JPS62278365A - Variable capacity transmission having torque converter and hydraulically drain speed change gear arranged in parallel - Google Patents

Abstract

PURPOSE:To make it possible optionally control the total capacity of a torque converter and a hydraulically driven speed change gear (HST), by constituting the HST with a variable displacement pump and a fixed displacement motor, and by controlling the discharge amount of the pump and a relief valve in an HST main circuit. CONSTITUTION:The speed ratio of a hydraulically driven speed change gear (HST) 4 having a variable displacement pump 5 and a fixed displacement motor 6 and provided in parallel with a torque converter 3 coupled to the output shaft of an engine 1, is controlled by controlling a swash plate control actuator 9 provided in the variable displacement pump 5. Further, a relief valve 7 for changing the relief pressure of an HST main circuit, is controlled by a computing section 8 together with the actuator 9. Further, the computing section 8 determines a HST pattern and a pump discharge amount in accordance with signals from an accelerator pedal, a type l to III change-over switch 12 and an HST power percent change-over dial 13.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention relates to a power transmission device for construction machinery, and in particular, the invention relates to a power transmission device for construction machinery, and in particular, the invention relates to a power transmission device for construction machinery. The present invention relates to a variable capacity transmission having the function of dividing the work into tasks to be carried out.

(Conventional technology) Conventional transmission equipment of this type.

(11 There is something like the one shown in Figure 5 (al).

In other words, it has a fixed capacity torque converter a and a fixed capacity gear pump b, where the fixed capacity torque converter a is used for the travel system d, the fixed capacity gear pump b is used for the work equipment system e, and C indicates the engine. .

(2) Another conventional device is a variable capacity torque converter with a sliding clutch as shown in FIG. 6 (al).

In the figure, a' is the torque converter, b' is the sliding clutch, C' is the engine, and the amount of N is the impeller rotation speed.
Let No be the engine rotation speed and Nt be the turbine rotation speed.

In this type of variable capacity torque converter with a slipping clutch, clutch slippage is controlled.

Ratio (N,
≧Ni), the absorption horsepower of the torque converter is variably controlled, and thereby the output of the torque converter is made variable, making it possible to distribute the output between the traveling system and the working machine system to some extent. FIG. 6('b) is a graph showing matching between the engine and torque converter, and No. 611 (cl) is a graph showing vehicle performance.

(3) Still another conventional device is shown in Fig. 7 (al.
Hydraulically driven transmission (H.

S, T).

In the figure, a" is the H3T main circuit and variable displacement pump b
'' and a hydraulic morph d'', e'' is a H3T swash plate angle control actuator, f'' is a pressure controller 1g'' is an H5
It is a T% switching dial, and C" indicates the engine.

In this hydraulic drive mission, H, S, T main circuit a
The circuit pressure is fed back to control the swash plate angle (discharge amount) of the HoS and T pumps, thereby controlling the speed ratio of H, S, and T. If the H, S, and T main circuit pressures can be selected independently and arbitrarily in addition to speed ratio control, it becomes a variable capacity transmission. Figure 7 (bl, (C
1 shows graphs of H, S, T control and vehicle performance, respectively.

(Problem that the invention attempts to solve) The conventional device as described above has the following problems.

(1) Regarding conventional equipment (a) There is little freedom in distributing engine output.

FIG. 5 (bl) is a graph of matching of the work machine pump, torque converter, and engine, and FIG. 5 (C) is a graph of vehicle performance.

As the engine speed decreases in the direction of the arrow in Figure 5 (bl), the work machine speed slows (and the work machine horsepower decreases.And when work machine horsepower is required, the force distributed to the traveling system decreases, When horsepower is required for the travel system, the distribution to the work equipment system will be reduced unless there is a work equipment priority circuit.

(b) It is not possible to select vehicle performance that suits the working conditions.

FIG. 5 fbl, (as is clear from the graph of C1.

Vehicle performance is designed to satisfy a certain level of work performance under all work conditions, so $! -It is of course difficult to find the best match if you only consider one working condition.

it is obvious.

Regarding the conventional device (2), a variable capacity torque converter with a slipping clutch has a problem with the durability of the clutch because the clutch always slips.

Regarding the conventional device (3), (a') When the capacities of H, S, and T become large, H, S, and T
There is a limit to the capacity of HoS, T to use H, S, and T for construction machinery that requires a slow control speed and fast response.

(b) Power transmission in the running system from the engine to the tires is
Although oil is used as a medium in the middle, overall it is similar to a rigid body, and the rotation between the engine and tires strictly corresponds in both directions, although there is a rotation ratio. Therefore, when exiting the vehicle or loosening the throttle pedal, the engine is driven in reverse due to the inertia of the vehicle body.

Especially when you release the throttle pedal suddenly.

Since construction machinery uses diesel engines with large pump losses, sudden engine braking is applied, and complex control is required to relieve this braking.

(c) When an auxiliary transmission is placed after H, S, and T.

It is difficult to operate for the same reason as in the previous section (b).

(Means and operations for solving the problems) This invention was made in view of the above problems, and includes a torque converter and H, S, and T (hydraulic drive transmissions) arranged in parallel. S and T are configured with a variable displacement pump and a fixed displacement motor to transmit power and control the speed ratio of the torque converter, and H, S and T main circuit relief valves and a calculation section are provided. The speed ratio of S and T is H
, S, T main circuit pressure can be controlled to arbitrarily select the relationship between the H, S, T speed ratio and the H, S, T main circuit pressure, and the overall capacity of the torque converter and H, S, T can be arbitrarily selected. It was designed so that it could be controlled.

(Example) Next, an example of the present invention will be described based on the drawings. FIG. 1 schematically shows the outline of its configuration, where l is an engine, 2 is a transmission, and 3 is a torque converter. 4 is HoS, T, which has a variable displacement pump 5 and a fixed displacement hydraulic motor 6. H, S, and T4 are partially responsible for power transmission, and the relief characteristics and speed ratio are variable and selectable by the operator.

As a result, speed ratio control of the torque converter 3 is performed. Further, the speed ratios of H, S, and T are controlled by the discharge@(swash plate angle) control of the variable displacement pump 5, and 9 is the pump swash plate angle control actuator. The discharge amount of the variable displacement pump 5 is controlled by the H, S, and T main circuit pressures.
As shown in the figure, the relational expression between the two is determined by a calculation unit 8 (described later).

7 is an H, S, and T main circuit relief valve, and the relief pressure of the H, S, and T147 circuits is continuously variable from a minimum value to a maximum value according to a command from the calculation unit 8.

10 indicates H, S, T main circuit pressure feedback.

Next, the calculation section 8 will be described.

(a) Determination of H, S, T variable pattern Type;
II, [1 signal from switching switch 12 and H, S, T
H, S, T by the signal from the power % switching dial 13
Determine the variable pattern (the relationship between the H, S, and T main circuit pressures and the pump swash plate angle).

(bl Pump discharge amount (swash plate angle) control Calculate the discharge amount (swash plate angle) from the variable pattern of H, S, T determined in (a) and HlS, T main circuit pressure, and control the pump swash plate angle. A drive signal for the actuator 9 is sent.

(cl Type I, U, m pattern (H, S, T
The main circuit pressure and pump swash plate angle relational expression) can be rewritten externally by a computer (see also Figure 3).
.

A flowchart of the system operation of the variable displacement transmission of the present invention described above is shown in FIG.

As described above, in the embodiment of the present invention, the torque converter and H, S, and T are arranged in parallel.

The H, S, and T speed ratios are controlled by the H, S, and T main circuit pressures, and the relationship between the H, S, and T speed ratios and the H, S, and T main circuit pressures can be arbitrarily selected. By actively controlling the H, S, and T sides, the overall characteristics of the running system can be made variable, thereby providing a variable capacity transmission that can arbitrarily control the capacities of the torque converter and the H, S, and T sides as a whole.

In other words, by making the capacity of the transmission variable, the engine output can be used effectively, and the driver of the vehicle can select the output performance of the transmission as desired, so it is possible to adjust the output performance of the transmission depending on the work conditions (size of the work site, specific gravity of the object, operator You can select the vehicle performance that matches your skills.

As an example of Type [~In, the relationship between the H, S, and T pump swash plate angles and main circuit pressure is shown as a linear function, but it should be noted that various functions (quadratic, higher order, discontinuous) can be adopted. Not even.

(Effect of the invention) This invention is constructed as described above in detail.

The H, S, and T speed ratios are controlled by the H, S, and T main circuit pressures, and the relationship between the H, S, and T speed ratios and the H, S, and T main circuit pressures can be arbitrarily selected. The capacity of the converter, H, S, and T as a whole can be controlled arbitrarily, and by making the capacity of the transmission variable, the degree of freedom in engine output distribution is increased, the engine output can be used effectively, and the engine can be made smaller. becomes possible. Furthermore, by making the capacity of the transmission variable, the driver of the vehicle can arbitrarily select the output performance of the transmission, so it is possible to select vehicle performance that is suitable for various work conditions.

In addition, unlike the conventional method, the capacities of H, S, and T are not increased (as a result, a variable capacity transmission with easy maneuverability and high durability can be obtained).

[Brief explanation of the drawing]

Fig. 1 schematically shows an outline of an embodiment of the present invention, Fig. 2 is a graph showing the relationship between pump discharge amount and H, S, and T main circuit pressure, and Fig. 3 is a graph showing the relationship between the pump discharge amount and the H, S, and T main circuit pressures. An explanatory diagram schematically showing each control, FIG. 4 is an operation flowchart of the system of the present invention, and FIG. 5(a)
, (b). (C1, (d) is a conventional device (al is a schematic diagram, (b) is a matching of the work equipment pump, torque converter, and engine, (
It is a graph which shows Cut vehicle performance, respectively. Figure 6 (
at, (bl, (cl is another conventional device, (a) is a schematic diagram, (b) and fc) are graphs showing the matching of the engine and torque converter and vehicle performance, respectively, Fig. 7 (al, (b) , (C) is yet another conventional device, (a) is a schematic diagram, and (b) and (C) are graphs of H, S, T control and vehicle performance. 1. Engine, 2. ... Transmission. 3... Torque converter, 4... H, S, T. 5... Variable displacement pump. 6... Fixed displacement hydraulic motor. 7... H, S, T main circuit relief Valve. 8... Calculation section. 9... Pump swash plate angle control actuator. 12... Type I, II, III changeover switch. 13... H, S, T power % changeover dial. Patent Applicant Komatsu Ltd. Agent (patent attorney) Osamu Matsuzawa T 1 Figure 2 Figure 5 (a) Figure 5 1 (b) Figure 5 (c) 17
Figure (Q) ka 7 Figure (C) Figure 7 (b) Procedure NeilF official text (way ヱ0 July 31, 1986)

Claims (1)

[Claims] A torque converter and a hydraulically driven transmission (H.S.T.) are arranged in parallel, the hydraulically driven transmission being formed by a variable displacement pump having a pump swash plate angle control actuator and a fixed displacement hydraulic motor; S. A T main circuit relief valve and a calculation section are provided, and the calculation section includes an accelerator pedal, Type I, II, III changeover switch, H. S. After receiving the signal from the T power % switching dial, the H. S. H. for the T main circuit relief valve and pump swash plate angle control actuator, respectively. S. A variable displacement transmission configured to send a T-main circuit relief pressure signal and a pump swashplate angle control signal.