JP2024011348A - Transmission for traveling vehicle - Google Patents

Abstract

To provide a traveling vehicle with an excellent energy saving property, capable of using a continuously variable transmission both for straight advance and revolving to reduce cost, and capable of reducing capacities of various kinds of devices for supplying hydraulic oil.SOLUTION: In a transmission 1 of a traveling vehicle comprising a common HST 11 for shifting and revolving, a revolving gear mechanism 18 has a first multi-disc clutch 93 and a second multi-disc clutch 96 that can freely switch rotation of a second element in a forward or reverse direction. The first and second multi-disc clutches 93, 96 disengage both the multi-disc clutches 93, 96 when an indicator is in a straight advance operation state with respect to a steering handle 170 of the vehicle; in a steering state, alternatively selects one of the multi-disc clutches 93, 96 as one to be engaged according to a steering direction; and interlocks the multi-disc clutches 93, 96 to increase a degree of engagement as an amount of steering increases.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transmission for a vehicle.

BACKGROUND ART Crawler vehicles such as combine harvesters or tillage tractors that continuously cut and thresh grain culms in a field have been known. The transmission for the above-mentioned crawler vehicle uses an engine as a drive source to drive the left and right crawlers in the same direction at the same speed, and a hydraulic continuously variable transmission that drives the left and right crawlers at different speeds and in opposite directions. It is linked to the left and right crawlers through a hydraulic continuously variable transmission system for possible turning and a planetary gear mechanism, and each transmission is controlled by the steering handle and shift lever operation, providing driving force to both the left and right crawlers. There is a known technology that allows the vehicle to move forward and backward and turn while transmitting the following information.

Japanese Patent Application Publication No. 2001-277898

However, when continuously variable transmissions are provided separately for driving and turning, the cost may increase. In addition, the capacity of the charge pump that supplies hydraulic oil to each transmission, the required amount of hydraulic oil, and the capacity of two coolers to cool the hydraulic oil were also required, making each device larger. . Furthermore, engine power was required to drive each transmission.

Therefore, the present invention has been made in view of the above problems, and by integrating the continuously variable transmission into one, it is possible to suppress costs and reduce the capacity of various devices that supply hydraulic oil. The purpose is to provide a transmission for crawler vehicles that is highly energy-saving.

The problem to be solved by the present invention is as described above, and next, means for solving this problem will be explained.

That is, the transmission for a crawler vehicle disclosed in the present application includes a common continuously variable transmission for shifting and turning, and includes a linear gear mechanism and a swing gear mechanism connected in parallel to the continuously variable transmission. a first element that receives an output from the linear gear mechanism; a second element that receives an output from the swing gear mechanism; and a left-right drive unit that combines the power of the first element with the power of the second element. In the transmission for a traveling vehicle, the transmission includes a planetary gear mechanism including a third element that outputs output to a wheel; The first and second multi-disc clutches disengage both multi-disc clutches when the indicator is in a straight-ahead operation state, and disengage both multi-disc clutches when the indicator is in a straight-ahead operating state in response to a steering indicator of the vehicle. According to the steering direction, one of the multi-disc clutches is selected to be engaged, and as the amount of steering increases, the degree of engagement of the multi-disc clutch increases.

In the transmission for a crawler vehicle disclosed in the present application, the second element is fixed to the lower power transmission side of the first and second multi-disc clutches so as not to rotate when both multi-disc clutches are disengaged. Preferably, a brake is provided.

According to the present invention, by using only one continuously variable transmission, it is possible to reduce costs, reduce the capacity of various devices that supply hydraulic oil, and furthermore, engine power is provided by only one continuously variable transmission. It is possible to provide a running vehicle with excellent energy saving performance.

FIG. 1 is a power transmission diagram showing a transmission for a crawler vehicle according to an embodiment of the present invention. FIG. 3 is a schematic front view showing the transmission. FIG. 3 is a side sectional view showing a traveling sub-transmission gear mechanism of the transmission. FIG. 3 is a side cross-sectional view showing the turning gear mechanism of the transmission. Also a hydraulic circuit diagram of the transmission. Similarly, it is a graph diagram showing the relationship between the amount of steering of the steering wheel and the degree of engagement of the multi-disc clutch.

A traveling vehicle transmission mounted on a crawler vehicle according to an embodiment of the present invention will be described. As shown in FIGS. 1 and 2, the transmission 1 includes a hydraulic continuously variable transmission (hereinafter referred to as HST) 11 that uses power from an engine for both straight-line travel and turning. In this embodiment, the continuously variable transmission is a hydraulic type, but various types of continuously variable transmission such as an electric type and a mechanical friction type may be used.

As shown in FIGS. 1 and 2, the transmission 1 includes a linear gear mechanism 17, a swing gear mechanism 18, and a single hydraulic continuously variable transmission (HST) 11 that powers both mechanisms 17 and 18. Inside the mission case 16, there is a linear gear mechanism 17 that transmits the power of the HST 11, a swing gear mechanism 18 that transmits the power of the HST 11, and a system that combines the power from the linear gear mechanism 17 and the power from the swing gear mechanism. It accommodates planetary gear mechanisms 13L and 13R that distribute and output power to left and right traveling crawlers 15L and 15R.

The planetary gear mechanisms 13L and 13R have three power transmission elements, and in this embodiment, the first element is a sun gear 81 (described later), the second element is an internal gear 82, and the third element is a carrier 83 and a planetary gear 84. There is.

As shown in FIG. 1, the variable speed pump 31 and variable speed motor 32 of the HST 11 are components that constitute a hydraulic continuously variable transmission. Power from the engine 10, which is a driving source, is transmitted to a variable speed pump 31 having a variable speed pump shaft 31a. The variable speed motor 32 having the variable speed pump 31 and the variable speed motor shaft 32a is a pair of pump and motor that are hydraulically connected, and controls the output of the variable speed motor 32 by changing the swash plate angle of the variable speed pump 31. As shown in FIG. 2, the HST 11 is mounted on one side of the transmission case 16 in the left and right direction of the vehicle.

As shown in FIGS. 2 and 3, the transmission 1 is housed within a transmission case 16. The linear gear mechanism 17 is arranged between a sub-transmission 51 that receives power from the HST 11 and outputs it to the sun gear 81, which is the first element of the planetary gear mechanisms 13L and 13R, and a second linear shaft 57 of the sub-transmission 51. and a parking brake 52.

The sub-transmission device 51 includes a first straight-travel shaft 54 provided with an input gear 53 that meshes with an output gear 32b provided on the speed-change motor shaft 32a of the speed-change motor 32, and a first straight-travel shaft 54 provided on the first straight-travel shaft 54. A second shaft 57 for straight movement is provided with an input gear mechanism 56 for shifting that selectively meshes with the output gear mechanism 55 for shifting.

The first shaft 54 for straight movement is a sub-transmission output shaft, and includes a transmission output gear mechanism 55 of the sub-transmission device 51 . The speed change output gear mechanism 55 is composed of a plurality of gears having different diameters. In the speed change output gear mechanism 55, a plurality of gears are fixed to the first straight shaft 54, and one gear is fitted to the first straight shaft 54 so as to be relatively rotatable.

Further, the second straight-travel shaft 57 is a sub-transmission input shaft, and includes a transmission input gear mechanism 56 of the sub-transmission device 51 . The speed change input gear mechanism 56 is composed of a plurality of gears having different diameters. In the transmission input gear mechanism 56, a plurality of gears are fitted to the second shaft 57 for straight movement so as to be relatively rotatable, and one gear is fixed to the first shaft 54 for straight movement.

In addition, the input gear mechanism 56 for speed change includes a first clutch 60A that can be engaged with two gears fixed to the first straight shaft 54, and can be selectively engaged with one gear. , it is possible to transmit the rotational power from the first straight-travel shaft 54 to the second straight-travel shaft 57 by changing the speed to low/medium speed. The first clutch 60A is interlocked with a sub-shift lever (not shown), and switching of the first clutch 60A is performed by operating the sub-shift lever.

In addition, the input gear mechanism 56 for speed change includes a second clutch 60B that can be engaged with one gear that is relatively rotatably fitted to the first shaft 54 for straight movement, and that can be selectively engaged with the gear. By doing so, it is possible to change the speed of the rotational power from the first straight shaft 54 at high speed and transmit it to the second straight shaft 57. The second clutch 60B is also interlocked with the auxiliary shift lever, and is mechanically operated so that the second clutch 60B is switched by operating the auxiliary shift lever in a direction different from the switching direction of the first clutch 60A. It is linked and linked.

A large-diameter gear 61 for output is fixed to the second straight shaft 57 so as not to be relatively rotatable. Large diameter gear 61 meshes with drive gear 63 of sun gear shaft 62 .

The left and right planetary gear mechanisms 13L and 13R include a sun gear 81 formed on the sun gear shaft 62, an internal gear 82 that is rotatably supported on the output shafts 19L and 19R, a carrier 83 that is fixed to the output shafts 19L and 19R, and a sun gear 81 that is formed on the sun gear shaft 62. 81 and an internal gear 82, and both ends of the sun gear shaft 62 are rotatably supported by the output shafts 19L and 19R via a carrier 83. Further, one end of the pinion shaft 85 is press-fitted into the carrier 83 and fixed thereto. A planetary gear 84 is freely rotatably supported on the pinion shaft 85.

The rotational power for linear movement from the first shaft 54 for linear movement is transmitted from the sun gear shaft 62 to the sun gears 81 of the left and right planetary gear mechanisms 13L and 13R. When an internal gear 82, which will be described later, is restrained from rotating, the rotation of the sun gear 81 is transmitted from the carrier 83 to the left and right crawlers 15L and 15R via the planetary gear 84. When the operator changes the direction and speed of the output rotation of the HST 11 using a main speed change lever (not shown), the left and right crawlers 15L and 15R are driven in a continuously variable speed direction (forward or backward).

On the other hand, as shown in FIGS. 1 and 4, the swing gear mechanism 18 includes a first shaft 92 for swing. The first turning shaft 92 includes a turning input gear 91 that meshes with the output gear 32b of the variable speed motor 32 of the HST 11 via the input gear 53.

A clutch housing 94c of a first multi-disc clutch 93 is fixed to the first turning shaft 92. Further, an output gear 101 that can be freely engaged and disengaged from a clutch housing 94c of a first multi-disc clutch 93 is loosely fitted and supported on the first turning shaft 92.

The first multi-disc clutch 93 is a wet multi-disc clutch that performs on/off transmission of power from the first turning shaft 92 that rotates in the normal direction to the gear 101 and changes the speed. The first multi-disc clutch 93 includes a plurality of overlapping shaft-side clutch plates and gear-side clutch plates that rotate in conjunction with the first turning shaft 92, and moves both clutch plates by advancing and retreating a hydraulic piston 94b. Power can be transmitted from the shaft 94 to the gear 101 by bringing them into close contact with each other from a separated state.

On the other hand, a clutch housing 97c of a second multi-disc clutch 96 is fixed to a second turning shaft 95 provided parallel to the first turning shaft 92, and both shafts 92 and 95 are formed on the outer periphery of each housing. They are interlocked and connected via gears 94a and 97a. Further, an output gear 102 that can be freely engaged and disengaged from a clutch housing 97c of a second multi-disc clutch 96 is loosely fitted and supported on the second turning shaft 95.

The second multi-disc clutch 96 is a wet-type multi-disc clutch that performs on/off transmission of power from the rotation of the second turning shaft 95 that rotates in the reverse direction to the gear 102 and changes the speed. The second multi-disc clutch 96 includes a plurality of overlapping shaft-side clutch plates and gear-side clutch plates that rotate in conjunction with the second turning shaft 95, and separates both clutch plates by advancing and retreating a hydraulic piston 97b. By bringing them into close contact with each other, power can be transmitted from the shaft 95 to the gear 102.

The gear 94a and the gear 97a have the same number of teeth, and the output gear 101 and the output gear 102 have the same number of teeth, and a common swing output gear 104 is meshed with both of the output gears 101 and 102. There is. As a result, the rotation output gear 104 has the same reduction ratio and the rotation direction when the second multi-disc clutch 96 is engaged is positive, and the rotation direction when the first multi-disc clutch 93 is engaged is positive. is configured so that it is reversed. Which of the first multi-disc clutch 93 and the second multi-disc clutch 96 is to be engaged is determined based on the steering direction when the switching operator operates the steering handle 170 in FIG. 5 . This detailed mechanism will be described later.

A torque-sensitive anti-swing brake 105 is provided on the third swing shaft 103 to which the swing output gear 104 is fixed. This brake 105 has the same mechanism and function as those described in Japanese Patent Application Laid-open No. 2001-225761, and includes a cam mechanism, a biasing spring, and a biasing spring, which are main parts (not shown). A brake plate is provided, and when the torque of the swing output gear 104 and the third swing shaft 103 is zero or less than the value equivalent to the biasing force of the biasing spring, the biasing spring brakes the brake disc. The output gear 106 is fixed so as not to rotate. When a torque equal to or greater than the biasing force of the biasing spring acts on the swing output gear 104, the cam mechanism releases the braking of the brake plate and the torque is output from the output gear 106, which is provided on the fourth swing shaft 110. The signal is transmitted to input gear 111.

An intermediate output gear 112 is fixed to the fourth turning shaft 110. The intermediate output gear 112 meshes with a gear 115 fixed to the fifth rotating shaft 114.

The fifth shaft for turning 114 is provided with fifth shaft output gears 118 and 119 for transmitting power to the internal gear 82, which is the second element of the left and right planetary gear mechanisms 13L and 13R. The fifth shaft side output gear 118 meshes with the outer gear 82b of the left internal gear 82 via the intermediate gear 120. Further, the fifth shaft side output gear 119 directly meshes with the outer gear 82b of the right internal gear 82.

The rotational power of the HST 11 when traveling straight is transferred straight through the planetary gear mechanisms 13L and 13R without any loss because the internal gears 82 and 82 on the left and right do not rotate and are fixed so that they cannot rotate by the rotation prevention brake 105. Can be used for driving.
When the first multi-disc clutch 93 or the second multi-disc clutch 96 is engaged during a turn and the fourth turning shaft 110 is released from the restraint by the anti-turn brake 105 and rotates, the rotational power of the HST 11 when traveling straight is The left and right internal gears 82 are driven at the same rotational speed, but in opposite directions.

Next, the hydraulic system will be explained using FIGS. 1 and 5.
As shown in FIGS. 1 and 5, the HST 11 is configured by connecting an axial piston type variable speed pump 31 and a motor through a closed circuit 142, and in this embodiment, the pump side swash plate 31b is a movable swash plate. Yes, and the motor side swash plate is a fixed swash plate.

As shown in FIG. 5, the HST 11 includes an auxiliary pump 141 driven by a pump shaft 31a, a closed circuit 142 that receives pressure oil supply from the auxiliary pump 141, and a relief valve 143 that sets the oil pressure supplied to the closed circuit 142. , one end of which is fluidly connected to the closed circuit 142 and allows pressure oil to flow in from the closed circuit 142 and a charge line 145 which is branched into first and second branch lines 145a and 145b at a branch point 144; , and check valves 146 inserted in the first and second branch lines 145a and 145b, respectively, to prevent reverse flow.

Further, as shown in FIG. 5, each of the first and second branch lines 145a and 145b has a high pressure relief valve 147 provided in parallel with the check valve 146. The high pressure relief valve 147 is connected to a branch line 145b connected to the other hydraulic oil line that constitutes the closed circuit 142, to transfer pressure oil from one hydraulic oil line when the pressure is abnormally high in one of the hydraulic oil lines that constitute the closed circuit 142. and relief to the other hydraulic oil line via the check valve 146.

Further, one of the first and second branch lines 145a and 145b includes a bypass line 150 that bypasses the check valve 146 inserted in the one branch line, and a throttle 150a inserted in the bypass line 150. It is provided.

The bypass line 150 and the throttle 150a are provided to ensure the HST neutral width while preventing deterioration of HST operating efficiency to the extent possible, and are preferably fluidly connected to the hydraulic oil line on the high pressure side when traveling in reverse. branch line 145b.

Further, as shown in FIG. 5, the HST 11 includes an electrically controlled hydraulic servo mechanism 160 that can be operated by receiving pressure oil from the auxiliary pump 141. As shown in FIG. 5, the hydraulic servo mechanism 160 includes a servo piston 161 configured to be able to reciprocate, and a connecting pin 162 that connects the servo piston 161 to the pump side swash plate 31b.
The connecting pin 162 connects the servo piston 161 and the pump side swash plate 31b so that the pump side swash plate 31b tilts in accordance with the movement of the servo piston 161.

The hydraulic servo mechanism 160 further includes a supply/discharge line 163 that is fluidly connected to each oil chamber of the servo piston 161, and a switching valve 165 and a solenoid valve 166 that switch the connection state with the drain line 164.

The aforementioned first and second multi-disc clutches 93 and 96 control the adhesion force of the clutch plates from a disengaged state to a fully engaged state using a steering handle 170, which is a manually operable steering instruction tool, as shown in FIG. The steering wheel is configured so that it can be changed steplessly according to the steering condition of the steering wheel.
Specifically, a mechanical linkage mechanism is provided that transmits the operating force of the steering handle 170 for moving straight, turning to the right, and turning to the left to the operating parts of the first multi-disc clutch 93 and the second multi-disc clutch 96, or as will be described later. The amount of steering of the steering handle 170 may be converted into an electrical signal using a potentiometer or the like, and the contact force of the clutch plate may be changed by converting the signal into hydraulic pressure according to the signal value. Note that the structure of the steering handle 170, which is a steering member, can take various configurations.

In this embodiment, the control device 171 controls the oil supply pressure to the first multi-disc clutch 93 or the second multi-disc clutch 96 separately so that the steering direction and turning radius according to the manual operation of the steering handle 170 can be obtained. The clutch plate is configured to adjust and control the adhesion force of the clutch plate.

The hydraulic oil supply line that receives pressurized oil from the auxiliary pump 141 is further provided with branch points 173a and 173b, and clutch hydraulic oil lines 174a and 174b that branch from the branch points 173a and 173b are connected to the first multi-disc clutch 93 and It is connected to the operating section (fueling port) of the second multi-disc clutch 96. In the middle of this line, pressure proportional valves 175a and 175b are provided to switch between inflow and stop of pressure oil from the hydraulic oil supply line.

For example, when engaging the first multi-disc clutch 93 by turning the steering handle 170 to the right, the pressure proportional valve 175a in the clutch hydraulic oil line 174a is energized and becomes open, and the first multi-disc clutch 93 Hydraulic oil is supplied to. Further, when the second multi-disc clutch 96 is operated by turning the steering handle 170 to the left, the pressure proportional valve 175b in the clutch hydraulic oil line 174b is energized and becomes open, and the second multi-disc clutch Hydraulic oil is supplied to 96.

A lubricating oil pressure setting relief valve 151 is interposed in the oil drain line of the relief valve 143, and a lubricating oil line 174c is provided from a branch point 173c on the primary side of the relief valve 151, and the end is connected to the multi-disc clutches 93 and 96 and the rotation prevention brake. 105 in parallel to each lubricating oil introduction port. Although not shown, the multi-disc clutches 93 and 96 and the anti-swing brake 105 have a lubricating oil supply structure for lubricated parts such as clutch plates and brake plates as usual. Reference numeral 100 in FIG. 4 indicates an oil passage block, which is fitted into the shaft end protrusions 92a and 95a of the first pivot shaft 92 and the second pivot shaft 95 for pivoting. A clutch hydraulic oil introduction port and a lubricating oil introducing port are opened in each of the shaft end protrusions 92a and 95a, and are connected to clutch hydraulic oil lines 174a and 174b and a lubricating oil line 174c via an oil passage block 100.

As shown in FIG. 6, when the steering handle 170 is operated to move straight, the control device 171 closes the pressure proportional valves 175a and 175b, stopping oil supply to the multi-disc clutches 93 and 96. , the hydraulic oil in the piston chambers of the multi-plate clutches 93 and 96 is drained into the tank. Therefore, the swing output gear 104 does not rotate, and the output gear 106 is fixed by the action of the swing prevention brake 105 described above. On the other hand, when the steering wheel 170 is turned to the right or left, the control device 171 quadratically increases the amount of power supplied to the pressure proportional valve 175a (or 175b) according to the amount of steering, and the first multi-disc clutch 93 The engagement hydraulic pressure of the (second multi-disc clutch 96) with respect to the hydraulic piston increases, and the rotation of the swing output gear 104 increases. Note that when the steering handle 170 is operated within the range of play, the rotational torque of the swing output gear 104 does not exceed a value corresponding to the setting bias of the swing prevention brake 105, so the fixed state of the swing output gear 104 is maintained. Incidentally, the rise of the engagement hydraulic pressure may be adjusted and controlled artificially so as to be slow or slow depending on the hardness or softness of the traveling road surface.

Next, power transmission by the transmission 1 will be explained using FIG. 1.
The transmission 1 receives the power output from the HST 11 as rotational power for straight travel and turning. The rotational power output from the variable speed motor shaft 32a of the HST 11 is transmitted to the input gear 53 that meshes with the output gear 32b, and then to the first straight shaft 54. The rotational power for straight travel outputted from the first shaft for straight travel 54 is changed in speed and transmitted to the second shaft for straight travel 57 via the sub-transmission device 51 . The sub-transmission device 51 changes the rotational speed by selecting the ratio of the gear diameters of the speed-changing output gear mechanism 55 and the speed-changing input gear mechanism 56 using a clutch 60.

The rotational power for linear movement output from the second shaft for linear movement 57 is transmitted to the input gear 63 that meshes with the large diameter gear 61, and then to the sun gear shaft 62. The linear rotational power output from the sun gear shaft 62 is distributed to the left and right and transmitted to the pair of planetary gear mechanisms 13L and 13R at the same rotational speed and in the same rotational direction.

On the other hand, the rotational power output from the variable speed motor shaft 32a of the HST 11 is transmitted to the swing gear mechanism 18. The output gear 32b, the input gear 53, and the swing input gear 91 are meshed in series, and the rotation of the output gear 32b is transmitted to the swing input gear 91.

The rotational power output to the first turning shaft 92 is transmitted as rotation in the forward rotation direction. The rotational power of the first turning shaft 92 is transmitted as rotational power in the reverse direction to the second turning shaft via the gear 94a and the gear 97a.

When it is desired to turn the vehicle clockwise, the first multi-plate clutch 93 is connected. By connecting the first multi-disc clutch 93, the rotational power of the first turning shaft 92 in the normal rotation direction is outputted to the third turning shaft 103 via the gear 101 and the turning output gear 104. At this time, as the amount of steering of the steering handle 170 increases, the engagement force (clutch plate contact force) of the first multi-disc clutch 93 is adjusted steplessly from a disengaged state to a fully engaged state. The rotational torque applied to the third turning shaft 103 can be varied steplessly.

Furthermore, when the vehicle is desired to turn counterclockwise, the second multi-disc clutch 96 is connected. By connecting the second multi-disc clutch 96, the rotational power of the second turning shaft 95 in the reverse direction is outputted to the third turning shaft 103 via the gear 102 and the turning output gear 104. At this time, as the amount of steering of the steering handle 170 increases, the engagement force (clutch plate contact force) of the second multi-disc clutch 96 is adjusted steplessly from a disengaged state to a fully engaged state. The rotational torque applied to the third turning shaft 103 can be varied steplessly.

Furthermore, since lubricating oil is always introduced into the clutch plates of multi-disc clutches 93 and 96, the heat generated by friction while changing the adhesion force of the clutch plates is absorbed by the lubricating oil flowing around the clutch plates. Since it is cooled down, burn-in is suppressed.

Here, when the torque applied to the third turning shaft 103 is less than the biasing force equivalent value of the anti-turning brake 105, the output gear 106 is fixed so as not to rotate. When the value equivalent to the urging force is exceeded, the torque of the third turning shaft 103 is transmitted to the output gear 106.

Power generated by the output gear 106 is transmitted to the fourth turning shaft 110 via the input gear 111.
The rotational power for turning output from the fourth shaft for turning 110 is distributed to the left and right. The rotational power for turning on the left side is transmitted to the fifth shaft side output gear 118, the intermediate gear 120, and the outer gear 82b of the ring gear 82. On the other hand, the rotational power for turning on the right side is directly transmitted to the fifth shaft side output gear 119 and the outer gear 82b of the internal gear 82 of the planetary gear mechanisms 13L and 13R on the right side.
Therefore, when the power of the variable speed motor shaft 32a of the HST 11 is output via the swing gear mechanism 18, the internal gears 82 and 82 of the pair of planetary gear mechanisms 13L and 13R are rotated at the same rotation speed, but at the same rotation speed. They are driven in opposite directions with respect to each other.

As a result, when traveling straight (forward or reverse), the output set by changing the swash plate angle of the HST 11 and the speed stage selected by the sub-transmission device 51 drives the sun gear shaft 62 of the planetary gear mechanisms 13L and 13R. , are transmitted to carriers 83, 83 via respective planetary gears 84, 84. At this time, since the output of the swing gear mechanism 18 is zero, the swing prevention brake 105 is activated to fix both internal gears 82, 82 unrotatably. As a result, when the planetary gears 84, 84 meshing with the fixed internal gears 82, 82 revolve while rotating, there is no difference in the number of rotations, so the carrier 83 rotates at the same rotational speed and in the same rotational direction. - 83 drives the traveling crawlers 15L and 15R, respectively, and the vehicle moves straight.

Further, when a turning operation is performed from a straight-ahead state using the steering handle 170, the rotational power output from the variable speed motor shaft 32a of the HST 11 via the turning gear mechanism 18 is adjusted to the rotational speed according to the amount of steering of the steering handle 170. After that, each internal gear 82 is driven at the same rotational speed and in different rotational directions.

As a result, in one planetary gear mechanism 13L (13R) in which the internal gear 82 rotates in the same direction as the rotational direction of the carrier 83, the rotational speed of the carrier 83 is increased and combined. In the other planetary gear mechanism 13R (13L), since the internal gear 82 rotates in the opposite direction to the rotational direction of the carrier 83, the rotational speed of the carrier 83 is reduced and combined. As a result, the left and right running crawlers 15L and 15R are differentially operated to change the traveling direction of the vehicle.

As the amount of steering of the steering handle 170 increases, the engagement force of the multi-plate clutch 93 (96) increases, the speed difference between the left and right carriers 83 increases, and the turning radius of the vehicle decreases. If the steering wheel 170 continues to be turned, the carrier 83 will stop rotating in the planetary gear mechanism 13R (13L) on the side that performs deceleration and combination, and only the planetary gear mechanism 13L (13R) on the side that performs speed increase and combination will drive the vehicle. makes a brake turn centering around traveling crawler 15R, which is unable to rotate. When the steering wheel 170 is further turned, the multi-disc clutch 93 (96) is fully engaged, and the carrier rotates in the opposite direction in the planetary gear mechanism 13R (13L) on the side that performs deceleration and combination, thereby increasing and combining speed. The vehicle spins and turns in cooperation with the planetary gear mechanism 13L (13R) on the side.

As described above, the transmission 1 for a crawler vehicle according to the present invention has the following features:
A sun gear 81 that is a first element that includes a common HST 11 for shifting and turning, is provided with a straight gear mechanism and a swing gear mechanism that are connected in parallel to the HST 11, and receives an output from the straight gear mechanism 17; An internal gear 82 is a second element that receives the output from the swing gear mechanism 18, and a carrier 83/planet is a third element that combines the power of the first element with the power of the second element and outputs it to the left and right drive wheels. In the transmission for a vehicle equipped with planetary gear mechanisms 13L and 13R including a gear 84, the swing gear mechanism 18 includes a first multi-disc clutch 93 and a second multi-disc clutch 93, which can freely switch the rotation of the second element in the forward or reverse direction. It has a plate clutch 96, and the first and second multi-disc clutches 93 and 96 are connected to the steering handle 170, which is a steering instruction tool of the vehicle, when the instruction device is in a straight-ahead operating state. is disengaged, and in the steering state, one of the multi-disc clutches 93 and 96 is selectively engaged depending on the steering direction, and as the amount of steering increases, the multi-disc clutches 93 and 96 are engaged. They are interlocked to increase the degree of accuracy.
With this configuration, it is possible to use one HST 11 that drives the driving system power transmission mechanism and the swing system power transmission mechanism, and it is possible to suppress costs. Therefore, the capacity of various devices for supplying hydraulic oil can be reduced, and the engine power is consumed to drive only the HST 11, making it possible to provide a crawler vehicle with excellent energy savings.

Further, on the lower power transmission side of the first and second multi-disc clutches 93 and 96, an internal gear 82, which is the second element, is disable from rotation when both multi-disc clutches 93 and 96 are disengaged. A locking anti-turn brake 105 is provided.
With this configuration, when traveling straight, the output of the swing gear mechanism is reliably stopped, and only the power of the straight gear mechanism 17 is transmitted to the planetary gear mechanisms 13L and 13R to efficiently drive the drive wheels straight. When turning, the power of the turning gear mechanism 18 can be efficiently combined by the planetary gear mechanisms 13L and 13R, and the driving wheels can be driven to turn with the turning radius as instructed by the steering.

1 Transmission 11 HST
13L/13R Planetary gear mechanism 16 Mission case 17 Straight gear mechanism 18 Swing gear mechanism 31 Variable speed pump 32 Variable speed motor 82 Internal gear 92 First axis for turning 95 Second axis for turning 103 Third axis for turning 105 Anti-swing brake 110 4th axis for turning 114 5th axis for turning

Claims (2)

Equipped with a common continuously variable transmission for shifting and turning,
A linear gear mechanism and a swing gear mechanism are provided that are connected in parallel to the continuously variable transmission, and
a first element that receives an output from the linear gear mechanism, a second element that receives an output from the swing gear mechanism, and combines the power of the first element with the power of the second element and outputs the result to left and right drive wheels. A transmission for a traveling vehicle equipped with a planetary gear mechanism including a third element that
The swing gear mechanism includes a first multi-disc clutch and a second multi-disc clutch that can freely switch the rotation of the second element in a forward or reverse direction,
The first and second multi-disc clutches disengage both multi-disc clutches when the indicator is in a straight-ahead operating state, and disengage the multi-disc clutches according to the steering direction when the indicator is in a steering state. A transmission for a traveling vehicle, characterized in that one of the multi-disc clutches is selectively selected to be engaged, and the multi-disc clutch is interlocked so as to increase the degree of engagement of the multi-disc clutch as the amount of steering increases. Claim 1, wherein a brake is provided on the lower power transmission side of the first and second multi-disc clutches to fix the second element in a non-rotatable manner when both multi-disc clutches are disengaged. Transmission for traveling vehicles described in .

Images