JPH0411864Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Technical Field of the Invention) The present invention relates to a differential control device, and more specifically, a device for controlling the differential of a differential device in a vehicle equipped with a transmission and a differential device having a differential limiting mechanism. Regarding. (Prior art) In addition to a normal differential mechanism, a differential device capable of limiting differential motion includes a differential limiting mechanism consisting of a plurality of friction plates and a hydraulic device for operating these friction plates. The differential that occurs is limited by bringing the friction plates into contact. As a result, the differential is limited when the running speed exceeds a predetermined value to improve running stability (for example, Japanese Patent Application Laid-Open No. 60-237242), or the differential is limited depending on the size of the turning angle. It is possible to cancel this function and achieve both turning performance and driving performance. (Problem that the invention aims to solve) When the vehicle speed exceeds a predetermined value even though it is necessary to ensure sufficient tire traction when starting the vehicle, driving uphill, towing, etc. If the differential is limited to , it is not possible to obtain the necessary traction. An object of the present invention is to provide a differential control device that controls a differential limiting mechanism to ensure traction when starting, running uphill, towing, etc. (Means for Solving the Problems) The present invention is a device for controlling the differential of a differential in a vehicle equipped with a transmission and a differential having a differential limiting mechanism. A sensor that detects the shift position of the transmission, a sensor that detects the engine speed,
a controller that obtains torque based on signals from both of the sensors; and a controller that operates the differential limiting mechanism to limit the differential under the control of the signals from the controller when the torque exceeds a predetermined value. and means to do so. (Functions and Effects) For example, the controller has previously stored in a map the correlation between the engine speed and the propeller shaft torque for each shift position.
When signals from the shift position sensor and engine speed sensor are input to the controller, the controller selects a map corresponding to the shift position and obtains propeller shaft torque from the map based on the engine speed. When the torque exceeds a predetermined value, the controller operates the operating means to limit the differential. This limits the differential movement between the left and right tires, making it possible to apply large torque to the tires. When starting, driving uphill, towing, etc., the torque of the propeller shaft is increased and the traction of the tires is increased, so the vehicle runs smoothly.
However, when driving at low speeds, the torque is reduced and the left and right tires are differentially driven, so turning performance is not impaired. The controller does not directly detect the propeller shaft torque, but indirectly obtains the propeller shaft torque from the shift position and engine speed, and controls the differential based on this torque. It can be manufactured at low cost. (Example) As shown in FIGS. 1 and 3, the differential control device 10 includes a differential device 1 having a differential limiting mechanism 12.
4, a sensor 16 that detects the shift position of a transmission (not shown), a sensor 18 such as a tachometer that detects the engine speed, and a controller 20.
and an operating means 22. Any differential device can be used as long as it has a differential limiting mechanism. The differential device 14 shown in FIG. 3 includes a differential case 24, a plurality of pinions 26 disposed inside the differential case 24, and a pair of side gears 2.
8 (one is shown in the figure) and a shaft 30 connected to each side gear 28. The differential limiting mechanism 12 limits the differential movement of the differential device 14 and engages a plurality of first friction plates 32 that engage one side gear 28 and the differential case 24. A plurality of second friction plates 34 are provided. A first differential carrier 36 is fixedly disposed surrounding the differential case 24 and rotatably supports the differential case 24. A second differential carrier 38 is secured to the first differential carrier 36. A cylindrical spacer 40 is attached to the shaft 30, and a first friction plate 32 is supported by the spacer 40 so as to be non-rotatable and movable in the axial direction of the shaft 30. On the other hand, a transmission member 42 non-rotationally coupled to the differential case 24 is disposed surrounding the shaft 30. Transmission member 4
2 has an enlarged diameter at a portion beyond the first differential carrier 36, and a second friction plate 34 is supported in this enlarged diameter portion so as to be non-rotatable and movable in the axial direction. The first friction plates 32 and the second friction plates 34 are arranged alternately. A second differential carrier 38 surrounds the enlarged diameter portion of the transmission member 42. A piston chamber 44 is provided in the second differential carrier 38, and a first piston 46 is movably and non-rotatably arranged in the piston chamber 44. The second piston 48 is the first piston 4
6, and this second piston 48 is supported by the spacer 40 so as to be non-rotatable and movable in the axial direction. A thrust bearing 50 connects the first piston 46 and the second piston 4
8. When hydraulic pressure is introduced into the piston chamber 44 from the outside,
The first piston 46 is pressed against the second piston 48 via the thrust bearing 50, and the first
A friction force proportional to the pressing force is generated between the friction plate 32 and the second friction plate 34. This frictional force limits the differential movement of the differential device 14. At this time, the reaction force generated in the transmission member 42 is transmitted to the thrust washer 52 disposed between the differential carriers 36 and 38, the thrust washer 54 disposed on the transmission member 42, and the thrust bearing 56 disposed between the two washers. and is caught by the differential carrier 36. In the case of manual operation, as shown in FIG. 4, the shift position detection sensor 16 detects a switch 63 corresponding to the shift position occupied by the shift lever 60 during 1st to 5th gears and reverse.
It is composed of a detection plate 62 on which elements a, 63b, . . . , 63f are arranged. Each switch consists of a limit switch, a proximity switch, and other switches, and when the shift lever 60 shifts, the switch at the corresponding shift position is turned on. In the case of automatic check operation, the shift position detection sensor 16 is constituted by a solenoid valve and a neutral start switch 64 shown in FIG. i.e. multiple solenoid valves
Where S ₁ , S ₂ , S ₃ are used to move the gears of the transmission, the relationship between their operating state and the shift position of the gears is as shown in the table below (in this example is for an electronically controlled automatic transmission).

[Table] On the other hand, the neutral start switch 64 consists of a printed wiring board 65a and a switching lever 65b, and depending on the position of the switching lever 65b, parking P, reverse R, neutral N, forward movement D, etc. are detected. Therefore, the shift position can be determined by a combination of the solenoid valve signal and the neutral start switch 64 signal. The controller 20 is a CPU or a computer, and includes a map 66 that stores the correlation between the engine speed and the propeller shaft torque for each shift position, as shown in FIG. 2. , listed on one map). Therefore, when a signal from the shift position sensor 16 is input to the controller 20, the map corresponding to that shift position is selected, and
Thereafter, the torque of the propeller shaft is obtained based on the engine speed from the engine speed sensor 18 (68). When the obtained torque exceeds a predetermined value, the operating means 22, which will be described later, is operated to limit the differential movement of the differential limiting mechanism 12. Here, the predetermined value of torque is set to be greater than or equal to zero. In the illustrated embodiment, the operating means 22 includes a liquid pump 70, an unload relief valve 72, an accumulator 74, a current-controlled pressure reducing valve 76, and a check valve 78. A tube 80 connects the pump 70 and the second differential limiting mechanism 12.
The pipe 80 communicates with the piston chamber 44. An unload relief valve 72 is installed in the pipe 80 , and a current-controlled pressure reducing valve 76 is installed in a portion leading from the unload relief valve 72 to the differential limiting mechanism 12 . Further, an accumulator 74 is connected between the unload relief valve 72 and the current-controlled pressure reducing valve 76,
A check valve 78 is installed between the unload relief valve 72 and the accumulator 74. Check valve 78 only allows liquid flow or pressure transmission from unload relief valve 72 toward accumulator 74 . When pressurized liquid is supplied from the pump 70, the unload seat of the unload relief valve 72 is closed and the check valve 78 is opened. As a result, pump 70
The pressurized liquid from is led to the accumulator 74 via the pipe 80, where the liquid pressure is increased. When the pressure of the accumulator 74 reaches the adjustment pressure of the unload relief valve 72, the unload relief valve 72 instantly opens, the pressurized liquid from the pump 70 returns to the reservoir tank 82, and the check valve 78 closes. Thus,
A constant pressure is stored in the accumulator 74. The current-controlled pressure reducing valve 76 has a DC solenoid installed in its pilot section, and controls the pressure continuously and steplessly by controlling the input current to the solenoid. The control pressure in this case is then substantially proportional to the input current. Therefore, if the current applied to the current-controlled pressure reducing valve 76 is controlled by the controller 20, an appropriate pressure can be obtained. In the case of the embodiment, since the current-controlled pressure reducing valve 76 supplies pressure proportional to the current to the differential limiting mechanism 12, the differential can be limited continuously according to the magnitude of the torque of the propeller shaft. . To do this, the controller 20 must have a torque T and a liquid chamber 4.
4 and the relationship between pressure P and current i are stored as a map (69), and this relationship is used to limit the differential. That is, the controller 20 determines the pressure P corresponding to the torque T from the map, and supplies the current i to the current control pressure reducing valve 76 to obtain this pressure P. Then, the pressure P is supplied to the differential limiting mechanism 12, and the first piston 46 presses the second piston 48 with a force proportional to the pressure. As a result, the first and second friction plates 32 and 34 come into contact with each other, a friction force proportional to the pressure is generated, and the differential movement of the differential mechanism 12 is limited. When a directional control valve or a switching valve is provided in place of the current-controlled pressure reducing valve 76, the obtained torque is compared with a predetermined value, and when the obtained torque exceeds the predetermined value, the differential is limited. However, when the value is less than a predetermined value, the differential restriction is canceled.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the differential control device, Fig. 2 is a control flowchart, Fig. 3 is a sectional view of the differential device, and Figs. 4 and 5 are plan views of the sensor that detects the shift position. It is. DESCRIPTION OF SYMBOLS 10... Differential control device, 12... Differential limiting mechanism, 14... Differential device, 16... Shift position detection sensor, 18... Engine rotation speed detection sensor, 20... Controller, 22... Operation means,
60...Shift lever, 62...Detection plate,
64...Neutral start switch, 76...
...Current-controlled pressure reducing valve.

Claims (1)

[Scope of utility model registration request] A device for controlling the differential of the differential in a vehicle including a transmission and a differential having a differential limiting mechanism, the sensor detecting a shift position of the transmission;
A sensor that detects engine rotation speed, a controller that obtains torque based on signals from both of the sensors, and when the torque exceeds a predetermined value, the differential is controlled by the signal from the controller and limits the differential. and means for operating the differential limiting mechanism.