JPH0143181B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a self-propelled working vehicle in which the vehicle speed is changed and controlled by a hydraulic clutch type transmission equipped with a plurality of hydraulic clutches whose operation is controlled by the directional control valves. The present invention relates to a hydraulic control device for controlling the hydraulic pressure applied to a corresponding hydraulic clutch when it is displaced to an operating position. The second invention of the present application is a hydraulic clutch type main transmission equipped with a plurality of hydraulic clutches whose operation is controlled by a directional control valve, and a sub-transmission connected in series to the main transmission. Relating to a hydraulic control device for controlling the hydraulic pressure applied to the corresponding hydraulic clutch when the directional control valve for the main transmission is displaced to each operating position in a self-propelled work vehicle that is controlled to change . BACKGROUND ART In a self-propelled work vehicle equipped with a hydraulic clutch type transmission, a directional control valve for switching and controlling the gears of the transmission is switched from a neutral position to one working position, or from one working position to another. It is well known that when the clutch is displaced to the operating position, the hydraulic clutch corresponding to the operating position after the displacement starts operating in a buffer manner, allowing the vehicle to start or shift smoothly, in order to improve the driver's feeling. As shown in FIG. 1, a hydraulic pressure gradually increasing type pressure regulating valve has been used in which the hydraulic pressure applied to a hydraulic clutch is gradually increased. Such pressure regulating valves are disclosed in, for example, Japanese Patent Publication No. 46-24924,
Special Publication No. 49-30049, Publication No. 57-18603, Publication No. 57-21051, Publication No. 2205-60,
Although it is disclosed in Utility Model Application Publication No. 60-45933, etc.
All conventional systems use a throttle to gradually increase the hydraulic pressure. For example,
Acted on a hydraulic clutch, e.g. 16
The tip of the oil pressure setting spring of the pressure regulating valve that sets the normal oil pressure of Kg/cm ² is received by a control piston that can move forward to the position where the spring load corresponding to the normal oil pressure is obtained, and the control piston is placed behind the control piston. In this structure, the hydraulic pressure of the oil supply circuit is applied to the hydraulic clutch via the throttle, and the control piston is gradually advanced by the hydraulic action via the throttle from the time of displacement of the directional control valve, thereby reducing the load on the hydraulic pressure setting spring. This is to gradually increase the clutch action oil pressure. Among the above-mentioned publications, the one in Japanese Patent Publication No. 60-2205 has another transmission connected in series with the hydraulic clutch type transmission, whereas In order to change the rising mode of the hydraulic pressure acting on the hydraulic clutch of a hydraulic clutch type transmission and to keep the starting or accelerating acceleration of the vehicle almost constant, the most retracted position of the control piston in the hydraulic pressure gradually increasing type pressure regulating valve is changed from that of other transmissions. A mechanism is provided for changing and controlling the disengagement hydraulic pressure for the hydraulic clutch by changing it in accordance with the active gear position. In addition, the one disclosed in Japanese Utility Model Application Publication No. 60-45933 inserts a solenoid valve that can selectively shut off the circuit in the circuit that applies the hydraulic pressure of the clutch oil supply circuit through a throttle behind the control piston in the hydraulic pressure gradually increasing type pressure regulating valve. At the same time, a circuit is provided that connects the back of the control piston to an oil tank, and another solenoid valve that can selectively shut off the piston is inserted and installed in this circuit, and the clutch action hydraulic pressure is controlled by displacement control of both solenoid valves. The rising mode can be changed in various ways. Problems and Problems to be Solved by the Invention Since such conventional clutches use a throttle to gradually increase the oil pressure, they have their own limitations in controlling the clutch action oil pressure. In other words, a throttle basically slows down the rise in oil pressure by delaying the oil flow, so conversely it does not allow a relatively rapid rise in oil pressure even if it is desired, and the degree of restriction also slows down the rise in oil pressure. Since the slope is uniquely determined, it is not possible to freely change and control the rising slope. In other words, if we look at this concretely, it is desirable to engage the hydraulic clutch in a buffering manner, but it is also possible to remove dirt or compost from the ground using a bucket or fork installed at the front or rear of the self-propelled work vehicle. When scooping up something, you have to move the vehicle in a dart-like manner to scoop it out properly, and when changing gears during heavy towing such as trenching or deep rotary work in the field, you have to change gears instantaneously. There is a risk that the vehicle may come to a halt, and furthermore, when escaping the vehicle itself or the work equipment towed by it from a wet field or muddy area, the vehicle must move forward in a dart-like manner. It is desirable or necessary to carry out a so-called shock shift, in which the clutch operating oil pressure is instantaneously raised to the normal oil pressure by a pressure regulating valve at the time of displacement, whereas in conventional gear shifting that utilizes a throttle, such a shock shift is approximately It's impossible. Furthermore, the way in which the hydraulic pressure rises to ensure a good feeling for the operator is different when the vehicle is being towed with heavy loads, when the vehicle is being towed with medium loads, and when the vehicle is under light loads such as driving on the road. The circumstances were such that a good feeling could not be guaranteed unless the construction was improved.
Similarly, depending on whether the vehicle is starting or changing gears, and between which two gears the gears are being shifted, in vehicles equipped with a hydraulic clutch type transmission and another transmission connected in series, the other transmission The rise of the clutch hydraulic pressure that guarantees good feeling varies depending on which gear position is in operation, whereas conventional systems have been designed to accommodate many such factors. It was difficult to control the hydraulic pressure. Furthermore, in recent years, solenoid valves have been widely used as directional control valves for hydraulic clutch type transmissions, and solenoid valves allow so-called jump shifting, that is, between 1st forward speed and 3rd forward speed, or between 1st forward speed and 1st reverse speed. This allows you to easily shift gears without passing through intermediate gears (neutral state when shifting between forward and reverse), but since such skip shifts change the vehicle speed significantly, it is difficult to shift. Despite the large size, hydraulic control to deal with it is difficult, and for this reason, in the conventional case, for example, when a jump shift operation is performed as disclosed in Japanese Patent Application Laid-Open No. 55-1229, an intermediate shift is performed. Shock has been alleviated by means that require a considerable amount of extra time to reach the desired vehicle speed, such as shifting to a new gear after a certain amount of time has elapsed. The next problem with using a throttle is that the rise characteristics of the oil pressure over time from the time of displacement of the directional control valve are largely influenced by the oil temperature and engine speed. In other words, the amount of oil that passes through the orifice that provides resistance to the flow of oil fluctuates greatly due to changes in oil viscosity due to oil temperature, and also changes in the amount of oil discharged from the pump due to changes in the hydraulic pump rotation speed based on changes in engine speed. The oil pressure rises rapidly when the oil temperature and engine speed are high, and the rise is slow when the oil temperature and engine speed are low. The rise characteristics of the oil pressure change over time as follows. Such characteristic fluctuations make it impossible to perform precise hydraulic control that always guarantees a constant good feeling to the driver when starting the vehicle and changing gears. Problems of the Invention Therefore, the present invention removes one restriction on hydraulic control by eliminating the throttle from the hydraulic control device for a hydraulic clutch type transmission, and then adopts a mechanism that enables precise control of clutch operating hydraulic pressure through feedback control. In addition, whether to start the vehicle or change gears,
A new hydraulic control device that achieves accurate hydraulic control in response to a variety of conditions, such as which two gears to shift between in a hydraulic clutch type transmission, and the size of the vehicle load. This is what we are trying to provide. Another object of the present invention is to install a hydraulic clutch type transmission device that can easily shift gears by operating a valve, since it is necessary to change the vehicle speed significantly depending on the type of work in self-propelled working vehicles such as agricultural vehicles. In consideration of the fact that transmissions are often used, which are connected in series with a mechanical (or in some cases hydraulic clutch type) sub-transmission to enable extremely multi-speed shifting, An object of the present invention is to provide a hydraulic control device that changes and controls the hydraulic control mode of a hydraulic clutch type main transmission device depending on which gear stage of the transmission device is activated. Technical Means for Solving the Problems As illustrated in FIGS. 2 and 3, the present invention includes a plurality of hydraulic clutches 2F ₁ , 2F ₂ , 2F ₃ , whose operation is controlled by directional control valves 1A and 1B. In a self-propelled work vehicle whose vehicle speed is controlled by a hydraulic clutch type transmission 3 equipped with 2R, the directional control valves 1A, 1
When B is displaced to each working position F ₁ , F ₂ , F ₃ , R, the corresponding hydraulic clutches 2F ₁ , 2F ₂ , 2F ₃ ,
The present invention relates to a hydraulic control device for controlling hydraulic pressure applied to 2R. In the illustrated example, the other transmission 4
is connected in series with a hydraulic clutch type transmission 3, the hydraulic clutch type transmission having a reverse 1st speed R is connected to the main transmission 3, and the other mechanical type transmission is connected to the auxiliary transmission 4. has been done. In the hydraulic control device for the above-mentioned purpose, the present invention first includes a hydraulic clutch 2F ₁ as illustrated in FIG.
-2R, the tip of the oil pressure setting spring 6 of the pressure regulating valve 5 that sets the normal oil pressure applied to the
A control piston 8 that can move forward to a position where a spring load corresponding to the normal oil pressure is obtained (a position where it abuts the annular step 7 on the inner surface of the valve case) receives the spring load, and a hydraulic clutch 2 is installed behind the control piston 8.
A first circuit 10 that guides the oil pressure of the oil supply circuit 9 for F ₁ -2R without going through a throttle, and a second circuit 12 that connects the back of the control piston 8 to an oil tank 11 are provided. A first solenoid valve 13A and a second solenoid valve 13B each having a position for making each circuit conductive and a position for cutting off the circuit are inserted into the circuit 10 and the second circuit 12, respectively. Each solenoid valve 13A, 13B has a solenoid 14A,
The position is changed by excitation magnetization of 14B (hereinafter, excitation is referred to as "on" and demagnetization is referred to as "off").
The solenoid valve 13A is configured to conduct the first circuit 10 when the solenoid 14A is turned off, and the second solenoid valve 13B is configured to cut off the second circuit 12 when the solenoid 14B is turned off. ing. As usual, the pressure regulating valve 5 includes a valve body 17 that sets the hydraulic pressure corresponding to the load of the spring 6 while relieving oil from the pump port 15 to the tank port 16 under the force of the hydraulic pressure setting spring 6. There is. The pump port 15 is connected to the oil supply circuit 9, and an oil passage hole 17a is formed behind the valve body 17 in the valve body 17 for guiding the hydraulic pressure of the pump port 15. Next, this invention, as illustrated in FIGS. 1 and 4,
A switching valve operation detection means 18 detects a displacement operation between two positions of the directional switching valves 1A and 1B, and a plurality of load conditions are selectively and artificially set depending on the magnitude of the vehicle load. Hydraulic control mode setting means 19 outputs a signal corresponding to the loaded load state.
and a hydraulic pressure sensor 20 for detecting the hydraulic pressure of the oil supply circuit 9. In the examples shown in FIGS. 1 and 4, according to the second aspect of the invention, a sub-gear detecting means 21 is further provided for detecting the gear position in the operating state in the sub-transmission device 4. The electronic control mechanism of the present invention includes a hydraulic control information storage means 22, a valve operation determination means 23, an address designation means 24, a control oil pressure setting means 25, a timer means 26, a comparison means 27, and an electronic control mechanism as illustrated in FIG. A hydraulic control signal generating means 28 is provided. Among these, the hydraulic control information storage means 22 stores hydraulic control information corresponding to the displacement between the two positions of the directional control valves 1A, 1B and the magnitude of the vehicle load, and stores the control hydraulic pressure lower than the normal hydraulic pressure and the control hydraulic pressure. The control time for which the oil pressure should be maintained is stored in an address corresponding to each control oil pressure and an address corresponding to each control time, and when a series of addresses is specified, the control oil pressure stored in the series of addresses is sequentially stored. The signal corresponding to the control time and the signal corresponding to the control time can be output in this order. That is, the present invention extracts a suitable series of data from the data group stored in the hydraulic control information storage means 22 each time the directional control valves 1A, 1B are displaced, and performs hydraulic control accordingly. For example, the hydraulic control characteristics shown in FIGS. 5a and 5b are obtained. FIG. 5a shows an example when the vehicle starts, and when the directional control valves 1A and 1B are moved from the neutral position N to the one-acting position, a certain low oil pressure _P1 is maintained for a time _T1 , and then The normal oil pressure Pa is obtained by holding the slightly higher low oil pressure _P2 for a time _T2 . Further, FIG. 5b is an example of a gear change, and the directional control valve 1
When A and 1B are moved from one working position to another working position, the normal oil pressure Pa that had been established in the oil supply circuit 9 is rapidly lowered to the low oil pressure _P'1 , and the low oil pressure P' ₁ for a time T′ ₁ , and then
I'm getting Pa. The combination of such control oil pressure and control time is a series of data, and the series of addresses corresponding to the oil pressure control illustrated in FIGS. 5a and 5b are shown in Table 1 and Table 2 below, respectively.

【table】

[Table] To give a specific numerical example, in Table 1, the series of addresses m ₀ - m ₃ corresponds to the position of the directional control valves 1A and 1B from the neutral position N to the forward 1st speed position when the vehicle is under a light load state.
If it is selected and specified when it is displaced to F ₁ , for example, P ₁ = 3.00Kg/cm ² ,
T ₁ = 750msec, P ₂ = 5.01Kg/cm ² , T ₂ = 750msec
, and in Table 2 a series of addresses
m ₀ ′ and m ₁ ′ are directional control valve 1 when the vehicle is under medium load.
A, 1B from forward 2nd gear position F ₂ to forward 3rd gear position F ₃
For example, P ₁ ′ = 5.03Kg/cm ² , T ₁ ′ = 830msec.
It is. Next, the switching valve operation determining means 23 receives a signal input from the switching valve operation detecting means 18 and determines between which two positions the directional switching valves 1A, 1B are operated. In other words, in the illustrated example, the directional control valves 1A and 1B are in the neutral position N and the forward third speed position.
A hydraulic pump 29 connects the front side solenoid valve 1A with F ₃ , reverse 1st speed position R and the rear side solenoid valve 1B with neutral position N, forward 1st speed position F ₁ , and forward 2nd speed position F ₂ . The solenoid valves 30F ₁ , 30F ₂ , 30F ₃ ,
When operating the switching valves by energizing the switching valve 30R, the pre-operation signal from the switching valve operation detection means 18 is memorized and the longitudinal position of the directional switching valves 1A, 1B is calculated from this and the post-operation signal. It is assumed that the determination is made and a corresponding signal is output. Further, in the first invention in which the above-described auxiliary gear stage detection means 21 is not provided, the address designation means 24 receives signal input from the switching valve operation determination means 23 and the hydraulic control mode setting means 19;
In the second aspect of the invention, which includes the auxiliary gear position detecting means 21, the switching valve operation determining means 23, the auxiliary gear position detecting means 21, and the hydraulic control mode setting means 19 are configured to receive signal inputs, respectively. A series of addresses are calculated and selected according to the signal, and the series of addresses is specified to the hydraulic control information storage means 22, and the first address of the series of addresses (address m ₀ in Table 1, address in Table 2)
It is assumed that a signal corresponding to the control oil pressure stored in the address corresponding to m ₀ ′ is output. Next, as similarly illustrated in FIG. 1, the control oil pressure setting means 25 receives a control oil pressure signal from the oil pressure control information storage means 22, sets the control oil pressure, and upon completion of the setting, the oil pressure control information storage means 22
It is assumed that an address increment signal is given to the
Further, the timer means 26 receives a control time signal from the hydraulic control information storage means 22, sets the control time, and gives an address increment signal to the hydraulic control information storage means 22 as the control time elapses. Ru. The comparison means 27 is operated upon receiving a signal input from the timer means 26, compares the output signal of the control oil pressure setting means 25 with the output signal of the oil pressure sensor 20, and outputs a feedback control signal according to the magnitude thereof. Further, the hydraulic control signal generating means 28 receives the feedback control signal from the comparing means 27 and performs the above-mentioned first signal.
By selectively displacing the solenoid valve 13A and the second solenoid valve 13B, a signal for feedback control of the oil pressure set by the pressure regulating valve 5 is output. Operation Therefore, according to the present invention, the directional control valve 1
When A, 1B is displaced to each working position F ₁ , F ₂ , F ₃ or R, the corresponding hydraulic clutches 2F ₁ , 2F ₂ ,
The hydraulic pressure applied to 2F ₃ or 2R is controlled as follows. That is, first, when the directional control valves 1A and 1B are moved to either operating position and the oil drain from the oil supply circuit 9 disappears, as shown in FIG.
Oil is supplied behind the control piston 8 via the first circuit 10, which moves the control piston 8 forward and increases the load on the oil pressure setting spring 6. Further, as shown in FIG. 6, the solenoid 14A is turned on, the first solenoid valve 13A shuts off the first circuit 10, and the
4B and the second solenoid valve 13B makes the second circuit 12 conductive, oil is drained from behind the control piston 8, and the control piston 8 is moved from the most retracted position shown in FIG. If it were moving forward, the piston 8 would be moved backward by the force of the oil pressure setting spring 6, thereby reducing the load on the spring 6. Furthermore, as shown in FIG.
If A is turned on and the first circuit 10 is cut off by the first solenoid valve 13A, and the solenoid 14B is turned off, the back of the control piston 8 is blocked by both the solenoid valves 13A and 13B, and the control piston 8 is kept constant. The load on the oil pressure setting spring 6 is kept constant. Therefore, in order to obtain the hydraulic control as exemplified in FIG.
1st stage control oil pressure P ₁ at position 3A, 13B
When the control piston 8 moves forward to a position where , the solenoid valves 13A and 13B are moved to the position shown in _FIG .
Next, the solenoid valves 13A and 13B are again set to the positions shown in FIG. 2, and the control piston 8 is advanced to the position where the second stage control oil pressure _P2 is obtained. The control piston 8 is moved to the position shown in FIG. 7 and kept at the same position for a time T ₂ , and then both the solenoid valves 13A and 13B are moved to the position shown in FIG. 2 and kept at the same position. This can be achieved by performing the relief operation of the pressure regulating valve 5 at the normal oil pressure Pa at this position. Furthermore, in order to obtain the hydraulic control as illustrated in FIG. 6 to the position shown in Figure 6, and the oil pressure P of the oil supply circuit 9 is changed to the control oil pressure.
After rapidly decreasing to P ₁ ′, both solenoid valves 13
A, 12B are moved to the position shown in _FIG .
This can be achieved by moving A and 13B to the positions shown in FIG. 2 and keeping them at the same positions to allow the pressure regulating valve 5 to continue its relief operation at the normal oil pressure Pa. Next, when the directional control valves 1A and 1B are displaced to their respective operating positions, a series of addresses designated by the action of the address designating means 24 from among the address group storing the data group in the hydraulic control information storage means 22 (the The addresses m ₀ , m ₁ , m ₂ , m ₃ in Table 1 and the addresses m' ₀ , m' ₁ in Table 2 are for directional control valve 1.
What two positions A and 1B were displaced between (for example, displacement from neutral position N to 1st forward speed position, displacement from 1st forward speed position _F1 to 2nd forward speed position _F2, etc.) and the conditions. and the control oil pressure and control time adapted to the conditions such as the current vehicle load condition (for example, medium load condition or light load condition) set by the hydraulic control mode setting means 19. Become what you are. In the second aspect of the invention, a series of addresses are further stored in which the control oil pressure and control time are adapted to the operating gear position (for example, 1st speed or 2nd speed) of the auxiliary transmission 4 as other conditions. When a series of addresses in the oil pressure control information storage means 22 are specified by the address specifying means 24 and a signal corresponding to the control oil pressure stored in the first address is output, the control oil pressure setting means 25 sets the control oil pressure. The series of addresses in the hydraulic control information storage means 22 are then incremented, and a signal corresponding to the control time stored in the next address is output. Based on this output signal, the timer means 26 sets the control time and then outputs a signal for operating the comparison means 27. In the illustrated example, the timer means 26 is provided with a loop counter as described later. The comparison means 27, which operates for the control time set by the timer means 26, compares the control oil pressure set by the control oil pressure setting means 25 with the oil pressure sensor 2.
Compares the oil pressure of the oil supply circuit 9 detected by 0 and outputs a feedback control signal according to the magnitude thereof,
The hydraulic control signal generating means 28 outputs a signal for turning on and off the solenoids 14A and 14B (FIGS. 2, 6, and 7) shown as the hydraulic control solenoid group 14 in FIG. This causes the first and second solenoid valves 13A, 13B to
selectively displaced between the position shown in the figure, the position shown in FIG. 6, and the position shown in FIG. 7;
Feedback control is achieved in which the oil pressure in the oil supply circuit 9 is maintained at the control oil pressure set by the control oil pressure setting means 25 for the control time set by the timer means 26. When performing one-stage control using only one type of control oil pressure as shown in FIG. Both solenoid valves 13A,
13B assumes the position shown in FIG. 2, and the control piston 8 is fully advanced, the pressure regulating valve 5 performs a relief operation to reduce the oil pressure in the oil supply circuit 9 and, therefore, the action of the directional control valves 1A and 1B after displacement. The hydraulic pressure applied to the hydraulic clutch corresponding to the position becomes the normal hydraulic pressure Pa, and the same hydraulic pressure Pa is maintained. When performing two-stage control using two types of control oil pressure as shown in FIG. 5a and Table 1 above, the timer means 2
The control oil pressure corresponding to the control oil pressure stored in the third stage address of a series of addresses specified in the oil pressure control information storage means 22 by the address increment signal outputted by 6 as the control time elapses. After the signal is output, the second stage control oil pressure is held for the selected control time, the normal oil pressure Pa is obtained, and the same oil pressure Pa is maintained as described above.
is maintained. The hydraulic clutch corresponding to the operating position of the directional control valves 1A and 1B after displacement is set to the normal hydraulic pressure as described above.
By applying a control hydraulic pressure lower than Pa for a certain period of time, initial engagement is completed during that time and operation starts without a shock. As shown in Fig. 2, no throttle is provided in the hydraulic circuit, and the clutch action hydraulic pressure is controlled by on/off control of the two electromagnetic valves 13A and 13B, so the rise characteristic of the hydraulic pressure can be adjusted quickly or slowly. Therefore, the hydraulic pressure control information data group stored in advance in the hydraulic control information storage means 22 can be configured to obtain hydraulic pressure rise characteristics that best suit each of various conditions. Then, from among such data groups, a series of data (control oil pressure data and control time data) suitable for each condition is selected, and hydraulic pressure control according to the same series of data is performed using the set control oil pressure and oil pressure. Since feedback control is performed while comparing and contrasting the actual oil pressure detected by the sensor 20, control that faithfully follows the series of data described above can be achieved. Embodiment Transmission Structure FIG. 3 shows the transmission of a self-propelled working vehicle equipped with an embodiment of the present invention, with the transmission portion of the working machine drive system omitted. In FIG. 3, numeral 31 is an engine, and the hydraulic clutch type main transmission 3 has a main clutch 32 and a hydraulic pump 2 for this engine 31.
9 and a power shift shaft 34 parallel to the drive shaft 33 connected thereto.
Further, the sub-transmission device 4 is disposed between a hollow transmission shaft 37 connected to the power shift shaft 34 for deceleration through gears 35 and 36, and a transmission shaft 38 parallel thereto. The transmission shaft 38 is configured to transmit output to a differential device 39, and the left and right output shafts of the differential device 39 are connected to the left and right rear wheels 4 via a final reduction gear mechanism 40.
connected to 1. The main transmission 3 has a 4 fixedly installed on the drive shaft 33.
The four gears 42F ₁ , 42F ₂ , 42F ₃ , 42R and the four gears 4 loosely fitted on the power shift shaft 34
The corresponding gears 3F ₁ , 43F ₂ , 43F ₃ , and 43R are meshed with each other through the intermediate gear 44 for the gears 42R and 43R for reverse gear, and the gear 43F ₁ on the power shift shaft 34 - said hydraulic clutches 2F ₁ , 2F ₂ arranged at 43R for selectively coupling said gears to the power shift shaft 34;
2F ₃ and 2R are provided. As mentioned above, this main transmission 3 has forward 1,
It has four speeds: 2nd and 3rd speeds and 1st reverse speed. The sub-transmission device 4 has three gears 45 on the transmission shaft 37.
, 45, 45 are fixedly set, and a gear 46 meshed with the gears 45, 45 among them.
, 46 are loosely fitted onto the speed change shaft 38, and a shift gear 46 which can mesh with the gear 45 is provided on the speed change shaft 38 between the two gears 46, 46 so as to be slidable only. A dog clutch is provided between the shift gear 46 and each of the gears 46, 46, which is engaged by shifting the shift gear 46, and the sub-transmission device 4 selectively shifts the shift gear 46 to operate the gears 45, 46. By operating the gears 45 and 46, transmission is performed in 1st speed; by operating gears 45 and 46, transmission is performed in 2nd speed; and by applying gears 45 and 46, transmission is performed in 3rd speed. Valves and hydraulic circuits Valves 1A, 1 provided in the illustrated embodiment
B, 5, 13A, and 13B are as described above with respect to FIG. Overview of Control Mechanism The components 23-28 of the electronic control mechanism described above with reference to FIG. 1 are the one-chip microcomputer (abbreviated as "microcomputer") shown in FIG.
It is built into 48. As shown in FIG. 1, the solenoid 30 of the directional control valves 1A and 1B, which is shown as the main shift control solenoid group 30 in the same figure,
A main shift selection signal generating means 49 is provided for outputting a signal for selectively turning on F ₁ , 30F ₂ , 30F ₃ , and 30R (Fig. 2). In the example shown in FIG. 1, the switching valve operation determining means 23 is operated by a signal outputted at the same time as the signal outputted to the addressing means 24. Further, the switching valve operation determination means 23 is reset by the timer means 2.
6 is performed by a reset signal output upon completion of setting the control time. The above-mentioned main shift selection signal generating means 49 is also built into the microcomputer 48. As usual, the microcomputer 48 basically
It is composed of a CPU 50, a RAM 51, and a ROM 52, and programs necessary for controlling the CPU 50 are written in the ROM 52. According to this program, the CPU 50 takes in necessary external data from the input port 53, performs arithmetic processing while exchanging data with the RAM 51, and sends the processed data as necessary to the output port. 54. Similarly, as shown in FIG. 4, the switching valve operation detection means 18, hydraulic control mode setting means 19, oil pressure sensor 20, and sub-gear detection means 21 described above in connection with FIG.
It is connected to 3. The output port 54 of the microcomputer 48 has switching transistors TRa and TRb (transistor TRb
(shown in FIG. 10) and the solenoid 30 of the directional control valves 1A and 1B described above when turned on
Switching transistors TR ₁ , TR ₂ , TR ₃ , TR 4 that turn on F ₁ , 30F ₂ , 30F ₃ , _30R
(Transistors TR ₂ , TR ₃ , and TR ₄ are not shown)
are also connected at each base. Which mode is set by the main shift display section 55, which displays whether the main transmission 3 is in a neutral state or which gear stage is in operation, and the hydraulic control mode setting means 19? A display panel 57 is provided which includes a mode display section 56 for displaying the mode display section 56 and a mode display section 56 for displaying the mode display section 56.
Both display sections 55 and 56 are connected to the output port 54, with the display section 56 having a function of processing data to be displayed. Mechanism external to the microcomputer The switching valve operation detection means 18, hydraulic control mode setting means 19, oil pressure sensor 20, and sub-gear detection means 2 provided outside the microcomputer 48
The specific structure of No. 1 will be explained. First _, the switching _valve operation detection means 18, as shown in _FIG . 5 touch switches 59N to be operated,
59F ₁ , 59F ₂ , 59F ₃ , and 59R are inserted into five separate parallel circuits that ground the power supply circuit through pull-up resistors, and the parallel circuits are separately connected to the input port 53 of the microcomputer 48. The information is stored in the RAM when each switch is turned on momentarily (about 10msec).
By updating and storing it to 51,
Directional switching valve 1A, 1 from front and rear switch operation information
The displacement operation between each two positions of B is detected. Next, the hydraulic control mode setting means 19 similarly controls the fourth hydraulic control mode setting means 19.
As shown in the figure, a touch switch 60H is used to set the heavy load (heavy traction) state of the vehicle, a touch switch 60M is used to set the medium load state, and a touch switch 6 is used to set the vehicle to a light load state.
Three touch switches 60H, 60 consisting of 0S
M, 60S are inserted into three separate parallel circuits that ground the power supply circuit through pull-up resistors, and the parallel circuits are each connected to the input port 53 of the microcomputer 48. ,
When any one switch is instantaneously turned on, that information is input to the RAM 51 and stored. How the load state and the hydraulic control mode are related will be described later. Moreover, the oil pressure sensor 20 is as shown in FIG.
Four strain gauges Rg ₁ , Rg ₂ , Rg ₃ , Rg are provided on a diaphragm 62 that is screwed onto a sensor mounting portion 61 provided in the oil supply circuit 9 (FIG. 2) and receives the oil pressure of the oil supply circuit 9. ₄ is attached to detect the oil pressure of the oil supply circuit 9 from changes in the resistance values of the strain gauges Rg ₁ -Rg ₄ based on changes in oil pressure. The four strain gauges are incorporated into a bridge circuit as shown in Figure 4, and the amplifier 6
3 and the A/D converter 64, the microcomputer 48
is connected to the input port 53 of. Next, the auxiliary gear stage detection means 21, as shown in FIG.
5. These sensor switches 6
5, 65, 65 are shift forks 66 for shifting the shift gear 46 shown in FIG.
When the fork shaft 67 and the shift fork 66 are operated by the auxiliary shift lever 68 to a position where the shift gear 46 is shifted to each of the above-mentioned shift operating positions, It is said that it can be turned on selectively. That is, the forkshaft 67 has four slots 70N, 70, 7 into which the detent balls 69 enter when the shift gear 46 is in the neutral position and in each shift action position.
0 and 70 are formed on the lower surface side, and when the shift gear 46 is in each gear change operation position, a corresponding sensor switch 65, 65 or 65 is formed.
One slot 71 into which a movable contact enters is formed on the top surface side, and each sensor switch 65, 65
, 65 is turned on when its movable contact moves into the slot 71. These sensor switches 65, 65, and 65, which detect the first, second, and third gears of the sub-transmission device 4 by turning on, are connected to each other, which ground the power supply circuit through a resistor, as shown in FIG. It is inserted into three other parallel circuits, each of which is connected to the input port 53 of the microcomputer 48, and one of the sensor switches 65, 6 is inserted.
5 or 65 is in the ON state, the gear position in the operating state in the sub-transmission device 4 is detected. Electronic Control Mechanism The specific structure of the electronic control mechanism described above with reference to FIG. 1 will be explained with reference to FIG. 10, which shows its main parts as an analog equivalent circuit. The control oil pressure setting means 25 illustrated in FIG. In the equivalent circuit shown, 73A and 73B indicate first and second comparators that respectively set the lower and upper limits of the control oil pressure. The oil pressure sensor 20 is connected to each comparator 73A, 73B via the amplifier 63.
is connected to the negative input terminal of the A power supply circuit is connected to the positive input terminal of the first comparator 73A, and a group of parallel resistors R ₁ a, R ₂ a
…, connected via Rna, each resistor R ₁ a,
Normally open relay switches S ₁ a, S ₂ a..., Sna are connected in series with R ₂ a..., Rna, and the relay switches S ₁ a, S ₂ a..., Sna are selectively turned on. After the power supply voltage Vcc is appropriately dropped by any one of the resistors _R1a , _R2a ..., Rna, the first comparator 7
It is assumed that 3A is applied to the positive side input terminal. Similarly, a power supply circuit is connected to the positive input terminal of the second comparator 73B, and a group of parallel resistors R ₁ b, R ₂ b..., Rnb and a group of normally open relay switches S ₁ b connected in series thereto are connected to a power supply circuit. , S ₂ b…, Snb and relay switch S ₁ b,
By selectively turning on S ₂ b…, Snb, the power supply voltage Vcc
is appropriately dropped by any one of the resistors R ₁ b, R ₂ b..., Rnb, and then the second comparator 73B
It is assumed that the voltage is applied to the positive input terminal of the Resistors R ₁ a, R ₂ a…, Rna and resistors R ₁ b, R ₂ b…
Rnb is a pair of resistors with the same number, and of the two resistors in the pair, the one with the symbol a has a resistance value that is higher by an appropriate value than the one with the symbol b. It is said that Also, relay switches S ₁ a, S ₂ a..., Sna and relay switches S ₁ b,
S ₂ b,...Snb are assumed to have the same number attached as a pair and turn on in conjunction with each other. Therefore, any pair of relay switches Sia,
When Sib is turned on, each comparator 73A, 73 is connected via the corresponding resistor Ria, Rib.
The voltage applied to the positive input terminal of B is slightly higher at the second comparator 73B. resistance
R ₁ a, R ₂ a..., Rna and resistances R ₁ b, R ₂ b..., Rnb are for setting the control oil pressure as described above, and now the paired resistances Ria and Rib are the control oil pressure Pi. If it is used to set the control oil pressure Pi, the first and second comparators 73A and 73
B is the lower limit oil pressure of the control oil pressure as shown in Figure 11.
Pimin and upper limit oil pressure Pimax will be set. And these comparators 73A, 73B
Considering that the voltage signal corresponding to the oil pressure of the oil supply circuit 9 detected by the oil pressure sensor 20 is input to the negative input terminal of the first comparator 73A.
is turned on and outputs an H level signal Sgu when the oil pressure of the oil supply circuit 9 is higher than the lower limit oil pressure Pimin, and the second comparator 73B
When the oil pressure is higher than the upper limit oil pressure Pimax, it turns on and outputs an H level signal Sgy. In other words, resistance R ₁ a, R ₁ b, R ₂ a, R ₂ b…, Rna,
Rnb corresponds to the control oil pressure data to be stored in the oil pressure control information storage means 22, and the control oil pressure setting means 25 corresponds to the comparators 73A and 73B and receives the control oil pressure signal output from the oil pressure control information storage means 22, and each control oil pressure A hydraulic pressure setting table corresponding to FIG. 11 is created by setting the upper and lower limits of A signal is output to bring the oil pressure in the oil supply circuit 9 within the upper and lower limits of the control oil pressure. Next, the equivalent circuit of FIG. 10 is provided with a monostable multivibrator 74 constituting a timer means, and the trigger signal input terminal of this multivibrator 74 is connected to two parallel switches SW ₁ ,
Connected to the power circuit via SW ₂ . Also, among the resistors and capacitors C for determining the time width of the voltage pulse generated when the multivibrator 74 is triggered, the resistors are a group of resistors R ₁ c, R ₂ c..., connected in parallel with each other. Rnc, and each resistor R ₁ c, R ₂ c..., Rnc is connected to the power supply circuit via a normally open relay switch S ₁ c, S ₂ c..., Snc. Then, the first comparator 73A and the multivibrator 74 receive the respective output signals.
AND gate 75A and second comparator 73B
and a second AND gate 75B to which each output signal of the multivibrator 74 is input, and the output terminal of the second AND gate 75B is connected to the base of the transistor TRb for selectively turning on the solenoid 14B. connected to.
In addition, there is another gate on the secondary side of the first AND gate 75B.
AND gates 76 are provided.
First AND gate 75A for AND gate 76
and the second AND gate 75B,
The output signal of the second AND gate 75B is inverted by an inverter 77 and then inputted, and the output terminal of the AND gate 76 is connected to the base of the transistor TRa for selectively turning on the solenoid 14A. are doing. So now, a group of relay switches S ₁ c, S ₂ c
Consider the case where the multivibrator 74 is triggered and the voltage pulse signal Sgi is output when one of the relay switches Sic of the Snc is on and the corresponding resistor Ric is under action. As you can see, the oil pressure in the oil supply circuit 9 is lower than the lower limit oil pressure Pimin shown in FIG.
If both 3A and 73B are turned off and the signals Sgu and Sgv are not output, each output terminal of the first and second AND gates 75A and 75B is at the L level, and therefore the output of the AND gate 76 is Both transistors TRa and TRb are also at L level.
are both off, and the first and second solenoid valves 13
A and 13B are held in the positions shown in FIG. Further, if the oil pressure of the oil supply circuit 9 is in the range between the upper and lower oil pressure limits Pimax and Pimin shown in FIG. 11 and only the first comparator 73A is turned on and outputs the signal Sgu, then the first AND gate The output terminal of 75A becomes H level, and the second
Since the output terminal of the AND gate 75B is at the L level and the secondary side of the inverter 77 is at the H level, the output terminal of the AND gate 76 is at the H level and the transistor TRa is turned on. Valve 13A is displaced to a position where circuit 10 is cut off, and both electromagnetic valves 13A, 13
The position of B is as shown in FIG. Next, the oil pressure of the oil supply circuit 9 is set to the upper limit oil pressure shown in FIG.
First and second comparator 7 higher than Pimax
If both 3A and 73B output signals Sgu and Sgv, the first and second AND gates 7
Since the output terminals of 5A and 75B both go to H level, the secondary side of inverter 77 goes to L level, which turns off AND gate 76, and only transistor TRb, which receives the base signal from second AND gate 75B, turns off. When turned on, the second solenoid valve 13B is displaced to a position where the circuit 12 is brought into conduction, and the positions of both solenoid valves 13A and 13B are as shown in FIG. The reason why both electromagnetic valves 13A and 13B are changed from the position shown in FIG. 2 to the position shown in FIG. 6 or 7 as described above is when the multivibrator 74 outputs the pulse signal Sgi. only between
The time width of the same signal Sgi is a group of resistors R ₁ c, R ₂ c...,
It changes depending on which Rnc is activated. Also, the first and second solenoid valves 13A, 1
By changing the position of 3B according to the oil pressure of the oil supply circuit 9 in the above-described manner, the oil pressure control as illustrated in FIG. become. That is, the resistors R ₁ c, R ₂ c..., Rnc correspond to the control time data stored in the oil pressure control information storage means 22, and the switch SW is activated by a signal corresponding to the aforementioned address increment signal outputted by the control oil pressure setting means 25. ₁
In addition, when performing two-stage hydraulic control as illustrated in Fig. 5a, further turn switch SW ₂ once.
By turning it on, the relay switch SIC
The control time selected in the timer means 26
It will be set and output to the corresponding multivibrator 74. Timer means 2 shown in FIG.
Reference numeral 6 is a loop counter that is involved in digital control within the microcomputer 48 and sets the set time as a count value by inputting a signal from the hydraulic control information storage means 22, and is connected to the comparison means 27 and the hydraulic control signal generation means 28. The device is equipped with a loop counter that forms a loop between the two and is reset when a set time elapses. Hydraulic control signal generation means 2
8 outputs signals corresponding to AND gates 75B and 76 in the equivalent circuit of FIG. In the equivalent circuit of Fig. 10, AND gate 7
The output terminal of 6,75B is connected to transistors TRa and TRb.
There is an operating tool 78 in the circuit connected to the base of the
A switch that can be selectively turned off by human operation.
SWa and SWb are inserted. Therefore, if these switches SWa and SWb are operated, both transistors TRa and TRb are turned off under any condition, and the first and second solenoid valves 13A and 13B take the positions shown in FIG. 2. . When the operating tool 78 is operated to displace the directional control valves 1A, 1B from the neutral position N to any operating position, the oil pressure P of the oil supply circuit 9 changes as shown in FIG. 12a. As a result, the hydraulic pressure applied to the hydraulic clutches corresponding to the positions of the switching valves 1A and 1B is rapidly increased to the normal hydraulic pressure Pa. Furthermore, when a similar operation is performed to move the directional control valves 1A, 1B from one working position to another, the switching valves 1A, 1B pass through the neutral position N, as illustrated in FIG. 12b. Although a slight drop in oil pressure occurs due to the displacement, the clutch working oil pressure P is substantially equal to the normal oil pressure Pa.
will remain maintained. A corresponding configuration is adopted in the electronic control mechanism shown in FIG.
When the heavy load state of the vehicle is set by the touch switch 60H (FIG. 4), the address designating means 24 recognizes the same heavy load state and sends it to the switching valve operation determining means 23 instead of to the hydraulic control information storage means 22. In this case, the first and second solenoid valves 13A, 13B are kept at the positions shown in FIG. 2 and the position shown in FIG. Hydraulic control is performed as illustrated. In the microcomputer 48 shown in FIG. 4, the control oil pressure data group and the control time data group are written in the ROM 52, and the necessary control programs are also written.
It is written in ROM52. Directional switching valve 1
A series of data required for each displacement operation of A and 1B is taken out from the ROM 52 by the CPU 50, temporarily stored in the RAM 51, and processed by the CPU 50 as required. Control Oil Pressure and Control Time The control oil pressure data and control time data stored in the oil pressure control information storage means 22 will be explained. As described above, this invention attempts to perform oil pressure control in accordance with control oil pressure and control time data stored in a series of addresses selected and specified by the address specifying means 24 in accordance with various conditions each time. In the illustrated example, the main transmission 3 is on the forward side 3.
It is equipped with a total of four gear stages, one on the reverse side and one on the reverse side, and correspondingly, the directional control valves 1A and 1B are in the neutral position N.
and 4 operating positions F ₁ , F ₂ , F ₃ , and R. Therefore, it does not matter from which position to which position the directional control valves 1A and 1B are displaced. The conditions are as follows: switching valve 1A, 1
Considering the position before and after B, mark ○ and △ in the following table 3.
There are 20 ways shown by the marks.

[Table] In Table 3, the displacement operations marked with △ are operations that return the directional control valves 1A and 1B to the neutral position N to stop the vehicle, so no hydraulic control is required. There are 16 hydraulic control conditions marked with ○. In addition, in the illustrated example, the auxiliary transmission 4 has three gear stages, and the conditions change depending on which gear the auxiliary transmission 4 is placed in. Therefore, the main transmission 3 and the auxiliary transmission 4 Considering these together, there are 48 conditions (16 x 3 = 48). Further, in the illustrated example, three types of vehicle load conditions can be set by the hydraulic control mode setting means 19, and when these conditions are considered together, there are 144 conditions (48×3=144). However, in the mechanism shown in FIG. 1, when the heavy load state of the vehicle is set, the hydraulic control information stored in the hydraulic control information storage means 22 is not used and both the solenoid valves 13A and 13B are activated. Since it is kept in the position shown in Figure 2, there is no need to store data under heavy load conditions, and in the end, hydraulic control information tailored to 96 conditions (48 x 2 = 96) can be stored. This will be stored in the hydraulic control information storage means 22. In other words, there are 96 consecutive addresses designated by the address designating means 24. Next, I will explain the principles of how hydraulic control should be done in order to improve the driver's feeling and quickly reach the desired vehicle speed depending on various conditions. In some cases, due to the inertia of the vehicle, it is necessary to set the control oil pressure and control time to be higher and longer at the time of starting, as shown in Figure 5a above. It is desirable to perform two-stage control as shown above. Furthermore, since the operator is more likely to feel a shock when starting the vehicle backwards, it is necessary to make the control time longer than when starting the vehicle forwards. When performing a jump shift without going through an intermediate gear, two-stage control is generally appropriate because the shock is large, and this is especially true for shifting from a forward gear to a reverse gear. However, in such two-stage control, in order to quickly obtain the desired vehicle speed, the control oil pressure should be as high as possible and the control time should be as short as possible within a limit that does not impair the driver's feeling. By increasing the control oil pressure and shortening the control time, slippage of the hydraulic clutch is also reduced, and wear of the friction elements and rise in oil temperature are suppressed. Next, in relation to vehicle speed, the driver's shock is greater when shifting between low vehicle speeds, and if the control oil pressure is too low when shifting between high vehicle speeds, the hydraulic clutch is likely to slip and the vehicle will There are circumstances in which the clutch slip causes the vehicle to slow down or stop for a long time, causing poor feeling for the driver.
It is necessary to determine the control oil pressure and control time in correspondence. In relation to the vehicle load, the shock is greater when starting and shifting when the load is small, so the control oil pressure and control time are determined in consideration of this point. The optimal hydraulic control mode for various conditions can be determined based on the above-mentioned principles and actual tests, but some specific examples are as follows. FIGS. 13a and 13b illustrate the manner of hydraulic control performed during starting and shifting when the sub-transmission device 4 is in a relatively high speed gear or the vehicle load is relatively large. When starting in Figure 13a, the first stage control hydraulic pressure is controlled higher to reduce clutch slip when starting in third forward speed _F3 compared to starting in first forward _speed F1. In addition to making the time shorter, the second stage control requires three forward speeds.
Since starting at _F3 requires more energy and speeds up the completion of clutch engagement, the control oil pressure is set higher and the control time is made longer to prevent shock. When starting in reverse first speed R, since the shock is large, the control oil pressure is lowered and the control time is made longer. 1 during the gear shift shown in Fig. 13b.
It depends on the stage control, but from forward 1st speed F ₁ to forward 2
In the case of shifting to speed _F2 and the case of shifting to third forward speed _F3 , the control oil pressure is higher and the control time is longer in the latter case due to the same considerations as at the time of starting described above. Figures 14a and _14b show consideration for the case where a jump shift is performed when the vehicle load is small _. When shifting, 1-stage control is used, whereas when shifting from 1st forward speed F ₁ to 3rd forward speed F ₃ , which involves jump shifting, 2-stage control is used, and the control oil pressure at that time is determined based on the energy requirement. This is relatively high in terms of clutch and slip prevention, and conversely, the overall control time is lengthened. Fig. 14b relates to the case of jump shifting between forward first speed _F1 and reverse first speed R. Considering that skip shifting to the reverse side gives a more shock feeling, the control hydraulic pressure in that case is controlled to be lower. It's taking longer time. Figures 15a and 15b show how the hydraulic control mode is changed by the active gear position of the auxiliary transmission 4 when other conditions are the same, and the hydraulic control mode is changed from the case of the 1st auxiliary gear both when starting and when changing gears. For the case of 3rd speed sub-shift,
The control oil pressure is higher and the control time is longer. FIGS. 16a and 16b show the hydraulic control modes set by touch switches 60S, 60S, and 60H shown in FIG. 4, respectively, S mode, M mode, and H mode.
This figure shows how the hydraulic control mode is changed depending on the mode when other conditions are equal. In the H mode, the first and second solenoid valves 13A and 13B are held in the positions shown in Figure 2 as described above, so the normal oil pressure Pa can be quickly obtained (at the time of starting in Figure 16a). ) is substantially maintained as is (during the gear change in FIG. 16b). When the vehicle speed load is high, the shock associated with starting and shifting is small and clutch slip is more likely to occur, and when the vehicle is lightly loaded, shock is more likely to occur. Therefore, S mode and M mode are controlled accordingly. Oil pressure and control times have been changed. By shortening the control time in the M mode, the desired vehicle speed can also be quickly obtained. The control oil pressure data and control time data stored in the oil pressure control information storage means 22 are for achieving the oil pressure control as described above, and in the illustrated example, there are 96 types of oil pressure control as described above. It stores data for 96 groups that match the conditions. Operation of the embodiment Touch switches 59N, 59F 1 , 59 shown in FIG. 4 are used to displace the directional control valves _1A , 1B.
When one of F ₂ , 59F ₃ , and 59R is operated, if either touch switch 60M or 60S of the hydraulic control mode setting means 19 is operated and the same operation is stored, the oil pressure is The control is performed as described above as a function of the invention.
If the flow of control at this time is shown by taking the case shown in Table 1 above as an example, it will be as shown in the flowchart shown in FIG. 17, as is already clear from the explanation up to this point. That is, when a series of addresses m ₀ , m ₁ , m ₂ , m ₃ are specified by the address designation means 24, the address m ₀ of the hydraulic control information storage means 22 is read and the necessary control oil pressure data is stored in the control oil pressure setting means. 25, said means 25 producing a hydraulic control table corresponding to FIG. Next, the address _m1 is read and the necessary control time data is stored in the timer means 26.
is given to the loop counter, and the count value also sets the control time. loop counter 1
For each output, the comparison means 27 refers to the oil pressure setting tape for the oil pressure measured by the oil pressure sensor 20, and the first and second electromagnetic valve 13
A signal for controlling the positions of A and 13B is output from the hydraulic control signal generating means 28. The illustrated timer means 26 waits for 1 msec here, and then it is determined whether the control time has elapsed based on whether the count number of the loop counter has reached the set count value. If so, the loop counter further outputs and the same hydraulic control as described above is performed by referring to the hydraulic pressure setting table, and when the control time has elapsed, the loop counter is reset and the address is incremented. Thereafter, second-stage control is performed in the same manner, and overall hydraulic control as illustrated in FIG. 5a is achieved. If the touch switch 60H is operated in the hydraulic control mode setting means 19, the address designation means 24 gives a reset signal to the changeover valve operation determination means 23 without performing address designation. Therefore, if the operation of the switching valves 1A and 1B is a starting operation, the hydraulic control as illustrated in FIG. 12a is performed, and if the operation is a gear change operation, the hydraulic control as illustrated in FIG. . Such hydraulic control corresponds to the above-mentioned shock shift, which is one of the problems with the prior art, and allows for a shock shift that was impossible with the prior art.
In other words, when you want the vehicle to run like a dumpster, or when you are doing heavy towing work such as trencher work or deep-plow rotary work, and the vehicle will stop if you do not perform an instant gear change, use the touch switch 6.
By operating 0H, you can achieve shock shifting. Modification Example FIG. 18 shows a vehicle that does not have the sub-transmission device 4, in which the sub-gear detection means 21 of the above-mentioned embodiment is removed, and the addressing means 24 is replaced with the switching valve operation determining means 23 and the hydraulic control mode. Setting means 1
A modification example is shown in which address designation is performed by signal input from 9. In this modification, the hydraulic control mode setting means 19 has four modes, ie, M mode similar to the above, and S mode.
mode, HH mode, which corresponds to the above-mentioned H mode, and H mode, which is a mode for heavy towing work but when the vehicle load caused by the towing work equipment is slightly small.
The mode can be set. In other words, as shown in FIGS. 19a and b, which are graphs corresponding to the cases shown in FIGS. 16a and b,
The H mode is designed to obtain hydraulic control with a high control oil pressure and a short control time, so even when the load is relatively small, although it is heavy towing work, starting and shifting of the vehicle can be controlled by the operator. This is done in such a way as to give the best feeling. It is also possible to configure the electronic control mechanism to enable three-stage hydraulic pressure control or more multi-stage control as illustrated in FIG. 20. Furthermore, in the illustrated example, all the elements of the electronic control mechanism are built into the microcomputer 48, but as can be understood from the equivalent circuit described above with reference to FIG. It can be replaced with the type. Effects of the Invention The hydraulic control device of the present invention has a structure in which the clutch operating hydraulic pressure is controlled by changing and controlling the spring load of the hydraulic pressure setting spring 6 of the pressure regulating valve 5 that sets the normal hydraulic pressure to be applied to the hydraulic clutch.
The position control of the control piston 8 for changing and controlling the spring load is performed by a first solenoid valve 13A inserted into a first circuit 10 that connects the rear of the piston 8 to a clutch oil supply circuit 9 and a first solenoid valve 13A that connects the rear of the piston 8 to a clutch oil supply circuit 9. The structure is obtained by supplying oil from the oil supply circuit 9 to the rear of the control piston 8 and draining oil from the same rear by a second solenoid valve 13B inserted in the second circuit 12 connected to the tank. Since the throttle is not included in the clutch action hydraulic pressure control mechanism, the above-mentioned restrictions on hydraulic pressure control, which were present in conventional systems equipped with a throttle, are removed. This invention also provides both the above-mentioned solenoid valves 13A, 1.
The clutch action oil pressure is controlled by changing the position of the solenoid valve 3B according to the planned control oil pressure and control time. 27, the set control oil pressure is compared with the clutch action oil pressure detected by the oil pressure sensor 20 to perform feedback control to maintain the clutch action oil pressure at the set control oil pressure. A pair of solenoid valves 13 that control oil supply and discharge without using a throttle.
A, 13B, the control piston 8 which determines the clutch working oil pressure is accurately controlled to the intended position, and therefore the clutch working oil pressure can be precisely controlled. In this way, this invention eliminates the throttle from the clutch hydraulic pressure control mechanism, thereby making it possible to freely change and control the clutch hydraulic pressure without being restricted by the throttle, and without being influenced by pump rotational speed or oil temperature. In addition to precisely performing the same hydraulic control using feedback control, the displacement and vehicle load between the two positions of the directional control valves 1A and 1B, which change and control the gears of the hydraulic clutch type transmission, are determined to be possible. In view of the fact that the optimum hydraulic control mode differs depending on the size of
A switching valve operation detection means 18 is provided to detect the displacement between the two positions of B, and a hydraulic control mode setting means 19 is provided which can manually set the magnitude of the vehicle load. 2
The present invention has a structure in which the respective conditions are determined based on the signals from the means 18 and 19, and hydraulic control information corresponding to the conditions is retrieved from the storage means 22, and hydraulic pressure control adapted to the respective conditions is performed. According to the system, it is possible to perform accurate hydraulic control that adapts to a variety of conditions, such as starting or shifting a vehicle, shifting between two gears in a hydraulic clutch type transmission, and the size of the vehicle load. . The clutch hydraulic pressure is controlled by controlling the position of a pair of solenoid valves 13A and 13B without using a throttle, and the vehicle load can be manually set, and when the load is large, the hydraulic pressure is controlled accordingly. Due to the structure that has been adopted, the above-mentioned shock shifting method rapidly increases the clutch working oil pressure when the vehicle is started, and allows the vehicle to start or change the vehicle speed in a dazzling manner without substantially reducing the clutch working oil pressure during gear shifting. Also, it is possible. Regarding the above-mentioned jump shift that does not go through an intermediate gear, control can be performed in accordance with the hydraulic control data so that no shock occurs during such a shift and the vehicle speed change is achieved in as short a time as possible. Therefore, it is necessary to adopt a method that requires a considerable amount of extra time to reach a predetermined vehicle speed, such as shifting from an intermediate gear to a new gear after a certain period of time to prevent shock during a jump shift. Therefore, the desired vehicle speed can be achieved as quickly as possible without causing a shock. The second invention is a vehicle equipped with a hydraulic clutch type main transmission 3 and an auxiliary transmission 4 connected in series thereto. Since the data suitable for the operating gear of the sub-transmission device 4 can be retrieved from the data group stored in the hydraulic control information storage means 22, the storage means 22
In addition to the above-mentioned conditions, by storing data suitable for each operating gear stage of the sub-transmission device 4, it is possible to provide two types of transmission devices 3 and 4 and to perform extremely multi-stage shifting. It is assumed that the above-mentioned accurate hydraulic control can be obtained even in the vehicle transmission.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an electronic control mechanism in one embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram and longitudinal sectional view showing a hydraulic circuit and pressure regulating valve structure in the same embodiment, and FIG. 3 is a diagram showing the same embodiment. FIG. 4 is a schematic diagram of the microcomputer provided in the above embodiment, and a circuit diagram of the external electric circuit of the microcomputer; FIG. 5a, 6 and 7 are hydraulic circuit diagrams for explaining the operation, and FIG. 8 is a hydraulic sensor installed in the above embodiment. FIG. 9 is a vertical cross-sectional view of a part of the self-propelled working vehicle, FIG. 10 is an electric circuit diagram showing an analog equivalent circuit of the main part of the electronic control mechanism in the above embodiment, and FIG. Fig. 11 is a schematic diagram for explaining the oil pressure setting, Fig. 12 a, b are schematic graphs for explaining the hydraulic control action, Fig. 13 a, b, Fig. 14 a, b, 1st
5a, b and 16a, b are schematic graphs for explaining the settings of the hydraulic control mode, respectively, and FIG. 17 is a flowchart for explaining the hydraulic control action in the above embodiment, 18th
The figure is a block diagram showing an electronic control mechanism in another embodiment, Figures 19a and 19b are schematic graphs for explaining the hydraulic control action, and Figure 20 shows the hydraulic control action in another mode. This is a schematic graph for explanation. 1A, 1B... Directional switching valve, 2F ₁ , 2F ₂ , 2
F ₃ , 2R...Hydraulic clutch, 3...Main transmission (hydraulic clutch type transmission), 4...Sub-transmission (other transmission), 5...Pressure regulating valve, 6...Hydraulic pressure setting spring, 8... Control piston, 9... Oil supply circuit, 10... First circuit, 11... Oil tank,
12... second circuit, 13A... first solenoid valve,
13B...Second electromagnetic valve, 14A, 14B...Solenoid, 17...Valve body, 18...Switching valve operation detection means, 19...Hydraulic control mode setting means, 20
...Hydraulic pressure sensor, 21...Sub-shift detection means,
22...Hydraulic control information storage means, 23...Switching valve operation determination means, 24...Address designation means, 25
...Control oil pressure setting means, 26...Timer means,
27... Comparison means, 28... Hydraulic control signal generating means, 30F ₁ , 30F ₂ , 30F ₃ , 30R... Solenoid, 48... Microcomputer, 49...
...Main gear shift selection signal generating means, 59N, 59F ₁ ,
59F ₂ , 59F ₃ , 59R...touch switch,
60H, 60M, 60S...touch switch, 6
0...Diaphragm, _Rg1 , _Rg2 , _Rg3 , _Rg4 ...
Strain gauge, 65, 65, 65...sensor switch, 67...folkshaft, 6
8...Sub-shift lever, 71...Slot hole.

Claims (1)

[Scope of Claims] 1. In a self-propelled work vehicle whose vehicle speed is changed and controlled by a hydraulic clutch type transmission equipped with a plurality of hydraulic clutches whose operation is controlled by a directional switching valve, the directional switching valve is set at each operating position. This is a hydraulic control device for controlling the hydraulic pressure applied to the corresponding hydraulic clutch when the hydraulic clutch is displaced, and includes: A) a pressure regulating valve 5 for setting the normal hydraulic pressure applied to the plurality of hydraulic clutches described above; The tip of the oil pressure setting spring 6 is received by a control piston 8 that can move forward to a position where a spring load corresponding to the normal oil pressure is obtained, and behind this control piston 8 there is a throttle valve for controlling the oil pressure of the oil supply circuit 9 for the hydraulic clutch. The first step is to guide without intervention.
a circuit 10 and a second circuit 12 connecting the back of the control piston 8 to the oil tank 11,
A first solenoid valve 13A and a second solenoid valve 13B, each having a position for making each circuit conductive and a position for cutting off the circuit, were inserted into the first circuit 10 and the second circuit 12, respectively. B. switching valve operation detection means 18 for detecting a displacement operation between two positions of the directional switching valves 1A and 1B;
A hydraulic control mode setting means 19 for outputting a signal corresponding to the set load state by selectively artificially setting a plurality of load states depending on the magnitude of the vehicle load, and detecting the oil pressure of the oil supply circuit 9. C. A hydraulic pressure sensor 20 is provided to control the hydraulic pressure control information according to the displacement between each of the two positions of the directional control valves 1A, 1B and the magnitude of the vehicle load. When a series of addresses are specified in the hydraulic control information storage means 22 which stores the control time for which the control oil pressure is to be maintained at an address corresponding to each control oil pressure and an address corresponding to each control time, sequentially, Hydraulic control signal storage means 22 capable of outputting a signal corresponding to the control oil pressure and a signal corresponding to the control time stored in the series of addresses in this order.
and a switching valve operation determining means 23 which receives a signal input from the switching valve operation detecting means 18 and determines between which two positions the directional switching valves 1A and 1B have been displaced; and receives a signal input from the hydraulic control mode setting means 19, selects a series of addresses according to the input signal, designates the series of addresses to the hydraulic control information storage means 22, and stores them at the first address of the series of addresses. addressing means 24 for outputting a signal corresponding to the controlled hydraulic pressure;
and a control oil pressure setting means 25 which receives a control oil pressure signal from the oil pressure control information storage means 22, sets the control oil pressure, and gives an address increment signal to the oil pressure control information storage means 22 upon completion of the setting; a timer means 26 which receives a control time signal from the hydraulic control information storage means 22, sets the control time, and gives an address increment signal to the hydraulic control information storage means 22 as the control time elapses; Comparison means 2 operated by receiving a signal input from
7, a comparing means 27 for comparing the output signal of the control oil pressure setting means 25 and the output signal of the oil pressure sensor 20 and outputting a feedback control signal according to the magnitude thereof;
The above-mentioned first solenoid valve 13A and second solenoid valve 13 receive a feedback control signal from
A hydraulic clutch type characterized in that it is provided with a hydraulic control signal generating means 28 for outputting a signal for performing feedback control of the hydraulic pressure set by the pressure regulating valve 5 by selectively displacing the hydraulic pressure control valve B. Hydraulic control device for transmission. 2. A self-propelled type in which the vehicle speed is controlled by changing a hydraulic clutch type main transmission equipped with a plurality of hydraulic clutches whose operation is controlled by a directional switching valve and a sub-transmission connected in series to the main transmission. In a work vehicle, a hydraulic control device for controlling the hydraulic pressure applied to a corresponding hydraulic clutch when a directional control valve for a main transmission is displaced to each operating position, comprising: A. The tip of the oil pressure setting spring 6 of the pressure regulating valve 5, which sets the normal oil pressure to be applied to the hydraulic clutch, is received by a control piston 8 that can move forward to a position where a spring load corresponding to the normal oil pressure is obtained. 8, the first one guides the oil pressure of the oil supply circuit 9 to the hydraulic clutch without going through a throttle.
a circuit 10 and a second circuit 12 connecting the back of the control piston 8 to the oil tank 11,
A first solenoid valve 13A and a second solenoid valve 13B, each having a position for making each circuit conductive and a position for cutting off the circuit, were inserted into the first circuit 10 and the second circuit 12, respectively. B. switching valve operation detection means 18 for detecting a displacement operation between two positions of the directional switching valves 1A and 1B;
A sub-transmission gear position detecting means 21 detects the gear position in an operating state in the sub-transmission device 4, and a load state is set by artificially setting a plurality of load states according to the magnitude of the vehicle load. A hydraulic control mode setting means 19 that outputs a signal corresponding to the state, and a hydraulic pressure sensor 20 that detects the hydraulic pressure of the oil supply circuit 9 are provided; C. Hydraulic control information according to the displacement and the magnitude of the vehicle load is assigned to an address corresponding to each control oil pressure and each control time, including a control oil pressure lower than the normal oil pressure and a control time during which the control oil pressure should be maintained. Hydraulic control information storage means 22 that stores in addresses, and when a series of addresses is designated, it sequentially outputs a signal corresponding to the control oil pressure and a signal corresponding to the control time stored in the series of addresses in this order. Possible hydraulic control signal storage means 22
and a switching operation determining means 23 which receives a signal input from the switching valve operation detecting means 18 and determines between which two positions the directional switching valves 1A and 1B have been operated to displace; and this switching valve operation determining means 23. Receiving signal inputs from the above-mentioned auxiliary transmission gear stage detection means 21 and hydraulic control mode setting means 19, selecting a series of addresses according to the input signals, and designating the series of addresses to the above-mentioned hydraulic control information storage means 22. Address designation means 24 outputs a signal corresponding to the control oil pressure stored at the first address of the series of addresses, and a control oil pressure signal is input from the oil pressure control information storage means 22 to set the control oil pressure and upon completion of the setting. A control oil pressure setting means 27 provides an address increment signal to the oil pressure control information storage means 22, and a control time signal is inputted from the oil pressure control information storage means 22 to set the control time and adjust the oil pressure as the control time elapses. Timer means 26 for providing an address increment signal to the control information storage means 22
and a comparison means 27 which is operated upon receiving a signal input from the timer means 26, which compares the output signal of the control oil pressure setting means 25 and the output signal of the oil pressure sensor 20, and performs feedback control according to the magnitude thereof. The pressure regulating valve 5 is operated by a comparing means 27 that outputs a signal, and by selectively displacing the first electromagnetic valve 13A and the second electromagnetic valve 13B by receiving a feedback control signal from the comparing means 27. a hydraulic control signal generating means 28 for outputting a signal for performing feedback control of the set hydraulic pressure;
A hydraulic control device for a hydraulic clutch type transmission, characterized by the following.