JPS6261841A - High speed backward propulsion braking device for vehicle - Google Patents

Abstract

PURPOSE:To disable backward movement of a vehicle when a speed changed gear operates at a high speed, by disposing an unloader valve which actuates in association with a high speed detecting means in the speed change gear, in a backward moving side hydraulic oil supply passage for a forward and backward changeover device. CONSTITUTION:In a travel transmission system 9 for transmitting power from an engine 2 to rear wheels, there are provided a clutch 10, a forward and backward change-over device 11, a speed change gear 12 and a means for detecting high speed operation of the speed change gear 12. Further, an unloader valve which actuates in association with the detecting operation of the high speed operation detecting means is disposed in a backward moving side hydraulic passage for supplying hydraulic oil into the forward and backward change-over device 11. Further, a forward and backward lever 18 is turned into a forward position F or a rearward position R to energize a control valve 16 so that a forward and backward change-over device 11 is changed into a forward or backward movement condition. Accordingly, during backward movement, the high speed detecting means detects such a condition that the speed change gear 12 is manipulated to a highest speed position, and therefore, an unload valve is pressed by means of an actuating means to be opened, and therefore, the forward and backward change-over device 11 is returned to a neutral position to disable backward movement.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a high-speed reversing restraining device for a vehicle such as a tractor, and the present invention relates to a high-speed reversing restraining device for a vehicle such as a tractor, which unloads the reversing side hydraulic circuit when the transmission is at high speed and the forward/reverse switching device is in reverse. The valve is activated to make it impossible to go backwards.

<Prior art and its problems> The traveling transmission system of a tractor incorporates a transmission device consisting of a main transmission section, an auxiliary transmission section, a creep transmission section, etc., and a combination of these transmission sections enables multi-speed shifting. It has become.

Conventionally, in this type of transmission system, the reverse gear has a larger reduction ratio than the forward gear and is usually incorporated into the main transmission section, so the maximum speed when traveling backward is lower than that when traveling forward. is common.

However, with the advent of vehicles that are equipped with a forward/reverse switching device in the travel transmission system and can easily switch between forward and reverse with a single forward/reverse switching lever, the transmission has been set to the highest forward speed. If the forward/reverse switching device was set to reverse in this state, the vehicle would reverse at a very high speed, causing the problem that the maximum speed during reverse would be too high.

The present invention was provided for the purpose of solving such conventional problems.

Means for Solving the Problems> The present invention disables backward movement when the transmission is at high speed, and as a specific means for that purpose, the traveling transmission system 9
In a vehicle equipped with a multi-stage transmission 12 and a hydraulic forward/reverse switching device 11, a high speed detection means 39 for detecting the high speed of the transmission 12 is provided, and the detection operation of the high speed detection means 39 is Unload valve 23 that operates in conjunction with
, the reverse side oil passage 2 that supplies pressure oil to the forward/reverse switching device 11
1.

Function> When the forward/reverse switching lever 1 is operated to the forward position F or the reverse position R, the control valve 16 is activated and the forward/reverse switching device 11 is switched to forward or reverse.

Therefore, when an attempt is made to operate the transmission 12 to the highest speed next time, the high speed detection means 39 detects this and presses the pressing rod 24 of the unload valve 23 via the actuation means 61, so that the unload valve 23 is activated. Open. Therefore, the forward/reverse switching device 11 returns to neutral, making it impossible to move backward.

<Example> Hereinafter, the present invention will be described in detail with reference to the illustrated example.
In the figure, l is a tractor body, which consists of an engine 2, a transmission case 3, and the like. 5 is a hydraulic system, 6 is a rear wheel fender, and 17 is a driver's seat, with left and right rear wheel fenders.
It is provided on a floor cover 8 installed between the two.

, a traveling transmission system 9 that transmits power from the engine 2 to the rear wheels.
As shown in FIG. 2, a clutch 1o, a forward/reverse switching device 11, a transmission 12, etc. are provided, and the transmission 12 includes a main transmission part 13, a sub-transmission part 14, a creep transmission part 1
It consists of 5 gears and can be shifted in multiple stages.

The forward/reverse switching device 11 is a hydraulic type, and the tractor body 1
It can be controlled by a control valve 16 provided at an appropriate location.

As shown in FIGS. 3 to 5, the control valve 16 is a rotary type having a built-in valve body 17 in its main body 17 that is linked to a forward/reverse switching lever 18, and is capable of moving the switching lever 18 from a neutral position N to a forward position. When operated in F position, pressure oil from the hydraulic pump 19 flows through the oil passage 20 to the forward side of the forward/reverse switching device 11, and conversely, when operated to the reverse position R, pressure oil from the hydraulic pump 19 flows through the oil passage 21. They are respectively supplied to the reverse side of the forward/reverse switching device 11 via the forward/reverse switching device 11. Furthermore, an unload valve 23 is built into the main body 17 to open and close between the reverse side oil passage 21 and the drain hole 22, and its press rod 24
is protruded from the lower side of the main body 17, and is biased by a coil spring 25 fitted around the press rod 24 so that the unload valve 23 is closed.

The main transmission section 13, the auxiliary transmission section 14, and the creep transmission section 15 of the transmission 12 are built into the transmission case 3.
It can be operated by a main shift lever 26, a sub shift lever 27, and a creep shift lever 28, respectively. That is, as shown in FIG. 6, the main speed change lever 26 is attached to an operating shaft 30 inserted into and supported by a speed change stand 29, so that the main speed change section 13 can be operated by front and rear and left and right operations. The sub-shift lever 27 is attached to the support plate 3 fixed to the support member 31 of the floor cover 8.
2 via a support shaft 33, and is interlocked with an operating shaft 37 via a link 34, a rod 35, and a link 36. The creep shift lever 28 is pivotally supported by an operating shaft 38.

39 is a high speed detection means for detecting that each transmission section 13, 14, 15 is in the highest speed state, and is constructed as shown in FIGS. 6 to 8. That is, on the support shaft 40 fixed to the support plate 32, there is a boss portion 43 having engagement links 41 and 42.
．． 44 is fitted on the sleeve, and each boss 43 and 44 is provided with a projection 45,46. An engagement lever 47 at the outer end of the operating shaft 30 for main transmission is engageable with the protrusion 45 , and an engagement lever 48 on the side of the sub-transmission lever 27 is engageable with the protrusion 46 . When the high speed levers 27 and 28 are operated to put the .14 into the high speed state, the engagement link 41
．． 42 is configured to rotate upward around the support shaft 40. A first operating link 49 is movably provided between the distal ends of the engagement links 41 and 42, and a connecting member 50 at the intermediate point thereof.
An inner 52 of the Bowden wire 51 is connected to the inner part 52 of the Bowden wire 51. The outer 53 of the Bowden wire 51 is attached to an outer fixture 56 that is connected to the second operating link 54 by a pin 55. The second operating link 54 is located below the first operating link 49, one end of which is pivotally supported by a pin 58 to a bracket 57 projecting downward from the support plate 32, and the other end connected to the creep shift lever 28 with a pin 59. has been
When the creep speed change lever 28 is operated to the high speed position indicated by the solid line, it is lowered around the pin 58. Therefore, this high-speed detection means 39 is configured such that when the high-speed lever 26, 27 is operated to the high-speed position, the first operating link 49 is raised, and when the creep shift lever 28 is operated to the high-speed position, the second operating link 54 is lowered. bowden wire 51
The inner 52 of the transmission device 12 is pulled up relatively.
The maximum speed is detected.

Note that 60 is a PTO gear shift lever.

Bowden wire 51 is connected to operating means 61 so as to operate unload valve 23 incorporated in control valve 16 of forward/reverse switching device 11 . As shown in FIGS. 3, 4, and 9, the actuating means 61 includes a swing arm 62, a holding plate 63, an actuating arm 64, and the like.

The swing arm 62 is pivotally supported by a pin 66 on a bracket 65 fixed on the main body 17 side of the control valve 16, and is operatively connected to the forward/reverse switching lever 18 via a pin 67, and has a protrusion 68. . The retaining plate 63 is a fixed bracket 69
It is pivotally attached to the body by a pin 70 so as to be freely swingable, and the outer 53 of the Bowden wire 51 is attached to a fixing portion 71 provided thereon. The operating arm 64 is slidably inserted into the holding plate 63 in the longitudinal direction.
The inner 52 of the Bowden wire 51 is attached to one end with a connector 72, and a cam portion 73 is formed at the other end to be rotated around a pin 70 by a protrusion 68 of a swing arm 64.

The actuating arm 64 is provided with a pressing part 74 corresponding to the pressing rod 24, and when the actuating arm 64 rotates around the pin 70, the pressing part 74 presses the pressing rod 24 to open the unload valve 23. It is set to be open.

In the above configuration, the forward/reverse switching lever 18 is moved to the forward position F.
Alternatively, if the vehicle is operated to the reverse position R, the valve body 17 of the control valve 16 rotates, and the forward/reverse switching device 11 is switched to forward or reverse. If the forward/backward cutting lever 18 is set to the reverse position R, the swing arm 62 interlocked therewith is in the state shown in FIG. 4, and the protrusion 68 is in the downwardly protruding state.

Therefore, when an attempt is made to operate the transmission 12 to the highest speed next time, the high speed detection means 39 detects this and presses the pressing rod 24 of the unload valve 23 via the actuation means 61, so that the unload valve 23 is activated. Open. Therefore, the forward/reverse switching device 11 returns to neutral, making it impossible to move backward.

That is, when one or both of the main shift lever 26 and the auxiliary shift lever 27 are in a position other than the high speed position, the engagement link 4
Although the first operating link 49 supported by 1.42 is tilted or at a lower position, if both shift levers 26 and 27 are set to the high speed position, the first operating link 49 will rise as shown by the solid line in FIG. . On the other hand, if the creep shift lever 28 is set to the high speed side as shown by the solid line in the figure, the second operating link 54 will be lowered from the imaginary line to the solid line position. As a result, the inner 52 of the Bowden wire 51 is connected to the outer 53.
The transmission device 12, which combines the transmission parts 13, 14, and 15,
is at maximum speed.

When the inner S2 of the Bowden wire 51 is pulled, the actuating arm 64 of the actuating means 61 is pulled in the direction of the arrow shown in FIG. 3 and slides along the holding plate 63. At this time, if the switching lever 18 of the control valve 16 is set to the reverse position R and the forward/reverse switching device 11 is set to reverse, the protrusion 6 of the swing arm 62
8 protrudes downward as shown in FIG. 4, when the actuating arm 64 slides in the direction of the arrow shown in FIG. 70 tons of bottles! It then rotates in the direction of arrow C in Figure 3. Then, the pressing part 74 of the actuating arm 64 pushes the pressing rod 24 of the unload valve 23 against the spring 25, and the unload valve 23
is opened as shown in FIG. 5 and pressure oil flows into the drain hole 22, so the forward/reverse switching device 11 is turned off and becomes neutral, making it impossible to move backward.

When any one of the shift levers 26, 27, and 28 is operated to the low speed side, the high speed detection means 39 does not operate, the operating means 61 does not operate, the unload valve 23 closes, and the forward/reverse switching device 11 switches to reverse. Once the condition is restored, it is possible to drive backwards.

Figures 10-13 show another embodiment of the invention, which uses electrical means.

In FIG. 10, 76 is a battery, 77 is a main key switch, and 78 is a fuse box. Reference numeral 79 indicates a back lamp indicating that the vehicle is moving backward, and reference numeral 80 indicates a bank lamp inch, which is turned on when the forward/reverse switching device 11 is moving backward. The high speed detection means 39 includes a main speed change switch 81,
It consists of an auxiliary speed change switch 82, a creep speed change switch 83, etc., and these switches 81, 82, 83 are connected in series to a back lamp switch 80 and an output relay 84. An output contact of the output relay 84 is connected to a solenoid 85 of the actuation means 61.

As shown in FIG. 11, the solenoid 85 is connected to an actuating arm 64 which is pivoted by a pin 86, and the actuating arm 82 is adapted to push the pressing rod 24 of the unload valve 23.

The main shift switch 81 is connected to the gearbox 2 as shown in FIG.
9 in correspondence with the high-speed shift rod 87, and the main shift switch 81 is turned on when the shift rod 87 is slid to the high-speed side. Note that 88 is a shift fork, and 89 is a transmission cover.

As shown in FIG. 13, the creep speed change switch 83 has a bracket 91 integrally formed with a retaining plate 90 of the operating shaft 38.
The actuating plate 93 provided on the boss portion 92 of the operating shaft 38 is turned on during high-speed operation. Note that the sub-shift switch 82 is also attached with substantially the same structure.

In this case, when each speed change switch 81, 82, 83 is turned on and the back lamp switch 80 is turned on, the output relay 84 is activated, the solenoid 85 is energized and activated, and the arm 64 pushes the unload valve 23. Then, as in the case described above, it becomes impossible to go backwards.

<Effects of the Invention> According to the present invention, the high speed detection means 39 for detecting the high speed of the transmission 12 is provided, and the unload valve 23, which operates in conjunction with the detection operation of the high speed detection means 39, is connected to the forward/reverse switching device. Since it is provided in the reverse oil passage 21 that supplies pressure oil to the vehicle 11, it becomes impossible to reverse at high speeds, and safety is significantly improved.

In addition, since the unload valve 23 disables the forward/reverse switching device 11 from going backwards, if the gear lever is not operated at high speed, the gear lever may be bent or rattled due to forced operation. There is no fear that it will invite

[Brief explanation of drawings]

1 to 9 show a first embodiment of the present invention, in which FIG. 1 is a sectional side view of the rear part of the tractor, FIG. 2 is a block diagram of the traveling transmission system, and FIG. 3 is an unloading system. 4 is a front view of the valve actuating section, FIG. 5 is a cross-sectional view of the unloading valve, FIG. 6 is a side view of the high-speed detection section, FIG. 7 is a rear view of the same, and FIG. 8 is a side view of the same. FIG. 9 is a partially enlarged plan view, and FIG. 9 is a bottom view of the actuating means. FIGS. 10 to 13 show a second embodiment of the present invention. FIG. 10 is an electric circuit diagram, and FIG. 12 is a sectional view of the main shift switch mounting portion, and FIG. 13 is a side view of the creep shift switch mounting portion. DESCRIPTION OF SYMBOLS 1... Tractor body, 2... Engine, 9... Travel transmission system, 11... Forward/forward switching device, 12... Transmission device, 16... Control valve, 23... Unloading valve, 3
9... High speed detection means, 61... Actuation means.

Claims (1)

[Claims] 1. The traveling transmission system 9 includes a transmission 12 capable of multi-speed shifting;
In a vehicle equipped with a hydraulic forward/reverse switching device 11,
A high-speed detection means 39 for detecting the high speed of the transmission 12 is provided, and the unload valve 23, which operates in conjunction with the detection operation of the high-speed detection means 39, is connected to the reverse side oil path for supplying pressure oil to the forward/reverse switching device 11. 21. A high-speed reversing restraint device for a vehicle characterized by being provided in the vehicle.