Tracked construction machinery

Abstract

In the bulldozer (1), when the controller (100) switches from stationary steering mode to straight-ahead mode or differential steering mode, it maintains the speed of the steering motor (80) up to the speed of the inner steering clutch (40). IN After the moment (t1) when the partial engagement begins.

Description

Technical Field

[0001] This disclosure relates to a tracked engineering machine. Background Technology

[0002] Previously, tracked construction machinery (e.g., bulldozers) with left and right planetary gear mechanisms, hydraulically driven left and right steering clutches, hydraulically driven left and right steering brakes, and steering motors were known (see Patent Document 1).

[0003] Left and right planetary gear mechanisms are positioned between the input shaft and the left and right output shafts. Left and right steering clutches can rotate around the input shaft, switching and disengaging the rotational power transmission from the input shaft to the left and right output shafts via the planetary gear mechanisms. Left and right steering brakes apply braking to the left and right output shafts. Steering motors rotate the left and right steering clutches by creating a speed difference between the left and right output shafts.

[0004] The tracked engineering machinery described in Patent Document 1 moves straight by engaging the left and right steering clutches, disengaging the left and right steering brakes, and stopping the steering motor.

[0005] The tracked engineering machinery described in Patent Document 1 turns in differential steering (slow turn) mode by engaging the left and right steering clutches, disengaging the left and right steering brakes, and driving the steering motor.

[0006] The tracked engineering machinery described in Patent Document 1 turns in a stationary turning mode by opening the inner steering clutch, braking the inner steering brake, and stopping the steering motor.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 53-27929 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, even in stationary steering mode, the steering speed can be increased by driving the steering motor.

[0012] In this situation, in stationary steering mode, since the inner steering clutch is disengaged, the inner planetary gear mechanism idles due to the rotational power from the input shaft, and the inner steering clutch also idles due to the driving force of the steering motor.

[0013] On the other hand, for example, when switching immediately from stationary steering mode to straight-ahead mode, the steering motor stops and the inner steering clutch engages. As the steering motor stops, the inner steering clutch also stops, thus increasing the relative speed of the inner steering clutch with respect to the inner planetary gear mechanism. If the inner steering clutch engages in this state, excessive thermal load may be generated in the inner steering clutch.

[0014] The purpose of this disclosure is to provide a tracked engineering machine capable of suppressing the thermal load on the inner steering clutch.

[0015] Solution for solving the problem

[0016] One aspect of this disclosure involves a tracked construction machine comprising a left and right planetary gear mechanism, left and right steering clutches, left and right steering brakes, a steering motor, and a controller. The left and right planetary gear mechanism is disposed between an input shaft and left and right output shafts. The left and right steering clutches are rotatable about the input shaft, switching and disengaging the transmission of rotational power from the input shaft to the left and right output shafts via the left and right planetary gear mechanism. The left and right steering brakes brake the left and right output shafts. The steering motor rotates the left and right steering clutches by creating a speed difference between the left and right output shafts. The controller controls the left and right steering clutches, left and right steering brakes, and steering motor to enable the tracked construction machine to steer in one of three modes: straight-line mode, differential steering mode, and stationary steering mode. In straight-line mode, the controller engages the left and right steering clutches, disengages the left and right steering brakes, and stops the steering motor. In differential steering mode, the controller engages the left and right steering clutches, disengages the left and right steering brakes, and drives the steering motor. In stationary steering mode, the controller disengages the inner steering clutch corresponding to the steering direction from the left and right steering clutches, brakes the inner steering brake corresponding to the steering direction from the left and right steering brakes, and drives the steering motor. When the controller switches from stationary steering mode to straight-line mode or differential steering mode, it maintains the speed of the steering motor until after the first moment when the inner steering clutch begins to engage.

[0017] Invention Effects

[0018] According to the technology disclosed herein, it is possible to provide a tracked engineering machine that can suppress the thermal load on the inner steering clutch. Attached Figure Description

[0019] Figure 1 This is a perspective view of the bulldozer used in the implementation method.

[0020] Figure 2 This is a cross-sectional structural diagram of the power transmission system of the bulldozer according to the implementation method.

[0021] Figure 3This is a schematic system structure diagram of the power transmission system of the bulldozer according to the implementation method.

[0022] Figure 4 This is a diagram illustrating a control example of a bulldozer based on a controller implemented in this way.

[0023] Figure 5 This is a diagram illustrating an example of the bulldozer's state when it immediately switches from stationary turning mode to straight-ahead mode.

[0024] Figure 6 This is a schematic system structure diagram of the power transmission system of the bulldozer in variation example 1. Detailed Implementation

[0025] (Exterior structure of bulldozer 1)

[0026] Figure 1 This is a perspective view of bulldozer 1, an example of tracked construction machinery. Figure 2 This is a cross-sectional structural diagram of the power transmission system of bulldozer 1. Figure 3 This is a schematic diagram of the power transmission system of bulldozer 1.

[0027] like Figure 1 As shown, the bulldozer 1 includes: left and right travel devices 4L and 4R, which include left and right sprockets 2L and 2R and left and right tracks 3L and 3R; a blade 5, which is located at the front of the vehicle; and a soil loosening device 6, which is located at the rear of the vehicle.

[0028] The bulldozer 1 is capable of performing operations such as bulldozing based on the blade 5, and crushing and excavation based on the loosening device 6.

[0029] like Figure 2 as well as Figure 3 As shown, the bulldozer 1 has an engine 10, an engine power transmission unit 20, left and right planetary gear mechanisms 30L and 30R, left and right steering clutches 40L and 40R, left and right steering brakes 50L and 50R, left and right output shafts 60L and 60R, a steering motor 80, a motor power transmission unit 90, and a controller 100.

[0030] [Engine Power Transmission Unit]

[0031] The engine power transmission unit 20 transmits power from the engine 10 to the left and right planetary gear mechanisms 30L and 30R. The engine power transmission unit 20 includes a power extraction device (power output device) 21, a torque converter 22, a transmission 23, a pinion 24, a bevel gear 25, and an input shaft 26.

[0032] The power take-off device 21 transmits power from the engine 10 to the torque converter 22. The torque converter 22 transmits the power from the engine 10 from the power take-off device 21 to the transmission 23 via fluid. The transmission 23 has multiple speed-stage clutches for changing the rotational power transmitted from the torque converter 22 and a directional clutch for switching between forward and reverse. The transmission 23 is connected to a pinion 24. Power from the transmission 23 is transmitted to the input shaft 26 via the pinion 24 and bevel gears 25. The input shaft 26 extends in a left-right direction. The axial direction of the input shaft 26 is synonymous with the left-right direction of the bulldozer 1.

[0033] Planetary gear mechanism

[0034] The left and right planetary gear mechanisms 30L and 30R are configured between the input shaft 26 and the left and right output shafts 60L and 60R. The left and right planetary gear mechanisms 30L and 30R have left and right ring gears 31L and 31R, left and right planetary gears 32L and 32R, left and right sun gears 33L and 33R, and left and right planet carriers 34L and 34R.

[0035] Left and right ring gears 31L and 31R are connected to the input shaft 26. Left and right planetary gears 32L and 32R are arranged radially perpendicular to the axial direction of the input shaft 26 and inside the left and right ring gears 31L and 31R. The left and right planetary gears 32L and 32R mesh with the left and right ring gears 31L and 31R and the left and right sun gears 33L and 33R. The left and right sun gears 33L and 33R are rotatably mounted relative to the input shaft 26. The left and right sun gears 33L and 33R are arranged radially inside the left and right planetary gears 32L and 32R. The left and right sun gears 33L and 33R are connected to the left and right steering clutches 40L and 40R. The left and right sun gears 33L and 33R can be disengaged or engaged with the motor power transmission unit 90 (specifically, the left and right clutch gears 91L and 91R described later) via the left and right steering clutches 40L and 40R. The left and right planetary carriers 34L and 34R are connected to the left and right planetary gears 32L and 32R and the left and right output shafts 60L and 60R.

[0036] [Steering clutch]

[0037] Left and right steering clutches 40L and 40R are disposed between the left and right planetary gear mechanisms 30L and 30R and the motor power transmission unit 90. The left and right steering clutches 40L and 40R disengage or engage the left and right sun gears 33L and 33R of the left and right planetary gear mechanisms 30L and 30R with the left and right clutch gears 91L and 91R of the motor power transmission unit 90.

[0038] The left and right steering clutches 40L and 40R are driven by the supply of working oil. The left and right steering clutches 40L and 40R are wet multi-plate clutches capable of engagement and disengagement. In this embodiment, the left and right steering clutches 40L and 40R are positive hydraulic clutches. The left and right steering clutches 40L and 40R are disengaged when no working oil is supplied, partially engaged when the hydraulic pressure of the supplied working oil is less than a predetermined value, and fully engaged when the hydraulic pressure of the supplied working oil is above the predetermined value.

[0039] The hydraulic pressure of the working oil supplied to the left and right steering clutches 40L and 40R is controlled by the left and right clutch control valves 27L and 27R. The left and right clutch control valves 27L and 27R are driven according to the clutch hydraulic pressure command input from the controller 100.

[0040] The left and right steering clutches 40L and 40R are switched by the left and right planetary gear mechanisms 30L and 30R, which transmit and disconnect the rotational power from the input shaft 26 to the left and right output shafts 60L and 60R.

[0041] Specifically, when the left steering clutch 40L is engaged, the rotation of the input shaft 26 is transmitted to the left output shaft 60L via the left ring gear 31L, the left planetary gear 32L, and the left planet carrier 34L. Conversely, when the left steering clutch 40L is disengaged, the left sun gear 33L becomes free-rotating, cutting off the transmission of rotational power from the input shaft 26 to the left output shaft 60L. Similarly, the right steering clutch 40R switches the transmission and disengagement of rotational power from the input shaft 26 to the right output shaft 60R depending on its engagement and disengagement.

[0042] Here, the left and right steering clutches 40L and 40R can rotate around the input shaft 26. The left and right steering clutches 40L and 40R rotate in opposite directions to each other by the rotational power from the steering motor 80 transmitted via the motor power transmission unit 90.

[0043] For example, when the left and right steering clutches 40L and 40R are engaged, when the left steering clutch 40L rotates forward and the right steering clutch 40R rotates in reverse, the speed of the left output shaft 60L becomes higher than the speed of the right output shaft 60R, and the bulldozer 1 turns to the right at differential speed.

[0044] In this manual, differential steering refers to the process of creating a speed difference between the left and right output shafts 60L and 60R, which rotate in the same direction, to move forward or backward in an arc with a relatively large turning radius.

[0045] Furthermore, with the left steering clutch 40L engaged and the right steering clutch 40R disengaged, when the left steering clutch 40L rotates forward, the rotation of the right output shaft 60R stops, and the left output shaft 60L rotates, causing the bulldozer 1 to turn to the right in place. However, when the bulldozer 1 is turning to the right in place, as described later, the right steering brake 50R brakes the right output shaft 60R.

[0046] In this specification, turning in place means turning around with the track on the other side as the axis by rotating one of the left and right output shafts 60L and 60R and bringing the other side to a substantial or complete stop.

[0047] like Figure 2 As shown, the right-turn clutch 40R has multiple clutch discs 41, multiple clutch plates 42, and a clutch piston 43.

[0048] Each clutch disc 41 is mounted on the right clutch gear 91R. Each clutch plate 42 is fixed to the right sun gear 33R. The clutch discs 41 and clutch plates 42 are alternately arranged in the axial direction.

[0049] When the clutch piston 43 moves to the right with the supply of working oil, the clutch discs 41 and 42 are pressed together, and the right steering clutch 40R engages. As a result, the right sun gear 33R of the right planetary gear mechanism 30R engages with the right clutch gear 91R of the motor power transmission unit 90.

[0050] On the other hand, when the clutch piston 43 moves to the left along with the discharge of working oil, each clutch plate 41 and each clutch disc 42 disengages, and the right steering clutch 40R is disengaged. As a result, the right sun gear 33R of the right planetary gear mechanism 30R is separated from the right clutch gear 91R of the motor power transmission unit 90.

[0051] It should be noted that the left-turn clutch 40L has the same structure as the right-turn clutch 40R.

[0052] [Steering brake]

[0053] The left and right steering brakes 50L and 50R are driven by the supply of hydraulic fluid. The left and right steering brakes 50L and 50R are composed of wet multi-plate clutches capable of engagement and disengagement. In this embodiment, the left and right steering brakes 50L and 50R are negative-type hydraulic brakes. The left and right steering brakes 50L and 50R are fully engaged when no hydraulic fluid is supplied, partially engaged when the hydraulic pressure of the supplied hydraulic fluid is less than a specified value, and disengaged when the hydraulic pressure of the supplied hydraulic fluid is above the specified value. When the left and right steering brakes 50L and 50R are engaged (fully or partially engaged), braking force is generated in the left and right steering brakes 50L and 50R.

[0054] The hydraulic pressure supplying the working oil to the left and right steering brakes 50L and 50R is controlled by the left and right brake control valves 28L and 28R. The left and right brake control valves 28L and 28R are driven according to the brake hydraulic pressure command input from the controller 100.

[0055] The left and right steering brakes 50L and 50R brake the rotation of the left and right output shafts 60L and 60R.

[0056] Specifically, when the left turn brake 50L is engaged, the rotation of the left output shaft 60L is braked, thereby reducing the rotation of the left sprocket 2L. On the other hand, when the right turn brake 50R is engaged, the rotation of the right output shaft 60R is braked, thereby reducing the rotation of the right sprocket 2R.

[0057] like Figure 2 As shown, the right turn brake 50R has a rotating component 51, a brake housing 52, multiple fixed plates 53, multiple brake discs 54, and a brake piston 55.

[0058] The rotating component 51 is fixed to the right output shaft 60R and rotates together with the right output shaft 60R. The brake housing 52 is fixed relative to the rotating component 51. Each fixing plate 53 is mounted on the brake housing 52. Each brake disc 54 is fixed to the rotating component 51. The fixing plates 53 and the brake discs 54 are alternately arranged in the axial direction.

[0059] When the brake piston 55 moves to the left as the working fluid is filled, the retaining pads 53 separate from the brake discs 54, and the right turn brake 50R is disengaged. On the other hand, when the brake piston 55 moves to the right as the working fluid is discharged, the retaining pads 53 and the brake discs 54 are pressed together, thereby generating braking force in the right turn brake 50R.

[0060] It should be noted that the left turn brake 50L has the same structure as the right turn brake 50R.

[0061] [Steering Motor]

[0062] The steering motor 80 is driven by the engine 10. The steering motor 80 rotates in either a forward or reverse direction. The direction and speed of rotation of the steering motor 80 are controlled by the controller 100. The speed of the steering motor 80 varies from 0% to 100% (maximum value) according to the power transmitted from the engine 10.

[0063] The rotational power of the steering motor 80 is transmitted to the left and right steering clutches 40L and 40R via the motor power transmission unit 90. The steering motor 80 rotates the left and right steering clutches 40L and 40R by creating a speed difference between the left and right output shafts 60L and 60R. For example, when the bulldozer 1 is making a differential right turn, when the steering motor 80 reverses the left and right steering clutches 40L and 40R, the speed of the left output shaft 60L becomes higher than the speed of the right output shaft 60R. Conversely, when the bulldozer 1 is making a stationary right turn, the steering motor 80 reverses the left and right steering clutches 40L and 40R, but because the right steering clutch 40R is disengaged and the right steering brake 50R is engaged, the right output shaft 60R does not rotate, and only the left output shaft 60L rotates.

[0064] [Electric motor power transmission section]

[0065] The motor power transmission unit 90 is disposed between the steering motor 80 and the left and right steering clutches 40L and 40R. The motor power transmission unit 90 transmits the rotational power of the steering motor 80 to the left and right steering clutches 40L and 40R.

[0066] The motor power transmission unit 90 includes left and right clutch gears 91L and 91R, a first transmission gear 92, a countershaft 93, a second transmission gear 94, an idler gear 95, and a pinion 96.

[0067] The left and right clutch gears 91L and 91R can disengage or engage with the left and right sun gears 33L and 33R via the left and right steering clutches 40L and 40R. The left and right clutch gears 91L and 91R can rotate about the axis of the input shaft 26. The left clutch gear 91L meshes with the idler gear 95. The right clutch gear 91R is connected to the idler gear 95 via the first transmission gear 92, the countershaft 93, and the second transmission gear 94. When the steering motor 80 rotates, the left and right clutch gears 91L and 91R rotate in opposite directions.

[0068] The idler gear 95 meshes with the left clutch gear 91L, the second transmission gear 94, and the pinion 96. The idler gear 95 is capable of rotating about the axis of the input shaft 26.

[0069] Pinion 96 meshes with idler gear 95. Pinion 96 is capable of rotating about pinion shaft 96a. Pinion 96 rotates by the rotational power of steering motor 80 transmitted via pinion shaft 96a.

[0070] [Controller]

[0071] In order to move the bulldozer 1, the controller 100 controls the speed of the engine 10 and the speed-stage clutch and directional clutch of the transmission 23.

[0072] The controller 100 controls the left and right steering clutches 40L and 40R, the left and right steering brakes 50L and 50R, and the steering motor 80 to enable the bulldozer 1 to travel in one of the following modes: "straight driving mode", "differential steering mode" and "stationary steering mode".

[0073] The controller 100 is connected to a steering lever 35 for steering operations of the bulldozer 1. The steering lever 35 can be operated in the left steering direction P2 and the right steering direction P3 respectively, with the neutral position P1 as a reference.

[0074] The controller 100 controls the bulldozer 1 to travel in one of the following modes: "straight driving mode", "differential steering mode" and "stationary steering mode" according to the operating direction and amount of the steering lever 35.

[0075] Figure 4 This is a diagram illustrating a control example of a bulldozer 1 based on controller 100.

[0076] When the steering lever 35 is operated to a value of less than or equal to a first predetermined value TH1, the controller 100 causes the bulldozer 1 to travel straight in straight mode. When the steering lever 35 is operated to a value greater than the first predetermined value TH1 and less than the second predetermined value TH2, the controller 100 causes the bulldozer 1 to steer in differential steering mode. When the steering lever 35 is operated to a value greater than or equal to the second predetermined value TH1, the controller 100 causes the bulldozer 2 to steer in stationary steering mode.

[0077] The second specified quantity TH2 is greater than the first specified quantity TH1. The first and second specified quantities TH1 and TH2 can be set to desired values. The first specified quantity TH1 can be "0".

[0078] Straight-through mode

[0079] In straight-line mode, controller 100 controls the control valves 27L and 27R of the left and right clutches to fully engage the left and right steering clutches 40L and 40R.

[0080] In straight driving mode, the controller 100 controls the left and right braking control valves 28L and 28R to disconnect the left and right steering brakes 50L and 50R.

[0081] In straight-line mode, controller 100 stops steering motor 80.

[0082] Differential steering mode

[0083] In differential steering mode, controller 100 controls the control valves 27L and 27R of the left and right clutches to engage the left and right steering clutches 40L and 40R (typically fully engaged).

[0084] In differential steering mode, controller 100 controls the left and right brake control valves 28L and 28R to disconnect the left and right steering brakes 50L and 50R.

[0085] In differential steering mode, the controller 100 adjusts the inner output shaft 60 in response to the increase in the amount of steering lever 35 operation. IN The rotational speed is 60 times that of the outer output shaft. OUT The steering motor 80 is driven at a low speed.

[0086] Inner output shaft 60 IN This refers to the output shaft among the left and right output shafts 60L and 60R that corresponds to the operating direction (i.e., the steering direction) of the steering lever 35. The outer output shaft 60... OUT It is the output shaft of the left and right output shafts 60L and 60R that is opposite to the operating direction of the steering rod 35.

[0087] The controller 100 increases the speed of the steering motor 80 as the amount of steering lever 35 is increased. For example, the controller 100 can gradually increase the speed of the steering motor 80 in proportion to the amount of steering lever 35 operation, or it can increase the speed of the steering motor 80 in stages according to the amount of steering lever 35 operation.

[0088] When the steering lever 35 is operated at the second specified amount TH2, the speed of the steering motor 80 is not particularly limited as long as it is high enough, but it is preferably 90% or more, more preferably 95% or more, and particularly preferably 100% (maximum value).

[0089] •Stationary turning mode

[0090] In stationary steering mode, controller 100 controls the control valves 27L and 27R of the left and right clutches, activating the inner steering clutch 40. IN Disengage the outer steering clutch 40. OUT Joining (typically full joining).

[0091] Inner steering clutch 40 IN This refers to the steering clutch in the left / right steering clutches 40L and 40R that corresponds to the operating direction of the steering lever 35. The outer steering clutch 40... OUT It is the steering clutch in the left and right steering clutches 40L and 40R that operates in the opposite direction to the steering lever 35.

[0092] In stationary steering mode, controller 100 controls the left and right braking control valves 28L and 28R, activating the inner steering brake 50. IN Braking, causing the outer steering brake to engage at 50 degrees. OUT disconnect.

[0093] Inner steering brake 50 INIt refers to the steering brake in the left and right steering brakes 50L and 50R that corresponds to the operating direction of the steering lever 35. The outer steering brake 50... OUT It is the steering brake in the left and right steering brakes 50L and 50R that operates in the opposite direction to the steering lever 35.

[0094] In stationary steering mode, the controller 100 maintains the rotational speed of the steering motor 80 at the same level as in differential steering mode. There is no particular limitation on the rotational speed of the steering motor 80 as long as it is sufficiently high, but it is preferably 90% or higher, more preferably 95% or higher, and particularly preferably 100%.

[0095] • Switching from stationary steering mode to straight driving mode or differential steering mode

[0096] When the controller 100 switches from stationary steering mode to straight-line mode or differential steering mode, it engages the inner steering clutch 40. IN The inner steering brake 50 is switched from the disengaged state to the engaged state. IN The system transitions from the braking state to the off state, and reduces the speed of the steering motor 80.

[0097] When the controller 100 immediately switches from stationary steering mode to straight-ahead mode, it stops the steering motor 80 (speed = 0%). When the controller 100 switches from stationary steering mode to differential steering mode, it reduces the speed of the steering motor 80 to the speed corresponding to the amount of operation of the steering lever 35 (0% < speed < 100%).

[0098] Figure 5 This is a diagram illustrating an example of the state of bulldozer 1 when it immediately switches from stationary turning mode to straight-line mode.

[0099] Figure 5 Indicates the control valve 27 for the inward clutch. IN Output clutch hydraulic command, inside steering clutch 40 IN The actual internal hydraulic pressure, the steering motor speed of 80, and the inner steering clutch speed of 40 IN The circumferential speed and the inner steering clutch 40 IN The heat loads generated vary over time.

[0100] Control valve 27 for inner clutch IN It refers to the control valves 27L and 27R for the left and right clutches, specifically the inner steering clutch 40. IN The corresponding clutch control valve. Inner steering clutch 40. IN The circumferential speed of the inner steering clutch is 40. IN The inner sun gear 33, which is idle due to the rotational power from the input shaft 26, is in contrast to this.IN The relative rotational speed.

[0101] exist Figure 5 In the middle, regarding the steering motor speed of 80 and the inner steering clutch speed of 40... IN The circumferential speed and thermal load are illustrated in the figures for both the embodiment and the comparative example. The embodiment involves the inner steering clutch 40. IN The case where the steering motor 80 speed decreases after initial engagement. A comparative example is the inner steering clutch 40. IN The steering motor 80 speed is reduced before the initial engagement.

[0102] (A) Controls related to comparative examples

[0103] Reference Figure 5 The controls related to the comparative examples are explained.

[0104] The steering motor speed of 80 starts to move inwards, controlled by the clutch control valve 27. IN The moment t0 when the hydraulic command to output the clutch is reduced to 0%. Therefore, the inner steering clutch 40 IN The circumferential speed is faster after time t0 than when turning in place.

[0105] Inside steering clutch 40 IN In the process, working oil is gradually added after time t0, and the filling of working oil is completed at time t1 (an example of "first time"). Then, the inner steering clutch 40... IN Partial engagement begins at time t1, and full engagement occurs at time t2 (an example of "second time"). Therefore, the inner steering clutch 40... IN The circumferential velocity gradually decreases from time t1 to time t2, and becomes 0 after time t2.

[0106] Inside steering clutch 40 IN The heat load generated in the middle is diverted from the inside to the clutch 40. IN The engagement time t1 begins to gradually increase, reaching its highest value at time t3, after which the inner steering clutch rotates at 40 degrees. IN The moment of complete engagement, t2, becomes 0.

[0107] Thus, in the comparative example, the inner steering clutch 40 IN Before the moment t1 when partial engagement begins, the steering motor 80's speed decreases, therefore the inner steering clutch 40 at moment t1... IN The high circumferential speed results in a 40° turn on the inner steering clutch. IN The heat load generated in the process increases.

[0108] (B) Controls related to the implementation plan

[0109] Reference Figure 5 The controls related to the embodiments are described.

[0110] The steering motor speed of 80 starts to move inwards, controlled by the clutch control valve 27. IN The moment t0 after which the hydraulic command to the clutch is output is also maintained. Therefore, the inner steering clutch 40 IN The circumferential velocity after time t0 is the same as during the stationary turning.

[0111] Inside steering clutch 40 IN During the process, working oil is gradually added after time t0, and the filling of working oil is completed at time t1. Then, the inner steering clutch 40... IN The clutch begins to partially engage at time t1 and fully engages at time t2. Therefore, the inner steering clutch 40... IN The circumferential velocity gradually decreases from time t1 to time t2, and becomes 0 after time t2.

[0112] Inside steering clutch 40 IN The heat load generated in the middle is diverted from the inside to the clutch 40. IN The engagement time t1 begins to gradually increase, reaching its highest value at time t3, after which the inner steering clutch 40... IN The moment of complete engagement, t2, becomes 0.

[0113] Thus, in this embodiment, the rotational speed of the steering motor 80 is maintained until the inner steering clutch 40. IN The moment of initial partial engagement is t1, therefore the inner steering clutch at time t1 is 40. IN The circumferential speed is slower than the comparative example mentioned above, which results in the ability to suppress the inner steering clutch 40. IN The heat load generated in the process.

[0114] It should be noted that, in this embodiment, if the inner steering clutch is exceeded by 40... IN At the moment t1 when partial engagement begins, the speed of the steering motor 80 immediately begins to decrease, but this is not the only time this will happen. Even on the inner steering clutch 40... IN Maintaining the speed of the steering motor 80 after the initial engagement time t1 also achieves a thermal load suppression effect. Therefore, the controller 100 only needs to maintain the speed of the steering motor 80 after time t1.

[0115] It should be noted that, in this embodiment, the steering clutch 40 is located exactly on the inner side. IN At the moment of full engagement t2, the steering motor 80 stops, but is not limited to this. Even on the inside steering clutch 40... INBy stopping the steering motor 80 before the moment of full engagement t2, the system can quickly transition to straight-line mode. Therefore, the controller 100 only needs to stop the steering motor 80 before moment t2.

[0116] Additionally, in this embodiment, the inner steering clutch 40 IN The steering motor 80 stops after time t3, when the heat load generated in the system reaches its highest value. Therefore, compared to stopping the steering motor 80 before time t3, the pressure on the inner steering clutch 40 can be reduced. IN The highest value of heat load generated in the process.

[0117] Above, refer to Figure 5 The speed control of the steering motor 80 is explained when switching immediately from stationary steering mode to straight driving mode. However, the speed control of the steering motor 80 is also performed when switching from stationary steering mode to differential steering mode.

[0118] (Modifications of the implementation method)

[0119] This invention is not limited to the above embodiments, and various modifications or alterations can be made without departing from the scope of this invention.

[0120] (Variation Example 1)

[0121] In the above embodiments, the controller 100 is configured to switch from differential steering mode to stationary steering mode and from stationary steering mode to differential steering mode based on the amount of operation of the steering lever 35, but is not limited thereto. The controller 100 may also switch from differential steering mode to stationary steering mode if the amount of operation of the steering lever 35 is greater than a first predetermined amount TH1 and a stationary steering instruction is received from the operator. Furthermore, the controller 100 may also switch from stationary steering mode to differential steering mode if a stationary steering instruction is no longer received from the operator in stationary steering mode.

[0122] Here, Figure 6 This is a schematic system structure diagram of the power transmission system of the bulldozer 1a in this modified example. Except for the stationary steering button 36, the bulldozer 1a has the same structure as the bulldozer 1 in the above-described embodiment.

[0123] The stationary turn button 36 is connected to the controller 100. The stationary turn button 36 receives stationary turn instructions from the operator. When the operator presses the stationary turn button 36, the stationary turn button 36 sends the stationary turn instruction to the controller 100. The stationary turn button 36 can send the stationary turn instruction to the controller 100 while it is being pressed by the operator, or it can continuously send the stationary turn instruction to the controller 100 until the operator presses it again.

[0124] When the amount of operation of the steering lever 35 is less than or equal to a first predetermined amount TH1, the controller 100 sets the driving mode of the bulldozer 1 to straight-line mode, as described in the above embodiment.

[0125] When the amount of operation of the steering lever 35 is greater than the first predetermined amount TH1 and no stationary steering instruction is received, the controller 100 sets the driving mode of the bulldozer 1 to differential steering mode. The control of the controller 100 in differential steering mode is as described in the above embodiment.

[0126] When the amount of operation of the steering lever 35 is greater than the first predetermined amount TH1 and a stationary steering instruction is received, the controller 100 sets the driving mode of the bulldozer 1 to the stationary steering mode. The control of the controller 100 in the stationary steering mode is as described in the above embodiment.

[0127] The controller 100 controls the switching from stationary steering mode to differential steering mode as described in the above embodiment.

[0128] (Variation Example 2)

[0129] In the above embodiment, the left and right steering clutches 40L and 40R are set as positive hydraulic clutches, but they can also be negative hydraulic clutches.

[0130] (Variation Example 3)

[0131] In the above embodiment, the left and right steering brakes 50L and 50R are set as negative hydraulic brakes, but they can also be positive hydraulic brakes.

[0132] (Variation Example 4)

[0133] In the above embodiment, the left and right output shafts 60L and 60R are connected to the left and right sprockets 2L and 2R. However, a left and right final reduction device can also be sandwiched between the left and right output shafts 60L and 60R and the left and right sprockets 2L and 2R.

[0134] (Variation Example 5)

[0135] In the above embodiment, the speed control of the steering motor 80 is set to be performed in two cases: when switching immediately from stationary steering mode to straight driving mode and when turning from stationary steering mode to differential steering mode. However, the speed control of the steering motor 80 may be performed only in one of the cases.

[0136] Explanation of reference numerals in the attached figures

[0137] 1. Bulldozer

[0138] 10 Engines

[0139] 20 Engine power transmission unit

[0140] 26 Input axes

[0141] 30L and 30R planetary gear mechanisms

[0142] 31L and 31R left and right gear rings

[0143] 32L and 32R planetary gears (left and right)

[0144] 33L and 33R sun gears

[0145] Planetary carriers around 34L and 34R

[0146] 40L, 40R left and right steering clutch

[0147] 50L, 50R left and right steering brakes

[0148] 60L, 60R output shaft

[0149] 80 Steering Motor

[0150] 90 Electric motor power transmission section

[0151] 91L and 91R left and right clutch gears

[0152] 92 First transmission gear

[0153] 93 Sub-shaft

[0154] 94 Second transmission gear

[0155] 95 Idler Gear

[0156] 96 small gears

[0157] 98 Fixed components

[0158] 99 Steering Motor

[0159] 100 Controller

Claims

1. A tracked engineering machine, characterized in that, have: The left and right planetary gear mechanism is configured between the input shaft and the left and right output shafts; Left and right steering clutches are rotatable about the input shaft to switch and disconnect the transmission of rotational power from the input shaft to the left and right output shafts via the left and right planetary gear mechanisms. Left and right steering brakes, which brake the left and right output shafts; A steering motor that rotates the left and right steering clutches in such a way as to create a speed difference between the left and right output shafts; The controller controls the left and right steering clutches, the left and right steering brakes, and the steering motor to enable the tracked construction machinery to steer in one of the following modes: straight-line mode, differential steering mode, and stationary steering mode. In the straight-ahead mode, the controller engages the left and right steering clutches, disengages the left and right steering brakes, and stops the steering motor. In the differential steering mode, the controller engages the left and right steering clutches, disengages the left and right steering brakes, and drives the steering motor. In the stationary steering mode, the controller disengages the inner steering clutch corresponding to the steering direction among the left and right steering clutches, engages the inner steering brake corresponding to the steering direction among the left and right steering brakes, and drives the steering motor. When the controller switches from the stationary steering mode to the straight-ahead mode or the differential steering mode, it maintains the speed of the steering motor until after the first moment when the inner steering clutch begins to partially engage.

2. The tracked engineering machinery as described in claim 1, wherein, When the controller switches from the stationary steering mode to the straight-ahead mode or the differential steering mode, it stops the steering motor before the second moment when the inner steering clutch is fully engaged.

3. The tracked engineering machinery as described in claim 1 or 2, wherein, The left and right planetary gear mechanisms respectively have: A gear ring, which is connected to the input shaft; The sun gear is rotatably mounted on the input shaft and connected to the steering clutch; A planetary gear, which is disposed between the ring gear and the sun gear; Planetary carrier, which is connected to the planetary gears and the output shaft.

4. The tracked engineering machinery as described in claim 3, wherein, have: The left and right clutch gears are capable of disengaging from or engaging with the sun gears of the left and right planetary gear mechanisms via the left and right steering clutches, and rotating in opposite directions to each other; An idler gear transmits the rotational power of the steering motor to the left and right clutch gears.

Images