JP2024157599A - Running gear for tracked vehicle, and tracked vehicle - Google Patents

Abstract

To reduce shocks when driving on rough roads.
[Solution] The running gear comprises a track frame arranged on the side of the vehicle body frame, a first arm member attached to the track frame so that its front and rear ends can swing up and down alternately, a first underrolling wheel rotatably attached to the front end of the first arm member, a rear end idler rotatably attached to the rear end of the first arm member, multiple running wheels provided at the front and rear of the track frame, and a track wrapped around the first underrolling wheel, the rear end idler and the multiple running wheels, and in a side view, the rear center distance between the swing center of the first arm member and the rotation center of the rear end idler is longer than the front center distance between the swing center of the first arm member and the rotation center of the first underrolling wheel.
[Selected figure] Figure 3

Description

The present invention relates to a running gear for a tracked vehicle and a tracked vehicle.

Some tracked vehicles are equipped with a structure that allows the underwheel to follow vertical changes in the track caused by ground undulations while the vehicle is traveling. Patent Document 1 discloses a structure that includes a track frame, a first arm member attached to the track frame, and first and second elastic abutment parts that are provided between the first arm member and the track frame and can elastically abut against each other. The support axis of the elastic support part is inclined in the fore-aft direction. The perpendicular line of the abutment surfaces of the first and second elastic abutment parts is inclined in the fore-aft direction in the same direction as the support axis of the elastic support part.

JP 2007-1377 A

However, tracked vehicles often travel on uneven terrain, and are subject to a large impact when they go over an obstacle and fall. For example, when the vehicle goes over a large block while reversing on rough roads, a force is generated pushing part of the first arm member in the forward and upward direction. In this case, depending on the configuration of the first arm member, it may not be possible to fully absorb the impact. Therefore, there is room for improvement in reducing the impact when reversing on rough roads.

The present invention aims to provide a running gear for a tracked vehicle and a tracked vehicle that can reduce shocks when traveling on rough roads.

The running gear of a tracked vehicle according to one aspect of the present invention comprises a track frame disposed on the side of a vehicle body frame, a first arm member attached to the track frame so that its front and rear ends can alternately swing up and down, a first lower roller rotatably attached to the front end of the first arm member, a rear end idler rotatably attached to the rear end of the first arm member, multiple running wheels provided at the front and rear of the track frame, and a track wound around the first lower roller, the rear end idler, and the multiple running wheels, and in a side view, the rear center distance between the swing center of the first arm member and the rotation center of the rear end idler is longer than the front center distance between the swing center of the first arm member and the rotation center of the first lower roller.

The above aspect can reduce shocks when reversing on rough roads.

FIG. FIG. FIG. 4 is a side view of a structure including a first arm member according to an embodiment. FIG. FIG. 13 is a diagram showing a structure according to a comparative example.

Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, a construction vehicle such as a bulldozer that works on rough ground will be used as an example of a tracked vehicle.

In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," do not only mean such arrangements or states in a strict sense, but also include arrangements or states in which there is a relative displacement with an angle or distance that allows tolerance or the same function to be obtained. In the drawings used in the following description, the scale of each component may be changed as appropriate to make each component large enough to be recognized.

<Tracked vehicle>
FIG. 1 is a side view of a tracked vehicle 1 according to an embodiment.
As shown in FIG. 1 , the tracked vehicle 1 includes a cab 2 , a body frame 3 on which the cab 2 is mounted, a working mechanism 4 , and a pair of traveling devices 5 .

Hereinafter, the forward direction (front of the vehicle body), backward direction (rear of the vehicle body) and vehicle width direction (left and right direction of the vehicle body) of the tracked vehicle 1 will be referred to as "front of the vehicle (one side in the front-rear direction of the vehicle)", "rear of the vehicle (the other side in the front-rear direction of the vehicle)" and "vehicle width direction". The vehicle width direction may also be referred to as "left side (one side in the vehicle width direction)" or "right side (the other side in the vehicle width direction)". The right side in the forward direction of the tracked vehicle 1 will be referred to as the right side, and the left side in the forward direction of the tracked vehicle 1 will be referred to as the left side. The vehicle up-down direction (up-down direction of the vehicle body), the vehicle top (upper side of the vehicle body) and the vehicle bottom (lower side of the vehicle body) of the tracked vehicle 1 will be referred to simply as the "up-down direction", "up" and "down". In the example shown in the figure, the tracked vehicle 1 is placed on a horizontal plane (level ground). The vehicle up-down direction (vehicle body up-down direction), vehicle top (vehicle body up) and vehicle bottom (vehicle body down) of the tracked vehicle 1 respectively correspond to the up-down direction (vertical direction), vertical top and vertical bottom when the tracked vehicle 1 is placed on a horizontal plane.

<Driver's cab>
For example, the cab 2 is equipped with a seat for the driver of the tracked vehicle 1, as well as levers, pedals, and instruments for various operations. The bottom of the cab 2 is formed by a floor frame 10. Pillars and side panels are placed on the floor frame 10. The floor frame 10 is shaped such that a step is provided in the middle in the fore-and-aft direction so that the front is low and the rear is high. The floor frame 10 is composed of a low floor section 11 on the front side and a high floor section 12 on the rear side.

<Vehicle frame>
An operating mechanism 4 and a traveling device 5 are attached to a body frame 3. A cab 2 is placed on the upper rear part of the body frame 3. A main frame (not shown) is provided on the lower part of the body frame 3. Although not shown, an engine, a torque converter, a transmission, etc. are also provided on the body frame 3. Driving force generated by the engine is transmitted to a sprocket 32 of the traveling device 5.

The vehicle body frame 3 is not limited to being provided with an engine or the like as a power source. For example, the vehicle body frame 3 may be provided with an electric motor or the like as a power source. For example, the traveling device 5 may travel by transmitting power from a power source such as an internal combustion engine or an electric motor to the tracks 50. For example, the type of power source can be changed depending on the design specifications.

Elastic support parts 15, 16 that elastically support the cab 2 from below are provided between the cab 2 and the vehicle body frame 3. For example, the elastic support parts 15, 16 are liquid-filled rubber mount devices in which a damping fluid is sealed inside a case and a support shaft protrudes from the center of the top surface of the case. The support shaft is fixed to the cab 2. The case is fixed to the vehicle body frame 3.

The elastic support parts 15, 16 are a pair of front elastic support parts 15 that support the front part of the cab 2, and a pair of rear elastic support parts 16 that support the rear part of the cab 2.

The front elastic support parts 15 are fixed to the left and right ends of the underside of the low floor part 11 of the floor frame 10 via brackets and bolts, etc. In the example shown in the figure, the front elastic support parts 15 are fixed to the underside of the low floor part 11 so that the axis 17 of the support shaft (hereinafter also referred to as the "front support axis 17") is aligned vertically. Note that the direction along which the front support axis 17 follows is not limited to the above and can be changed according to the design specifications.

The rear elastic support parts 16 are fixed to the left and right ends of the underside of the raised floor part 12 of the floor frame 10 by means of brackets and bolts, etc. In the example shown in the figure, the rear elastic support parts 16 are fixed to the underside of the raised floor part 12 so that the axis 18 of the support shaft (hereinafter also referred to as the "rear support axis 18") is inclined forward with respect to the vertical direction. In the example shown in the figure, the inclination angle A1 of the rear support axis 18 with respect to the vertical direction is approximately 15 degrees. Note that the direction along which the rear support axis 18 runs (inclination angle A1) is not limited to the above and can be changed according to the design specifications.

<Working mechanism>
The working mechanism 4 is a mechanism for scraping the ground and pushing away soil and sand. The working mechanism 4 includes a blade 20 and support frames 21, 22 that support the blade 20. The blade 20 is provided in front of the body frame 3. The blade 20 has a plate-like shape with a curved front surface. One ends of the support frames 21, 22 are fixed to the blade 20. The other ends of the support frames 21, 22 are fixed to the body frame 3 or the traveling device 5.

<Running gear>
The traveling devices 5 are provided on the left and right lower parts of the body frame 3, respectively. The pair of traveling devices 5 are provided on the left and right outer sides of a main frame (not shown). The traveling devices 5 are capable of traveling on rough ground by an endless track 50. One of the pair of traveling devices 5 will be described below. The other traveling device 5 has the same structure as the first traveling device 5, so a detailed description thereof will be omitted.

Referring to both Figures 1 and 2, the traveling device 5 comprises a track frame 30 arranged on the side of the vehicle body frame 3, an idler 31 and a sprocket 32 which are running wheels, a first single bogie device 33, a second single bogie device 34, and multiple double bogie devices 35, 36, 37 each having a lower roller 41-48 supported rotatably and swingably on the lower part of the track frame 30, a carrier roller 40, and a track 50. The single bogie device is a bogie device with one swing arm. The double bogie device is a bogie device with two swing arms.

<Truck frame>
The track frame 30 is provided along the front-rear direction of the vehicle. The track frame 30 is disposed on the lower side of the vehicle body frame 3. A yoke 55 is attached to the front end of the track frame 30 so as to be movable in the front-rear direction and biased forward via a spring (one example of a biasing member) (not shown). The idler 31 is rotatably attached to the front end of the second single bogie device 34. The sprocket 32 is disposed near the rear end of the track frame 30. The sprocket 32 is rotatably attached to the rear of the vehicle body frame 3. The sprocket 32 rotates when driving force is transmitted from the engine.

The truck frame 30 comprises a frame body 60 arranged along the vehicle longitudinal direction, and a rear end frame 61 attached to the rear of the frame body 60. The rear end frame 61 has a portion for attaching the first arm member 70. The front upper portion of the rear end frame 61 is fixed to the rear end of the frame body 60. The left and right truck frames 30 are attached to a main frame (not shown) on the left and right central sides via pivot shafts 62. For example, the frame body 60 and the rear end frame 61 may be the same part. For example, the rear end frame 61 may be the rear end of the frame body 60.

<First single bogie device>
1 to 3, the first single bogie device 33 is provided on the rear lower part of the track frame 30 adjacent to the sprocket 32. The first single bogie device 33 includes a first arm member 70, a first lower roller 41, a rear end idler 80, and elastic abutment portions 81, 82.

The first arm member 70 is attached to the track frame 30 so that its front and rear ends can swing up and down alternately. The first arm member 70 has a pivotal support portion near the center of the first arm member 70 in the fore-and-aft direction, which is rotatably fixed to the track frame 30 by a pin 71 (hereinafter also referred to as the "center pin 71"). The first arm member 70 has a shape that extends diagonally downward and forward from the pivotal support portion to the front end, and diagonally upward and backward from the pivotal support portion to the rear end. By rotating the first arm member 70 around the center pin 71, the front and rear ends of the first arm member 70 can swing relative to the track frame 30 around the pivotal support portion.

The first roller 41 is rotatably attached to the front end of the first arm member 70 by a pin 72 (hereinafter also referred to as the "front end pin 72"). The first roller 41 can swing up and down as the front end of the first arm member 70 swings up and down. The first roller 41 moves up and down following the movement of the track 50.

The rear end idler 80 is rotatably attached to the rear end of the first arm member 70. The rear end idler 80 is rotatably attached to the rear end of the first arm member 70 by a pin 73 (hereinafter also referred to as the "rear end pin 73"). The rear end idler 80 corresponds to an idler provided on the rear end side of the track frame 30 (opposite the front idler 31 in the front-rear direction). The rear end idler 80 is arranged rearward of the first underwheel 41, the second underwheel 42, and the multiple other underwheels 43-48. The rear end idler 80 is arranged rearward of the multiple running wheels 40-48. The rear end idler 80 is arranged rearward of the sprocket 32. The rear end idler 80 can swing up and down by the rear end of the first arm member 70 swinging up and down. The rear end idler 80 moves up and down following the movement of the crawler belt 50.

In a side view, the rear center distance Lr between the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is longer than the front center distance Lf between the swing center Cm of the first arm member 70 and the rotation center Cf of the first lower roller 41. The rear center distance Lr corresponds to the length of the line segment connecting the rotation center of the center pin 71 and the rotation center of the rear end pin 73. The front center distance Lf corresponds to the length of the line segment connecting the rotation center of the center pin 71 and the rotation center of the front end pin 72.

In this embodiment, the rear center distance Lr is 1.5 to 2.5 times the front center distance Lf. In the example shown in the figure, the rear center distance Lr is approximately twice the front center distance Lf.

In this embodiment, in a normal state where the traveling device 5 is stationary on flat ground, the rotation center Cr of the rear end idler 80 is located above the swing center Cm of the first arm member 70. In a side view, the rotation center Cr of the rear end idler 80 is located at a position rotated counterclockwise at an angle Ar of 10 degrees or more and 20 degrees or less with respect to a virtual horizontal line Hm passing through the swing center Cm of the first arm member 70. In a side view, the angle Ar corresponds to the smallest angle among the angles formed by the virtual horizontal line Hm passing through the rotation center of the center side pin 71 and the line segment connecting the rotation center of the center side pin 71 and the rotation center of the rear end side pin 73. In the example shown in the figure, the angle Ar is about 15 degrees.

The elastic contact portions 81 and 82 are pads made of an elastic material provided on the track frame 30 and the first arm member 70 between the first arm member 70 and the track frame 30 in the swing direction of the front end of the first arm member 70. For example, the elastic contact portions 81 and 82 are formed from an elastic material such as natural rubber (an example of rubber). The elastic contact portions 81 and 82 elastically contact each other when the first arm member 70 moves in a direction approaching the track frame 30 (for example, rotates clockwise around the central pin 71). Hereinafter, of the pair of elastic contact portions 81 and 82, the elastic contact portion 81 provided on the first arm member 70 side is also referred to as the "first elastic contact portion 81," and the elastic contact portion 82 provided on the track frame 30 side is also referred to as the "second elastic contact portion 82."

The first elastic contact portion 81 is provided on the upper front portion of the first arm member 70. The first elastic contact portion 81 is disposed diagonally above and in front of the central pin 71. For example, the first elastic contact portion 81 may be fixed to the upper front portion of the first arm member 70 by a bolt or the like via a first bracket (not shown). For example, the first elastic contact portion 81 may have a shape that curves upward from the upper surface of the first bracket that is aligned with the horizontal plane in a side view.

The second elastic contact portion 82 is provided on the lower part of the track frame 30. For example, the second elastic contact portion 82 may be fixed to the lower part of the rear end frame 61 constituting the track frame 30 via a second bracket (not shown) with a bolt or the like. For example, the second elastic contact portion 82 may have a shape that curves downward from the lower surface of the second bracket that is aligned with the horizontal plane in a side view.

In the example shown in the figure, the contact surface where the first elastic contact portion 81 and the second elastic contact portion 82 contact is disposed diagonally above and in front of the central pin 71. The perpendicular line N1 of the contact surface is disposed in front of the central pin 71 and behind the front end pin 72. The perpendicular line N1 of the contact surface is generally parallel to the vertical direction. The perpendicular line N1 of the contact surface corresponds to the normal line of the curved surface of each elastic contact portion 81, 82 at the first contact point when the elastic contact portions 81, 82 contact each other. The perpendicular line N1 of the contact surface may be inclined at a predetermined angle forward with respect to the vertical direction. For example, the direction along which the perpendicular line N1 of the contact surface follows (the inclination angle) is not limited to the above and can be changed according to the design specifications.

In a normal state where the traveling device 5 is stationary on flat ground, the first elastic abutment portion 81 and the second elastic abutment portion 82 are pressed together by the weight of the vehicle body frame 3, the driver's cab 2, etc., and abut against each other. In a normal state, the perpendicular line N1 of the abutment surface of each elastic abutment portion 81, 82 is generally parallel to the vertical direction, as described above. The abutment between the first elastic abutment portion 81 and the second elastic abutment portion 82 limits the rotation of the first arm member 70 (specifically, the upward swing of the front end portion of the first arm member 70). The abutment between the first elastic abutment portion 81 and the second elastic abutment portion 82 receives the load on the first lower roller 41, and further absorbs the impact received by the first lower roller 41.

<Second single bogie device>
2, the second single bogie device 34 is provided on the front lower part of the track frame 30 adjacent to the idler 31, and is rotatably attached to the yoke 55 by a pin 93. The second single bogie device 34 includes the idler 31, a second arm member 90, a second lower roller 42, and elastic abutment portions 91, 92.

The second arm member 90 is attached to the lower part of the yoke 55 so that its tip can swing up and down. The second arm member 90 has a base end that is rotatably fixed to the yoke 55 by a pin 93. The second arm member 90 has a shape that extends diagonally downward and rearward from the base end to the tip. By rotating the second arm member 90 around the pin 93, the tip of the second arm member 90 can swing relative to the yoke 55 around the base end.

The second roller 42 is rotatably attached to the rear end of the second arm member 90. The second roller 42 is positioned closest to the idler 31 (i.e., the frontmost) among the first roller 41, the second roller 42, and the other rollers 43-48. The second roller 42 is positioned diagonally below and rearward of the idler 31 in a side view. The tip of the second arm member 90 swings up and down, allowing the second roller 42 to swing up and down. The second roller 42 moves up and down following the movement of the track 50.

The elastic contact portions 91, 92 are pads made of an elastic material provided on the track frame 30 and the second arm member 90 between the second arm member 90 and the track frame 30 in the swing direction of the tip of the second arm member 90. For example, the elastic contact portions 91, 92 are formed from an elastic material such as natural rubber (an example of rubber). Hereinafter, of the pair of elastic contact portions 91, 92, the elastic contact portion 91 provided on the second arm member 90 side is also referred to as the "third elastic contact portion 91," and the elastic contact portion 92 provided on the track frame 30 side is also referred to as the "fourth elastic contact portion 92."

The third elastic abutment portion 91 is provided on the upper surface of the second arm member 90. The third elastic abutment portion 91 is disposed above the rear end portion of the second arm member 90. For example, the third elastic abutment portion 91 may have a shape parallel to the upper surface of the second arm member 90 that is aligned along a horizontal plane in a side view.

The fourth elastic abutment portion 92 is provided on the lower part of the track frame 30. For example, the fourth elastic abutment portion 92 may be fixed to the lower part of the track frame 30 by a bolt or the like via a bracket (not shown). For example, the fourth elastic abutment portion 92 may have a shape parallel to the lower surface of the bracket that is aligned along the horizontal plane in a side view.

For example, the contact surface where the third elastic contact portion 91 and the fourth elastic contact portion 92 contact is provided approximately parallel to a horizontal plane. The perpendicular line N2 of the contact surface is approximately parallel to the vertical direction. The perpendicular line N2 of the contact surface may be inclined forward at a predetermined angle with respect to the vertical direction. For example, the direction (inclination angle) of the perpendicular line N2 of the contact surface is not limited to the above and can be changed according to the design specifications.

In a normal state where the traveling device 5 is stationary on flat ground, the third elastic abutment portion 91 and the fourth elastic abutment portion 92 are pressed together by the weight of the vehicle body frame 3, the driver's cab 2, etc., and abut against each other. In a normal state, the abutment surfaces of the elastic abutment portions 91, 92 are generally parallel to the horizontal plane. In a normal state, the perpendicular line N2 of the abutment surfaces of the elastic abutment portions 91, 92 is generally parallel to the vertical direction. The abutment between the third elastic abutment portion 91 and the fourth elastic abutment portion 92 restricts the upward rotation of the second arm member 90. The abutment between the third elastic abutment portion 91 and the fourth elastic abutment portion 92 receives the load on the second lower roller 42, and further absorbs the impact received by the second lower roller 42.

<Double bogie device>
2, a plurality of double bogie devices 35, 36, 37 are provided between the first single bogie device 33 and the second single bogie device 34. In the example shown in the figure, three double bogie devices 35, 36, 37 are arranged in a line in the front-rear direction between the first single bogie device 33 and the second single bogie device 34. Note that the number of double bogie devices 35, 36, 37 is not limited to the above and can be changed according to design specifications.

Below, the structure of one of the double bogie devices 35, 36, 37 (double bogie device 35) will be explained, but the other double bogie devices 36, 37 have a similar structure.
The double bogie device 35 comprises a third arm member 100, a fourth arm member 101, a third lower roller 43, a fourth lower roller 44, and elastic abutment portions 102, 103.

The third arm member 100 is attached to the bottom of the track frame 30 so that its tip can swing up and down. The third arm member 100 has a base end that is rotatably fixed to the track frame 30 by a pin 104. The third arm member 100 has a shape that extends diagonally downward and rearward from the base end to the tip. By rotating the third arm member 100 around the base end of the third arm member 100, the tip of the third arm member 100 can swing relative to the track frame 30 around the base end. The other double bogie devices 36, 37 also have arm members similar to the third arm member 100, and the arm members are arranged side by side in the front-to-rear direction.

The fourth arm member 101 is rotatably attached to the tip of the third arm member 100 by a pin 105 at approximately the center of the fourth arm member 101. The fourth arm member 101 has a shape that extends in the front-rear direction from approximately the center to both ends, centered on the pin 105. By rotating the fourth arm member 101 around the pin 105, both ends of the fourth arm member 101 can swing up and down alternately. The other double bogie devices 36, 37 also have arm members similar to the fourth arm member 101, and the arm members are arranged side by side in the front-rear direction.

The third roller 43 is rotatably attached to the front end of the fourth arm member 101. The fourth roller 44 is rotatably attached to the rear end of the fourth arm member 101. The third roller 43 and the fourth roller 44 are arranged symmetrically (in other words, symmetrically in the longitudinal direction of the vehicle) about the pin 105 in a side view. The other double bogie devices 36, 37 also have rollers similar to the third roller 43 and the fourth roller 44, and the rollers are arranged side by side in the longitudinal direction together with the first roller 41 and the second roller 42.

The elastic contact portions 102, 103 are pads made of an elastic material provided on the track frame 30 and the third arm member 100 between the third arm member 100 and the track frame 30 in the swing direction of the tip of the third arm member 100. For example, the elastic contact portions 102, 103 are formed from an elastic material such as natural rubber (an example of rubber). Hereinafter, of the pair of elastic contact portions 102, 103, the elastic contact portion 102 provided on the third arm member 100 side is also referred to as the "fifth elastic contact portion 102," and the elastic contact portion 103 provided on the track frame 30 side is also referred to as the "sixth elastic contact portion 103."

The fifth elastic contact portion 102 is provided on the upper surface of the third arm member 100. The fifth elastic contact portion 102 is disposed above the pin 105 at the tip of the third arm member 100. For example, the fifth elastic contact portion 102 may have a shape parallel to the upper surface of the third arm member 100 along a horizontal plane in a side view.

The sixth elastic contact portion 103 is provided on the lower part of the track frame 30. For example, the sixth elastic contact portion 103 may be fixed to the lower part of the track frame 30 by a bolt or the like via a bracket (not shown). For example, the sixth elastic contact portion 103 may have a shape parallel to the lower surface of the bracket that is aligned with the horizontal plane in a side view.

For example, the contact surface where the fifth elastic contact portion 102 and the sixth elastic contact portion 103 contact each other is provided generally parallel to a horizontal plane. The perpendicular line N3 of the contact surface is generally parallel to the vertical direction. The perpendicular line N3 of the contact surface may be inclined forward at a predetermined angle with respect to the vertical direction. For example, the direction (inclination angle) of the perpendicular line N3 of the contact surface is not limited to the above and can be changed according to the design specifications.

In a normal state where the traveling device 5 is stationary on flat ground, the fifth elastic abutment portion 102 and the sixth elastic abutment portion 103 are pressed together by the weight of the vehicle body frame 3, the driver's cab 2, etc., and abut against each other. In a normal state, the abutment surfaces of the elastic abutment portions 102 and 103 are generally parallel to the horizontal plane. In a normal state, the perpendicular line N3 of the abutment surfaces of the elastic abutment portions 102 and 103 is generally parallel to the vertical direction. The abutment between the fifth elastic abutment portion 102 and the sixth elastic abutment portion 103 restricts the upward rotation of the third arm member 100. The abutment between the fifth elastic abutment portion 102 and the sixth elastic abutment portion 103 receives the load on the third lower roller 43 and the fourth lower roller 44, and further absorbs the impact received by the third lower roller 43 and the fourth lower roller 44.

＜Upper Roller＞
2, the carrier roller 40 is one (the upper one) of a plurality of running wheels provided at the front and rear of the track frame 30. The carrier roller 40 is provided at the upper part of the track frame 30, between the idler 31 and the sprocket 32. The carrier roller 40 is supported rotatably by a pin 110. In the example shown in the figure, one carrier roller 40 is provided. Note that the number of carrier rollers 40 provided is not limited to the above and can be changed according to the design specifications.

<Track>
2, the crawler belt 50 is wound around the first underwheel 41, the rear end idler 80, the second underwheel 42, the other underwheels 43-48, the idler 31, the sprocket 32, and the carrier roller 40. For example, the crawler belt 50 is formed in an endless shape by connecting a plurality of plate-shaped shoes. The crawler belt 50 includes a plurality of links 51.

<Stopper part>
2 and 3 , the traveling device 5 includes stopper portions 121, 122 provided on the track frame 30 and the first arm member 70, respectively, between the first arm member 70 and the track frame 30 in the swing direction of the rear end portion of the first arm member 70. The stopper portions 121, 122 come into contact with each other when the first arm member 70 moves in a direction approaching the track frame 30 (specifically, rotates counterclockwise around the central pin 71).

The stopper portions 121, 122 include a first arm member side protrusion 121 provided on the first arm member 70 and a track frame side receiving portion 122 provided on the track frame 30. The first arm member side protrusion 121 protrudes upward from the rear upper surface of the first arm member 70. The track frame side receiving portion 122 corresponds to the upper surface of a recess formed so as to recess upward from the rear lower portion of the rear end frame 61 that constitutes the track frame 30. When the first arm member 70 swings so that the rear end of the first arm member 70 is displaced upward, the first arm member side protrusion 121 comes into contact with the track frame side receiving portion 122, thereby stopping the swing of the first arm member 70.

In a normal state where the traveling device 5 is stationary on flat ground, the first arm member side convex portion 121 and the truck frame side receiving portion 122 are separated from each other. For example, when the first arm member 70 rotates about 5 to 10 degrees around the central pin 71 so that the rear end of the first arm member 70 is displaced upward, the first arm member side convex portion 121 abuts against the truck frame side receiving portion 122. The abutment between the first arm member side convex portion 121 and the truck frame side receiving portion 122 limits the rotation of the first arm member 70 (specifically, the upward swing of the rear end of the first arm member 70). The abutment between the first arm member side convex portion 121 and the truck frame side receiving portion 122 receives the load applied to the rear end idler 80, and further absorbs the impact received by the rear end idler 80.

The stopper portions 121, 122 may further include a pad made of an elastic material (hereinafter also referred to as a "first elastic pad") between the first arm member side protrusion 121 and the track frame side receiving portion 122. For example, the first elastic pad may be provided on each of the first arm member side protrusion 121 and the track frame side receiving portion 122. For example, the installation mode of the first elastic pad can be changed according to the design specifications.

<Function of the structure according to the embodiment>
First, the structure according to the embodiment will be described.
Referring to FIG. 4, the structure according to the embodiment has a single bogie at the front of the first arm member 70 .
In a side view, the rear center distance Lr between the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is longer than the front center distance Lf between the swing center Cm of the first arm member 70 and the rotation center Cf of the first lower roller 41 (Lr>Lf). In the illustrated example, the rear center distance Lr is approximately twice the front center distance Lf.

When the traveling device 5 is in a normal state where it is stationary on flat ground, the rotation center Cr of the rear end idler 80 is located above the swing center Cm of the first arm member 70. In the example shown in the figure, the rotation center Cr of the rear end idler 80 is located at a position rotated approximately 15 degrees counterclockwise with respect to the imaginary horizontal line Hm that passes through the swing center Cm of the first arm member 70.

Next, a structure according to a comparative example will be described.
Referring to FIG. 5, the structure according to the comparative example has a double bogie at the front of the first arm member 270 .
In a side view, the rear center distance Lr between the swing center Cm of the first arm member 270 and the rotation center Cr of the rear end idler 80 is shorter than the front center distance Lf between the swing center Cm of the first arm member 270 and the rotation center Cf of the double bogie (Lr<Lf). In the illustrated example, the rear center distance Lr is approximately 1/2 of the front center distance Lf.

When the traveling device 5 is in a normal state where it is stationary on flat ground, the rotation center Cr of the rear end idler 80 is located below the swing center Cm of the first arm member 270. In the example shown in the figure, the rotation center Cr of the rear end idler 80 is located at a position rotated about 10 degrees clockwise with respect to the imaginary horizontal line Hm that passes through the swing center Cm of the first arm member 270.

<Differences in function and effect from comparative examples>
For example, when the vehicle reverses over a large block while traveling on a rough road, a thrust force is generated in the forward and upward direction (the direction of arrow F in the figure) on the rear end idler 80 at the rear end of the first arm member. In this case, the impact load on the rear end idler 80 is generated in a direction rotated about 15 degrees counterclockwise from the vertical line.

In the comparative example structure of FIG. 5, the angle Af between the direction F of the thrust force on the rear end idler 80 and the line connecting the swing center Cm of the first arm member 270 and the rotation center Cr of the rear end idler 80 is an obtuse angle. In the comparative example structure, the torque in the reverse direction around the pin due to the force applied to the rear end idler 80 tends to be larger than the torque due to the thrust force. Therefore, the translational thrust motion is difficult to convert into rotational motion of the first arm member 270, making it difficult to dissipate the impact.

In contrast, in the structure according to the embodiment of FIG. 4, the angle Af between the direction F of the thrust force on the rear end idler 80 and the line connecting the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is approximately a right angle. In the case of the structure according to the embodiment, when a force acting on the rear end idler 80, such as a thrust force, acts, rotational motion is facilitated. Therefore, the translational thrust motion is easily converted into the rotational motion of the first arm member 70, and the impact is easily released. In other words, the first arm member 70 converts the thrust force of the translational force acting on the rear end idler 80 into a force in the rotational direction. As a result, the translational component of the force transmitted from the pin 71 to the track frame 30 is eliminated, and the force transmitted to the main frame 3 immediately after the collision is eliminated.

When the first arm member 70 rotates, the first lower roller 41 and the rear end idler 80 attached to the end of the first arm member 70 come into frictional contact with the link 51 of the track 50. This has the effect of damping the rotational motion of the first arm member 70.

In this embodiment, the rear center distance Lr is approximately twice the front center distance Lf, so that the rotational motion of the first arm member 70 can be easily converted when a thrust force is applied to the rear end idler 80. As a result, the vertical displacement of the rear end idler 80 and the vertical displacement of the first lower roller 41 create a balance effect, which reduces the vertical displacement and thrust force of the central pin 71 by half.

In this embodiment, in the swing direction of the left rotation of the first arm member 70, most of the translational force applied to the rear end idler 80 is replaced by the rotational component of the first arm member 70, and the first arm member 70 swings about 5 to 10 degrees. This allows a first stage shock absorbing mechanism to be provided. After the first arm member side convex portion 121 abuts against the truck frame side receiving portion 122, when further force is applied to the rear end idler 80, the truck frame 30 rotates counterclockwise around the pivot shaft 62 together with the first single bogie device 33. This allows a second stage shock absorbing structure to be provided that further absorbs impact force.

In the structure of the comparative example in FIG. 5, the rear center distance Lr is shorter than in the embodiment, and the stroke that can absorb the impact is shorter, making it difficult to release the impact. The acceleration (load) of the thrust force transmitted to the truck frame 30 of the embodiment is smaller than in the comparative example due to the difference in the structure described above. For example, the acceleration (load) of the thrust force transmitted to the truck frame 30 of the present embodiment is approximately 20% smaller than in the comparative example due to the difference in the structure described above.

In the structure of the comparative example in FIG. 5, the resonance frequency of the spring mass system is far removed from the representative vibration frequency during driving, and there is almost no dynamic damping effect when driving on flat roads or during ground leveling work.
In contrast, in the structure according to the embodiment of Fig. 4, the resonance frequency determined by the spring constant of the elastic contact parts 81, 82 and the rotational inertia around the pin 71 is adjusted to the frequency of pitching and bouncing, which are typical vibrations during driving, to provide a dynamic damping effect not found in the comparative example. In the embodiment, the dynamic damper described above can suppress the vibration level (pitching and bouncing vibration of the vehicle body) during driving on flat roads or during ground leveling work more than in the comparative example. For example, in this embodiment, the vibration level can be suppressed to about 1/4. Therefore, the ride comfort and ground leveling performance can be significantly improved.

<Action and effect>
As described above, the traveling device 5 of the tracked vehicle 1 of this embodiment includes the track frame 30 arranged on the side of the vehicle body frame 3, the first arm member 70 attached to the track frame 30 so that the front end and the rear end can alternately swing up and down, the first lower roller 41 rotatably attached to the front end of the first arm member 70, the rear end idler 80 rotatably attached to the rear end of the first arm member 70, a plurality of running wheels 42 to 48 provided at the front and rear of the track frame 30, and the crawler belt 50 wound around the first lower roller 41, the rear end idler 80 and the plurality of running wheels 42 to 48. In a side view, the rear center distance Lr between the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is longer than the front center distance Lf between the swing center Cm of the first arm member 70 and the rotation center Cf of the first lower roller 41.
For example, when the vehicle goes over a large block while reversing on a rough road, a thrust force is generated in the forward and upward direction against the rear end idler 80 at the rear end of the first arm member 70. If the rear center-to-center distance Lr is equal to or shorter than the front center-to-center distance Lf, the stroke that can absorb the impact is short, making it difficult to release the impact. In contrast, according to the present configuration, the rear center-to-center distance Lr is longer than the front center-to-center distance Lf, so that the stroke that can absorb the impact is long and the impact is easily released. Therefore, it is possible to reduce the impact when reversing on a rough road.

In this embodiment, the rear center distance Lr is 1.5 times or more and 2.5 times or less the front center distance Lf.
For example, if the rear center distance Lr is less than 1.5 times the front center distance Lf, a sufficient stroke is not obtained to absorb the impact, and it is difficult to release the impact. On the other hand, if the rear center distance Lr is more than 2.5 times the front center distance Lf, an excessive load is applied to the crawler belt 50, and the crawler belt 50 is likely to come off. In contrast, according to the present configuration, the rear center distance Lr is 1.5 to 2.5 times the front center distance Lf, so that the occurrence of the above problem can be suppressed. In this embodiment, the rear center distance Lr is 1.5 to 2.5 times the front center distance Lf, but is not limited to the above and can be changed according to the design specifications.

In this embodiment, in a normal state in which the traveling device 5 is stationary on flat ground, the rotation center Cr of the rear end idler 80 is disposed above the swing center Cm of the first arm member 70 .
For example, when the vehicle goes over a large mass while traveling backward on a rough road, a thrust force is generated in the forward and upward direction on the rear end idler 80 at the rear end of the first arm member 70. In this case, the impact load on the rear end idler 80 is generated in a direction rotated about 15 degrees counterclockwise from the vertical line. In a normal state in which the traveling device 5 is stationary on flat ground, when the rotation center Cr of the rear end idler 80 is disposed below the swing center Cm of the first arm member 70, the angle Af formed by the direction of the thrust force on the rear end idler 80 and the line connecting the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is an obtuse angle. Therefore, the thrust force generated in the forward and upward direction on the rear end idler 80 at the rear end of the first arm member 70 is difficult to convert into rotational motion, and the impact is difficult to escape. In contrast, according to the present configuration, in a normal state in which the traveling device 5 is stationary on flat ground, the rotation center Cr of the rear end idler 80 is positioned above the swing center Cm of the first arm member 70, so that the angle Af formed by the direction of the thrust force on the rear end idler 80 and the line connecting the swing center Cm of the first arm member 70 and the rotation center Cr of the rear end idler 80 is approximately a right angle. Therefore, the thrust force generated toward the front and upper direction on the rear end idler 80 at the rear end of the first arm member 70 is easily converted into rotational motion, making it easy to dissipate impact. Therefore, it is possible to more effectively reduce impact when traveling backward on rough roads.

In this embodiment, the running gear 5 of the tracked vehicle 1 further includes elastic abutment portions 81, 82 that are provided on at least one of the track frame 30 and the first arm member 70 between the first arm member 70 and the track frame 30 in the swinging direction of the front end of the first arm member 70 and are capable of elastically abutting against the other.
According to this configuration, the elastic contact portions 81, 82 can absorb impact between the first arm member 70 and the track frame 30 in the swing direction of the front end portion of the first arm member 70.

In this embodiment, the elastic contact portions 81, 82 are pads made of an elastic material provided on the track frame 30 and the first arm member 70, respectively.
According to this configuration, the impact can be efficiently absorbed and reduced by both the elastic pads provided on the track frame 30 and the first arm member 70 .

The tracked vehicle 1 of this embodiment comprises a cab 2, a body frame 3 on which the cab 2 is mounted, and a running gear 5 of the tracked vehicle 1 described above.
According to this configuration, by providing the above-mentioned running device 5 of the tracked vehicle 1, it is possible to reduce shocks when reversing on rough roads. Therefore, it is possible to improve the ride comfort of the tracked vehicle 1.

For example, in the conventional machine, there is no rear end idler 80, and instead there is a sprocket 32 connected to the main frame in its place. Therefore, in the conventional machine, when the vehicle goes over a large block while reversing on a rough road, the upward translational force is transmitted directly to the main frame from the sprocket 32. In the case of the conventional machine, the load on the main frame increases, and there is a concern that the ride quality may deteriorate.
In contrast, in this embodiment, most of the upward translational force is converted into torque around the pin 71 by the rotation of the first arm member 70. Therefore, the upward translational force transmitted to the track frame 30 is significantly reduced. As a result, the ride comfort of the tracked vehicle 1 can be improved.
In addition, in this embodiment, when the first arm member side convex portion 121 comes into contact with the truck frame side receiving portion 122, the thrust is transmitted to the main frame via the pivot shaft 62. In this embodiment, in addition to the transmission path to the driver's seat being longer, the two-stage shock absorbing structure can reduce the thrust to less than half of that of conventional machines.

For example, in this embodiment, the resonance frequency determined by the moment of inertia around the pin 71 of the first arm member 70, the first lower roller 41, and the rear end idler 80 and the spring constants of the first elastic abutment portion 81 and the second elastic abutment portion 82 is set to the link pitch frequency determined by the vehicle speed during ground leveling work. This makes it possible to configure a dynamic damper device that significantly reduces vibration.

For example, in this embodiment, the resonance frequency determined by the moment of inertia around the first arm member 70, the first lower roller 41, the front end pin 72, the rear end pin 73, and the central pin 71 of the rear end idler 80, and the spring constants of the first elastic abutment portion 81 and the second elastic abutment portion 82, is set close to the link pitch frequency determined by the vehicle speed during ground leveling work. This makes it possible to configure a dynamic damper device that significantly reduces vibration, and significantly reduces the pitching and bouncing vibrations of the vehicle.

<Modification>
In the above-described embodiment, the rear center distance is 1.5 to 2.5 times the front center distance, but is not limited thereto. For example, the rear center distance may be less than 1.5 times the front center distance. For example, the rear center distance may be more than 2.5 times the front center distance. For example, the rear center distance may be longer than the front center distance. For example, the ratio of the rear center distance to the front center distance may be changed according to the design specifications.

In the above embodiment, an example has been described in which the center of rotation of the rear end idler is located above the swing center of the first arm member in the normal state in which the traveling device is stationary on flat ground, but this is not limited to this. For example, in the normal state in which the traveling device is stationary on flat ground, the center of rotation of the rear end idler may be located at a position below or at the same height as the swing center of the first arm member. For example, the arrangement of the center of rotation of the rear end idler can be changed according to the design specifications.

In the above-described embodiment, the stopper portion includes a first arm member side convex portion provided on the first arm member, and a track frame side receiving portion provided on the track frame that contacts the first arm member side convex portion when the first arm member swings so that the rear end of the first arm member is displaced upward, thereby stopping the swing of the first arm member. However, this is not limited to the above. For example, the stopper portion may include a track frame side convex portion provided on the track frame, and a first arm member side receiving portion provided on the first arm member that contacts the track frame side convex portion when the first arm member swings so that the rear end of the first arm member is displaced upward, thereby stopping the swing of the first arm member. For example, the configuration of the stopper portion (the configuration of the convex portion and the receiving portion) can be changed according to the design specifications.

In the above-described embodiment, the traveling gear of the tracked vehicle is described as further including an elastic abutment portion that is provided on at least one of the track frame and the first arm member between the first arm member and the track frame in the swing direction of the front end of the first arm member and can elastically abut against the other, but this is not limited thereto. For example, the traveling gear of the tracked vehicle does not need to include an elastic abutment portion. For example, the installation manner of the elastic abutment portion can be changed according to the design specifications.

In the above-described embodiment, the elastic contact portion is an elastic pad provided on each of the track frame and the first arm member, but this is not limited to the above. For example, the elastic pad may be provided on either the track frame or the first arm member, but not on the other. For example, the installation mode of the elastic pad may be changed according to the design specifications.

The above-mentioned embodiment of the tracked vehicle has been described as having a cab, a body frame on which the cab is mounted, and the above-mentioned running gear of the tracked vehicle, but is not limited to this. For example, the tracked vehicle does not need to have a cab for a driver to ride in. For example, the tracked vehicle may be a manned tracked vehicle that is driven based on the driving operation by a driver, or an unmanned tracked vehicle that is driven without being driven by a driver. For example, the installation mode of the cab can be changed according to the design specifications.

In the above embodiment, the tracked vehicle is described as a bulldozer, but this is not limited to this. For example, the tracked vehicle may be other work vehicles such as a crawler dump, a shovel, or a tractor. For example, the configuration of the tracked vehicle can be changed according to the design specifications.

Although the embodiments of the present invention have been described above, the present invention is not limited to these, and additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention, and the above-mentioned embodiments can also be combined as appropriate.

(Appendix 1)
A truck frame disposed on a side of the vehicle body frame;
a first arm member attached to the truck frame such that a front end and a rear end of the first arm member can alternately swing up and down;
a first roller rotatably attached to the front end of the first arm member;
a rear end idler rotatably attached to the rear end of the first arm member;
A plurality of running wheels provided at the front and rear of the track frame;
a crawler belt wound around the first roller, the rear end idler, and the plurality of running wheels;
In a side view, a rear center distance between a swing center of the first arm member and a rotation center of the rear end idler is longer than a front center distance between the swing center of the first arm member and a rotation center of the first lower roller.
Running gear of a tracked vehicle.

(Appendix 2)
The first arm member converts a translational force acting on the rear end idler into a rotational force.
2. A running device for a tracked vehicle as described in claim 1.

(Appendix 3)
When viewed from the side, an angle formed by a direction of a force acting on the rear end idler and a line connecting the swing center of the first arm member and the rotation center of the rear end idler is a right angle.
3. A running device for a tracked vehicle according to claim 1 or 2.

(Appendix 4)
The rear center distance is 1.5 times or more and 2.5 times or less than the front center distance.
A running device for a tracked vehicle according to any one of appendixes 1 to 3.

(Appendix 5)
In a normal state in which the traveling device is stationary on a flat ground, the rotation center of the rear end idler is disposed above the swing center of the first arm member.
5. A running device for a tracked vehicle according to any one of claims 1 to 4.

(Appendix 6)
a stopper portion that limits the rotation of the first arm member when the rear end portion of the first arm member swings upward,
A running device for a tracked vehicle as described in any one of appendix 1 to 5.

(Appendix 7)
The stopper portion is
a first arm member side protrusion provided on the first arm member;
a track frame side receiving portion that is provided on the track frame and that, when the first arm member swings such that the rear end portion of the first arm member is displaced upward, comes into contact with the first arm member side convex portion to stop the swing of the first arm member,
7. A running device for a tracked vehicle as described in appendix 6.

(Appendix 8)
When the first arm member side protrusion comes into contact with the truck frame side receiving portion, and an additional force is applied to the rear end idler, the truck frame rotates integrally with the first arm member.
8. A running device for a tracked vehicle according to claim 7.

(Appendix 9)
a resilient contact portion provided on at least one of the track frame and the first arm member between the first arm member and the track frame in a swing direction of the front end portion of the first arm member and resilient to contact the other of the track frame and the first arm member;
A running device for a tracked vehicle according to any one of appendixes 1 to 8.

(Appendix 10)
The elastic contact portion is a pad made of an elastic material provided on each of the track frame and the first arm member.
10. A running device for a tracked vehicle as described in appendix 9.

(Appendix 11)
The driver's cab and
The vehicle body frame on which the driver's cab is placed; and
A running device for a tracked vehicle according to any one of appendices 1 to 10;
Tracked vehicle.

1...tracked vehicle, 2...driver's cab, 3...body frame, 5...running gear, 30...track frame, 40...upper roller (running wheel), 41...first lower roller, 42-48...lower roller (running wheel), 50...track, 60...frame body, 61...rear end frame, 70...first arm member, 80...rear end idler, 81...first elastic abutment portion, 82...second elastic abutment portion, 121...first arm member side protrusion (stop 122: Truck frame side receiving part (stopper part), Af: Angle between the direction of the force acting on the rear end idler in side view and the line connecting the swing center of the first arm member and the rotation center of the rear end idler, Cm: Rotation center of the central pin (swing center of the first arm member), Cf: Rotation center of the first lower roller, Cr: Rotation center of the rear end idler, Lf: Front center distance, Lr: Rear center distance

Claims (11)

A truck frame disposed on a side of the vehicle body frame;
a first arm member attached to the truck frame such that a front end and a rear end of the first arm member can alternately swing up and down;
a first roller rotatably attached to the front end of the first arm member;
a rear end idler rotatably attached to the rear end of the first arm member;
A plurality of running wheels provided at the front and rear of the track frame;
a crawler belt wound around the first roller, the rear end idler, and the plurality of running wheels;
In a side view, a rear center distance between a swing center of the first arm member and a rotation center of the rear end idler is longer than a front center distance between the swing center of the first arm member and a rotation center of the first lower roller.
Running gear of a tracked vehicle. The first arm member converts a translational force acting on the rear end idler into a rotational force.
A running device for a tracked vehicle according to claim 1. When viewed from the side, an angle formed by a direction of a force acting on the rear end idler and a line connecting the swing center of the first arm member and the rotation center of the rear end idler is a right angle.
A traveling device for a tracked vehicle according to claim 1 or 2. The rear center distance is 1.5 times or more and 2.5 times or less than the front center distance.
A traveling device for a tracked vehicle according to claim 1 or 2. In a normal state in which the traveling device is stationary on a flat ground, the rotation center of the rear end idler is disposed above the swing center of the first arm member.
A traveling device for a tracked vehicle according to claim 1 or 2. a stopper portion that limits the rotation of the first arm member when the rear end portion of the first arm member swings upward,
A traveling device for a tracked vehicle according to claim 1 or 2. The stopper portion is
a first arm member side protrusion provided on the first arm member;
a track frame side receiving portion that is provided on the track frame and that, when the first arm member swings such that the rear end portion of the first arm member is displaced upward, comes into contact with the first arm member side convex portion to stop the swing of the first arm member,
A traveling device for a tracked vehicle according to claim 6. When the first arm member side protrusion comes into contact with the truck frame side receiving portion, and an additional force is applied to the rear end idler, the truck frame rotates integrally with the first arm member.
A traveling device for a tracked vehicle according to claim 7. a resilient contact portion provided on at least one of the track frame and the first arm member between the first arm member and the track frame in a swing direction of the front end portion of the first arm member and resilient to contact the other of the track frame and the first arm member;
A traveling device for a tracked vehicle according to claim 1 or 2. The elastic contact portion is a pad made of an elastic material provided on each of the track frame and the first arm member.
A traveling device for a tracked vehicle according to claim 9. The driver's cab and
The vehicle body frame on which the driver's cab is placed; and
The traveling device of the tracked vehicle according to claim 1 or 2,
Tracked vehicle.

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