JP2695513B2 - Work vehicle speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a link mechanism between a gear shift operation tool that can be held at an arbitrary position within a gear shift operation range and a continuously variable transmission for traveling. An elastic interchange part is provided to allow the shift operation device to move to the high speed side in a state where the continuously variable transmission is at the high speed side of the speed change range, and the speed change actuator is
When a member closer to the speed change operation tool than the elastic interchange part is operated, the load detection means for detecting an engine load and the detected engine load of the load detection means become larger than a set value. Is a work vehicle provided with a control means for obtaining an operation amount of the actuator for decelerating the transmission and operating the actuator with the operation amount to automatically decelerate the transmission. Vehicle speed control device.

[Conventional technology]

The vehicle speed control device for a work vehicle of this type, for example, when the engine is overloaded, without performing feedback control for decelerating to the target vehicle speed set corresponding to the detected vehicle speed, By determining the operation amount of the actuator for deceleration operation and operating the actuator with the operation amount to automatically decelerate the transmission, the response delay of the control system can be reduced. Therefore, although the transmission is configured so that the actuator can automatically perform the gear shifting operation, the gear shifting operation tool that can be held at any position within the gear shifting operation range can be operated manually so that the gear shifting operation can be performed manually. It is linked to the device.

However, since it is difficult to completely match the operating range of the speed change operation tool and the operation range of the speed change device, the speed change device is set to the high speed side of the speed change range during the linkage mechanism between the speed change operation tool and the speed change device. An elastic accommodation portion is provided to allow the shift operation tool to move to the high speed side even when the speed is limited, and the gear shift actuator operates a member on the gear operation side of the elastic accommodation portion.

Conventionally, vehicle speed detection means for detecting the vehicle speed based on the output speed of the transmission and the input speed to the traveling device is provided,
The operation amount is calculated according to the difference between the vehicle speed detected by the vehicle speed detection means and a preset target vehicle speed to be decelerated.

[Problems to be solved by the invention]

When the continuously variable transmission is adapted to operate the shift operation tool side with respect to the elastic interchange portion which allows the shift operation tool to shift to the high speed side in a state where the speed change range is at the high speed side limit, the actuator is operated. In the condition that the elastic interchange part operates,
Even if the actuator for gear shifting is operated with an operation amount corresponding to the difference between the detected vehicle speed and the target vehicle speed to be decelerated, there is a possibility that the actual deceleration amount cannot be reduced.

Therefore, when the speed change operation tool is operated within the range in which the elastic accommodation portion operates and the detected vehicle speed reaches the upper limit of the high speed side, the speed change operation tool is located at the operation upper end that is higher than the upper limit of the speed change range. However, it is conceivable to operate the actuator with a certain amount of deceleration that allows deceleration to the target vehicle speed.However, if the gear shift operation tool is near the limit of the gear shift range of the transmission, the deceleration amount is reversed. There is a risk of becoming excessive.
Similarly, if the actuation amount of the actuator is set to the appropriate actuation amount required to decelerate to the target vehicle speed when the gear shift operation tool is near the limit of the gear shift range of the transmission, if the gear shift operation tool is at the upper end of the operation, it will be reversed. Therefore, the deceleration amount may be insufficient. In other words, when the elastic interchange part is in a working state,
If the actuator is operated with a constant operation amount, the deceleration amount may be excessive or insufficient.

The present invention has been made in view of the above circumstances,
The purpose is to decelerate at an appropriate deceleration amount even when the elastic interchange part that allows the shift operation tool to move to the high speed side is operating in the state where the speed change range of the transmission is at the high speed side. To be able to do it.

[Means for solving the problem]

In the vehicle speed control device for a work vehicle according to the present invention, the continuously variable transmission is provided in a gear shift range within a linkage mechanism of a gear shift operation tool that can be held at an arbitrary position within a gear shift operation range and a traveling continuously variable transmission. Is provided with an elastic interchange section that allows the shift operation tool to move to the high speed side in a state where the speed change actuator is in a limit state, and a speed change actuator operates a member on the shift operation tool side with respect to the elastic interchange section. And load detection means for detecting the engine load, and actuation of the actuator for decelerating the transmission when the detected engine load of the load detection means exceeds a set value. A control means for determining an amount and operating the actuator with the operating amount to automatically decelerate the transmission is provided. The characteristic configuration is as follows.

That is, a position detecting means for detecting an operation position of the speed change operation tool is provided, and the control means controls the current operation position of the speed change operation tool detected by the position detection means and a preset target position for deceleration. It is configured to obtain the actuation amount according to the difference between

(Operation)

The amount of actuation of the actuator is obtained according to the difference between the current operating position of the gear shift operating device detected by the position detecting means and the preset target position for deceleration, and the actuator is actuated by the amount of actuation to obtain elasticity. It is possible to accurately operate the speed change operation tool to the target position for deceleration regardless of whether or not the interchange portion is operating.

〔The invention's effect〕

Therefore, regardless of whether or not the elastic accommodation portion is operating, the gear shifting operation can be properly decelerated to the state where the speed change operation tool is positioned at the target position for deceleration. Even if the vehicle is in a state of being decelerated, it is possible to decelerate with an appropriate deceleration amount.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a combine vehicle speed control device will be described with reference to the drawings.

As shown in FIG. 1, the output of the engine (E) is transmitted to each of the threshing device (1) and the mowing section (2) as working devices, and the hydraulic continuously variable transmission (3) for traveling is also used. The output of the transmission (3) is also transmitted to the mission section (5) of the crawler traveling device (4). However, although not described in detail, transmission between the components is performed by a belt or the like.

Then, a load sensor of the engine (E) is determined on the basis of the information of the rotation speed sensor (S ₁ ) for detecting the rotation speed of the engine (E) and the rotation speed sensor (S ₁ ) to determine the engine load. Is greater than the set value, the operation amount of the actuator (8) for decelerating the transmission (3) is obtained, and the actuator (8) is operated by the operation amount to operate the actuator (8). A control device (6) as a control means for automatically decelerating the transmission device (3) is provided.

The electric transmission (8) is configured so that the transmission (3) can be operated by both a manually operated speed change lever (7) as a speed change operation tool and an electric motor (8) as a speed change actuator. ) Is linked to a rod (9) as a linking mechanism between the speed change lever (7) and the speed change device (3) through a friction holding mechanism (10). That is, the manual gear shifting operation is prioritized over the gear shifting operation by the electric motor (8), but the gear shifting operation can be automatically performed.

Then, the shift lever (7) is held at an arbitrary position within the shift operation range by utilizing the friction holding mechanism (10).

Further, the gear shift lever (7) in the state in which the gear shift device (3) is at the high speed side limit (A) of the gear shift range in the linkage mechanism of the gear shift lever (7) and the gear shift device (3). The elastic upper end (B) is provided with an elastic accommodation portion (11) for allowing the shift of the gear shifter to the high speed side, and the shift lever (7) is at a higher speed side than the high speed side limit (A) of the shift range.
Can be operated up to. In addition, in FIG. 1, (1
2) is a guide plate for the speed change lever (7).

If the elastic interchange part (11) is further described, the second
As shown in the drawing, a cylinder (14) having a coil spring (13) initially compressed therein is provided in an intermediate portion of the rod (9) as the linkage mechanism. However, the rod (9) is connected to a cylinder side rod (9a) connected to the speed change lever (7) and a piston side rod (9b) connected to the speed change device (3). Split up,
The piston side rod (9b) in the cylinder (14)
Are connected in the state of being installed.

The initial setting pressure of the coil spring (13) is weaker than the holding force of the speed change lever (7) by the friction holding mechanism (10), and the speed change device (3) is set to the high speed side limit (A). It is set to be larger than the operating force required for shifting operation at a lower speed side.

That is, the coil spring (13) is not compressed and the cylinder side rod (9a) and the piston side rod (at the low speed side of the speed change range limit (A) of the transmission (3) are not compressed. 9b) is configured so as to act as a rigid body without being shortened so that the elastic interchange part (11) is in a non-actuated state. Accordingly, while allowing the operating force of the speed change lever (7) to be transmitted to the speed change device (3), the speed change lever (7) can be transmitted even after the speed change device (3) reaches the high speed side limit (A). 7) can be operated to a higher speed side until it reaches the operable upper end (B). The electric motor (8) operates a rod (9a) on the cylinder side linked to the shift lever (7) as a member on the shift operation tool side.

Therefore, as shown by the broken line in FIG. 3, while the operation position of the speed change lever (7) is between the upper limit (A) on the high speed side and the operation upper end (B), the elastic interchange part (11). ) Is actuated to absorb the operation of the speed change lever (7) and the electric motor (8), the speed change device (3) is maintained at the upper limit (A) of the speed change range, and the vehicle speed can be changed. The maximum vehicle speed (V ₁ ) will not change.

In addition, since the electric motor (8) operates the cylinder side (9a) of the rod (9), which is a member closer to the speed change operation tool than the elastic interchange portion (11). , The electric motor (8) is operated when the speed change lever (7) is between the high speed side limit (A) and the operation upper end (B) and the elastic interchange portion (11) is operating. Even if it is done, the elastic interchange part (11) absorbs the operation and the transmission (3) is not decelerated.

Therefore, a position sensor (S ₂ ) as a position detecting means for detecting the operation position of the gear shift lever (7) is provided, and the control device (6) controls the gear shift lever (S ₂ ) to detect the gear shift lever (S ₂ ). The operation amount is obtained according to the difference between the current operation position (s) in (7) and the preset target position for deceleration (s ₀ ), and the speed change lever (7) is configured to allow the elastic interchange. Even if the portion (11) is between the high speed side limit (A) and the operation upper end (B), when the engine load becomes larger than the set value, the gear shift lever (7) is moved to the target position ( It is possible to operate it up to s ₀ ).

 Next, the detection of the engine load will be described.

The number of revolutions of the engine (E) is inversely proportional to the load so that it becomes lower as the load becomes heavier. Therefore, when the rotation speed (N) detected by the rotation speed sensor (S ₁ ) becomes lower than the set rotation speed (N ₁ ) corresponding to the set value for determining the magnitude of the engine load, the engine load is reduced. It is determined that the value is larger than the set value. That is, the rotation speed sensor (S ₁ ) corresponds to load detecting means for detecting the engine load.

When the engine load becomes larger than the set value and the engine speed (N) becomes lower than the set speed (N ₁ ), the electric motor (8) decelerates the transmission (3). By operating it, the traveling load is directly reduced, and indirectly, the working load is reduced by decelerating the working speed so that the engine load is maintained below the set value.

In this embodiment, the operation amount of the electric motor (8) is set as the time for continuously driving the electric motor (8) by one deceleration operation, that is, the operation time (T) of the actuator. There is.

Then, as shown in the following formula, the operating time (T)
Corresponds to the current operating position (s) of the speed change lever (7) detected by the position sensor (S ₂ ) and a preset target vehicle speed (V ₀ ) to be decelerated (see FIG. 3). It is determined according to the difference between the gear shift lever (7) and the target position (s ₀ ).

T = k · (s−s ₀ ) In the above equation, k is a constant.

That is, by obtaining the operation amount according to the difference between the current operation position (s) of the speed change lever (7) detected by the position sensor (S ₂ ) and the target position (s ₀ ), The speed change device (3) can be decelerated until the speed change lever (7) is positioned at the target position (s ₀ ) regardless of the operating state of the elastic accommodation portion (11). .

(Another embodiment)

In the above-described embodiment, the case where the engine load is detected based on the rotation speed of the engine (E) has been illustrated.
For example, it may be detected based on a variation in the output torque of the engine (E), etc., and the specific configuration of the load detecting means can be variously changed.

Further, in the above embodiment, the case where the present invention is applied to the combine is illustrated, but the present invention can be applied to the vehicle speed control device of various work vehicles, and the specific configurations of the respective parts can be variously changed.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of the drawings]

The drawings show an embodiment of a vehicle speed control device for a work vehicle according to the present invention. FIG. 1 is a block diagram of a control configuration, FIG. 2 is an explanatory view of an elastic accommodation portion, and FIG. It is explanatory drawing of the relationship of a position. (S ₁ ) …… Load detection means, (S ₂ ) …… Position detection means,
(3) ... continuously variable transmission, (6) ... control means, (7)
...... Gear change operation tool, (8) ...... Gear change actuator,
(11) …… Elastic interchange part.

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display F16H 59:44

Claims (1)

(57) [Claims] 1. A continuously variable transmission (3) in a linkage mechanism between a continuously variable transmission (3) for traveling and a gear shift operation tool (7) which can be held at an arbitrary position within an operation range for gear shifting. An elastic interchange part (11) is provided to allow the shift operation tool (7) to move to the high speed side in a state where the speed change range is at the high speed side, and the speed change actuator (8) includes the elastic interchange part. Load detecting means (S ₁ ) for detecting an engine load, which is provided so as to operate a member closer to the gear shift operation tool than the section (11)
And when the detected engine load of the load detecting means (S ₁ ) becomes larger than the set value, the operating amount of the actuator (8) for decelerating the transmission (3) is calculated. A vehicle speed control device for a work vehicle, comprising: a control means (6) for automatically decelerating the transmission (3) by operating the actuator (8) with the operation amount thereof. Position detection means (S ₂ ) for detecting the operation position of the operation tool (7) is provided, and the control means (6) controls the shift operation tool (7) detected by the position detection means (S ₂ ). A vehicle speed control device for a work vehicle configured to obtain the operation amount according to a difference between a current operation position and a preset target position for deceleration.