JPS641698B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hydraulic clutch connection control device for a power shift transmission, and more particularly, the present invention relates to a hydraulic clutch connection control device for a power shift transmission. In order to adjust the supply speed and timing of hydraulic fluid to the hydraulic clutch, an electromagnetic proportional pressure control valve for the clutch is installed in the pipeline between the selector valve of the clutch connection means and the hydraulic pump. This invention relates to improvements in a hydraulic clutch connection control device which is provided with a control unit that receives a clutch switching command and outputs an opening degree signal and an opening time signal to a clutch electromagnetic proportional pressure control valve according to the load condition of the vehicle. It is something.

[Conventional technology]

In a power shift type transmission, a hydraulic clutch is provided for each transmission shift of power. However, in general, a hydraulic pressure control device is used to supply hydraulic fluid for connecting the hydraulic clutch in order to reduce the shock when the clutch is engaged, but there is a loss in the pipeline up to the hydraulic clutch, and the loss exceeds that loss. Since the hydraulic fluid must be supplied at a filling pressure, it takes time to initially fill the hydraulic clutch with the hydraulic fluid, making the connection operation redundant and hindering the agile movement of the vehicle.

To solve this problem, some hydraulic clutches have modulating valves interposed in the pipelines to each hydraulic clutch. Although not shown, this modulating valve consists of a main flow path, a bypass flow path, and a spool that switches between each flow path.The movement of the spool increases the filling pressure of the working fluid and shortens the filling time. It is becoming possible to do this.

However, in a hydraulic control device that employs such a modulating valve, the valve must be interposed in the pipeline for each hydraulic clutch, which requires space and increases costs. There is a drawback. In addition, the shape of the fluid path of the valve is specified, and the pressure loss of the working fluid flowing through it is determined, and the filling pressure and its time are uniquely determined by mechanical factors. As a result, there is a drawback that it cannot be operated flexibly depending on the load condition of the vehicle. Furthermore, depending on the machining accuracy of the liquid path, there is a drawback that the reliability of control cannot be guaranteed, such as that the initial filling pressure and time cannot be secured.

As a solution to these drawbacks, there is a hydraulic clutch connection control device for a power shift type transmission proposed by the present applicant in Japanese Patent Publication No. 58410/1983. This device 1 will be briefly described below with reference to FIG. When the driver performs a clutch switching operation, for example, when decelerating from F2 shift, which is a high forward speed, to F1 shift, which is a low forward speed, the driver must first apply the brakes to decelerate the vehicle to a certain speed, and then use the selector valve. Switch the manual directional control valve 2 from position M to N. At this time,
The switching signal is input to the control unit 3, and the shift switching modes shown in FIG. Of the filling time Aij and opening degree Bij signal, the corresponding filling time A2
1 and the opening degree B21 are automatically selected. These signals A21 and B21 are output to one electromagnetic proportional pressure control valve 6 interposed in a conduit 5 between the switching valve 2 and the hydraulic pump 4.

As a result, the control valve 6 operates according to the input control signals to ensure a desired initial filling pressure, and then opens to reach the clutch engagement starting pressure. The supply of hydraulic fluid from the hydraulic pump 4 is then maintained until the hydraulic clutch 7d in the power shift transmission 7 is completely switched to the desired hydraulic clutch 7c. Note that the filling time Aij and the opening degree Bij are determined based on vehicle-specific values determined in advance through experiments, etc., so that clutch switching is performed smoothly for all switching modes of the shift before switching and the shift after switching. It is something.

[Problem to be solved by the invention]

With the hydraulic clutch connection control device as described above, the initial objectives can be achieved. By the way, when a driver performs a deceleration operation or a reverse operation, he or she may forcefully switch the brakes without operating the brakes in order to move the vehicle more quickly or to reduce the troublesome operation. Therefore, considering the actual situation of such operation, it is necessary to increase the absorption energy capacity of each clutch plate.
The hydraulic clutch must be large or expensive. In addition, if a multi-stage shift (not shown) is adopted in which the speed ranges for both forward and backward travel are 1 to 4, in an extreme case, the driver may accidentally shift from the F4 shift state, which is the maximum forward speed, to the maximum reverse speed. There is a problem that the clutch plate may not be able to absorb high energy and be damaged due to switching to R4 shift.

By the way, Special Publication No. 1986-47427, Special Publication No. 1983
43146 and Japanese Patent Publication No. 53-3033 disclose a speed change control device for a transmission equipped with electrically controlled fluid friction elements (clutches, brakes, etc.). In order to eliminate shock and sluggishness (time lag) during gear shifting and achieve smooth gear shifting, these systems are designed to monitor the driving conditions of the vehicle.
Publication No. 47427 describes the transmission input shaft rotation speed, Japanese Patent Publication No. 54-43146 describes the engine throttle opening, and Publication No. 53-3033 describes the engine rotation speed.
The transmission input speed, torque, and transmission output speed are detected, and the fluid supply to the fluid friction elements during the shift transition period is temporally controlled in accordance with these. The above-mentioned proposal in Japanese Patent Publication No. 62-58410 is a hydraulic clutch connection control device for a power shift transmission with a different configuration to achieve the same objective.

However, in vehicles with power shift transmissions, such as wheel loaders, unlike automobiles and trucks with the transmissions described in the above-mentioned publication, it is difficult to change directions when running at full throttle at high speeds, for example from forward to reverse. Or constantly use forward movement from reverse. For example, when switching from forward to reverse, the reverse clutch is connected while the vehicle is running forward, so the inertial energy of the vehicle is absorbed as frictional energy of the clutch plate of the transmission. The clutch of a power shift transmission must be able to absorb a large amount of energy in order to withstand such harsh use, but if the vehicle speed is too high when changing direction, the inertial energy of the vehicle will be absorbed by the clutch plate. This can cause the clutch plate to seize, etc., exceeding the allowable value.

The present invention was made to solve the above-mentioned problem, and when the clutch is switched by the selector valve to perform deceleration operation or reverse operation, the driver does not have to apply the brake, and the energy absorption capacity is small. In order to smoothly switch and connect the hydraulic clutch without causing damage to the clutch plate, in other words, to improve the inconvenience mentioned in Japanese Patent Publication No. 62-58410, the braking device normally attached to vehicles ( It is an object of the present invention to provide a hydraulic clutch connection control device for a power shift type transmission that can operate a vehicle brake (vehicle brake) in conjunction with transmission connection control.

[Means to solve the problem]

As shown in FIG. 3 or 6, the hydraulic clutch connection control device for a power shift type transmission according to the present invention includes select valves 2, 2a to 2.
d to supply hydraulic fluid to each hydraulic clutch of the hydraulic control device which connects the hydraulic clutches 7, 7a to 7d provided for each shift of the power shift transmission. In order to control the speed and hydraulic pressure, a control unit 13 outputs control signals in accordance with pre-stored control data for each shift of the respective hydraulic clutch in response to shifts of the power shift transmission. A clutch electromagnetic proportional pressure control valve 6 is provided and controls the opening degree in response to the control signal.
is applied to the hydraulic clutch connection control device interposed in the line 5 between the selector valves 2, 2a to 2d and the hydraulic pump 4.

Its features include a speed detection means 14 that detects the speed of the vehicle and outputs a vehicle speed signal to the control unit 13, and a signal from the control unit 13 that operates the hydraulic brake 15 of the brake operation means 12. Pressure source 1
6, and a brake electromagnetic proportional pressure control valve 17 that supplies working fluid from the hydraulic clutches 7, 7a.
A hydraulic clutch of a power shift type transmission in which braking is automatically started according to the vehicle speed before the engagement of the hydraulic clutches 7, 7a to 7d, and the amount of energy absorbed by the clutches can be reduced when the hydraulic clutches 7, 7a to 7d are engaged. This is because it is a connection control device.

〔Effect of the invention〕

As described in detail above, the present invention is configured so that the brake actuating means can be automatically actuated by a selected signal from the control unit to the clutch connecting means, so that deceleration operation and reverse movement operation using the selector valve can be performed. Even if the driver does not directly operate the brakes, the clutch plate, which has a small energy absorption capacity, can be operated safely and smoothly without causing any damage.
Therefore, it is possible to use a hydraulic clutch with a small energy absorption capacity, making it possible to downsize the device, improve durability, and reduce costs.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples. FIG. 3 is an overall system diagram of a hydraulic clutch connection control device 10 for a power shift transmission, which is roughly divided into a clutch connection means 11 and a brake actuation means 12, and a system for controlling each of these means 11 and 12. A control unit 13 and vehicle speed detection means 14 are provided.

Specifically, the clutch connecting means 11 includes a manual directional control valve 2 which is a selector valve to adjust the supply speed and timing of the hydraulic fluid to each hydraulic clutch 7a to 7d of the power shift transmission 7. and the hydraulic pump 4.
One clutch electromagnetic proportional pressure control valve 6 is interposed in the clutch, and upon receiving a clutch switching command, the control valve 6 is filled in a manner similar to that shown in FIG. 2 described above. A control unit 13 is provided which outputs the time Aij and the degree of opening Bij.

In addition, a vehicle speed detecting means 14 is provided for detecting the speed of the vehicle and outputting a vehicle speed signal to the control unit 13, and further for operating a hydraulic brake 15 using pneumatic or hydraulic pressure as the brake operating means 12. A brake electromagnetic proportional pressure control valve 17 is provided which receives signals from the control unit 13 and supplies working fluid from the pressure source 16. Note that this control valve 1
7 is an opening degree signal Cijk as shown in FIG. 4a, which is stored in advance in the control unit 13.
and operates in response to the opening time signal Dijk,
Further, the valve is opened in response to an opening degree signal Cij as shown in FIG. 4b, and closed when the vehicle speed detected by the vehicle speed detection means 14 matches the valve closing vehicle speed signal Eij.

Such a brake operating means 12 is capable of braking by a manual braking system branched off via the shuttle valve 18 in addition to the above-mentioned automatic braking system. That is, in this manual braking system, braking is performed by opening the control valve 20 when the driver depresses the brake pedal 19 as necessary, independently of the operation of the clutch connecting means 11 and the brake operating means 12 described above. It is intended to make it possible to In addition, 21 in the figure
is a booster that amplifies the working fluid pressure and doubles the braking force, and is provided as necessary.

When the brake actuation means 12 as described above is provided, it is necessary to link the operation of the clutch connection means 11 with the operation of the brake actuation means 12 in some way. As shown, a time delay signal Fij is stored in addition to the aforementioned filling time signal Aij and opening degree signal Bij for the electromagnetic proportional pressure control valve 6 for the clutch, and the electromagnetic proportional pressure control valve 6 for the clutch is connected to the electromagnetic proportional pressure control valve 6 for the brake. When the proportional pressure control valve 17 starts operating after a predetermined period of time has elapsed after the proportional pressure control valve 17 started operating, or when the vehicle speed detected by the vehicle speed detection means 14 matches the valve opening start vehicle speed signal Gij as shown in FIG. 5b. The opening is now activated.

As shown in FIG. 6, instead of the manual directional control valve 2 as a selector valve, one electromagnetic directional control valve 2a to 2d is provided for each hydraulic clutch, and the driver's commands are input. It may be provided with a command box 22 which outputs an operation command signal to the control unit 13 and the electromagnetic directional control valves 2a to 2d corresponding to the command.

According to such a configuration example, it can be operated as follows. The operating procedure will be explained with reference to the flowchart shown in FIG.

First, the brake electromagnetic proportional pressure control valve 17 is
The clutch electromagnetic proportional pressure control valve 6 operates in response to the opening degree signal Cijk and the opening time signal Dijk as shown in FIG. 4a, which are stored in the control unit 13 in advance. The filling time signal shown in Figure 5a
This paper describes a hydraulic clutch connection control device for a power shift transmission that operates in response to Aij, opening degree signal Bij, and time delay signal Fij.

For example, suppose that the driver switches the manual directional control valve 2 from position M to N so as to shift from F2 shift, which is a high forward speed, to F1 shift, which is a low forward speed. This position switching signal is automatically transmitted from the manual directional control valve 2 to the control unit 13. At this time, the shift before switching and the shift after switching are input to the control unit 13 (steps 1 and 2 of the flowchart, hereinafter referred to as S1, etc.), and the vehicle speed detected by the vehicle speed detection means 14 is inputted to the control unit 13. is also input to the control unit 13 (S3). On the other hand, even if the shift before switching is F2, the vehicle at that time can take various speeds, so the control unit 13 is programmed to determine whether the vehicle is traveling in the shift before switching in each shift switching mode as shown in FIG. 4a. The obtained speed is subdivided into, for example, every 5 km/h, and the opening degree signal of the electromagnetic proportional pressure control valve 17 for the brake is generated accordingly.
Cijk and opening time signal Dijk are automatically selected. Therefore, if the vehicle speed before switching is, for example, 23km/
h, the control unit 13
Vehicle speed in F2 to F1 switching mode of 20~25
An opening degree signal C215 in Km/h and an opening time signal D215 are output to the brake electromagnetic proportional pressure control valve 17. As a result, the control valve 17 opens to a predetermined opening degree (S4), and the working fluid from the pressure source 16 passes through the shuttle valve 18 and the booster 21 to operate the hydraulic brake 15 (S5).

After the opening state of the brake electromagnetic proportional pressure control valve 17 is maintained for the predetermined opening time output from the control unit 13 (S6), this control valve 1
7 is closed (S7), and the operation of the hydraulic brake 15 is released (S8). Therefore, even if the driver does not press the brake pedal 19, the vehicle speed is automatically reduced to such a level that the hydraulic clutch can be switched from 7d to 7c. In parallel with such braking by the brake operating means 12, the control unit 13 commands the clutch connecting means 11 to operate. That is, various loads of the vehicle such as the engine speed and the amount of acceleration at that time are input to the control unit 13 (S9), and the switching mode from F2 to F1 shown in FIG. 5a, which is stored in the control unit 13 in advance, is entered. The operation start delay time signal F21 of the applied electromagnetic proportional pressure control valve 6 for the clutch to the electromagnetic proportional pressure control valve 17 for the brake, its filling time signal A21, and the opening degree signal B21 corresponding to the filling pressure required at that time. are automatically selected and output to the clutch electromagnetic proportional pressure control valve 6. the result,
When a predetermined delay time has elapsed (S10), the control valve 6 opens to a predetermined opening degree (S11), and a predetermined hydraulic clutch 7c is switched and connected (S1).
2), the control valve 6 closes after a predetermined period of time has elapsed;
Clutch switching operation is completed.

In this operation example, forward deceleration switching from F2 shift to F1 shift was described, but when the F2 shift is at a low speed of 8 km/h, for example, in order to maintain or slightly reduce this speed and increase the propulsion torque, the F1 shift is performed. In the case of switching to forward or reverse, the output signal is selected by the control unit 13, and the same operation as described above is performed. Incidentally, even in the case of speed increase switching in the same direction of travel, the same operation as described above is performed in response to a signal selected by the control unit 13, but it is generally not necessary to operate the brake actuating means 12. Cij, Dij, and Fij in the speed-up switching modes of FIGS. 4a and 5a are not output as indicated by - in the figures.

Next, the brake electromagnetic proportional pressure control valve 17 is
The valve is opened in response to an opening degree signal Cij as shown in FIG. , and the clutch electromagnetic proportional pressure control valve 6 is
A hydraulic clutch connection control device for a power shift type transmission will be described which operates to open the valve when the vehicle speed detected by the vehicle speed detecting means 1 matches the valve opening start vehicle speed signal Gij as shown in FIG. 5b. The operating procedure will be explained with reference to the flowchart shown in FIG.

Assume that the driver switches the manual directional control valve 2 from position M to N so as to shift from F2 shift, which is a high forward speed, to F1 shift, which is a low forward speed. The shift before switching and the shift after switching are input to the control unit 13 (S21, S22), and the vehicle speed detected by the vehicle speed detection means 14 is also input to the control unit 13 (S2
3). At this time, the control unit 13 outputs an opening degree signal for the brake electromagnetic proportional pressure control valve 17 from among the switching modes shown in FIG. 4b.
Cij and the valve closing vehicle speed signal Eij when it should be closed are selected, and the brake electromagnetic proportional pressure control valve 17 opens in response to the opening degree signal C21 in S24. As a result, the hydraulic brake 15 is activated (S25), and the vehicle speed is reduced. Vehicle speed detection means 1
4, the detected vehicle speed is finally input to the control unit 13 (S23), and the braking operation is maintained until the vehicle speed at which the control valve 17 should be closed is detected (S26).

When the vehicle speed reaches a predetermined speed that is the valve closing vehicle speed signal E21 (S27), the control valve 17 is closed (S28) and the operation of the hydraulic brake 15 is released (S29). Therefore, even if the driver does not press the brake pedal 19, the hydraulic clutch will
The vehicle speed is automatically reduced to a point where it is safe to switch to In parallel with the braking by the brake actuating means 12, the control unit 13
The clutch connecting means 11 is commanded to operate. That is, various loads of the vehicle such as the engine speed and the amount of acceleration at that time are inputted to the control unit 13 at step S30, and the control unit 13 selects F2 from among the switching modes stored in advance as shown in FIG. 5b. The valve opening start vehicle speed signal G21 of the clutch electromagnetic proportional pressure control valve 6 applied to the switching mode from shift to F1 shift is selected. The detected vehicle speed is inputted to the control unit 13 from the vehicle speed detection means 14 (S23), but the control valve 6 is not operated until a predetermined vehicle speed is detected (S31). When the vehicle speed reaches a predetermined speed (S32), the filling time signal A21 selected in the control unit 13 and the opening degree signal B21 corresponding to the filling pressure required at that time are sent to the electromagnetic proportional pressure control valve 6 for the clutch. Output. As a result, the control valve 6 opens to a predetermined opening degree (S33), and the predetermined hydraulic clutch 7c
connection is made (S34), and after a predetermined time has elapsed, the control valve 6 is closed and the switching operation of the clutch is completed.

Note that the predetermined speed of the clutch connecting means 11 in step 32 described above may be the same as the predetermined speed of the brake actuating means 12 in step 27, but the predetermined speed of the former control valve 6 may be slightly higher than that of the latter. By setting this, a series of operations can be performed even more quickly. In addition, even if the driver depresses the brake pedal 19 to activate the manual braking system described above during the above-mentioned operation, the vehicle speed braked thereby is detected by the vehicle speed detection means 14, This is immediately reflected in the actuation of the brake actuating means 12 and the clutch connecting means 11, resulting in a potentially faster switching connection of the hydraulic clutch without any disturbance to the respective actuation.

According to the above procedure, the clutch connecting means 1
1 and the brake actuating means 12, the brake electromagnetic proportional pressure control valve 17 is operated by the fourth valve which is stored in advance in the control unit 13.
The clutch electromagnetic proportional pressure control valve 6 operates in response to the opening degree signal Cijk and the opening time signal Dijk as shown in FIG. In some cases, the opening operation is performed when the valve opening start vehicle speed signal Gij coincides with the opening degree signal Gij, or when the brake electromagnetic proportional pressure control valve 17 matches the opening degree signal Cij as shown in FIG. and closes when the vehicle speed detected by the vehicle speed detection means 14 matches the valve closing vehicle speed signal Eij,
In addition, the clutch electromagnetic proportional pressure control valve 6 may be operated in response to the filling time signal Aij, opening degree signal Bij, and time delay signal Fij shown in FIG. 5a stored in the control unit 13.
It will be readily understood that these operations can be performed by interchanging the clutch connecting means 11 and the brake operating means 12 in the two flowcharts described above.

As can be seen from the explanation of the operation in such an example, the driver does not have to apply the brakes at all when switching from the F2 shift for high speed forward speed to the F1 shift for low forward speed as described in the conventional technology section. The brake actuating means 12 is then actuated to reduce the vehicle speed, and the desired hydraulic clutch switching is effected smoothly without imposing a large energy absorption load on the clutch plate. Although not shown, deceleration switching occurs when a multi-stage shift is adopted in which the forward and reverse speed ranges are 1 to 4, or in extreme cases, when the driver shifts from the F4 shift state, which is the highest forward speed. Even if you accidentally switch to the R4 shift, which is the highest reverse speed, the control unit outputs a signal corresponding to the switching mode, so there is no possibility that the clutch plate will not be able to absorb the high energy and will be damaged. Avoided. In other words, when changing direction, the vehicle speed is detected, and if the speed exceeds the clutch's allowable absorption energy, the braking device is activated before the transmission is engaged, reducing the vehicle speed to below the allowable speed. Only then can transmission connection control be implemented and direction changes can be made smoothly and quickly without causing damage to the equipment.

[Brief explanation of drawings]

Figure 1 is a control system diagram of the prior art in a power shift type transmission hydraulic control device;
The figure shows the setting diagram of the operation command signal for each switching mode stored in the control unit of the device.
FIG. 3 is a control system diagram of a power shift type transmission hydraulic control device according to an embodiment of the present invention, and FIGS. 4a and 4b show operating commands to the brake operating means in each switching mode stored in the control unit. Signal setting diagrams; Figures 5a and 5b are diagrams of setting actuation command signals to the clutch connecting means in each switching mode stored in the control unit; Figure 6 is a partial control system of an embodiment with different selector valves. 7 is a flowchart showing one example of the operation, and FIG. 8 is a flowchart showing another example of the operation. 2, 2a to 2d... Selector valve, 4... Hydraulic pump, 5... Pipeline, 6... Electromagnetic proportional pressure control valve for clutch, 7, 7a to 7d... Hydraulic clutch, 10... Power shift hydraulic clutch connection control device for a hydraulic transmission, 11...clutch connection means, 12...brake actuation means, 13...
Control unit, 14...vehicle speed detection means,
15...hydraulic brake, 16...pressure source, 1
7...Electromagnetic proportional pressure control valve for brake, Cijk,
Cij, Bij...Opening degree signal, Dijk...Opening time signal, Eij...Valve closing vehicle speed signal, Aij...Filling time signal, Fij...Time delay signal, Gij...Valve opening start vehicle speed signal.

Claims (1)

[Scope of Claims] 1. Operation of each hydraulic clutch of a hydraulic control device that supplies hydraulic fluid through a select valve and connects a hydraulic clutch provided for each shift of a power shift transmission. A control that outputs control signals in accordance with pre-stored control data for each shift of each hydraulic clutch in response to shifts of the power shift transmission to control fluid supply rate and fluid pressure. A clutch electromagnetic proportional pressure control valve which receives the control signal and controls the opening degree of the power shift type transmission is provided with a clutch electromagnetic proportional pressure control valve which controls the opening degree in response to the control signal. The clutch connection control device includes vehicle speed detection means for detecting the speed of the vehicle and outputting a vehicle speed signal to the control unit, and a pressure source that receives a signal from the control unit to operate a hydraulic brake of the brake operation means. Braking is automatically started according to the vehicle speed before the hydraulic clutch is connected, and when the hydraulic clutch is connected, the amount of energy absorbed by the clutch is reduced. A hydraulic clutch connection control device for a power shift transmission, which is characterized by its ability to be made smaller. 2. The power shift type transformer according to claim 1, wherein the brake electromagnetic proportional pressure control valve operates in response to an opening degree signal and an opening time signal stored in advance in the control unit. Mission's hydraulic clutch connection control device. 3. The brake electromagnetic proportional pressure control valve opens in response to an opening degree signal stored in advance in the control unit, and closes when the vehicle speed detected by the vehicle speed detection means matches the valve closing vehicle speed signal. A hydraulic clutch connection control device for a power shift type transmission as claimed in claim 1. 4. The clutch electromagnetic proportional pressure control valve operates in response to a filling time signal, an opening degree signal stored in the control unit, and a time delay signal from the start of operation of the brake electromagnetic proportional pressure control valve. A hydraulic clutch connection control device for a power shift transmission according to claim 1. 5. The power shift type according to claim 1, wherein the clutch electromagnetic proportional pressure control valve opens when the vehicle speed detected by the vehicle speed detection means matches a valve opening start vehicle speed signal. Transmission hydraulic clutch connection control device.