JPS62237149A - Manual valve of automatic speed change gear for 4-wheel drive with auxiliary speed change gear - Google Patents

Abstract

PURPOSE:To make a vehicle provided with the manual valve in the caption become fail-safe, by moving a valve body by means of a stand-by switching mechanism when the switching power from an electric actuator to said valve body is cut off, and keeping it at a position where an oil path is constituted so as to establish a high speed running state. CONSTITUTION:When a selector switch 17 is operated, a controlling device 16 drives a step motor 14 to move a spool 3 in selected direction to switch a hydraulic pressure supply port 11 to connect with a discharge port or a closing port 10, 12, to establish either a high speed running state or a reduced speed 4-wheel driving state. And, if said step motor 14 fails to function because of an abnormal occurrence such as breaking of wire, said spool 3 moves to the right by a compression spring 18, which is provided as a stand-by switching mechanism, and keeps the position where an oil path is constituted to establish the high speed running state. Thus, for vehicle provided with said manual valve, whenever an electric actuator fails, the high speed running state is established and kept, the vehicle becoming fail-safe.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a manual valve in an automatic transmission for four-wheel drive of a vehicle, and is particularly suitable for high-speed two-wheel drive or high-speed four-wheel drive in a high-speed drive state and a deceleration four-wheel drive state. The present invention relates to a manual valve for a four-wheel drive automatic transmission equipped with a switchable sub-transmission.

Prior art This type of automatic shift feeling is described in, for example, Japanese Patent Application No. 59-275483.
It is proposed by No. This connects the main transmission, which is connected to the engine via the torque converter, to the shift lever.
The output of the main transmission is automatically switched according to the selected range, throttle opening, vehicle speed, etc., and the output of the main transmission is switched between high speed (reduction ratio = 1) and deceleration (reduction ratio > 1) in the sub transmission. The configuration is such that the output of the sub-transmission is transmitted to either or both of the front export power shaft and the rear export power shaft. Conventionally, there are generally two shift levers: one for the main transmission, and one for switching the sub-transmission between high-speed two-wheel drive (H2>, high-speed four-wheel drive (H4), and deceleration four-wheel drive (L4)). - are provided, and a drive state that matches the driving conditions is selected by these two shift levers, and manual valves connected to each shift lever are operated to switch.

Problems to be Solved by the Invention In the above-mentioned conventional automatic transmission, the shift lever is installed in the driver's seat, and this is connected to the manual valve by a wire or link. It is difficult to operate and position the two shift levers without damaging the operation, and there is a risk that the installation position will be difficult due to interaction with other operating equipment. Additionally, wires and link devices that transmit the movement of the shift lever to the manual valve are difficult to handle and arrange. In order to solve this problem, it is conceivable to configure the manual valve for the auxiliary transmission among the manual valves described above to be operated by a motor, and with such a configuration, the switching operation of the auxiliary transmission can be performed. This can be done by operating a switch, so the number of shift levers can be reduced to one, and the wires and link devices associated with it can also be omitted. However, when controlling electrically, there is a slightly higher risk of inoperability due to disconnection or poor connection than with multi-region control, so manual valves are controlled electrically via a motor as described above. In order to control the reliability, it is desirable to take sufficient measures for reliability. The reality is that so far, these points have not been paid attention to or taken into consideration.

In view of the above-mentioned circumstances, this invention automatically switches a valve body in an automatic transmission with an auxiliary transmission for four-wheel drive to set the oil passage configuration in a direction that increases the reliability of the drive state in the event of an abnormality. The purpose is to provide a manual valve that can

Means for Solving the Problems In order to achieve the above object, the present invention provides an auxiliary switching mechanism that can operate an electric actuator, and when the switching force applied to the valve body by the electric actuator is released. The auxiliary switching mechanism is characterized in that the valve body is operated and held at a position where the oil passage configuration is set to a high-speed drive state.

Function: In the manual valve of the present invention, when the electric actuator is driven by a switch, for example, the valve body moves in a predetermined direction, and as a result, the port to which hydraulic pressure is supplied and the port to be discharged or closed are connected. Accordingly, the vehicle is set to either a high-speed drive state or a decelerated four-wheel drive state. When the electric actuator ceases to operate due to an abnormality such as a wire breakage, the auxiliary switching mechanism operates the valve body and moves and holds the valve body in a position where an oil passage configuration for setting a high-speed drive state is established. That is, in a vehicle equipped with the manual valve of the present invention, when the electric actuator becomes inoperable, the vehicle is always in a high-speed driving state.

Example The present invention will be explained in detail below.

FIG. 1 is a schematic diagram showing the overall configuration of a manual valve 1 according to the present invention, and FIG. 2 is a schematic diagram of a four-wheel drive automatic transmission with an auxiliary transmission. First, the configuration of the manual valve 1 shown in FIG. First, second, and third lands 4, 5.6 are formed from the right side of the spool 3, and a rod 7 is formed on the proximal end surface of the spool 3 (the left end surface in FIG. 1), and a rack 8 is attached to the rod 7. is formed. On the other hand, the valve body 2 is formed with a first drain port 9 that communicates with the oil on the tip side from the first land 4, and a C4 port for establishing an oil passage configuration for setting the four-wheel drive state. 10, a line oil pressure supply port 11, an H port 12 for establishing an oil passage configuration for setting a high-speed drive state, and a second drain port 13 are formed in the order listed here from the right side of FIG. Note that the distance between the C4 port 10 and the H port 12 is smaller than the distance between the first land 4 and the second land 5 on the spool 3 so that these ports 10°12 communicate with the line oil pressure supply port 11 at the same time. It is set.

A pinion 15 attached to the rotating shaft of a step motor 14 is engaged with the rack 8, and the step motor 14 is connected to a control device 16 such as a microcomputer. In addition to various control data such as the shift position, a setting signal from a manual selection switch 17 is input. That is, the manual selection switch 17 selects high-speed two-wheel drive (H2), high-speed four-wheel drive (H4), and deceleration four-wheel drive (L).
4), and the control device 16 is configured to rotate the step motor 14 by a predetermined amount in a predetermined direction based on a signal input from the manual selection switch 17. More specifically, when high-speed two-wheel drive (H2) is selected, the spool 3 is connected so that the line oil pressure supply port 11 communicates only with the H port 12.
The step motor 14 rotates to move the spool 3 further to the left than the state shown in the figure, and when high-speed four-wheel drive (H4) is selected, the step motor 14 rotates to move the spool 3 to the state shown in the figure. Roughly reduced four-wheel drive (L4
), the line oil pressure supply port 11 is set to C4.
The step motor 14 rotates to move the spool 3 further rightward from the illustrated state so that it communicates only with the port 10.

A compression spring 18 as an auxiliary switching mechanism is disposed at the oil outlet on the tip side (right side in FIG. 1) of the first land 4. When the step motor 14 is rotated to move the spool 3, the compression spring 18
The elastic force is set so that the spool 3 can be pushed and compressed, and when the power to the step motor 14 is cut off, the spool 3 can be pushed and the step motor 14 rotated, and the spool 3 can be further pushed back. The stroke is set to a stroke that moves the spool 3 to a position where the line oil pressure supply port 11 communicates only with the H port 12.

High-speed two-wheel drive (H2
The structure of the automatic transmission 19 with an auxiliary transmission that can be switched between high-speed four-wheel drive (H4) and deceleration four-wheel drive (L4) is shown in FIG. This second figure is from the above mentioned patent application No. 59-2754.
The main transmission 2 is a simplified version of the configuration shown in the drawing of No. 83, and has multiple forward gears and one reverse gear.
0 is connected to the engine 22 by disconnecting the torque converter 21, and the output shaft of the main transmission 20 is connected to the auxiliary transmission 2.
3 input 11124. This input shaft 24 is directly connected to a sun gear 25 of a planetary gear mechanism, and is also connected to a planetary carrier 26 via a hydraulic clutch C3. Further, a hydraulic brake B4 for stopping the rotation of the ring gear 28 is provided between the ring gear 28 meshing with the pinion 27 and a fixed part 29 such as a casing.

The rear export force shaft 30 is directly connected to the carrier 26,
A power transmission mechanism 31 is connected to the rear wheel 26 via a hydraulic clutch C4 for switching between two-wheel drive and four-wheel drive. The power transmission mechanism 31 is for transmitting a moving horn to the front export force shaft 32, and is composed of, for example, a pair of sprockets and a chain wrapped around the sprockets. In other words, each drive state of high-speed two-wheel drive (H2), high-speed four-wheel drive (H4), and deceleration four-wheel drive (L4) is controlled by the clutch C3 described above.
, C4 and brake B4, which is achieved by engaging and disengaging clutches C3, C4 and brake B4.
Table 1 shows the relationship between the engagement/disengagement and the driving state.

Table 1 A hydraulic circuit for operating each clutch C3, C4 and brake B4 in the combination state shown in Table 1 based on the switching operation of the manual valve 1 shown in FIG.
The hydraulic circuit shown in FIG. 5 in No. 9-275483M can be adopted. According to the hydraulic circuit, basically, the line hydraulic pressure supply port 11 of the manual valve 1 is communicated only with the C4 port 10, and the H port 12 is connected to the C4 port 10.
If it communicates with the second drain port 13, the deceleration four-wheel drive (
L4) state, and the line oil pressure supply port 11 is set to C.
If it communicates with both 4 port 1Q and H port 12, high-speed four-wheel drive (H4) is achieved, and by communicating only the line oil pressure supply port 11 with H port 12,
0 to the first drain port 9, high-speed two-wheel drive (
H2).

The oil passage configuration for each drive state can be set by operating a switch. That is, the control will be explained with reference to the flowchart shown in FIG. 3. When one of the drive states is selected by the aforementioned selection switch 17, it is first determined whether or not deceleration four-wheel drive (L4) is selected. , in the case of "yes", the number of steps for L4 is determined. rL4 again? The result of J's judgment process is ``
If the answer is "No", it is determined whether high-speed four-wheel drive (H4) has been selected. If the result is "yes", move the spool 3 from the current position to the position shown in FIG.
The number of steps for H4 required to move to a position where it communicates with both ports 12 is determined. On the contrary, if the determination result is "no", the number of steps for H2 required to move the spool 3 from the current position to a position where the line oil pressure supply port 11 communicates only with the H port 12 is determined.

When the number of steps corresponding to the drive state selected by the selection switch 17 is determined, the determined number of pulse signals are sent from the control device 16 to the step motor 14.
Output to. As a result, spool 3 is connected to step motor 1.
4 to a predetermined position to communicate the line oil pressure supply port 11 with either or both of the C4 port 10 and the H port 12, and accordingly each clutch C3, C4, and Brake B4 is engaged and released in combinations shown in Table 1. Note that determining the number of steps involves determining the distance required to move the spool 3 from the current position to the desired position, so it naturally includes determining the current position of the spool 3. If the current position corresponds to the selected drive state, the number of steps becomes zero and the step motor 14 does not rotate. Furthermore, as described above, when the hydraulic circuit in Japanese Patent Application No. 59-275483 is used, the solenoid valve is controlled together with the step motor 14 by the control device 16 to switch the oil path, resulting in a high-speed drive state or a deceleration drive state. Set as appropriate for the oil passage configuration.

The operation of the spool 3 by the step motor 14 described above is performed against the elastic force of the compression spring 18, but if an abnormality such as a disconnection of the wiring or a failure of the step motor 14 occurs, the driving force of the step motor 14 is reduced. When it is exhausted, only the pressing force by the compression spring 18 acts on the spool 3, so the spool 3 is
Pushed to the left in the figure, move the line oil pressure supply port 11 to the position where the oil passage configuration for high-speed two-wheel drive (H2) is set.
Move to a position where it communicates only with port 12.

That is, if an abnormality occurs in the step motor 14 or its associated electrical system, the vehicle is set and maintained in the high-speed two-wheel drive (H2) state. Therefore, for example, if the above-mentioned abnormality occurs while driving, there will be two drive wheels, and the rotation speed will remain the same or increase.
At least no braking phenomenon or accompanying tire slipping occurs.

As explained with reference to Fig. 3, the determination process only requires two steps, so only two selection switches are required, and the limit position of the spool movement by an auxiliary switching mechanism such as a compression spring can be set to a high-speed two-wheel drive. If the position is set to the oil path configuration for setting the (H2) state, the spool can be moved by the auxiliary switching mechanism instead of the step motor when high-speed two-wheel drive (H2) is selected.

Further, in the present invention, a DC motor and a position detector may be used instead of the step motor to control the movement of the spool to a desired position. In general, the auxiliary switching mechanism can adopt various configurations. For example, instead of using the compression spring, line hydraulic pressure is supplied from the first drain port 9 in the event of some abnormality to suppress the spool in the left direction in FIG. 1. It may also be configured to be moved. Furthermore, it goes without saying that the power transmission mechanism between the motor and the spool is not limited to the rack 8 and pinion 15 shown in the above embodiment. The manual valve of the present invention can be used as long as it can set the oil passage configuration for at least high-speed two-wheel drive and deceleration four-wheel drive, so there is no need for it to be a direct-acting spool valve. Instead, it may be a rotary type valve.

Effects of the Invention As is clear from the above explanation, according to the present invention, each drive state such as high-speed two-wheel drive or deceleration four-wheel drive can be set by electrical control, so that it is possible to set various drive states such as high-speed two-wheel drive and deceleration four-wheel drive. By eliminating the need for a shift lever and its associated link mechanism, and by providing an auxiliary switching mechanism that sets the system to high-speed drive in the event of an electrical system failure, etc.
It is possible to establish reliability in the event of an abnormality, that is, failsafe.

[Brief explanation of drawings]

FIG. 1 is a strategic diagram showing the structure of a body groove according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of an automatic transmission method for four-wheel drive with an auxiliary transmission controlled by the manual valve, and FIG. 3 is a control flowchart of the step motor. 1...Manual valve, 2...Valve body,
3...Spool, 10...C4 port, 11.
...Line hydraulic supply port, 12...H port,
14... Step motor, 16... Control device,
17...Selection switch, 18...Compression spring, 1
9... Automatic transmission, 28... Sub-transmission, 30.
...Rear export force axis, 32...Front export force axis, B4...
Brake, C3゜C4...Clutch. Figure 3

Claims (1)

[Claims] By operating the valve body with an electric actuator, the port for supplying hydraulic pressure and the port for discharging or closing the hydraulic pressure can be switched between a high-speed two-wheel drive or high-speed four-wheel drive state and a deceleration four-wheel drive state. In the manual valve, the valve body is moved to a position where the oil passage configuration is set to a high-speed driving state when the switching force applied to the valve body by the electric actuator is released. A manual valve for a four-wheel drive automatic transmission with an auxiliary transmission, characterized by having an auxiliary switching mechanism for holding the transmission.