JP5634162B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle such as a crawler tractor.

  A pair of left and right crawler traveling devices, a pair of left and right hydraulic continuously variable transmissions (for example, HST) that are provided for each crawler traveling device and continuously change the power of each crawler traveling device, and a hydraulic continuously variable transmission A pair of left and right connecting link mechanisms that mechanically connect the shift operation arm and the travel operation tool of each hydraulic continuously variable transmission and rotate the shift operation arm in accordance with the operation of the travel operation tool. Work vehicles such as crawler tractors provided are known.

  A hydraulic continuously variable transmission such as an HST is configured to shift and output input power at a predetermined gear ratio by rotating a shift operation arm to a predetermined position. Even if it has a structure, there are some individual differences, and there is also an operating error in the left and right connecting link mechanisms, so even if the traveling operation tool is in a straight operation state, the left and right hydraulic continuously variable transmissions In some cases, the straightness of the work vehicle may deteriorate without synchronization.

  Therefore, at least one of the connecting rods provided in each connecting link mechanism is configured to be adjustable in length, and based on the adjustment of the length of the connecting rod, individual differences of the hydraulic continuously variable transmission and the connecting link mechanism It has been proposed to correct the speed difference between the left and right crawlers due to the dimensional error (see, for example, Patent Document 1). The same effect can be obtained even if at least one of the link arms provided in each connection link mechanism is configured to be adjustable in arm length.

JP-A-8-132906

  However, conventionally, when adjusting the length of the connecting rod and the arm length of the link arm, it is necessary to use a dedicated adjustment jig, and it is difficult to adjust without the adjustment jig. For example, in the case of readjustment on site after shipment, if there is no adjustment jig, the reference lengths of the connecting rod and link arm are unknown, so adjustment work is extremely difficult and accurate adjustment is difficult.

The present invention has been created in view of the above-described circumstances to solve these problems. The invention of claim 1 is provided for each pair of left and right crawler traveling devices and each crawler traveling device. , A pair of left and right hydraulic continuously variable transmissions for steplessly changing the power of each crawler traveling device, and a shift operation arm and a travel operation tool of each hydraulic continuously variable transmission provided for each hydraulic continuously variable transmission In a work vehicle comprising a pair of left and right connecting link mechanisms that rotate the shift operating arm in response to an operation of the travel operation tool, at least one of the link arms provided in each connecting link mechanism. When configuring the arm length to be adjustable, the link arm with adjustable arm length is an arm length adjustment that adjusts the arm length of the link arm based on a change in position relative to the arm body. Has a member, the said arm length adjusting member, the gauge having a contact surface which indicates a reference position of the arm length adjusting member by bringing into contact with the extension piece provided on the arm body side is provided, the By reversing the gauge, the arm length adjustment member can be selected to move between the direction in which the contact surface separates from the extension piece and the direction in which the contact surface is released from the extension piece and beyond the extension piece Thus, the work vehicle is configured so that the arm length can be adjusted between the direction of shortening and the direction of lengthening from the reference position .
According to a second aspect of the present invention, the hydraulic continuously variable transmission includes a pair of angle sensors that are provided for each shift operation arm of the hydraulic continuously variable transmission device and detect an operation angle of each shift operation arm, and at least one of the angle sensors is used as a link arm. In connecting, and assuming that the detected angle of the link arm is the operating angle of the speed change operation arm, the gauge is provided on the arm length adjusting member and is connected to the sensor arm of the angle sensor for adjusting the arm length. The work vehicle according to claim 1, wherein the rotation range of the sensor arm is automatically adjusted by moving integrally with the arm length adjusting member and changing a connection position with the sensor arm. It is.

According to the first aspect of the present invention, since the gauge indicating the reference position of the arm length adjusting member is provided, the arm length can be accurately adjusted even in a situation where there is no dedicated adjusting jig.
According to the second aspect of the present invention, when the arm length is adjusted, the rotation range of the sensor arm can be automatically adjusted. Therefore, compared with the case where the rotation range of the sensor arm is separately adjusted, The workability can be improved.

It is a side view of a crawler tractor. It is a top view of a control part. It is a perspective view which shows the operation system of the hydraulic continuously variable transmission which concerns on a reference example. It is a principal part perspective view of the connection link mechanism which concerns on a reference example. It is a principal part perspective view of the connection link mechanism which concerns on embodiment of this invention. It is a side view of the link arm which concerns on embodiment of this invention. It is a perspective view of the link arm which concerns on embodiment of this invention. It is a disassembled perspective view of the link arm which concerns on embodiment of this invention. It is a principal part side view of the connection link mechanism which concerns on embodiment of this invention. It is a side view which shows the assembled state of the tension spring which concerns on a prior art example. It is a perspective view which shows the assembled state of the tension spring which concerns on a prior art example. It is a disassembled perspective view which shows the assembled state of the tension spring which concerns on a prior art example. It is a perspective view which shows the assembled state of the tension spring which concerns on this embodiment. It is a disassembled perspective view which shows the assembled state of the tension spring which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a reference example having a basic configuration in common with the embodiment of the present invention will be described with reference to FIGS. 1 to 4, and then the embodiment of the present invention will be described with reference to FIG. .

[Reference example]
In the drawings, reference numeral 1 denotes a traveling machine body of a crawler tractor. The traveling machine body 1 includes an engine (not shown) mounted on a front portion of the machine body, a pair of left and right crawler traveling devices 2, and left and right crawler traveling devices 2. A pair of hydraulic continuously variable transmissions 3A and 3B for independently shifting the traveling power supplied to the vehicle, a control unit 5 covered with a cabin 4, and a work machine connection unit 6 to which a work machine (not shown) is connected. Configured.

  As the hydraulic continuously variable transmissions 3A and 3B, HST is usually used. The HST is a combination of HST pumps (variable displacement hydraulic pumps) 7A and 7B driven by engine power and an HST motor (fixed displacement hydraulic motor) (not shown) driven by the discharge oil of the HST pumps 7A and 7B. The driving power is continuously variable.

  The HST pumps 7A and 7B used in the present embodiment are swash plate type variable displacement hydraulic pumps capable of adjusting the discharge oil amount steplessly based on the angle control of the swash plate, and on the side surfaces of the HST pumps 7A and 7B, Shift operation arms 8A and 8B are provided for performing respective swash plate operations. When both the shifting operation arms 8A and 8B are operated in the same direction, the left and right crawler traveling devices 2 are synchronously increased and decreased (including reverse rotation), and the traveling speed of the traveling machine body 1 changes. When one of the shift operation arms 8A and 8B is operated in the deceleration direction, the one crawler traveling device 2 is decelerated (including reverse rotation), and the traveling machine body 1 turns.

  As shown in FIG. 2, the control unit 5 is provided with a driver seat 9 on which an operator is seated and a travel operation tool operated by the operator. The travel operation tool includes a steering handle 10 provided in front of the driver's seat 9 and a travel shift lever 11 provided on the side of the driver's seat 9. The steering handle 10 and the travel speed change lever 11 are mechanically connected to the left and right speed change operation arms 8A and 8B via the HST link box 12 and the connecting link mechanisms 13A and 13B.

  The HST link box 12 is configured to rotate the left and right speed change operation arms 8A and 8B in a predetermined pattern in accordance with the operation of the steering handle 10 and the travel speed change lever 11. For example, when the travel shift lever 11 is operated from the neutral position to the forward travel side, the left and right shift operation arms 8A and 8B are rotated to the forward travel side, while the travel shift lever 11 is operated from the neutral position to the reverse travel side. If it is, the left and right speed change operation arms 8A and 8B are rotated to the reverse travel side.

  Further, when the traveling speed change lever 11 is operated to a position other than the neutral position and the steering handle 10 is operated to the neutral position (straight forward position), the left and right crawler traveling devices 2 are driven at the same speed. In this manner, the left and right speed change operation arms 8A and 8B are rotated synchronously. Further, when the traveling speed change lever 11 is operated to a position other than the neutral position and the steering handle 10 is operated to any one of the left and right turning positions, the crawler traveling device 2 inside the turning is the crawler traveling device outside the turning. The left and right speed change operation arms 8A and 8B are relatively rotated so as to be driven at a lower speed (including reverse rotation) than 2.

  The connection link mechanisms 13A and 13B are provided for each of the hydraulic continuously variable transmissions 3A and 3B, and mechanically connect the shift operation arms 8A and 8B of the hydraulic continuously variable transmissions 3A and 3B to the HST link box 12. . When the steering handle 10 or the travel shift lever 11 is operated, the HST link box 12 rotates the shift operation arms 8A and 8B via the connection link mechanisms 13A and 13B.

  3 and 4 includes link arms 14A and 14B that rotate back and forth with an intermediate portion as a fulcrum, and a connecting rod that connects one end of the link arms 14A and 14B to the HST link box 12. 15A, 15B, and connecting rods 16A, 16B for connecting the other ends of the link arms 14A, 14B to the speed change operation arms 8A, 8B.

  At least one of the link arms 14A and 14B provided in each of the connecting link mechanisms 13A and 13B can be adjusted with a substantial arm length L1. The arm length adjustment member 17 that adjusts the arm length L1 of the link arm 14B based on the position change with respect to the arm body is provided in the link arm 14B that can adjust the arm length.

  Specifically, the arm length adjusting member 17 shown in FIG. 4 integrally has a connecting pin 17a connected to the connecting rod 16B, and the position of the connecting pin 17a is set to the long hole 14a of the link arm 14B. By moving it along, the arm length L1 of the link arm 14B is changed. The arm length adjusting member 17 at the time of non-adjustment is fixed to the protruding piece 14b of the link arm 14B through a fixing bolt 18 so as not to move. When adjusting the arm length L1, the arm length adjusting member 17 is moved in the length direction of the link arm 14B by turning the pair of nuts 19 that fix the fixing bolt 18 to the projecting piece 14b. It becomes possible to move to.

  As shown in FIG. 4, a pair of angle sensors (potentiometers) 20 </ b> A and 20 </ b> B for detecting the operation angles of the respective shift operation arms 8 </ b> A and 8 </ b> B are connected to the connection link mechanisms 13 </ b> A and 13 </ b> B. And in this reference example, based on the operation angle of each speed change operation arm 8A, 8B which these angle sensors 20 detect, the drive speed calculation of the left and right crawler traveling device 2, and the vehicle speed calculation of traveling body 1 are performed, It is used for vehicle speed display.

  As shown in FIG. 4, in the present reference example, when providing a pair of angle sensors 20A and 20B for detecting the operation angles of the respective shift operation arms 8A and 8B, one angle sensor 20B is connected to the link arm 14B, The detection angle of the link arm 14B is regarded as the operation angle of the speed change operation arm 8B. That is, the sensor arm 20a of the angle sensor 20A is connected to the sensor pin 21 protruding from the speed change operation arm 8A, while the sensor arm 20a of the angle sensor 20B is connected to the sensor pin 22 protruding from the link arm 14B. . In this case, even when the pair of shift operation arms 8A and 8B are arranged apart from each other, the pair of angle sensors 20A and 20B can be arranged close to each other, thereby improving maintenance performance and the like. Become.

  The reference example configured as described above has two problems. The first problem is that when adjusting the arm length of the link arm 14B, it is necessary to use a dedicated adjustment jig, and it is difficult to adjust in a situation where there is no adjustment jig. For example, in the case of readjustment on site after shipment, if there is no adjustment jig, the reference length of the link arm 14B is unknown, so adjustment work is extremely difficult, and accurate adjustment is difficult.

  The second problem is that an error occurs in the detection value of the angle sensor 20B according to the arm length adjustment of the link arm 14B. That is, when the arm length L1 of the link arm 14B is adjusted, the rotation range of the speed change operation arm 8B is changed, and accordingly, the rotation range of the angle sensor 20B needs to be changed. Since 20B considers the angle of the link arm 14B as the operation angle of the speed change operation arm 8B, even if the arm length is adjusted, the rotation range of the sensor arm 20a does not change, which causes an error.

  Hereinafter, a crawler tractor according to an embodiment of the present invention capable of solving these problems will be described with reference to FIG. However, about the same structure as a reference example, description of a reference example is used by using the same code | symbol as a reference example.

Embodiment of the present invention
As shown in FIGS. 5 to 9, in the embodiment of the present invention, when configuring at least one of the link arms 14 </ b> A and 14 </ b> B provided in the connection link mechanisms 13 </ b> A and 13 </ b> B so that the arm length can be adjusted, The arm length adjusting member 17 that adjusts the arm length L1 of the link arm 14B based on the position change with respect to the arm body is provided on the link arm 14B that can be adjusted in height, similar to the above reference example. The point which provided the gauge 23 which shows the reference position of the arm length adjustment member 17 in the arm length adjustment member 17 is different from the said reference example. By doing so, the reference position of the arm length adjusting member 17 becomes clear even when there is no dedicated adjustment jig, and the arm length L1 of the link arm 14B can be accurately adjusted .

  Specifically, the gauge 23 of the present embodiment is a plate member that is attached to the arm length adjusting member 17 via a bolt 24 (concentric with the connecting pin 17a), and is formed at the lower left end of the plate member. When the abutment surface 23a abuts on the extension piece 14c formed to extend to the left side of the projecting piece 14b (extension dimension L2) from above, the arm length adjusting member 17 is connected to indicate the reference position. A distance L3 between the center of the pin 17a and the contact surface 23a is set. A flank 23b is formed at the lower right side of the gauge 23 so as to escape above the abutment surface 23a.

  When adjusting the arm length L1 of the link arm 14B having such a gauge 23, first, the arm length adjusting member 17 is moved to change the contact surface 23a of the gauge 23 to the extension piece 14c of the protruding piece 14b. Abutting from above, the reference position of the arm length adjusting member 17 is confirmed. When the gauge 23 interferes with the turning operation of the nut 19 when the arm length adjusting member 17 is moved, the nut 19 can be exposed by loosening the bolt 24 and rotating the gauge 23. .

Here, when adjusting the arm length L1 of the link arm 14B to the short side, the nut 19 is turned to move the arm length adjusting member 17 to the arm fulcrum side, that is, the arm length adjusting member 17 abuts. The arm length L1 is adjusted to the short side by moving (upwardly moving) the surface 23a away from the extension piece 14c . On the other hand, when the arm length L1 of the link arm 14B is adjusted to the long side, the movement of the arm length adjusting member 17 is restricted by the contact between the gauge 23 and the projecting piece 14b. 23 is once removed and the front and back of the gauge 23 are reversed. When you select the back side is turned upside down, the abutment surface 23a of the gauge 23 is right flank 23b is a left movement since regulation is released by the contact between the extension piece 14c, the abutment surface 23a can move in the direction beyond the extension piece 14c (downward movement), and the arm length adjusting member 17 can be moved in the direction of increasing the arm length L1. Thereafter, the arm length L1 is adjusted to the longer side by turning the nut 19 to move the arm length adjusting member 17 away from the arm fulcrum.

  In the embodiment of the present invention, a pair of angle sensors 20A and 20B are provided for each of the shift operation arms 8A and 8B of the hydraulic continuously variable transmissions 3A and 3B and detect the operation angle of each of the shift operation arms 8A and 8B. And at least one of the angle sensors 20B is connected to the link arm 14B and the detected angle of the link arm 14B is regarded as the operation angle of the speed change operation arm 8B. The length adjusting member 17 is provided with a gauge 23, and the gauge 23 is connected to the sensor arm 20a of the angle sensor 20B. When adjusting the arm length, the arm length adjusting member 17 and the gauge 23 are moved together, In contrast to the above reference example, the rotation range of the sensor arm 20a is automatically adjusted by changing the connecting position of the gauge 23 and the sensor arm 20a. It is. In this way, when the arm length is adjusted, the rotation range of the sensor arm 20a can be automatically adjusted, so that the workability at the time of adjustment can be improved as compared with the case where the rotation range of the sensor arm 20a is separately adjusted. Can be improved.

  More specifically, the sensor pin 23c is integrally provided on the gauge 23, and the link arm is formed by engaging the sensor pin 23c with a long hole 20b formed in the sensor arm 20a of the angle sensor 20B. The angle change of 14B is transmitted to the sensor arm 20a and is detected by the angle sensor 20B. The rotation center of the sensor arm 20a is offset by a predetermined dimension L4 upward with respect to the rotation center of the link arm 14B. As a result, when the arm length of the link arm 14B is adjusted, the rotation range of the sensor arm 20a can be automatically adjusted. Incidentally, when the rotation center of the sensor arm 20a and the link arm 14B is concentric, even if the arm length adjusting member 17 is moved in the arm length direction, the rotation range of the sensor arm 20a does not change.

  The automatic adjustment operation will be described with reference to FIG. The upper side of FIG. 9 shows the main part of the connecting link mechanism 13A, and the lower side of FIG. 9 shows the main part of the connecting link mechanism 13B including the link arm 14B whose arm length can be adjusted. Here, in the connecting link mechanism 13A shown in the upper side of FIG. 9, when the travel shift lever 11 is operated and the link arm 14A rotates 30 °, the shift operation arm 8A also rotates 30 °. The sensor arm 20a of the sensor 20 rotates 25.3 °.

  On the other hand, in the connecting link mechanism 13B shown in the lower side of FIG. 9, if the travel shift lever 11 is operated and the link arm 14B rotates 30 ° like the link arm 14A, it is not necessary to adjust the arm length. If the link backlash exists and the link arm 14B rotates only 28 °, the speed change operation arm 8B also rotates only 28 °. Therefore, even if the steering handle 10 is neutral, the crawler is caused by the difference in rotation between the left and right. The tractor turns left or right.

  Therefore, the arm length L1 of the link arm 14B is adjusted so that when the link arm 14B rotates 28 °, the speed change operation arm 8B rotates 30 °. Specifically, the arm length adjusting member 17 is lowered by 6.95 mm downward. In that case, in the sensor arm 20a of the angle sensor 20B, the rotation range is automatically adjusted from 23.70 ° before adjustment to 25.1 °, and approximated to 25.3 °, which is the rotation range of the angle sensor 20A. The

  Next, a crawler traveling device 2 according to a conventional example and this embodiment will be described with reference to FIGS. 1 and 10 to 14. As shown in FIG. 1, the crawler traveling device 2 includes a square pipe-shaped crawler frame 30, drive sprockets 31 and idler wheels 32 provided before and after the crawler frame 30, and a plurality of rollers provided below the crawler frame 30. A ring 33 and a crawler 34 suspended by these ring bodies 31, 32, 33 are provided.

  As shown in FIG. 10, the crawler frame 30 has an adjuster arm 35 that supports the idler wheel 32 movably back and forth, a tension spring 36 that applies a predetermined tension load to the idler wheel 32 via the adjuster arm 35, and An adjuster cylinder 37 that adjusts the longitudinal position of the idler wheel 32 via the tension spring 36 and the adjuster arm 35 is provided. A grease supply valve 30a is provided on the front end side of the crawler frame 30, and by supplying grease from here, the cylinder 37a of the adjuster cylinder 37 is extended, and the idler wheel 32 is moved or pressed backward. ing.

  As shown in FIGS. 11 and 12, in the conventional crawler traveling device 2, a spring assembly A including a tension spring 36, a spring guide 38, a support 39, a nut 40, and the like is configured in advance, and the spring assembly A is configured as a crawler frame 30. It is built in. In this case, although there is an advantage that the spring load of the tension spring 36 can be set before assembling, there is a problem that the number of parts and the number of assembly processes increase.

  Therefore, in the present embodiment, as shown in FIGS. 13 and 14, the tension spring 36 can be directly incorporated into the crawler frame 30 without configuring the spring assembly A in advance. Specifically, the tension spring 36 is directly assembled into the crawler frame 30 together with a pair of front and rear spring guides 41 that fit and hold the front end portion and the rear end portion of the tension spring 36, and then the crawler 34 is adjusted by the adjuster cylinder 37. The spring load of the tension spring 36 is set when the tension is applied. Further, in such a spring assembling method, the tension spring 36 is incorporated with a free length, so that the adjuster arm 35 is shortened by a difference (L11−L12) between the free length of the tension spring 36 and the set length, By extending the extension stroke of the adjuster cylinder 36 by the difference, the total length when the crawler is mounted is made the same.

  According to the present embodiment configured as described, a pair of left and right crawler travel devices 2 and a pair of left and right hydraulic non-speed gears provided for each crawler travel device 2 and continuously changing the power of each crawler travel device 2. Provided for each of the stepless transmissions 3A and 3B and the hydraulic continuously variable transmissions 3A and 3B, mechanically connecting the shift operation arms 8A and 8B of the hydraulic continuously variable transmissions 3A and 3B and the travel operation tool, In a crawler tractor including a pair of left and right connection link mechanisms 13A and 13B that rotate the speed change operation arms 8A and 8B according to the operation of the travel operation tool, the link arms 14A and 14B provided in the connection link mechanisms 13A and 13B In configuring at least one of the arm lengths so that the arm length can be adjusted, the link arm 14B capable of adjusting the arm length can be changed based on the position change relative to the arm body. Since the arm length adjusting member 17 for adjusting the arm length L1 of the arm 14B is provided and the gauge 23 indicating the reference position of the arm length adjusting member 17 is provided on the arm length adjusting member 17, a dedicated adjustment is performed. Even when there is no jig, the arm length L1 can be accurately adjusted.

  In addition, a pair of angle sensors 20A and 20B are provided for each of the shift operation arms 8A and 8B of the hydraulic continuously variable transmission devices 3A and 3B, and detect the operation angle of each of the shift operation arms 8A and 8B. In connecting the angle sensor 20B to the link arm 14B and considering the detected angle of the link arm 14B as the operation angle of the speed change operation arm 8B, the gauge 23 is provided on the arm length adjusting member 17 and the angle sensor 20B. When the arm length is adjusted, the rotation range of the sensor arm 20a is automatically adjusted by moving integrally with the arm length adjusting member 17 and changing the connection position with the sensor arm 20a. Therefore, the workability at the time of adjustment can be improved as compared with the case where the rotation range of the sensor arm 20a is separately adjusted. Kill.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 2 Crawler traveling apparatus 3 Hydraulic continuously variable transmission 8 Shift operating arm 10 Steering handle 11 Traveling shift lever 12 Link box 13 Linking link mechanism 14 Link arm 17 Arm length adjustment member 20 Angle sensor 20a Sensor arm 23 Gauge

Claims (2)

A pair of left and right crawler travel devices;
A pair of left and right hydraulic continuously variable transmissions that are provided for each crawler traveling device and that continuously change the power of each crawler traveling device;
A pair of left and right gears that are provided for each hydraulic continuously variable transmission, mechanically connect the shift operation arm of each hydraulic continuously variable transmission and the travel operation tool, and rotate the shift operation arm according to the operation of the travel operation tool. In a work vehicle provided with a connecting link mechanism of
In configuring at least one of the link arms provided in each link mechanism so that the arm length can be adjusted,
The link length adjustable arm has an arm length adjusting member that adjusts the arm length of the link arm based on a position change with respect to the arm body,
The arm length adjustment member is provided with a gauge having a contact surface indicating a reference position of the arm length adjustment member by contacting an extension piece provided on the arm body side ,
By reversing the gauge, the arm length adjusting member can be selected to move in the direction in which the contact surface is separated from the extension piece and in the direction in which the contact surface is released from the extension piece and beyond the extension piece. Thus, the work vehicle is configured to be able to adjust the direction in which the arm length is shortened and lengthened from the reference position . Provided for each speed change operation arm of the hydraulic continuously variable transmission, provided with a pair of angle sensors for detecting the operation angle of each speed change operation arm, and connecting at least one angle sensor to the link arm, In considering the detected angle as the operating angle of the shift operation arm,
The gauge is provided on the arm length adjusting member and connected to the sensor arm of the angle sensor. When adjusting the arm length, the gauge moves integrally with the arm length adjusting member to change the connecting position with the sensor arm. The work vehicle according to claim 1, wherein the rotation range of the sensor arm is automatically adjusted.

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