JP2877274B2 - Transmission hydraulic control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pressure control system for controlling the engagement of a friction engagement element mounted on a plurality of sets of planetary gear mechanisms with an input shaft end directly connected to an output shaft of an engine. The present invention relates to a hydraulic control device for a direct power shift transmission, which achieves a desired shift speed by selectively performing the shift speed through a transmission.

[0002]

2. Description of the Related Art Construction machines such as motor graders, self-propelled scrapers (motor scrapers), bulldozers, wheeled tractor excavators (wheel loaders), and industrial vehicles such as forklift trucks and straddle carriers, which are cargo handling machines. Transmissions need to cover a shift range from an extremely low speed range for the original work to a normal traveling speed for traveling on a general road, so that the speed range of 6 to 8 speeds is generally increased or decreased. Have both.

[0003] Since the transmission mounted on the above-mentioned construction earth-moving machine or industrial vehicle has an extremely large number of shift speeds, the transmission is designed to be compact and easy to shift.
A direct power shift transmission disclosed in Japanese Patent Application Laid-Open No. 62-255621 (hereinafter referred to as D
PS). This DPS is composed of a plurality of sets of planetary gear mechanisms whose input shaft ends are directly connected to the output shaft of the engine without passing through a fluid coupling such as a torque converter. By electrically controlling the selective supply and discharge of pressure oil to these friction engagement elements,
An arbitrary rotating element of the planetary gear mechanism is connected to the transmission input shaft or fixed to the transmission casing, and the gear ratio corresponding to the gear position of the transmission lever selected based on the driver's operation. Is switched.

As shown in FIG. 18 showing the concept of a hydraulic control circuit in such a conventional DPS, an oil passage 102 for guiding pressure oil from an oil pump 101 has a plurality of friction engagement elements for shifting ( Brake 103, 104, 105, 10
6 is connected to a directional control valve 107 for controlling the supply and discharge of pressure oil to and from an oil passage 108 to which the pressure oil from the oil pump 101 is supplied via the directional control valve 107. A forward / reverse switching valve 111 for switching between supply and discharge of pressure oil is connected to two clutches 109 and 110, which are friction engagement elements for forward and reverse travel, respectively, through a pressure reducing valve 112.

[0005] The pressure reducing valve 112 is used to alleviate a shock generated at the time of gear shifting by delaying the engagement timing with the clutches 109 and 110 from the engagement timing of the brakes 103 to 106. The hydraulic oil is temporarily drained from the engaged one of the two clutches 109 and 110, and in this state, the selective supply and discharge of hydraulic pressure to and from the brakes 103 to 106 are performed. Is supplied again to the two clutches 109 and 110 via the pressure reducing valve 112 to return to the original state.

[0006]

In the conventional DPS shown in FIG. 18, the pressure oil is temporarily drained from the engaged one of the two clutches 109 and 110 during the gear shifting operation, and then the oil passage 10 is moved.
8, the low-pressure oil is supplied again to the two clutches 109 and 110 via the pressure reducing valve 112, and the clutches 109 and 11 are temporarily released because they are returned to the original engaged state.
It takes time to return 0 to the engaged state again. As a result, there is a disadvantage that the time from the start to the end of the shift increases and the shift feeling is not so good.

[0007]

SUMMARY OF THE INVENTION The present invention is based on the above-described knowledge, and completes a shift operation within a short time without causing a shift shock.
It is an object of the present invention to provide a hydraulic control device of S.

[0008]

SUMMARY OF THE INVENTION A DPS hydraulic control apparatus according to the present invention comprises a planetary gear mechanism for forward and backward movement in which an input shaft end is directly connected to an output shaft of an engine, and a planetary gear mechanism for forward and backward movement. Two forward and backward frictional engagement elements assembled to the rotating element constituting the rotating element, a plurality of speed change planetary gear mechanisms connected to the forward / reverse planetary gear mechanism, and a speed change planet. A plurality of speed-change friction engagement elements assembled to the rotating elements constituting the gear mechanism; and a supply oil pressure for the forward and reverse friction engagement elements that is greater than a supply oil pressure for the speed-change friction engagement elements. In a direct power shift transmission including a pressure reducing valve for reducing pressure and an electronic control unit capable of controlling the supply and discharge of pressure oil selectively to these friction engagement elements to achieve a predetermined gear position, Temporarily bypassing the pressure reducing valve
Non-depressurized pressure oil is directly applied to the forward and backward friction
A bypass valve for supplying the
When the valve is opened, the pressure regulating function of the pressure reducing valve is forcibly stopped.
It is characterized in that it is stopped .

[0009]

When the shift operation is started, the hydraulic oil is temporarily drained from the engaged one of the forward and reverse frictional engagement elements based on a command from the electronic control unit. Selective supply and discharge of hydraulic pressure to and from the friction engagement element is performed.

At the same time, the pressure oil, which has been temporarily drained, is temporarily supplied directly from the bypass valve to the forward and reverse frictional engagement elements without passing through the pressure reducing valve.
Pressure oil in forward and reverse frictional engagement without decompression
Is supplied to the element side, large quantities subjected the gap filling frictional engagement element
This is done quickly with the supplied pressure oil . Then, from this state, the pressure oil in the depressurized state is again supplied to the forward and reverse friction engagement elements via the pressure reducing valve, and smoothly returns to the original engaged state to complete the gear shifting operation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1 showing the concept of a control system and FIG. 2 showing the concept of a drive system in one embodiment, the hydraulic control system for a DPS according to the present invention is incorporated in a motor grader and has eight stages in both forward and backward directions. The transmission input shaft 14 connected to the crankshaft 12 of the engine 11 via a damper 13 is provided with a reverse sun gear 15 and a forward sun gear 16 integrally therewith. A reverse clutch 20 is interposed between the reverse planet carrier 18 meshing with the reverse planet carrier 18 and the transmission case 19. The forward planetary carrier 22 of the forward planetary gear 21 meshing with the forward sun gear 16 has a reverse planetary gear 1.
The reverse internal gear 23 and the drive gear 24 meshing with the gear 7 are integrally provided. Further, a forward clutch 26 is interposed between the transmission case 19 and the forward internal gear 25 meshing with the forward planetary gear 21.

A fourth planetary carrier 29 integrally provided with an input gear 28 meshing with the drive gear 24 via a transmission gear group 27 has a fourth planetary gear 31 meshed with a fourth sun gear 31 provided on an intermediate shaft 30. Planetary gear 32 and third planetary gear 3
The transmission case 19 has a 4.8 speed brake 35 interposed between a fourth internal gear 34 meshing with the fourth planetary gear 32 and the transmission case 19. The third planetary gear 33 meshes with a third sun gear 36 provided on the intermediate shaft 30 adjacent to the fourth sun gear 31 and a third internal gear 37 surrounding the third planetary gear 33. And the third internal gear 37 and the transmission case 1
The 9th and 9th are interposed a 3.7-speed brake 38. The second planetary carrier 39 integrally formed with the third internal gear 37 has a second planetary gear meshing with a second sun gear 40 provided on the intermediate shaft 30 adjacent to the third sun gear 36. A gear 41 is rotatably provided. Between the second internal gear 42 surrounding the second planetary gear 41 and meshing with the second planetary gear 41 and the transmission case 19, there is provided a gear 2.
-A 6-speed brake 43 is interposed. Further, the first planetary carrier 44 in which the second internal gear 42 is integrally formed.
A first planetary gear 46 meshing with a first sun gear 45 provided on the intermediate shaft 30 adjacent to the second sun gear 40
Is provided rotatably, and surrounds the first planetary gear 46 and meshes with the first planetary gear 46.
7 between the transmission case 19 and the 1.5-speed brake 4
8 are interposed.

On the other hand, a transmission output shaft 50 integrally formed with an output bevel gear 49 has a high-low switching planet carrier 51.
The height-changing planetary carrier 51 is provided with an elevation-changing planetary gear 53 that meshes with an elevation-changing sun gear 52 provided on the intermediate shaft 30 adjacent to the first sun gear 45. It is rotatably mounted. or,
A low-speed brake 55 is interposed between the transmission case 19 and the internal gear 54 for high / low switching which surrounds the planetary gear 53 for high / low switching and meshes with the planetary gear 53 for high / low switching. Switching planet carrier 51 and intermediate shaft 30
And a high-speed brake 56 is interposed therebetween.

Each of the clutches 20, which are friction engagement elements,
26 and brakes 35, 38, 43, 48, 55, 56
Each of them is constituted by a hydraulic device provided with an engagement piston device, a servo device, and the like. These engagement states are determined by a pump driving gear 57 provided at the distal end of the transmission input shaft 14.
The pressure is switched via a hydraulic control device 60 described later by hydraulic oil supplied from an oil pump 59 having a transmission gear 58 that meshes with the transmission gear 58. In this case, in this embodiment, based on the selected position of the forward / reverse switching lever 61 provided in the cabin (not shown), the position of the shift lever 62, and the driving state of the vehicle,
The engagement states of the clutches 20, 26 and the brakes 35, 38, 43, 48, 55, 56 are switched by a command from the electronic control unit 63 for controlling the operation state of the engine 11, and a predetermined gear position is achieved. It has become so.

That is, when a gear shift operation is performed, the hydraulic pressure of the hydraulic oil supplied to the reverse clutch 20 or the forward clutch 26 is temporarily reduced, whereby the drive gear 24 from the crankshaft 12 of the engine 11 is reduced. Transmission of driving force to the brakes, and then brakes 35, 38, 43, 48, 5
After performing a desired brake engagement operation and a release operation of 5,56 to achieve a predetermined shift speed, supply hydraulic pressure to the reverse clutch 20 or the forward clutch 26 is restarted, and the engine 11 The rotation of the crankshaft 12 is gradually transmitted to the transmission output shaft 50.

For this reason, an electronic control unit (hereinafter referred to as an ECU) 63 includes a detection signal from a forward / reverse switch 64 for detecting the position of the forward / reverse switching lever 61 and a signal from the engine 11. A detection signal from an engine rotation speed sensor 65 that detects the rotation speed of the crankshaft 12;
A detection signal from a transfer rotation speed sensor 66 for detecting the rotation speed of the drive gear 24, a detection signal from a vehicle speed sensor 67 for detecting the rotation speed of the transmission output shaft 50 corresponding to the running speed of the vehicle, and a shift lever 62 The detection signal from the shift position sensor 68 for detecting the position of the accelerator pedal and the accelerator opening sensor 7 for detecting the opening of the accelerator pedal 69
A detection signal from 0 is input.

As shown in FIG. 3 showing a select pattern of the shift lever 62 in this embodiment, P (parking), N (neutral), D
(1st to 8th speed automatic shifting), 5 (1st to 6th speed automatic shifting), 3
In addition to (first-speed to fourth-speed automatic shifting), two shifting positions, UP for upshifting by manual operation and DW for downshifting, are set on the left and right sides of the D range.

A shift mode changeover switch 71 for switching between an automatic shift mode and a manual shift mode is attached to the upper end of the shift lever 62. The shift mode changeover switch 71 connected to the ECU 63 is pressed once. The shift mode is switched, and the original shift mode is selected by pressing twice. When the shift mode changeover switch 71 is operated to select the manual shift mode, the shift lever 62 is shifted to the UP position or the DW position in the D range, thereby upshifting and downshifting the current shift speed. The shift and the shift can be freely switched. However, when the automatic shift mode is selected by operating the shift mode changeover switch 71, even if the shift lever 62 is shifted to the UP position or the DW position, the upshift or the downshift is not performed and the D range 1 The first to eighth speed automatic shifting is maintained.

The shift lever 6 in this embodiment as described above.
As shown in FIG. 4 showing the cross-sectional structure of FIG. 2 and FIG. 5 showing the cross-sectional structure taken along the line VV, a manual transmission pivot 73 is integrally joined to the sensor bracket 72 to which the shift position sensor 68 is attached. This manual transmission pivot 73
Are rotatably attached to the lower ends of a pair of front and rear pivot support brackets 74 and 75 provided in a cabin (not shown). And the shift lever 6
2 is located in the D range, the shift lever 6
2 is a manual transmission pivot 7 corresponding to the UP position and the DW position.
3 can be swung right and left.

The lower end of the shift lever 62 is connected to a shift position sensor 6 orthogonal to a manual shift pivot 73.
The rotary shaft 76 is integrally connected to the rotary shaft 76, and five turning positions P, N, D, 5, and 3 can be selected back and forth around the rotary shaft 76. For this reason, an opening 79 is formed in the upper plate 78 of the transmission lever case 77 that guides the movement of the transmission lever 62 by bending an intermediate portion connecting the N range and the D range at a right angle as shown in FIG. , D range, an opening 80 corresponding to the UP position and the DW position is formed so as to be orthogonal to the opening.

Immediately below the manual transmission pivot 73, the reference position of the transmission lever 62 in the D range, that is, the opening 7
A reference position sensor 81 for detecting that the shift lever 62 is located at the position where the 9, 80 crosses is fixed. Further, on the left and right sides of the reference position sensor 81, the UP position of the shift lever 62 in the D range and An upshift switch 82 and a downshift switch 83 for respectively detecting the DW position are fixed. Further, both ends of a left and right spring support arm 84 integrally fixed to the rear end of the manual transmission pivot 73 and the pivot support bracket 75 on the rear end side.
Are connected to each other via a pair of left and right extension coil springs 85.

Therefore, when the shift lever 62 is in the D range, the shift lever 62 is always held at the above-mentioned reference position when the driver does not apply any force to the shift lever 62. I have. When the driver operates the shift lever 62 to either the UP position or the DW position, the left and right ends of the base plate 86 integrated with the sensor bracket 71 are either the upshift switch 82 or the downshift switch 83. Irrespective of the operation of the shift mode changeover switch 71, the one-step upshift signal or the downshift signal
3 is output. When the driver repeats this operation a plurality of times, a multi-stage upshift signal or downshift signal can be arbitrarily output.

In this embodiment, a forward / reverse switching lever 61 incorporating a forward / reverse switching switch 64 is provided on the side of the transmission lever 62, and accordingly, the upper plate 77 of the transmission lever case 76 is provided. Is a forward / reverse switching lever 61
An opening 87 is formed to guide the forward / backward movement of the forward / backward movement, and the position of the forward / backward switching lever 61 is set to F (forward), N (neutral), R
By selecting any one of (reverse), the traveling direction of the vehicle can be switched back and forth.

In this manner, the driver operates the forward / reverse switching lever 61 for switching the forward / backward movement of the vehicle, and selects the forward or backward traveling direction of the vehicle. By selecting one of the three ranges, it is possible to switch to a predetermined forward gear or a reverse gear. The clutches 20, 26 and the brakes 35, 38, 43, 48,
The way in which 55 and 56 work is as shown in FIG. 6, where the symbol ○ in the figure indicates that the clutch is engaged by hydraulic operation.

In this embodiment, when the vehicle is parked by holding the shift lever 62 in the P range, mechanical braking of the drive system is performed in conjunction with the operation of the shift lever 62. A mechanical hydraulic brake 88 whose engagement state is switched via an actuator (not shown) that is interlocked with the operation of 62 is interposed between the planet carrier 51 for level switching and the transmission case 19. An actuator for switching the engagement state of the mechanical hydraulic brake 88 includes:
The operation of the shift lever 62 is interlocked with the hydraulic control device 60 independently.

In order to achieve the gears shown in FIG. 6 described above, the transmission case 19 has a hydraulic pressure for controlling the supply and discharge of pressure oil to and from the clutches 20, 26 and the brakes 35, 38, 43, 48, 55, 56. The control device 60 is assembled.
As shown in FIGS. 7 and 8 showing a schematic structure of a main part of the hydraulic control device 60 according to the present embodiment, the hydraulic control device 60 according to the present embodiment is configured to pump the pressure oil sucked up from the oil reservoir 601 by the oil pump 59. The clutches 20, 26 and the brakes 35, 38, 43, 48, 55, 56 are selectively supplied or recovered to piston devices or servo devices (not shown) in accordance with the operating state of the vehicle.
26 and the brakes 35, 38, 43, 48, 55, 56 for selectively engaging or disengaging them.
No. 621, which is well known. Therefore, it is of course possible to employ a hydraulic control device having a configuration other than the present embodiment described below.

That is, in the middle of an oil passage 603 connecting the oil pump 59 and the sequence valve 602, the oil pressure in the oil passage 603 is set to a predetermined desired value (hereinafter, referred to as a high line pressure). A relief valve 604 to be adjusted below is connected via a pressure adjusting oil passage 605.

Main line oil passage 606 and main pilot oil passage 607
The sequence valve 602 is connected to the main line oil passage 606 to supply the high line pressure supplied from the oil passage 603 to the main pilot oil passage 607 prior to the main line oil passage 606. Is connected to a pressure control valve 608 and a later-described bypass valve 610 incorporating a non-energized closing type solenoid valve 609 for bypass. The high line oil passage 611 communicating with the main line oil passage 606 via the pressure control valve 608 has a high-speed / low-speed switching in which a neutral solenoid valve 612 and a low-speed solenoid valve 613 are respectively closed when not energized. A valve 614 is connected, and a pressure reducing valve 615 is interposed in the middle of the high line oil passage 611.

An inching valve 617 connected to the pressure reducing valve 615 via a low line oil passage 616 is provided in the clutches 20, 26 in accordance with the depression amount of an inching pedal 89 (see FIG. 1) which is depressed by the driver's operation. The pressure oil in the engaged state can be reduced to realize a so-called half-clutch state of the engine 11, and the pressure reducing valve 615 reduces the pressure oil supplied from the high line oil passage 611 side to the high oil pressure. The line pressure is adjusted to a predetermined desired value (hereinafter, referred to as a low line pressure) and supplied to the low line oil passage 616 side. In other words, the pressure reducing valve 615 supplies hydraulic oil having a lower pressure than the brakes 35, 38, 43, 48, 55, 56 to the clutches 20, 26, and the engagement timing of the clutches 20, 26 at the time of shifting is braked. 35,38,4
The shift timing is forcibly delayed from the engagement timings of 3, 48, 55, and 56 to reduce shift shock.

A forward / reverse switching valve 619 that controls the supply and discharge of pressure oil to and from the two clutches 20 and 26 that achieve the forward speed or the reverse speed, respectively, and that incorporates a non-energized closed type reverse solenoid valve 618. And the inching valve 617 is connected to an oil passage 620.
The ECU 63 also receives a detection signal from an inching opening detection sensor 90 that detects the opening of the inching pedal 89. Further, the middle of the oil passage 620 and the bypass valve 610 are connected via a bypass oil passage 621.

The two brakes 3 for achieving the third, seventh or first and fifth gear stages respectively in the middle of the high line oil passage 611 between the pressure reducing valve 615 and the high / low speed switching valve 614.
The 1.5-speed-3.5-th control valve controls the supply and discharge of pressure oil to 8,48 and incorporates a 3,7-speed solenoid valve 622 and a 1.5-speed solenoid valve 623 which are closed when not energized. The seven-speed switching valve 624 communicates with each other via a branch high-line oil passage 625, and in the middle of the branch high-line oil passage 625, a fourth-speed / eight-speed or a second-speed / sixth-speed gear stage is provided. Control of the supply and discharge of pressure oil to and from the two brakes 35 and 43, respectively, and the non-energized closed 4/8 speed solenoid valves 626 and 2.6
2-, 6-, 4- and 8-speed switching valve 6 incorporating a speed solenoid valve 627
28 are interposed.

These high / low speed switching valves 614, 1.5 / 5 speed-3
The 7-speed switching valve 624, the 2-6-speed-4 / 8-speed switching valve 628 are all three-position switching valves in which the neutral position is set,
Pressure oil from the main pilot oil passage 607 acts on both sides of these spools (not shown), and by selectively energizing the solenoid valves 612, 613, 622, 623, 626, 627 for shifting, these spools are shifted from the neutral position. The supply and discharge of the high line pressure from the high line oil passage 611 and the branch high line oil passage 625 to the brakes 35, 38, 43, 48, 55, 56 can be switched.

Each of the speed-changing solenoid valves 612, 613, 62
FIG. 9 shows the relationship between the energized state of the solenoids 2,623,626,627 and the reverse electromagnetic valve 618 and the respective shift speeds. The symbol in the figure indicates that these electromagnetic valves 612,613,618,622,623,626,627 are energized, respectively.

As shown in FIGS. 10 and 11 showing an enlarged sectional structure of a portion of the inching valve 617 in this embodiment,
An inlet port 629 communicating with the upstream low-line oil passage 616;
A control spool 632 and a cylindrical shape are provided on a valve body 631 in which an outlet port 630 communicating with the oil passage 620 on the downstream side and two oil discharge ports EX ₁ and EX ₂ connected to the oil reservoir 601 are formed. are slidably fitted in the inching spool 633 forming a can, annular groove communicating either or an outlet port 630 and the oil discharge port EX ₂ communicates the inlet port 629 and outlet port 630 on the outer peripheral surface 634 The inner spool 635 is slidably fitted in the inching spool 633 in which is formed.

The control oil chamber 636, which is partitioned by the valve body 631 and one end face (the left end face in the figure) of the control spool 632, enters the control oil chamber 636 from the middle of the main line oil passage 606 through which high line pressure hydraulic oil flows. The branch control oil passage 637 communicates with the orifice 6
In the middle of the control oil passage 637 provided with 38, the control oil passage 637 corresponds to the depression amount of the inching pedal 89.
A non-energized closing type inching solenoid valve 639 capable of lowering the oil pressure in the inside is provided. In this embodiment, the duty ratio of the energization amount to the inching solenoid valve 639 is increased in proportion to the depression amount of the inching pedal 89, and the duty ratio of the energization amount to the inching solenoid valve 639 and the oil passage The relationship with the hydraulic pressure supplied to the clutches 20, 26 has characteristics as shown in FIG.

For this reason, the outer peripheral surface has one oil discharge port EX ₁
A compression coil spring 640 having a spring force smaller than the high line pressure is interposed between the control spool 632 facing one end of the inching spool 633 and the other end of the valve body 631 (in the figure, A compression coil spring 641 for biasing the inner spool 635 to the other end surface of the control spool 632 is also interposed between the right side) and the inner spool 635. In the center of the inner spool 635, there is formed an oil hole 643 facing the pressure regulating oil chamber 642 surrounded by the other end of the valve body 631 and the other end of the inching spool 633. This is on one end of the oil hole 643 oil discharge oil opening 645 that may communicate with the oil discharge port EX ₂ through the oil hole 644 formed at one end of the inching spool 633 is formed, also, the oil holes Inching spool 6 in the middle of 643
An adjusting oil hole 647 that can communicate with the inlet port 629 or the outlet port 630 is formed through an oil hole 646 that faces an annular groove 634 formed in the center of 33.

Accordingly, when the inching solenoid valve 639 is in a non-energized state, the high line pressure remains unchanged from the control oil passage 637 to the control oil chamber 6.
10, the control spool 632 is urged to the right side of the valve body 631 together with the inching spool 633 as shown in FIG.
Is biased toward the other end surface of the control spool 632 by the spring force. As a result, the upstream low line oil passage
The inlet port 629 connected to the oil passage 616 and the outlet port 630 connected to the oil passage 620 on the downstream side are in communication with each other through the annular groove 634. The oil is supplied to the clutches 20 and 26 via the advance switching valve 619, while the oil pressure in the pressure adjusting oil chamber 642 is set to the oil hole 643 and the oil drain hole 645,
Through the oil hole 644 in a state of communicating with the oil discharge port EX _2.

In this state, when the driver depresses the inching pedal 89 slightly, the inching opening sensor 90 detects the opening and supplies a corresponding amount of duty ratio power to the inching solenoid valve 639 from the ECU 63. And
The pressure oil in the control oil passage 637 downstream of the orifice 638 is discharged, and the oil pressure in the control oil chamber 636 decreases. Then, due to the spring force of the compression coil springs 640 and 641, the inner spool 6
The control spool 632 and the inner spool 635 move until the annular spring receiving portion 648 formed on the other end of the abutment 35 contacts the step 649 formed on the inner peripheral surface of the inching spool 633. As a result, the pressure regulating oil chamber 642 has the oil hole 643 and the adjusting oil hole 64.
7, the line is communicated with the inlet port 629 through the oil hole 646, and the low line pressure is also supplied to the pressure regulating oil chamber 642, but the description so far is the state of the region ab in FIG. .

From here, when the inching pedal 89 is further depressed, the pressure applied to the other end surface of the inner spool 635 becomes higher than the pressure applied to one end surface of the control spool 632. In accordance with the pressure balance, the inching spool 633 also moves as shown in FIG. 11, so that the areas c to d in FIG. 12 are achieved. As a result, the inching spool 633 becomes capable of closing the inlet port 629 in response to the change in the amount of depression of the inching pedal 89, and at the same time, the outlet port 630 and the oil discharge port via the annular groove 634.
EX ₂ can be communicated, and by further depressing the inching pedal 89 from the state shown in FIG. 11,
The pressure oil supplied to the clutches 20 and 26 is discharged through the forward / reverse switching valve 619 and the oil passage 620. In this way, the state from the half-clutch state according to the depression amount of the inching pedal 89 to the complete release of the clutches 20 and 26 is realized in the regions c to d in FIG.

The bypass valve 610 connecting the main line oil passage 606 and the bypass oil passage 621 applies the high line pressure from the main line oil passage 606 only at the beginning of a gear shift to the bypass oil passage 621, the oil passage 620 and the front and rear. Clutches 20 and 26 via the forward switching valve 619
One side of a spool (not shown), which is a type of two-position switching valve adapted to be supplied to the side, and is provided with a non-energized closing type bypass solenoid valve 609 in which the energized state is maintained for a certain period of time by the ECU 63 in accordance with the shift operation. The pilot pressure branched from the energized main line oil passage 606 decreases, and the main line oil passage 606 and the bypass oil passage 621 communicate with each other.

That is, the clutch 2
Supply hydraulic pressure to 0,26 is temporarily reduced, and brake 3
After performing the selective engagement operation and the release operation for 5, 38, 43, 48, 55, and 56, the hydraulic oil is again applied to the clutch 20,
When supplying to the 26 side and engaging it, the bypass solenoid valve 609 is energized for a certain period of time, and the high line pressure from the main line oil passage 606 is temporarily passed through the bypass oil passage 621 and the oil passage 620. It is supplied from the forward / reverse switching valve 619 to the clutches 20, 26 as it is. As a result, the time required for backlash before the engagement of the clutches 20 and 26 actually starts is reduced,
It is possible to shorten the time until the shift is completed.

Therefore, the energizing time for the bypass solenoid valve 609 is determined by the following procedure: when the hydraulic oil is temporarily drained from the clutches 20 and 26 with the start of the gear shift, and then the hydraulic oil is supplied again and engaged. What is necessary is just to set in accordance with the time required for the clearance before the engagement actually starts.

FIG. 7 and the sequence valve 602, the pressure control valve 608,
As shown in FIG. 13 showing an enlarged sectional structure of a portion of the pressure reducing valve 615, the sequence valve 602 includes an inlet port 650 connected to an oil passage 603, and a main outlet port 65 connected to a main line oil passage 606.
1 and a pilot outlet port 652 connected to the main pilot oil passage 607, and the oil sump 6
A valve body 653 having an oil discharge port EX _1, EX ₂ communicating with the 01, a spool 655 which forms an annular groove 654 in the central portion, slidably in one end of the spool 655 (left side in the figure) A compression coil spring interposed between the combined plug 656 and the spool 655 and the valve body 653 to bias the spool 655 toward the plug 656.
657. The oil chamber 658 and the annular groove 654 surrounded by the spool 655 and the plug 656 are in communication with each other through an oil hole 659.

Therefore, when high line pressure is not supplied from the oil passage 603 to the inlet port 650, the spool 655 is pressed against one end of the valve body 653 by the spring force of the compression coil spring 657 as shown in FIG. 651 is spool 655
It is in a state of being closed by. Here, when high line pressure is supplied from the oil passage 603 to the inlet port 650, high line pressure is supplied to the main pilot oil passage 607 from the pilot outlet port 652 which is in communication with the inlet port 650 via the annular groove 654. The pilot pressure from the main pilot oil passage 607 is changed to a high-speed / low-speed switching valve 614, a forward / reverse switching valve 619, a 1.5-speed-3.
It acts on the 7-speed switching valve 624 and the 2 / 6-speed-4 / 8-speed switching valve 628, respectively.

In this state, as high-pressure oil is further supplied to the sequence valve 602, high-line pressure is also supplied from the oil hole 659 into the oil chamber 658, and the spool 655 is compressed by the compression coil spring 657. It gradually moves to the other end side (the right side in the figure) of the valve body 653 against the spring force. As a result, the inlet port 650 communicates with the main outlet port 651 via the annular groove 654, while the pilot outlet port 652 is closed by the spool 655, and the high line pressure is controlled from the main line oil passage 606 by the pressure control. It is supplied to the valve 608 side.

When the pressure oil in the oil chamber 658 is discharged from _one oil discharge port EX1 through the gap between the spool 655 and the plug 656, the spool 655 is pushed back again by the spring force of the compression coil spring 657. As a result, the inlet port 650 and the pilot outlet port 652 communicate with each other.

The pressure control valve 608 is connected to the brakes 35, 38, 43, 48, 55, 56 and the clutch 2 during shifting.
This is for gradually increasing the supply oil pressure to the oil tanks 0, 26 from a low pressure to a high pressure, and communicates with an inlet port 660 connected to the main line oil passage 606, an outlet port 661 connected to the high line oil passage 611, and the oil sump 601. A valve body 662 having an oil discharge port EX, and an inlet port 660 and an outlet port 66
Spool with an annular groove 663 formed in the center that can communicate with 1
664 and a piston 665 with a larger outer diameter than this spool 664
And a compression coil spring 666 interposed between the piston 665 and the spool 664. The spool 664 has an oil chamber opening at one end of the spool 664.
The oil chamber 667 and the annular groove 663 are in communication with each other via an oil hole 668. A pressure regulating chamber 669 partitioned by the other end of the valve body 662 and the piston 665 is connected to a high-line oil passage via a pressure regulating oil passage 671 provided with an orifice 670 in the middle.
Connected to 611.

Here, the pressure oil in the pressure adjusting oil passage 671 is rapidly discharged at the time of the gear shifting operation, and the piston 665 is quickly returned to the state shown in FIG. In order to shift the oil pressure to the lowest state, the pilot pressure from the high line oil passage 611 and the pressure oil passage 671 acts on both sides of a spool (not shown) in the middle of the drain oil passage 672 branched from the pressure adjustment oil passage 671. The switched switching valve 673 is interposed. The pilot oil passage 674 for guiding the pilot pressure from the pressure adjusting oil passage 671
In the middle of the operation, a non-energizing closed solenoid valve that duty-controls the rise of the hydraulic pressure in the pressure regulating oil passage 671 during shifting
675 are provided.

Therefore, when the gear change operation is started in the state shown in FIG. 13, the brakes 35, 38, 43, 48, 5
Since the pressure oil is discharged from the engagement state of 5,56, the pilot pressure on the opposite side to the pilot oil passage 674 is temporarily reduced, and the position of the switching valve 673 is switched. The pressure oil in the pressure chamber 669 is discharged from the pressure adjusting oil passage 671 via the oil discharge passage 672. As a result, the piston 665 is quickly displaced to the other end side of the valve body 662, and the high line
Since the high line pressure hydraulic oil starts to be supplied from the main line oil passage 606 via 1, the pilot pressure on the opposite side to the pilot oil passage 674 increases again, and the position of the switching valve 673 is returned to the original state shown in FIG. Switch to. The pressure control oil passage 671 and the pressure control chamber 6
The hydraulic pressure at 69 increases, and the piston 665 is pressed against one end of the valve body 662 against the spring force of the compression coil spring 666, and the clutches 20, 26 and the brakes 35, 38, 43, 48, 55, 56
The supply oil pressure for the oil gradually rises.

At this time, the duty ratio of the energization state to the solenoid valve 675 is duty-controlled, so that the rate of increase of the supply oil pressure to the clutches 20, 26 and the brakes 35, 38, 43, 48, 55, 56 can be gently corrected. Becomes
A shift operation with almost no shock can be realized.

The pressure reducing valve 615 has a valve body 678 having a through port 676 bridging the high line oil passage 611, an outlet port 677 connected to the low line oil passage 616, and an oil discharge port EX communicating with the oil reservoir 601. And a spool 680 having an annular groove 679 formed on the outer peripheral surface that slides in the valve body 678 and faces the through port 676, and attaches the spool 680 to one end (left side in the figure) of the valve body 678. And a biasing compression coil spring 681. The control oil chamber 682 formed between one end of the valve body 678 and the spool 680 has a control oil passage 683 branched from a high line oil passage 611 between the pressure control valve 608 and the pressure reducing valve 615. Are in communication. Also, the other end of the valve body 678 and the spool
Oil hole formed on the other end of the spool 680
A pressure regulating chamber 685 which can communicate with the outlet port 677 via 684
Are formed.

Therefore, when a high line pressure is supplied from the high line oil passage 611 and the control oil passage 683 to the through port 676 and the control oil chamber 682 in the state shown in FIG. 13, the spool 680 receives the high line pressure. The compression coil spring 68
It moves to the other end side of the valve body 678 against the spring force of 1, and the through port 676 and the outlet port 677 communicate. As a result, the high line pressure from the high line oil passage 611 is supplied to the low line oil passage 616, and the high line pressure is also supplied from the oil hole 684 to the inside of the pressure regulation chamber 685.

At this time, the oil discharge port EX is closed by the spool 680, and the spool 680 is again moved to one end of the valve body 678 by the hydraulic pressure of the pressure regulating chamber 685 and the spring force of the compression coil spring 681. Is pushed back to. As a result, the pressure regulation chamber 685 communicates with the oil discharge port EX, and the oil pressure in the low line oil passage 616 decreases. In this way, the spool 680 reciprocates in the valve body 678, and the pressure oil supplied to the low line oil passage 616 is adjusted to the low line pressure.

When the shift lever 62 is selected to the P range, only the neutral solenoid valve 612 is energized, and the pressure oil is discharged from all the brakes 35, 38, 43, 48, 55, 56, and Only the clutch 26 can be engaged. However, in this case, the pressure oil in the control oil chamber 682 is drained through the oil passage 686 that connects the high-speed / low-speed switching valve 614 and the control oil passage 683. 7
And the state shown in FIG. Then, the pressure oil supplied to the forward clutch 26 is supplied to the oil passage 620, the inching valve 617,
Oil is discharged from the oil discharge port EX of the pressure reducing valve 615 via the low line oil passage 616, and as a result, the forward clutch 26 is also substantially released, and a driving force is transmitted from the transmission input shaft 14 to the drive gear 24 side. An untransmitted neutral state is achieved. On the other hand, in the P range, the mechanical hydraulic brake 88 is engaged by an actuator (not shown), and the rotation of the transmission output shaft 50 is mechanically restricted.

When the shift lever 62 is selected in the N range, the neutral solenoid valve 61 is operated in the same manner as in the P range.
Only 2 is energized and all brakes 35, 38, 4
The pressure oil is discharged from 3, 48, 55, and 56, and only the forward clutch 26 can be engaged.
6 is also substantially in the open state, and a neutral state in which the driving force is not transmitted from the transmission input shaft 14 to the drive gear 24 side is realized. In this case, as a matter of course, the mechanical hydraulic brake 88 is open.

When the shift lever 62 is selected to the D range, the ECU 63 determines a map as shown in FIG. 14 in a ROM stored in the ECU 63 in advance based on detection signals from the vehicle speed sensor 67 and the accelerator opening sensor 70. , An optimal gear position for the current operation state is read from the controller. If the gear position does not match the current gear position, the gear shift operation described below is automatically performed. In this case, the current gear stage is determined by the EC for each solenoid valve 612, 613, 618, 622, 623, 626, 627 for shifting.
It is calculated in the ECU 63 based on the output signal from U63.

That is, when a shift start signal is output, the corresponding shift electromagnetic valves 612, 613, 618, 622, 623, 62 correspond to the shift start signal.
The energization state for 6,627 is selectively switched. In this case, as described above, the switching valve 673 temporarily opens the oil discharge passage 672 to quickly move the piston 665 of the pressure control 608 to the right side in the drawing, so that the high line oil The high line pressure of the road 611 has dropped to the lowest state, and from this state the high line pressure gradually rises with the duty of the solenoid valve 675, and a smooth shift operation with almost no shift shock is performed.

At this time, the bypass valve 610 temporarily connects the main line oil passage 606 and the bypass oil passage 621 by the bypass solenoid valve 609 in parallel with the rise of the high line pressure.
As a result, the high line pressure is supplied from the oil passage 620 to the clutches 20 and 26 via the forward / reverse switching valve 619, and the backlash is quickly performed so that the engagement operation by the low line pressure is performed. Thus, the time until the shift is completed can be shortened.

The shift map shown in FIG. 14 is a power mode map that draws out the driving force of the engine 11 while maintaining the shift speed on the low speed side with respect to the amount of depression of the accelerator pedal 69, but in the present embodiment. In addition, accelerator pedal 6
There is also a not-shown economy mode shift map that makes it easy to shift to the higher gear stage for the depression amount of 9 and saves fuel. For this reason, a fuel consumption mode changeover switch 91 is provided in the cabin (not shown) for selecting the switching between the power mode and the economy mode, and a detection signal from the fuel consumption mode changeover switch 91 is output to the ECU 63. ing.

The information on the shift mode selected by the fuel efficiency mode changeover switch 91 is displayed on an operating state display device 92 provided on a steering console (not shown) in the cabin. The information on the gear position and the position of the shift lever 62 are also displayed at the same time.

As is clear from the shift map shown in FIG. 14, in this embodiment, when the automatic shift is performed in the D range, the fifth range, and the third range, the speed ratio is very close to the second speed and the fourth speed. The shift operation to the third gear is not performed, and a so-called jump shift is automatically performed between the second gear and the fourth gear.

When the shift mode changeover switch 71 is operated once from the state of the automatic shift mode in which the shift lever 62 is set to the D range, the driver enters the manual shift mode desired by the driver and the current shift mode is set. The gear position is maintained as it is. When the shift lever 62 is operated once, for example, to the UP position, the output signal from the reference position sensor 81 is turned off and the output signal from the upshift switch 82 is turned on. The shift operation of the upshift that is advanced by one is performed, and the shift operation itself is performed in the same manner as the shift operation in the D range described above.

When shifting from a high gear to a low gear, for example, if the gearshift lever 62 is operated five times successively from the eighth gear to the DW position to desire a sudden downshift to the third gear, If there is a possibility that the engine speed may exceed the critical speed if the speed change is performed in this state, the shift is not started until the engine speed decreases to a safe speed. Similarly, in the case of operating the forward / reverse switching lever 61 to switch the traveling direction of the vehicle, the shift operation is not performed until the vehicle completely stops based on the detection signal from the vehicle speed sensor 67. This is the same even in the case of the automatic transmission in which the D range, 5 range or 3 range is selected.

When the shift lever 62 is selected in five ranges, a shift operation is automatically performed according to the shift map in the economy mode (not shown) in FIG. 14 based on the detection signals from the vehicle speed sensor 67 and the accelerator opening sensor 70. However, in these five ranges, all the high gears above the sixth gear are clipped to the sixth gear, and the gears are not shifted to the seventh gear or more. Also in this case, the third gear is not selected as in the case of the D range, and the jump gear is automatically performed between the second gear and the fourth gear.

Similarly, when the shift lever 62 is selected to be in three ranges, it is not shown in FIG. 14 or not shown based on the detection signals from the vehicle speed sensor 67 and the accelerator opening sensor 70 just like the case of the five ranges described above. The shift operation is automatically performed according to the shift map in economy mode.
In the three ranges, all the higher gears than the fourth gear are clipped to the fourth gear, and the gear is not shifted to the higher gear than the fifth gear. Also in this case, similarly to the D range and the fifth range, the third speed is not selected, and the jump speed is automatically performed between the second speed and the fourth speed.

As shown in FIG. 15 showing the flow of such a shift operation process, when the ignition key switch (not shown) is turned on, the engine 1 is first turned on in step S1.
In step S2, various initial values for the control of the driving state and the shift control are set, and the vehicle speed is calculated based on the detection signal from the vehicle speed sensor 67 in step S2. The accelerator opening is calculated based on the accelerator opening.

Next, in step S3, the selected positions of the forward / reverse switch 61, the shift position sensor 68, and the fuel efficiency mode switch 91 are detected, and the high / low speed switch valve 614 and the forward / reverse switch valves 619, 1.5 are detected. The current gear position is calculated in step S4 based on the output signals to the speed-3 / 7 speed switching valve 624 and the 2.6-6 speed-8 / 8 speed switching valve 628.

Then, in step S5, these information are output to the operation state display device 92. In step S6, calculation errors and abnormalities in the ECU 63 are detected. Is output to the operation state display device 92.

Thereafter, the vehicle speed information and the accelerator opening information and the fuel efficiency mode changeover switch 91 shown in FIG.
4 or a shift map in the economy mode (not shown) in step S7.
The ideal shift timing for the position of the shift lever 62 at 8 is calculated. Then, this is output to the hydraulic control device 60 in step S8, and a predetermined shift operation is performed.

The above steps S1 to S8 are repeated every control cycle (for example, every 15 milliseconds) until the ignition key switch (not shown) is turned off.

In this embodiment, an emergency electronic control unit 93 is provided for enabling manual shift operation when the ECU 63 fails. The emergency electronic control unit 93 includes the ECU 63 and the emergency electronic control unit 93. Power switch 94 for operating one of the electronic control units 93
And F2 (second forward speed), N (neutral), and R2 (second forward speed) for emergency escape, which can realize the second forward speed, the neutral speed, and the second reverse speed without operating the forward / reverse selector switch and the shift lever 62. And a position change-over switch 95 for selecting a position (reverse second speed).

Therefore, when the operation of the ECU 63 is selected by operating the power switch 94, the power supply 96 and the EC
While U63 is electrically connected, the power supply to the emergency electronic control unit 93 is cut off, and the above-described normal gear shifting operation becomes possible.

If the ECU 63 does not operate normally for some reason, the fact that an abnormality has occurred in the ECU 63 is displayed on the driving information display device 92. The driver operates the power switch 94 based on this information. . As a result, the operation of the emergency electronic control unit 93 is selected, and the power supply 96 and the emergency electronic control unit 93 are electrically connected, while the power supply to the ECU 63 is cut off, and the position corresponding to the position of the position switch 95 is switched. The gear to be shifted is the hydraulic control device 6
Achieved via 0.

The bypass valve 610 described above
When the main line oil passage 606 and the bypass oil passage 621 communicate with each other at the time of gear shifting, high line pressure can be supplied from the pressure reducing valve 615 to the low line oil passage 616 as well. As shown in FIGS. 16 and 17 showing enlarged sectional structures of the bypass valve 610 and the pressure reducing valve 615 in such another embodiment of the present invention, the spool 680 and the valve body 678 of the pressure reducing valve 615 are combined. Bypass spool 687 fitted slidably,
The valve body of the pressure reducing valve 615 is coaxial with the spool 680 of the pressure reducing valve 615 and has one end facing the control oil chamber 682.
678 also serves as a valve body of the bypass valve 610.

At the center of the bypass spool 687, a main line oil passage 606 communicating with the inlet port 688 and an outlet port 68
Annular groove 690 that can connect to bypass oil passage 621 communicating with 9
Is formed at the other end of the bypass spool 687.
A spring receiving portion 691 is formed. A compression coil spring 692 is interposed between the spring receiving portion 691 and the valve body 678 to urge the bypass spool 687 rightward in the drawing to shut off the inlet port 688 and the outlet port 689. ing.
Also, the pilot port 693 facing the other end of the spring receiving portion 691
A pilot oil passage 695 provided with an orifice 694 on the way is formed between the
In the middle of the pilot oil passage 695 between the pilot port 943 and the pilot port 693, a bypass solenoid valve 696 that is open when not energized is interposed.

Therefore, when the gearshift operation is not performed, the pressure oil of the pilot port 693 is drained from the pilot oil passage 695 via the bypass solenoid valve 696, and the bypass spool 687 is displaced by the spring force of the compression coil spring 692. Valve 67
8 is urged to the other end (right side in the figure), and the inlet port 688 and the outlet port 689 are shut off as shown in FIG.

Here, the clutches 20 and 26 in the engaged state are temporarily released by the shift start signal, and the brake 3
After performing the engagement operation and the release operation with respect to 5, 38, 43, 48, 55, 56, the clutch 20,
When the valve 26 is re-engaged, the bypass solenoid valve 696 is energized for a certain period of time, and the high line pressure from the main line oil passage 606 is applied to the pilot port 693 via the pilot oil passage 695.
Supplied to As a result, as shown in FIG. 17, the bypass spool 687 moves to the left in the drawing against the spring force of the compression coil spring 692, and the inlet port 688 and the outlet port 689 communicate with each other via the annular groove 690. Therefore, the high line pressure is temporarily supplied from the main line oil passage 606 directly to the clutches 20 and 26 via the bypass oil passage 689 and the forward / reverse switching valve 619. At the same time, the spool 680 of the pressure reducing valve 615 is also pushed back to the left in the drawing, and the high line oil passage 611 and the low line oil passage 616 are in communication with each other, so that the high line pressure from the high line oil passage 611 is also low. The oil is supplied from the line oil passage 616 to the oil passage 620 via the inching valve 617. As a result, the time required for loosening until the engagement of the clutches 20 and 26 actually starts is reduced, and the time until the shift is completed can be shortened.

In FIGS. 16 and 17, members having the same functions as those shown in FIGS. 7, 8 and 13 described in the previous embodiment are denoted by the same reference numerals. In the embodiment, the spool 680 of the pressure reducing valve 615 is provided with the orifice 697 through which the annular grooves 679 and 682 can be communicated, but is not necessarily provided.

[0079]

According to the hydraulic control apparatus for a transmission of the present invention, the pressure reducing valve is temporarily bypassed during gear shifting to prevent non-pressure reduction.
State pressure oil is directly applied to the forward and reverse friction engagement elements.
And a bypass valve for supplying to the bypass valve.
When the valve is opened, the pressure regulating operation of the pressure reducing valve is forcibly stopped.
As a result, the time required to reduce the gap before the engagement of the forward and reverse frictional engagement elements actually starts is reduced, and the time required to complete the shift is shortened to improve the shift feeling. It became possible to do.

[Brief description of the drawings]

FIG. 1 is a control block diagram of an embodiment in which a DPS hydraulic control device according to the present invention is mounted on a motor grader with eight stages in both forward and backward directions.

FIG. 2 is a conceptual diagram of a drive system in the present embodiment.

FIG. 3 is a schematic diagram illustrating a select pattern of a shift lever according to the present embodiment.

FIG. 4 is a cross-sectional view illustrating a schematic structure of a portion of a shift lever according to the present embodiment.

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

FIG. 6 is an operation element diagram showing a relationship between an engagement state of a friction engagement element and each shift speed in the embodiment.

FIG. 7 is a hydraulic circuit diagram illustrating an example of a hydraulic control device in the present embodiment together with FIG.

FIG. 8 is a hydraulic circuit diagram illustrating an example of a hydraulic control device according to the present embodiment together with FIG.

FIG. 9 is an operation element diagram showing a relationship between an engagement state of a shift electromagnetic valve and each shift speed in the embodiment.

FIG. 10 is an operation principle diagram showing an enlarged cross section of a portion of an inching valve in the present embodiment together with FIG. 11;

11 is an operation principle diagram showing an enlarged cross section of a portion of an inching valve in the present embodiment together with FIG.

FIG. 12 is a graph showing a relationship between a duty ratio of an electromagnetic valve attached to an inching valve and an engagement hydraulic pressure of a clutch in the embodiment.

FIG. 13 is an enlarged cross-sectional view of a sequence valve, a pressure control valve, and a pressure reducing valve in this embodiment.

FIG. 14 is a shift map showing a relationship among a vehicle speed, an accelerator opening, and a shift speed in a power mode in the embodiment.

FIG. 15 is a flowchart illustrating a flow of processing of a main part in the present embodiment.

16 is an operation principle diagram showing an enlarged cross section of a part of a pressure reducing valve and a bypass valve in another embodiment of the DPS hydraulic pressure control apparatus according to the present invention, together with FIG. 17;

FIG. 17 is an operation principle diagram showing an enlarged cross section of a part of a pressure reducing valve and a bypass valve in another embodiment of the DPS hydraulic pressure control apparatus according to the present invention together with FIG. 16;

FIG. 18 is a hydraulic circuit diagram illustrating a concept of a conventional hydraulic control device for a DPS.

[Explanation of symbols]

11 is an engine, 12 is a crankshaft, 13 is a damper, 14 is a transmission input shaft, 15 is a reverse sun gear, 16 is a forward sun gear, 17 is a reverse planetary gear, 18 is a reverse planetary carrier, and 19 is a reverse planetary gear. Transmission case, 20 is a reverse clutch, 2
1 is a forward planetary gear, 22 is a forward planetary carrier, 23
Is a reverse internal gear, 24 is a drive gear, 25 is a forward internal gear, 26 is a forward clutch, 27 is a transmission gear group, 28
Is an input gear, 29 is a fourth planet carrier, 30 is an intermediate shaft,
31 is a fourth sun gear, 32 is a fourth planetary gear, 33 is a third planetary gear, 34 is a fourth internal gear, 35 is a 4.8 speed brake, 36 is a third sun gear, and 37 is a third internal gear. , 38 is a 3.7 speed brake, 39 is a second planetary carrier, 40 is a second sun gear, 41 is a second planetary gear, 42 is a second internal gear, 43 is a 2.6 speed brake, and 44 is a first gear. Planet carrier, 45 is a first sun gear, 46 is a first planetary gear, 47 is a first internal gear, 48 is a 1.5 speed brake, 49 is an output bevel gear, 50 is a transmission output shaft, and 51 is a high / low switch. Planet carrier for high / low switching, 53 for planet gear for high / low switching, 54 for internal gear for high / low switching, 55 for low speed brake, 56 for high speed brake, 57 for pump driving gear, 58 for pump driving gear A transmission gear, 59 is an oil pump, 60 is a hydraulic control device, 61 is a forward / reverse switching level. Over, 62 the shift lever, 6
3 is an ECU (electronic control unit), 64 is a forward / reverse changeover switch, 65 is an engine speed sensor, 66 is a transfer speed sensor, 67 is a vehicle speed sensor, 68 is a shift position sensor, 69 is an accelerator pedal, and 70 is an accelerator opening. Degree sensor, 71 is a shift mode changeover switch, 72 is a sensor bracket, 73 is a pivot for manual shift, 74, 75
Is a pivot support bracket, 76 is a rotary shaft, 77 is a transmission lever case, 78 is an upper plate, 79 and 80 are openings, 8
1 is a reference position sensor, 82 is an upshift switch, 8
3 is a downshift switch, 84 is a spring support arm, 8
5 is a tension coil spring, 86 is a base plate, 87 is an opening, 88 is a mechanical hydraulic brake, 89 is an inching pedal, 90 is an inching opening sensor, 91 is a fuel consumption mode changeover switch, 92 is an operation state display device, 93 Is an emergency electronic control unit, 94 is a power switch, 95 is a position switch, and 96 is a power supply. 601 is an oil reservoir, 602 is a sequence valve, 603 is an oil passage, 604 is a relief valve, 605 is a pressure adjustment oil passage, 606 is a main line oil passage, 607 is a main pilot oil passage, 608 is a pressure control valve, and 609. Is a bypass solenoid valve, 610 is a bypass valve, 611 is a high line oil passage, 612 is a neutral solenoid valve, 613 is a low speed solenoid valve, 614 is a high speed / low speed switching valve, 615 is a pressure reducing valve, 616 is a low line oil 617 is an inching valve, 618 is a reverse solenoid valve, 619 is a forward / reverse switching valve, 620 is an oil passage, 621 is a bypass oil passage, 622 is a 3/7 speed solenoid valve, 62
3 is a 1.5-speed solenoid valve, 624 is a 1.5-speed to 3-7-speed switching valve, 625 is a branch high-line oil passage, 626 is a 4 / 8-speed solenoid valve,
627 is a 2.6-speed solenoid valve, 628 is a 2.6-speed / 4- to 8-speed switching valve, 629 is an inlet port, 630 is an outlet port, 631 is a valve body, 6
32 is a control spool, 633 is an inching spool, 634 is an annular groove, 635 is an inner spool, 636 is a control oil chamber, 637 is a control oil passage, 638 is an orifice, 639 is a solenoid valve for inching,
640 is a compression coil spring, 641 is a compression coil spring, 642 is a pressure regulation oil chamber, 643 is an oil hole, 644 is an oil hole, 645 is an oil drain oil hole, 646
Is an oil hole, 647 is an adjusting oil hole, 648 is a spring receiving portion, 649 is a stepped portion, 650 is an inlet port, 651 is a main outlet port, 652 is a pilot outlet port, 653 is a valve body, 654 is an annular groove, 655. Is a spool, 656 is a plug, 657 is a compression coil spring, 658 is an oil chamber, 659 is an oil hole, 660 is an inlet port, 661 is a high line oil passage, 662 is a valve element, 663 is an annular groove, 664 is a spool, 665 Is a piston, 666 is a compression coil spring, 667 is an oil chamber, 668 is an oil hole, 669 is a pressure regulating chamber, 670 is an orifice, 671 is a pressure regulating oil passage, 6
72 is an oil drain, 673 is a switching valve, 674 is a pilot oil, 675
Is a solenoid valve, 676 is a through port, 677 is an outlet port, 678 is a valve body, 679 is an annular groove, 680 and a spool, 681 is a compression coil spring, 682 is a control oil chamber, 683 is a control oil passage, and 684 is an oil hole. , 685
Is a pressure regulating chamber, 686 is an oil passage, 687 is a bypass spool, 688 is an inlet port, 689 is an outlet port, 690 is an annular groove, 691 is a spring receiving portion, 692 is a compression coil spring, 693 is a pilot port, and 694 is an orifice , 695 is a pilot oil passage, 696 is a solenoid valve for bypass, 697 is an orifice, EX ₁ and EX ₂ are oil drain ports, and EX is an oil drain port.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukihiro Masuko 3000 Tana, Sagamihara-shi, Kanagawa, Japan M-H.I-Sagami High-Tech Co., Ltd.・ Isagami High-Tech Co., Ltd. (56) References JP-A-61-45156 (JP, A) JP-A-2-118262 (JP, A) JP-A-49-6621 (JP, A) JP-A Sho 52- 156272 (JP, A) JP-A-61-24860 (JP, A) JP-B-46-33049 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-61 / 12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] A planetary gear mechanism for forward / reverse travel in which an input shaft end is directly connected to an output shaft of an engine, and a forward / backward travel mounted on a rotating element constituting the planetary gear mechanism for forward / backward travel. Two friction engagement elements, a plurality of sets of planetary gear mechanisms for shifting connected to the planetary gear mechanism for forward and backward movement, and a plurality of shifts assembled to the rotating elements constituting the planetary gear mechanisms for shifting. A friction engagement element, a pressure reducing valve for lowering a supply oil pressure to the forward and reverse friction engagement elements than a supply oil pressure to the speed change friction engagement element, and a selective valve for these friction engagement elements. In a direct power shift transmission including an electronic control unit capable of controlling the supply and discharge of the pressure oil to achieve a predetermined gear position, the pressure reducing valve is temporarily bypassed during shifting.
Non-depressurized pressure oil is directly applied to the forward and backward friction
A bypass valve for supplying the
When the valve is opened, the pressure regulating function of the pressure reducing valve is forcibly stopped.
Hydraulic control system is characterized in that so as to locked.