JPH0653262U - Shock absorber for switching in vehicle transmission - Google Patents

Abstract

(57) [Summary] [Purpose] Perform smooth shift switching at low speeds. [Structure] The engine EG speed and shift position are detected. When the engine speed is low, the solenoid 22 of the solenoid valve 20 is turned off. The master clutch boost valve 1 does not operate, and the master clutch MC remains connected. The transmission clutch is gradually increased in pressure,
Connected. The clutch is connected only once, and smooth shifting is performed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle transmission in which a master clutch is interposed between an output side of an engine and a pump blade of a torque converter, and a plurality of clutches are provided for a transmission, and particularly a mechanism for eliminating an impact when shifting is performed. Pertain to.

[0002]

[Prior art]

 In the conventional vehicle transmission of a wheel loader, the power from the engine is transmitted to the transmission via the torque converter, and after switching with multiple wet multi-plate clutches, the power is transmitted to the differential gear, final reduction gear, and tires. There is.

In such a mechanism, when a transmission clutch having a sufficient capacity is provided, the outer shape becomes large. For this reason, a master clutch is provided between the engine and the torque converter, and when connecting the transmission clutch, slide the master clutch so that the master clutch is connected after the connection. To reduce the size.

That is, as shown in FIG. 7, a master clutch MC, which is a wet multi-plate clutch, is interposed between the output side of the engine and the pump blade of the torque converter TC, and the wet multi-plate shift clutch is used for the transmission. It is provided with a plurality of speed stage clutches, namely a first speed clutch 1ST, a second speed clutch 2ND, a third speed clutch 3RD, a fourth speed clutch 4TH, a wet multi-plate forward clutch FWD and a wet multi-plate reverse clutch REV. A switching valve including a solenoid valve for arbitrarily switching the clutch 1ST, the second speed clutch 2ND, the third speed clutch 3RD, and the fourth speed clutch 4TH is connected.

In the figure, 1 is a master clutch pressure increasing valve, 2 is a transmission clutch pressure increasing valve, 3 is a flow sensing valve, 4 is a cutoff valve, 5 is an inching valve, 6 is a main pressure relief valve, and 7 is a cold relief. A valve, 8 is a strainer (70 Me), 9 is a pump, and 10 is an oil filter (10 μ).

[0006] In such a vehicle transmission, full modulation is performed in which a modulation action is exerted when switching between forward and backward and all speed stages. It also has an inching action that disengages the master clutch MC of the torque converter TC in conjunction with the braking action to shut off the power transmission from the engine.

The pressure oil sent by the pump 9 is adjusted to the clutch hydraulic pressure by the main pressure relief valve 6 and sent to the master clutch pressure increasing valve 1 and the transmission clutch pressure increasing valve 2. The hydraulic oil relieved by the main pressure relief valve 6 is sent to the torque converter TC.

The master clutch boost valve 1 is connected to the master clutch MC of the torque converter T C via an inching valve 5. The transmission clutch booster valve 2 is connected to the forward / reverse clutch switching valve and the speed-stage clutch switching valve.

The flow sensing valve 3 operates with a differential pressure before and after the throttle A, which is generated due to a decrease in the oil pressure in the clutch port associated with the operation of the change lever.

When the clutch switching operation is performed by the change lever, the flow sensing valve 3 operates against the biasing force of the spring due to the differential pressure before and after the throttle A, and the piston port of the transmission clutch pressure increasing valve 2 is drained. Guide to reduce the pressure in the clutch port.

Next, when the clutch port is filled with oil, the differential pressure before and after the throttle A disappears, the flow sensing valve 3 is returned by the urging force of the spring, and the pressure oil flows from the throttle B to the transmission clutch pressure increasing valve. Oil is sent to the 2nd piston port to smooth the oil pressure rise in the clutch port and reduce the shock when the clutch is engaged.

Further, the cut-off valve 4, like the flow sensing valve 3, operates by the biasing force of the spring at the same time as the clutch switching operation, and drains the piston port of the master clutch booster valve 1. Then, when the clutch hydraulic pressure exceeds the biasing force of the spring of the cutoff valve 4 during the process of connecting the transmission clutch, the cutoff valve 4 operates against the spring and restricts the piston ports C and D of the master clutch booster valve 1. The oil is sent from the oil to smooth the rise of the master clutch hydraulic pressure and reduce the shock when the master clutch is engaged.

As described above, the operation sequence of the booster valves is as follows: after the transmission clutch hydraulic pressure is increased by the transmission clutch pressure increasing valve 2, the cutoff valve 4 is activated and the master clutch pressure increasing valve 1 increases the master clutch hydraulic pressure. To act.

The inching valve 5 operates in conjunction with the service brake. That is, air pressure is supplied to the inching valve 5 by a hose from the air line of the brake valve.

When the brake pedal is depressed, compressed air is sent from the brake air line to the inching valve 5, and the inching valve 5 operates to drain the pressure oil in the master clutch MC and disconnect the master clutch MC. Therefore, the power transmission from the engine is temporarily cut off by the master clutch MC while the brake pedal is depressed.

The hydraulic waveform of the conventional vehicle transmission is set and constant under the most severe conditions for the transmission. Specifically, the switching between the second forward speed F2 and the second reverse speed R2 is set by a hydraulic waveform that does not burn the transmission clutch when the engine is at high idling (2200 rpm). Under this condition, the clutch does not burn, and as shown in Fig. 8, although the two clutches, the master clutch and the transmission clutch, are connected, the torque waveform has two steps, but there is a mountain. Since the distance between the toe and the mountain is narrow, a relatively good switching feeling can be obtained without experiencing a two-stage shock.

[0017]

[Problems to be solved by the device]

 However, under relatively light conditions for the transmission clutch, such as shift up / down or switching between forward and backward when the engine speed is low / medium speed (idling-1500 rpm), the transmission clutch engages at a low hydraulic pressure. As shown in FIG. 9, the gap between the peaks of the torque waveform becomes wide under the current condition of the hydraulic pressure waveform, so that a two-stage shock can be clearly felt and the switching feeling deteriorates.

The present invention has been made in view of the above circumstances and an object thereof is to provide a vehicle transmission that can eliminate a shock that occurs during a shift change.

[0019]

[Means for Solving the Problems]

 As shown in FIGS. 1 and 2, a master clutch MC is interposed between an engine EG and a torque converter TC, and a transmission TM is provided with forward and backward and transmission transmission clutches. A solenoid valve 20 is provided which is provided with a master clutch pressure increasing valve 1 and a transmission clutch pressure increasing valve 2 for controlling the hydraulic pressure of each clutch, and an electromagnetic valve 20 for adjusting the operating force of the master clutch pressure increasing valve 1, an engine speed and a shift position. A control unit 21 for turning on / off the solenoid valve 20 is provided in accordance with the above, and the control unit 21 includes a master clutch connecting / disconnecting means for turning on the solenoid valve 20 when the engine EG is rotating at a high speed during shift switching, and an electromagnetic solenoid in other cases. It is provided with a master clutch pressure holding means for turning off the valve 20.

As shown in FIGS. 4 and 5, a master clutch MC is interposed between an engine EG and a torque converter TC, and a transmission TM is provided with forward and backward and speed change transmission clutches. The proportional control valve 33,34 for increasing the pressure of the master clutch MC or the transmission clutch, and the controller 37 for driving and controlling the proportional control valve 33,34 according to the engine speed, the vehicle speed and the shift position. The control section 37 is provided with a high load shifting means for engaging and disengaging the master clutch MC and the transmission clutch at high speed and high engine speed during shift switching, and a transmission at low speed and low engine speed during shift switching. Provided with a low-load transmission that only engages and disengages the clutch. It has been confused.

[0021]

[Action]

 In the problem solving means according to claims 1 and 2, when the engine EG shifts under conditions severe for the capacity of the transmission clutch such as high rotation, the solenoid valve 20 is turned on, or the master clutch side proportional control valve 33 and The transmission side proportional control valve 34 is operated.

Then, the master clutch pressure decreases. After that, when the transmission clutch is boosted and connected, the master clutch boosting valve 1 or the master clutch side proportional control valve 33 is operated to gradually boost the master clutch MC and connect it.

On the other hand, when shifting the engine EG at a low speed or the like, the capacity of the transmission clutch is sufficient, so the solenoid valve 20 is left off, or only the transmission side proportional control valve 34 is operated.

In this case, with the master clutch MC still connected, only the transmission clutch is disengaged, only the transmission clutch slips, the clutch is connected only once, and a smooth shift change operation is possible.

[0025]

First Embodiment FIG. 1 is a hydraulic circuit diagram of a vehicle transmission showing a first embodiment of the present invention, FIG. 2 is an overall configuration diagram of the vehicle transmission, and FIG. 3 is a transmission clutch at the time of shifting. , A hydraulic pressure waveform and a torque waveform of the master clutch. The same components as those of the conventional one are designated by the same reference numerals.

As shown in FIGS. 1 and 2, the vehicle transmission according to the present embodiment includes a master clutch MC interposed between an engine EG and a torque converter TC, and a transmission TM including a forward / reverse and a transmission transmission clutch. It is provided with a master clutch pressure increasing valve 1 and a transmission clutch pressure increasing valve 2 for controlling the oil pressure of each clutch, and its hydraulic circuit is basically the same as that shown in FIG.

The shock absorber at the time of switching for eliminating the shock generated when switching between forward and reverse travels includes a solenoid valve 20 for adjusting the operating force of the master clutch booster valve 1, an engine speed and a shift position. A control unit 21 for turning on / off the solenoid valve 20 is provided accordingly.

The solenoid valve 20 is interposed between the piston port 1 a of the master clutch booster valve 1 and the cutoff valve 4. The solenoid valve 20 is of a two-position switching type. When the solenoid 22 is on, the cutoff valve 4 communicates with the piston port 1a at the A position, and when the solenoid 22 is off, the master clutch is at the B position. The intermediate point between the booster valve 1 and the inching valve 5 is communicated with the piston port 1a.

The control unit 21 is composed of a controller including a microcomputer, and has a function of detecting the switching position of the shift lever 23, a function of operating the solenoid of the clutch switching valve according to the switching position, and a shift switching operation. At times, the engine EG is provided with a master clutch disengagement function that turns on the solenoid valve 20 when the engine speed is high, and a master clutch pressure holding function that turns off the electromagnetic valve 20 otherwise. Since the method of detecting the rotation speed of the engine EG is well known, its description is omitted.

In the intermittent function, when the engine speed is 1500 rpm or more when switching between F2 and R2, or when the engine speed is 2000 rpm or more when switching between F1 and R1, The solenoid 22 of the solenoid valve 20 is turned on.

Further, in the master clutch pressure holding function, the solenoid 22 of the solenoid valve 20 is turned off when the engine speed at the time of upshift, downshift, or forward / reverse switching is lower than the above speed.

In the above structure, the master clutch MC is required under a severe condition for the transmission clutch such as switching between F2 and R2 (2200 rpm).

Therefore, when the forward / reverse movement is switched, the control unit 21 detects the shift position and the engine speed, analyzes the shift pattern, and determines the engine speed at the time of switching between F2 and R2. If it is 1500 rpm or more, or if the engine speed is 2000 rpm or more when switching between F1 and R1, the solenoid 22 of the solenoid valve 20 is turned on.

Then, the solenoid valve 20 is switched from the B position to the A position, and the piston port 1 a of the master clutch pressure increasing valve 1 is communicated with the cutoff valve 4. Therefore, the master clutch MC is gradually increased in pressure via the master clutch pressure increasing valve 1 by operating the cutoff valve 4 after the pressure in the transmission clutch is increased. At this time, the shock at the time of switching is small as in the conventional case.

On the other hand, it is not necessary under relatively light conditions for the transmission clutch such as switching between F2 and R2 (1500 rpm) and shift up / down, and only the transmission clutch is slipped, modulated and the clutch is engaged. It reduces the shock of time.

That is, in the control unit, the solenoid valve 20 is kept in the solenoid OFF state from the engine speed and the shift position, and the same hydraulic pressure as the supply pressure to the master clutch MC is applied to the piston port 1a of the master clutch booster valve 1. To supply.

At this time, the hydraulic pressure of the master clutch MC does not change and the transmission clutch is boosted as usual, so only the transmission clutch slips and the torque waveform has one peak as shown in FIG. The double shock is eliminated.

Therefore, since the disengagement of the master clutch is switched according to the situation at the time of shift switching, the switching shock does not occur even when the forward / reverse switching is performed when the engine EG is at low rotation, and a smooth gear shift is performed. Switching operation becomes possible.

Second Embodiment FIG. 4 is a schematic configuration diagram of a vehicle transmission showing a second embodiment of the present invention, FIG. 5 is a control block diagram of the vehicle transmission, and FIG. 6 is a flowchart at the time of shifting.

In the vehicle transmission of this embodiment, a master clutch MC is interposed between an engine EG and a torque converter TC, and a transmission TM is provided with forward and backward and transmission transmission clutches. Power is transmitted to the tire 32 through the lenticular gear 30 and the final reduction gear 31.

Then, the respective proportional control valves 33 and 34 for increasing the pressure of the master clutch MC or the transmission clutch, the engine rotation detecting section 35, the vehicle speed detecting section 36, the engine speed, the vehicle speed and the shift position. A control unit 37 for driving and controlling the proportional control valves 33, 34 is provided in accordance with the above.

The proportional control valves 33, 34 gradually increase the clutch pressure in order to prevent a shock when connecting each clutch, and are used in place of the respective pressure increasing valves in the first embodiment, and are used as control units. It is activated by a control signal from 37.

The control unit 37 is composed of a controller equipped with a microcomputer and the like, has a function of detecting the shift position of the shift lever, a high speed (10 km / h or more) and a high engine speed (1500 rpm or more) at the time of shift switching. High load shifting function that operates both proportional control valves 33 and 34 to engage and disengage master clutch MC and transmission clutch, and low speed (less than 10 km / h) and low engine speed (less than 1500 rpm) when shifting gears only transmission clutch It is provided with a low load variable speed function that operates only the transmission side proportional control valve 34 so as to be intermittent. Since the method of detecting the rotation speed of the engine EG and the method of detecting the vehicle speed are well known, the description thereof will be omitted.

In the above configuration, when the shift lever position is switched to change gears, this operation signal is input to the control unit 37. Then, the engine speed detection unit 35 and the vehicle speed detection unit 36 respectively input signals of engine speed and vehicle speed to the control unit 37, and based on these signals, the control unit 37 performs calculation and judgment.

When the vehicle speed is high and the engine speed is high, the capacity of the transmission clutch is insufficient, so the master clutch side proportional control valve 33 is first actuated and the master clutch MC is temporarily disengaged. Then, the transmission side proportional control valve 34 is operated to gradually increase the pressure of the transmission clutch and connect it. After that, the master clutch side proportional control valve 33 is operated to gradually increase the pressure of the master clutch M C and connect it.

When the vehicle speed is high and the engine speed is low, or when the vehicle speed is low, for example, when the power of the engine EG is small or the vehicle starts from a stationary state, the capacity of the transmission clutch is sufficient. With the master clutch MC kept connected, only the transmission side proportional control valve 34 is operated to connect the transmission clutch. This allows the clutch to be connected only once, reducing the shock at the time of gear shifting and enabling smooth gear shifting operation.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention.

For example, in the first embodiment, the engagement / disengagement of the master clutch may be controlled not only when switching between forward and reverse, but also when switching at a speed stage where the gear ratio greatly differs.

[0049]

[Effect of device]

 As is clear from the above description, according to claims 1 and 2 of the present invention, it is possible to select the on / off state of the master clutch by controlling the operation of the solenoid valve or the proportional control valve according to the situation at the time of shift switching. Therefore, when the transmission clutch capacity such as low engine speed is sufficient, the master clutch can be left connected and the transmission clutch can be connected. Therefore, it is only necessary to connect the clutch twice, and it is possible to reduce the shock at the time of shifting and to achieve a smooth shifting operation. .

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a vehicle transmission showing a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a vehicle transmission device

FIG. 3 is a hydraulic pressure waveform and a torque waveform of a transmission clutch and a master clutch at the time of shift switching in the case of low engine speed.

FIG. 4 is a schematic configuration diagram of a vehicle transmission showing a second embodiment of the present invention.

FIG. 5 is a control block diagram of the vehicle transmission.

FIG. 6 is a flowchart when shifting gears.

FIG. 7 is a hydraulic circuit diagram of a conventional vehicle transmission.

FIG. 8 is a hydraulic pressure waveform and a torque waveform of the transmission clutch and the master clutch at the time of shift switching in the case of high engine speed.

FIG. 9 is a hydraulic pressure waveform and a torque waveform of a transmission clutch and a master clutch at the time of shift switching in the case of low engine speed.

[Explanation of symbols]

 EG engine TC torque converter MC master clutch TM transmission 1 master clutch booster valve 2 transmission clutch booster valve 3 flow sensing valve 4 cutoff valve 20 solenoid valve 21 control unit 22 solenoids 33, 34 proportional control valve 35 engine rotation detection unit 36 vehicle speed detection Part 37 Control unit

Continued Front Page (72) Hiroyuki Yokoyama, 1-15-10 Kyomachibori, Nishi-ku, Osaka-shi, Osaka Toyo Transporter Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A master clutch pressure-increasing valve and a transmission clutch pressure-increasing valve, wherein a master clutch is interposed between an engine and a torque converter, a transmission is provided with forward and backward and transmission transmission clutches, and the hydraulic pressure of each clutch is controlled. In the vehicle transmission equipped with, a solenoid valve for adjusting the operating force of the master clutch booster valve, and a control unit for turning on and off the solenoid valve according to the engine speed and the shift position are provided.
The control unit is provided with a master clutch connecting / disconnecting means for turning on the solenoid valve when the engine is rotating at a high speed during shift switching, and a master clutch pressure holding means for turning off the solenoid valve in other cases than the above. Shock absorber at the time of switching in the transmission. 2. A vehicle transmission in which a master clutch is interposed between an engine and a torque converter, and the transmission is provided with forward and backward and transmission transmission clutches, a proportional ratio for boosting the master clutch or the transmission clutch. A control valve and a control unit that drives and controls the proportional control valve according to the engine speed, the vehicle speed, and the shift position are provided.
The control unit has a high-load shifting means that engages and disengages the master clutch and the transmission clutch at the time of shift switching at high speed and high engine speed, and a low-load shifting that disengages only the transmission clutch at the time of shift switching at low speed and low engine speed. And a shock absorbing device at the time of shifting in a vehicle transmission.