JPH01120461A - Hydraulic pressure drop diagnostic device for transmission clutch - Google Patents

Abstract

PURPOSE:To detect points in a clutch where hydraulic pressure is dropped and to avoid use of defective clutch by checking signals to for a hydraulic sensor, a reverse switch, an N switch and a solenoid valve according to a ROM program. CONSTITUTION:A controller 11 detects hydraulic pressure drop of a clutch based on a signal fed from a hydraulic sensor 4, engaging drive clutch 16 or reverse clutch 17 based on a signal fed from a neutral switch 10 and engaging 1-speed or 2, 3-speed clutches 18-20 based on signals to be fed to solenoid valves 5, 6 according to a program written previously into an inner ROM. Then shifting operation of F/N/R lever 7 is disabled based on a signal fed to an air cylinder 37 to realize speed change and neutral of a transmission forcibly through the solenoid valves 5, 6 and to diagnose a clutch having dropped hydraulic pressure through combination with detecting operation and the like, thereafter usage of defective clutch is prohibited by means of the solenoid clutches 5, 6. Consequently, burning, abrasion, of clutch board temperature rise and degradation of transmission oil can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a transmission for an industrial vehicle such as a forklift.

[Conventional technology]

Conventional power shift transmissions are manual and do not include means for detecting oil pressure drop.

[Problem that the invention seeks to solve]

(1) Conventional power shift transmissions were not equipped with means for detecting a drop in oil pressure, and therefore could not detect a drop in clutch oil pressure due to oil leakage caused by damage to a clutch piston seal or the like.

(2) Even if it is equipped with an oil pressure drop detection means.

If the transmission is a manual type, the tasks of ■avoiding the use of a clutch with low oil pressure, and ■searching for the location of a clutch with low oil pressure depend on manual operations, making it difficult to carry out secondary work. It was difficult.

(3) As a result, the clutch with low oil pressure will continue to slip even after the failure, resulting in: Seizing and abrasion of the clutch plate, resulting in an increase in transmission oil temperature, and Contamination and deterioration of the transmission oil. This caused problems such as this, and expanded the range of failures.

[Means for solving problems]

As shown in FIG. 1, (1) A hydraulic pressure sensor 4 (a hydraulic pressure switch may be used) is installed in the control valve 2 on the downstream side of the accumulator valve 3, and a hydraulic pressure drop signal is sent to the controller 11.

(2) The speed change of the transmission 1 is automated by the solenoid valves 5 and 6 operated by a signal from the controller 11.

(31 A reverse switch 9 and a neutral switch 10 are installed on the spool 8a of the F (forward)/N (neutral)/R (reverse) switching valve 8, and the position of the F/N/R lever 7 is sent to the controller 11.

(4) Air cylinder 37 and shift inhibit lever 38 driven by signals from controller 11
Press K to restrict the movement of the F/N/R lever.

[Effect]

The controller 11 controls the input/output of the above signals according to a program written in advance in the internal ROM,
The following effects are realized.

(1) A drop in clutch oil pressure is detected by a signal from the oil pressure sensor 4.

(2) The engaged directional clutch is detected by the signals from the reverse switch 9 and the neutral switch 10.

(The gear clutch being engaged is detected by signals to the 3111 magnetic valves 5 and 6.

(4) F/N by signal to air cylinder 37
/R lever 7 glue 7 is prohibited.

(5) Transmission 1 is forced by signals to solenoid valves 5 and 6.
Achieve speed change and neutralization, and search for clutch locations with low oil pressure in combination with the effects of (1) to (4).

(6) After diagnosing the low oil pressure clutch location, the same (solenoid valve 5.
6 avoids the use of a failed clutch.

(Example) In Figs. 1 to 5, 1 is a transmission, 2 is a control valve, 3 is an accumulator valve, 4 is an oil pressure sensor, 5 and 6 are electromagnetic valves, and 7 is a forward (F)/neutral (N) )/reverse direction switching lever, 8 is F/N
/R switching valve, 8a is spool, 9 is reverse switch,
10 is a neutral switch, 11 is a controller, 1
2 is an engine, 13 is a bevel gear, 14 is a final reduction gear, 15 is a tire, 16 is a forward clutch,
17 is a reverse clutch, 18 is a 1st speed clutch, 19 is a 2nd speed clutch, 20 is a 3rd speed clutch, 21 is a torque controller ζ
22 is a hydraulic pump, 23 is a transmission oil pan, 2
4 is a suction strainer, 25 is a line filter, 2
6 is the main regulator valve.

27 is a reducing valve, 28, 29 is a speed shift valve, 30 is an orifice, 31 is a differential valve, 32 is an inching valve, 33 is an inching pedal, 34 is a transmission output shaft gear 35 is a vehicle speed sensor ,3
6 is a lamp, 37 is an air cylinder, and 38 is a shift inhibit lever.

The functions of the control system diagram in FIG. 1 will be explained.

(1) The transmission 1 is a planetary power shift transmission with a three-speed forward and reverse torque converter.

(2) The output from the engine 12 is transmitted to the tires 15 through the bevel gear 13 and the final reduction gear 14 after the speed stage is determined by the transmission l.

(3) The transmission 1 determines the direction by engaging either the forward clutch 16 or the reverse clutch 17 of the direction clutches, and the gear clutches 1st gear clutch 18, 2nd gear clutch 19, and 3rd gear clutch 20. It is a two-pack control that determines the speed stage depending on which one is engaged.

(4) That is, 1. For example, by engaging the forward clutch 16 and the 1st speed clutch 18, the forward fi 1 speed can be achieved, and by engaging the reverse clutch 17 and the 3rd speed clutch 20, the forward fi 1 speed can be achieved.

(5) The neutral of the transmission 1 is ■Forward clutch 16
and reverse clutch 17.

■This can be achieved by releasing all of the 1st speed clutch 18, 2nd speed clutch 19, and 3rd speed clutch 20. In other words, even if one of the speed clutches is engaged, by releasing the directional clutch, one of the directional clutches will be released.
Is it the speed gear clutch even if it is engaged? By releasing it, the transmission 1 can interrupt power transmission and achieve neutral.

(6) Control valve 2 controls the speed change (4dl).

(7) The hydraulic pump 22, which is attached to the impeller of the torque converter 21 in the transmission 1 and rotates at the same time as the input R, sucks up oil from the transmission oil pan 23 through the suction strainer 24, and passes it through the line filter 25 to the control valve 2. Guide (.

(8) The pressure of the oil is regulated to the main clutch pressure by the main regulator valve 26, and the relieved oil is guided to the torque converter 21.

(9) v! The oil under four pressures is divided and guided to the reducing valve 27 and the accumulator valve 3.

The αQ reducing valve 27 reduces the main clutch oil pressure and sets the pilot oil pressure for shifting the speed gear shift valves 28 and 29.

(Ll) Normally, the accumulator valve 3 accumulates oil, and when the clutch is engaged, it has two functions: ■ Filling the accumulated oil into the clutch chamber to be engaged, and ■ The orifice 30 when the clutch is engaged. Temporarily increase the oil pressure (apply modulation) to alleviate the shock when shifting 1
Responsible for cooking.

The clutch hydraulic pressure is divided downstream of the accumulator valve 3, one being guided to the speed shift valve 28, 29, and the other being led to the F/N/R switching valve 8 via the differential valve 31 and inching valve 32. be guided.

(13 The differential valve 31 provides a differential pressure between the gear clutch pressure and the directional clutch pressure. Normally, the directional clutch pressure is set low, and the directional clutch absorbs energy during gear shifting.

I The inching pedal 32 is the inching pedal 33.
The directional clutch pressure is reduced depending on the amount of pedal depression, realizing half-clutching and disengaging the clutch.

(15F/N/R switching j loop 84!F/N/Rv
Manually operated by the half, distribution of directional clutch pressure to forward clutch 16 and reverse clutch 17.

Alternatively, switching between F/N/R is realized by releasing both clutch pressures. F/N/R switching] The spool 8a of the lube 8 is equipped with a reverse switch 9 and a neutral switch 10, which are turned on and off by the movement of the spool.The signal from one switch is sent to the controller II, and the controller 11 switches to the F/N/R switch. /N/R The position of lever 7 is being detected. The relationship between the switch signal and the lever position is as shown in FIG. The air cylinder 37 driven by a signal from the controller 11 moves the shift inhibit lever 38 up and down, thereby inhibiting and canceling shifting of the F/N/R lever 7.

αe Speed stage shift valves 28 and 29 are each solenoid valve 5.
60 is shifted by opening and closing, and by the combination of one and two shift valves, the speed clutch hydraulic pressure is distributed to the 1st to 3rd gears, the latch, or the all speed clutches are released, and the shift between 1st to 3rd gears and neutral. is responsible for the realization of

The combination of the speed shift valves 28 and 29 is the solenoid valve 5.
, 6 are replaced with ON and OFF, and the relationship with each speed stage is shown in FIG. The electromagnetic valves 5 and 6 are driven by electrical signals from a controller 11. A vehicle speed sensor 35 is installed on the output shaft gear 34 of the transmission 1 and sends a vehicle speed signal to the controller 211. The controller 11 follows a preset program,
Normally, automatic gear shifting is achieved by sending signals to valves 5 and 6 according to the vehicle speed. As described above, the controller 11 also determines the speed stage based on the signal, so the controller 11 always recognizes the current speed stage.

As mentioned above, the F/N/R switching valve 8 and the speed shift valves 28 and 29 can each achieve neutral, but both valves can achieve neutral.

When each is in the neutral position, all the direction clutches or all the speed clutches of the transmission 1 are released (draining the hydraulic pressure in the clutches), and at the same time, the flow of the main clutch hydraulic pressure to the clutch chamber is continuously interrupted. do. As a result, the main clutch oil pressure does not decrease when in neutral, and the pressure set by the main regulator valve 26? Hold.

0F! J A hydraulic sensor 4 installed downstream of the accumulator valve 3 detects the main clutch hydraulic pressure.

It is sent to the controller 11. When there is no leakage in the clutch and the direction clutch and speed clutch are engaged normally, and when the clutch is in neutral, the main clutch oil pressure is at a normal level.

When the main clutch oil pressure decreases due to leakage of clutch oil pressure due to damage to the clutch piston seal, failure of the hydraulic pump 22, etc., the oil pressure sensor 4 detects this and notifies the controller 11 of the occurrence of the failure. However, when switching F/N/R or changing gears, the main clutch oil pressure flows into the clutch chamber, which had been released and drained of oil.
Thereafter, the main clutch oil pressure decreases while the clutch oil pressure increases temporarily due to the modulation gamma function of the accumulator valve 3, so this signal must be ignored.

Therefore, if the oil pressure decreases continuously for longer than the oil pressure decrease time during normal gear shifting, it is considered to be abnormal. Diagnosis can be made by looking at changes over time like this.

Ignoring pulsed noise signals also increases the reliability of the system.

Appointment! The lamp 36 blinks in response to a signal from the controller 11, and displays the diagnostic result of the oil pressure drop.

The oil pressure drop diagnosis logic (programmed in the ROM in the controller 11) using this system is shown in FIG.

- This logic is started when the oil pressure sensor 4 detects a continuous decrease in main clutch oil pressure for a period longer than the shift time (39 in the figure).

C1j First, the currently engaged speed clutch (to which a signal is sent from the controller) is stored (40 in the figure).

(22) Next, send a signal to the air cylinder 37 to F/N
/R Prohibits the lever 7 from shifting (41 in the figure).

This is to prevent F/N/R switching from occurring during diagnosis of a low clutch oil pressure location, which would make it impossible to detect a failure location.

Next, signal to *magnetic valves 5 and 6! Forcibly set the gear clutch side to neutral (42 in the figure). This means first diagnosing the failure from the directional clutch side.

(24+ Next, check whether the oil pressure is still decreasing (43 in the diagram).

(c) If it continues, then the position of the F/N/R lever 7 is detected by the signals from the reverse switch 9 and the neutral switch 10 (44 in Figure 1). This makes the controller.

The location of a faulty clutch can be detected. Next, the flashing of the failure display lamp 36 is changed depending on the position, and the failure clutch position is displayed (45.46°47 in the figure). If the position is N, it is determined that the problem is not a clutch failure but an oil source abnormality such as a leak in a pipe or a hydraulic pump failure. When the position is F or R, it is displayed that the F or R clutch has failed, but strictly speaking, this system cannot distinguish whether the problem is with the clutch or the oil source. However, based on the past experience with this system, clutch failures such as clutch piston seal damage are the most common cause of low clutch oil pressure. We do not make this distinction because we are assuming a diagnostic system. After the faulty clutch position is displayed, in any case, wait until the vehicle speed reaches 0/12/h (43 in the diagram).
, the shift inhibit of the F/N/R lever is released (49 in the figure), the speed is forcibly set to 1st gear (50 in the figure), and F/N/R driving in only 1st gear is possible thereafter (49 in the figure). 51)
. This is to enable emergency evacuation of the vehicle after a breakdown.The reason why the first speed is fixed is that the reduction ratio of transmission 1 is increased (i.e., the clutch oil pressure decreases and the clutch slips). This is to reduce the load on the directional clutch as much as possible.

(a) In the above CJ4), if the oil pressure drop is recovered in step 43, it is determined that the cause of the oil pressure drop is a failure of the gear clutch. Therefore, the speed clutch stored in step 40 is called (52 in the figure).

If the speed clutch is in 1st gear, the 1st gear clutch oil pressure drop is indicated by the lamp 36 (53 in the figure), and after waiting for the vehicle speed to reach O/z/h (56 in the figure), 57) in the figure to release the shift inhibit, force the speed stage to 2nd gear (58) in the figure, and then F/N/R in 2nd gear only.
It is possible to run (59 in the figure). This is to avoid the use of a failed first gear clutch and to enable emergency evacuation of the vehicle after a failure. At step 52, the speed clutch is set to 2.
If the vehicle is in 3rd or 3rd gear, the oil pressure reducing clutch will be displayed on the lamp 36 (Figure 54.55), and the vehicle speed will be 0.
After waiting for the ICIR/h to reach ICIR/h (60 in the figure), shift inhibition can be canceled (61 in the figure). Both are forced into 1st gear (62 in the figure), and thereafter F/N/R in 1st gear.
It is possible to run (63 in the figure).

This is also to avoid the use of a failed clutch and to enable emergency evacuation of the vehicle after a failure.

FIG. 5 shows the relationship between the above failure lamp display and failure details.

〔Effect of the invention〕

(1) It is possible to detect a drop in the clutch oil pressure of the nower shift transmission.

(2) A single oil pressure sensor can automatically locate a failed clutch.

(3) The use of a failed clutch can be automatically avoided.

(4) This prevents the clutch from being used for a long time in a slipped state when the clutch oil pressure has decreased, causing seizure and wear of the clutch plate, ■ rise in transmission oil temperature due to the above (■), and ■ gear shifting. It is possible to prevent the spread of malfunctions such as contamination and deterioration of machine oil.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram of an embodiment of a transmission incorporating the transmission clutch oil pressure drop diagnosis device of the present invention. Figure 2 shows the reverse switch and neutral switch signals in Figure 1 and the F/N/R lever d? FIG. FIG. 3 is a diagram showing the relationship between ON/OFF of the solenoid valve in FIG. 1 and the speed stage. FIG. 4 is a flowchart of clutch oil pressure drop diagnosis logic according to the present invention. FIG. 5 is a diagram showing the relationship between the display of the failure lamp in FIG. 1 and the details of the failure. 1...Transmission, 2 e-control valve. 3...Accumulator valve. 4... Oil pressure sensor, 5, 6... Solenoid valve. 7...Forward (F)/neutral (N)/reverse switching lever. Death...F/N/R switching valve. 8a...Spool 9...Reverse switch. 10...Neutral switch. 11... Controller, 37... Air cylinder. 38...Futinhibit lever

Claims (1)

[Claims] A hydraulic sensor installed downstream of an accumulator valve built into a control valve of a transmission, a solenoid valve that controls gear shifts of the transmission by turning on and off an electric signal, and F/N/ The reverse switch and neutral switch are attached to the spool of the F/N/R switching valve, which is switched by the R lever, and the air cylinder is driven by a signal from the controller.
A transmission clutch oil pressure drop diagnostic device comprising: a shift inhibit lever that inhibits movement of the R lever; and a controller that inputs and outputs signals from the sensor and actuator according to a preset program.