 increases in proportion to the increase in the second rotational speed command value function NL2 (t). The fork 15 moves up and down at a constant acceleration (see the time domain from time t = tdL to t = tmL).

(Effect of Example)
According to the present invention, at least in the time region from the start of operation of the cargo handling lever 2 such as the lift lever 2L to the start of the hydraulic cylinder 8 such as the lift cylinder 8L and the time region after the start of the hydraulic cylinder 8 The first control command value function and the second control command value function are configured separately. Accordingly, the first control command value function can freely vary the time from the start of operation of the cargo handling lever 2 to the start of the hydraulic cylinder 8, and the second control command value function can be used to start the hydraulic cylinder 8. Since the later state can be freely changed, various combinations of control command value functions as described below can be realized.

4A to 4C show the first rotation speed command value function NL1 (t) when the intercept SL is constant and only the slopes are ML1a, ML1, and ML1b (where ML1b <ML1 <ML1a), respectively. And a second rotational speed command value function NL2 (t) when the intercept RL is constant and only the slope is ML2a, ML2, ML2b (where ML2b <ML2 <ML2a), respectively. It is a graph which shows NL (t). FIG. 4D summarizes the relationship between response time and acceleration when based on each rotation speed command value function NL (t) in FIGS.
As can be seen from FIGS. 4A to 4D, in the case of the rotational speed command value function NL (t) of <A-1>, the response time Δt in the first rotational speed command value function is tdLa, and Since the slope in the second rotation speed command value function is ML2a, the response time is shorter and the acceleration is larger than the rotation speed command value function NL (t) of <B-2>. Similarly, in the case of the rotational speed command value function NL (t) of <A-3>, the response time Δt in the first rotational speed command value function is tdLa, and the slope in the second rotational speed command value function is Since it is ML2b, the response time is shorter and the acceleration is smaller than the rotation speed command value function NL (t) of <B-2>. In the same manner, various combinations of the first and second rotational speed command value functions NL1 (t) and NL2 (t) are realized. As shown in FIG. You can make a difference. Therefore, according to this cargo handling control system 1, the operation feeling in cargo handling work can be further improved compared to the conventional one.

(Application 1)
Each application example of the cargo handling control system of the present invention will be described with reference to FIGS. 1, 2, and 4 to 6.
The cargo handling control system according to Application Example 1 differs from that described in the above embodiment in that a control command value function is set for each of a plurality of hydraulic cylinders that also serve as a hydraulic motor. Therefore, only this different point will be described.

As shown in FIGS. 1, 2, and 5 (A) to 5 (C), this cargo handling control system 1 includes a tilt cylinder 8T that causes the fork 15 to perform a tilting operation and a horizontal operation, in addition to the lift cylinder 8L, and reach. A cylinder 8R.
In addition to the lift cylinder 8L, the hydraulic motor 5 drives a hydraulic pump 6 that supplies hydraulic oil in the tank 7 to the tilt cylinder 8T and the reach cylinder 8R. A tilt control valve 9L and a reach control valve 9R are provided on the pipe line between the hydraulic pump 6 and the tilt cylinder 8T and the pipe line between the hydraulic pump 6 and the reach cylinder 8R, respectively.
The inverter control means 3B is based on rotation speed command value functions NL (t), NT (t), NR (t) set in advance with each operation of the lift operation lever 2L, the tilt operation lever 2T, and the reach operation lever 2R. Then, the hydraulic motor 5 is controlled. These rotational speed command value functions NL (t), NT (t), NR (t) are stored in advance in the storage means of the control means 3.

  The rotational speed command value function NL (t) corresponding to the operation of the lift cylinder 2L is a first and second rotational speed command value function NL1 (t) which are both linear functions as shown in FIG. , NL2 (t). As shown in FIG. 5B, the rotation speed command value function NT (t) corresponding to the operation of the tilt cylinder 2T is a first and second rotation speed command value function NT1 (t), both of which are linear functions. , NT2 (t). The rotational speed command value function NR (t) corresponding to the operation of the reach cylinder 2R is a first and second rotational speed command value function NR1 (t), both of which are linear functions, as shown in FIG. , NR2 (t).

Next, in the cargo handling control system 1 according to the application example 1, the operation of the control means 3 when a plurality of cargo handling operation levers (for example, the lift lever 2L and the tilt lever 2T) are simultaneously operated will be briefly described below. To do.
As shown in FIG. 6, the control means 3 first detects whether or not there is an operation of the lift operation lever 2L (see step S1 in FIG. 6). When the lift operation lever 2L is operated, the lift control valve 9L is opened to a certain opening (see step S2 in the figure), and further, it is detected whether or not the tilt operation lever 2T is operated. (Refer to step S3 in the figure). When the tilt control lever 2T is operated, the tilt control valve 9T is opened to a constant opening (see step S4 in the figure), and the rotation speed command value functions corresponding to the lift cylinder 8L and the tilt cylinder 8T, respectively. The hydraulic motor 5 is controlled based on the rotational speed command value function that includes the smallest maximum rotational speed command value (NmL or NmT, whichever is smaller) of NL (t) and NT (t) (same as above). (See step S5 in the figure).
Further, when there is no operation of the tilt operation lever 2T in step S3, the control means 3 controls the hydraulic motor 5 based on the rotational speed command value function NL (t) corresponding to the lift cylinder 8L (same figure). Step S6).
Further, when there is no operation of the lift operation lever 2L in step S1, the control means 3 detects whether or not there is an operation of the tilt operation lever 2T (see step S7 in the figure). When the tilt control lever 2T is operated, the tilt control valve 9T is opened to a certain opening (see step S8 in the figure), and the rotation speed command value function NT (t) corresponding to the tilt cylinder 8L is set. Based on this, the hydraulic motor 5 is controlled (see step S9 in the figure).

(Effect of application example 1)
In this cargo handling control system 1, the hydraulic motor 5 is also used for each of a plurality of hydraulic cylinders 8 that cause the cargo handling member 13 to perform a plurality of cargo handling operations, and includes a control command value including a maximum control command value corresponding to each hydraulic cylinder 8. When the functions NL (t), NT (t), and NR (t) are set, when the plurality of cargo handling operation levers 2 corresponding to the plurality of cargo handling operations are simultaneously operated, depending on the maximum control command value The hydraulic cylinder 8 may suddenly operate unexpectedly.
However, according to the present invention, the control means 3 controls the hydraulic motor 5 based on the control command value function including the smallest maximum control command value among the maximum control command values set for each hydraulic cylinder 8. Such a configuration makes it possible to avoid such a problem of sudden operation.

(Application example 2)
The cargo handling control system according to the application example 2 is different from that described in the above embodiment in that the cargo handling control system includes a display unit capable of selecting a control command value function according to the operator's preference. Therefore, only this different point will be described.

  As shown in FIG. 1, the cargo handling control system 1 includes a display unit 4. The display unit 4 is provided at, for example, a driver's seat that is easily visible to an operator who operates the forklift 10. For example, a screen showing a table as shown in FIG. 4D is displayed on the display unit 4, and a control command value function (combination of the first and second control command value functions) is selected according to the operator's preference. It is possible. When the operator selects a desired control command value function during cargo handling work by the forklift 10 (selects any one of modes 1 to 9), the control means 3 is based on the selected control command value function. The hydraulic motor 5 is controlled.

(Effect of application example 2)
According to the present invention, since the first and second control command value functions according to the operator's preference can be selected by the display unit, an operation feeling according to each operator's request is realized. be able to.

  As mentioned above, although preferable embodiment of this invention was described, the structure of this invention is not limited to these embodiment.

The control command value function is not limited to the above, and any function may be used as long as it includes at least a first control command value function and a second control command value function that are independent of each other. Good.
For example, as shown in FIG. 7A, the control command value function may be composed of at least three or more independent control command value functions. Further, as shown in FIG. 7B, the control command value function may be composed of a nonlinear function such as an n-order function (where n is a positive number of 2 or more), for example. In FIG. 7A, Ra is a starting rotational speed command value for starting the hydraulic cylinder 8.

The control means 3 may be configured to control the control command value of the hydraulic motor, for example, by PI control (proportional integration control) based on the control command value function.
Also, as the control command value (control command value function), in addition to the rotational speed command value (rotational speed command value function), the hydraulic motor current command value, speed command value (current command value function, speed command value function), etc. May be used.

  The cargo handling control system can also be applied to an electric vehicle other than a forklift, such as a crane that performs cargo handling work.

DESCRIPTION OF SYMBOLS 1 Handling control system 2 Handling operation lever 2L Lift operation lever 2T Tilt operation lever 2R Reach operation lever 3 Control means 3A CPU
3B Inverter control means 4 Display unit 5 Hydraulic motor 6 Hydraulic pump 7 Tank 8 Hydraulic cylinder 8L Lift cylinder 8T Tilt cylinder 8R Reach cylinder 9 Control valve 9L Lift control valve 9T Tilt control valve 9R Reach control valve 10 Forklift 11 Driver's seat 12 Vehicle body 13 Mast 14 Bracket 15 Fork S1-S9 Step

Claims (5)

A hydraulic cylinder for causing the cargo handling member to perform a cargo handling operation;
A hydraulic motor that drives a hydraulic pump that supplies hydraulic oil to the hydraulic cylinder;
Based on a preset control command value function such that the control command value of the hydraulic motor increases from the minimum control command value to the maximum control command value in accordance with the operation of the cargo handling operation lever corresponding to the cargo handling operation. A cargo handling control system comprising a control means for controlling a motor,
The control means at least as the control command value function,
The control command value of the hydraulic motor rises from the minimum control command value to the start control command value for starting the hydraulic cylinder in the time domain from the start of operation of the cargo handling lever to the start of the hydraulic cylinder. A first control command value function;
A control command value function including a second control command value function in which a control command value of the hydraulic motor increases from the start control command value toward the maximum control command value in a time region after the start of the hydraulic cylinder. A cargo handling control system that controls the hydraulic motor based on a value function. The first control command value function is represented by the following equation as N1 (t):

As given and
The second control command value function is expressed by the following equation as N2 (t):

The cargo handling control system according to claim 1, wherein The hydraulic motor is also used for each of the plurality of hydraulic cylinders for causing the cargo handling member to perform a plurality of cargo handling operations,
A control command value function including a corresponding maximum control command value is set for each hydraulic cylinder,
When a plurality of cargo handling operation levers corresponding to the plurality of cargo handling operations are operated simultaneously,
The control means controls the hydraulic motor based on a control command value function including the smallest maximum control command value among the maximum control command values set for each hydraulic cylinder. Or the cargo handling control system of 2. A display unit capable of selecting the first and second control command value functions according to operator preference;
The said control means controls the said hydraulic motor according to the said 1st and 2nd control command value function selected by the said operator from the said display part, The any one of Claims 1-3 characterized by the above-mentioned. The cargo handling control system described.   The forklift provided with the cargo handling control system in any one of Claims 1-4.

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