JP2001020978A - Control device of hydraulic clutch and industrial vehicle furnished with the same control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a hydraulic clutch capable of precisely controlling supplying hydraulic pressure to a pressure chamber in consideration of an influence of centrifugal clutch pressure. SOLUTION: A clutch cover 9b defining a pressure chamber 9a of a retreating clutch 9 integrally rotates with an input shaft 3a. A control device 41 is furnished with a CPU 42 to control supplying hydraulic pressure to the pressure chamber 9a of this retreating clutch 9 through a solenoid control valve 11. The CPU 42 estimates centrifugal clutch pressure working from hydraulic oil in the pressure chamber 9a in accordance with centrifugal force following rotation of the input shaft 3a and sets set pressure of a retreating clutch valve 11 to make the retreating clutch 9 at desired engagement pressure in consideration of the centrifugal clutch pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic clutch control device in which a clutch cover forming a pressure receiving chamber rotates integrally with an input side, and a hydraulic pressure supplied to the pressure receiving chamber is controlled via an electromagnetic control valve. It is about. The present invention also relates to an industrial vehicle provided with such a hydraulic clutch control device.

[0002]

2. Description of the Related Art Hydraulic clutches are used in various fields. When classified according to the clutch cover, a separate type in which the clutch rotates relative to the input side (input shaft) in a disengaged state (disconnected state). And an integrated type that rotates integrally with the input side. Separate type is common, but due to the arrangement and assembly of various elements or members in the clutch cover, the integrated type may increase the design flexibility,
In some cases, an integrated clutch cover is used (see, for example, Japanese Patent Application Laid-Open No. 10-151974).

On the other hand, a hydraulic clutch uses a diesel engine, for example, as a drive source of an input shaft thereof, and is sometimes used for rotating a driven body such as a wheel by an output shaft. In this case, the rotation speed control of the object to be rotated
This is performed by controlling the hydraulic pressure supplied to the pressure receiving chamber defined by the clutch cover via an electromagnetic control valve and adjusting the clutch engagement pressure. A typical example of such an application is
It is an industrial vehicle such as a forklift.

[0004] The invention described in the above-mentioned Japanese Patent Application Laid-Open No. 10-151974 relates to a cargo handling and traveling control device for an industrial vehicle. According to the present invention, when a transmission provided with a torque converter, a hydraulic forward clutch and a reverse clutch is supplied with hydraulic pressure discharged from a clutch pump to a pressure receiving chamber of the forward clutch and stopped, and the hydraulic pressure is increased or decreased, A clutch control valve for acceleration / deceleration / reverse braking, and a clutch control valve for reverse acceleration / deceleration / forward braking for supplying and stopping the discharge pressure oil of the clutch pump to the pressure receiving chamber of the reverse clutch and increasing / decreasing the oil pressure. It has. During normal running, the engine speed is set based on the operation amount of the accelerator pedal. In addition, during loading / running (loading traveling), the engine speed is set based on the amount of operation of the loading / unloading lever, and the vehicle speed is set to the target vehicle speed based on the amount of operation of the accelerator pedal. The clutch pressure is controlled by increasing or decreasing the hydraulic pressure of the pressure receiving chamber of the forward clutch of the forward clutch and the reverse clutch using the clutch control valve and the clutch control valve for reverse acceleration / deceleration and forward braking. When braking is necessary, the clutch in the traveling direction is disconnected, and the braking control is performed by increasing or decreasing the hydraulic pressure of the pressure receiving chamber of the clutch on the opposite side in the traveling direction.

[0005]

However, in the above-mentioned integrated hydraulic clutch, when the input shaft is driven and the clutch cover rotates, the hydraulic oil in the pressure receiving chamber also rotates. A pressure called a centrifugal clutch pressure is generated by being pressed against the inner peripheral surface of the clutch cover. This centrifugal clutch pressure increases in proportion to the square of the rotation speed of the input shaft and the distance from the rotation center.

Therefore, when an integrated hydraulic clutch is employed, it is difficult to accurately control the hydraulic pressure in the pressure receiving chamber due to the influence of the centrifugal clutch pressure described above. In particular, when the input shaft, that is, the clutch cover is rotated at a high speed, the adverse effect of the centrifugal clutch pressure is large, and it is difficult to cope only with the control by the electromagnetic control valve.

Accordingly, a first object of the present invention is to provide a hydraulic clutch control device capable of accurately controlling the pressure of hydraulic oil in a pressure receiving chamber in consideration of the influence of a centrifugal clutch pressure. A second object of the present invention is to control the vehicle speed with high accuracy when the hydraulic clutch is used in a half-clutch state with the rotation speed of the input shaft being high and the engagement pressure is adjusted to control the vehicle speed. It is to provide an industrial vehicle that can be performed.

[0008]

In order to achieve the first object, according to the first aspect of the present invention, the clutch cover forming the pressure receiving chamber rotates integrally with the input side and the pressure receiving chamber is connected to the input side. A centrifugal clutch for controlling a hydraulic clutch whose supply oil pressure is controlled via an electromagnetic control valve, the centrifugal clutch estimating a centrifugal clutch pressure acting from hydraulic oil in the pressure receiving chamber based on a centrifugal force caused by rotation of the input side. Pressure estimation means;
Setting means for setting a set pressure of the electromagnetic control valve for setting the hydraulic clutch to a desired engagement pressure in consideration of the centrifugal clutch pressure.

According to another aspect of the present invention, there is provided a transmission having a hydraulic forward clutch and a reverse clutch for transmitting the output of an engine to driving wheels via a torque converter. An industrial vehicle that drives the drive wheels via a device and uses a clutch that is not the forward side of the two clutches as a clutch for braking, wherein at least one of the forward clutch and the reverse clutch is attached to at least one of the forward clutch and the reverse clutch. Use the described hydraulic clutch,
The control device according to claim 1 is provided for controlling the hydraulic clutch.

According to the third aspect of the present invention, the drive source for traveling and the drive source for cargo handling are shared by a single engine, and the output of the engine is transmitted to drive wheels via a torque converter. Equipped with a transmission equipped with a forward clutch and a reverse clutch of the type, during normal running, the forward clutch is fully engaged and controlled to the target engine speed corresponding to the operation amount of the accelerator operating means. Controls the target engine speed set based on the operation amount of the operation means, and controls the clutch engagement pressure so that the target vehicle speed corresponds to the operation amount of the accelerator operation means by adjusting the forward clutch pressure. 2. The industrial vehicle according to claim 1, wherein the hydraulic clutch according to claim 1 is used for at least one of the two clutches, and the hydraulic clutch according to claim 1 is used for controlling the hydraulic clutch. With a location.

According to a fourth aspect of the present invention, in the industrial vehicle according to the second or third aspect, the centrifugal clutch pressure estimating means estimates the centrifugal clutch pressure based on an engine speed.

According to the first aspect of the present invention, the centrifugal force acts on the hydraulic oil in the pressure receiving chamber of the clutch cover that rotates integrally with the input shaft, and the centrifugal clutch pressure acts on the clutch. The centrifugal clutch pressure estimating means estimates the centrifugal clutch pressure, and the setting means sets the hydraulic pressure supplied by the electromagnetic control valve in consideration of the centrifugal clutch pressure. Therefore, hydraulic oil of appropriate hydraulic pressure reduced by the centrifugal clutch pressure is supplied to the pressure receiving chamber.

According to the second aspect of the invention, the output of the engine is transmitted to the drive wheels via the torque converter and the transmission. Among the hydraulic forward clutch and the reverse clutch provided on the transmission, a clutch that is not on the forward side is used as a braking clutch. The braking force is controlled by adjusting the engagement pressure in the half-clutch state. When adjusting the braking force, an appropriate clutch pressure is obtained by taking into account the centrifugal clutch pressure.

According to a third aspect of the present invention, in the first aspect, the driving source for traveling and the driving source for cargo handling are shared by one engine, and the amount of operation of the cargo handling operation means during cargo handling traveling. The present invention is applied to an industrial vehicle that controls a target engine speed set based on the engine speed. During cargo handling, the vehicle speed is relatively low, but the engine speed is relatively high for cargo handling, and the clutch cover also rotates at a high revolution speed. When controlling the traveling side clutch pressure to control the vehicle speed to the target vehicle speed, an appropriate clutch pressure can be obtained in consideration of the centrifugal clutch pressure.

According to the fourth aspect of the present invention, the centrifugal clutch pressure is estimated using an engine speed detection function inherently provided in an industrial vehicle having an engine.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a forklift as an industrial vehicle will be described below with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

As shown in FIG. 1, the output shaft 1 of the engine 1
a is an input shaft 3 of a transmission 3 including a torque converter 2 including a pump impeller 2a, a turbine impeller 2b, and the like.
a, the output shaft 3b of the transmission 3 is connected via a differential 4 to an axle 5 having driving wheels 5a. Although not shown, the axle 5 can be provided with a service brake. The throttle actuator 7 is provided in the engine 1, and the throttle opening is adjusted by the operation of the throttle actuator 7 to adjust the rotation speed of the engine 1, that is, the rotation speed of the output shaft 1 a of the engine 1.

The transmission 3 includes the input shaft 3a as described above.
And an output shaft 3b. The input shaft 3a is provided with a forward clutch 8 and a reverse clutch 9 in addition to the torque converter 2. A gear train (not shown) is provided between the forward clutch 8 and the reverse clutch 9 and the output shaft 3b, respectively, and the input shaft 3a is connected via the clutches 8, 9 and the gear train.
Is transmitted to the output shaft 3b. A hydraulic clutch, a wet multi-plate clutch in this embodiment, is used for the two clutches 8 and 9, and the connection force (engagement force) of each clutch disk can be adjusted by the oil pressure in the pressure receiving chambers 8a and 9a. The connection force increases when the hydraulic pressure in the pressure receiving chambers 8a and 9a is increased.

In this embodiment, the clutch cover 8b defining the pressure receiving chamber 8a is connected to the input shaft 3a via an appropriate bearing.
The clutch cover 9b defining the pressure receiving chamber 9a is disposed so as to rotate integrally with the input shaft 3a as clearly shown in FIG. In the forward clutch 8 and the reverse clutch 9, the oil pressure in the pressure receiving chambers 8a and 9a is controlled by the hydraulic pressure supplied through the forward clutch valve 10 and the reverse clutch valve 11, respectively. The forward clutch valve 10 and the reverse clutch valve 11 are constituted by pressure control proportional solenoid valves whose opening degree is proportional to the amount of current supplied to the solenoid.

2, the upper half of the reverse clutch 9 is enlarged and shown in detail. The clutch cover 9b, which can be fixed around the input shaft 3a in a fixed state by an appropriate method, has one end closed and the other end open. The piston member 9d, which is cylindrical and is disposed in the pressure receiving chamber 9a, is slidably disposed around a cylindrical guide portion 9c extending in the axial direction from the closed end of the clutch cover 9b. . In this embodiment, a plurality of (only two discs) disks 9e are provided inside the cylindrical portion of the clutch cover 9b so as to be immovable in the radial direction and slidable in the axial direction. On the other hand, a plurality of disks 9h (only two disks are shown) are similarly immovable in the radial direction and slide in the axial direction on the spline portion of the gear member 9g rotatably held on the input shaft 3a via the bearing 9f. It is movably provided, and is arranged alternately with the above-mentioned disk 9e.
The gear member 9g is configured to be a part of a reverse gear train (not shown). Therefore, when the oil pressure in the pressure receiving chamber 9a increases, the piston member 9d is pushed rightward in FIG. 2 against the urging force of a spring (not shown), and the disc 9e,
The connection force between the 9hs increases. The space between the disks 9e and 9h is drawn wide for convenience of illustration.

In the transmission 3, a parking brake 12 is connected to and built into the output shaft 3b. The parking brake 12 includes a disk 12a that rotates integrally with the output shaft 3b, and a brake pad 12b that is provided so as not to rotate with respect to the output shaft 3b and to be movable in the thrust direction. The brake pad 12b is urged in a direction in which the brake pad 12b is pressed against the disk 12a by the spring force of a spring (not shown) to generate an engagement pressure for braking, and is applied by a hydraulic pressure supplied to the pressure receiving chamber 12c via the brake valve 13. The braking state is released. The cover 12d defining the pressure receiving chamber 12c does not rotate integrally with the output shaft 3b, similarly to the clutch cover 8b.

In FIG. 1, the torque converter 2 and the transmission 3
Although each of the valves 10, 11, and 13 is shown separately, these devices are incorporated in one housing to constitute an automatic transmission. A hydraulic pump (not shown) is incorporated in the automatic transmission, and the discharge oil of the hydraulic pump is supplied to a flow path (not shown) and each of the valves 10, 11, 1.
The pressure receiving chambers 8a, 9a, and 12c can be supplied to the pressure receiving chambers 3 through 3 respectively. The hydraulic pump is driven by a rotational force transmitted to the transmission 3 when the engine 1 rotates.

A gear 14 is provided on the output shaft 1a of the engine 1 so as to be integrally rotatable, and the rotation speed of the output shaft 1a is detected by an engine speed sensor 15 comprising a magnetic pickup. The engine speed sensor 15 outputs a pulse signal proportional to the speed of the output shaft 1a. Also, the transmission 3
The input shaft 3a is provided with a gear 1 immediately after the torque converter 2.
6 is provided so as to be integrally rotatable, and the rotational speed of the input shaft 3a is detected by a rotational speed sensor 17 composed of a magnetic pickup cooperating with the gear 16. The rotation speed sensor 17 outputs a pulse signal proportional to the rotation speed of the input shaft 3a. A gear 18 is provided on the output shaft 3b of the transmission 3 so as to be integrally rotatable, and the number of rotations of the output shaft 3b is detected by a vehicle speed sensor 19 as a vehicle speed detecting means comprising a magnetic pickup. The vehicle speed sensor 19 outputs a pulse signal proportional to the rotation speed of the output shaft 3b.

Hydraulic pump 2 driven by engine 1
0 on the discharge side of the fork 2 via a pipe (not shown) or the like.
A lift cylinder 22 that raises and lowers 1 and a tilt cylinder (not shown) that tilts the mast 23 are connected. The lift cylinder 22 is provided with a pressure sensor 24 for detecting the load of the fork 21. The pressure sensor 24 detects the oil pressure inside the lift cylinder 22 and outputs a detection signal corresponding to the load of the fork 21.

An accelerator pedal 25 as accelerator operating means, an inching pedal 26 as brake operating means, and a brake pedal 27 also as brake operating means are provided on the floor of the cab. The inching pedal 26 is used to bring the clutch into a half-engaged state (half-clutch state) when performing a slow operation of the forklift by manual operation while performing a cargo handling operation. When the brake pedal 27 is operated (depressed), the brake pedal 27 is moved to the inching pedal 2.
6 operates independently of the inching pedal 26 when the inching pedal 26 is operated (depressed).
6 and the brake pedal 27 can be interlocked. That is, the inching pedal 26 is moved (operated) independently of the brake pedal 27 until the inching position is reached and at the inching position, but after the inching position, the brake pedal 27 is moved to the inching pedal 2.
6 and move together.

An accelerator sensor 28 as an accelerator operation amount detecting means for detecting the operation amount of the accelerator pedal 25 includes:
A detection signal proportional to the operation amount of the accelerator pedal 25 is output. Whether or not the inching pedal 26 is at the inching position is detected by an inching switch 29. The operation amount of the brake pedal 27 is detected by a brake sensor 30 as a brake operation amount detecting means. The brake sensor 30 outputs a detection signal proportional to the operation amount of the brake pedal 27.

A shift lever 31 is provided at the front of the cab (not shown) as forward / reverse switching operation means. The shift switch 32 that detects the position of the shift lever 31 detects whether the shift lever 31 is in the forward position F, the reverse position R, or the neutral position N, and outputs a signal corresponding to each position. In the operator's cab, a loading / unloading lever 33 as a loading / unloading operation means for operating the lift cylinder 22 described above is arranged.
Is detected by the cargo operation amount sensor 34. An operating lever of the above-described tilt cylinder (not shown) is also provided in the operator cab.

Next, the aforementioned throttle actuator 7, forward clutch valve 10, reverse clutch valve 11
An electrical configuration for driving and controlling the brake valve 13 and the like will be described.

A control unit 41 for controlling the driving includes a central processing unit (hereinafter, referred to as a CPU) 42, which also functions as a clutch pressure estimating unit and a setting unit, a read only memory (ROM) 43, and a readable and rewritable memory. (R
AM) 44, and an input interface 45 and an output interface 46. In the ROM 43,
A program that sets the clutch on the traveling side to a fully engaged state (fully connected state) during normal traveling to control the target engine speed corresponding to the operation amount of the accelerator pedal 25, and is set based on the operation amount of the cargo handling lever 31 during cargo handling traveling. A program for controlling the target engine speed and controlling the clutch engagement pressure so that the target vehicle speed corresponds to the operation amount of the accelerator lever 25 by adjusting the clutch pressure on the traveling side,
In addition to a predetermined control program such as a program for setting the operation timing of the parking brake 12 and a program for estimating the centrifugal clutch pressure in the reverse clutch 9, various data required for executing the control program are stored. RAM4
4 temporarily stores the calculation result of the CPU 42. CPU
42 operates based on various control programs stored in the ROM 43.

The CPU 42 includes an engine speed sensor 1
5, connected so that output signals of the rotation speed sensor 17, the vehicle speed sensor 19, the inching switch 29, and the shift switch 32 are input via the input interface 45. The pressure sensor 24, the accelerator sensor 28, the brake sensor 30, and the cargo handling operation amount sensor 34
CPU via D converter and input interface 45
42.

The CPU 42 is connected to the throttle actuator 7, the forward clutch valve 10, the reverse clutch valve 11 and the brake valve 13 via an output interface 46 and a drive circuit (not shown), and is stored in the ROM 43. It operates according to various control programs, and outputs control command signals to the throttle actuator 7 and the valves 10, 11, and 13.

The ROM 43 has a map indicating the relationship between the operation amount of the accelerator pedal 25 during normal running and the throttle opening, a map indicating the relationship between the operation amount of the loading lever 33 and the throttle opening, and an accelerator pedal during the loading operation. And a map indicating the relationship between the target operation speed and the 25 operation amounts. The ROM 43 includes a forward clutch valve 10 and a reverse clutch valve 11 for bringing the forward clutch 8, ie, the forward clutch 8 during forward travel, and the reverse clutch 9 into the half-clutch state during reverse travel, during cargo handling and inching travel. The reference opening is stored.

The ROM 43 stores the amount of operation of the brake sensor 30 and the engagement pressure (connection pressure) of a clutch other than the clutch on the braking side, that is, the clutch on the forward side, of both clutches 8 and 9.
Is stored.

The ROM 43 stores a map shown in FIG. 3 showing the relationship between the rotational speed of the input shaft 3a and the centrifugal clutch pressure. The centrifugal clutch pressure is a pressure generated in the hydraulic oil by centrifugal force when the hydraulic oil in the pressure receiving chamber provided in the clutch cover that rotates integrally with the input shaft 3a rotates together with the clutch cover. Since this pressure also acts on the clutch disc, it is called a centrifugal clutch pressure. The centrifugal clutch pressure P is P = krω ² (k is a proportional coefficient), where r is the distance of the mass from the center of rotation and ω is the angular velocity of the mass.
Is represented by The map is created by performing a test operation in advance and determining the relationship between the angular velocity of the input shaft 3a and the centrifugal clutch pressure P.

In this embodiment, since the clutch cover 9b of the reverse clutch 9 rotates integrally with the input shaft 3a, the hydraulic oil in the pressure receiving chamber 9a also rotates. Therefore, when adjusting the engagement pressure of the reverse clutch 9, the CPU 42 sets the opening of the reverse clutch valve 11 in consideration of the centrifugal clutch pressure P.

The CPU 42 controls the clutch valve so that the clutch on the traveling side is fully engaged during normal running, and controls the throttle actuator 7 so that the target engine speed with respect to the operation amount of the accelerator pedal 25 is achieved.

The CPU 42 controls the throttle actuator 7 so that the throttle opening corresponds to the engine speed at which the hydraulic pressure required for the cargo handling operation can be secured during the cargo handling travel. Further, based on the shift signal of the shift switch 32, the CPU 42 sets the clutch corresponding to the traveling direction in which the shift lever 31 is operated to the half-clutch state, and sets the target vehicle speed corresponding to the operation amount of the accelerator pedal 25. , One of the two clutch valves 10 and 11 is controlled.

When controlling the clutch valve 11 of the reverse clutch 9 that rotates integrally with the input shaft 3a, the CPU 42 determines the above-mentioned angular velocity ω based on the rotation speed signal input from the rotation speed sensor 17 via the input interface 45. Calculated, the angular velocity / centrifugal clutch pressure map is read from the ROM 43, and an estimated value of the centrifugal clutch pressure P corresponding to the rotation speed detected by the rotation speed sensor 17 is calculated. Then, the clutch pressure is set to a value obtained by subtracting the centrifugal clutch pressure P from the necessary clutch pressure when the centrifugal clutch pressure is not considered, and the supply pressure to the reverse clutch 9 is adjusted.

Next, the operation of the above-configured device will be described. The engine 1 is rotated at an engine speed corresponding to the throttle opening. The rotation of the engine 1 drives the hydraulic pump 20 to enter a state in which hydraulic oil can be supplied to the lift cylinder 22. Also, the engine 1 of the same drive source
Is transmitted to the transmission 3 via the output shaft 1a and the torque converter 2.

When the shift lever 31 is operated to the neutral position N, both clutch valves 10 and 11 are connected to the pressure receiving chamber 8.
The clutches 8 and 9 are held in a disengaged state (disconnected state) while the hydraulic pressure is not supplied to the a and 9a, and the rotation of the engine 1 is not transmitted to the output shaft 3b of the transmission 3. When the shift lever 31 is operated to the forward position F, the forward clutch valve 10 is operated to be able to supply hydraulic pressure to the pressure receiving chamber 8a, the forward clutch 8 is engaged, and the rotation of the engine 1 is stopped. Through the output shaft 3b. When the shift lever 1 is operated to the reverse position R, the reverse clutch valve 11 is operated to be able to supply hydraulic pressure to the pressure receiving chamber 9a, the reverse clutch 9 is engaged, and the rotation of the engine 1 is stopped. Through the output shaft 3b.

When the brake pedal 27 is operated during traveling, the clutch on the braking side is engaged, and a braking force is obtained. When the brake pedal 27 is operated to the braking position, the CPU 42 controls the corresponding clutch valve so that the clutch on the braking side is also engaged. The engagement pressure of the clutch is controlled to a value corresponding to the operation amount of the brake pedal 25.

When the CPU 42 determines that the vehicle speed is equal to or less than the stop vehicle speed and that the state in which the brake operation signal is input has continued for a predetermined time (for example, about 0.5 seconds), the CPU 42 outputs a brake command signal to the brake valve 13. I do. When the braking command signal is output, the hydraulic pressure is not supplied to the pressure receiving chamber 12c, the brake pad 12b is disposed at a braking position where the brake pad 12b is pressed against the disk 12a by a spring force, and the parking brake 12 is brought into a braking state. Therefore, when the driver operates the brake pedal 27 or the inching pedal 26 to stop the forklift, the parking brake 12 is automatically switched from the brake release state to the braking state with the forklift stopped. Parking brake 12
When the accelerator pedal 25 is operated, the braking state is released.

At the time of cargo handling traveling, the CPU 42
3 is read, and the throttle actuator 7 is controlled so that the target engine speed is set based on the operation amount of the cargo handling lever 33, and the clutch valve corresponding to the clutch on the traveling side is controlled. The clutch engagement pressure is controlled so that the target vehicle speed corresponds to the operation amount of the accelerator lever 25.

The engine 1 is used for both driving of the hydraulic pump 20 and driving of the drive wheels 5a. During loading and running, the engine 1 is required to rotate at high speed for loading and unloading, but the vehicle speed is low. Therefore, in order to achieve the target vehicle speed, it is necessary to control the clutch engagement pressure to be low and to control it with high accuracy. In the reverse clutch 9, the clutch cover 9b rotates at a high speed integrally with the input shaft 3a, and a centrifugal force acts on the hydraulic oil in the pressure receiving chamber 9a to generate a centrifugal clutch pressure P. It becomes larger than the engagement pressure based on the hydraulic pressure supplied from. As a result, for example, the vehicle speed may be higher than the target vehicle speed, or the industrial vehicle may not stop even though the clutch should be disengaged.

In this embodiment, the opening of the clutch valve 11 of the reverse clutch 9 is adjusted in consideration of the centrifugal clutch pressure P. That is, the CPU 42 calculates the above-described angular velocity ω based on the rotational speed signal input from the rotational speed sensor 17 via the input interface 45, reads out the angular velocity / centrifugal clutch pressure map from the ROM 43, and An estimated value of the centrifugal clutch pressure P corresponding to the detected rotation speed is calculated. The clutch valve 11 that controls the clutch pressure of the reverse clutch 9 that rotates integrally with the input shaft 3a is supplied with an oil pressure that is an engagement pressure less the centrifugal clutch pressure calculated as described above. Next, the opening of the clutch valve 11 is adjusted.

This embodiment has the following effects. (1) In the hydraulic clutch (reverse clutch 9) in which the clutch cover 9b rotates integrally with the input side, the centrifugal clutch pressure acting from the hydraulic oil in the pressure receiving chamber 9a is estimated based on the centrifugal force caused by the rotation of the input side. The set pressure of the electromagnetic control valve (reverse clutch valve 11) for setting the hydraulic clutch to a desired engagement pressure is set in consideration of the centrifugal clutch pressure. Therefore, the output of the hydraulic clutch that transmits the rotation of the input side that rotates at a high speed to the output side in a half-clutch state can be accurately controlled to a desired value.

(2) In an industrial vehicle in which drive wheels are driven via a transmission having a forward clutch and a reverse clutch, at least one of the forward clutch and the reverse clutch has a structure in which the clutch cover 9b rotates integrally with the input side. You are using a clutch. Therefore, the degree of freedom in arranging the clutch in the transmission is increased.

(3) At the time of loading operation, the vehicle speed is controlled by transmitting the rotation of the input shaft rotating at a high speed to the output shaft through a clutch adjusted to a predetermined engagement pressure in a half-clutch state. In this case, the opening of the clutch valve 11 for the reverse clutch 9 is adjusted in consideration of the effect of the centrifugal clutch pressure P. Accordingly, the desired clutch pressure can be accurately controlled, the target vehicle speed can be accurately controlled, and there is no risk that the industrial vehicle will continue to run at a very low speed even though it must be stopped.

(4) The rotation speed of the clutch cover 9b is obtained based on a detection signal of a rotation speed sensor 17 for detecting the rotation speed of the gear 16 provided integrally with the input shaft 3a, and the centrifugal clutch is obtained from the rotation speed. The pressure P is estimated.
Therefore, since there is a slip in the torque converter 2, even if the rotation speed of the output shaft 1a of the engine 1 does not strictly become the rotation speed of the input shaft 3a, the control accuracy of the hydraulic pressure supplied to the pressure receiving chamber 9a increases.

(5) The control of the hydraulic pressure supplied to the pressure receiving chamber 9a is not limited to the time of the cargo handling traveling, and also when the reverse clutch 9 is used as a braking clutch and the engagement pressure is adjusted in a half-clutch state during forward traveling. Accuracy is improved, and the braking action can be performed smoothly.

(6) The vehicle speed is controlled so as to correspond to the operation amount of the accelerator pedal 25 at the time of the cargo handling traveling, and the engine speed is controlled based on the operation amount of the cargo handling lever 33. When the work and traveling are performed simultaneously, the vehicle speed can be controlled only by operating the accelerator pedal 25, and the operation is facilitated.

The embodiment is not limited to the above, and may be embodied as follows, for example. When estimating the centrifugal clutch pressure P, the centrifugal clutch pressure P may be estimated from the engine speed without directly detecting the rotation speed of the input shaft 3a. Strictly speaking, the engine speed does not match the turbine speed, that is, the speed of the input shaft 3a, due to slippage in the torque converter 2. Therefore, the rotation speed of the clutch cover 9b does not become the engine rotation speed. However, when the clutch pressure during cargo handling is low,
Since the torque transmitted by the torque converter 2 is small and the slip between the pump impeller 2a and the turbine impeller 2b is also small, there is no problem even if the engine speed is substituted. Therefore, a map or a relational expression indicating the relationship between the engine speed and the centrifugal clutch pressure P is stored in the ROM 43,
Reference numeral 42 calculates the engine speed from the output signal of the engine speed sensor 15 when controlling the clutch pressure of the reverse clutch 9. Then, the centrifugal clutch pressure P is estimated from the map using the value, and the command value to the reverse clutch valve 11 is calculated as a value obtained by subtracting the centrifugal clutch pressure P from the clutch pressure required for the reverse clutch 9. In this case, the rotation speed sensor 17 for detecting the rotation speed of the input shaft 3a becomes unnecessary, and the configuration is simplified.

The centrifugal clutch pressure P is obtained from the engine speed.
When estimating, the weight of the load may be considered. The influence of the weight of the load is small because the clutch pressure is small during loading and running, but when the reverse clutch 9 is used as a brake during normal running, the clutch pressure may increase. In that case, the accuracy is improved in consideration of the weight of the load.

The clutch cover 9b of the reverse clutch 9
Is replaced with the input shaft and the integral clutch,
Or the clutch covers 8b and 9b of both clutches 8 and 9 may be integrally rotated.

Instead of transmitting the rotation of the engine 1 to the transmission 3 via the torque converter 2, the rotation may be transmitted directly to the transmission 3 without passing through the torque converter 2.

The clutch other than the clutch on the traveling side is engaged, the engagement pressure is adjusted, and the brake pedal 2
Instead of giving the braking force corresponding to the operation amount of 7, the function of the service brake may be given to the parking brake 12. For example, a proportional solenoid valve whose opening can be continuously adjusted is used as the brake valve 13. Then, a map or a relational expression indicating the relationship between the operation amount of the brake pedal 27 and the opening degree of the brake valve 13 for obtaining the braking force corresponding to the operation amount is stored in the ROM 43. The brake valve 13 is controlled to have a corresponding opening degree.

○ Both clutches 8, 9 and parking brake 1
Instead of incorporating a hydraulic pump for supplying hydraulic pressure to the second pressure receiving chambers 8a, 9a, and 12c in the transmission 3, a hydraulic pump 20 for supplying hydraulic oil to the lift cylinder 22 is used, and the respective pressure receiving chambers 8a, 9a, and 12c are used. It is good also as composition which supplies oil pressure to 12c.

The control device of the present invention is applied to a hydraulic clutch provided with a clutch cover that rotates integrally with the input shaft. However, the industrial vehicle provided with this control device is not limited to a forklift. Another industrial vehicle including a hydraulic device for cargo handling work, for example, a shovel loader may be used. In addition, the present invention is not limited to an industrial vehicle that always performs cargo handling in which cargo handling work and traveling work are performed at the same time. It may be applied to industrial vehicles.

The control device of the present invention is not limited to an industrial vehicle, and uses a hydraulic clutch having a clutch cover that rotates integrally with an input shaft to transmit the rotation of a drive source to a driven portion and to operate the clutch in a half-clutch state. The present invention can be applied to a device that changes the transmission force by adjusting the engagement pressure.

The inventions (technical ideas) other than those described in the claims that can be grasped from the above embodiments will be described below together with their effects. (1) In the invention described in claim 2 or 3,
The centrifugal clutch pressure estimating means estimates the centrifugal clutch pressure based on the rotation speed of the input shaft of the clutch. In this case, the centrifugal clutch pressure can be accurately estimated without being affected by the slip of the torque converter.

(2) In a hydraulic clutch in which a clutch cover constituting a pressure receiving chamber rotates integrally with the input side, the hydraulic pressure supplied to the pressure receiving chamber is controlled via an electromagnetic control valve. The centrifugal clutch pressure acting from the hydraulic oil in the pressure receiving chamber is estimated based on the accompanying centrifugal force, and the set pressure of the electromagnetic control valve for setting the hydraulic clutch to a desired engagement pressure is considered in consideration of the centrifugal clutch pressure. Hydraulic clutch control method to set. In this case, when the hydraulic clutch is used in a half-clutch state with the input-side rotational speed being large, and the engagement pressure of the clutch is adjusted to change the transmission force, the transmission force can be accurately changed.

[0062]

As described above in detail, according to the first to fourth aspects of the present invention, the influence of the centrifugal clutch pressure caused by the rotation of the hydraulic oil can be eliminated, so that the oil pressure in the pressure receiving chamber can be controlled with high accuracy. As a result, the clutch connection force can be suitably controlled.

According to the second to fourth aspects of the present invention, even when at least one of the hydraulic forward clutch and the reverse clutch provided in the transmission is rotated integrally with the input shaft, the vehicle speed can be accurately adjusted. Can control well.

According to the third aspect of the present invention, the control of the engagement pressure of the hydraulic clutch is performed in consideration of the effect of the centrifugal clutch pressure when the vehicle is running at a high engine speed and a low vehicle speed. Vehicle speed control can be performed, and it is possible to reliably prevent the vehicle from stopping even though the clutch should be disengaged.

According to the fourth aspect of the present invention, since the centrifugal clutch pressure is estimated based on the rotation speed of the engine provided with the rotation speed sensor, it is not necessary to provide a separate sensor, and the cost can be reduced. Become.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an industrial vehicle according to an embodiment.

FIG. 2 is a schematic partial sectional view of a reverse clutch.

FIG. 3 is a map showing a relationship between a centrifugal clutch pressure and an angular velocity.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Torque converter, 3 ... Transmission
3a: input shaft as input side, 5: drive wheel, 8: forward clutch as hydraulic clutch, 8a, 9a: pressure receiving chamber, 8
b, 9b: clutch cover, 9: reverse clutch as a hydraulic clutch, 10: forward clutch valve as an electromagnetic control valve, 11: similarly reverse clutch valve, 25: accelerator pedal as accelerator operating means, 33 ... as cargo handling operating means And a CPU as a centrifugal clutch pressure estimating means and a setting means.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F333 AA02 AB13 CA11 FA20 FA31 FD06 FE09 FH10 3J057 AA05 BB04 GA42 GA48 GA49 GA74 GB02 GB05 GB13 GB17 GB22 GB27 GB30 GB36 GB39 GE07 HH04 JJ01

Claims (4)

[Claims] 1. A control device for a hydraulic clutch, wherein a clutch cover forming a pressure receiving chamber rotates integrally with an input side, and a hydraulic pressure supplied to the pressure receiving chamber is controlled via an electromagnetic control valve. A centrifugal clutch pressure estimating means for estimating a centrifugal clutch pressure acting from the hydraulic oil in the pressure receiving chamber based on a centrifugal force associated with the rotation of the side, and an electromagnetic control valve for setting the hydraulic clutch to a desired engagement pressure. A control unit for setting the set pressure in consideration of the centrifugal clutch pressure. 2. The drive wheels are driven via a transmission having a hydraulic forward clutch and a reverse clutch for transmitting the output of the engine to the drive wheels via a torque converter. An industrial vehicle that uses a clutch other than a clutch as a braking clutch, wherein the hydraulic clutch according to claim 1 is used for at least one of the forward clutch and the reverse clutch, and the hydraulic clutch according to claim 1 is used for controlling the hydraulic clutch. An industrial vehicle provided with the control device as described in the above. 3. A hydraulic forward clutch and a reverse clutch which share one engine as a driving source for traveling and a driving source for cargo handling and transmit the output of the engine to driving wheels via a torque converter. In normal running, the traveling clutch is fully engaged and controlled to the target engine speed corresponding to the operation amount of the accelerator operation means. An industrial vehicle that controls the clutch engagement pressure so that a target vehicle speed corresponding to the operation amount of the accelerator operation means is controlled by controlling the target engine speed to the target engine speed and adjusting the forward clutch pressure. An industrial vehicle that uses the hydraulic clutch according to claim 1 for at least one side and includes the control device according to claim 1 for controlling the hydraulic clutch. 4. The industrial vehicle according to claim 2, wherein said centrifugal clutch pressure estimating means estimates said centrifugal clutch pressure based on an engine speed.