JP2002276798A - Hydraulic device for clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic device for a clutch for achieving a gently rising hydraulic pressure waveform in starting and forward/reverse gear change and permitting the pressure rise of the clutch quickly after clutch connection. SOLUTION: A modulation valve 22 and a duty valve 91 are provided for selectively forming the rising pressure waveform of an operating oil to be supplied to the hydraulic clutch of a transmission after gear change in response to clutch changing operation (the operation of a change lever of the transmission). In this construction, the waveform of the pressure rise of the operating oil to be supplied to the hydraulic clutch after gear change is selectively formed, and so the clutch hydraulic pressure can rise up to the maximum pressure quickly after clutch connection and a time for the clutch hydraulic pressure to reach the maximum pressure can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch hydraulic device for a transmission of an industrial vehicle (for example, a wheel loader or a forklift) using a torque converter.

[0002]

2. Description of the Related Art One example of the conventional clutch hydraulic device is as follows.
A description will be given based on FIG. In FIG. 10, reference numeral 1 denotes a charging pump (an example of an oil pump), and hydraulic oil discharged from the charging pump 1 is supplied to a line filter 2.
, The pressure is adjusted by the transmission control valve 3 and supplied to the torque converter 4,
Subsequently, it is cooled by the oil cooler 5 and supplied as lubricating oil for the transmission device. A safety valve 6 is provided at the inlet of the torque converter 4. In FIG. 10, reference numeral 7 denotes an oil tank (transmission sub-tank).

[0003] The transmission control valve 3 has a regulator for adjusting the pressure of the hydraulic oil and supplying the pressure to the torque converter 4 as described above.
Hydraulic oil is applied to each hydraulic clutch, that is, a forward (FWD) hydraulic clutch 11, a reverse (REV) hydraulic clutch 12, and a first speed (1ST) hydraulic clutch, which is a speed clutch.
13, a second-speed (2ND) hydraulic clutch 14, a third-speed (3RD) hydraulic clutch 15, a fourth-speed (4TH) hydraulic clutch 16, and a valve body and a plurality of valves for selectively changing the direction and speed of the vehicle. It has a solenoid valve (not shown). Transmission control valve 3
Clutch operation lever (forward / reverse / 1st / 2nd / 3rd /
A signal corresponding to an operation signal of (fourth speed) is input, and the solenoid valves are actuated according to these operation signals, and the spool in the valve is moved to control the clutch oil pressure. In the torque converter type transmission, (1) forward (or reverse) hydraulic clutch 11 or 12 (2) speed stage hydraulic clutch 13 or 14 or 15 or
The speed stage is set by the engagement of the two clutches.

As shown in FIG. 11, the module mechanism of the control valve 3 changes the pressure increase time (clutch oil pressure waveform) of the clutch oil pressure according to each speed stage to enable a smooth gear shift. When the operation is performed, the clutch hydraulic pressure Pa at the “before shifting” speed stage
After returning to 0 promptly, the clutch oil pressure Pb "after shift" is gradually increased to complete the shift.

[0005]

However, the conventional transmission clutch hydraulic device has the following problems.

[0006] The clutch oil pressure P after "shift" for each speed stage
When the waveform b is changed, a smooth feeling is obtained at any speed stage, but only three types of limited inclinations can be formed. Also, as shown in FIG. 12, at the time of shifting, the pressures of both the forward (or reverse) hydraulic clutch 11 (or 12) and the speed stage hydraulic clutch 13 or 14 or 15 or 16 instantaneously decrease, and the drive Because loss of power occurs,
This gives the operator an uncomfortable feeling such as a feeling of torque loss or shock during shifting and a feeling of returning on a slope.

Further, depending on the state of the vehicle (the magnitude of the engine rotation, the magnitude of the vehicle speed) or the type of shift (start, upshift, downshift, forward / reverse switching), there are cases where the clutch is engaged in a relatively short time, There is a case where the connection is made by slipping for a long time, but it is necessary to adjust the hydraulic waveform to the longer one. For this reason, it is not possible to prevent the load from the vehicle from increasing after shifting and re-slip the vehicle by setting the torque transmission capacity to the maximum required for the transmission by quickly increasing the pressure to the maximum pressure after the connection. For example, the time until the clutch “after shift” slips and the shift is completed (clutch slip time) at the time of gear shifting in the order of downshifting, upshifting, starting, and forward / reverse switching (clutch slip time) becomes longer. Since the reduction ratio of the transmission is large, if the speed is not increased gradually (unless the clutch slip time is increased), the shock is large when the clutch is engaged, and a long time (for example, 2.8 seconds) is required to increase to the final pressure. However, the clutch slip time for downshifting from the second gear to the first gear is only 0.2 to 0.1.
Three seconds is sufficient. Therefore, at the time of such a downshift, it is not possible to increase the pressure to the maximum pressure rapidly during the remaining time. In addition, the clutch slip time of the first speed forward / reverse switching is
It requires a long time of 1.1 to 1.4 seconds.

Accordingly, the present invention can realize a gentle rising hydraulic pressure waveform when switching between starting and moving forward and backward, and immediately increases the clutch pressure after the clutch is engaged (after the clutch after "shift" slips and the shift is completed). It is an object of the present invention to provide a clutch hydraulic device that can move up and further reduce the time required to disengage a clutch “before shifting” when downshifting or upshifting.

[0009]

In order to achieve the above-mentioned object, according to the present invention, in an industrial vehicle using a torque converter, a transmission change lever is connected to each hydraulic clutch of the transmission in an industrial vehicle. A clutch hydraulic device that selectively feeds oil according to an operation, characterized by comprising pressure adjusting means for arbitrarily forming a boosted waveform of hydraulic oil supplied to a hydraulic clutch after shifting.

According to the above arrangement, the pressure adjusting means can arbitrarily form a waveform of a pressure rise of the hydraulic oil supplied to the hydraulic clutch after the gear shift. Therefore, it is possible to shorten the time until the clutch hydraulic pressure reaches the maximum pressure.

According to a second aspect of the present invention, in the first aspect of the present invention, when the hydraulic clutch after shifting is connected by the supply of the hydraulic oil, the pressure adjusting means is configured to control the pressure of the hydraulic oil. Is rapidly increased.

According to the above structure, when the clutch after the shift is engaged, the pressure of the hydraulic oil supplied to the hydraulic clutch after the shift is quickly increased, and the time required for the clutch oil pressure to reach the maximum pressure is shortened. Re-slip is prevented.

According to a third aspect of the present invention, in the first or second aspect of the present invention, at the time of shifting, the holding means for holding the hydraulic oil supplied to the hydraulic clutch before the shifting for a certain period of time. It is characterized by having.

According to the above configuration, a part of the hydraulic oil supplied to the hydraulic clutch before the gear shift is held for a certain period of time at the time of gear shifting, thereby preventing the drive force from being lost due to a decrease in the clutch oil pressure at the time of gear shifting.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the pressure adjusting means is provided with a shifting mechanism held by the holding means when the hydraulic clutch is downshifted or upshifted. It is characterized in that the hydraulic oil supplied to the previous hydraulic clutch is reduced in a short time.

According to the above construction, the amount of hydraulic oil held by the holding means is reduced in a short time, so that the time from the start of the shift to the disengagement of the clutch before the shift is shortened, so that a quick feeling can be obtained. can get.

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the pressure adjusting means is operated by operating a transmission change lever. Is what you do.

According to the above construction, the pressure adjusting means is operated by operating the transmission change lever,
An arbitrary boost waveform after the shift is formed.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those in FIG. 10 of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a hydraulic circuit diagram of a transmission control valve of a clutch hydraulic device according to an embodiment of the present invention. In FIG. 1, reference numeral 21 denotes a regulator for adjusting the pressure (clutch pressure) of the hydraulic oil discharged from the charging pump 1, and the hydraulic oil relieved from the regulator 21 is supplied to the torque converter 4. The hydraulic oil whose pressure has been adjusted by the regulator 21 passes through a modulating valve 22 and is supplied to a forward / reverse selection spool valve 23 via a throttle (W). (FWD) is supplied to the hydraulic clutch 11 and the reverse (REV) hydraulic clutch 12. It is also supplied to a spool valve (A) 24 and subsequently to a spool valve (B) 25. These spool valve (A) 24 and spool valve (B) 25
The first-speed (1ST) hydraulic clutch 13, the second-speed (2ND) hydraulic clutch 14, the third-speed (3
RD) hydraulic clutch 15, 4-speed (4TH) hydraulic clutch 16
Supplied to

Hydraulic oil is branched from the pressure oil inlet of the modulating valve 22 as control oil.
It is supplied to the lever type (manual) spool valve 28 of the forward / reverse selection spool valve 23, and the spool valve (A)
The solenoid valve (Bsol) 30 of the spool valve (B) 25 is supplied to the solenoid valve (Asol) 29 of 24.
Supplied to A forward selection solenoid valve (Fso) through a lever type (manual) spool valve 28
l) 31 and a reverse selection solenoid valve (Rsol) 32.

The solenoid valves 29, 30, 31, and 32 are operated in accordance with operation signals of clutch operation levers (forward / neutral / reverse / first speed / second speed / third speed / 4th speed). Forward / reverse selection spool valve 23, spool valve (A) 24, spool valve (B) so that hydraulic oil is supplied to each hydraulic clutch 11, 12, 13, 14, 15, 16 by exciting based on the operation diagram. 25, and a hydraulic circuit is configured.

As shown in detail in FIG. 3, a hydraulic pipe 41 for supplying hydraulic oil from the forward / reverse selection spool valve 23 to the forward hydraulic clutch 11 is branched into two, and one hydraulic pipe 41A is checked. A valve 42 is connected, a hydraulic pipe 43 is connected to the check valve 42, and the forward hydraulic clutch 11 is connected to the hydraulic pipe 43. Hydraulic piping 43
(Between the check valve 42 and the forward hydraulic clutch 11)
An accumulator 44 for accumulating a part of the hydraulic oil supplied to the hydraulic clutch 11 is provided. The other hydraulic pipe 41B is further branched into two and connected to the ports A and B of the forward control valve 45, and the port C of the forward control valve 45 is connected to the hydraulic pipe 23.

A hydraulic pipe 47 through which hydraulic oil is supplied from the forward / reverse selection spool valve 23 to the reverse hydraulic clutch 12 is
It is branched into two, one hydraulic pipe 47A is connected to the reverse hydraulic clutch 12, and the other hydraulic pipe 47B is connected to the port D of the forward control valve 45.

The forward control valve 45 is normally open between the port B and the port C. When hydraulic pressure is applied to the port A, the spool 52 moves against the spring 51 to move the spool 52 between the port B and the port C. When the oil pressure is lost and the oil pressure is lost, the spool 52 returns when the oil pressure is applied to the port D, and the spool 52 returns to open the port B and the port C again.

The operation of the configuration of the hydraulic circuit shown in FIG. 3 will be described. When shifting to the forward side, the hydraulic oil from the forward / reverse selection spool valve 23 is supplied to the forward side hydraulic clutch 11 while filling the accumulator 44 via the hydraulic piping 41, 41A, 43 and the check valve 42, and The pressure of the hydraulic clutch 11 is increased. Hydraulic oil is supplied to the port A of the control valve 45 through the hydraulic pipes 41 and 41B, so that the spool 52 moves against the spring 51 and the port B and the port C are shut off.
Thereby, the port C is closed, and the hydraulic piping 43 is closed.

In this state, when the gears are shifted by the speed-gear hydraulic clutches (first speed / 2nd speed / 3rd speed / 4th speed) 13-16,
As shown in FIG. 4, the hydraulic pressure of the hydraulic oil supplied to the forward hydraulic clutch 11 decreases instantaneously, but the hydraulic pressure of the forward hydraulic clutch 11 is reduced by the check valve 42 and the control valve.
The pressure is maintained by the action of the accumulator 44, which is blocked by the spool 52 of 45. Incidentally, the spring 51 is set to an appropriate small spring force so that the spool 52 does not return due to the instantaneous oil pressure drop.

When the speed is shifted to the reverse side, the hydraulic oil from the forward / reverse selection spool valve 23 is supplied to the reverse side hydraulic clutch 12 through the hydraulic pipes 47 and 47A, and the pressure of the reverse side hydraulic clutch 12 is increased. Also, the hydraulic fluid is supplied to the port D of the control valve 45 through the hydraulic pipes 47 and 47B. Therefore, when the hydraulic pressure is applied to the port D, the spool 52 returns, and the port B and the port C are opened again.
The hydraulic oil supplied to the motor 11 is returned to the forward / reverse selection spool valve 23 via the hydraulic pipe 43, the port B and the port C, and the pipes 41B and 41, and the hydraulic pressure of the forward hydraulic clutch 11 becomes zero.

According to the above-described operation, the forward gear is generated due to the instantaneous decrease in the hydraulic pressure of the hydraulic oil generated when the gears are shifted by the speed-stage hydraulic clutches (first speed / second speed / 3rd speed / 4th speed) 13-16. The hydraulic pressure of the side hydraulic clutch 11 is prevented from lowering, so that the slip of the forward hydraulic clutch 11 can be prevented, and a decrease in output shaft torque (torque loss) can be prevented.

As shown in detail in FIG. 5, a hydraulic pipe 61 for supplying hydraulic oil from the spool valve (B) 25 to the second speed hydraulic clutch 14 is branched into two, and one hydraulic pipe 61 is provided.
Check valve 62 is connected to A
A hydraulic pipe 63 is connected to 62, and the second-speed hydraulic clutch 14 is connected to the hydraulic pipe 63. An accumulator 64 that accumulates a part of the hydraulic oil supplied to the second-speed hydraulic clutch 14 is provided in the hydraulic pipe 63 (between the check valve 62 and the speed-stage hydraulic clutch).

The other hydraulic pipe 61B is branched into two, a hydraulic pipe 61C and a hydraulic pipe 61D. One hydraulic pipe 61C is connected to the port A of the control valve 71, and the other hydraulic pipe 61D is connected via a throttle 69. To the port B of the control valve 71. A hydraulic pipe 63 is connected to the port C of the control valve 71.

A hydraulic pipe 67 to which hydraulic oil is supplied from the control valve 22 is connected to a port D of the control valve 71.
It is connected to the. Control valve 71 is connected to port D
When the hydraulic oil is supplied from the modulating valve 22 and the hydraulic pressure applied to the port D becomes larger than the hydraulic pressure applied to the port A, the spool 72 moves against the spring 73. In the state where the hydraulic pressure applied to A is equal to or smaller than
Are shut off, and ports A and C are open respectively. When the hydraulic pressure applied to port D increases, spool 72 moves against spring 73 to allow communication between port C and port B. Has become. A holding means is formed by the accumulator 64, the control valve 71, and the like.

The same configuration as that shown in FIG. 5 is provided in a hydraulic pipe through which hydraulic oil is supplied to the third-speed hydraulic clutch 15. The operation of the configuration of the hydraulic circuit shown in FIG. 5 will be described.

When the clutch switching operation is performed to the second speed, the hydraulic oil from the spool valve (B) 25 is supplied to the hydraulic pipes 61, 61A,
Accumulator 64 via 63 and check valve 62
Is supplied to the second-speed hydraulic clutch 14 to increase the pressure of the second-speed hydraulic clutch 14. Also control valve 71
The inside is filled with hydraulic oil from port A via hydraulic piping 61B and from port C via hydraulic piping 63. Further, hydraulic oil is charged from the port D through the modulating valve 22.

In this state, when a shift to another speed stage (clutch switching) is performed, the hydraulic oil from the modulating valve 22 immediately returns to 0, and then the control valve 71 It is gradually supplied to port D.

The hydraulic pressure of the pipes 61, 61A, 61B, 61C, 61D, which has been supplying the hydraulic pressure to the second speed, communicates with the drain through the spool valve (B) 25, and quickly reaches 0 kg / cm ^2.
And attempts to disengage the second speed hydraulic clutch 14,
In the high-speed hydraulic clutch 14, a shelf-like hydraulic waveform Ps is obtained as the second-speed clutch hydraulic pressure Pa as shown in FIG. 6 by the set pressure of the accumulator 64 (for example, 10 kg / cm ² ).

Subsequently, when the clutch oil pressure Pb from the modulating valve 22 rises, the spool 72 of the control valve 71 moves gradually against the spring 73, and the port C and the port B are communicated.

Then, the hydraulic oil supplied to the second-speed hydraulic clutch 14 and the hydraulic oil filled in the accumulator 64 are supplied to the hydraulic pipe 63, between the port C and the port B, the pipe 61D,
Returned to the spool valve (B) 25 via 61B and 61,
The hydraulic pressure of the speed hydraulic clutch 14 becomes zero. At this time, as shown in FIG. 6, the release of the hydraulic oil from the second-speed hydraulic clutch 14 is suppressed by the throttle 69, so that the second-speed hydraulic clutch 14 is smoothly disengaged, so that power is transferred to another speed stage. And the change in output shaft torque also becomes smoother. When the throttle 69 is not provided, the hydraulic pressure of the second-speed hydraulic clutch 14 suddenly changes from the hydraulic pressure Ps to 0 as indicated by a two-dot chain line in FIG.
, The output shaft torque may be disturbed as indicated by a two-dot chain line.

According to the above-described operation, a decrease in the hydraulic pressure (existence of the time t in FIG. 11) generated when the gear shift is performed by the speed-stage hydraulic clutch can be eliminated, and the vehicle can be sufficiently operated even during the gear shift. A large torque. Further, by inserting the throttle 69 into the hydraulic pipe 61D for discharging the hydraulic oil of the clutch, torque disturbance can be prevented.

As shown in detail in FIG. 7, a hydraulic pipe 81 to which the hydraulic oil whose pressure is adjusted by the regulator 21 is supplied is connected to the inlet port A of the modulating valve 22. The hydraulic port 67, which is supplied to each of the spool valves 23, 24, 25 via a throttle (W), is connected to the outlet port B.

The valve (cylinder) 22 is separated by a spool 88 into a first oil chamber 83, a second oil chamber 89, and a third oil chamber 90. The second oil chamber 89 has an inlet port A and a port C. The port C is connected to a pilot port D via a hydraulic pipe 84, a throttle 85, and a hydraulic pipe 86, and the pilot port D communicates with the third oil chamber 90. The first oil chamber 83 communicates with the second oil chamber 89 through a small hole. Third oil chamber 90
The spool 87 is pushed by the spring 87 toward the first oil chamber 83 and the second oil chamber 89. Then, in a state where the clutch is connected and the first oil chamber 83 and the third oil chamber 90 are filled with the hydraulic oil whose pressure has been adjusted by the regulator 21, the hydraulic oil is supplied to the second oil chamber 89 at a clutch oil pressure of 100%. The position of the spool 88 is set so as to be supplied to each of the spool valves 23, 24, 25 via (the spring 87 is selected).

A duty solenoid valve 91 for guiding the hydraulic oil in the third oil chamber 90 to the drain is provided. The duty solenoid valve 91 is a two-position, two-port switching valve. The inlet port A is connected to the hydraulic piping 86, and the outlet port B is connected to the drain. The solenoid of the duty solenoid valve 91 is normally in a non-excited state and prevents the hydraulic oil in the third oil chamber 90 from being guided to the drain. However, when the solenoid is excited, the port A and the port A are disconnected. The port B communicates with the operating oil in the third oil chamber 90 to the drain. The modulating valve 22 and the duty solenoid valve 91 constitute a pressure adjusting means.

The operation of the modulation valve 22 and the duty solenoid valve 91 will be described. Now, with the combination of these valves 22 and 91, the clutch oil pressure at a duty ratio of 0% is set to 100% (for example, 25%).
kg / cm ² ) and the clutch oil pressure at a duty ratio of 100% is the minimum oil pressure determined by the strength of the spring 87 (for example, 1 kg / cm ² ). The duty ratio of 0 to about 15% is a dead zone of the hydraulic pressure and the hydraulic pressure remains at the maximum of 100%. Conversely, the dead pressure of about 85 to 100% remains at the minimum hydraulic pressure in the dead zone of the hydraulic pressure. When the clutch is connected, the hydraulic oil whose pressure has been adjusted by the regulator 21 passes through the modulating valve 22 and passes through the clutch oil pressure 100
% (The clutch oil pressure Pa before the shift in FIG. 8 is 100%) is supplied to the spool valves 23, 24, 25.

When the clutch is switched (shifted) (for example, when the change lever is changed from 2ND to 1ST), the duty ratio is changed from 0% to 75% as shown in FIG.
% To create a low oil pressure, for a short time 7
Retain 5%. Then, the clutch oil pressure Pb 'after the shift
Slightly increases and the clutch (eg, 2ND
When changing from 1ST to 1ST, the slip starts softly. At this time, the pre-shift clutch (2ND)
, A shelf-shaped hydraulic pressure Ps is formed by the hydraulic circuit shown in FIG.

Next, the duty ratio is rapidly decreased from 75% to 50%, and the clutch oil pressure Pb 'after shifting is held at the shelf hydraulic pressure Ps of the clutch before shifting (see FIG. 6). And suddenly rise to the force of the spring 73,
The shelf hydraulic pressure Ps of the pre-shift clutch is terminated. At this time, the clutch is in the slip state after the shift, but the clutch oil pressure Pb ′ has increased to the oil pressure Pr at which sufficient torque can be transmitted.

Next, the duty ratio is gently lowered from 50% to 40%, and the clutch oil pressure Pb 'is gently increased to connect the clutch gently to prevent the generation of shock torque.

Next, the duty ratio is suddenly decreased from 50% to 0%, and the clutch oil pressure Pb 'is sharply increased, thereby shortening the clutch oil pressure rising time. According to the above-described operation, by forming the pressure increasing waveform by the modulating valve 22 using the duty solenoid valve 91 for pilot pressure control, the time t until the clutch before shifting is disengaged.
₁ can be shortened, so that the time t 'from the start of the gear shift to the engagement of the clutch after the gear shift can be shortened, and the dead time of pressure increase after the clutch engagement can be eliminated. Further, there is no drive force loss, and a shift without shock can be performed.

As described above, the modulating valve 22
And the operation of the duty solenoid valve 91, the pressure increase waveform of the clutch hydraulic pressure can be arbitrarily formed. Therefore, when the operation of the clutch operation lever is determined, when starting and switching between forward and backward, as shown in FIG. Until the clutch is engaged, the pressure is quickly increased after the clutch is engaged, and the waveform shown in FIG. 8 is formed when the gear is shifted down and up.

With the above configuration, the following excellent effects can be obtained. First, in the start and forward / reverse switching, as shown in FIG. 9, a gradual increase hydraulic pressure waveform can be obtained for each speed stage until the clutch is engaged, and the pressure is quickly increased after the clutch is engaged. The maximum pressure can be reached faster than the waveform shown in FIG. 11, so that the time required for the clutch oil pressure to reach the maximum pressure can be shortened. be able to.

Further, downshifting of the speed stage (2ND → 1S)
T, 3RD → 2ND), shift up (2ND → 3R)
D, 3RD → 4TH) to prevent torque loss
You. At this time, a time t until the pre-shift clutch is disengaged.₁
Is determined by the rise time of the clutch after shifting {conventional time t₁
Was a long time (for example, 0.6 to 0.8 seconds).
After shifting, the clutch slips and the total time is t 'seconds
The rear shift is completed. Time t ₁If the gear is too long,
The feeling of shifting is impaired. Boost waveform
It can be arbitrarily formed (can be controlled)
From this, a waveform is created, for example, like Pb 'shown in FIG.
And the time t until the pre-shift clutch disengages.₁, Even if
Can be quickly switched to 0.2-0.3 seconds
And feel agile
You. Then, when the clutch slips after shifting, the conventional clutch
The inclination of the clutch is assumed to be the same as that of the latch hydraulic pressure waveform Pb.
Shock (engagement shock) at the end is also small as before
I can do it. After connecting, increase the hydraulic pressure quickly and
These loads increase after coupling and the clutch re-slip
This can prevent the driving feeling from being impaired.

[0051]

As described above, according to the present invention, it is possible to quickly increase the pressure of the hydraulic oil supplied to the hydraulic clutch after shifting, and the clutch re-slips to impair the driving feeling. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a transmission control valve of a clutch hydraulic device according to an embodiment of the present invention.

FIG. 2 is an operation diagram of a solenoid valve of a control valve of the clutch hydraulic device.

FIG. 3 is a hydraulic circuit diagram of a forward / reverse clutch in a control valve of the clutch hydraulic device.

FIG. 4 is a characteristic diagram of clutch hydraulic pressure and output shaft torque in the clutch hydraulic device.

FIG. 5 is a hydraulic circuit diagram of a second speed clutch in a control valve of the clutch hydraulic device.

FIG. 6 is a characteristic diagram of clutch hydraulic pressure and output shaft torque in the clutch hydraulic device.

FIG. 7 is a hydraulic circuit diagram of a modulation valve section in a control valve of the clutch hydraulic device.

FIG. 8 is a characteristic diagram of a clutch hydraulic pressure in the clutch hydraulic device.

FIG. 9 is a characteristic diagram of clutch hydraulic pressure in the clutch hydraulic device.

FIG. 10 is a hydraulic circuit diagram of a conventional transmission.

FIG. 11 is a characteristic diagram of clutch hydraulic pressure in a conventional transmission.

FIG. 12 is a characteristic diagram of clutch hydraulic pressure and output shaft torque in a conventional transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging pump 3 Transmission control valve 4 Torque converter 11 Forward hydraulic clutch 12 Reverse hydraulic clutch 13 First-speed hydraulic clutch 14 Second-speed hydraulic clutch 15 Third-speed hydraulic clutch 16 Four-speed hydraulic clutch 22 Modulation valves 23, 24, 25 Spool Valve 42, 62 Check valve 44, 64 Accumulator 45, 71 Control valve 69, 85 Throttle 91 Duty valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Eisei Nishimura 1-15-10, Kyomachibori, Nishi-ku, Osaka-shi, Osaka F-term in TCM Corporation (reference) 3J552 MA01 MA12 NA05 PA02 PA20 QA15A RA02 SA02 SA09 TB01 TB04 TB08 VA61W VA76W

Claims (5)

[Claims] 1. A clutch hydraulic device for selectively supplying oil to each hydraulic clutch of a transmission in response to an operation of a transmission change lever in an industrial vehicle using a torque converter, wherein the operation is supplied to a hydraulic clutch after shifting. A clutch hydraulic device comprising pressure adjusting means for arbitrarily forming an oil pressure rising waveform. 2. The clutch hydraulic device according to claim 1, wherein the pressure adjusting means rapidly increases the pressure of the hydraulic oil when the hydraulic clutch after the shift is connected by supplying the hydraulic oil. 3. The clutch hydraulic device according to claim 1, further comprising a holding unit that holds the hydraulic oil supplied to the hydraulic clutch before the shift for a certain period of time during a gear shift. 4. The pressure adjusting means reduces the hydraulic oil supplied to the hydraulic clutch before the shift, which is held by the holding means, in a short time when the hydraulic clutch is shifted down or up. The clutch hydraulic device according to claim 3, wherein 5. The clutch hydraulic device according to claim 1, wherein the pressure adjusting means is operated by operating a transmission change lever.