JPH0434269Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a differential control device, and more particularly, the present invention relates to a differential control device, and more particularly, the present invention relates to a differential control device in a vehicle equipped with an automatic transmission and a differential device having a differential limiting mechanism. The present invention relates to a device for controlling the differential of a motor.

(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 generated differential is limited by bringing friction plates into contact (for example, Japanese Patent Laid-Open No. 190147/1983). As a result, the differential is limited when the running speed exceeds a predetermined value to improve running safety (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 driving uphill or towing, it is necessary to ensure sufficient tire traction, but it is necessary to limit the differential when the vehicle speed exceeds a predetermined value. If you do so, you won't be able to get the traction you need.

Separately proposed differential limiting mechanism (1986-
No. 162942) is 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, which includes a sensor for 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 a controller that controls the differential when the torque exceeds a predetermined value. and means for operating the differential limiting mechanism.

According to the differential control device according to this proposal, the necessary traction can be obtained when traveling uphill or when towing the vehicle, but the control is relatively complicated.

An object of the present invention is to provide a differential control device that can ensure necessary traction through simple control when a vehicle equipped with an automatic transmission travels uphill or when towing the vehicle.

(Means for Solving the Problems) The present invention is a device for controlling the differential of a differential in a vehicle equipped with an automatic transmission and a differential having a differential limiting mechanism. a sensor for detecting a kick-down state of the transmission; a controller for receiving a signal from the sensor; and an operating means controlled by the controller, the differential limiting means being configured to limit the differential when the transmission is kick-down. and means for operating the mechanism.

(Functions and Effects) When the automatic transmission kicks down, that is, when the vehicle is running in a high gear and the accelerator pedal is depressed beyond a predetermined opening, the gear is automatically shifted to a lower gear. , a signal is sent from the sensor to the controller. Upon receiving this signal, the controller determines whether or not kickdown is occurring, and when kickdown is occurring, 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.

The traction of the tires is increased when driving uphill, when towing, etc., so the vehicle runs smoothly, but in this case control is performed only based on whether or not the vehicle is in a downhill state, so control is simple. be.

(Example) As shown in FIGS. 1 and 3, the differential control device 10 includes a differential device 1 having a differential limiting mechanism 12.
A sensor 1 that controls the differential of the automatic transmission (not shown) and detects a kickdown of the automatic transmission (not shown)
6, a controller 18, and an operating means 20.

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 shown in each figure) and a shaft 30 connected to the 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. It is caught by differential archia 36.

The sensor 16 that detects kickdown sends a signal used for determining the shift point directly to the controller 18.
It can be configured by a circuit that reads In other words, in automatic transmissions, the control system usually
It determines the shift point, which is the position at which the gear ratio of the transmission is automatically switched, and outputs a signal to a solenoid or the like. Therefore, by guiding this signal to a controller, which will be described later, it is possible to detect a kickdown.

The controller 18 is a CPU or a computer, and determines whether or not the automatic transmission is kicking down, and when the automatic transmission is kicking down, limits the differential movement of the differential limiting mechanism 12 via an operating means to be described later. .

In the illustrated embodiment, the operating means 20 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 through the pipe 80, where the liquid pressure is increased. When the pressure of the accumulator 74 reaches the adjusted pressure of the unload relief valve 72, the unload relief valve 72 instantly opens, the pressurized liquid from the pump 70 flows back 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 this 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 18, 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 continuously limited. Therefore, the controller 18 performs the control shown in FIG.

After the controller 18 is initialized, (100),
A signal is read from the sensor 16 that detects a kickdown (101), and it is determined whether or not there is a kickdown (102). When I'm down,
Set the pressure value to increase the differential limit amount (1
03), and outputs a control signal (104).

When the kick-down is completed or when the kick-down is not completed, the steering angle is read (105), and the pressure P for giving the differential limiting amount according to the steering angle is calculated from the map (106), and this pressure is obtained. The current i required for this is calculated (107). control current i
is applied to the current-controlled pressure reducing valve 76 (104), and the differential of the differential limiting mechanism 12 is limited.

In this way, the differential is limited during kickdown, that is, when starting and accelerating, and it becomes possible to obtain sufficient traction.

When a directional control valve or a switching valve is provided in place of the current-controlled pressure reducing valve 76, it detects kick-down, limits the differential when kick-down,
The differential restriction should be canceled when the gear is not being pushed down.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the differential control device, FIG. 2 is a control flowchart, and FIG. 3 is a sectional view of the differential device. DESCRIPTION OF SYMBOLS 10... Differential control device, 12... Differential limiting mechanism, 14... Differential device, 16... Kickdown detection sensor, 18... Controller, 20... Operating means, 76... Current control pressure reducing valve, 84 ...Rudder angle sensor, 86...Vehicle speed sensor.

Claims (1)

[Scope of utility model registration request] A device for controlling the differential of the differential device in a vehicle equipped with an automatic transmission and a differential device having a differential limiting mechanism, the device comprising: a sensor for detecting a kick-down state of the automatic transmission; A differential control device comprising: a controller receiving a signal; and operating means controlled by the controller for operating the differential limiting mechanism to limit the differential when kicking down.