JP5160174B2 - Travel speed control device - Google Patents

Description

  The present invention relates to a traveling speed operation device applied to a working vehicle such as a tractor in which an HST is inserted in a traveling system transmission path, and more specifically, a shift operation mechanism for operating the HST and the shift operation mechanism. A cruise operation mechanism for switching between a cruise state in which the HST output is held constant by holding at an arbitrary shift position and a cruise release state in which the cruise state is canceled, and a brake actuator in a traveling brake device provided in the work vehicle are operated. The present invention relates to a traveling speed operation device provided with a brake operation mechanism.

  To operate a speed change operation mechanism that operates an output adjustment member in the HST inserted in the travel system transmission path, a cruise operation mechanism that can hold the speed change operation mechanism at an arbitrary operation position, and a brake actuator in the travel brake device. A brake operation mechanism, and in addition to a release operation to the cruise operation mechanism, the cruise operation by the cruise operation mechanism is a shift operation to the shift operation member in the shift operation mechanism or a brake operation member in the brake operation mechanism. BACKGROUND ART A traveling speed operation device configured to be released even by a brake operation is conventionally known (for example, see Patent Document 1 below).

  The conventional travel speed operation device changes the travel speed via the speed change operation mechanism or the brake operation when the work vehicle is held in a cruise state (constant speed travel state) by the cruise operation mechanism. This is useful in that the cruise state can be canceled without operating the cruise operation mechanism when the traveling speed is reduced via the mechanism.

However, in the conventional travel speed operation device, since the speed change operation mechanism and the brake operation mechanism are completely independent, there is a possibility that the output operation of the HST and the brake operation of the travel brake device may occur simultaneously. It was.
That is, in the conventional traveling speed operation device, the shift operation mechanism can be operated to the speed increasing side even when the traveling brake device is operated via the brake operation mechanism. For this reason, when the shift operation mechanism is operated to the speed increasing side for some reason when the travel brake device is operated, the HST performs the braking force applied to the travel system transmission path by the travel brake device. A driving force is output to the traveling transmission path.
Such an operating state may cause wear and damage to the traveling brake device and / or the HST.
JP 2007-55281 A

  The present invention has been made in view of the prior art, and in a traveling speed operation device including a speed change operation mechanism, a cruise operation mechanism, and a brake operation mechanism, the brake operation state of the traveling brake device and the output state of the HST are simultaneously performed. An object of the present invention is to provide a traveling speed operation device that can prevent the occurrence of the occurrence.

In order to achieve the above object, the present invention provides a speed change operation mechanism for operating an output adjustment member of an HST, which is a maneuverable speed change operation member, and an axis line corresponding to the maneuver to the speed change operation member. A speed change operation mechanism having a speed change operation shaft that rotates around, a speed change operation member that is supported by the speed change operation shaft so as not to rotate relative to the speed change operation shaft, and an HST operation link that operatively connects the speed change operation member and the output adjustment member; A cruise operation mechanism for switching between a cruise state in which the shift operation mechanism is held at a predetermined operation position or a cruise release state in which the cruise state is canceled, and a manually operated cruise operation member and the shift operation member A plurality of ratchet teeth provided and a cruise position or a front where the ratchet teeth engage with the ratchet teeth around a cruise axis in response to an artificial operation on the cruise operation member. A cruise operation mechanism having a cruise member capable of taking a cruise release position in which the engagement with the ratchet teeth is released, and a cruise release urging member that urges the cruise member toward the cruise release position; A brake operation mechanism for operating a brake actuator of a brake device, wherein a brake operation member that can be manually operated, a brake operation shaft that rotates about an axis in response to an artificial operation to the brake operation member, and the brake operation A brake actuating member supported by the shaft so as not to rotate relative to the shaft; a brake link for operatively coupling the brake actuating member and the brake actuator; and a brake release for urging the brake actuating member toward the brake release position. A travel speed operating device comprising a brake operating mechanism having a biasing member, A brake interlocking arm supported on the brake operation shaft so as not to rotate relative to the brake operation shaft, wherein the cruise member located at the cruise position is moved around the cruise shaft in response to an operation from the brake release position to the brake operation position of the brake operation member. A brake interlocking arm having a cruise canceling arm portion that is pushed toward the cruise canceling position, and a shift interlocking arm that is supported so as to be swingable around a pivot shaft parallel to the shift operation shaft. Provided is a traveling speed operation device including a shift interlocking arm provided with a cam part and a brake interlocking cam part.
The shift operation member is further separated from the shift operation shaft toward the one side and the other side in the circumferential direction with respect to the shift operation shaft with the deepest portion closest to the shift operation shaft interposed therebetween. A shift interlocking cam surface including a pair of inclined portions that engage with the shift interlocking cam portion when the operation member is located at the non-neutral position is provided.
The shift interlock arm is biased about the pivot shaft by a shift interlock arm biasing member in a direction in which the shift interlock cam portion engages with the shift interlock cam surface.
The brake interlocking arm is further provided with a neutral groove for holding the shift interlocking arm in the neutral position by engaging the brake interlocking cam portion when the brake operating member is positioned at the brake operating position. It has been.

Preferably, the shift interlocking cam part and the brake interlocking cam part are arranged coaxially.
Preferably, the brake interlocking arm includes the brake interlocking cam portion when the brake operating member is operated from the brake releasing position to the brake operating position in a state where the speed change operating member is in the non-neutral position. A guide surface is provided for guiding the guide to the neutral groove.

In the various configurations, a neutral switch for detecting a neutral state of the HST may be preferably provided.
The neutral switch is configured to detect whether or not the shift interlocking arm is positioned at a neutral position.

In the various configurations, preferably, the first end portion is connected to the brake operation member, and the second end portion is rotatable about a differential lock operation shaft parallel to the brake operation shaft in order to operate the differential lock mechanism. A rigid link member operatively connected to the differential lock operating member may be provided.
The brake actuating member includes a proximity end portion on a side close to the differential lock operation member, a separation end portion on a side separated from the differential lock operation member, and an intermediate communicating between the proximity end portion and the separation end portion. A long hole having a portion is provided.
The link member is configured such that when the differential lock operation member is positioned at the differential lock release position in a state where the brake operation member is positioned at the brake release position, the first end portion is at the proximity end portion of the elongated hole. When the differential lock operating member is positioned at the differential lock position with the brake actuating member positioned at the brake release position, the first end portion is positioned at the separation end portion of the elongated hole. Configured as follows.

As described above, the travel speed operating device according to the present invention includes the brake interlocking arm that interlocks with the brake operating member and the shift interlocking arm that interlocks with the speed change operating member. The shift interlocking arm is provided with a shift interlocking cam portion and a brake interlocking cam portion. The shift operation member that is linked to the shift operation member is provided with a shift interlock cam surface that includes a pair of inclined portions that engage with the shift interlock cam portion. The brake interlocking arm is further provided with a neutral groove for holding the shift interlocking arm in the neutral position by engaging the brake interlocking cam portion when the brake operating member is positioned at the brake operating position.
Therefore, it is possible to effectively prevent the HST from entering the output state via the shift operation mechanism even though the traveling brake device is in a brake operation state via the brake operation mechanism. Wear and damage of the traveling brake device can be effectively prevented.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a side view of a working vehicle 1 to which a traveling speed operation device 100 according to the present embodiment is applied.
2 and 3 are front perspective views of the traveling speed operation device 100 according to the present embodiment. 2 and 3 are perspective views viewed from the left side and the right side, respectively, with reference to the vehicle forward direction.

  As shown in FIGS. 1 to 3, the working vehicle 1 includes a vehicle frame 10, a drive source 20 disposed on the front side of the vehicle frame 10, an HST 30 operatively connected to the drive source 20, a vehicle A mission case 40 connected to the rear side of the frame 10 and a traveling brake device (not shown) provided in the mission case 40 are provided.

  2 and 3, the HST 30 includes a pump shaft 31 that is operatively connected to the drive source 10, a hydraulic pump body (not shown) that is supported by the pump shaft 31 so as not to rotate relative thereto, A hydraulic motor main body (not shown) fluidly connected to the hydraulic pump main body, a motor shaft 32 that supports the hydraulic motor main body so as not to be relatively rotatable, and the hydraulic pump main body and the hydraulic motor main body are accommodated integrally or individually. The HST case 33 is provided.

In the HST 30, at least one of the hydraulic pump main body and the hydraulic motor main body is a variable displacement type, and the hydraulic pump main body and / or the hydraulic motor main body (hereinafter referred to as a variable displacement member) that is a variable displacement type. ), The output rotational speed from the motor shaft 31 with respect to the input rotational speed to the pump shaft 31 is changed.
Accordingly, the HST 30 includes an output adjustment member that changes the suction / discharge amount of the variable volume member in addition to the above-described configuration.
The output adjusting member may include, for example, a movable swash plate (not shown) that changes the volume of the variable volume member, and a control shaft 35 that tilts the movable swash plate.

In the illustrated embodiment, both the hydraulic pump body and the hydraulic motor body are variable displacement types.
Therefore, the HST 30 includes a pump-side output adjustment member and a motor-side output adjustment member as the output adjustment member.

The pump-side output adjusting member includes a neutral state in which the suction / discharge amount of the hydraulic pump body is zero, a forward state in which the suction / discharge amount of the hydraulic pump body is changed in the forward direction of the work vehicle, and the hydraulic pressure The pump body is configured to be in a reverse state in which the suction / discharge amount of the pump body is changed in the reverse direction of the working vehicle.
On the other hand, the motor-side output adjusting member rotates the hydraulic motor main body at a high speed with respect to a predetermined hydraulic oil amount from the hydraulic pump main body, and rotates the hydraulic motor main body at a low speed with respect to the predetermined hydraulic oil amount. It is comprised so that the low-speed state to take can be taken.

Further, the work vehicle 1 includes the travel speed operation device 100.
As shown in FIGS. 2 and 3, the traveling speed operation device 100 holds the shift operation mechanism 200 for operating the HST 30, and holds the shift operation mechanism 200 at an arbitrary shift position to keep the HST output constant. A cruise operation mechanism 300 that switches between a cruise state that is held by the vehicle and a cruise release state that is released from the cruise state, and a brake operation mechanism 400 that operates a brake actuator (not shown) in the traveling brake device. .

First, the shift operation mechanism 200 will be described.
The speed change operation mechanism 200 includes a speed change operation member 210 that can be manually operated, a speed change operation shaft 220 that rotates about an axis in response to an artificial operation on the speed change operation member 210, and a speed change operation shaft 220 that is not rotatable relative to the speed change operation shaft 220. A shift operation member 230 that is supported, and an HST operation link 240 that operatively connects the transmission operation member 230 and the output adjustment member are provided.
In the present embodiment, the shift operation mechanism 200 is configured to artificially operate the pump-side output adjustment member configured to be able to take a forward state, a neutral state, or a reverse state among the output adjustment members. It is configured.

FIG. 4 shows a partially enlarged perspective view of the traveling speed operation device 100.
As shown in FIGS. 2 to 4, the speed change operation shaft 220 is supported so as to be rotatable about an axis in a state along the vehicle width direction.
In the present embodiment, the traveling speed operation device 100 has a fixed plate 15 that is fixedly supported directly or indirectly on the vehicle frame 10, and the speed change operation shaft 220 is connected to the fixed plate 15. It is inserted in the supported cylindrical member 16 so as to be rotatable around its axis.

As described above, the shift operation mechanism 200 is configured to operate the pump-side output adjustment member that can be in a forward state, a neutral state, or a reverse state.
Therefore, the speed change operation member 210 is configured to be able to operate the pump side output adjusting member forward and backward.

Specifically, as shown in FIGS. 2 and 3, the speed change operation member 210 includes a forward pedal 210F that acts as a forward operation member, a reverse pedal 210R that acts as a reverse operation member, and a lower end portion that is A shift arm 211 is supported by the shift operation shaft 220 so as not to rotate relative to the shift operation shaft 220, and supports the forward pedal 210F and the reverse pedal 210R at the upper end.
With this configuration, when the forward pedal 210F is depressed, the speed change operation shaft 220 rotates to one side around the axis (counterclockwise in the left side view) via the speed change arm 211, and the reverse pedal 210R is When the stepping operation is performed, the speed change operation shaft 220 rotates about the axis to the other side (clockwise in the left side view) via the speed change arm 211.
In the illustrated embodiment, the speed change operating member 210 has a seesaw pedal in which the forward pedal 210F and the reverse pedal 210R are integrally formed.

The speed change operating member 230 includes a radial inner region 231 that is supported on the speed change operation shaft 220 so as not to be relatively rotatable, and a radial outer region 232 that extends radially outward from the radial inner end 231. Have.
In the present embodiment, as shown in FIG. 4, the speed change operating member 230 is a plate-like member.

The HST operation link 240 has one end connected to the radially outer region 232 of the speed change operating member 230 and the other end operatively connected to the control shaft 35 (see FIG. 3) of the pump side output adjusting member. ing.
In the present embodiment, as shown in FIG. 3, the pump-side output adjusting member is supported by the outer end portion of the control shaft 35 in a relatively non-rotatable manner in addition to the movable swash plate and the control shaft 35. The other end portion of the front end of the HST operation link 240 is connected to the control arm 36.

The shift operation mechanism 200 operates as follows.
In a state where no manual operation is performed on the HST operation member 210, the speed change operation mechanism 200 includes the following operation side neutral return mechanism provided in the travel speed operation device 100 and / or an output adjustment member of the HST 30 (this In the embodiment, the neutral state is maintained by an HST-side neutral return mechanism (not shown) provided incidentally to the pump-side output adjusting member.

  When the speed change operation member 210 is operated to the forward side against the urging force of the operation side neutral return mechanism and / or the HST side neutral return mechanism, the speed change operation shaft 220 rotates to one side around the axis. Accordingly, the speed change operating member 230 rotates to one side (forward side) around the axis of the speed change operation shaft 220. The HST operation link 240 is moved to one side in the axial direction by the rotational movement of the speed change actuating member 230 to the forward side, whereby the control shaft 35 is advanced in the forward direction around the axis via the control arm 36. Rotate to.

  On the contrary, when the speed change operation member 210 is operated to the reverse side against the biasing force of the operation side neutral return mechanism and / or the HST side neutral return mechanism, the speed change operation shaft 220 is rotated to the other side around the axis. Accordingly, the shift operating member 230 rotates to the other side (reverse side) around the axis of the shift operation shaft 220. The HST operation link 240 moves to the other side in the axial direction by the rotational movement of the speed change actuating member 230 to the reverse side, whereby the control shaft 35 moves in the reverse direction around the axis via the control arm 36. Rotate to.

Next, the cruise operation mechanism 300 will be described.
The cruise operation mechanism 300 includes a cruise state in which the shift operation mechanism 200 is maintained at a predetermined speed state in response to an operation on the manually operable cruise operation member 310, and a cruise release state in which the cruise state is released. It is comprised so that it can take.

  Specifically, as shown in FIGS. 2 to 4, the cruise operation mechanism 300 shifts the shift so that the cruise operation member 310 faces outward in the radial direction with reference to the axis of the cruise operation member 310 and the transmission operation shaft 220. A plurality of ratchet teeth 320 provided on the operating member 230, and a lock claw 331 that can selectively engage with one ratchet tooth among the plurality of ratchet teeth 320, and the lock claw around the cruise shaft 335. A cruise member 330 that can take a cruise position where 331 engages with the ratchet teeth 320 and a cruise release position where the lock pawl 331 is separated from the ratchet teeth 320; A cruise release urging member 340 that urges toward the position, the cruise operation member 310 and the cruise member 3 And a cruise link 350 that operates connecting 0.

The cruise operation mechanism 300 operates as follows.
When the HST 30 is shifted in the forward region (region in which the work vehicle travels forward) via the shift operation mechanism 200, the urging force of the cruise release urging member 340 is resisted via the cruise operation member 310. When the cruise member 330 is positioned at the cruise position, the lock claw 331 engages with the corresponding ratchet teeth 320, thereby fixing the position of the shift operation member 230 around the shift operation shaft 220, The working vehicle 1 is held in a cruise state (a constant speed traveling state).

  Note that even if the cruise operation member 310 is positioned at the cruise position against the urging force of the cruise release urging member 340 and then the artificial operation force to the cruise operation member 310 is released, the cruise member 330 is also released. Is held at the cruise position against the urging force of the cruise release urging member 340 for the following reason.

FIG. 5 shows an enlarged side view of the vicinity of the ratchet teeth.
As described above, the speed change operation member 230 provided with the plurality of ratchet teeth 320 is urged toward the neutral side by the operation side neutral return mechanism and / or the HST side neutral return mechanism.
Therefore, in a state where the speed change operating member 230 is rotated forward about the speed change operation shaft 220, the plurality of ratchet teeth 320 are biased toward the neutral side (in the direction of arrow N in FIG. 5).
Here, as shown in FIG. 5, the ratchet teeth 320 are firstly directed toward the neutral side with respect to the axis of the speed change operation shaft 220 with reference to the state in which the speed change operation member 230 is rotated forward. It has a first surface 321 and a second surface 322 facing the forward side.

The first surface 321 is formed with the lock claw 331 when the shift operating member 230 rotated forward is to return to the neutral side by the operation side neutral return mechanism and / or the HST side neutral return mechanism. Engage.
On the other hand, the second surface 322 is separated from the lock claw 331 toward the circumferential neutral side with respect to the speed change operation shaft 220 in a state where the first surface 321 is engaged with the lock claw 331. .
That is, there is a gap between the second surface 322 and the lock claw 331 in a state where the first surface 321 is engaged with the lock claw 331.

According to such a configuration, when shifting the HST 30 in the forward travel region via the shift operation mechanism 200, the urging force of the cruise release urging member 340 is resisted via the cruise operation member 310. When the cruise member 330 is positioned at the cruise position, the lock pawl 331 engages with the corresponding ratchet tooth 320.
In this state, when the manual operation on the speed change operation mechanism 200 is released, the speed change operation member 230 is attached to the neutral side around the speed change operation shaft 220 by the operation side neutral return mechanism and / or the HST side neutral return mechanism. As a result, the first surface 321 abuts against the lock claw 331 in a state where the first surface 321 is biased toward the neutral side around the speed change operation shaft 220.
Friction resistance against the movement of the cruise member 330 about the cruise shaft 335 toward the cruise release position by the urging force of the cruise release urging member 340 due to the contact between the first surface 321 and the lock claw 331. Occurs.
Therefore, even if the cruise operation member 310 is positioned at the cruise position against the urging force of the cruise release urging member 340 and then the artificial operation force to the cruise operation member 310 is released, the cruise member 330 Is held in the cruise position.

  On the other hand, when the cruise operation member 310 is operated in the release direction while the cruise member 330 is positioned at the cruise position, the cruise member 330 is rotated around the cruise shaft 335 toward the cruise release position, The engagement of the ratchet teeth 320 corresponding to the lock claws 331 with the first surface 321 is released. Accordingly, the cruise member 330 is positioned at the cruise release position by the urging force of the cruise release urging member 340.

In the present embodiment having such a configuration, the cruise state is also released by operating the shift operation member 210.
That is, the cruise member 330 is cruised against the urging force of the cruise release urging member 340 via the cruise operation member 310 in a state where the HST 30 is shifted in the forward movement region via the shift operation member 210. When the manual operation on the speed change operation member 210 is released after being positioned, the cruise member 330 is held at the cruise position by the frictional resistance between the first surface 321 and the lock pawl 331 as described above. The
At this time, between the second surface 322 and the lock claw 331, as described above, the gap that allows the shift operation member 230 to rotate forward around the shift operation shaft 220 exists. .

In other words, in a state where the cruise member 330 is held at the cruise position, the shift operation member 210 is operated forward by a distance corresponding to the gap between the second surface 332 and the lock claw 331. It is possible.
When the speed change operation member 210 is operated forward in the cruise state, the engagement between the first surface 321 and the lock claw 331 is released, and the cruise member 330 is attached to the cruise release urging member 340. It is returned to the cruise release position by the force.

Next, the brake operation mechanism 400 will be described.
As shown in FIGS. 2 and 3, the brake operation mechanism 400 includes a brake operation member 410 that can be manually operated, a brake operation shaft 420 that rotates around an axis line in response to the human operation on the brake operation member 410, and A brake operating member 430 supported on the brake operation shaft 420 so as not to rotate relative to the brake operating shaft 420, a brake link 440 for operatively connecting the brake operating member 430 and the brake actuator, and the brake operating member 430 operatively to a brake release position. And a brake release urging member 450 that urges toward the end.

  As shown in FIGS. 2 and 3, the brake operation shaft 420 is supported so as to be rotatable about its axis in a state along the vehicle width direction.

The brake operation member 410 is connected to the brake operation shaft 420 so as not to be relatively rotatable.
In the present embodiment, the brake operation member 410 is a brake pedal as shown in FIGS.
The base of the brake pedal is connected to the brake operation shaft 420 so as not to rotate relative to the brake operation shaft 420, and the free end has a presser that can be operated by the driver.

As shown in FIG. 4, the brake actuating member 430 has a radially inner region 431 supported by the brake operation shaft 420 so as not to rotate relative to the brake operation shaft 420, and a diameter extending radially outward from the radially inner region 431. And a direction outward region 432.
In the present embodiment, as shown in FIGS. 2 to 4, the brake actuating member 430 is a plate-like member.

  The brake link 440 has one end connected to the radially outer region 432 of the brake operating member 430 and the other end connected directly or indirectly to the brake actuator.

  The brake release urging member 450 has one end connected to a fixed member such as the vehicle frame 10 and the other end connected to the brake operation member so as to urge the brake operation member 430 toward the brake release position. 430 is connected to a radially outer region 432 of 430.

The brake operation mechanism 400 having such a configuration operates as follows.
In a state where no manual operation is performed on the brake operation member 410, the brake operation member 430 is positioned at the brake release position around the brake operation shaft 420 by the urging force of the brake release urging member 450, and the brake link 440. The brake actuator is deactivated via

On the other hand, when the brake operation member 410 is operated to the brake position against the urging force of the brake release urging member 450, the brake operation shaft 420 rotates in the brake operation direction on one side around the axis line. Accordingly, the brake operating member 430 is positioned at the brake operating position around the brake operation shaft 420.
By the rotation of the brake operation member 430, the brake actuator is activated through the brake link 440.

  In the present embodiment, the working vehicle 1 differentially transmits the output from the HST 30 to a pair of drive wheels (a pair of rear wheels in the present embodiment) on the side on which the traveling brake device acts. A differential gear mechanism (not shown), a differential lock mechanism (not shown) that locks differential transmission by the differential gear mechanism, and a differential lock operation mechanism 500 that artificially operates the differential lock mechanism (see FIGS. 2 and 3). The brake operation mechanism 400 allows the travel brake via the brake operation member 410 while allowing a single operation of the differential lock operation mechanism 500 regardless of whether or not the brake operation member 410 is operated. When shifting the device from the brake release state to the brake operation state, the differential lock operating mechanism 500 is interlocked. And a brake differential lock link structure to shift to a differential-lock state Te.

FIG. 6 shows a left side view of the traveling speed operation device 100 and the mission case 40. FIG. 7 is a perspective view of the brake / diff lock link structure.
As shown in FIGS. 6 and 7, the diff lock operating mechanism 500 includes a diff lock operating member 510 (a diff lock pedal in the present embodiment) supported rotatably around a diff lock operating shaft 515 along the vehicle width direction, A differential lock release biasing member 520 that biases the differential lock operation member 510 toward the differential lock release position, and a differential lock link 530 having one end connected to the differential lock operation member 510 and the other end operatively connected to the differential lock mechanism. The differential lock mechanism shifts from the differential lock release state to the differential lock state by operating the differential lock operation member 510 from the differential lock release position to the differential lock position against the biasing force of the differential lock release biasing member 520. Is configured to do.

As shown in FIGS. 4, 6 and 7, the brake / diff lock link structure has a long hole 560 formed in the brake operating member 430 and a first end portion of the brake operating through the long hole 560. A rigid link member 570 connected to the member 430 and having a second end connected to the differential lock operating member 510 is provided.
The elongated hole 560 includes a proximity end 561 (a rear end in the present embodiment) on the side close to the differential lock operation member 510, a separation end 562 on the side separated from the differential lock operation member 510, And an intermediate portion 563 that communicates between the proximity end portion 561 and the separation end portion 562.

  The link member 570 has the first end of the elongated hole 560 when the differential lock operating member 510 is positioned at the differential lock release position while the brake operation member 430 is positioned at the brake release position. When the differential lock operation member 510 is positioned at the differential lock position with the brake actuating member 430 positioned at the brake release position and positioned at the proximal end 561, the first end is the long end. The hole 560 is configured so as to be positioned at the separation end 562.

The brake / diff lock link structure operates as follows.
When the differential lock operation member 510 is operated from the differential lock release position to the differential lock position in a state where the brake operation member 410 is not operated (that is, the traveling brake device is in an inoperative state), the differential lock is set via the differential lock link 530. The mechanism shifts from the diff lock release state to the diff lock state.
At this time, the first end portion of the link member 570 moves from the proximity end portion 561 to the separation end portion 562 in the elongated hole 560, so that the differential lock operating member 510 is changed from the differential lock release position to the differential lock position. Depending on the operation, the brake actuating member 430 does not move. Accordingly, the diff lock mechanism shifts to the diff lock state while the traveling brake device is maintained in the brake non-operating state.

Next, the case where the brake operation member 410 is operated from the brake release position to the brake operation position in a state where the differential lock operation member 510 is not operated (that is, the differential lock release state of the differential lock mechanism) will be described.
In this case, in conjunction with the operation on the brake operation member 410, the brake operation member 430 is on one side around the brake operation shaft 420 (the long hole 460 is in a direction away from the differential lock operation member 510). 4, 6 and 7 rotate counterclockwise).

As described above, when both the brake operation mechanism 400 and the differential lock operation mechanism 500 are not operated, the first end portion of the link member 570 is positioned at the proximity end portion 561 of the elongated hole 560. Therefore, when the brake operation member 430 is rotated to one side around the brake operation shaft 420, the differential lock operation member 510 is rotated from the differential lock release position to the differential lock position via the link member 570.
Therefore, when the travel brake device is shifted from the brake release state to the brake operation state via the brake operation member 410, the diff lock mechanism is automatically in the diff lock release state without operating the diff lock operation mechanism 500. To the diff lock state.

  As shown in FIGS. 2, 4, 5, and 7, the traveling speed operation device 100 according to the present embodiment includes a brake that is supported on the brake operation shaft 420 so as not to rotate relative to the brake operation shaft 420. An interlocking arm 600 is provided, and the cruise state is released by an operation on the brake operation member 410 in addition to an operation on the cruise operation member 310 or the speed change operation member 210.

In FIG. 8, the cruise operation mechanism 300 is in a cruise state (a state in which the cruise operation member 310 is being operated to the cruise position), and the brake operation mechanism 400 is in a brake release state (to the brake operation member 410). The partial side view of the said traveling speed operating device 100 in the case of being made into the initial state where the human operation is not performed is shown.
FIG. 9 is a partial side view of the traveling speed operation device 100 when the cruise operation mechanism 300 is in a cruise state and the brake operation mechanism 400 is in the middle of transition from the brake release state to the brake operation state. Show.
Further, FIG. 10 shows a partial side view of the traveling speed operation device 100 when the brake operation mechanism 400 is in a brake operation state.

  As shown in FIGS. 8 to 10, the brake interlocking arm 600 moves the cruise member 330 positioned at the cruise position to the cruise shaft in response to the operation of the brake operation member 410 from the brake release position to the brake operation position. A cruise release arm portion 610 that is pushed around the 335 toward the cruise release position is provided.

In other words, the brake interlocking arm 600 is configured so that the brake operation shaft 420 and the brake operation direction on one side around the axis of the brake operation shaft 420 (in accordance with the operation from the brake release position to the brake operation position with respect to the brake operation member 410) It rotates in the counterclockwise direction in FIGS.
The cruise release arm portion 610 is separated from the cruise member 330 located at the cruise position when the brake linkage arm 600 is located at the brake release position (see FIG. 8). When it rotates from the brake release position to one side around the axis of the brake operation shaft 420, it engages with the cruise member 330 located at the cruise position (see FIG. 9).

When the brake interlocking arm 600 is further rotated from the position shown in FIG. 9 to one side around the axis of the brake operation shaft 420, the cruise release arm 610 moves the cruise member 330 around the cruise shaft 335. Push in the direction to cancel the cruise.
The cruising member 330 is disengaged from the ratchet teeth 320 by the pushing force of the cruising release arm portion 610, and is rotated to the cruising release position by the urging force of the cruise release urging member 340 (see FIG. 10). ).

  Furthermore, the traveling speed operation device 100 according to the present embodiment includes the operation-side neutral return mechanism that returns the speed change operation mechanism 200 to the neutral state when the manual operation on the speed change operation member 210 is released. Yes.

FIGS. 11 to 13 show side views corresponding to FIGS. 8 to 10 in a state in which the brake operation member 430 and the cruise member 330 are omitted, respectively.
As shown in FIGS. 8 to 13, the traveling speed operation device 100 includes a shift interlocking arm 700 supported in a swingable manner around a pivot shaft 705 parallel to the shift operation shaft 220 in addition to the above configuration. ing.

  As shown in FIGS. 11 to 13, the operation-side neutral return mechanism is configured so that the shift interlock cam portion 650 provided in the shift interlock arm 700 and the shift interlock cam portion 650 engage with the shift interlock cam portion 650. The shift interlock cam surface 660 provided on the operating member 230 and the shift interlock arm 700 are attached around the pivot shaft 705 in a direction in which the shift interlock cam portion 650 is engaged with the shift interlock cam surface 660. A shift interlocking arm biasing member 670 for biasing.

The shift interlocking cam portion 650 extends in a direction parallel to the pivot shaft 705 at a position spaced radially outward from the pivot shaft 705.
In the present embodiment, as shown in FIGS. 11 to 13, the shift interlocking cam portion 650 is a bearing member that is rotatably supported by a support shaft 706 provided in the shift interlocking arm 700. ing.

As shown in FIGS. 11 to 13, the speed change interlocking cam surface 660 has the deepest portion 661 located at the radially innermost end with respect to the axis of the speed change operation shaft 220 as a reference. It includes a pair of inclined portions 662F and 662F positioned radially outward with respect to the axis of the speed change operation shaft 220 as it goes to the one side and the other side in the circumferential direction with respect to the axis.
The pair of inclined portions 662F and 662F are forward-side inclined portions that respectively engage with the shift-linked interlocking cam portion 650 when the shift operation member 230 is rotated forward and backward about the shift operation shaft 220. A portion 662F and a reverse side inclined portion 662R are included.

The speed change operating member 230 has an outer peripheral surface that faces radially outward with respect to the axis of the speed change operation shaft 220.
In the present embodiment, the shift interlocking cam surface 660 is formed on the outer peripheral surface of the shift operation member 230 as shown in FIGS.
The plurality of ratchet teeth 320 are also formed on the outer peripheral surface.

  The shift interlocking arm biasing member 670 has one end at the shift interlocking arm 700 in order to bias the shift interlocking arm 700 in a direction in which the shift interlocking cam portion 650 engages with the shift interlocking cam surface 660. And the other end is directly or indirectly connected to a fixing member (not shown) such as the vehicle frame 10.

Such an operation side neutral return mechanism operates as follows.
As described above, when the speed change operation member 210 is operated forward, the speed change operation member 230 rotates about the speed change operation shaft 220 in the forward direction (counterclockwise in FIGS. 11 to 13). At this time, the shift operating member 230 resists the biasing force of the shift interlocking arm biasing member 670 by causing the forward cam surface 662F to push the shift interlocking cam portion 650. Then, it is rotated to the non-neutral position (see FIG. 11).

When the manual operation to the speed change operation member 210 is released from the state shown in FIG. 11, the speed change interlocking cam portion 650 pushes the forward cam surface 662F by the biasing force of the speed change interlocking arm biasing member 670 ( Finally, the shift operation member 230 is returned from the non-neutral position to the neutral position (see FIG. 13).
At this time, the shift interlocking cam portion 650 is held at a position corresponding to the deepest portion 661 by the shift interlocking cam surface 660, whereby both the shift operating member 230 and the shift interlocking arm 700 are in a neutral position. Retained.

FIG. 14 is a side view corresponding to FIG. 11 in a state in which the speed change operation member 210 is operated to the reverse side.
When the speed change operation member 210 is operated to the reverse side, the speed change operation member 230 rotates about the speed change operation shaft 220 in the reverse direction (clockwise direction in FIG. 14). At this time, the shift operating member 230 resists the biasing force of the shift interlocking arm biasing member 670 by causing the reverse cam surface 662R to push the shift interlocking cam portion 650. Then, it is rotated from the neutral position to the non-neutral position.
Even when the speed change operation member 210 is operated backward, the speed change interlocking arm 700 rotates about the pivot shaft 705 in the same direction as when the speed change operation member 210 is operated forward ( 11 and 14).

  When the manual operation to the shift operation member 210 is released from the state in which the shift operation member 210 is operated backward, the shift interlocking cam portion 650 is moved backward by the biasing force of the shift interlock arm biasing member 670. By pushing the side cam surface 662R, both the shift operating member 230 and the shift interlocking arm 700 are returned from the non-neutral position to the neutral position (see FIG. 13).

  The traveling speed operation device 100 according to the present embodiment further includes a brake-time HST neutral return mechanism that prevents the HST 30 from being in an output state when the traveling brake device is in an operating state.

  As shown in FIGS. 8 to 10, the brake HST neutral return mechanism includes a brake interlocking cam portion 750 provided in the shift interlocking arm 700 and a neutral groove 630 provided in the brake interlocking arm 600. I have.

The brake interlocking cam portion 750 extends in a direction parallel to the pivot shaft 705 at a position spaced radially outward from the pivot shaft 335.
In the present embodiment, as shown in FIGS. 8 to 14, the brake interlocking cam portion 750 is provided coaxially with the shift interlocking cam portion 650.
That is, in the present embodiment, the support shaft 706 that supports the bearing member that acts as the shift interlocking cam portion 650 acts as the brake cam portion 750.

  As shown in FIG. 10, when the brake interlocking arm 600 is positioned at the brake operating position in conjunction with the operation of the brake operating member 410 to the brake operating position, the brake HST neutral return mechanism A portion 750 is configured to be engaged with the neutral groove 630, and the brake interlocking cam portion 750 and the neutral groove 630 are configured such that the brake interlocking cam portion 750 is engaged with the neutral groove 630. In this state, the shift interlocking arm 700 is configured to be positioned at the neutral position.

Specifically, as shown in FIGS. 8 to 10, the neutral groove 630 includes a first end 631 on the side close to the pivot shaft 705, which is the rotation center of the shift interlock arm 700, and the pivot. A second end 632 on the side away from the shaft 705 and a first end 631 and an intermediate portion 633 communicating with the second end 632 are provided, and the first end 631 is an open end. It is said that.
That is, the neutral groove 630 extends substantially along the radial direction from the axis of the pivot shaft 705 that is the rotation center of the shift interlocking arm 700, and accordingly, the brake interlocking provided in the shift interlocking arm 700 is performed. When the cam portion 750 is engaged with the neutral groove 630, the shift interlock arm 700 is held so as not to rotate about the pivot shaft 705 in the neutral position.

Preferably, in the brake-time HST neutral return mechanism, the shift operation member 210 is in a non-neutral position (that is, the shift operation member 210 is operated in the forward side region or the reverse side region). When the brake interlocking arm 600 moves from the brake releasing position to the brake operating position around the brake operation shaft 420 in conjunction with the operation of the brake operating member 410 from the brake releasing position to the brake operating position, A guide surface 640 for guiding the cam portion 750 to the neutral groove 630 is provided.
In the present embodiment, the guide surface 640 is provided on the brake interlocking arm 600 as shown in FIGS.

Specifically, the guide surface 640 includes a radially inner end 641 and a radially outer end positioned radially inward and outward with respect to the axis of the brake operation shaft 420, and the radially inner end. 641 and an inclined surface 643 extending between the radially outer end portions 642.
The radially inner end portion 641 is connected to the open end portion of the neutral groove 630.
The inclined surface 643 allows the brake interlocking cam portion 750 to be moved from the radially outer end 642 side when the brake interlocking arm 600 rotates around the brake operation shaft 420 from the brake operating position to the brake releasing position. It is inclined so as to be guided toward the radially inner end portion 641.

The brake-time HST neutral return mechanism operates as follows.
In a traveling state in which the speed change operation member 210 is operated forward and the operation of the brake operation member 410 is not performed (see FIG. 8), the brake operation member 410 is directed from the brake release position toward the brake operation position. When the operation is started, the brake interlocking arm 600 rotates around the brake operation shaft 420 from the brake release position toward the brake operating position (counterclockwise in FIG. 8), and the guide surface 640 is interlocked with the brake interlocking shaft. The cam portion 750 is engaged (see FIG. 9).
When the brake operating member 410 is further operated toward the brake operating position from this state, the brake interlocking arm 600 is further rotated around the brake operating shaft 420 in the brake operating direction. By the rotation operation of the brake interlocking arm 600, the brake interlocking cam portion 750 is engaged with the neutral groove 630 while being guided by the guide surface 640, whereby the transmission interlocking arm 700 is in the neutral position. It is held unrotatable (see FIG. 10).

As described above, when the shift interlocking arm 700 is positioned at the neutral position, the shift operating member 230 is also held at the neutral position by the action of the shift interlocking cam portion 650 and the shift interlocking cam surface 660. (See FIG. 13).
Accordingly, the HST 30 operatively connected to the speed change operating member 230 is held in a neutral state.

Thus, in the traveling speed operation device 100 according to the present embodiment, when the traveling brake device is shifted to the brake operating state via the brake operation mechanism 400, the speed change operation mechanism 200 is neutral. Inoperable in the state.
Accordingly, it is possible to reliably prevent the traveling driving force from being output from the HST 30 when the traveling brake device is operated, thereby effectively preventing wear and damage to the traveling brake device and / or the HST 30. be able to.

Furthermore, in addition to the above configuration, travel speed operating device 100 according to the present embodiment includes neutral switch 800 that detects the neutral state of HST 30.
As shown in FIGS. 11 to 14, the neutral switch is configured to detect whether or not the shift interlocking arm 700 is positioned at the neutral position.
As described above, the rotation direction of the shift interlocking arm 700 around the pivot shaft 705 (see FIG. 11) when the shift operation member 230 rotates in the forward direction from the neutral position, and the shift operation member 230 The rotation direction (see FIG. 14) around the pivot shaft 705 of the speed change interlocking arm 700 when rotating in the reverse direction from the neutral position is the same.
Accordingly, by detecting the neutral position of the shift interlock arm 700 with the neutral switch 800 to detect the neutral state of the HST 30, it is possible to simplify the HST neutral detection structure.
In the present embodiment, a contact type switch is used as the neutral switch 800.

FIG. 1 is a left side view of a tractor to which a traveling speed operation device according to an embodiment of the present invention is applied. FIG. 2 is a perspective view of the traveling speed operation device as viewed from the front side and the left side. FIG. 3 is a perspective view of the traveling speed operation device as viewed from the front side and the right side. FIG. 4 is a partially enlarged perspective view of the traveling speed operation device. FIG. 5 is an enlarged side view of the vicinity of the ratchet teeth of the cruise operation mechanism in the travel speed operation device. FIG. 6 is a left side view of a transmission case in the traveling speed operation device and the working vehicle. FIG. 7 is a perspective view of a brake / diff lock link structure in the travel speed operation device. FIG. 8 is a partial side view of the travel speed operation device when the cruise operation mechanism is in a cruise state and the brake operation mechanism in the travel speed operation device is in a brake release state. FIG. 9 is a partial side view of the traveling speed operation device when the cruise operation mechanism is in a cruise state and the brake operation mechanism is in the middle of transition from the brake release state to the brake operation state. FIG. 10 is a partial side view of the traveling speed operation device when the brake operation mechanism is in a brake operation state. FIG. 11 is a side view corresponding to FIG. 8 in a state where the cruise member in the cruise operation mechanism and the brake operation member in the brake operation mechanism are deleted. FIG. 12 is a side view corresponding to FIG. 9 with the cruise member and the brake actuating member removed. FIG. 13 is a side view corresponding to FIG. 10 with the cruise member and the brake actuating member removed. FIG. 14 is a side view of the traveling speed operation device in a state where the cruise member and the brake actuating member are deleted, and shows a state where the shift operation mechanism is operated to the reverse side.

Explanation of symbols

30 HST
DESCRIPTION OF SYMBOLS 100 Travel speed operation apparatus 200 Transmission operation mechanism 210 Transmission operation member 220 Transmission operation shaft 230 Transmission operation member 240 HST operation link 300 Cruise operation mechanism 310 Cruise operation member 320 Ratchet tooth 330 Cruise member 340 Cruise release urging member 400 Brake operation mechanism 410 Brake operation member 420 Brake operation shaft 430 Brake operation member 440 Brake link 450 Brake release urging member 510 Differential lock operation member 560 Long hole 561 Proximity end 562 Separation end 563 Intermediate part 570 Link member 600 Brake interlocking arm 610 Cruise release arm 630 Neutral groove 640 Guide surface 650 Shifting interlocking convex portion 660 Shifting interlocking cam surface 670 Shifting interlocking arm urging member 700 Shifting interlocking arm 705 Pivot shaft 750 Brake interlocking protrusion 00 neutral switch

Claims (5)

A speed change operation mechanism for operating an output adjustment member of an HST, a speed change operation member that can be manually operated, a speed change operation shaft that rotates about an axis in response to the human operation to the speed change operation member, and the speed change operation A speed change operation mechanism having a speed change operation member supported so as not to rotate relative to the shaft, an HST operation link for operatively connecting the speed change operation member and the output adjustment member, and holding the speed change operation mechanism at a predetermined operation position. A cruise operation mechanism for switching a cruise state or a cruise release state in which the cruise state is released, the cruise operation member being manipulable, a plurality of ratchet teeth provided on the speed change operation member, and the cruise operation A cruise position that engages with the ratchet teeth around a cruise axis or a clutch that has been disengaged from the ratchet teeth according to an artificial operation on the member. A cruise operation mechanism having a cruise member capable of taking a cruise release position, a cruise release urging member that urges the cruise member toward the cruise release position, and a brake actuator of the traveling brake device. The brake operation mechanism is supported by a manually operable brake operation member, a brake operation shaft that rotates about an axis in response to an artificial operation to the brake operation member, and a non-rotatable relative to the brake operation shaft. A brake operation mechanism having a brake operation member, a brake link for operatively connecting the brake operation member and the brake actuator, and a brake release urging member that urges the brake operation member toward a brake release position. A travel speed operation device comprising:
A brake interlocking arm supported on the brake operation shaft so as not to rotate relative to the brake operation shaft, wherein the cruise member positioned at a cruise position is moved to the cruise shaft in response to an operation of the brake operation member from a brake release position to a brake operation position. A brake interlocking arm with a cruise release arm that pushes around the cruise release position,
A shift interlocking arm supported so as to be swingable around a pivot shaft parallel to the shift operation shaft, and including a shift interlocking arm provided with a shift interlocking cam part and a brake interlocking cam part,
The shift operation member is further separated from the shift operation shaft toward the one side and the other side in the circumferential direction with respect to the shift operation shaft with the deepest portion closest to the shift operation shaft interposed therebetween. A shift interlocking cam surface including a pair of inclined portions that engage with the shift interlocking cam portion when the operation member is located in a non-neutral position;
The shift interlock arm is biased about the pivot shaft by a shift interlock arm biasing member in a direction in which the shift interlock cam portion engages with the shift interlock cam surface,
The brake interlocking arm is further provided with a neutral groove for holding the shift interlocking arm in the neutral position by engaging the brake interlocking cam portion when the brake operating member is positioned at the brake operating position. A traveling speed operation device characterized by being provided.   The travel speed operation device according to claim 1, wherein the shift interlocking cam part and the brake interlocking cam part are arranged coaxially.   When the brake operating member is operated from the brake release position to the brake operating position in a state where the speed change operating member is located at the non-neutral position, the brake interlocking arm moves the brake interlocking cam portion to the neutral groove. The travel speed operation device according to claim 1, wherein a guide surface for guiding is provided. A neutral switch for detecting the neutral state of the HST,
The travel speed operation device according to any one of claims 1 to 3, wherein the neutral switch detects whether or not the shift interlocking arm is positioned at a neutral position. A first end connected to the brake operating member and a second end connected to a differential lock operating member that is rotatable about a differential lock operating shaft parallel to the brake operating shaft to operate the differential lock mechanism. A link member,
The brake actuating member includes a proximity end portion on a side close to the differential lock operation member, a separation end portion on a side separated from the differential lock operation member, and an intermediate communicating between the proximity end portion and the separation end portion. And a long hole having a portion,
The link member is configured such that when the differential lock operation member is positioned at the differential lock release position in a state where the brake operation member is positioned at the brake release position, the first end portion is at the proximity end portion of the elongated hole. When the differential lock operating member is positioned at the differential lock position with the brake actuating member positioned at the brake release position, the first end portion is positioned at the separation end portion of the elongated hole. The travel speed operation device according to any one of claims 1 to 4, wherein the travel speed operation device is configured as described above.

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