JP5457309B2 - Crawler traveling device for rear wheel in traveling vehicle - Google Patents

Description

  The present invention relates to a crawler traveling device used for left and right rear wheels of a traveling vehicle such as a tractor.

  Application of the crawler traveling device to the left and right rear wheels of a traveling vehicle such as a tractor, that is, configuring the rear wheels of the traveling vehicle as a crawler traveling device is described in Patent Documents 1 to 3 as prior art. Has been.

  As shown in FIG. 8, the crawler traveling device for a rear wheel (half crawler traveling device) in the prior art attaches the driving wheel body 4 to the rear axle 3 that is pivotally supported by the rear axle case 2 in the traveling machine body 1. A track frame 5 configured to extend in the front-rear direction is disposed at a position below the rear axle case 2, and a substantially middle portion in the front-rear direction of the track frame 5 is disposed on the side of the traveling vehicle body 1 such as the rear axle case 2. In addition, the track frame 5 is pivotably mounted on a swing fulcrum shaft 6 disposed at a position below the rear axle 3 by an appropriate distance R, and the front and rear portions of the track frame 5 are vertically moved in opposite directions. The front driven wheel body 7 provided at the front end of the track frame 5, the rear driven wheel body 8 provided at the rear end, and the drive wheel body 4 are endless in a substantially triangular shape. Wrap the strip 9 The strip 9, by rotating in the drive wheel body 4, and a configuration of performing forward driving or reverse travel of the traveling machine body 1.

Japanese Patent Laid-Open No. 08-045051 JP 2004-017788 A JP 2004-017789 A

  The prior art has a configuration in which a swing fulcrum shaft 6 that is a pivot point of the track frame 5 on the traveling machine body side in the crawler traveling device is located in a portion of the traveling machine body below the rear axle 2. Thus, as shown in FIG. 8, the track frame 5 is rotated clockwise around the swing fulcrum shaft 6 by the forward reaction force Pf from the ground and tilts forwardly as shown in FIG. Therefore, a predetermined traction force can be obtained during forward travel.

  In addition, as shown in FIG. 8, the track frame 5 is rotated counterclockwise around the swing fulcrum shaft 6 by the backward reaction force Pb from the ground and tilted rearward when traveling backward. Therefore, a predetermined traction force can be obtained with certainty during reverse travel.

  However, on the other hand, when the traveling machine body 1 is pitched so that the front part thereof moves up and down, the traveling machine body 1 is pivotally attached to the track frame 5 that contacts the ground via the endless belt 9. There is a problem as described below because it is tilted forwardly or tilted forwardly and downwardly about the pivot fulcrum shaft 6 that is a point.

  That is, the rear axle case 2 and the rear axle 3 in the traveling machine body 1 are arranged so that the traveling machine body 1 has an appropriate unit angle θ1 (for example, θ1 = 15 in the drawing of FIG. When the tilting pivot is moved upward by a predetermined degree, the swinging fulcrum shaft 6 moves to the track frame 5 in the rearward direction by a distance L1, while the swinging fulcrum shaft 6 is moved appropriately. When tilted and rotated forward and downward by a unit angle θ2 (for example, θ2 = 15 degrees on the drawing of FIG. 8), a distance of L2 in the forward direction with respect to the swing fulcrum shaft 6 and consequently the track frame 5 Just move.

  The distance L1 in the rearward direction and the distance L2 in the forward direction relative to the track frame 5 during the pitching are the distance R in the height direction from the swing fulcrum shaft 6 to the rear axle 3. In other words, when the traveling machine body 1 is pitched, the distance to move back and forth with respect to the grounded track frame is the swing fulcrum shaft of the track frame 5 with respect to the traveling machine body 1. Since 6 is located in the lower part of the rear axle 3 in the traveling body 1, the distance R in the height direction is increased by a large amount, so that the ride comfort is remarkably deteriorated.

  In addition, the support of the track frame 5 to the traveling machine body 1 is only one-point support by the swing fulcrum shaft 6, and the load is concentrated on the portion of the swing fulcrum shaft 6. In addition to hindering the enlargement of the wheel crawler travel device, there is also a problem that there is a large risk of malfunction due to torsional deformation or the like in the portion of the swing fulcrum shaft 6.

  This invention makes it the technical subject to provide the crawler traveling device for rear wheels (half crawler traveling device) which eliminated these problems.

In order to achieve this technical problem, claim 1
"A traveling body supported by the front wheels, a driving wheel mounted on the rear axle of the rear axle case at the rear of the traveling body, a track frame disposed below the driving wheel, and a front and rear mounting on the track frame. A crawler traveling device for a rear wheel comprising a front driven wheel body and a rear driven wheel body, wherein an endless belt-like body is wound around the drive wheel body, the front driven wheel body and the rear driven wheel body,
The track frame can be moved forward and backward by a front link member disposed on the front side of the rear axle and a rear link member disposed on the rear side of the rear axle on a traveling body including the rear axle case. is connected to the front link member, while its lower end pivot axis is inclined to the front side obliquely downward direction so as to be located forward of the upper pivot axis, the rear link member, the lower end pivot axis is inclined to the rear how obliquely downward direction so as to be positioned on the rear side of the upper pivot axis. "
It is characterized by that.

Claim 2
“In the description of claim 1, the lower pivot shaft of the rear link member is constituted by a support shaft for the track frame of the rear driven wheel.”
It is characterized by that.

Furthermore, claim 3
“In the first or second aspect of the invention, between the traveling body and the track frame, there is provided a restricting means for restricting the forward and backward movement of the track frame to a predetermined distance.”
It is characterized by that.

In addition, claim 4
“In any one of claims 1 to 3, one or both of an upper end pivot shaft of the front link member and an upper pivot shaft of the rear link member are connected to the rear axle. It is composed of torsion shafts arranged so as to extend in parallel. "
It is characterized by that.

  The track frame connected to the traveling machine body by a pair of front and rear link members moves forward with respect to the traveling machine body due to a forward reaction force received from the ground during forward traveling, and moves backward. When the vehicle travels, it moves backward with respect to the vehicle due to the reverse reaction force received from the ground.

  When the track frame moves in the forward direction with respect to the traveling machine body, the front link member of the pair of front and rear link members has an inclination angle with respect to a horizontal plane that is small with respect to the upper pivot shaft as a fulcrum (center). On the other hand, the track frame is tilted forwardly by rotating the rear link member so that the tilt angle from the horizontal plane is increased with the upper pivot shaft as the fulcrum (center).

  Further, when the track frame moves in the rearward direction with respect to the traveling machine body, the front link member of the pair of front and rear link members has an inclination angle from a horizontal plane with the upper pivot shaft as a fulcrum (center). The rear link member is rotated so that the inclination angle with respect to the horizontal plane becomes small with the upper pivot shaft as the fulcrum (center), so that the track frame is inclined rearwardly upward.

  As a result, the track frame is inclined forward and backward with respect to the traveling vehicle body, while being inclined forward and backward with respect to the traveling vehicle body. Since the load can be distributed to two locations by being supported by the pair of link members, it is possible to increase the size of the rear wheel crawler travel device and to cause malfunction due to torsional deformation or the like in the support. The fear can be reliably reduced.

  When the traveling aircraft body is pitched so that the front portion thereof is lowered during pitching of the traveling aircraft body, the front link member of the pair of front and rear link members is connected to the track frame that is grounded to the ground. The rear link member rotates with respect to the track frame with respect to the track frame, while the rear link member rotates relative to the track frame with the lower end pivoting shaft of the front link member as a fulcrum (center). It rotates so that the inclination angle from the horizontal plane becomes large with the landing axis as a fulcrum (center).

  Further, when the traveling body is pitched so that the front part thereof is raised, the front link member of the pair of front and rear link members is a lower end of the front link member with respect to the track frame that is in contact with the ground. The rear link member rotates with the pivot axis as a fulcrum (center) so that the inclination angle from the horizontal plane becomes larger, while the lower link axis of the rear link member is fulcrum (center) with respect to the track frame. As the angle of rotation from the horizontal plane becomes smaller.

  By the way, the track frame moves in the front-rear direction among the link mechanism constituted by the portion between the upper end pivot shafts of both link members of the traveling machine body, the pair of front and rear link members, and the track frame. The “instantaneous center” at the time is located at the intersection where the extension lines of the two link members intersect with each other, so that the track frame moves to rotate in the front-rear direction around the “instantaneous center”. .

In this case, the front and rear pair of link members, the link member, the lower end pivot axis is inclined laterally before so as to be positioned on the front side obliquely downward direction from the upper end pivot axis, the rear link member, the lower end by being arranged in V-shape so that pivot axis is inclined rearwardly how obliquely downward direction so as to be located rearward of the upper pivot axis, intersecting the extension line in these two link members are mutually The “instantaneous center”, which is the intersection, can be held at a position that approximates the height of the rear axle.

  As a result, when the traveling vehicle body pitches, the distance that the traveling vehicle body moves back and forth with respect to the track frame that touches the ground is centered on the swing fulcrum shaft that is located below the rear axle as in the prior art. Because it is much smaller than the case where it rotates, the ride comfort is improved and workability can be improved.

  According to the second aspect of the present invention, since the lower pivot shaft of the rear link member among the two link members can be used as the support shaft of the rear driven wheel body, the structure can be simplified and reduced in weight.

  Furthermore, according to the third aspect, the relative movement distance between the traveling machine body and the track frame can be restricted to a predetermined distance, so that safety can be ensured.

  In particular, according to the fourth aspect, the track frame can be supported by the independent suspension by the torsion shaft having a simple configuration with respect to the traveling machine body.

1 is a side view of a tractor according to an embodiment of the present invention. It is a bottom view of FIG. It is an enlarged view of the crawler traveling device for rear wheels among FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a sectional view taken along line VV in FIG. 3. It is a figure which shows the state when a traveling body is pitching forward and down. It is a figure which shows the state when a traveling body is pitching forward. It is a figure which shows the crawler traveling apparatus for conventional rear wheels.

  The drawings (FIGS. 1 to 7) when the embodiment of the present invention is applied to a track will be described below.

  In these drawings, reference numeral 10 denotes a tractor. The tractor 10 supports a traveling machine body 11, a pair of left and right front wheels 12 that support the front part of the traveling machine body 11, and the rear part of the traveling machine body 11. And a pair of left and right rear wheel crawler travel devices 13. The travel machine body 11 is equipped with an engine and a control seat.

  The crawler traveling device 13 is detachably attached to a rear axle case 14 at the rear portion of the traveling machine body 11 and a rear axle 15 pivotally supported on the rear axle case 14, and is attached to the rear axle 15. While the drive wheel body 16 is attached, a track frame 17 configured to extend in the front-rear direction is disposed at a position below the rear axle case 14, and the track frame 17 is integrated with the rear axle case 14. The mounting flange portion 18 provided on the front and rear can be moved back and forth by a front link member 19 disposed on the front side of the rear axle 15 and a rear link member 20 disposed on the rear side of the rear axle 15. It is linked to.

  A front driven wheel body 21 is attached to the track frame 17 at its front end via a tension adjusting mechanism 22, and a rear driven wheel body 23 is attached to its rear end by a support shaft 24. 16, the front driven wheel body 21, and the rear driven wheel body 23 are wrapped around an endless belt 25 such as a crawler or a caterpillar over a substantially triangular shape. The traveling vehicle body 11 is configured to perform forward travel or reverse travel by rotating forward or reverse at an appropriate speed on the driving wheel body 16 and thus the rear axle 15.

  In the track frame 17, a plurality of rolling wheels 26 contacting the portion between the front driven wheel body 21 and the rear driven wheel body 23 on the inner peripheral surface of the endless belt 25 are rotatable. Is provided.

  Under the rear axle case 14, a pair of front and rear torsion shafts 27 and 28 that constitute upper pivot shafts of a front link member 19 and a rear link member 20 described later extend in parallel with the rear axle 15. As shown in FIG. 4, one end thereof is fixed to the boss 29 on the side of the traveling machine body 11 so as not to be rotatable, and the other end is integrally provided with the rear axle case 14. The shaft 18 is rotatably supported by the portion 18 or the like.

  The upper end of the front link member 19 is non-rotatably fixed to the outer end of the front torsion shaft 27 of the torsion shafts 27, 28, while the rear torsion shaft 28 of the torsion shafts 27, 28 is fixed. The upper end of the rear link member 20 is fixed to the outer end of the non-rotatably. That is, the torsion shafts 27 and 28 constitute upper end pivot shafts of the link members 19 and 20.

  In other words, the torsion shafts 27 and 28 are pivotally supported by the portion fixed to the boss portion 29 on the traveling machine body 11 side, the mounting flange portion 18 and the like by the rotation of the link members 19 and 20. It is configured to be elastically twisted and deformed between the two parts.

The front link member 19 of the pair of front and rear link members 19 and 20 has a lower end rotatably connected to the track frame 17 by a lower pivot shaft 30, and the lower pivot shaft 30 is a front torsion at the upper end. We are inclined in front side obliquely downward direction so as to be positioned in front of the shaft 2 7 (upper pivot axis).

  The lower end of the rear link member 20 of the pair of front and rear link members 19 and 20 is rotatably connected to a support shaft 24 of the rear driven wheel body 23 of the track frame 17. That is, the support shaft 24 of the rear driven wheel body 23 constitutes the lower pivot shaft at the lower end of the rear link member 20.

Further, the rear link member 20 is inclined to the support shaft 24 (lower pivot axis) Backward obliquely downward direction so as to be positioned on the rear side of the rear torsion shaft 28 (upper pivot axis) at the top in its lower end Thus, the pair of front and rear link members 19 and 20 are arranged in a letter C shape spreading downward in the side view of the tractor 10 (FIGS. 1 and 2).

  The crawler traveling device 13 has a distance S1 from the vertical line 31 passing through the rear axle 15 to the front driven wheel body 21 in the side view of the tractor 10 (FIGS. 1 and 3). It is configured in a substantially triangular shape that is larger than the distance S2 to the moving wheel body 23.

  In this configuration, the track frame 17 in the crawler traveling device 13 receives the forward reaction force Pf from the ground as shown in FIG. When the tractor 10 travels backward, it receives the backward reaction force Pb from the ground and moves backward with respect to the traveling machine body 11.

  When the track frame 17 moves forward with respect to the traveling body 11, the front link member 19 of the pair of front and rear link members 19 and 20 has a torsion shaft 27 (upper pivot shaft) at its upper end. The rear link member 20 is tilted from the horizontal plane with the torsion shaft 28 (upper pivot shaft) at the upper end as a fulcrum (center) as the fulcrum (center). By turning in the direction to stand up so that the angle increases, it tilts forward.

  When the track frame 17 moves rearward with respect to the traveling body 11, the front link member 19 of the pair of front and rear link members 19 and 20 has a torsion shaft 27 (upper end pivot shaft) at its upper end. ) As a fulcrum (center), and the rear link member 20 is rotated in a standing direction so that the inclination angle from the horizontal plane is increased. By tilting in such a way that the tilt angle from the angle becomes small, it tilts backward.

  As a result, the track frame 17 is inclined forward and upward with respect to the traveling machine body 11 when traveling forward, and inclined backward when traveling backward.

  The forward and backward tilting motions of the track frame 17 cause torsional deformation of the torsion shafts 27 and 28 at the upper ends of the link members 19 and 20 against their torsional elasticity. Accordingly, when the forward traveling and the backward traveling are stopped, the track frame 17 is returned to the original position by the torsional elastic force of both the torsion shafts 27 and 28.

  Further, a restricting means 32 is provided between the track frame 17 and the rear axle case 14 or the flange portion 18 or the like so as to restrict the forward / backward movement of the track frame 17 to a predetermined distance. Yes.

  For example, as shown in the figure, the restricting means 32 slides a pin 34 at the tip of a stopper arm 33 extending downward from the rear axle case 14 into a long slot 36 in a stopper plate 35 fixed to the upper surface of the track frame 17. Of course, the restricting means 32 is not limited to the configuration shown in the drawing, and other configurations can be used.

  When the traveling machine body 11 is pitched, the traveling machine body 11 is moved by an appropriate unit angle θ1 (for example, θ1 = 15 degrees as in the prior art, as shown by a two-dot chain line in FIG. 6). When the front link member 19 is pitched so that its front part is lowered, the front link member 19 of the pair of front and rear link members 19 and 20 is lower than the lower end pivot of the front link member 19 with respect to the track frame 17 that is in contact with the ground. The rear link member 20 is supported at the lower end of the rear link member 20 with respect to the track frame 17 while rotating so that the inclination angle from the horizontal plane becomes smaller with the landing shaft 30 as a fulcrum (center). By rotating the shaft 24 (lower pivot shaft) as a fulcrum (center) so as to increase the inclination angle from the horizontal plane, the rear axle 15 is , Move backward by a distance E1.

  In addition, as shown by the dotted line in FIG. 7, the traveling machine body 11 is pitched so that its front part is raised by an appropriate unit angle θ2 (for example, θ2 = 15 degrees as in the case of the prior art). The front link member 19 of the pair of front and rear link members 19 and 20 is horizontal with respect to the track frame 17 that is in contact with the ground, with the lower pivot shaft 30 of the front link member 19 as a fulcrum (center). The rear link member 20 rotates with respect to the track frame 17 with a support shaft 24 (lower end pivot shaft) at the lower end of the rear link member 20. The rear axle 15 moves forward by a distance E2 by pivoting in a direction that tilts so that the inclination angle from the horizontal plane becomes small as a fulcrum (center).

  By the way, the part (flange part 18) between the torsion shafts 27 and 28 (upper pivot shaft) at the upper ends of the link members 19 and 20 in the traveling machine body 11, the pair of front and rear link members 19 and 20; In the four-joint link mechanism constituted by the track frame 17, the “instantaneous center” when the track frame 17, which is one of the nodes, moves in the longitudinal direction is an extension line 19 ′ in the front link member 19. And the extension line 20 ′ of the rear link member 20 are located at the intersection C, and the track frame 17 moves in the longitudinal direction about the “instantaneous center”.

  In this case, the pair of front and rear link members 19 and 20 are arranged in a downwardly widened C-shape, so that the instantaneous center is when the traveling machine body 11 is pitched forwardly downward by a unit angle θ1. As shown in FIG. 6, when moving from C to C 'and the traveling body 11 is pitched upward by the unit angle θ2, as shown in FIG. 7, it moves from C to C ″. The rear axle 15 can be held at a height that approximates the height of the rear axle 15.

  As a result, when the traveling machine body 11 pitches, the distances E1 and E2 that move back and forth with respect to the track frame 17 to which the traveling machine body 11 comes into contact are more than the rear axle 15 as in the prior art shown in FIG. The distance can be significantly reduced compared to the longitudinal movement distances L1 and L2 in the case of rotating around the swing fulcrum shaft positioned below.

  The torsion shafts 27, 28 at the upper ends of the link members 19, 20 act elastically against the pitching of the traveling machine body 11, and the restricting means 32 is also used for the pitching of the traveling machine body 11. Needless to say, it works against this.

  In addition, although embodiment of the said illustration was a case where it comprised to each torsion shaft 27,28 of the upper end pivot shaft in the said front link member 19 and the rear link member 20, this invention is not restricted to this, Of course, only one of the upper end pivot shafts of the front link member 19 and the rear link member 20 may be a torsion shaft. Further, the upper and lower ends of the front and rear link members 19 and 20 can be configured to be rotatable.

DESCRIPTION OF SYMBOLS 10 Tractor 11 Traveling machine body 12 Front wheel 13 Rear wheel crawler traveling device 14 Rear axle case 15 Rear axle 16 Driving wheel body 17 Track frame 18 Flange portion of rear axle case 19 Front link member 20 Rear link member 21 Front driven wheel body 23 Rear Follower wheel 24 Support shaft of rear follower wheel (lower pivot shaft)
25 Endless belt 27, 28 Upper end pivot axis (torsion axis)
30 Lower pivot shaft 32 Control means

Claims (4)

A traveling vehicle supported by the front wheels, a driving wheel mounted on the rear axle of the rear axle case at the rear of the traveling vehicle, a track frame disposed below the driving wheel, and a front and rear mounted on the truck frame A crawler traveling device for a rear wheel, comprising a front driven wheel body and a rear driven wheel body, wherein the drive wheel body, the front driven wheel body and the rear driven wheel body are wound with an endless belt-like body,
The track frame can be moved forward and backward by a front link member disposed on the front side of the rear axle and a rear link member disposed on the rear side of the rear axle on a traveling body including the rear axle case. is connected to the front link member, while its lower end pivot axis is inclined to the front side obliquely downward direction so as to be located forward of the upper pivot axis, the rear link member, the lower end pivot axis crawlers for the rear wheels in the running vehicle, characterized in that it is inclined rearwardly how obliquely downward direction so as to be positioned on the rear side of the upper pivot axis.   2. The rear wheel crawler in a traveling vehicle according to claim 1, wherein the lower pivot shaft of the rear link member is a support shaft for the track frame in the rear driven wheel. Traveling device.   In the claim 1 or 2, a restriction means for restricting forward and backward movement of the track frame to a predetermined distance is provided between the traveling machine body and the track frame. A crawler traveling device for a rear wheel in a traveling vehicle.   In any one of the said Claims 1-3, either one or both of the upper-end pivot shaft in the said front link member and the upper-end pivot shaft in the said rear link member is parallel to the said rear axle with the said traveling body. A crawler traveling device for a rear wheel in a traveling vehicle, characterized by comprising a torsion shaft disposed so as to extend in the direction.

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