JP3383379B2 - Clutch operation mechanism for traveling vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic piston which is operated by supplying hydraulic oil to switch to a clutch-engaged state and release the supply of hydraulic oil to the hydraulic piston. Then, a multi-plate friction clutch in which the hydraulic piston retreats and switches to a clutch disengaged state by a return urging force of an urging mechanism, and a clutch operation amount for detecting a depression operation amount of a clutch pedal urged back to the clutch engagement position. Detecting means and a current supplied to the hydraulic piston
An electromagnetic proportional control valve which controls proportional to the value, so that the depression operation amount detected by the clutch operation amount detecting means becomes smaller value is large, the electromagnetic proportional control
The present invention relates to a clutch operating mechanism in a traveling vehicle provided with control means for controlling a current value for a valve . 2. Description of the Related Art In the above-mentioned clutch operating mechanism, conventionally, a control characteristic between an operating position of a clutch pedal and a current value for an electromagnetic proportional control valve is set in advance, and The depression amount of the clutch pedal is detected by a potentiometer as an example of the clutch operation amount detection means, the operation position of the clutch pedal is determined based on the detected value, and the current value corresponding to the operation position is supplied to the electromagnetic proportional control valve. The control characteristic is set as a characteristic that changes smoothly so that the current value decreases as the amount of depression of the clutch pedal increases. In other words, when the clutch pedal is not operated, the electromagnetic ratio
Example: The maximum current is supplied to the control valve , the operating pressure of the hydraulic piston is maximum, the clutch engagement state is reliably maintained, and the current value gradually decreases as the pedal is depressed, and the hydraulic operating force gradually decreases. The current supply is stopped shortly before the maximum depressed position, and the clutch disengaged state appears by the return urging force of the urging mechanism. However, in the above-mentioned conventional structure, the current value for the electromagnetic proportional control valve is determined with a constant change characteristic corresponding to the operating position of the clutch pedal. There was a problem. That is, when the clutch pedal is depressed from the non-operation position (a state in which the maximum hydraulic pressure is acting on the hydraulic piston), the supply current value to the electromagnetic proportional control valve gradually increases from the maximum value with the depression operation. The current value decreases. At this time, in the electromagnetic proportional control valve , the supplied spool moves the valve spool due to the supplied current, and the pressure oil gradually decreases. However, since the current value is determined by a constant change characteristic determined by the pedal operation position, if the clutch pedal is rapidly depressed from the non-operation position, a response delay of the valve spool occurs, and the clutch disengagement timing is affected by the pedal operation. And there was room for improvement. An object of the present invention is to eliminate the above disadvantages. A feature of the present invention is that in the clutch operating mechanism for a traveling vehicle described above, a shift position detecting means for detecting a shift position of a traveling transmission provided on a vehicle body is provided. The control means is configured to perform a non-operation of the clutch pedal when the clutch pedal is depressed from the clutch engagement position to the clutch disengagement position based on the detection result of the clutch operation amount detection means.
When in the working position, the maximum
Supply a current value to allow the hydraulic piston to
The multi-plate friction clutch is controlled so that the minimum hydraulic operating force required for power transmission is maintained until the set position is reached after it is detected that the clutch pedal has been operated. A control is performed so as to fix and maintain the set current value to be generated, and when the set position is reached, the current value is controlled based on a predetermined pedal operation amount and a current value change characteristic. The point is that the control is performed so as to change the set current value based on the detection result of the position detecting means. When the clutch pedal is depressed, for example, a setting in which the minimum hydraulic operating force required for power transmission is generated until the pedal reaches a set position near the end position of the idle operation range of the pedal where the power transmission does not change. Since it is fixedly maintained at the current value,
The valve spool of the proportional flow control valve moves from the maximum hydraulic pressure generation position to a position where the output oil pressure is lowered to the necessary minimum limit in advance, and waits in that state until the clutch pedal reaches the set position. Thus, in the operation from the non-operated state of the clutch pedal up to near the end of play manipulating area, since the electromagnetic proportional control valve will be waiting in the pressure drop condition, the solenoid proportional system regardless operating speed
The control valve is already in a standby state, and the response of the valve spool to a predetermined change characteristic in a subsequent depression operation is quickly performed. Further, the traveling load in accordance with the shift position of the travel gear device, i.e., because required transmission power is different, by a change in the shift position, by changing the set current value in the standby state as appropriate, the solenoid proportional
The control valve can always stand by at an appropriate set current value. Therefore, when the clutch pedal is depressed from the non-operation state, regardless of the difference in the pedal operation speed or the vehicle body shift position, the pedal operation after the clutch pedal has reached the set position is not affected. Electric
The follow-up response of the magnetic proportional control valve is improved, and the clutch disengagement timing corresponds to the pedal operation, thereby improving the operability. An embodiment will be described below with reference to the drawings. FIG.
1 shows a power transmission system in an agricultural tractor as a traveling vehicle. A transmission system is configured so that the power of the engine E is transmitted to the vehicle body traveling wheels W via the wet-type multi-plate friction type main clutch 1, main transmission H1 and auxiliary transmission H2. The operation mechanism of the main clutch 1 will be described. As shown in FIG. 2, the main clutch 1 has friction plates 3 and
When the hydraulic oil is supplied to the hydraulic piston 2 and the supply of the hydraulic oil to the hydraulic piston 2 is released, the hydraulic piston 2 is retracted by the return biasing force of the return spring 5 (an example of a biasing mechanism) and the clutch is switched to the clutch disconnected state. The clutch on / off operation is performed by depressing and releasing the clutch pedal 6. [0009] More specifically, the hydraulic control valve 7 for controlling the hydraulic pressure to oil chamber 2a of the hydraulic piston. 2 are configured to the electromagnetic proportional control valve for controlling the hydraulic pressure in proportion to a current value supplied, the electromagnetic The supply current value to the proportional control valve 7 is changed and controlled by a control device 8 (an example of a control means) equipped with a microcomputer based on the amount of depression of the clutch pedal 6. Clutch pedal 6
Is biased back to the clutch engagement position, and when depressed against the return biasing force, the amount of rotation of the pedal is adjusted by a potentiometer type pedal sensor 9 provided at a pivot point [an example of clutch operation amount detection means]. And the detected value of the pedal sensor 9 is given to the control device 8. Therefore, when the clutch pedal 6 is not operated, the clutch is in the engaged state, the hydraulic piston 2 is pressed by the pressure oil, and the power is transmitted. The hydraulic pressure is gradually released as the pedal is depressed, and the return spring 5 is released. As a result, the hydraulic piston 2 is returned, and the clutch is disengaged. [0010] Based on the detection result of the pedal sensor 9, the control device 8 controls the operation of the clutch pedal 6 from the clutch engaged position to the clutch disengaged position until the clutch pedal 6 reaches the set position. The main clutch 1 is controlled so as to be fixedly maintained at a set current value at which a minimum hydraulic operation force required for power transmission is generated. When the main clutch 1 reaches the set position, the current value is adjusted based on a predetermined pedal operation amount and a current value change characteristic. It is configured to control. Each of the main transmission H1 and the sub transmission H2 is provided with a shift position detection sensor S, S (an example of a shift position detecting means) for detecting a shift operation position. The configuration is such that the set current value is changed and controlled based on the detection results of the position detection sensors S, S. FIG. 4 shows a control procedure of the control device 8, and FIG.
Shows the current control characteristics. The output of each of the pedal sensor 9 and the shift position detection sensors S, S is read, and the minimum hydraulic operating force required for the main clutch 1 to transmit power is determined based on the shift position detection result and predetermined mechanical characteristics. The resulting current value Ia is set [steps 1 and 2]. When the clutch pedal 6 is in the non-operation position based on the detection information of the pedal sensor 9, the maximum current value Im is supplied to the electromagnetic proportional control valve 7 to keep the hydraulic piston 2 in the clutch-engaged state at the maximum hydraulic pressure. [Steps 3 and 4], and when it is detected that the clutch pedal 6 is slightly depressed from the non-operation position, the electromagnetic proportional control is immediately performed.
The set current value Ia is output to the control valve 7, and the current value Ia is maintained until the clutch pedal 6 is depressed to the set position Sa (Steps 5, 6). Thereafter, the clutch pedal 6 is further depressed to operate the set position S
When a exceeds a, as shown in FIG. 3, based on a predetermined pedal operation amount and a current value change characteristic, the current value is controlled so as to gradually and smoothly decrease as the depression amount increases. [Step 7]. At the maximum depression position, the output current value becomes zero, and the hydraulic piston 2 is operated by the return spring 5 to be in the clutch disengaged state. In the claims, reference numerals are provided to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control block diagram. FIG. 2 is a cross-sectional view of a main clutch. FIG. 3 is a control characteristic diagram of “pedal operation position-current (hydraulic operation force)” . Description: 1 Multi-plate friction clutch 2 Hydraulic piston 5 Biasing mechanism 6 Clutch pedal 7 Electromagnetic proportional control valve 8 Control means 9 Clutch operation amount detecting means H1, H2 Transmission S Shifting position detecting means

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-1-156147 (JP, A) JP-A-4-125319 (JP, A) JP-A-4-88214 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F16D 48/02 F16D 25/08

Claims (1)

(57) [Claim 1] When pressed by a hydraulic piston (2) operated by supplying hydraulic oil to switch to a clutch engaged state, and when the supply of hydraulic oil to the hydraulic piston (2) is released, A multi-plate friction clutch (1) in which the hydraulic piston (2) retreats and is switched to a clutch disengaged state by a return biasing force of a biasing mechanism (5); and a clutch pedal (6) biased back to a clutch engaged position. A) a clutch operation amount detecting means (9) for detecting a stepping operation amount, and a proportional flow control valve (7) for controlling a hydraulic oil amount to the hydraulic piston (2) to a flow rate proportional to a supplied current value.
Control means (8) for controlling a current value to said proportional flow control valve (7) such that the larger the stepping operation amount detected by said clutch operation amount detecting means (9), the smaller the value. A shift operation detecting means (S) for detecting shift positions of running transmissions (H1) and (H2) provided on a vehicle body, the control means ( 8) is based on the detection result of the clutch operation amount detection means (9), when the clutch pedal (6) is depressed from the clutch engagement position to the clutch disengagement position side by the clutch pedal (6)
When in the operating position, the electromagnetic proportional control valve (7)
To supply the maximum current value and the hydraulic piston (2)
Controlled to maintain clutch engagement at high oil pressure
Then, it is detected that the clutch pedal (6) is operated.
After that, until reaching the set position, the multi-plate friction clutch (1) is controlled so as to be fixedly maintained at a set current value at which a minimum hydraulic operating force required for power transmission is generated. The current value is controlled based on a determined pedal operation amount and a current value change characteristic. The control means (8) controls the set current value based on a detection result of the shift position detection means (S). A clutch operating mechanism in a traveling vehicle configured to control the clutch operation to be changed.