JP2022033089A - Working machine - Google Patents

Abstract

To provide a working machine capable of easily reducing shift shock.SOLUTION: The working machine includes: a travel motor capable of switching the rotational speed between a first speed and a second speed higher than the first speed; a travel switching valve 34 capable of switching between a first state in which the rotational speed of the travel motor is set to the first speed and a second state in which the rotational speed of the travel motor is set to the second speed; a changeover switch that performs a shift command of either acceleration or deceleration; a travel operation unit 54 that has an operation valve capable of changing the pressure of the hydraulic oil acting on the traveling pump responding to the operation on an operation member; an operation valve 69 that is connected to the operation valve at the upstream side or downstream side of the operation valve and is capable of controlling the hydraulic oil flowing to the operation valve; and a control unit 60 that performs a shock reduction control of reducing the opening of the operation valve by outputting a control signal to the operation valve when switching from the first state to the second state. The control unit sets a reduction amount of the opening of the operation valve based on the degree of straightness of the chassis.SELECTED DRAWING: Figure 1

Description

The present invention relates to working machines such as skid steer loaders, compact truck loaders, and backhoes, for example.

Conventionally, there is a technique shown in Patent Document 1 as a technique for decelerating and increasing the speed of a working machine. The hydraulic system of the working machine of Patent Document 1 includes a hydraulic pump that discharges hydraulic oil, a hydraulic switching valve that can switch to a plurality of switching positions according to the pressure of the hydraulic oil, and a speed according to the switching position of the hydraulic switching valve. Is equipped with a variable traveling hydraulic system.

JP-A-2017-179922

In the working machine of Patent Document 1, since the bleed oil passage is provided in the pressure receiving portion of the hydraulic pressure switching valve, it is possible to reduce the shift shock when the working machine is accelerated or decelerated. However, in Patent Document 1, a bleed oil passage must be provided in order to reduce shift shock, and the number of parts increases.
The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a working machine capable of easily reducing shift shock.

The technical measures taken by the present invention to solve the technical problems are as follows.
The working machine can be rotated by a prime mover, a traveling pump operated by the power of the prime mover and discharging hydraulic oil, and hydraulic oil discharged by the traveling pump, and the rotation speed is higher than the first speed and the first speed. A traveling motor that can be switched to a higher second speed, a machine body provided with the prime mover, a traveling pump, and a traveling motor, a first state in which the rotational speed of the traveling motor is set to the first speed, and the traveling motor. A travel switching valve that can switch the rotation speed of the vehicle to the second state of the second speed, a changeover switch that issues a shift command for either speed increase or deceleration, and the travel pump according to the operation of the operating member. A traveling operation device having an operation valve capable of changing the pressure of the hydraulic oil acting on the operation valve, and an operation that is connected to the operation valve on the upstream side or the downstream side of the operation valve and can control the hydraulic oil flowing through the operation valve. The control includes a valve and a control device that performs shock reduction control for reducing the opening degree of the actuated valve by outputting a control signal to the actuated valve when switching from the first state to the second state. The device sets the amount of decrease in the opening degree of the operating valve based on the degree of straightness of the machine.

The actuated valve is a valve in which the opening degree increases as the control value corresponding to the control signal increases and the opening degree decreases as the control value decreases, and the control device is the airframe. The control device sets the amount of decrease in the control value as the amount of decrease in the opening degree of the actuated valve based on the degree of straightness of the operating valve, and calculates the decrease value in the shock reduction control based on the amount of decrease. In the reduction section until the control value reaches the reduction value, the first reduction rate of the control value from the start point to the end point of the reduction section is made constant.

In the reduction section until the control value reaches the reduction value, the control device sets the second reduction rate of the control value from the start point of the reduction section to the middle of the reduction section from the middle to the end point of the reduction section. It is made larger than the third decrease rate of the control value.
The control device changes the timing when the traveling switching valve is switched from the second state to the first state according to the degree of straightness.

When the degree of straightness is large, the control device sets a large amount of decrease, and when the degree of straightness is small, the amount of decrease is set small.
The working machine includes a first traveling device provided on the left side of the machine body and a second traveling device provided on the right side of the machine body, and the traveling motor provides traveling power to the first traveling device. It is a second traveling motor that transmits traveling power to the first traveling motor and the second traveling device, and the traveling pump can operate the first traveling motor and the second traveling motor, and the traveling. The switching valve can switch the first traveling motor and the second traveling motor between the first speed and the second speed.

According to the present invention, the shift shock can be easily reduced.

It is a figure which shows the hydraulic system (hydraulic circuit) of a work machine. It is a figure which shows the relationship between the straightness degree SV and the decrease amount ΔF11. It is a figure which showed the relationship between the rotation speed of a prime mover and the switching of a traveling motor when the traveling motor is decelerated. It is a figure which showed the relationship between the rotation speed of a prime mover and the switching of a traveling motor when the traveling motor is decelerated. It is a figure which shows the modification which changed the operation device into the operation device which operates electrically, such as a joystick. It is a side view which shows the truck loader which is an example of a working machine.

Hereinafter, a hydraulic system for a working machine according to the present invention and a preferred embodiment of the working machine provided with the hydraulic system will be described with reference to the drawings as appropriate.
FIG. 6 shows a side view of the working machine according to the present invention. FIG. 6 shows a compact truck loader as an example of a working machine. However, the working machine according to the present invention is not limited to the compact truck loader, and may be, for example, another type of loader working machine such as a skid steer loader. Further, it may be a working machine other than the loader working machine.

As shown in FIG. 6, the working machine 1 includes a machine body 2, a cabin 3, a working device 4, and a traveling device 5. In the embodiment of the present invention, the front side (left side of FIG. 6) of the driver seated in the driver's seat 8 of the work machine 1 is the front, the rear side of the driver (right side of FIG. 6) is the rear, and the left side of the driver (FIG. 6). The front side of No. 6) will be described as the left side, and the right side of the driver (the back side of FIG. 6) will be described as the right side. Further, the horizontal direction, which is a direction orthogonal to the front-rear direction, will be described as the body width direction. The direction from the center of the machine 2 to the right or left side will be described as the outside of the machine. In other words, the outside of the airframe is the width direction of the airframe and the direction away from the airframe 2. The direction opposite to the outside of the aircraft will be described as the inside of the aircraft. In other words, the inside of the machine is the width direction of the machine and the direction approaching the body 2.

The cabin 3 is mounted on the airframe 2. The cabin 3 is provided with a driver's seat 8. The working device 4 is attached to the machine body 2. The traveling device 5 is provided on the outside of the machine body 2. A motor 32 is mounted on the rear portion of the machine body 2.
The working device 4 has a boom 10, a working tool 11, a lift link 12, a control link 13, a boom cylinder 14, and a bucket cylinder 15.

The boom 10 is provided on the right side and the left side of the cabin 3 so as to be vertically swingable. The work tool 11 is, for example, a bucket, and the bucket 11 is provided at the tip end portion (front end portion) of the boom 10 so as to be vertically swingable. The lift link 12 and the control link 13 support the base portion (rear portion) of the boom 10 so that the boom 10 can swing up and down. The boom cylinder 14 expands and contracts to raise and lower the boom 10. The bucket cylinder 15 swings the bucket 11 by expanding and contracting.

The front parts of the left and right booms 10 are connected to each other by a deformed connecting pipe. The bases (rear parts) of the booms 10 are connected to each other by a circular connecting pipe.
The lift link 12, the control link 13, and the boom cylinder 14 are provided on the left side and the right side of the machine body 2, respectively, corresponding to the left and right booms 10.
The lift link 12 is provided vertically at the rear of the base of each boom 10. The upper part (one end side) of the lift link 12 is a pivot shaft 16 (first) near the rear part of the base of each boom 10.
It is rotatably supported around the horizontal axis via the pivot axis). Further, the lower portion (the other end side) of the lift link 12 is rotatably and rotatably supported around the horizontal axis via the pivot shaft 17 (second pivot shaft) toward the rear portion of the machine body 2. The second pivot shaft 17 is provided below the first pivot shaft 16.

The upper portion of the boom cylinder 14 is rotatably supported around a horizontal axis via a pivot shaft 18 (third pivot shaft). The third pivot shaft 18 is the base of each boom 10 and is provided at the front of the base. The lower portion of the boom cylinder 14 is rotatably supported around a horizontal axis via a pivot shaft 19 (fourth pivot shaft). The fourth pivot shaft 19 is provided near the lower part of the rear part of the machine body 2 and below the third pivot shaft 18.

The control link 13 is provided in front of the lift link 12. One end of the control link 13 is rotatably supported around a horizontal axis via a pivot shaft 20 (fifth pivot shaft). The fifth pivot shaft 20 is the airframe 2, and is provided at a position corresponding to the front of the lift link 12. The other end of the control link 13 is rotatably supported around a horizontal axis via a pivot shaft 21 (sixth pivot shaft). The sixth pivot shaft 21 is a boom 10 and is provided in front of the second pivot shaft 17 and above the second pivot shaft 17.

By expanding and contracting the boom cylinder 14, each boom 10 swings up and down around the first pivot shaft 16 while the base of each boom 10 is supported by the lift link 12 and the control link 13, and the tip of each boom 10 Goes up and down. The control link 13 swings up and down around the fifth pivot shaft 20 as each boom 10 swings up and down. The lift link 12 swings back and forth around the second pivot shaft 17 as the control link 13 swings up and down.

Another work tool can be attached to the front of the boom 10 instead of the bucket 11. Another working tool is, for example, an attachment (spare attachment) such as a hydraulic crusher, a hydraulic breaker, an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, or a snow blower.
A connecting member 50 is provided at the front of the boom 10 on the left side. The connecting member 50 is a device for connecting the hydraulic device equipped in the spare attachment and the first pipe material such as a pipe provided in the boom 10. Specifically, the first pipe material can be connected to one end of the connecting member 50, and the second pipe material connected to the hydraulic device of the spare attachment can be connected to the other end. As a result, the hydraulic oil flowing through the first pipe material passes through the second pipe material and is supplied to the hydraulic equipment.

The bucket cylinder 15 is arranged near the front of each boom 10. By expanding and contracting the bucket cylinder 15, the bucket 11 is swung.
As each of the left and right traveling devices (first traveling device, second traveling device) 5, a crawler type (including semi-crawler type) traveling device is adopted in the present embodiment. A wheel-type traveling device having front wheels and rear wheels may be adopted.

The prime mover 32 is an internal combustion engine such as a diesel engine or a gasoline engine, an electric motor, or the like. In this embodiment, the prime mover 32 is, but is not limited to, a diesel engine.
Next, the hydraulic system of the working machine will be described.
As shown in FIG. 1, the hydraulic system of the working machine can drive the traveling device 5. The hydraulic system of the working machine includes a first traveling pump 53L, a second traveling pump 53R, a first traveling motor 36L, and a second traveling motor 36R.

The first traveling pump 53L and the second traveling pump 53R are pumps driven by the power of the prime mover 32. Specifically, the first traveling pump 53L and the second traveling pump 53R are swash plate type variable displacement axial pumps driven by the power of the prime mover 32. The first traveling pump 53L and the second traveling pump 53R have a pressure receiving portion 53a and a pressure receiving portion 53b on which a pilot pressure acts, and the angle of the swash plate is adjusted by the pilot pressure acting on the pressure receiving portions 53a and 53b. Be changed. By changing the angle of the slab, the output (discharge amount of hydraulic oil) and the discharge direction of the hydraulic oil of the first traveling pump 53L and the second traveling pump 53R can be changed.

The first traveling pump 53L and the first traveling motor 36L are connected by a circulating oil passage 57h, and the hydraulic oil discharged by the first traveling pump 53L is supplied to the first traveling motor 36L. The second traveling pump 53R and the second traveling motor 36R are connected by a circulating oil passage 57i, and the hydraulic oil discharged by the second traveling pump 53R is supplied to the second traveling motor 36R.
The first traveling motor 36L is a motor that transmits power to the drive shaft of the traveling device 5 provided on the left side of the machine body 2. The first traveling motor 36L can be rotated by the hydraulic oil discharged from the first traveling pump 53L, and the rotation speed (rotational speed) can be changed by the flow rate of the hydraulic oil. A swash plate switching cylinder 37L is connected to the first traveling motor 36L, and the rotation speed (rotation speed) of the first traveling motor 36L is also changed by expanding and contracting the swash plate switching cylinder 37L to one side or the other side. be able to. That is, when the swash plate switching cylinder 37L is contracted, the rotation speed of the first traveling motor 36L is set to a low speed (first speed), and when the swash plate switching cylinder 37L is extended, the first traveling motor 36L is set. The rotation speed of is set to high speed (second speed). That is, the rotation speed of the first traveling motor 36L can be changed between the first speed on the low speed side and the second speed on the high speed side.

The second traveling motor 36R is a motor that transmits power to the drive shaft of the traveling device 5 provided on the right side of the machine body 2. The second traveling motor 36R can be rotated by the hydraulic oil discharged from the second traveling pump 53R, and the rotation speed (rotational speed) can be changed by the flow rate of the hydraulic oil. A swash plate switching cylinder 37R is connected to the second traveling motor 36R, and the rotation speed (rotation speed) of the second traveling motor 36R is also changed by expanding and contracting the swash plate switching cylinder 37R to one side or the other side. be able to. That is, when the swash plate switching cylinder 37R is contracted, the rotation speed of the second traveling motor 36R is set to a low speed (first speed), and when the swash plate switching cylinder 37R is extended, the second traveling motor 36R is set. The rotation speed of is set to high speed (second speed). That is, the rotation speed of the second traveling motor 36R can be changed between the first speed on the low speed side and the second speed on the high speed side.

As shown in FIG. 1, the hydraulic system of the working machine includes a traveling switching valve 34. The travel switching valve 34 switches between a first state in which the rotation speed (rotation speed) of the travel motors (first travel motor 36L, second travel motor 36R) is set to the first speed and a second state in which the travel speed is set to the second speed. It is possible. The traveling switching valve 34 has a first switching valve 71L, 71R and a second switching valve 72.
The first switching valve 71L is a two-position switching valve that is connected to the swash plate switching cylinder 37L of the first traveling motor 36L via an oil passage and switches between the first position 71L1 and the second position 71L2. The first switching valve 71L contracts the swash plate switching cylinder 37L when it is in the first position 71L1, and expands the swash plate switching cylinder 37L when it is in the second position 71L2.

The first switching valve 71R is a two-position switching valve that is connected to the swash plate switching cylinder 37R of the second traveling motor 36R via an oil passage and switches to the first position 71R1 and the second position 71R2. The first switching valve 71R contracts the swash plate switching cylinder 37R at the first position 71R1 and expands the swash plate switching cylinder 37R at the second position 71R2.
The second switching valve 72 is a solenoid valve that switches between the first switching valve 71L and the first switching valve 71R, and is a two-position switching valve that can be switched between the first position 72a and the second position 72b by excitation. The second switching valve 72, the first switching valve 71L, and the first switching valve 71R are connected by an oil passage 41. The second switching valve 72 switches the first switching valve 71L and the first switching valve 71R to the first positions 71L1 and 71R1 when it is in the first position 72a, and the first switching valve 71L and when it is in the second position 72b. The first switching valve 71R is switched to the second positions 71L2 and 71R2.

That is, when the second switching valve 72 is in the first position 72a, the first switching valve 71L is in the first position 71L1, and the first switching valve 71R is in the first position 71R1, the traveling switching valve 34 is in the first state. The rotation speed of the traveling motors (first traveling motor 36L, second traveling motor 36R) is set to the first speed. When the second switching valve 72 is in the second position 72b, the first switching valve 71L is in the second position 71L2, and the first switching valve 71R is in the second position 71R2, the traveling switching valve 34 is in the second state and the traveling motor. The rotation speed of (first traveling motor 36L, second traveling motor 36R) is set to the second speed.

Therefore, the traveling switching valve 34 can switch the traveling motor (first traveling motor 36L, second traveling motor 36R) between the first speed on the low speed side and the second speed on the high speed side.
Switching between the first speed and the second speed in the traveling motor can be performed by the switching unit. The switching unit is, for example, a changeover switch 61 connected to the control device 60, and can be operated by an operator or the like. The switching unit (changeover switch 61) has a second speed (first state) to a second speed.
It is possible to switch between an increase in speed (second state) and a deceleration in which the second speed (second state) is switched to the first speed (first state).

The control device 60 is composed of a CPU, a semiconductor such as an MPU, an electric / electronic circuit, and the like. The control device 60 switches the traveling switching valve 34 based on the switching operation of the changeover switch 61. The changeover switch 61 is a push switch. For example, when the traveling motor is pressed in the first speed state, the changeover switch 61 outputs a command to set the traveling motor to the second speed (a command to set the traveling switching valve 34 to the second speed) to the control device 60. Will be done. Further, when the traveling motor is pressed in the second speed state, the changeover switch 61 outputs a command to set the traveling motor to the first speed (a command to set the traveling switching valve 34 to the first state) to the control device 60. .. The changeover switch 61 may be a push switch that can be held ON / OFF, and when it is OFF, a command for holding the traveling motor at the first speed is output to the control device 60 and is ON. In this case, a command for holding the traveling motor at the second speed is output to the control device 60.

When the control device 60 obtains a command to put the traveling switching valve 34 into the first state, the control device 60 degausses the solenoid of the second switching valve 72 to put the traveling switching valve 34 into the first state. Further, when the control device 60 acquires a command to put the traveling switching valve 34 into the second state, the control device 60 excites the solenoid of the second switching valve 72 to put the traveling switching valve 34 into the second state.
The hydraulic system of the working machine includes a first hydraulic pump P1, a second hydraulic pump P2, and an operating device (traveling operating device) 54. The first hydraulic pump P1 is a pump driven by the power of the prime mover 32, and is composed of a constant capacity type gear pump. The first hydraulic pump P1 can discharge the hydraulic oil stored in the tank 22. In particular, the first hydraulic pump P1 discharges hydraulic oil mainly used for control. For convenience of explanation, the tank 22 for storing the hydraulic oil may be referred to as a hydraulic oil tank. Further, among the hydraulic oil discharged from the first hydraulic pump P1, the hydraulic oil used for control may be referred to as pilot oil, and the pressure of the pilot oil may be referred to as pilot pressure.

The second hydraulic pump P2 is a pump driven by the power of the prime mover 32, and is composed of a constant capacity type gear pump. The second hydraulic pump P2 can discharge the hydraulic oil stored in the tank 22, and supplies the hydraulic oil to, for example, the oil passage of the working system. For example, the second hydraulic pump P2 supplies hydraulic oil to the boom cylinder 14 that operates the boom 10, the bucket cylinder 15 that operates the bucket, and the control valve (flow control valve) that controls the preliminary hydraulic actuator that operates the preliminary hydraulic actuator. do.

The traveling operation device 54 is a device for operating a traveling pump (first traveling pump 53L, second traveling pump 53R), and the angle of the swash plate of the traveling pump (swash plate angle) can be changed. The traveling operation device 54 includes an operation member 59 such as an operation lever and a plurality of operation valves 55.
The operating member 59 is an operating lever that is supported by the operating valve 55 and swings in the left-right direction (body width direction) or in the front-rear direction. That is, the operating member 59 can be operated to the right and left from the neutral position N and can be operated forward and backward from the neutral position N with reference to the neutral position N. In other words, the operating member 59 can swing in at least four directions with respect to the neutral position N. For convenience of explanation, the front and rear directions, that is, the front-back direction is referred to as the first direction. Further, the bidirectional direction between the right side and the left side, that is, the left-right direction (airframe width direction) may be referred to as the second direction.

Further, the plurality of operating valves 55 are operated in common, that is, by one operating member 59. The plurality of operating valves 55 operate based on the swing of the operating member 59. A discharge oil passage 40 is connected to the plurality of operation valves 55, and hydraulic oil (pilot oil) from the first hydraulic pump P1 can be supplied via the discharge oil passage 40. The plurality of operating valves 55 are an operating valve 55A, an operating valve 55B, an operating valve 55C, and an operating valve 55D.

The operation valve 55A is an operation that outputs according to the operation amount (operation) of the previous operation when the operation member 59 is swung forward (one side) in the front-rear direction (first direction) (when the operation member 59 is operated forward). The pressure of the oil changes. The operation valve 55B is operated to output according to the operation amount (operation) of the rear operation when the operation member 59 is swung backward (the other) in the front-rear direction (first direction) (when the operation member 59 is rear-operated). The pressure of the oil changes. In the left-right direction (second direction), the operation valve 55C outputs when the operation member 59 swings to the right (one side) (when the operation member 59 is operated to the right) according to the operation amount (operation) of the right operation. The pressure of the hydraulic oil changes. The operation valve 55D outputs according to the operation amount (operation) of the left operation when the operation member 59 is swung to the left (the other) in the left-right direction (second direction) (when the operation member 59 is operated to the left). The pressure of the hydraulic fluid changes.

The plurality of operating valves 55 and the traveling pumps (first traveling pump 53L, second traveling pump 53R) are connected by a traveling oil passage 45. In other words, the traveling pump (first traveling pump 53L, second traveling pump 53R) is hydraulic pressure that can be operated by the hydraulic oil output from the operating valve 55 (operating valve 55A, operating valve 55B, operating valve 55C, operating valve 55D). It is a device.
The traveling oil passage 45 has a first traveling oil passage 45a, a second traveling oil passage 45b, a third traveling oil passage 45c, a fourth traveling oil passage 45d, and a fifth traveling oil passage 45e. The first traveling oil passage 45a is an oil passage connected to the pressure receiving portion 53a of the traveling pump 53L. The second traveling oil passage 45b is an oil passage connected to the pressure receiving portion 53b of the traveling pump 53L. The third traveling oil passage 45c is an oil passage connected to the pressure receiving portion 53a of the traveling pump 53R. The fourth traveling oil passage 45d is an oil passage connected to the pressure receiving portion 53b of the traveling pump 53R. The fifth traveling oil passage 45e is an oil passage connecting the operation valve 55, the first traveling oil passage 45a, the second traveling oil passage 45b, the third traveling oil passage 45c, and the fourth traveling oil passage 45d.

When the operating member 59 is swung forward (in the direction of arrow A1 in FIG. 1), the operating valve 55A is operated and the pilot pressure is output from the operating valve 55A. This pilot pressure acts on the pressure receiving portion 53a of the first traveling pump 53L via the first traveling oil passage 45a and acts on the pressure receiving portion 53a of the second traveling pump 53R via the third traveling oil passage 45c. As a result, the swash plate angles of the first traveling pump 53L and the second traveling pump 53R are changed, the first traveling motor 36L and the second traveling motor 36R rotate forward (forward rotation), and the work machine 1 moves straight forward. ..

Further, when the operation member 59 is swung backward (in the direction of arrow A2 in FIG. 1), the operation valve 55B is operated and the pilot pressure is output from the operation valve 55B. This pilot pressure acts on the pressure receiving portion 53b of the first traveling pump 53L via the second traveling oil passage 45b and also acts on the pressure receiving portion 53b of the second traveling pump 53R via the fourth traveling oil passage 45d. As a result, the swash plate angles of the first traveling pump 53L and the second traveling pump 53R are changed, the first traveling motor 36L and the second traveling motor 36R are reversed (reverse rotation), and the working machine 1 moves straight backward.

Further, when the operating member 59 is swung to the right (in the direction of arrow A3 in FIG. 1), the operating valve 55C is operated and the pilot pressure is output from the operating valve 55C. This pilot pressure acts on the pressure receiving portion 53a of the first traveling pump 53L via the first traveling oil passage 45a and acts on the pressure receiving portion 53b of the second traveling pump 53R via the fourth traveling oil passage 45d. As a result, the swash plate angles of the first traveling pump 53L and the second traveling pump 53R are changed, the first traveling motor 36L rotates forward and the second traveling motor 36R reverses, and the working machine 1 turns to the right.

Further, when the operating member 59 is swung to the left (in the direction of arrow A4 in FIG. 1), the operating valve 55D is operated and the pilot pressure is output from the operating valve 55D. This pilot pressure acts on the pressure receiving portion 53a of the second traveling pump 53R via the third traveling oil passage 45c and also acts on the pressure receiving portion 53b of the first traveling pump 53L via the second traveling oil passage 45b. As a result, the swash plate angles of the first traveling pump 53L and the second traveling pump 53R are changed, the first traveling motor 36L reverses, the second traveling motor 36R rotates forward, and the working machine 1 turns to the left.

Further, when the operating member 59 is swung in an oblique direction, the rotation direction and rotation speed of the first traveling motor 36L and the second traveling motor 36R are increased by the differential pressure of the pilot pressure acting on the pressure receiving portion 53a and the pressure receiving portion 53b. Determined, the working machine 1 makes a right turn or a left turn while moving forward or backward.
That is, when the operation member 59 is swung diagonally forward to the left, the work machine 1 turns left while advancing at a speed corresponding to the swing angle of the operating member 59, and when the operating member 59 is swung diagonally forward to the right, the operation member 59 is swung forward. When the working machine 1 turns to the right while advancing at a speed corresponding to the swing angle of the operating member 59 and the operating member 59 is swung diagonally backward to the left, the working machine 1 is swung diagonally backward to the left at a speed corresponding to the swing angle of the operating member 59. When 1 turns left while moving backward and swings the operating member 59 diagonally backward to the right, the working machine 1 turns right while moving backward at a speed corresponding to the swing angle of the operating member 59.

By the way, the accelerator 65 for setting the target rotation speed of the prime mover 32 is connected to the control device 60. The accelerator 65 is provided in the vicinity of the driver's seat 8. The accelerator 65 includes an accelerator lever that is swingably supported, an accelerator pedal that is swingably supported, an accelerator volume that is rotatably supported, an accelerator slider that is slidably supported, and the like. The accelerator 65 is not limited to the above-mentioned example. Further, a rotation detection device 66 for detecting the actual rotation speed of the prime mover 32 is connected to the control device 60. The rotation detection device 66 allows the control device 60 to grasp the actual rotation speed of the prime mover 32. The control device 60 sets a target rotation speed based on the operation amount of the accelerator 65, and controls the actual rotation speed so as to reach the set target rotation speed.

Now, when the control device 60 switches the travel switching valve 34 from the first state (first speed) to the second state (second speed), that is, the rotation speed of the travel motor is changed from the first speed to the second speed. When speeding up, shock reduction control is performed.
As shown in FIG. 1, the control device 60 reduces the shift shock by controlling the opening degree of the actuating valve 69 in the shock reduction control. The actuating valve 69 is connected to a section 40a which is a discharge oil passage 40 after branching and reaches the traveling operation device 54, that is, on the upstream side of the operation valve 55. The operating valve 69 may be connected to the traveling oil passage 45 on the downstream side of the operating valve 55.

The operating valve 69 is an electromagnetic proportional valve (proportional valve), and its opening degree can be changed by a control signal output from the control device 60. The control signal is, for example, a voltage, a current, or the like. The actuating valve 69 is a valve in which the opening degree increases as the control signal (voltage, current) output from the control device 60 increases, and the opening degree decreases as the control signal (voltage, current) decreases.
That is, the control device 60 reduces the opening degree of the operating valve 69 by changing the control signal output to the operating valve 69 in the shock reduction control.

In performing shock reduction control, the control device 60 sets the amount of decrease in the opening degree of the actuating valve 69 based on the straightness degree (straightness degree) of the work machine 1 (machine 2). The degree of straightness can be determined by the pressure of the hydraulic oil in the traveling oil passage 45.
As shown in FIG. 1, a pressure detection device 48 for detecting the pressure (pilot pressure) of the hydraulic oil in the traveling oil passage 45 is connected to the traveling oil passage 45. The pressure detection device 48 includes a first pressure detection device 48a, a second pressure detection device 48b, a third pressure detection device 48c, and a fourth pressure detection device 48d. The first pressure detection device 48a, the second pressure detection device 48b, the third pressure detection device 48c, and the fourth pressure detection device 48d are connected to the control device 60.

The first pressure detection device 48a is a sensor capable of detecting the first pilot pressure lf (t), which is the pressure of the hydraulic oil in the first running oil passage 45a. The second pressure detection device 48b is a sensor capable of detecting the second pilot pressure lb (t), which is the pressure of the hydraulic oil in the second running oil passage 45b. The third pressure detection device 48c is a sensor capable of detecting the third pilot pressure rf (t), which is the pressure of the hydraulic oil in the third running oil passage 45c. The fourth pressure detection device 48d is a fourth pressure detection device 48d capable of detecting the fourth pilot pressure rb (t), which is the pressure of the hydraulic oil in the fourth running oil passage 45d.

As shown in the equations (1) and (2), the control device 60 has a first pilot pressure lf (t), a second pilot pressure lb (t), a third pilot pressure rf (t), and a fourth pilot pressure. Based on rb (t), the degree of straightness S _Bratio (t) is obtained, and the degree of straightness S _Fratio (t) is obtained. When the ratio (rf (t) / lf (t)) is not within the predetermined range, the control device 60 uses the larger of the first pilot pressure lf (t) and the third pilot rf (t) as the first. The straight value is Pv _Bpivot . When the ratio (rb (t) / lb (t)) is not within the predetermined range, the control device 60 sets the larger of the second pilot lb (t) and the fourth pilot rb (t) as the second straight-ahead constant value Pv. Let's call it _Fpivot .

The control device 60 determines whether or not the vehicle is going straight based on the degree of straightness S _Bratio (t) and the degree of straightness S _Fratio (t). For example, when the straightness degree S _Bratio (t) or the straightness degree S _Fratio (t) exceeds 1.0 and is very large, the control device 60 determines that the work machine 1 (machine 2) is going straight. .. When the degree of straightness S _Bratio (t) or the degree of straightness S _Fratio (t) is less than 1.0 and is as close to zero as possible, the control device 60 determines that the turn is a turning point.

Hereinafter, for convenience of explanation, the straightness degree S _Bratio (t) and the straightness degree S _Fratio (t) are simply referred to as "straightness degree SV".
Hereinafter, the shock reduction control at the time of speed increase will be described in detail.
As shown in FIG. 2, in performing the shock reduction control, the control device 60 sets the reduction amount ΔF11 of the control signal in the shock reduction control based on the straightness degree SV. For example, the control device 60 increases the decrease amount ΔF11 as the straightness degree SV increases, and decreases the decrease amount ΔF11 as the straightness degree SV decreases. In other words, the control device 60 increases the decrease amount ΔF11 when the straightness degree SV is large and is close to straightness, and decreases the decrease amount ΔF11 when the straightness degree SV is small and is close to the turning point.

FIG. 3 is a diagram showing the relationship between the control values of the control signal [reduction values W24a, W24b, W24c and the switching of the traveling motor in the case of performing shock reduction control at the time of speed increase.
In the control device 60, the changeover switch (changeover SW) 61 is operated at the time point Q11, and the control device 60 changes the speed from the first state (first speed) to the second state (second speed) (2). It is assumed that the speed command) is acquired. When the control device 60 acquires the second speed command, the straightness SV is calculated, and the decrease amount ΔF11 is set from the calculated straightness SV.

As shown in FIG. 3, for example, at the time point Q11, when the straightness degree SV is large and close to straightness, the control device 60 is set to the reduction amount ΔF11a. Alternatively, the control device 60 sets the reduction amount ΔF11b at the time point Q11 when the degree of straightness SV is smaller than that of straightness and is slightly closer to the turning point. Alternatively, the control device 60 sets the reduction amount ΔF11c when the straightness degree SV is very small and is close to the turning point at the time point Q11.

In this way, the control device 60 sets the reduction amount ΔF11 (ΔF11a, ΔF11b, ΔF11c) according to the straightness degree SV at the time point Q11.
When the reduction amount ΔF11 is set, the control device 60 subtracts the reduction amount ΔF11 (ΔF11a, ΔF11b, ΔF11c) from the control value (current control value) W22a of the control signal immediately before the reduction in the shock reduction control. The reduction values are set to W24a, 24b, 24c. For example, the control device 60 sets the value W24a, which is obtained by subtracting the reduction amount ΔF11a from the current control value W22, as the reduction value. Alternatively, the control device 60 sets the value W24b, which is obtained by subtracting the reduction amount ΔF11b from the current control value W22a, as the reduction value. Alternatively, the control device 60 sets the value W24c, which is obtained by subtracting the reduction amount ΔF11b from the current control value W22a, as the reduction value.

When the reduction values W24a, W24b, and W24c are set, the control device 60 reduces the control value output to the operating valve 69 until the reduction values W24a, W24b, and W24c are reached.
Specifically, at the time point Q11, when the traveling of the aircraft 2 is close to straight ahead, the control device 60 sets the control device 60.
As shown in line W31a, the control value is lowered toward the reduction value W24a. As shown in the line W31a, when the reduction value W24a is reached at the time point Q12a, the control device 60 outputs a signal for exciting the solenoid of the traveling switching valve 34 to put the traveling switching valve (switching valve) 34 into the first state. Switch from (first speed) to the second state (second speed). Further, after the time point Q12a, as shown in the line W31a, the control value W22 before the reduction is restored.

Alternatively, at the time point Q11, when the traveling of the aircraft 2 is slightly closer to the turning point than the straight traveling, the control device 60 lowers the control value toward the reduced value W24b as shown in the line W31b. As shown in the line W31b, when the reduction value W24b is reached at the time point Q12b, the control device 60 outputs a signal for exciting the solenoid of the traveling switching valve 34 to put the traveling switching valve (switching valve) 34 into the first state. Switch from (first speed) to the second state (second speed). Further, after the time point Q12b, as shown in the line W31b, the control value W22 before the reduction is restored.

Alternatively, at the time point Q11, when the traveling of the aircraft 2 is close to the turning point, the control device 60 lowers the control value toward the reduced value W24c as shown in the line W31c. As shown in the line W31c, when the reduction value W24c is reached at the time point Q12c, the control device 60 outputs a signal for exciting the solenoid of the traveling switching valve 34 to put the traveling switching valve (switching valve) 34 into the first state. Switch from (first speed) to the second state (second speed). Further, after the time point Q12c, as shown in the line W31b, the control value W22 before the reduction is restored.

By the way, the reduction intervals Ta, Tb, Tc from the time point Q11, which is the starting point for lowering the control value of the control signal, to the time points Q12a, Q12b, Q12c, which is the end point for lowering the control value of the control signal, that is, the control value of the control signal. Focusing on the reduction sections Ta, Tb, and Tc until the reduction values W24a, W24b, and W24c are reached, the control device 60 keeps the first reduction speed of the control value constant. That is, in the reduction sections Ta, Tb, and Tc, the control device 60 keeps the inclinations of the lines W31a, W31b, and W31c constant.

Further, since the traveling switching valve 34 is switched between the second state and the first state at each of the time points Q12a, Q12b, and Q12c, the control device 60 switches the traveling switching valve 34 from the first state according to the straightness degree SV. The timing for switching to the second state is set to be different.
In the above-described embodiment, in each of the reduction sections Ta, Tb, and Tc, the rate of decrease in the control value (opening) of the control signal is uniformly constant from the start point to the end point of the reduction sections Ta, Tb, and Tc. , You may change the rate of decline on the way.

FIG. 4 shows a modified example in which the reduction speed of the control value of the control signal is changed in the middle in the reduction section Ta.
When the control device 60 acquires the 1st speed command and calculates the reduction value W24a based on the straightness degree SV, as shown in FIG. 4, the control device 60 controls the section (first section) Ta1 from the start point to the middle of the reduction section Ta. The decrease rate of the value is set to the second decrease rate, and the decrease rate of the control value of the section (second section) Ta2 from the middle to the end point is set to the third decrease rate. That is, the control device 60 sets the second reduction speed in the first section Ta1 by the inclination of the line W31a1 in the line W31a showing the control value in the reduction section Ta, and sets the third reduction speed in the second section Ta2 in the line W31a2. Set by tilt. The control device 60 sets the second lowering speed (inclination of the line W31a1) to be larger than the third lowering speed (inclination of the line W31a2).

Although the line W31a is described in the modified example, the second lowering speed and the third lowering speed may be set for the other lines W31b and 11c as well as the line W31a. In this case, the reduction value W24a is the reduction value W24b, 24c, the reduction section Ta is the reduction section Tb, Tc, the line W31a is the line W31b, W31c, the line W31a1 is the line W31b1, the line W31c1, the line W31a2 is the line W31b2, the line W31c2, The first section Ta1 may be read as the first section Tb1, Tc1, and the second section Ta2 may be read as the second section Tb2, Tc2.

In the above-described embodiment, the traveling operation device 54 is a hydraulic type in which the pilot pressure acting on the traveling pumps (first traveling pump 53L, second traveling pump 53R) is changed by the operation valve 55, which is shown in FIG. As described above, the traveling operation device 54 may be an electrically operated device.
As shown in FIG. 3, the traveling operation device 54 is an operation valve 55 (operation valves 55A, 55B, 55C) composed of an operation member 59 that swings in the left-right direction (machine width direction) or the front-rear direction and an electromagnetic proportional valve. , 55D). The control device 60 is connected to an operation detection sensor that detects the operation amount and operation direction of the operation member 59. The control device 60 controls the operation valves 55 (operation valves 55A, 55B, 55C, 55D) based on the operation amount and the operation direction detected by the operation detection sensor.

When the operating member 59 is operated forward (in the A1 direction, see FIG. 1), the control device 60 outputs a control signal to the operating valve 55A and the operating valve 55C, and the first traveling pump 53L and the second traveling pump 53R. Swing the swash plate in the direction of forward rotation (forward).
When the operating member 59 is operated rearward (A2 direction, see FIG. 1), the control device 60 outputs a control signal to the operating valve 55B and the operating valve 55D, and the first traveling pump 53L and the second traveling pump 53R. Swing the swash plate in the reverse (reverse) direction.

When the operation member 59 is operated to the right (A3 direction, see FIG. 1), the control device 60 outputs a control signal to the operation valve 55A and the operation valve 55D, and rotates the swash plate of the first traveling pump 53L in the normal direction. The swash plate of the second traveling pump 53R is swung in the reverse direction.
When the operation member 59 is operated to the left (A4 direction, see FIG. 1), the control device 60 outputs a control signal to the operation valve 55B and the operation valve 55C, and reverses the swash plate of the first traveling pump 53L. Swing in the direction, and swing the swash plate of the second traveling pump 53R in the direction of forward rotation.

The working machine 1 can be rotated by the prime mover 32, the traveling pumps 53L and 53R operated by the power of the prime mover 32 and discharged the hydraulic oil, and the hydraulic oil discharged by the traveling pumps 53L and 53R, and has a rotation speed of the second. The traveling motors 36L and 36R capable of switching between the first speed and the second speed higher than the first speed, the machine 2 provided with the prime mover 32, the traveling pumps 53L and 53R and the traveling motors 36L and 36R, and the traveling motor 36L. Depending on the operation of the traveling switching valve 34 and the operating member 59, which can switch between the first state in which the rotation speed of the 36R is set to the first speed and the second state in which the rotation speed of the traveling motors 36L and 36R is set to the second speed. A traveling operation device 54 having an operating valve 55 capable of changing the pressure of hydraulic oil acting on the traveling pumps 53L and 53R, and an operating valve 55 connected to the operating valve 55 on the upstream side or the downstream side of the operating valve 55. Control to perform shock reduction control to reduce the opening degree of the operating valve 69 by outputting a control signal to the operating valve 69 that can control the hydraulic oil flowing to the operating valve 69 and the operating valve 69 when switching from the first state to the second state. The device 60 is provided, and the control device 60 sets the amount of decrease in the opening degree of the operating valve 69 based on the degree of straightness of the machine body 2.

According to this, since the degree of straightness of the machine 2 is determined by the direction in which the driver (operator) operates the operation member 59 of the traveling operation device 54, the degree of straightness of the machine 2, that is, the operation of the driver (operator) By reducing the opening degree of the actuating valve 69 in accordance with the above, the speed can be increased (switched from the first state to the second state) while reducing the shift shock as intended. In other words, when the pressure acting on the operation valve 55 is changed by reducing the opening degree of the operation valve 69 in order to reduce the shift shock, the operation output from the operation valve 55 toward the traveling pumps 53L and 53R. Since the balance between the oil pressure and the degree of straightness of the actually traveling machine 2 (operation of the driver (operator)) can be matched, shifting is performed while suppressing the wobbling of the work machine 1 by the shock reduction control. It is possible to reduce the shock.

The actuating valve 69 is a valve in which the opening degree increases as the control value corresponding to the control signal increases and the opening degree decreases as the control value decreases. Based on this, the reduction amount ΔF11 of the control value is set as the reduction amount of the opening degree of the actuating valve 69, and the reduction values W24a, W24b, and W24c in the shock reduction control are calculated based on the reduction amount ΔF11.

According to this, since the reduction values W24a, W24b, and W24c of the control value of the control signal output to the operating valve 69 can be set according to the degree of straightness of the machine body 2, the shift shock can be reduced more smoothly.
The control device 60 keeps the first reduction rate of the control value from the start point to the end point of the reduction sections Ta, Tb, Tc constant in the reduction sections Ta, Tb, and Tc until the control values reach the reduction values W24a, W24b, and W24c. To.

According to this, since the pressure of the hydraulic oil acting on the traveling pumps 53L and 53R can be reduced as smoothly as possible, the shift shock can be smoothly reduced without discomfort.
The control device 60 controls from the start point of the reduction section Ta, Tb, Tc to the middle of the reduction section Ta, Tb, Tc in the reduction section Ta, Tb, Tc until the control value reaches the reduction value W24a, W24b, W24c. The second decrease rate of the value is made larger than the third decrease rate of the control value from the middle to the end point of the reduction sections Ta, Tb, and Tc.

According to this, the responsiveness of the actuated valve 69 can be improved in the shock reduction control.
The control device 60 changes the timing when the traveling switching valve 34 is switched from the first state to the second state according to the degree of straightness.
According to this, it is possible to change the timing of speed increase when the machine body 2 is traveling straight and when the machine body 2 is turning, and the workability can be further improved.

The control device 60 sets a large reduction amount ΔF11 when the straightness degree is large, and sets a small reduction amount ΔF11 when the straightness degree is small.
According to this, for example, when the airframe 2 is traveling straight, by increasing the amount of decrease ΔF11, it is possible to further reduce the shift shock at the time of speed increase in straight travel, and the aircraft 2 can turn straight from straight ahead. By reducing the amount of decrease ΔF11, the pressure difference (differential pressure) of the hydraulic oil acting on the forward or reverse rotation side of the traveling pumps 53L and 53R can be maintained. It is possible to stably reduce the shift shock while keeping it.

The working machine 1 includes a first traveling device 5 provided on the left side of the machine body 2 and a second traveling device 5 provided on the right side of the machine body 2, and the traveling motors 36L and 36R are the first traveling device 5. It is a second traveling motor that transmits traveling power to the first traveling motor and the second traveling device 5, and the traveling pumps 53L and 53R can operate the first traveling motor and the second traveling motor. The traveling switching valve 34 can switch between the first traveling motor and the second traveling motor between the first speed and the second speed.

According to this, in the working machine 1 provided with the first traveling device 5 provided on the left side of the machine body 2 and the second traveling device 5 provided on the right side of the machine body 2, the shift shock can be reduced more smoothly. It can be carried out.
It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The traveling switching valve 34 is a valve that can switch between the first state in which the traveling motor (first traveling motor 36L, second traveling motor 36R) is set to the first speed and the second state in which the traveling motor is set to the second speed. Often, it may be a proportional valve different from the directional control valve.
The traveling motor may be a motor having neutrality between the first speed and the second speed.

The traveling motor (first traveling motor 36L, second traveling motor 36R) may be an axial piston motor or a radial piston motor. When the traveling motor is a radial piston motor, it is possible to switch to the first speed by increasing the motor capacity, and it is possible to switch to the second speed by reducing the motor capacity.

1: Working machine 2: Machine 5: Traveling device 32: Motor 34: Traveling switching valve 36L: First traveling motor 36R: Second traveling motor 53L: First traveling pump 53R: Second traveling pump 54: Traveling operation device 55: Operation valve 55A: Operation valve 55B: Operation valve 55C: Operation valve 55D: Operation valve 59: Operation member 60: Control device 69: Operation valve

Claims (7)

The prime mover and
A traveling pump that is powered by a prime mover and discharges hydraulic oil,
A traveling motor that can rotate by the hydraulic oil discharged by the traveling pump and can switch between a first speed and a second speed whose rotation speed is higher than the first speed.
An airframe provided with the prime mover, a traveling pump, and a traveling motor, and
A traveling switching valve capable of switching between a first state in which the rotation speed of the traveling motor is set to the first speed and a second state in which the rotation speed of the traveling motor is set to the second speed.
A traveling operation device having an operation valve capable of changing the pressure of the hydraulic oil acting on the traveling pump according to the operation of the operating member, and a traveling operating device.
An operating valve that is connected to the operating valve on the upstream side or the downstream side of the operating valve and can control the hydraulic oil flowing through the operating valve.
A control device that performs shock reduction control that reduces the opening degree of the actuated valve by outputting a control signal to the actuated valve when switching from the first state to the second state.
Equipped with
The control device is a working machine that sets a decrease in the opening degree of the operating valve based on the degree of straightness of the machine. The actuated valve is a valve in which the opening degree increases as the control value corresponding to the control signal increases, and the opening degree decreases as the control value decreases.
The control device sets the amount of decrease in the control value as the amount of decrease in the opening degree of the actuated valve based on the degree of straightness of the machine, and calculates the decrease value in the shock reduction control based on the amount of decrease. The working machine according to claim 1. The working machine according to claim 2, wherein the control device keeps the first reduction rate of the control value from the start point to the end point of the reduction section constant in the reduction section until the control value reaches the reduction value. In the reduction section until the control value reaches the reduction value, the control device sets the second reduction rate of the control value from the start point of the reduction section to the middle of the reduction section from the middle to the end point of the reduction section. The working machine according to claim 2, wherein the control value is made larger than the third reduction speed. The working machine according to any one of claims 1 to 4, wherein the control device changes the timing when the traveling switching valve is switched from the first state to the second state according to the degree of straightness. The working machine according to any one of claims 1 to 4, wherein the control device sets a large amount of decrease when the degree of straightness is small, and sets a small amount of decrease when the degree of straightness is small. The first traveling device provided on the left side of the aircraft and
The second traveling device provided on the right side of the aircraft and
Equipped with
The traveling motor is a first traveling motor that transmits traveling power to the first traveling device and a second traveling motor that transmits traveling power to the second traveling device.
The traveling pump can operate the first traveling motor and the second traveling motor.
The working machine according to any one of claims 1 to 6, wherein the traveling switching valve is capable of switching between the first traveling motor and the second traveling motor between the first speed and the second speed.

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