JPS6239329A - Return-to-neutral mechanism of operating pedal for tractor equipped with hydraulic transmission - Google Patents

Abstract

PURPOSE:To allow a pedal to return stably to a neutral position by configurating a device in such a way that an operating arm is installed on a transmission as referred to the titled, the arm is interconnected with the pedal by way of a rod, and an adjusting arm is linked with the operating arm as specified while the adjusting arm is energized by a spring. CONSTITUTION:An operating arm is secured on an actuating axis 11 of a hydraulic transmission installed on a body 10 of a tractor. And a pedal 13 is rotatably pivoted around a pedal pivot 14 which is in parallel with the actuating axis 11, and the pedal 13 is pivotally interconnected with the operating arm 12 by way of a rod 15. And an adjusting arm 18 in a L like form is provided on the body 10 so as to be rotatable around an arm pivot 21 which is in parallel with the actuating axis 11, and is energized by a spring 22 so that the pedal 13 will always return to a neutral position. In addition, a floating roller 16 which comes in contact with the adjusting arm 18 when an ahead operation is effected by pressing the pedal 13, is rotatably pivoted on the operating arm 12, and an astern control floating roller 17 which comes in contact with the adjusting arm 18 when an astern operation is effected, is also rotatably pivoted on the adjusting arm.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a neutral return mechanism for an operating pedal in a tractor equipped with a hydraulic continuously variable transmission.

<Conventional Technology> Generally, in tractors equipped with a hydraulic continuously variable transmission (hereinafter referred to as HST) that can switch between forward and reverse, switching and shifting are performed by depressing a pedal. A spring is usually used to return this to the neutral position.

<Problem to be solved by the invention> However, as shown in Fig. 7, the return torque generated from the HST to the neutral position is due to the load acting on the HST (H5T
Depending on the input speed (oil pressure) and input rotation speed, the pedal pressure changes from positive (moment trying to return to the neutral direction toward the decelerating side) to negative (moment acting toward the accelerating side), and as a result, the pedal pressure increases. This will also cause changes in the pedal pressure and the feel of the neutral brake.

In this regard, in particular, since the neutral range of HST is quite narrow, stably and firmly returning the pedal to the neutral position is difficult due to the processing technology and assembly accuracy of the various components including the above-mentioned return spring, and it is costly. It also gets high.

What's more, in the case of a tractor, it is normal to carry out load-bearing work in the forward motion, and load-bearing work in the reverse motion is extremely rare. Where a large moment is applied to return the pedal to its original position, conventional mechanisms of this type apply constant pressure from the return spring to the pedal, without taking into account the frequency of use of the above-mentioned load work or changes in the moment. It is only given to .

Therefore, when going backwards during normal driving without a load, there is a risk that the aircraft will suddenly start, while when moving forward with a load, the pedals must be consciously depressed deeply, which makes it difficult to use them. There are problems that can easily lead to fatigue and incorrect operation.

<Means for Solving the Problems> The present invention is intended to solve these problems, and as a technical configuration for that purpose, it is possible to connect this to the operating shaft of the H5T mounted on the tractor body as a swinging fulcrum. an actuation arm mounted so as to be able to rotate together; and a pedal pivotally connected to the aircraft body so as to be able to swing around a pedal support shaft parallel to the actuation axis, and pivotally connected to the actuation arm by a rod. and;
Similarly, an adjusting arm for returning to neutral is pivotally attached to the fuselage so as to swing around a swinging fulcrum of an arm support shaft parallel to the operating axis, and is constantly provided with spring pressure in the direction of returning the pedal to neutral. and a pair of idle rollers for forward movement control that come into contact with the adjustment arm during a forward operation by pressing the pedal, and a pair of idle rollers for reverse movement control that also come into contact with the adjustment arm during a reverse operation. It is characterized in that when the pedal is in the neutral position, both of the floating rollers are held in such a relationship that they come into contact with the adjusting arm at the same time.

<Example> Hereinafter, the specific configuration of the present invention will be described in detail based on the illustrated example. FIGS. 1 to 4 represent the basic example of the present invention, and (10) is a tractor body; , an HST (not shown) is incorporated in the transmission system to the rear wheels inside the transmission case. (11) is an operating shaft that extends horizontally from the HST to the outside of the fuselage (10), and the operating shaft (11) is attached to the tip of the projecting end.
1) is fixedly mounted. The actuating arm (12) is configured to swing in the front-rear direction with its midway portion serving as a swing fulcrum (A) by the actuating shaft (11).

(13) is a pedal for switching between forward (F) and reverse (R), and is a pedal support shaft (4) that protrudes from the fuselage (10) in a fixed state parallel to the operating shaft (11). It is pivoted around the periphery so that it swings like a seesaw via a swing lever (not shown), and the forward movement (F) of the aircraft (IO)
At times, the front position is stepped downward, and when moving backward (R), the rear position is stepped downward. (15) is the middle part of the pedal (13) and the above-mentioned operating arm (12)
It is a rod of a certain length that pivotally connects the lower part of the holder, and although the details are not shown, its length can be pre-arranged eight times to make it longer or shorter.

Further, (16) is a forward control idler roller that is pivotally supported at the upper position of the operating arm (12), and (17) is a reverse motion roller that is also pivotally supported at the lower position of the arm (12).
This is a commonly used floating roller, and a pair of upper and lower floating rollers (16) and (17) face each other across the swinging fulcrum (A) in the middle.

In that case, the pivot point C of the forward control idler roller (16)
The mutual distance (b) between the swing support point (A) of the actuating arm (12) and the swing support point (A) of the operating arm (12) is the same (the distance between the swing support point (A) and the pivot support point (C) of the reverse control idler roller (17)). Mutual spacing M
(2) can be set to be substantially the same as (2), but in particular, in the illustrated example, the amount of expansion and contraction of the neutral return spring (described later) or the amount of swing of the adjustment arm pulled by the spring are set in the forward (F) operation and in the reverse (R) operation. )ti In order to keep the honorable mentions mutually the same, the former interval distance (b) is set to be longer than the latter interval distance (a).

Furthermore, (1B) is an adjustment arm for returning to neutrality, and L
It has a bent shape, and at the boundary between the vertical half (19) and the almost horizontal other half (20), the pedal shaft (I4) is opened from the fuselage (10) in the same way as the pedal shaft (I4). The arm support shaft (21) is pivotally connected to a protruding arm support shaft (21) in a fixed state. The supporting shaft (21) is also the operating shaft (11) of the HST.
), and the adjustment arm (18) makes a singing motion using this as a swing fulcrum (D). (
22) is a tension coil spring for returning to neutrality which is connected and tensioned between the other half (2o) of the adjustment arm (18) and the fuselage (10); The portion (19) is always pressed forward.

In that case, the special half part (19) of the adjustment arm (18) which was in charge of the pushing force in the neutral (N) return direction,
Both idler rollers (16) (1) of the said operating arm (12)
7), and is set so that it contacts both the idler rollers (16) and (17) simultaneously and equally in its neutral (N) state.

Moreover, the mutual distance (y) between the swing fulcrum (D) of the adjustment arm (18) and the shaft fulcrum (B) of the forward control idler roller (16) is the same as that between the swing fulcrum (D) and the reverse control The size is set to be longer than the mutual distance (x) between the idler roller (17) and the shaft fulcrum (C), and therefore, even though a common coil spring (22) for returning to neutral is used, The adjusting arm (18) allows the pressing force to be weakly applied to the forward control idler roller (16) and strongly applied to the backward control idler roller (17).

Namely, 1. When operating the aircraft (10) forward CF) and backward (R)
During operation, the spacing distance (x) between the floating rollers (16) and (17) is set so that the same pressing force for returning to neutrality is applied by the coil spring (22) and the amount of expansion and contraction of the coil spring (22) is the same. ) (y), and the other half ( The length of the coil spring (20) is (z), and the size ratio of the above distance (x) (y) is used to calculate the length of the coil spring (22).
) has a constant action length L), and the force acting on the forward control idler roller (16) and the reverse control idler roller (17) has the following relationship. It is set to be maintained.

W - ) is of course set in advance to a value that provides good neutral brake feeling, as the return load greater than the shaft torque value acting toward the speed increasing side.

In this regard, in the above basic embodiments shown in FIGS. 2 to 4, the adjustment arm (18) itself is defined as an L-shaped bent type, but if the configuration does not deviate from the above spirit, then the adjustment arm (18) shown in FIG. As shown in the first modified embodiment, the adjustment arm (18) may be formed in a straight shape, so to speak, or in other shapes.

In addition, in the above basic embodiment, a pair of upper and lower idle rollers (16
) (17) are set to be the same size, but the 6th
As in the second modified embodiment shown in the figure, the frequently used forward control idler roller (16) is replaced with the reverse control idler roller (16).
It is also possible to balance durability and cost by creating a larger diameter than 17), and even if the size is changed in this way, both idle rollers (
+6) It goes without saying that (17) is brought into contact with the adjustment arm (18) at the time of -graduation.

In any case, the contact action is caused by an oscillating roller (1
B) Since the shape of (17) is adopted, uneven wear and rubbing resistance can be effectively eliminated, and durability and stability can be significantly improved.

<Function> Based on the basic embodiment described above, the function will be explained next. When the front part of the pedal (13) is depressed, the lower part of the actuating arm (12) moves as shown in Fig. 3. Only the forward control idler roller (16), which is pulled forward by the rod (15) and pivotally supported on the upper part thereof, comes into contact with the adjustment arm (18), and its coil spring (22) causes pressure to return to the neutral direction. As a result, the HST maintains a forward (F) speed state corresponding to the amount of depression of the pedal (13). In that case, the return pressure acting on the forward control idler roller (16) is relatively weak due to the above configuration, so it is possible to easily shift gears during frequently used forward load work. can.

Conversely, when the rear position of the pedal (13) is depressed and operated, the lower part of the actuating arm (12) moves to the rod (
Only another reverse control idler roller (17), which is pushed rearward by the coil bar 2 (22) and is pivoted at its lower part, comes into contact with the adjustment arm (18), and is also subjected to the return pressure in the neutral direction by the coil bar 2 (22). The HST is maintained at a reverse (R) speed state corresponding to the amount of depression of the pedal (13). Under this condition, the return pressure applied to the reverse control idler roller (17) is strong as described in 1), so it is possible to prevent a sudden start in the reverse direction during general driving. .

In the neutral (N) state where the above-mentioned depression is completely released, as shown in Fig. 2, the so-called two-point support action is applied to both the idler rollers (16) and (17) for forward control and reverse control. The adjustment arm (18) comes into contact with this, and the coil spring (22) applies a constant force to it, resulting in an extremely stable and firm posture of the pedal (13), which reduces the extremely narrow HST. It can correspond to the neutral range.

<Effects of the Invention> As described above, in the present invention, as a neutral return mechanism for the operating pedal in a tractor equipped with a hydraulic continuously variable transmission, the operating shaft of the HST (
11), an actuation arm (12) attached so as to be able to rotate together with this as a swinging fulcrum (A); its actuation axis (
a pedal (13) pivotally attached to the body (10) so as to swing around a pedal support shaft (14) parallel to the pedal (11), and pivotally connected by an actuation arm (12) and a rod (15); The arm support shaft (21) is also parallel to the operating shaft (11).
A neutral return adjustment arm (18) is pivoted to the aircraft body (10) so as to swing around the swing fulcrum (D), and is constantly applied with spring pressure in the direction of returning the pedal (13) to neutral.
), and an idler roller (16) for forward movement control that comes into contact with the adjustment arm (18) when the forward movement CF) is operated by pressing the pedal (13), and a reverse movement (CF).
A pair of idle rollers (17) for reverse control that come into contact with the adjusting arm (18) when operating the pedal (R) are each pivotally supported on the operating arm (12), and the pedal (13) is in the neutral (N) position.
When it is in the position, both idler rollers (16) (
17) and the adjustment arm (18) at the same time, the neutral state can be maintained stably and firmly at all times, and the narrow neutral range of HST can also be blamed. , by means of the two separate floating rollers (16) (17), the load acting on them can also be easily varied.

Moreover, since the contact action with the adjustment arm (18) is carried out depending on the form of the floating rollers (16) and (17), the sliding resistance and uneven wear can be reduced compared to a rigid member that does not move. This means that the durability can be significantly improved while effectively eliminating the problem.

Also, especially as in the illustrated embodiment, both the rollers (16)
(17) is the swing fulcrum (A
), and the mutual distance (b) between the pivot support point (B) and the swing support point (A) of the forward control idler roller (16) is set to the swing support point (A). The pivot point (B) of the forward control idler roller (16) and the adjustment arm ( The mutual distance (y) between the swing fulcrum (D) of 18) and the swing fulcrum (D) of the swing fulcrum (D)
If the dimension is set to be longer than the mutual distance (x) with the shaft fulcrum (C) in 7), it will be possible to use it during heavy load work in forward movement (F), which is frequently used, and on the other hand, in reverse movement (R), which is generally lower. The pressure control by the neutral return spring (22) is automatically adjusted during driving, and the spring action on the pedal (13) and its swing link mechanism can be averaged, so that the front This can be said to be of great practical benefit, as it provides an unchanging pedal depression feeling and neutral brake feeling when going backwards, and also prevents dangerous sudden starts in the reverse direction.

[Brief explanation of drawings]

Fig. 1 is a schematic side view of the tractor according to the present invention, Fig. 2 is an enlarged side view of the tractor in a neutral operating state, with its main parts extracted and schematically shown, and Fig. 3.4 is a schematic side view of a tractor according to the present invention in a neutral operating state. 5.6 is an enlarged side view of the modified embodiment 1.2 corresponding to FIG. 2, and FIG. 7 is a line graph showing the return torque acting on the operating shaft of the HST. (10)...Tractor body (11)...Operating shaft (12)...Operating arm (13)...Pedal (14)...Pedal support shaft (15)... Rod (16)... Idle roller for forward control (17)...
...Idle roller for reverse movement control (18) ...Adjustment arm (21) ...Arm support shaft (22) ...Coil spring (A) (D) ...Owing support (B) (C) ... Pivot support point (E) ... Spring attachment point (a) (b) ... Spacing distance (x) (y) ... Spacing distance Patent applicant Toyosha Co., Ltd. Agent Patent Attorney Kenji Yamashita Procedural Amendment September 6, 1985 Patent Application No. 179030 of 1985 2 Title of Invention Neutral Return Mechanism for Operating Pedal in Tractor Equipped with Hydrodynamic Continuously Variable Transmission 3 Amended [Relationship with the case] Patent applicant: Toyosha Co., Ltd. 4, 16-55 Jojo Teramachi, Kadoma-shi, Osaka Prefecture; Agent: “Sanko Building (7154), 1-1 Karahorimachi, Tennoji-ku, Osaka; Patent attorney Kenji Yamashita; 5. Date of amendment order
J spontaneous 6, subject to correction

Claims (1)

[Claims] 1. An operating arm (12) attached to the operating shaft (11) of the HST mounted on the tractor body (10) so as to be able to rotate integrally with the operating shaft (11) as a swinging fulcrum (A). is pivoted to the fuselage (10) so as to be able to swing around a pedal support shaft (14) parallel to the operating axis (11), and the operating arm (12)
) and a pedal (13) pivotally connected by a rod (15).
), and is also pivoted to the fuselage (10) so as to swing around the swinging fulcrum (D) of the arm support shaft (21), which is also parallel to the operating shaft (11), and the pedal (13) is always kept in the neutral position. Adjustment arm (1) for neutral return to which spring pressure is applied in the direction of return.
8), an idler roller (16) for forward control that comes into contact with the adjustment arm (18) during a forward operation by depressing the pedal (13), and also comes into contact with the adjustment arm (18) during a reverse operation. A pair of idle rollers (17) for reverse movement control are each pivotally supported on the actuation arm (12),
3) when in neutral, both idle rollers (16) (17)
A neutral return mechanism for an operation pedal in a tractor equipped with a hydraulic continuously variable transmission, characterized in that the control arm (18) is brought into contact with the adjustment arm (18) at the same time. 2. The forward control idler roller (16) and the backward control idler roller (17) are arranged to face each other as an upper and lower pair across the swinging fulcrum (A) of the operating arm (12), and the forward control idler roller ( 16) and the pivot point (D) of the adjustment arm (18).
) is also set to be longer than the mutual distance (x) between the swing fulcrum (D) and the shaft fulcrum (C) of the backward control idler roller (17), so that the forward control idler roller (16) Claim 1, characterized in that the spring pressure acting on the neutral return direction is set to be weaker than the spring pressure acting on the reverse control idler roller (17) during reverse operation. Neutral return mechanism for operating pedals on tractors equipped with hydraulic continuously variable transmissions. 3. The mutual distance (b) between the swing fulcrum (A) of the operating arm (12) and the shaft fulcrum (B) of the idle roller (16) for forward movement control is the same as that between the swing fulcrum (A) and the axis support point (B) for backward movement control. The adjustment arm (
18) The operating pedal for a tractor equipped with a hydraulic continuously variable transmission according to claim 1, characterized in that the amount of rocking in step 18) is set to be substantially the same as that during reverse operation. neutral return mechanism. 4. A tractor equipped with a hydraulic continuously variable transmission according to claim 1, characterized in that the forward control idler roller (16) is formed to have a larger diameter than the reverse control idler roller (17). Neutral return mechanism for operating pedals.