Method for controlling a drive train which the travel

Abstract

The invention relates to a method for controlling a drive train (10) with an electric drive motor (14) and a transmission (16) when a working machine (12) reverses the direction of travel. The transmission (16) is configured to provide a first gear, in which the first shifting element (18) is in a closed state and the second shifting element (20) is in an open state, and a second gear, in which the first shifting element (18) is in an open state and the second shifting element (20) is in a closed state. The method has the following steps: detecting (50) a direction-of-travel change intention in the second gear and detecting (52) a deceleration behavior in order to determine a shift time from the second gear to the first gear as a function of the detected deceleration behavior and as a function of a maximum load-carrying capacity of the first shift element (18). The first shifting element (18) is adjusted (56) at the determined shifting time in order to shift back without interruption of traction force. The invention further relates to a working machine (12).

Description

Technical Field

[0001] The invention relates to a method for controlling a drive train when reversing the direction of travel on a work machine. Background Art

[0002] In the drive train of a work machine, the transmission is typically designed for the drive motor. For example, environmental protection may necessitate replacing the internal combustion engine with an electric drive motor in the future. Under low requirements and in simple drive trains, this replacement can be relatively straightforward. However, certain driving functions may be limited by the performance and other specific characteristics of electric motors compared to internal combustion engines. For example, electric motors have significantly greater inertia than internal combustion engines or even hydraulic motors, even at comparable power. Consequently, the rotor of the electric motor can introduce significant forces into the drive train at the end of forward drive by the electric motor. This can place significant loads on the corresponding shifting elements of the transmission, particularly when they are engaged. Consequently, downshifting as a power shift, for example, when reversing the driving direction, may no longer be possible without difficulty. Instead, during such power shifts, the shifting elements may become overloaded, depending on the shift timing and driving conditions. For complex work processes or certain work machines, these limitations can hinder the conversion to an electric drive motor. Summary of the Invention

[0003] A first aspect relates to a method for controlling a drive train when reversing the direction of travel of a work machine. The drive train may be configured to provide driving power to the work machine. Alternatively or additionally, the drive train may be configured to provide power output to the work machine. The drive train may be controlled, for example, by a control device. The reversal of driving direction may be a reverse operation. When reversing the driving direction from forward travel, for example, deceleration may be performed and then acceleration may be performed in the opposite direction.

[0004] A work machine may be configured, for example, as an agricultural machine or a construction machine. An example of an agricultural machine is a tractor. An example of a construction machine is a backhoe loader. In both backhoe loaders and tractors, it is generally desirable to perform power shifts when the direction of travel is reversed. For example, in these work machines, brief stops for gear changes during a reversal of travel should be avoided.

[0005] The drive train includes an electric drive motor. The electric drive motor can be configured to convert electrical energy into mechanical energy. The electric drive motor can also optionally be configured for regeneration. The electric drive motor can be configured, for example, as a synchronous motor or an asynchronous motor.

[0006] A drive train includes a transmission. For example, the transmission can transmit drive power from an electric drive motor to an output of a work machine. During this transmission, the respective speeds and torques can be converted. The transmission includes a first shifting element and a second shifting element. The shifting element can be configured to be adjusted between a disengaged state and a engaged state. The shifting element can be adjusted to the disengaged state, for example, by actuation. In the engaged state, the shifting element can connect two parts, such as two shafts of a transmission, to each other in a rotationally fixed manner. In the disengaged state, the torque transmission between the two parts via the shifting element can be interrupted. The shifting element can be configured, for example, as a friction-locking or positive-locking clutch. An example of a friction-locking clutch is a multi-plate clutch. An example of a positive-locking clutch is a dog clutch. The shifting element can be configured as a brake. For example, in its engaged state, the brake can lock a rotating part against a stationary component, such as a transmission housing, through a rotationally fixed connection. The shifting element can be configured, for example, to be electrically or hydraulically actuated.

[0007] The transmission is designed to provide two gears. In first gear, the first shifting element is engaged and the second shifting element is disengaged. In second gear, the first shifting element is disengaged and the second shifting element is engaged. Therefore, to change gears, for example, both shifting elements are adjusted. The first gear may correspond to a fixed transmission ratio between the input and output shafts of the transmission. The second gear may be designed for higher driving speeds than the first gear. The first gear is used, for example, for starting off. The second gear is used, for example, for long-distance driving. When reversing driving direction from a high speed, the driving direction is typically shifted back from the second gear to the first gear before the change of driving direction occurs. The change of driving direction may correspond to a reversal of driving direction. The transmission may optionally be designed to provide a neutral gear, for example, when both shifting elements are disengaged. The transmission may optionally be designed to provide a parking brake function, for example, when both shifting elements are engaged. The two engaged shifting elements can, for example, lock the transmission. This prevents the work machine from rolling away.

[0008] The drive train can be configured, for example, to enable both forward and reverse travel in both first and second gear. For this purpose, a reverse assembly can be activated, for example, downstream of the transmission section providing the two gears. Alternatively, the direction of rotation of the electric drive motor can also be reversed.

[0009] The method comprises the following steps: detecting a desired change of direction in second gear. When the desired change of direction is detected, the work machine may, for example, be traveling at a high speed. This detection can be performed, for example, using a control element of the work machine, such as a direction selector lever. The desired change of direction can correspond to a corresponding operator input by the driver. The desired change of direction can correspond to a desire to switch from forward to reverse or vice versa. If the desired change of direction occurs in second gear, it is advisable to downshift to first gear at a certain point in time. After the reversal of direction is complete, the work machine can then be accelerated again in first gear.

[0010] The method comprises the following steps: detecting the deceleration behavior of the work machine in response to a desired change of direction of travel. The deceleration behavior can correspond to a speed gradient after the desired change of direction of travel is detected. When the work machine is traveling on inclined terrain, for example, the work machine may decelerate more or less drastically. Furthermore, the deceleration behavior can be influenced by the load and, alternatively or additionally, by the use of regenerative and service brakes. The deceleration can be performed by the work machine in response to the detected desired change of direction of travel. From the deceleration behavior, the speed curve of the work machine and, alternatively or additionally, the time of the reversal of the direction of travel can be calculated or estimated, for example, using a formula or a tabular comparison.

[0011] The method includes the following steps: determining a shifting time from the second gear to the first gear based on a detected deceleration behavior and a maximum load capacity of a first shifting element. The shifting time may be the time at which actuation and, therefore, adjustment of the shifting element is initiated. The shifting time may be determined as a time difference from a reference time. The shifting time may be determined relative to the time at which a change in driving direction is detected. The shifting from the second gear to the first gear may involve closing the first shifting element and opening the second shifting element. The determined shifting time may involve closing only the first shifting element. Alternatively, the determined shifting time may also involve opening the second shifting element. The maximum load capacity of the shifting element may be the maximum speed difference of the shifting element during closing. The maximum load capacity of the shifting element may be the maximum thermal energy that can be supplied to the shifting element during closing. For example, if the inertia and speed difference of the parts rotating relative to each other during closing are so high that the shifting element overheats, the shifting element is overloaded. Heating of the shifting element during closing may be caused, for example, by friction. The detected deceleration behavior can be used to determine shifting times so that overload is avoided. For example, during a reverse maneuver, a shift can be performed when the speed difference between the shifting elements is sufficiently small. The shifting times can be determined, for example, using a table comparison or a performance map. For example, the shifting times can be determined so that the load on the first and / or second shifting elements is minimized or at least very low.

[0012] The method includes the following steps: adjusting a first shifting element at a predetermined shifting time so as to shift back from the second gear to the first gear without interrupting traction. During this process, the work machine can, for example, continuously accelerate in the new direction of travel. Alternatively, the second shifting element can be adjusted at the shifting time or at another predetermined shifting time assigned to the second shifting element. The predetermined shifting time prevents overloading of the first shifting element even during power shifts. Consequently, despite the high inertia of the electric drive motor, shifts can be performed under load rather than at a standstill. Furthermore, the inertia is taken into account when adjusting the first shifting element, allowing actuation to be initiated sufficiently early. Thus, even if the transmission is originally designed for a drive train with an internal combustion engine or a hydraulic motor, power shifts can be implemented in a drive train with an electric drive motor. The electric drive motor can be retrofitted into the drive train.

[0013] Another embodiment of the method provides for determining the shifting time additionally as a function of the shifting time of the first shifting element. The shifting time of the shifting element may, for example, be the duration between the start and end of actuation. The shifting time of the shifting element may, for example, be the duration from the open state to the closed state. Taking the shifting time into account allows for control delays in the first shifting element to be taken into account. Thus, when determining the shifting time, for example, the onset of friction at the first shifting element or the maximum friction effect in the shifting element may be taken into account to minimize the load on the first shifting element during backshifting. Alternatively or additionally, the shifting time may be additionally determined as a function of the shifting time of the second shifting element. For example, the first shifting element may be adjusted by means of a hydraulic actuator, in particular a pressure-modulating piston. This results in a significant time delay between the control signal, the pressure buildup, and, alternatively or additionally, the onset of friction at the first shifting element. The shifting time may be a fixed, predetermined variable or determined, for example, as a function of influencing factors such as the driving state and environmental parameters. If the shifting time is a fixedly predetermined variable, the method can be easily implemented. If the shifting time is variably determined, the load on the first shifting element can be made particularly low or, alternatively or additionally, suitable shifting times can be determined particularly reliably.

[0014] Another embodiment of the method provides for determining the shifting time of the first shifting element in a temperature-dependent manner. The temperature may be the temperature of the hydraulic oil of the actuator of the first shifting element. It may also be an external or internal temperature. For example, since the viscosity of the hydraulic oil changes with temperature, the temperature can have a significant effect on the shifting time of the first shifting element. Taking the temperature into account allows for particularly accurate determination of the shifting time. In addition, other influencing factors may also be taken into account when determining the shifting time of the first shifting element.

[0015] In another embodiment of the method, the shifting time is determined so that the first shifting element is fully engaged when the driven speed reaches zero. The driven speed can correspond to the speed at the output shaft of the transmission. At zero driven speed, the working machine can just change its direction of travel. By fully engaging the first shifting element at zero driven speed, the first shifting element is lightly loaded. Thus, even if the first shifting element is designed for very low loads and the electric drive has a high inertia, a power shift can be achieved without loss and with minimal wear. Alternatively, for example, full engagement can also be achieved at the earliest or latest when the driven speed reaches zero.

[0016] In another embodiment of the method, the shifting times are determined such that the first shifting element is fully engaged upon reaching a predetermined output speed, which is in the opposite direction of rotation to that when the intended change of driving direction is detected. The predetermined output speed can, for example, be fixedly predetermined. This makes the method particularly simple to implement. The predetermined output speed, when the rotational direction is opposite to that when the intended change of driving direction is detected, can also be determined based on vehicle state variables, such as a determined deceleration behavior. The predetermined output speed, when the rotational direction is opposite to that when the intended change of driving direction is detected, can also take into account, for example, the load on the second shifting element. By achieving full engagement only when driving in the new direction of travel, shocks in the drive train caused by shifting gears under load can be particularly effectively avoided. Furthermore, a defined torque can be introduced into the transmission by the electric drive motor, making the load on the first shifting element very precisely known in advance.

[0017] In another embodiment of the method, a predetermined output speed, which is in a rotational direction opposite to the rotational direction when the desired direction change is detected, is determined as a function of the load of the first shifting element during the reverse shift. For example, a maximum output speed, which is in a rotational direction opposite to the rotational direction when the desired direction change is detected, can be predetermined at which excessive wear and, alternatively or additionally, damage to the first shifting element does not occur. For this purpose, the load of the first shifting element during the reverse shift into first gear can be determined as a function of the detected deceleration behavior.

[0018] In another embodiment of the method, the method additionally comprises the step of determining the load of the first shifting element when shifting back into the first gear as a function of the detected deceleration behavior. Furthermore, the method may further comprise the step of determining the shifting time such that the load on the first shifting element caused by the backshift remains below the maximum load-bearing capacity of the first shifting element.

[0019] In another embodiment of the method, the method includes decelerating the work machine in response to a detected change of direction of travel by means of regeneration using an electric drive motor. This allows for particularly efficient reversal of direction of travel. During regeneration, the energy storage device of the drive train can be charged by the electric drive motor. The energy storage device can, for example, comprise a battery and be configured to supply electrical energy to the electric drive motor to generate propulsion. Regeneration brakes the electric drive motor, so that its inertia does not actually affect the first shifting element as strongly during reverse shifting. Regeneration can be controlled so that, during reverse shifting, the load on the first shifting element remains below its maximum load-bearing capacity at a predetermined shifting time.

[0020] A second aspect of the present invention relates to a work machine. The work machine can be configured to perform the method according to the first aspect. The respective advantages and further features are derived from the description of the first aspect, wherein the design of the first aspect also forms the design of the second aspect, and vice versa.

[0021] The work machine has a drive train, a detection device, and a control device. The detection device may, for example, have respective sensors and, alternatively or additionally, receive the respective information to be detected from a vehicle bus. The control device may, for example, be configured as a transmission control unit. The control device may include a microprocessor. The control device may be configured to generate respective control signals for adjusting respective shifting elements and to transmit the control signals to actuators of the shifting elements.

[0022] The drive train includes an electric drive motor and a transmission. The transmission includes a first shifting element and a second shifting element. The transmission is configured to provide a first gear and a second gear. In the first gear, the first shifting element is engaged and the second shifting element is disengaged, and in the second gear, the first shifting element is disengaged and the second shifting element is engaged. A detection device is configured to detect a driving direction change request in the second gear and to detect a deceleration behavior of the work machine in response to the driving direction change request. The control device is configured to determine a shifting time from the second gear to the first gear based on the detected deceleration behavior and the maximum load capacity of the first shifting element, and to adjust the first shifting element at the determined shifting time so as to shift back from the second gear to the first gear without interrupting traction. This adjustment may cause the first shifting element to engage. The control device may optionally be configured to adjust both shifting elements at the determined shifting time so as to shift back from the second gear to the first gear without interrupting traction. The second shifting element may then be disengaged.

[0023] In another embodiment of the work machine, the transmission includes a planetary gear set having a sun gear, a planet carrier, and a ring gear. The sun gear, planet carrier, and ring gear may constitute the rotating elements of the planetary gear set. The respective planet gears may be rotatably mounted on the planet carrier, meshing with the sun gear and the ring gear. The transmission can compactly provide a high transmission ratio using the planetary gear set. The first shifting element may be configured as a brake, by means of which the ring gear can be fixed. The second shifting element may be configured as a clutch, by means of which the planetary gear set can be locked. For example, in the engaged state, the second shifting element may connect two rotating elements of the planetary gear set, such as the ring gear and the sun gear, to each other in a rotationally fixed manner. In the locked state, all rotating elements of the planetary gear set may rotate at the same angular velocity, for example. This configuration of the planetary gear set allows the transmission to easily provide a parking brake function and a neutral gear. To activate the parking brake, both shifting elements may be engaged. To activate the neutral gear, both shifting elements may be disengaged. The sun gear may be configured as the drive element of the planetary gear set. The sun gear can, for example, form the input shaft of the transmission. The planet carrier can be designed as the output element of a planetary gear set. The planet carrier can, for example, form the output shaft of the transmission. The transmission can have a respective spur gear set on the output or input side for higher transmission ratios in the torque flow.

[0024] In another embodiment of the work machine, both shift elements are preloaded toward their respective closed positions. If the shift elements are not actuated, for example by pressurizing their actuators, they automatically shift into their respective closed positions. This allows for safe downshifts. Furthermore, if hydraulic pressure is lost, the drive train is automatically locked, for example. This makes the work machine particularly safe.

[0025] In another embodiment of the work machine, both shift elements are designed to be hydraulically actuated. For example, each of the two shift elements may include a hydraulic cylinder as an actuator. Hydraulically actuated shift elements can, for example, transmit particularly high loads and can be actuated simply and reliably in the work machine. The method for controlling a drive train during a reversal of travel direction on a work machine according to the first aspect can take into account or even compensate for the slow closing behavior of the hydraulically actuated shift elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A method for controlling a drive train when reversing the direction of travel with a work machine is schematically illustrated;

[0027] Figure 2 A working machine is schematically illustrated, which is configured to perform a task according to Figure 1 Methods;

[0028] Figure 3 Schematically illustrates the Figure 1 The method controls the first timing of reversing the driving direction;

[0029] Figure 4 Schematically illustrates the Figure 1 The method controls the first timing of reversing the driving direction. DETAILED DESCRIPTION

[0030] Figure 1 The method for controlling the drive train 10 when reversing the driving direction with the work machine 12 is schematically explained. The work machine 12 is designed to carry out the method. Figure 2. The drive train 10 includes an electric drive motor 14 and a transmission 16. The transmission 16 has a first shifting element 18, a second shifting element 20, and a planetary gear set 22. The planetary gear set 22 includes a sun gear 24, a planet carrier 26, and a ring gear 28. A plurality of planetary gears are rotatably mounted on the planet carrier 26 and mesh with the sun gear 24 and the ring gear 28, respectively. The transmission 16 is configured to provide a first gear and a second gear for transmitting drive power from the drive motor 14 to an output 30 of the work machine 12. The second shifting element 20 is configured as a clutch, by means of which the planetary gear set 22 can be locked by connecting the ring gear 28 to the sun gear 24 in a rotationally fixed manner. The first shifting element 18 is configured as a brake, by means of which the ring gear can be locked in the transmission housing 32. The sun gear 24 is configured as the drive element of the planetary gear set 22 and is connected in a rotationally fixed manner to the motor shaft of the electric drive motor 14. The planet carrier 26 is designed as the output element of the planetary gear set 22 and is connected to the output element 30 of the work machine 12. The shift element 18, designed as a brake, can be hydraulically actuated by means of a pressure-modulating piston and preloaded toward its closed position. Therefore, in the event of a pressure loss or when both shift elements 18 and 20 are not actuated, they remain in their closed position and provide a parking brake function by locking the planetary gear set 22 and, therefore, the drive train 10. The transmission 16 is designed to provide a first gear and a second gear. In the first gear, the first shift element 18 is closed and the second shift element 20 is open. In the second gear, the first shift element 18 is open and the second shift element 20 is closed. The transmission 16 can also provide a neutral gear by opening both shift elements 18 and 20.

[0031] The method includes a step 50 of detecting a driving direction change request in the second gear using the detection device 40. The work machine 12 is decelerated in response to the detected driving direction change request by means of regeneration using the electric drive motor 14 and accelerated when the driving direction changes to the opposite direction. In step 52 of the method, the deceleration behavior of the work machine 12 in response to the driving direction change request is detected using the detection device 40. In step 54, the shifting time from the second gear to the first gear is determined using the control device 42 of the work machine 12 based on the detected deceleration behavior and the maximum load capacity of the first shifting element. In step 56, the first shifting element 18 is adjusted at the determined shifting time using the control device 42 to shift back from the second gear to the first gear without interrupting traction. The shifting time of the first shifting element 18, which is determined based on the oil temperature of the pressure modulation piston of the first shifting element 18 detected by the detection device 40, is also taken into account when determining the shifting time.

[0032] When reversing from second gear, a continuous output speed profile can be achieved with the reverse shift without interrupting traction. The speed gradient and negative motor torque caused by regeneration counteract the moment of inertia of the electric drive motor 14 during deceleration. The speed difference in the first shifting element 18 is reduced by regulating the electric drive motor 14. By regulating the first shifting element 18 at the specified shifting time, the brake load—that is, the load on the first shifting element 18—remains within the permissible range despite the high moment of inertia on the drive side. Due to the low speed difference in the brake, the load on the brake is also low. Furthermore, regeneration allows for energy recovery when changing direction of travel.

[0033] Figure 3 In a diagram, the Figure 1 This is the first possible timing for a reversal of driving direction controlled by a method. Time is plotted on the abscissa. Line 60 illustrates the speed curve of the electric drive motor 14. Line 62 illustrates the speed difference in the first shifting element 18. Line 64 illustrates the speed difference in the second shifting element 20. At time t1, a change in driving direction is detected. As can be seen, the working machine 12 is decelerated by the electric drive motor 14, and the motor speed itself decreases. The shifting times are determined so that the first shifting element 18 is fully engaged when the output speed reaches zero. Accordingly, lines 60 and 62 intersect the abscissa at time t3. Therefore, the load is extremely low when the first shifting element 18 is engaged. Immediately after this, the first shifting element 18 is engaged, so the speed difference is zero. However, there may also be a small amount of residual slip.

[0034] exist Figure 3 In the lower portion of the diagram, line 66 plots the pressure curve in the actuator of the first shifting element 18, and line 68 plots the pressure curve in the actuator of the second shifting element. At time t2, the pressure at the first shifting element 18 is reduced to close it. At time t2, the pressure at the second shifting element 20 is also increased to open it. As can be seen, the closing process of the first shifting element 18, like the opening process of the second shifting element 20, lasts from time t2 to time t3. This corresponds to the shifting time of the first shifting element 18 when it is closed. Accordingly, the shifting time from the second gear to the first gear is determined as the time difference from time t1. At time t2, the pressure at the first shifting element 18 is reduced to close it.

[0035] Figure 4 In a chart, the use of Figure 1 The second possible sequence of the driving direction reversal is controlled by the method. The structure of the diagram is similar to Figure 3 . However, in this time sequence, the shifting times are determined so that when a predetermined output speed is reached, which is opposite to the direction of rotation when the desire to change driving direction is detected, the first shifting element 18 is fully engaged. At time t3, the reversal of driving direction has already been completed, as can be seen on line 60.

[0036] Reference Signs List

[0037] 10 Drivetrain

[0038] 12 Operating machinery

[0039] 14 Drive motor

[0040] 16 Transmission

[0041] 18 First shift element

[0042] 20 Second shift element

[0043] 22 planetary gear sets

[0044] 24 Sun gear

[0045] 26 planet carrier

[0046] 28 Ring gear

[0047] 30 Follower

[0048] 32 shell

[0049] 40 Testing Equipment

[0050] 42 Control Equipment

[0051] 50 Steps: Detecting the Intention to Change Direction

[0052] 52 Steps: Detecting Slowdown Behavior

[0053] Step 54: Determine the shift timing

[0054] Step 56: Adjusting the first shift element

[0055] Line 60: Speed ​​change curve of the drive motor

[0056] Lines 62 and 64: Speed ​​difference of shifting elements

[0057] Lines 66 and 68: Pressure curves at the actuator of the shift element

[0058] t1: Detection of a change in driving direction

[0059] Time t2: Pressure reduction / increase in the shifting element

[0060] t3 time point: end point of the gear shift process

Claims

1. A method for controlling a drive train (10) when reversing the direction of travel of a working machine (12), wherein: The drive train (10) comprises an electric drive motor (14) and a transmission (16), the transmission having a first shifting element (18) and a second shifting element (20), wherein the transmission (16) is configured to provide a first gear and a second gear, in which the first shifting element (18) is closed and the second shifting element (20) is open, and in which the first shifting element (18) is open and the second shifting element (20) is closed, and wherein the method comprises at least the following steps: - detecting (50) a desire to change the driving direction in the second gear; - detecting (52) a deceleration behavior of the work machine (12) in response to an intention to change the direction of travel; - determining (54) a shifting time from the second gear to the first gear as a function of the detected deceleration behavior and as a function of the maximum load capacity of the first shifting element (18); and - adjusting (56) the first shifting element (18) at a determined shifting time in order to shift back from the second gear into the first gear without interruption of traction force.

2. The method according to claim 1, characterized in that The shifting time is additionally determined as a function of the shifting time of the first shifting element (18).

3. The method according to claim 2, characterized in that A shifting time of the first shifting element (18) is determined as a function of temperature.

4. The method according to any one of the preceding claims, characterized in that The shifting time is determined such that when the output speed reaches zero, the first shifting element (18) is completely engaged.

5. The method according to any one of the preceding claims, characterized in that The shifting time is determined such that the first shifting element (18) is completely engaged when a predetermined output speed is reached, the rotational direction of which is opposite to the rotational direction when the driving direction change intention is detected.

6. The method according to claim 5, characterized in that A predetermined output speed, which has a rotational direction opposite to the rotational direction when a desire to change driving direction is detected, is determined as a function of the load of the first shifting element (18) during backshifting.

7. The method according to any one of the preceding claims, characterized in that The method additionally comprises the following steps: - determining the load of the first shifting element (18) when shifting back into the first gear in dependence on the detected deceleration behavior; and - The shifting time is determined such that the load on the first shifting element (18) caused by the backshift remains below the maximum load-bearing capacity of the first shifting element (18).

8. The method according to any one of the preceding claims, characterized in that The method comprises: decelerating the work machine (12) by means of regeneration using the electric drive motor (14) in response to a detected desire to change the direction of travel.

9. A working machine comprising a drive system, a detection device (40) and a control device (42), wherein: The drive train (10) has an electric drive motor (14) and a transmission (16), the transmission having a first shifting element (18) and a second shifting element (20), wherein the transmission (16) is configured to provide a first gear and a second gear, in which the first shifting element (18) is closed and the second shifting element (20) is open, and in the second gear, the first shifting element (18) is open and the second shifting element (20) is closed, wherein the detection device (40) is configured to detect a change of driving direction in the second gear and to detect a deceleration behavior of the working machine (12) in response to the change of driving direction, and wherein the control device (42) is configured to determine a shifting time point from the second gear to the first gear as a function of the detected deceleration behavior and as a function of the maximum load capacity of the first shifting element (18), and to adjust the first shifting element (18) at the determined shifting time point so as to switch back from the second gear to the first gear without interruption of traction.

10. The working machine (12) according to claim 9, characterized in that The transmission (16) has a planetary gear set (22), the planetary gear set having a sun gear (24), a planet carrier (26) and a ring gear (28), wherein the first shifting element (18) is constructed as a brake, by means of which the ring gear (28) can be fixed, wherein the second shifting element (20) is constructed as a clutch, by means of which the planetary gear set (22) can be interlocked, wherein the sun gear (24) is constructed as a driving element of the planetary gear set (22), and wherein the planet carrier (26) is constructed as a driven element of the planetary gear set (22).

11. The working machine (12) according to claim 9 or 10, characterized in that The two shifting elements (18, 20) are preloaded in the direction of their respective closed position.

12. The working machine (12) according to any one of the preceding claims 9 to 11, characterized in that The two shifting elements (18, 20) are designed to be hydraulically actuable.

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