JPS61105225A - Clutch control device in industrial vehicles - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to industrial vehicles such as forklifts, and more particularly to a clutch control device that controls clutch engagement.

(Prior Art) In industrial vehicles with automatic transmissions that are directly connected to the engine without a torque converter, the clutch is disengaged when the engine speed decreases.

The timing for disengaging the clutch is to completely disengage the clutch when the engine speed drops to a predetermined speed, and the clutch remains connected until the engine speed drops to the predetermined speed. It was kept fully connected.

(Problems to be Solved by the Invention) However, if the clutch is completely disengaged when the engine speed drops to a predetermined speed, the torque will suddenly be cut off. Therefore, if the torque is cut off while the vehicle is climbing a slope, there is a risk that the vehicle will back up, creating a problem.

The purpose of this invention is to control the connection state of the clutch without completely disengaging the clutch even if the engine speed drops below a certain level, thereby solving the conventional problem caused by sudden loss of torque due to a drop in engine speed. An object of the present invention is to provide a clutch control device for an industrial vehicle that can solve the problems and improve operability.

Structure of the Invention (Means for Solving Problems) In order to achieve the above object, the present invention includes a clutch that turns on and off the output of an engine and transmits the output to an automatic transmission, and a clutch that operates the clutch and transmits the output to an automatic transmission. a clutch driving means for controlling the engagement state of the clutch; a rotation speed detector for detecting the rotation speed of the engine; a clutch detector for detecting the engagement state of the clutch; a storage device for storing connection data; a reading means for determining a current engine rotation speed based on the rotation speed detector and reading connection data corresponding to the rotation speed from the storage device; and the read connection data and the clutch. The gist thereof is a clutch control device for an industrial vehicle, comprising a control means for driving the clutch driving means and controlling the clutch to a predetermined connected state based on the current clutch connected state detected by a detector. be.

(Function) When the vehicle is running, the reading means determines the current engine rotation speed based on the detection signal from the rotation speed detector. Next, the reading means reads connection data corresponding to the determined engine speed from a storage device that stores clutch connection data with respect to the engine speed. Based on the read connection data, the control means drives the clutch drive means to control the clutch to a predetermined connected state.

(Embodiment) Hereinafter, a preferred embodiment in which the present invention is embodied in a forklift will be described with reference to the drawings.

In Figure 1, the output of engine 1 is equal to the output of dry single plate clutch 2.
The signal is transmitted to the automatic transmission 3 via the differential gear mechanism 4, and the automatic transmission 3 drives the traveling drive wheels 5 forward and backward at a predetermined gear ratio.

The dry single plate clutch 2 that turns on and off the output of the engine 1 has its connection state adjusted relative to the stroke amount of the extending rod 6a based on the drive of a clutch control actuator 6 as a clutch drive means. Ru.

The engine 1 is also used as a drive source for a hydraulic pump that supplies hydraulic oil to a lift cylinder for raising and lowering the fork and a tilt cylinder for tilting the mast.

An engine rotation speed sensor 7 serving as a rotation speed detector detects the rotation speed of the output shaft of the engine 1 and outputs the detection signal to the input/output interface 8.

The stroke detection sensor 9 as a clutch detector is composed of a potentiometer and detects the stroke of the rod 6a of the clutch control actuator 6, and the detection signal is converted into a digital signal by the A/D converter 10 and sent to the interface 8. is output to.

The accelerator opening sensor 11, which serves as an accelerator opening detector, is composed of a potentiometer and detects the amount of depression of the accelerator pedal 12 provided at the driver's seat.The detected signal is converted into a digital signal by the A10 converter 13 and sent to the interface. 8 is output.

The brake detection sensor 14 is provided in the driver's seat, detects whether or not the brake pedal 15 is depressed, and outputs a detection signal of the pedal depression to the interface 8.

The vehicle speed sensor 16 detects the rotational speed of the output shaft of the automatic transmission 3 and outputs the detection signal to the interface 8.

A central processing unit (hereinafter referred to as CPU) 17 serving as a reading means and a control means operates according to a control program stored in a read-only memory (hereinafter referred to as ROM) 18 as a storage device, and performs processing via the input/output interface 8. Detection signals from each of the sensors are input.

The CPU 17 determines the amount of depression of the accelerator pedal 12 based on the detection signal from the accelerator opening sensor 11.

Then, the CPU 17 uses this determined accelerator pedal 12.
controls the opening degree of the engine throttle by driving a throttle actuator (not shown) based on the amount of depression of the engine;
The rotation speed of the engine 1 is controlled. Note that the throttle opening degree corresponding to the amount of depression of the accelerator pedal 12 is set in advance, and the data is stored in the ROM1.
It is stored in 8.

Further, the CPU 17 determines the running speed of the forklift at that time based on the detection signal from the vehicle speed sensor 16. The CPU 17 determines the stroke amount of the rod 6a of the clutch control actuator 6, that is, the connection state (connection degree) of the dry single-plate clutch 2, based on the detection signal from the stroke detection sensor 9.

Further, the CPU 17 determines the current engine speed based on the detection signal from the engine speed sensor 7, and determines the engaged state of the clutch 2 with respect to the determined engine speed, that is, the O-rad of the clutch control actuator 6. The stroke amount of 6a is calculated.

In this embodiment, the stroke amount S of the rod 6a with respect to the engine speed N is set to the relationship shown in FIG.
It is stored in OM18 in advance.

The rod 6a for the engine speed N shown in FIG.
The stroke amount S is a stroke f that completely connects the clutch 2 when the rotation speed N of the engine 1 reaches a predetermined rotation speed (hereinafter referred to as the first reference rotation speed) N1 or less.
From f1s1, the stroke lS becomes shorter in proportion to the decrease in the rotational speed N, that is, the degree of engagement of the dry single-plate clutch 2 decreases, and the rotational speed at which there is a risk of engine stalling (hereinafter referred to as the second When the rotation speed reaches N2 (referred to as the reference rotation speed), a constant stroke 182 is maintained thereafter. In this embodiment, the first reference rotational speed N1 is set to a rotational speed at which there is a risk that the engine 1 will stall if the dry single-plate clutch 2 is in a fully connected state.

Then, the CPU 17 determines the stroke amount calculated based on the stroke IIS calculated based on the connection data and the detection signal from the stroke detection sensor 9 when the engine rotation speed N is equal to or lower than the first reference rotation speed N1. The rod 6a of the clutch control actuator 6
whether there is a stroke "S" based on the connection data,
That is, it is determined whether the dry type single plate clutch 2 is in a predetermined connected state. If the Orad 6a is not at the stroke amount S based on the connection data, the CPU 17 outputs a drive signal to the input/output interface 8 and the actuator drive circuit 19 to drive the clutch control actuator 6 to make the stroke amount S based on the connection data. drive. Then, when a predetermined stroke amount (connection state) S is reached,
The CPU 17 stops driving the control actuator 6 to maintain the stroke amount S.

Further, when the rotation speed of the engine 1 is equal to or higher than the first reference rotation speed N1, the CPU 17 determines the optimum shift state for the current driving condition based on the detection signals from the vehicle speed sensor 16 and the accelerator opening sensor 11. And CPU1
7 switches the shift state of the automatic transmission 3 to 1st or 2nd speed based on the determined shift state. At this time of switching, the CPLJ 17 outputs a drive signal to the actuator drive direction 19 to drive the clutch control actuator 6 to disconnect the dry single plate clutch 2. Note that the speed change state for this running state is set in advance, and the speed change data is stored in the ROM1.
It is stored in 8.

Further, the CPtJ 17 determines whether or not the brake pedal 15 is depressed based on the detection signal from the brake detection sensor 14, and when it is determined that the pedal 15 is depressed, disables the connection control of the clutch 2 based on the connection data. When the engine speed N1 becomes equal to or lower than the first reference speed N1, a drive signal for immediately disengaging the clutch 2 is output to the actuator drive circuit 19, and the stroke amount S of the rod 6a is
is set to 83.

A readable and rewritable memory (hereinafter referred to as RAM) 20 is configured to temporarily store various calculation results of the CPU 17.

Next, the operation of the forklift constructed as described above will be explained.

Now, while the vehicle is running forward, the CPU 17 is calculating the rotation speed of the engine 1 at that time based on the detection signal from the engine rotation speed sensor 7. Then, when the rotation speed of the engine 1 falls below the first reference rotation speed N1,
As shown in FIG. 2, the CPU 17 stores connection data in the ROM 18 in which the stroke amount S is short in proportion to the decrease in the rotational speed N, that is, the degree of connection of the dry single-plate clutch 2 is decreased.
Read from. The CPL 117 compares the stroke amount S of the rod 6a determined based on this connection data with the current stroke amount determined based on the detection signal from the stroke detection sensor 9.

The CPU 17 then controls the clutch control actuator 6.
It is determined whether the rod 6a is at the stroke amount S based on the connection data, that is, whether the dry single-plate clutch 2 is in a predetermined connected state, and the clutch control actuator 6 is driven and controlled. When the rod 6a reaches a predetermined stroke amount S, the CPU 17 should maintain the stroke amount (stop driving the control actuator 6,
The dry single plate clutch 2 is brought into a predetermined connected state.

Therefore, as shown in FIG. 2, when the engine speed N decreases below N1, the dry single-plate clutch 2 decreases in the direction of disconnection (half-clutch state), and the engine speed N decreases to below N1. When the automatic transmission 3 is not completely disengaged (torque is transmitted to the automatic transmission 3).

Therefore, there is no risk of the forklift immediately backing up due to the torque being cut off while climbing up a slope, unlike in the prior art. Then, by depressing the brake pedal 15, the forklift can be reliably stopped on the spot. On the other hand, the CPU 17 uses the brake detection sensor 14
The stroke amount S of the rod 6a in response to the detection signal from
is set to 83 to completely disengage the dry single plate clutch 2 to prevent wear of the clutch disc.

As described above, in this embodiment, when the rotation speed of the engine 1 is in a low state below the first reference rotation speed N1, the connection state of the clutch 2 is controlled and the torque transmitted to the automatic transmission 3 is cut off. Therefore, there is no risk of the forklift backing up due to the torque being cut off while climbing a slope, unlike in the conventional case.

Furthermore, since the clutch 2 is kept connected in accordance with the rotational speed of the engine 1, hunting due to repeated connection and disconnection of torque can be prevented. Moreover, it is possible to recover the engine rotational speed and to effectively utilize the energy of the engine 1.

Next, a second embodiment embodying the present invention will be described. It should be noted that while the above embodiment controlled the connection state of the dry type single disc clutch 2, this embodiment controls the connection state of the wet type multiple disc clutch.

FIG. 3 shows a hydraulic and electrical block circuit diagram of a forklift. A clutch oil pump 21 is driven by an engine 22, and pressure fluid from the pump 21 is supplied to a regulator valve 23. This pressure fluid is then regulated to a constant pressure by the regulator valve 23 and supplied to the forward/reverse clutch switching valve 25 via the pressure control valve 24 .

The forward/reverse clutch switching valve 25 is turned on or off based on the operation of a clutch switching lever 26 provided at the driver's seat, and supplies pressure fluid to the forward/reverse clutch 27 to connect the forklift to drive the forklift forward or backward. Reverse clutch 2
Reference numeral 7 denotes a wet multi-disc clutch, the connection state of which is controlled by the hydraulic pressure of the supplied pressure fluid.

The pressure control valve 24 adjusts the pressure of the pressure fluid supplied to the forward/reverse clutch 27, and controls the forward/reverse clutch 27.
It is now possible to control the connection status of

The pressure fluid sent out from the regulator valve 23 is supplied to a wet multi-disc clutch (not shown) constituting an automatic transmission for 1st speed (low speed), 2nd speed (medium speed), and 3rd speed (high speed). I'm attached to it.

An engine rotation speed sensor 28 serving as a rotation speed detector detects the rotation speed of the output shaft of the engine 22 and outputs the detection signal to the input/output interface 29. The oil pressure sensor 30 as a clutch detector is composed of a pressure sensor and detects the hydraulic pressure of the pressure fluid supplied to the forward/reverse clutch 27 via the forward/reverse clutch switching valve 25, and outputs the detection signal to the interface 29. be done.

The accelerator opening sensor 31, which serves as an accelerator distance detector, is composed of a potentiometer and detects the amount of depression of an accelerator pedal 32 provided at the driver's seat, and the detection signal is converted into a digital signal by an A/D converter 33. It is output to the interface 29.

A brake detection sensor 34 is provided in the driver's seat, detects whether or not a brake pedal 35 is depressed, and outputs a detection signal of the pedal depression to the interface 29.

Central processing unit (CP) as reading means and control means
The LJ) 36 operates according to a control program stored in a read-only memory (hereinafter referred to as ROM) 37 as a storage device, and inputs detection signals from each of the sensors via the input/output interface 29.

The CPU 36 determines the amount of depression of the accelerator pedal 32 based on the detection signal from the accelerator opening sensor 31.

Then, the CPU 36 uses the determined accelerator pedal 32.
The throttle actuator is driven based on the amount of depression of the engine 2 to control the opening degree of the engine throttle.
It is designed to control the rotation speed of 2. Note that the throttle opening degree relative to the amount of depression of the accelerator pedal 32 is set in advance, and the data is stored in the ROM 37.

The CP (J36) determines the hydraulic pressure (hereinafter simply referred to as hydraulic pressure) supplied to the forward/reverse clutch 27 based on the detection signal from the oil pressure sensor 30, that is, the connection state of the wet multi-disc clutch 27.

Furthermore, CPtJ36 is the engine speed sensor 28.
The engine speed at that time is determined based on the detection signal from the clutch 2, and the clutch 2 is
7, that is, the hydraulic pressure to be supplied to the clutch 27. In this embodiment, the oil pressure P with respect to the engine speed N is set in the relationship shown in FIG. 4, and data for this (connection data) is stored in the ROM 37 in advance.

When the rotation speed N of the engine 22 reaches the first reference rotation speed N1 or less, the oil pressure P with respect to the engine rotation speed N shown in FIG. In other words, the degree of engagement of the forward/reverse clutch 27 decreases in proportion to the decrease in the hydraulic pressure P, which may cause the engine to stall.
When the reference rotation speed N2 is reached, the oil pressure P2 is kept constant from then on.

Then, the CPLJ 36 calculates the oil pressure P calculated based on the connection data when the engine rotation speed N is lower than the first reference rotation speed N1 and the oil pressure calculated at that time based on the detection signal from the oil pressure sensor 30. In comparison, pressure control valve '24
It is determined whether the hydraulic pressure fluid based on the connection data is supplied to the forward/reverse clutch 27, that is, whether the forward/reverse clutch 27 is in a predetermined connected state. If the hydraulic pressure of the pressure fluid is not the hydraulic pressure P based on the connection data, C
The PLI 36 adjusts the hydraulic pressure P based on the connection data (via the input/output interface 29 to the solenoid drive circuit 3).
8 to drive the pressure control valve 24 and control the excitation of three electromagnetic solenoids that control the oil pressure of the pressure fluid.

Further, the CPU 36 determines whether or not the brake pedal 35 is depressed based on the detection signal from the brake detection sensor 34, and when determining that the pedal 35 is depressed, disables the connection control of the clutch 27 based on the connection data. When the engine speed N becomes equal to or lower than the first reference speed N1, a drive signal for completely disengaging the clutch 27 is immediately output to the solenoid drive circuit 38, and the oil pressure P is set to P3.

A readable and rewritable memory (hereinafter referred to as RAM) 40 is configured to temporarily store various calculation results of the CPU 36.

Next, the operation of the forklift constructed as described above will be explained.

Currently, while the vehicle is traveling forward, the CPLJ 36 calculates the rotation speed of the engine 22 at that time based on the detection signal from the engine rotation speed sensor 28. Then, when the rotation speed of the engine 22 falls below the first reference rotation speed N1, the CPU 36 determines that the oil pressure P is small in proportion to the decrease in the rotation speed N, as shown in FIG. The connection data that decreases the degree of connection is stored in the ROM37.
Read it out completely. The CPU 36 compares the oil pressure P calculated based on this connection data with the current oil pressure calculated based on the detection signal from the oil pressure sensor 30.

Then, the CPU 36 determines whether the pressure control valve 24 is supplying the pressure fluid of the hydraulic pressure P based on the connection data to the forward/reverse clutch 27, that is, whether the forward/reverse clutch 27 is in a predetermined connected state, and then controls the electromagnetic solenoid. 39 is excited and driven to drive the pressure control valve 24 and bring the clutch 27 into a predetermined connected state.

Therefore, as shown in FIG. 4, as the engine speed N decreases, the forward/reverse clutch 27 decreases in the direction of being disconnected (half-clutch state).

Therefore, there is no risk of the forklift immediately backing up due to the loss of torque from the engine 22 while climbing up a slope, unlike in the prior art. And brake pedal 3
If you press 5, you can definitely stop the forklift on the spot.

On the other hand, the CPU 36 disengages the forward/reverse clutch 27 in response to the detection signal from the brake detection sensor 34.

In this way, in this embodiment, the engine 2 is
2 is in a low state below the first reference rotation speed N1, the connection state of the forward/reverse clutch 27 is controlled, and the torque transmitted to the automatic transmission is controlled without being cut off. There is no risk of the forklift backing up due to the torque being cut off while climbing up a slope, unlike in the prior art.

Similarly, since the forward/reverse clutch 27 is kept connected in accordance with the rotational speed of the engine 22, hunting due to repeated disconnection and disconnection of torque can be prevented. Moreover, it is possible to recover the engine rotational speed and to effectively utilize the energy of the engine 22.

Note that the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned embodiments, the stroke amount S or oil pressure P of the rod 6a of the clutch control actuator 6 with respect to the engine rotation speed N is as shown in FIG. Although control is performed according to the relationship shown in FIG. 4, it may be implemented with appropriate changes depending on various work objectives.

Effects of the Invention As described above, according to the present invention, even if the engine speed drops below a certain level, the connection state of the clutch is controlled without completely disengaging the clutch, and the torque transmitted to the automatic transmission is completely cut off. Since the forklift is controlled without any problem, there is no risk of the forklift backing up due to the torque being cut off while climbing up a slope as in the past, and hunting due to repeated torque disconnection can be prevented.
This has an excellent effect of being able to recover the engine speed and effectively utilizing the energy of the engine.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the drive system mechanism and its electric circuit of a forklift according to a first embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the stroke amount of the clutch control actuator rod and the engine speed. 3 are hydraulic and electrical circuit diagrams of a forklift truck according to a second embodiment of the present invention, and FIG. 4 is a diagram showing the relationship between the hydraulic pressure of pressure fluid and the engine speed. Engine 1, 22, dry single plate clutch 2, automatic transmission 3
, clutch control actuator 6, rod 6a, engine speed sensor 7.28, stroke detection sensor 9,
Brake detection sensor 14°34, accelerator opening sensor 1
6, accelerator pedal 17, CPU 17.36, ROM 1
8.37, pressure control valve 24, forward/reverse clutch 27, oil pressure sensor 30° Patent applicant Toyota Industries Corporation Fuji
Tsu Co., Ltd.

Claims (1)

[Scope of Claims] A clutch that turns on and off the output of the engine and transmits the output to an automatic transmission; a clutch driving means that operates the clutch and controls the connection state of the clutch; and a rotational speed of the engine. a clutch detector that detects the connection state of the clutch; a storage device that stores in advance the connection state of the clutch with respect to the engine speed as connection data; reading means for determining the engine speed at that time and reading out connection data for the engine speed from the storage device; and driving the clutch based on the read connection data and the clutch connection state at the time detected by the clutch detector. A clutch control device for an industrial vehicle, comprising: a control means for driving a means to control the clutch to a predetermined connected state.