JPS6196245A - Vehicle incorporating automatic speed change gear - Google Patents

Abstract

PURPOSE:To satify the drive feeling of a vehicle, by issuing a signal for instructing the engagement of a clutch when the rotational speed of an input shaft coincedes with that of an output shaft. CONSTITUTION:Rotational speed sensors 154, 160 are provided to clutch input and output shafts 18, 22, respectively. Further, outputs from these sensors 154, 160 are delivered to an ECU 80 which delivers a signal for instructing the engagement of a clutch, to a clutch actuator 32 when the rotational speed of the input shaft coincides with that of the output shaft. With this arrangement the clutch input shaft 18 is coupled with the output shaft 22 when the rotational speed of the former coincides with that of the latter upon shift-down of the speed change gear. Thereby, it is possible to eliminate shocks generated upon shift-down of the speed change gear, thereby the drive feeling of the vehicle may be satisfied.

Description

Detailed Description of the Invention Technical Field The present invention provides a power transmission device that transmits the output of an engine to drive wheels, and in which a clutch and a transmission are provided, and after a clutch engagement/disengagement actuator disengages the clutch, a shift The invention relates to a vehicle with an automatic transmission configured such that an actuator for shifting the transmission shifts the transmission, and an actuator for connecting and disconnecting the clutch connects the clutch again.

As mentioned above, one type of conventional automatic transmission vehicle includes a clutch and a transmission in a power transmission device that transmits the output of an engine to drive wheels, and also includes a clutch connection/disconnection actuator and a shift actuator. Some actuators are equipped with such actuators to automatically control the gear ratio by engaging and disconnecting the clutch and shifting the transmission.

By the way, in this type of automatic transmission vehicle, conventionally, a clutch engagement command signal is issued immediately after the shift operation of the transmission by the shift actuator is completed, and as soon as this clutch engagement command signal is issued, the clutch engagement/disengagement actuator is activated. The clutch was now connected.

Problems to be Solved by the Invention For this reason, in conventional vehicles with this type of automatic transmission, the engine rotational speed and the rotational speed of the transmission input shaft (clutch output shaft) do not match after the transmission is shifted. Especially when downshifting, the engine speed becomes too low, resulting in sudden engine braking, which makes the ride uncomfortable.

Means for Solving the Problems The present invention eliminates the above-mentioned problems that occur during shift I/down of the transmission, and provides an automatic transmission (=
This was done to provide J heavy vehicles, and its gist is to detect the input shaft rotational speed of the input shaft of ta + clutch, a detection means; fb) an output shaft rotation integer detection means for directly or indirectly detecting the rotation speed of the output shaft after the clutch has shifted down; and (C) an input shaft rotation speed after the shift actuator has shifted down the transmission. engine rotation speed control means for controlling the engine rotation speed so that the detection result of the detection means matches the detection result of the output shaft rotation speed detection means; A comparison means is provided which compares the detection result of the detection means and issues a clutch engagement command signal to the clutch engagement/disengagement actuator when the two match.

By doing so, when the transmission is downshifted, the input shaft of the clutch is connected to the output shaft in a state where its rotational speed matches the rotational speed of the output shaft.

Effects of the Invention In other words, after the transmission has been downshifted, the clutch is prevented from being engaged while the engine rotational speed is too low compared to the rotational speed of the input shaft of the transmission, that is, the output shaft of the clutch. Therefore, the shock that occurs when the transmission is downshifted can be eliminated, and the ride comfort can be improved. Moreover, the control of the engine speed for this purpose is completely automatic, and the driver does not have to perform any particular operation, so that a vehicle with good drivability can be obtained.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

First, FIG. 1 shows a power transmission device for a forklift truck, which is an embodiment of the present invention. As is clear from this figure, in this embodiment, the rotation of the engine 10 is transmitted to the left and right drive wheels 16 via the clutch 12 and the transmission 14. The rotation speed of the engine 10 is controlled by controlling the throttle opening degree by a stepping motor 17, and the driving control of the stepping motor 17 is controlled by an electronic control unit (hereinafter referred to as ECU) 80, which will be described later. It is now possible to do so.

The clutch 12 connects the flywheel 20 fixed to the output shaft 18 of the engine 1o and the input of the transmission 14! 1lI2
A clutch disc 24 is attached non-rotatably and movably in the axial direction to the flywheel 2 , and a clutch disc 24 is attached to the flywheel 20 , facing the flywheel 20 with the clutch disc 24 in between.
A pressure plate 26 is provided so as to be non-rotatable relative to zero and movable in the axial direction, and the clutch disk 24 is normally moved between the flywheel 20 and the pressure brake based on the force of the clutch spring 28.
Engine 1 is sandwiched between I-26 and I-26.
0's output shaft 18 and the input shaft 22 of the transmission 14 are connected,
The rotation of the output shaft 18 of the engine 10 is transmitted to the input shaft 22 of the transmission 14. When the clutch engagement/disconnection actuator 32 is operated, the pressure plate 26 is separated from the flywheel 20 by the actuation arm 34 driven by the clutch engagement/disconnection actuator 32 against the biasing force of the clutch spring 28. By releasing the clutch disc 24 between the flywheel 2o and the pressure plate 26, the connection between the output shaft 18 of the engine 10 and the input shaft 22 of the transmission 14 is released, and the output shaft 18 of the engine 10 is disconnected. Rotation is prevented from being transmitted to the input shaft 22 of the transmission 14. That is, the output shaft 18 of the engine 10 and the input shaft 22 of the transmission 14 serve as the input shaft and output shaft of the clutch 12, respectively, and the clutch 12 serves as the input shaft when the clutch engagement/disconnection actuator 32 is not operated. (Engine output shaft 18) is connected to the output shaft (transmission input shaft 22), and when the clutch connection/disconnection actuator 32 is operated, the input shaft and output shaft are disconnected.

The transmission 14 also includes a gear ratio switching gear section 36 for switching between 1st and 2nd speeds and a forward/reverse switching gear section 38, and changes the rotation of the engine 10 transmitted to the input shaft 22 via the clutch 12. Ratio switching gear section 36 and forward/reverse switching gear section 3
8, the signal is transmitted from the output shaft 40 to the left and right drive wheels 16. The input shaft 22 has a first gear shifter 4.
2 and the second speed manual gear 44 are fixed, and the first
It is meshed with a continuous reduction gear 46 and a second continuous reduction gear 48. Further, a connecting gear 50 is fixed to each of these reduction gears, and these connecting gears 50 are connected to both gear portions 36.
and 38, and is disposed coaxially with and sandwiching the output gear 54, which is fixed to a connecting shaft 52 that connects the output gears 52 and 38. Then, a shift internal gear 5 is attached to the outer periphery of these gears.
A first speed shift position in which the output gear 54 is connected to the first speed side connecting gear 50 by the shift actuator 58, and a second speed shift position in which the output gear 54 is connected to the second speed side connecting gear 50. and an intermediate neutral shift position that is not connected to any of the connecting gears 50. When the internal gear 56 is moved to the neutral shift position by the shift actuator 58, no rotation is transmitted to the connecting shaft 52, but when the internal gear 56 is moved to the first shift position, the rotation of the input shaft 22 is transmitted to the first gear shift position. Continuous input gear 42
．． Connection shaft 52 via reduction gear 46 and connection gear 50
The rotation of the input shaft 22 is transmitted to the second gear input gear 44 when it is moved to the second gear shift position.
．． Connection shaft 52 via reduction gear 48 and connection gear 50
It is designed to be transmitted to

On the other hand, a forward/reverse input gear 60 is fixed to the connecting shaft 52, and is disposed coaxially with the forward connecting gear 62 and the reverse connecting gear 64 while being sandwiched between them. On the outer periphery of these gears, there are a forward position where the input gear 60 is connected to the forward connecting gear 62 by the forward/reverse switching actuator 66, a reverse position where the input gear 60 is connected to the reverse connecting gear 64, and a position where the input gear 60 is not connected to any connecting gear. A forward/reverse switching inclination gear 68 is provided which can be moved between three positions including a neutral forward/reverse position located between these positions. The rotation transmitted to the forward connecting gear 6o via the ink null gear 68 is transmitted from the forward input gear 70 fixed to the gear 60 to the output shaft 4o via the forward output gear 72, and The rotation transmitted to the connecting gear 64 is transmitted to the output shaft 4o via the reverse input gear 741, the reverse gear 76, and the reverse output gear 78, and is transmitted to the drive wheels 16 via the output shafts 40, respectively. .

As described above, in this embodiment, the engagement and disengagement of the clutch 12, the switching of the gear ratio in the transmission 14, and the switching of forward and backward movement are performed by the clutch engagement and disengagement actuator 32. This is performed by the shift actuator 58 and the forward/reverse switching actuator 66, but in this embodiment, these actuators are all hydraulic cylinders, and are driven by a hydraulic circuit controlled by the ECU 3O. It has become. Figure 2 shows the hydraulic circuit. The hydraulic circuit shown in Fig. 2 will be explained below, but for ease of understanding, the chamber in the example cylinder head of each actuator (hydraulic cylinder) will be referred to as the head side chamber, and the chamber on the piston rod side will be referred to as the rod side chamber. do.

In FIG. 2, the hydraulic oil pumped up from the tank 82 by the pump 84 is stored in the accumulator 86 and then supplied to the main liquid passage 87, from which the control valve mechanism of the clutch engagement/disconnection actuator 32 is operated. It is supplied directly to a certain clutch control valve mechanism 88, and to a shift control valve mechanism 90 and a forward/reverse switching control valve mechanism 92, which are the control valve mechanisms of the shift actuator 58 and the forward/reverse switching actuator 66, via a main electromagnetic on-off valve 94. It is now possible to do so. The main electromagnetic on-off valve 94 is always closed, so the main fluid is connected to the shift control valve mechanism 90 and the forward/reverse switching control valve mechanism 92 only while the main electromagnetic on-off valve 94 (more precisely, its solenoid) is energized. aisle 8
Hydraulic oil is supplied from 7.

The clutch control valve mechanism 88 includes a first human-powered electromagnetic on-off valve 96 that can rapidly supply hydraulic oil from the main fluid passage 87 to the head side chamber 95 of the clutch connection/disconnection actuator 32, and a throttle. a second human-powered electromagnetic on-off valve 98 that can gradually supply hydraulic oil to the head side chamber 95;
A first output electromagnetic on-off valve 102 that can rapidly discharge the hydraulic oil in the head side chamber 95 to the tank 82 via the drain passage 100.
and a second output solenoid on-off valve 104 which is equipped with a throttle and is configured to gradually discharge the hydraulic oil in the head side chamber 95 into the tank 82 through the drain passage 100. By controlling this, hydraulic oil can be supplied and discharged to and from the head side chamber 95 of the clutch engagement/disconnection actuator 32 at a desired speed.

In the clutch connection/disconnection actuator 32, the piston rod 106 is moved in the air chamber against the biasing force of the thalassochi spring 28 applied via the actuation arm 34 according to the amount of hydraulic oil in the head side chamber 95. Move forward (extension 1 length) to a certain mouth/throat side chamber 107 side,
As mentioned above, the pressure plate 26 is moved in the direction away from the flywheel 20 via the actuation arm 34. In this clutch control valve mechanism 88, only the second output electromagnetic on-off valve 104 is always opened, so the piston rod 106 is always opened in the head side chamber based on the biasing force of the thalassochi spring 28. It is retracted, that is, contracted, to the 95 side.

The shift control valve mechanism 90 consists of two electromagnetic on-off valves 108 and 110 connected in series between the main electromagnetic on-off valve 94 and the drain passage 100, and the shift actuator 58 is connected to the main electromagnetic on-off valve 94 and the drain passage 100. It is connected to a connecting passage 114 connecting these electromagnetic on-off valves, and a rod side chamber 116 is provided in a state connected to the main electromagnetic on-off valve 94.

Both electromagnetic on-off valves 108 and 110 are always open, and hydraulic pressure is not applied to the head side chamber 112 and rod side chamber 116 of the shift actuator 58.

Therefore, in this state, the shift 12
The piston of the actuator 58 is held at an intermediate position between the head side chamber 112 and the rod side chamber 116, and the shift increment gear 56 is held at the bi-tral shift position. On the other hand, when the electromagnetic on-off valve 108 is closed while the main electromagnetic on-off valve 94 is open, hydraulic oil is supplied only to the rod side chamber 116 side, so that the piston rod 118 is contracted and the ink null gear 56 is It is moved to the first gear shift position. Furthermore, when the electromagnetic on-off valve 110 is closed while the main electromagnetic on-off valve 94 is open, hydraulic pressure is applied to both the head side chamber 112 and the rod side chamber 116, so that the head side chamber 112 and the rod side chamber 116 are The piston rod 11B is extended due to the difference in pressure receiving area, and the internal gear 56 is moved to the second speed shift position.

Further, as is clear from FIG. 2, the forward/reverse switching control valve mechanism 92 also consists of two electromagnetic on/off valves 120 and 122 connected in series between the main electromagnetic on/off valve 94 and the drain passage 100. , the head side chamber 124 of the forward/reverse switching actuator 66 connects the two electromagnetic on/off valves.
6, and the rod side chamber 128 is connected to the main electromagnetic on-off valve 94. Both electromagnetic on-off valves 120 and 122 are normally opened to maintain the piston at an intermediate position, and the ink null gear 6 for forward/reverse switching of the transmission 14 is opened.
8 is held in a neutral forward/reverse position, and when the main electromagnetic on/off valve 94 is opened and the electromagnetic on/off valve 120 is closed, the piston rod 130 is contracted and the ink null gear 68 is placed in the forward position. When the main electromagnetic on-off valve 94 is opened and the electromagnetic on-off valve 122 is closed, the piston rod 130 is extended and the ink null gear 68 is moved to the reverse position.

As shown in FIG. 3, the ECU 3O that drives and controls the stepping morph 17 and each electromagnetic on-off valve of the hydraulic circuit is mainly composed of a CPU 134 equipped with a memory 132, and receives input from various sensors. The information stored in the memory 132 in advance is processed by the CPU 13/I according to the programmed program, and each electromagnetic on-off valve, steering wheel, and pin motor 7 of the hydraulic circuit are driven based on the results of the processing. , the CPU 34 has an input interface circuit 138 and an A/
Analog signals such as accelerator depression amount, clutch stroke, and engine cooling water temperature are digitized and input manually through the D converter 40, and forward commands and neutral commands are also transmitted through the interface circuit 142. , reverse command, accelerator idle state, 2-inch idle state, 1st speed shift position state, neutral shift position shift position state, forward position state, neutral forward/backward position state. Reverse position. Various on/off signals such as maximum throttle position, minimum throttle position, engine rotation, transmission input shaft rotation, vehicle speed, brake operation status, and loading oil pressure are input. Further, from the CPU 3 4, a solenoid drive signal for each electromagnetic on-off valve of the hydraulic circuit and the stepping morph 1 are sent via the output interface C ace circuit 144.
7 drive signals are output.

Incidentally, the amount of accelerator depression is determined by the accelerator sensor 14 provided on the accelerator 146, as shown in FIG.
The rotation of the engine, that is, the shaft rotation of the clutch 12 is detected by a rotation sensor 154 consisting of a magnetic gear 150 and a magnetic sensor 152 fixed to the output shaft 18 of the engine 10. The rotation of the shaft, that is, the rotation of the output shaft of the clutch 12 is the rotation of the shaft of the transmission 1.
The rotation sensor 160 includes a magnetic gear 156 and a magnetic sensor 158 fixed to the input shaft 22 of No. 4. Further, the clutch stroke is detected by a potentiometer 162 attached to the clutch engagement/disconnection actuator 32, and each shift position state and each forward/reverse position state is detected by the shift actuator 58 and the forward/reverse switching actuator. It is detected by the operating state of a switch (not shown) provided at 66. Note that other information signals will also be detected by sensors or switches provided correspondingly, but since these are all well known,
The explanation will be omitted.

Next, the operation of this embodiment will be explained according to the flowchart shown in FIG. In addition, below, only the case where the gear ratio of the transmission 14 is shifted between the first speed and the second speed will be explained, and the shift control between neutral and the first speed and the forward/reverse switching control will be explained. is omitted.

When the program reaches star 1, first step 7 step S1
is executed, and it is determined whether the transmission 14 is at the optimum shift position from various information signals input to the ECU 8O. Specifically, when a specific shift control pattern among a plurality of shift control patterns stored in advance in the memory 132 is determined based on various information signals input to the ECU 8O, the shift control pattern is automatically Based on this, the optimum shift position is determined, and it is determined whether the actual shift position matches the optimum shift position. Then, if it is determined that the actual shift position matches the optimum shift position, step S1 is repeated, and if it is determined that they do not match, step S2 is executed.

In step S2, a drive signal for opening the re-input electromagnetic on-off valve 96.98 of the clutch control valve mechanism 88 is supplied, and at the same time, a drive signal is supplied to the re-output electromagnetic on-off valve 102.1.
04 is supplied with a drive signal for closing the valve, hydraulic oil is supplied to the head side chamber 95 of the clutch engagement/disconnection actuator 32, and the disengagement operation of the clutch 12 is started.

After step S2 is executed, step S3 is executed, and it is determined based on the clutch stroke signal supplied from potentiometer 162 whether the clutch disengagement operation is completed.

This step S3 is repeatedly executed until the clutch disengagement operation is completed, but it ends as soon as it is determined that the clutch disengagement operation is completed, and step S4 is continued in step S3.
is executed.

In step S4, a shift 2j transition is performed between the first and second shift positions.

That is, when the shift increment gear 56 is in the first gear shift position, it is moved to the second gear shift position, and conversely, when it is in the first gear shift position, it is moved to the first gear shift position. They are moved.

In Ste Knob S5 executed after the end of Step S4,
Based on the shift position status signal from the switch provided in the shift actuator 58, it is determined whether or not the shift 1 to position changing operation (hereinafter simply referred to as shift) has been completed, and it is determined that the shift has been completed. Then, step S6 is executed. In this shift door knob S6, it is determined whether or not the shift in step S4 was performed (shift door knob force), and if the determination is affirmative, step S7 is subsequently executed, and if the determination is negative, step S8 is executed. be done.

In step S7, which is executed when the determination in step S6 is affirmative, a clutch engagement command signal is issued to close the re-input electromagnetic on-off valves 96 and 98 of the clutch control valve hidden structure 88, and the re-output electromagnetic on-off valves 96 and 98 are closed. Either 102 or 104 is opened, thereby starting to engage the clutch 12.

After this step S7 is executed, step S9 is executed, and it is determined whether or not the engagement operation of the clutch 12 is completed based on the clutch stroke signal from the potentiometer 162. When it is determined that the connection TFI operation is completed, the execution of step S1 is repeated again.

On the other hand, in step S8, which is executed when the result of the judgment in step S6 is negative, that is, in the case of downshifting, the engine rotational speed (clutch input shaft rotation number)
Ni is determined, and in the following step SIO, this engine rotation speed Ni and the gear ratios of the first and second speeds ■□, 1
2, the corrected engine rotation speed Ni'', which is the clutch output shaft rotation speed (transmission input shaft rotation speed) after downshifting, is determined according to the following equation (1).

Ni'=NiX (I/■2) −・−−−−−−(1
, 1 step SIO, when the engine speed Ni'' after the downshift is determined, in the following step Sll, the engine speed corresponding to the corrected engine speed Ni° is determined from the relationship between the engine speed and the throttle opening stored in advance in the memory 132. The throttle opening degree θ'' is determined, and in step S12, which is subsequently executed, the actual throttle opening degree is determined as the throttle opening degree θ1 determined in that step Sll.
The stepping motor 17 is driven to match the . Then, in the following step S13, it is determined whether the actual engine rotation speed (clutch input shaft rotation speed) Ni changed by driving the stepping motor 17 has reached the corrected engine rotation speed Ni′ determined in the step SIO. is judged.

Step S13 is repeatedly executed while the determination result is negative, but if the determination result is affirmative, step S14 is subsequently executed and the driving of the stepping motor 17 is stopped. In other words, these steps Sl
1 to 314, the clutch input shaft rotation speed Ni is adapted to the clutch output shaft rotation speed Ni' after downshifting.

When step S14 is completed, steps S15 and S16, which are similar to steps S7 and S9, are successively executed. That is, in step S15, a clutch engagement command signal is issued, the clutch control valve mechanism 8B is driven and controlled, and the engagement operation of the clutch 2 is started.
In step S16, it is determined whether the touch operation is completed. When it is determined in step 316 that the engagement operation of the clutch 12 is completed, step S17 is subsequently executed, and the stepping motor 17 is
is driven, the throttle openings 1 to 3 are made to match the openings corresponding to the amount of accelerator depression, and then step S1 is repeated again.As explained above, in this embodiment, the transmission 14 is shifted down from second speed to first speed, the rotational speed of the input shaft of the clutch 12 (output shaft 18 of the engine 10) changes while the clutch 12 is in the disengaged state. The rotation speed of the engine 10 is prevented from becoming too low when the clutch 12 is engaged, and the engine speed is adjusted to match the rotation speed of the output shaft (input shaft 22 of the transmission 14). This will eliminate the problem of the brakes being applied.

Note that, as is clear from the above explanation, in this example,
Rotation sensor 154 and CPU 13 that executes step S8
4 constitutes an input shaft rotation speed detecting means for the clutch and clutch 12, and similarly, the rotation sensor 154 and the CPU 34 that executes step SIO detect the rotation speed of the clutch output shaft after the downshift to the rotation speed before the downshift. A first output shaft rotation speed detecting means is configured to indirectly detect the change in the gear ratio before and after downshifting. Further, an engine rotation speed control means is constituted by a CPtJ 134 that executes steps Sll and 312, a stepping motor 17, and a throttle valve whose valve opening is controlled by the stepping motor 17, and a CPU that executes steps S13 and S15.
134 constitutes a comparison means.

Next, another embodiment of the present invention will be described. Note that this embodiment differs only in operation from the previous embodiment, so
The operation will be explained below according to the flowchart shown in FIG.

In this embodiment, first, step S similar to the previous embodiment is performed.
1 is executed, but if it is determined in this step S1 that it is necessary to shift the gear ratio, step 86' is subsequently executed, and it is determined whether to shift the shift amplifier or downshift. A judgment is made. If it is determined in step S6" that the shift amplifier should be activated, steps S2 and S3 similar to those in the above embodiment are executed successively, and the clutch 2 is disengaged. Then, in step S3 Subsequently, step S4'' is executed, and the shift position of the shift increment gear 56 of the transmission 14 is moved from the first gear shift position to the second gear shift position. When step S4' is completed, step S4' similar to the above embodiment is
5. S7 and S9 are executed successively, and it is confirmed that the upshift operation of the transmission 14 is completed, and the clutch 12 is engaged. After the engagement operation of the clutch 12 is completed, the step S1 is repeated.

On the other hand, if it is determined in step S6° that a downshift should be performed, step 38' is immediately executed, and the output shaft of the clutch 12 ( Transmission input shaft 22
) is detected. And then step 8
10', the output shaft rotational speed NO detected in step S8' and the gear ratio 11 of the first speed and second speed are determined.
and (2), the corrected engine speed Ni'' after the downshift is determined based on the following equation (2), and then, in step Sll similar to the above embodiment, the throttle opening θ is adjusted according to the speed Nil. “is sought and memorized.

N i' -N o X (I s / 12)
−1−−−−−−(21) As is clear from this equation (2), the rotation speed NO obtained in step S8″ is equal to the engine rotation speed Ni obtained in step S8 of the above embodiment. is equivalent to

When the throttle opening degree θ° corresponding to the corrected engine speed Ni° is determined in step 311, steps 32' and 83'' similar to steps S2 and S3 are executed, and the clutch 12 is disengaged. Thereafter, step 84'' is executed to start shifting the shift increment gear 56 from the second speed shift position to the first speed shift position.

When step 84'' is executed, steps S12, S13 and S14 similar to those in the above embodiment are executed, and the actual engine rotation speed N+ is set to 310°.
It is made to match the corrected engine rotation speed Ni° obtained in . That is, in step S12, the stepping motor 7 is adjusted so that the actual throttle opening matches the throttle opening θ9 stored in step 311.
is started, and in step S13, it is determined whether or not the actual engine rotation speed Ni has reached the corrected engine rotation speed N I + determined in step S10''. The driving of the stepping motor 7 is stopped in S14. Then,
Thereafter, Step 7 S5', which is similar to the embodiment described above, is executed, and it is determined whether or not the shift operation has been completed. That is, in this embodiment, the shift operation of the transmission 14 and the engine 1
The control operation for the rotation speed of 0 is performed in parallel.

When it is determined in step S5' that the shift operation has been completed, steps similar to step 315 and subsequent steps of the embodiment described above are performed, and the clutch 12 is engaged and the engine throttle opening is adjusted after the clutch is engaged. is adjusted according to the amount of accelerator depression, and then step S1 is repeated as in the embodiment described above.

Also in this embodiment, the clutch input shaft rotational speed (engine rotational speed) when the clutch is engaged matches the clutch output shaft rotational speed, and the shock during downshifting is eliminated. Note that, as is clear from the above description, in this embodiment, the rotation sensor 160 and step 3
8' and the CPU 134 that executes SIO' constitute an output shaft rotation speed detection means.

Next, still another embodiment of the present invention will be described based on FIG. 6. This embodiment is almost the same as the first embodiment, so only the marginal parts will be explained below.

That is, in this embodiment, as shown in FIG. The rotational speed of the clutch output shaft (transmission input shaft 22) after downshifting, that is, the corrected engine rotational speed Ni' is directly detected, and in the following step Sll, the throttle opening degree θ゛ is determined according to the corrected engine rotational speed Ni'. Hereafter, the engine speed, that is, the clutch input shaft speed, is controlled based on the throttle opening θ'' and the engine speed Ni1.

Even in this manner, the object of the present invention can be achieved. In this embodiment, the rotation sensor 160 and the CPU 134 that executes step 88'' constitute output shaft rotation speed detection means that directly detects the rotation speed of the clutch output shaft after downshifting.

Although several embodiments of the present invention have been described above, these are literally illustrative, and the present invention should not be construed as being limited to these specific examples.

For example, in the embodiment described above, the corrected engine speed N+" is calculated indirectly from the engine speed Ni before downshifting and the clutch output shaft speed No (=Ni), or the clutch output after the shift operation is calculated. Although the corrected engine rotation speed Ni'' was directly detected from the shaft rotation speed, the corrected engine rotation speed Ni'' may also be determined from the vehicle speed before or after the shift operation.

Furthermore, in the embodiment described above, only the engine rotation speed (clutch input shaft rotation speed) after downshifting is adapted to the corrected engine rotation speed (clutch output shaft rotation speed) Ni' when the clutch is engaged. It is also possible to adapt the engine speed after the shift amplifier to the clutch output shaft speed Ni''.

Further, in the embodiment, the clutch connection/disconnection actuator 32. Although the shift actuator 581 and the forward/reverse switching actuator 66 are both hydraulic cylinders, each of these actuators may be a hydraulic actuator other than a hydraulic cylinder, or may be an electric actuator.

Further, in the embodiment described above, the output shaft 18 of the engine 10 is directly used as the input shaft of the clutch 12, and the rotation speed of the engine 10 is directly the rotation speed of the input shaft of the clutch 12. It does not need to be the input shaft of the clutch, and their rotational speeds do not necessarily have to be the same.

In short, it is sufficient to control the engine speed so that the clutch input shaft speed after downshifting matches the clutch output shaft speed when the clutch is engaged.

Further, in the above embodiments, the number of gears is two, but the present invention can also be applied to a vehicle having three or more gears.

Further, in the above embodiment, the power transmission device was equipped with only one clutch 12 common to both forward and reverse motions, but in the present invention, the transmission is a planetary gear unit of a constant mesh type. In addition, the present invention can also be applied to a vehicle equipped with a power transmission device including a plurality of clutches, such as a forward clutch and a reverse clutch.

Further, although the present invention is most suitably applied to industrial vehicles such as the forklift truck of the above embodiment, it can also be applied to other vehicles such as passenger cars.

Although not listed here, it goes without saying that the present invention can be practiced with various modifications and improvements without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a power transmission device for a forklift truck that is an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of a hydraulic circuit for operating each actuator shown in FIG. 1. 3 is a flowchart for explaining the electronic control device shown in FIG. 1, and FIG. 4 is a flowchart for explaining the main parts of the operation of the power transmission device shown in FIG. 1. 1. FIG. 5 and FIG. 6 are flowcharts 1 to 1 for explaining the main parts of the operation of different embodiments of the present invention, respectively. 10: Engine 12: Clasochi 14: Transmission 16: Driving wheel 17: Stesoping motor 18: Engine output shaft (clutch manual shaft) 22: Transmission input shaft (clutch output shaft) 32: Clutch connection/disconnection actuator 58: Shift Actuator 66: Forward/forward switching actuator 80: Electronic control device 88: Krasochi control valve mechanism 90: Shift control valve mechanism 92: Forward/forward switching control valve mechanism 148: Accelerator sensor 154.160: Rotation sensor Henun Sakura Turnover 2 electric shift
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Claims (1)

[Claims] A clutch and a transmission are provided in a power transmission device that transmits the output of an engine to drive wheels, and after a clutch engagement/disconnection actuator disengages the clutch, a shift actuator engages the transmission. In a vehicle with an automatic transmission configured such that the clutch is shifted and the clutch is engaged again by the clutch engagement/disconnection actuator, an input shaft rotation speed detection means for detecting the rotation speed of the input shaft of the clutch; Output shaft rotation speed detection means directly or indirectly detects the rotation speed of the output shaft after downshifting; and after the shift actuator shifts down the transmission, the detection result of the input shaft rotation speed detection means is detected as the output shaft an engine rotation speed control means that controls the rotation speed of the engine so as to match the detection result of the rotation speed detection means; and a comparison between the detection result of the input shaft rotation speed detection means and the detection result of the output shaft detection means. and a comparison means for issuing a clutch engagement command signal to the clutch engagement/disengagement actuator when both are compatible.