JPS622059A - Diagnostic device for trouble in continuously variable transmission - Google Patents

Abstract

PURPOSE:To discover a belt slip in an early period, by deciding a trouble through signals from speed sensors of a main pulley and a subpulley. CONSTITUTION:After an electromagnetic dust type clutch 1 comes to be directly coupled together with action of a switching clutch 22 in a pulley-type continuously variable transmission, a device, inputting signals of an engine speed and a car speed by sensors 50, 51 to a speed change ratio calculating part 54, calculates actual speed change ratio (i). While a rise up of line pressure is delayed in rapid acceleration, and if a belt slip is generated, the device generates an output H in a comparator 56 by increasing the speed change ratio (i), on the contrary the line pressure decreases in inertia running, and if the belt slip is generated, the device generates an output H in a comparator 58 by decreasing the speed change ratio (i). In this way, the device, inputting a signal of trouble decision to a counter 65 from an OR gate 64, turns on an alarm lamp 53 if the frequency of said signal increases.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a failure diagnosis device for a belt-type continuously variable transmission for a vehicle, and more particularly to a device that detects a slipping state of a belt, determines a failure before it becomes impossible to drive, and issues an alarm.

[Conventional technology]

This type of continuously variable transmission is known, for example, from Japanese Patent Application Laid-open No. 55-65755.
It is configured as shown in the publication. In other words, a drive belt is placed between the main pulley on the input side and the auxiliary pulley on the output side, and a hydraulic servo mechanism applied with line pressure automatically changes the speed by changing the pulley spacing. ing. In this case, the line pressure is high in low speed gears where the transmission torque is large to prevent belt slippage.
The pulley pressure is controlled to decrease as the speed increases, and the pulley pressure is always maintained in proportion to the transmitted torque. Therefore, in the above configuration, whether or not the belt slips is a very important factor. If belt slippage occurs, not only will gear change control become impossible, but power will no longer be transmitted to the output side, resulting in an inability to drive. Belt slippage can occur due to wear and tear on the pulleys and belt, oil leakage from the hydraulic system, etc., but if these problems have progressed and a malfunction has actually occurred, it would have been determined that the belt has failed. stomach. For this reason, it is necessary to monitor the slippage of the belt, determine a failure before the vehicle becomes unable to run, and issue a warning to prompt the user to carry out maintenance. However, failure diagnosis for the belt-type continuously variable transmission has not yet been performed. Fault diagnosis that is generally proposed for vehicles and the like mainly concerns electrical systems that operate under electrical control.

[Problems to be solved by the invention]

As is clear from the above-mentioned conventional examples, if a continuously variable transmission is not diagnosed for failure, when it is installed in a vehicle, it may become unable to run as described above. Here, we will discuss how to detect belt slippage, which is the basis for failure diagnosis. First, the actual gear ratio i is determined from the ratio of the engine rotation speed on the input side and the vehicle speed on the output side, or the ratio of the rotation speeds of both pulleys. This gear ratio 1 changes within the range of 0.5<i<2.5, for example, when there is no belt slippage. By the way, when shifting to a high gear at low speed, if you suddenly accelerate by pressing the accelerator and suddenly increase the engine speed and output, if the line pressure does not increase accordingly, belt slippage may occur. It happens that the vehicle speed does not increase. At this time, the gear ratio i is the lowest gear value 2.
The value will be greater than 5. Furthermore, if the line pressure is insufficient when coasting downhill with the accelerator released, the vehicle speed increases due to belt slippage, and the gear ratio i becomes a value smaller than the overdrive value of 0.5. In this way, belt slippage can be detected from the value of the gear ratio 1. On the other hand, the speed ratio change rate ldi/dtl is normally, for example, 0.2 to 0.3 per second, but if belt slippage occurs in a transient acceleration/deceleration range, a phenomenon that exceeds this value is observed. Therefore, belt slippage can be detected from the rate of change of the gear ratio i, thereby making it possible to diagnose belt slippage at an early stage. The present invention has been made in view of the above-mentioned problems, and it is possible to accurately perform a failure diagnosis regarding belt slippage in a continuously variable transmission at an early stage when the belt slippage is minute. The purpose is to provide diagnostic equipment.

[Means to solve the problem]

In order to achieve the above object, the present invention extends a drive belt around a main pulley and an auxiliary pulley with variable pulley spacing, supplies line pressure to a hydraulic servo device of each of these pulleys, and adjusts the winding of the pulleys at a ratio of their diameters. In a continuously variable transmission that continuously changes speed by changing the
The unit is configured to calculate the gear ratio, determine a failure from the value of the gear ratio and the value of the speed of change, and issue a warning based on the number of times the failure is determined.

[For production]

Based on the above configuration, the actual gear ratio is always detected while the transmission is operating, and if the gear ratio exceeds the maximum or minimum value or the change gear ratio exceeds the set value, a failure is determined and the frequency of occurrence is reduced. If the number increases, a warning will be issued to prompt the user to perform maintenance. In this way, it becomes possible to discover the actual state of failure related to belt slippage at an early stage and to deal with it.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, a continuously variable transmission with an electromagnetic powder clutch will be described as an example of a continuously variable transmission to which the present invention is applied in FIG. Continuously variable transmission 2 can be roughly divided into forward and reverse switching 8I.
I3, pulley ratio conversion section 4, final reduction section 5, and hydraulic control section 6
It consists of In the electromagnetic powder clutch 1, a drive member 9 with a built-in coil 8 is integrally connected to a crankshaft 1 from the engine, and a driven member 11 is integrally connected in the rotational direction by a spline to a transmission input shaft 10. The drive and driven member 9.11 is loosely fitted through the gap 12 in order to collect electromagnetic powder from the powder chamber 13 in this gap 12. Further, a slip ring 15 is installed on the drive member 9 via a holder 14, and a brush 16 for power supply is in sliding contact with the slip ring 15 so that a clutch current flows through the coil 8. In this way, when a clutch current is passed through the coil 8, electromagnetic particles are combined and accumulated in a chain in the gap 12 between the drive and driven members 9 and 11 due to the lines of magnetic force generated between the drive and driven members 9 and 11. On the other hand, the driven member 11 slides and becomes integrally connected. On the other hand, when the clutch current is cut, the drive due to the electromagnetic powder and the coupling force between the driven members 9 and 11 disappear, resulting in a clutch disengaged state. In this case, if the clutch current is supplied and cut in conjunction with the operation of the switching section 3 of the continuously variable transmission 2 using a shift lever, etc., it is possible to change the clutch current from P (parking) or neutral to N. When switching to (drive), L (low) or R (reverse) range, clutch 1 is automatically disengaged, making clutch pedal operation unnecessary. Next, in the continuously variable transmission 2, the switching AL13 is provided between the input shaft 10 from the clutch 1 and the main shaft 17 of the continuously variable transmission 112 disposed coaxially therewith,
A reverse drive gear 18 integrally coupled to the input shaft 10 and a reverse driven gear 19 rotatably fitted to the main shaft 17 are meshed with each other via a counter gear 20 and an idler gear 21, and furthermore, these main shaft 17 and gear 18 .19
A switching clutch 22 is provided between the two. Then, when the switching clutch 22 is engaged from the neutral position of the P or N range to the gear 18 side, the main shaft 17 is directly connected to the input shaft 10, and the switching clutch 22 is moved to the forward state of the D or H range.
When engaged on the 9 side, the power of the input shaft 10 is decelerated and reversed by the gears 18 to 21, resulting in a reverse drive state in the R range. In the pulley ratio converter 4, an nJ axis 23 is arranged parallel to the main shaft 17, and main pulleys 24. @Pulley 25 is provided, and pulley 24
, 25, an endless drive belt 26 runs between them. Both pulleys 24 and 25 are divided into two parts,
Hydraulic servo devices 27 and 28 are attached to the movable pulley halves 24a and 25a to make the pulley intervals variable. In this case, the main pulley 24 brings the movable pulley half 24a closer to the fixed pulley half 24b to gradually narrow the pulley interval, and conversely, the sub pulley 25 moves the movable pulley half 24a closer to the fixed pulley half 25b. By moving the movable pulley half 25a away from each other and gradually increasing the pulley interval, the drive belt 26
The winding around the pulleys 24 and 25 changes the diameter ratio so that continuously variable speed output power is extracted to the subshaft 23. In the final reduction section 5, a large-diameter final gear 32 meshes with an output gear 31 of an output shaft 30 connected to the subshaft 23 via an intermediate reduction gear 29, and a large-diameter final gear 32 meshes with an output gear 31 of an output shaft 30 connected to the subshaft 23 via an intermediate reduction gear 29. The power is transmitted to the axles 34 and 35 of the left and right drive wheels. Further, the hydraulic pressure 11Jtl11 section 6 is provided with a hydraulic pump 37 on the main pulley 24 side so as to constantly generate oil pressure during engine operation at a pump drive shaft 36 that passes through the main shaft 17 and the input shaft 10 and is directly connected to the engine crankshaft 7. is provided. This pump oil pressure is controlled by the oil pressure t, II 'a circuit 38 according to the throttle opening and engine rotation speed according to the depression of the accelerator, and is applied to the main pulley 24 and sub pulley 25 through oil passages 39 and 40. It is supplied to each hydraulic servo device [27, 28] and is configured to perform continuously variable speed control of the continuously variable transmission section 3. Referring to FIG. 2, failure diagnosis of the continuously variable transmission will be explained. Engine rotation sensor 50 detects engine rotation and vehicle speed. It has a vehicle speed sensor 51, and these engine rotation sensors 50. A vehicle speed sensor 51 is circuit-connected to a warning lamp 53 via a control unit 52 . The control unit 52 has a gear ratio calculating section 54 that calculates a gear ratio i based on the outputs of the engine rotation sensor 50 and the vehicle speed sensor 51, and this gear ratio calculating section 54 calculates the gear ratio i -2,5 of the lowest gear. A comparator 56 having a reference value 55 corresponding to
are connected to a comparator 58 having a reference value 57 corresponding to
Connect to. In addition, the gear ratio calculation unit 54 includes the gear ratio change-specific speed calculation unit 60 of the gear ratio calculation unit g l di / dt l.
．． Constant value 1di/dtl=1 via absolute value calculation unit 61
The OR gate 59 and the comparator 63 are connected to a comparator 63 having a reference value 62 corresponding to
It is connected via a gate 64 to a counter 65 for the number of failure determinations. The counter 65 is connected to a comparator 61 having a reference value 66, and the output of the comparator 67 lights up the alarm lamp 53. Note that the gear ratio cannot be calculated if the electromagnetic powder clutch 1 is disengaged or in a partially engaged state, or if the switching clutch 22 is in the neutral position. Therefore, after the clutch current of the electromagnetic powder clutch 1 flows and the clutch is directly connected after a certain period of time, and when the neutral switch is turned off, each sensor so, s is sent to the 1 control unit 52.
It is designed to take in the output of i. Next, the operation of the fault diagnosis device configured as described above will be explained. First, when you step on the accelerator while shifting to D or R range and operating the switching clutch 22 at the time of starting, the clutch current flows as the engine speed increases and the electromagnetic powder clutch 1 starts to connect, and the power is reduced. , switching section 3. Pulley ratio converter 4. It is transmitted to the wheels via the final reduction unit 5 and starts running. At this time, the drive belt 26 has moved furthest toward the auxiliary pulley 25 due to the action of the line pressure of the hydraulic servo device 2B, and the gear ratio i has become the maximum 2.5. In this way, when driving is started in the low gear with the maximum gear ratio, the electromagnetic powder clutch 1 is kept in the connected state due to the vehicle speed, and from this point on, line pressure is supplied to the hydraulic servo device 27 by pressing the accelerator and the vehicle speed. By shifting the drive belt 26 to the main pulley 24 side, the gear ratio is reduced and upshifted. Then, the gear ratio 1 reaches the minimum overdrive of 0.5. Therefore, in the above-mentioned continuously variable transmission, after the electromagnetic powder clutch 1 is directly connected with the operation of the switching clutch 22, the engine rotation speed and vehicle speed signals from each sensor so and si are input to the gear ratio calculation section 54. The actual gear ratio I is calculated. When the speed change control is performed normally, the outputs of the comparators 56, 58, and 63 all become L, and no failure determination signal is input to the counter 65, so no alarm is issued. On the other hand, if the line pressure rises late during sudden acceleration and belt slip occurs, the gear ratio i increases and the output of comparator 5G becomes H, and if the line pressure decreases during coasting and belt slip occurs, As the gear ratio i becomes smaller, the output of the comparator 58 becomes H. Further, when the speed ratio change rate 1 di/dt l increases due to belt slippage due to deterioration of followability of the line pressure during transient acceleration/deceleration, the output of the comparator 63 becomes H. In this way, a failure determination signal is input from the OR gate 64 to the counter 65, and when this number increases, the comparator 67 determines that there is a high possibility of a failure, and the output signal causes the alarm lamp 53 to light up. It gives a warning. Note that the above-mentioned action may be processed by software using a microcomputer or the like, and may be performed at predetermined intervals and at predetermined intervals in synchronization with the ignition pulse. Although one embodiment of the present invention has been described above, it can be applied to any continuously variable gear train transmission.

【Effect of the invention】

As described above, according to the present invention, belt slippage is detected based on the gear ratio and the speed of change of the gear ratio under driving conditions that are likely to cause belt slippage, such as sudden acceleration or coasting, so belt slippage can be detected at an early stage. can be reliably detected. Since the detection results are counted and a failure warning is issued, accurate failure diagnosis can be performed before the vehicle becomes unable to run. Further, it is also possible to perform a check in advance by reading the contents of the failure diagnosis device at a vehicle inspection or the like.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing an example of a continuously variable transmission to which the present invention is applied, and FIG. 2 is a circuit diagram showing an embodiment of the failure diagnosis device of the present invention. 2...Continuously variable transmission, 4...Pulley ratio conversion section, 24.
... Main pulley, 25 - Sub-pulley, 26 - Drive belt, 27.28 - Hydraulic servo device, 50 - Engine rotation sensor 51 - Vehicle speed sensor, 52 - Control unit, 53... Alarm lamp, 54... Gear ratio calculation unit, 60... Gear ratio change speed calculation unit.

Claims (1)

[Claims] A drive belt is applied to the main pulley and sub pulley with variable pulley spacing, line pressure is supplied to the hydraulic servo device of each pulley, and the ratio of the winding diameters of the pulleys is changed. A continuously variable transmission that changes speed has a rotation sensor that detects the rotation speed of a main pulley side and a sub pulley side, and a control unit calculates a gear ratio based on a signal from the rotation sensor, and calculates at least the value of the gear ratio, A failure diagnosis device for a continuously variable transmission that determines a failure based on any value of the rate of change and issues an alarm based on the number of times the failure is determined.