JP2010059849A - Travel device for wheel type construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce operation speed of a servo cylinder of a capacity control device without causing getting stuck of contamination and without increasing capacity of a large diameter chamber of the capacity control device when the capacity of a variable capacity hydraulic motor is shifted from a small capacity to a large capacity. <P>SOLUTION: This device includes a swash plate control mechanism 10 controlling the capacity of a swash plate type hydraulic motor 7 driving a tire 1, the servo cylinder 11, the large diameter chamber 13 disposed at one end of the servo cylinder 11, connected to a control pressure supply conduit 12, and given with a control pressure introduced by the control pressure supply conduit 12, and a small diameter chamber 15 disposed at another end of the servo cylinder 11, connected to a high pressure supply conduit 14, and given with a high pressure introduced by the high pressure supply conduit 14. The device is provided with a restriction 17 which is a first restriction disposed in the control pressure supply conduit 12, a connection conduit 18 providing communication between the large diameter chamber 13 and the small diameter chamber 15, and a restriction 19 which is a second restriction disposed in the connection conduit 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a traveling device for a wheel-type construction machine, which is provided in a wheel-type construction machine such as a wheel loader and has a variable displacement hydraulic motor that drives a tire and a displacement control device that controls the displacement of the variable displacement hydraulic motor. .

  FIG. 7 is a hydraulic circuit diagram showing a main configuration of a traveling device for a conventional wheel type construction machine. This prior art is provided in a wheel type construction machine such as a wheel loader. A variable capacity hydraulic motor such as a swash plate type hydraulic motor 7 for driving a tire (not shown) provided in the wheel loader and the swash plate type hydraulic motor 7 It has a capacity control device for controlling capacity, that is, a swash plate control mechanism 10.

  The swash plate type hydraulic motor 7 is operated by pressure oil supplied and discharged via the main pipe lines 8 and 9, and the drive shaft 26 rotates. The rotational force of the drive shaft 26 is transmitted as a rotational force to a tire (not shown).

  The swash plate control mechanism 10 is connected to a servo cylinder 11 and one end of the servo cylinder 11 and connected to a control pressure supply pipe 12. Pressure oil guided by the control pressure supply pipe 12, that is, control pressure is A large-diameter portion 13 to be provided, and a small-diameter chamber 15 disposed at the other end of the servo cylinder 11 and connected to a high-pressure supply line 14 and to which high-pressure oil guided by the high-pressure supply line 14 is supplied. ing. The control pressure supply pipe 12 is provided with a throttle 17 for adjusting the control pressure. The large-diameter chamber 13 of the swash plate hydraulic motor 7 and the swash plate control mechanism 10 is connected to a tank via a drain line 16.

In this prior art, high-pressure oil is constantly supplied to the small-diameter chamber 15 of the swash plate control mechanism 10 via the high-pressure supply line 14. In this state, when a control pressure equivalent to the pressure of the small-diameter chamber 15 is supplied to the large-diameter chamber 13 via the control-pressure supply pipe 12, due to the difference in pressure receiving area between the large-diameter chamber 13 and the small-diameter chamber 15, The servo cylinder 11 moves to the left in FIG. As a result, the tilt of the swash plate hydraulic motor 7 becomes the minimum tilt, the rotational speed of the drive shaft 26 increases, and high-speed running is performed. Further, when the control pressure of the control pressure supply pipe 12 is reduced from the state where the high-speed running is performed in this manner, the servo cylinder is caused by the pressure of the pressure oil applied to the small diameter chamber 15 through the high pressure supply pipe 14. 12 moves to the right in FIG. Thereby, the inclination of the swash plate type hydraulic motor 7 becomes the maximum inclination, and the rotational speed of the drive shaft 26 is reduced, and the low-speed traveling is performed. A known technique of this type is disclosed in Patent Document 1.
JP 2002-130145 A

  In the prior art described above, the response speed of the swash plate type hydraulic motor 7 at the time of transition from small tilt to large tilt of the swash plate hydraulic motor 7 for shifting from high speed travel to low speed travel, that is, a swash plate control mechanism. There is a desire to reduce the operating speed of the ten servo cylinders 11 depending on the type of work performed by the wheel loader. That is, there is a demand for a gradual transition from high speed travel to low speed travel. The operating speed of the swash plate control mechanism 10 at this time is the size of the opening area of the throttle 17 provided in the control pressure supply pipe 12 or the volume of the large-diameter chamber 13 to which the control pressure supply pipe 12 is connected. Depends on the size.

  Therefore, in order to slow down the operating speed of the swash plate control mechanism 10, for example, it is conceivable to set the aperture area of the diaphragm 17 small. However, if the opening area of the restrictor 17 is made too small, contamination such as metal powder contained in the pressure oil flowing through the control pressure supply pipe 12 is generated. For this reason, there is a limit to reducing the aperture area of the diaphragm 17. In addition, when contamination clogging arises, the malfunction of the swash plate control mechanism 10 will be caused.

  In order to slow down the operating speed of the swash plate control mechanism 10, the volume of the large-diameter chamber 13 of the swash plate control mechanism 10 is increased and the large-diameter chamber 13 is discharged to the control pressure supply pipe 12. It is conceivable to increase the time until the servo cylinder 11 reaches the stroke end by increasing the flow rate of the pressure oil. However, when the volume of the large-diameter chamber 13 is increased in this way, the shape and size of the swash plate control mechanism 10 is increased, leading to an increase in the size of the traveling device provided with the swash plate control mechanism 10.

  The present invention has been made from the actual situation in the above-described prior art, and its purpose is to prevent the occurrence of contamination clogging when the capacity of a variable displacement hydraulic motor is shifted from a small capacity to a large capacity, and to a capacity control device. An object of the present invention is to provide a traveling device for a wheel type construction machine that can reduce the operating speed of a servo cylinder of the capacity control device without increasing the volume of the large-diameter chamber.

  In order to achieve this object, a traveling device for a wheel-type construction machine according to the present invention is provided in a wheel-type construction machine having a traveling body having a tire, and a variable displacement hydraulic motor for driving the tire, and the variable displacement hydraulic motor. A displacement control device for controlling the displacement of the displacement hydraulic motor, and the displacement control device is arranged at one end of the servo cylinder and connected to a control pressure supply line, and the control pressure supply line Wheel-type construction having a large-diameter chamber to which a control pressure is introduced and a small-diameter chamber that is disposed at the other end of the servo cylinder and is connected to a high-pressure supply line and to which a high pressure is introduced by the high-pressure supply line In the machine travel device, a first throttle provided in the control pressure supply line, a connection line for communicating the large-diameter chamber and the small-diameter chamber, and a connection line provided in the connection line It is characterized in that a second aperture.

  In the present invention configured as described above, when the control pressure of the control pressure supply line is made smaller than before from the state where the displacement of the variable displacement hydraulic motor is controlled to be small and high-speed running is being performed, The servo cylinder operates in the direction of the large-diameter chamber due to the high pressure led to the small-diameter chamber of the capacity control device via the supply pipe, and the pressure oil in the large-diameter chamber is discharged through the control pressure supply pipe and the first throttle. Is done. At this time, a part of the pressure oil guided by the high-pressure supply pipe is led to the large-diameter chamber of the capacity control device through the connection pipe and the second throttle. Through such an operation, the capacity of the variable displacement hydraulic motor is increased, the rotational speed of the variable displacement hydraulic motor is decreased, and the rotational force is transmitted to the tire to shift to low speed traveling.

  Therefore, for example, if the aperture areas of the first aperture and the second aperture are set to the minimum aperture areas that do not cause contamination clogging, the two apertures of the first aperture and the second aperture become resistances. The operating speed of the servo cylinder at that time can be made slower than when the throttle is provided only in the control pressure supply line. In addition, the connection pipe line and the small diameter chamber communicating with the large diameter chamber of the capacity control device are part of the large diameter chamber in appearance, and the apparent volume of the large diameter chamber is the same as the case where no connection pipe is provided. It can be made larger than the volume of the large-diameter chamber. As a result, the amount of pressure oil discharged from the large-diameter chamber can be increased, the time until the servo cylinder reaches the stroke end can be lengthened, and the operating speed of the servo cylinder at this time can be reduced. it can.

  That is, according to the present invention, when the capacity of the variable displacement hydraulic motor is shifted from the small capacity to the large capacity, this capacity is prevented without causing contamination and without increasing the capacity of the large diameter chamber of the capacity control device. The operating speed of the servo cylinder of the control device can be slowed down, and the response speed of the variable displacement hydraulic motor can be slowed down.

  Further, according to the present invention, in the wheel-type construction machine, the variable displacement hydraulic motor includes a swash plate, a plurality of pistons each having a shoe slidably contacting the swash plate, and the pistons are fitted and reciprocated. A cylinder block that rotates with movement, a housing in which the swash plate, the piston, and the cylinder block are housed, and a drive shaft that rotates integrally with the cylinder block and transmits a rotational force to the tire. And the capacity control device is provided in the housing and includes a swash plate control mechanism for controlling the tilt of the swash plate. The present invention configured as described above can be effectively used for a wheel type construction machine that drives a tire by a swash plate type hydraulic motor.

  Further, the present invention is characterized in that in the wheel type construction machine, the connection pipe line, the first throttle, and the second throttle are provided in the housing. The present invention configured as described above provides a compact travel without increasing the number of pipes and hoses because the connecting pipe, the first throttle, and the second throttle are provided in the housing provided with the swash plate control mechanism. It can be a device.

  Further, according to the present invention, in the wheel type construction machine, the variable displacement hydraulic motor forms a swingable valve plate, a cylinder block that is slidably contacted with the valve plate, and a central axis of the cylinder block. A center rod, a plurality of pistons fitted into the cylinder block, a part of the valve plate, the cylinder block, the center rod, a casing in which the piston is accommodated, and each of the center rod and the piston A slanted shaft type hydraulic motor having a disk drive connected to and rotating with the rotation of the cylinder block and transmitting a rotational force to the tire, the capacity control device being connected to the casing, and the valve plate A slant axis control mechanism for controlling the swing of the valve plate, provided in a head sector in which a part of the valve plate is accommodated. It is. The present invention configured as described above can be effectively used for a wheel-type construction machine that drives a tire by an oblique axis hydraulic motor.

  Further, the present invention is characterized in that, in the wheel type construction machine, the connection pipe line, the first throttle, and the second throttle are provided in the head sector. According to the present invention configured as described above, since the connecting pipe, the first throttle, and the second throttle are provided in the head sector in which the oblique axis control mechanism is provided, the compact traveling without increasing the number of pipes and hoses is achieved. It can be a device.

  According to the present invention, in the wheel type construction machine, the first throttle is provided in the head sector, and the connection pipe line and the second throttle are provided in the servo cylinder. According to the present invention configured as described above, the first throttle is provided in the head sector where the oblique axis control mechanism is provided, and the connecting pipe and the second restriction are provided in the servo cylinder of the oblique axis control mechanism. And a compact traveling device that does not increase the number of hoses.

  According to the present invention, in the wheel-type construction machine, the first throttle is provided in the head sector, the connection pipe line and the second throttle are accommodated in an outer peripheral surface of the servo cylinder and a servo cylinder. It is characterized by comprising a gap formed between the outer peripheral surface of the cylinder and the inner peripheral wall of the head sector facing the cylinder. According to the present invention configured as described above, the first diaphragm is provided in the head sector in which the oblique axis control mechanism is provided, and the gap between the outer peripheral surface of the servo cylinder of the oblique axis control mechanism and the inner peripheral wall of the head sector is Since the connection pipe line and the second throttle are formed, a travel device with a simpler structure that does not increase the number of pipes and hoses can be obtained.

  The present invention communicates a first throttle provided in a control pressure supply line connected to a large diameter chamber of a capacity control device that controls the capacity of a variable capacity hydraulic motor, and a large diameter chamber and a small diameter chamber of the capacity control device. And a second throttle provided in the connection line, so that when the capacity of the variable displacement hydraulic motor is shifted from a small capacity to a large capacity, without causing clogging, Without increasing the volume of the large-diameter chamber of the capacity control device, the operating speed of the servo cylinder of the capacity control device can be reduced, and the response speed of the variable capacity hydraulic motor can be made slow. As a result, it is possible to prevent malfunction of the capacity control device due to contamination clogging, and to gradually shift from high speed traveling to low speed traveling while suppressing an increase in the size of the traveling device, thereby ensuring desirable traveling performance. .

  The best mode for carrying out a traveling device for a wheel type construction machine according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a wheel loader cited as an example of a wheel-type construction machine provided with the first embodiment of the traveling device according to the present invention, and FIG. 2 is a main part of the first embodiment of the traveling device according to the present invention. FIG. 3 is a cross-sectional view of a principal part showing a swash plate type hydraulic motor and a swash plate control mechanism provided in the first embodiment of the present invention.

  The wheel-type construction machine provided with the first embodiment of the traveling device according to the present invention is, for example, a wheel loader as shown in FIG. 1 and is disposed on the traveling body 2 including the tire 1 and the traveling body 2. A main body 4 including the cab 3 and a work tool 6 including a bucket 5 provided on the main body 4 so as to be rotatable in the vertical direction are provided.

  A first embodiment of the traveling device according to the present invention provided in such a wheel loader is, as shown in FIG. 2, a variable capacity hydraulic motor for driving a rear tire 1 provided in the wheel loader, for example, a swash plate type hydraulic pressure. The motor 7 and a capacity control device for controlling the capacity of the swash plate type hydraulic motor 7, that is, a swash plate control mechanism 10 are provided. As described above, the swash plate type hydraulic motor 7 is operated by the pressure oil supplied and discharged via the main pipelines 8 and 9, and the drive shaft 26 rotates. The rotational force of the drive shaft 26 is transmitted to the rear wheel tire 1 shown in FIG. 1 as rotational force.

  The swash plate control mechanism 10 is connected to a servo cylinder 11 and one end of the servo cylinder 11 and connected to a control pressure supply pipe 12. Pressure oil guided by the control pressure supply pipe 12, that is, control pressure is A large-diameter chamber 13 provided, and a small-diameter chamber 15 disposed at the other end of the servo cylinder 11 and connected to a high-pressure supply line 14 and to which high-pressure pressure oil guided by the high-pressure supply line 14 is supplied. ing. The control pressure supply line 12 is provided with a throttle 17 for adjusting the control pressure. The diaphragm 17 constitutes a first diaphragm. The large-diameter chamber 13 of the swash plate hydraulic motor 7 and the swash plate control mechanism 10 is connected to a tank (not shown) via a drain pipe 16. The above configuration is the same as that shown in FIG.

  The first embodiment includes a connection pipe 18 that allows the large-diameter chamber 13 and the small-diameter chamber 15 of the swash plate control mechanism 10 to communicate with each other, and a throttle 19 provided in the connection pipe 18. The diaphragm 19 constitutes a second diaphragm.

  As shown in FIG. 3, the swash plate type hydraulic motor 7 includes a housing 20 and a sub-hanging 21 provided integrally with the housing 20. In the housing 20, a swash plate 22 that is tilt-controlled by the servo cylinder 11 of the swash plate control mechanism 10, a plurality of pistons 24 each having a shoe 23 that is in sliding contact with the swash plate 22, and these pistons 24 are fitted. A cylinder block 25 that is inserted and rotated with the reciprocation of the piston 24 is accommodated. Moreover, the drive shaft 26 which rotates integrally with the cylinder block 25 and transmits a rotational force to the tire 1 of the rear wheel shown in FIG. 1 as described above is provided.

  In the sub-housing 21, a passage 27 communicating with the main pipeline 8 shown in FIG. 1 and a passage 28 communicating with the main pipeline 9 are formed. The sub-housing 21 is also formed with a main portion of the control pressure supply line 12 shown in FIG.

  Further, as shown in FIG. 3, in the vicinity of the swash plate control mechanism 10 in the housing 20, a connection pipe 18 described above, a throttle 17 as a first throttle provided in the control pressure supply pipe 12, and a connection A throttle 19 as a second throttle provided in the pipe 18, a part of the control pressure supply pipe 12, and a high pressure control pipe 14 are also provided. Note that the connection pipe line 18 communicates with the high-pressure supply pipe line 14 through, for example, the small-diameter chamber 15.

  In the first embodiment configured as described above, as described above, high-pressure oil is always supplied to the small-diameter chamber 15 of the swash plate control mechanism 10 via the high-pressure supply line 14. In this state, if a control pressure having the same size as the pressure of the small diameter chamber 15 is supplied to the large diameter chamber 13 via the control pressure supply pipe 12, the difference in pressure receiving area between the large diameter chamber 13 and the small diameter chamber 15 is caused. The servo cylinder 11 moves to the left in FIG. 1 and to the right in FIG. Thereby, the inclination of the swash plate type hydraulic motor 7 becomes the minimum inclination. At this time, since the large-diameter chamber 13 and the small-diameter chamber 15 of the swash plate control mechanism 10 have the same pressure, no pressure oil flows through the connection pipe line 18. Accordingly, the servo cylinder 11 can be moved at a high operating speed without receiving resistance from the throttle 19 provided in the connection pipe 18. Thereby, the response speed when shifting the swash plate hydraulic motor 7 from the maximum tilt to the minimum tilt can be set to a relatively high response speed.

  During the tilt control as described above, for example, when pressure oil is supplied from the main pipeline 8 or the main pipeline 9 shown in FIG. 1 via the passage 27 or the passage 28 of the sub-housing 21, the piston 24 is connected to the cylinder block 25. The cylinder block 25 is rotated while the shoe 23 provided at the end of the piston 24 is in sliding contact with the swash plate 22. As the cylinder block 25 rotates, the drive shaft 26 rotates at a high rotational speed, and the rotational force of the drive shaft 26 is transmitted as the rotational force of the rear tire 1 shown in FIG. Is done.

  As described above, when the control pressure of the control pressure supply pipe 12 is made smaller than before from the state where the tilt of the swash plate type hydraulic motor 7 is controlled to the minimum tilt and the high speed running is performed, the high pressure supply pipe The force due to the high pressure guided through the passage 14 overcomes, the servo cylinder 11 operates in the direction of the large-diameter chamber 13, and the pressure oil in the large-diameter chamber 13 is discharged through the throttle 17 and the control pressure supply pipe 12. Is done. At this time, a part of the pressure oil guided by the high-pressure supply pipe 14 is guided to the large-diameter chamber 13 of the swash plate control mechanism 10 through the connection pipe 18 and the throttle 19. Through such an operation, the inclination of the swash plate hydraulic motor 7 becomes the maximum inclination, the rotational speed of the cylinder block 25 decreases, and the drive shaft 26 rotates at a low rotational speed. The rotational force of the drive shaft 26 is transmitted to the rear wheel tire 1 shown in FIG.

  Therefore, for example, if the opening areas of the diaphragms 17 and 19 are set to the minimum opening areas that do not cause contamination clogging, when the inclination of the swash plate hydraulic motor 7 is shifted from the minimum inclination to the maximum inclination, The two diaphragms of the diaphragm 17 and the diaphragm 19 serve as resistances, and the operating speed of the servo cylinder 11 at this time can be made slower than the case where the diaphragm 17 is provided only in the control pressure supply pipe 12. . At this time, the connecting pipe line 18 and the small-diameter chamber 15 communicating with the large-diameter chamber 13 of the swash plate type control mechanism 10 appear to be part of the large-diameter chamber, and the apparent volume of the large-diameter chamber is expressed as follows. The volume of the large-diameter chamber 13 when the connecting pipe 18 is not provided can be increased. As a result, the amount of pressure oil discharged from the large-diameter chamber 13 can be increased, and the time until the servo cylinder 11 reaches the stroke end can be lengthened. The operating speed of the servo cylinder 11 at this time can be increased. This can also be slow.

  According to the first embodiment configured as described above, when shifting the tilt of the swash plate hydraulic motor 7 from the minimum tilt to the maximum tilt, that is, when shifting from a small capacity to a large capacity, without causing contamination, Further, the operating speed of the servo cylinder 11 of the swash plate control mechanism 10 can be reduced without increasing the volume of the large-diameter chamber 13 of the swash plate control mechanism 10, and the response speed of the swash plate type hydraulic motor 7 is moderated. Can be. As a result, it is possible to prevent malfunction of the swash plate control mechanism 10 due to contamination clogging, and to gradually shift from high speed traveling to low speed traveling while suppressing an increase in the size of the traveling device according to the first embodiment, which is desirable. Driving performance can be ensured.

  Note that when the swash plate hydraulic motor 7 is shifted from the maximum tilt to the minimum tilt, the response speed of the swash plate hydraulic motor 7 is increased so that the travel performance can be quickly shifted from the low speed travel to the high speed travel. Can be maintained.

  In the first embodiment, the connecting pipe 18, the throttle 17 as the first throttle, and the throttle 19 as the second throttle are provided in the housing 20 in which the swash plate control mechanism 10 is provided. It can be a compact travel device that does not increase the number of hoses and hoses, does not affect the layout design for the equipment and equipment provided around the swash plate type hydraulic motor 7, and can reduce the production cost. And practical.

  FIG. 4 is a cross-sectional view of the main part showing the oblique axis hydraulic motor and the oblique axis control mechanism provided in the second embodiment of the present invention.

  This second embodiment is also provided, for example, in the wheel loader shown in FIG. 1, and the basic configuration is substantially the same as that shown in FIG. In the second embodiment, the variable displacement hydraulic motor that drives the tire 1 on the rear wheel of the wheel loader is composed of a slanted axis hydraulic motor 30 as shown in FIG.

  The oblique axis hydraulic motor 30 includes a casing 31 and a head sector 32 provided integrally with the casing 31. In the casing 31, there is a valve plate 33 that is controlled to swing by the servo cylinder 11 of the capacity control device, that is, the oblique axis control mechanism 39, a cylinder block 34 that is slidably contacted with the valve plate 33, and the cylinder block 34. A center rod 35 forming a central axis and a plurality of pistons 36 fitted into the cylinder block 34 are accommodated. Each of the center rod 35 and the piston 36 is connected, and rotates as the cylinder block 34 rotates, and a part of the disk drive 37 that transmits the rotational force to the tire 1 of the rear wheel loader shown in FIG. The casing 31 is accommodated.

  The head sector 32 connected to the casing 31 is provided with the oblique axis control mechanism 39 described above. The oblique axis control mechanism 39 has substantially the same configuration as the swash plate control mechanism 10 in the first embodiment. That is, the oblique axis control mechanism 39 is connected to the servo cylinder 11 that controls the swing of the valve plate 33 and the control pressure supply line 12 disposed at one end of the servo cylinder 11. 12 is connected to a high pressure supply line 14 which is disposed at the other end of the servo cylinder 11 and is connected to a high pressure supply line 14. And a small-diameter chamber 15 to which pressure oil is applied. The control pressure supply line 12 is provided with a first throttle for adjusting the control pressure, that is, a throttle 17.

  In the second embodiment, as in the first embodiment, the connecting pipe 18 that connects the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 and the first connecting pipe 18 are provided. Two stops, that is, a stop 19 is provided.

  In the second embodiment, as shown in FIG. 4, a connection line 18 and a restriction 19, a control pressure supply line 12 and a restriction 17, and a high pressure supply line 14 are provided in the head sector 32.

  The second embodiment configured as described above can obtain substantially the same operation and effect as in the first embodiment. That is, high-pressure oil is constantly supplied to the small-diameter chamber 15 of the oblique axis control mechanism 39 via the high-pressure supply line 14. In this state, if a control pressure having the same size as the pressure of the small diameter chamber 15 is supplied to the large diameter chamber 13 via the control pressure supply pipe 12, the difference in pressure receiving area between the large diameter chamber 13 and the small diameter chamber 15 is caused. The servo cylinder 11 moves upward in FIG. Thereby, the capacity | capacitance of the oblique-axis type hydraulic motor 30 becomes the minimum capacity. At this time, since the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 have the same pressure, no pressure oil flows through the connection pipe line 18. Accordingly, the servo cylinder 11 can be moved at a high operating speed without receiving resistance from the throttle 19 provided in the connection pipe 18. Thereby, the response speed when shifting the oblique axis hydraulic motor 30 from the maximum capacity to the minimum capacity can be set to a relatively fast response speed.

  During pressure control as described above, for example, when pressure oil is supplied from the main pipeline 8 or the main pipeline 9 shown in FIG. 1 through a passage formed in the head sector 32, the piston 36 reciprocates in the cylinder block 34. As a result, the cylinder block 34 rotates while slidingly contacting the valve plate 32. Along with the rotation of the cylinder block 34, the disk drive 37 rotates at a high rotational speed, and the rotational force of the disk drive 37 is transmitted as the rotational force of the tire 1 of the rear wheel shown in FIG. Is done.

  In this way, when the control pressure of the control pressure supply line 12 is made smaller than before from the state where the capacity of the oblique shaft type hydraulic motor 30 is controlled to the minimum capacity and the high speed running is performed, the high pressure supply line The force due to the high pressure guided through 14 is overcome, the servo cylinder 11 operates in the direction of the large-diameter chamber 13, and the pressure oil in the large-diameter chamber 13 is discharged via the throttle 17 and the control pressure supply pipe 12. The At this time, a part of the pressure oil guided by the high-pressure supply pipe 14 is guided to the large-diameter chamber 13 of the oblique axis control mechanism 39 through the connection pipe 18 and the throttle 19. Through such an operation, the capacity of the oblique axis hydraulic motor 30 becomes the maximum capacity, the rotational speed of the cylinder block 34 decreases, and the disk drive 37 rotates at a low rotational speed. The rotational force of the disk drive 37 is transmitted to the rear wheel tire 1 shown in FIG.

  Therefore, for example, if the opening areas of the throttles 17 and 19 are set to the minimum opening areas that do not cause contamination clogging, when the capacity of the oblique axis hydraulic motor 30 is shifted from the minimum capacity to the maximum capacity, the diaphragm 17 Further, the two throttles of the throttle 19 serve as resistances, and the operating speed of the servo cylinder 11 at this time can be made slower than the case where the throttle 17 is provided only in the control pressure supply pipe 12. At this time, the connecting pipe line 18 and the small-diameter chamber 15 communicating with the large-diameter chamber 13 of the oblique-axis control mechanism 30 appear to be part of the large-diameter chamber, and the apparent volume of the large-diameter chamber is reduced. The volume of the large-diameter chamber 13 when the connection pipe 18 is not provided can be increased. As a result, the amount of pressure oil discharged from the large-diameter chamber 13 can be increased, and the time until the servo cylinder 11 reaches the stroke end can be lengthened. The operating speed of the servo cylinder 11 at this time can be increased. This can also be slow.

  Similarly to the first embodiment, the second embodiment configured as described above does not cause contamination when the capacity of the oblique axis hydraulic motor 30 is shifted from the minimum capacity to the maximum capacity, and the oblique axis control is performed. Without increasing the volume of the large-diameter chamber 13 of the mechanism 39, the operating speed of the servo cylinder 11 of the inclined axis control mechanism 39 can be reduced, and the response speed of the inclined axis type hydraulic motor 30 can be reduced. it can. As a result, it is possible to prevent malfunction of the oblique axis control mechanism 39 due to contamination clogging, and to gradually shift from high speed running to low speed running while suppressing an increase in the size of the traveling device according to the second embodiment, which is desirable. Driving performance can be ensured.

  It should be noted that when the oblique axis hydraulic motor 30 is shifted from the maximum capacity to the minimum capacity, the response performance of the inclined axis hydraulic motor 30 is increased so that the traveling performance can be quickly shifted from the low speed traveling to the high speed traveling. Can be maintained.

  In the second embodiment, the connecting pipe 18, the diaphragm 17 as the first diaphragm, and the diaphragm 19 as the second diaphragm are provided in the head sector 32 where the oblique axis control mechanism 39 is provided. It can be a compact traveling device that does not increase the number of pipes and hoses, does not affect the layout design for the equipment and equipment provided around the oblique axis hydraulic motor 30, and suppresses the production cost. Can be practically used.

  FIG. 5 is a cross-sectional view of the main part showing the oblique axis hydraulic motor and the oblique axis control mechanism provided in the third embodiment of the present invention.

  In the third embodiment, similarly to the second embodiment shown in FIG. 4, the variable displacement hydraulic motor is composed of a slant shaft hydraulic motor 30, and the servo cylinder 11, An oblique axis control mechanism 39 including a large-diameter chamber 13 and a small-diameter chamber 15 is provided. In the third embodiment, the connecting pipe 18 that communicates the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 and the second throttle provided in the connecting pipe 18, that is, the throttle 19 is provided in the servo cylinder 11. It is provided along the virtual central axis. The control pressure supply pipe 12, the first throttle 17, and the high pressure supply pipe 14 are provided in the head sector 32. Other configurations are the same as those of the second embodiment.

  In the third embodiment, similarly to the second embodiment, the connecting pipe 18 that connects the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 and the throttle 19 provided in the connecting pipe 18 are provided. Therefore, as in the second embodiment, it is possible to prevent malfunction of the oblique axis control mechanism 39 due to contamination clogging, and to suppress the increase in size of the traveling device according to the third embodiment, and from low speed traveling to high speed. The vehicle can be gradually shifted to traveling, and desirable traveling performance can be ensured. Further, when the oblique axis hydraulic motor 30 is shifted from the maximum capacity to the minimum capacity, the response performance of the oblique axis hydraulic motor 30 is increased so that the traveling performance can be quickly shifted from the low speed traveling to the high speed traveling. Can be maintained.

  Further, since the connecting pipe 18 and the throttle 19 which is the second throttle are provided in the servo cylinder 11, a compact traveling device without increasing the number of pipes and hoses can be obtained. It does not affect the layout design of the equipment and equipment provided around 39, and the production cost can be suppressed, which is highly practical.

  FIG. 6 is a cross-sectional view of a principal part showing a slant axis hydraulic motor and a slant axis control mechanism provided in the fourth embodiment of the present invention.

  In the fourth embodiment, similarly to the second embodiment shown in FIG. 4, the variable displacement hydraulic motor is composed of the oblique axis hydraulic motor 30, and the head cylinder 32 provided integrally with the casing 31 includes the servo cylinder 11, An oblique axis control mechanism 39 including a large-diameter chamber 13 and a small-diameter chamber 15 is provided. In the fourth embodiment, the control pressure supply line 12, the first restriction 17, and the high pressure supply line 14 are provided in the head sector 32. In addition, a connecting pipe that communicates the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 and a second throttle provided in the connecting pipe include an outer peripheral surface of the servo cylinder 11 and the servo cylinder 11. Is formed by a gap 38 formed between the outer peripheral surface of the servo cylinder 11 and the inner peripheral wall of the head sector 32 facing the servo cylinder 11. Other configurations are the same as those of the second embodiment described above.

  In the fourth embodiment as well, a connecting pipe that communicates the large-diameter chamber 13 and the small-diameter chamber 15 of the oblique axis control mechanism 39 with the gap 38 and a second throttle provided in the connecting pipe are configured. For this reason, the same effect as the second embodiment can be obtained.

  Further, a first throttle provided in the control pressure supply pipe 12, that is, a throttle 17 is provided in the head sector 32, and the outer peripheral surface of the servo cylinder 11 of the oblique axis control mechanism 39 and the inner peripheral wall of the head sector 32 are provided. Since the connecting pipe line communicating with the large-diameter chamber 13 and the small-diameter chamber 15 and the second throttle are formed by the gap 38 formed therebetween, the traveling device having a simpler structure that does not increase the number of pipes and hoses. It is possible to reduce the production cost without affecting the arrangement design for the equipment and equipment around the oblique axis type hydraulic motor 39, which is highly practical.

  In the swash plate hydraulic motor 7 according to the first embodiment shown in FIGS. 1 to 3 described above, the housing 20 is provided with a connection pipe 18 and a throttle 19 as a second throttle. Instead of such a configuration, as in the third embodiment shown in FIG. 5, the servo cylinder 11 of the swash plate control mechanism 10 may be provided with a connecting pipe line 18 and a throttle 19. In addition, as in the fourth embodiment shown in FIG. 6, the connection pipe line and the second diaphragm are opposed to the outer peripheral surface of the servo cylinder 11 and the outer peripheral surface of the servo cylinder 11 in which the servo cylinder 11 is accommodated. It may be configured by a gap formed between the inner peripheral wall of the housing 20 to be formed.

It is a side view which shows the wheel loader mentioned as an example of the wheel type construction machine with which 1st Embodiment of the traveling apparatus which concerns on this invention is provided. 1 is a hydraulic circuit diagram showing a configuration of a main part of a first embodiment of a traveling device according to the present invention. It is principal part sectional drawing which shows the swash plate type hydraulic motor and swash plate control mechanism with which 1st Embodiment of this invention is equipped. It is principal part sectional drawing which shows the slant axis type hydraulic motor and slant axis control mechanism with which 2nd Embodiment of this invention is equipped. It is principal part sectional drawing which shows the slant axis type hydraulic motor and slant axis control mechanism with which 3rd Embodiment of this invention is equipped. It is principal part sectional drawing which shows the slant axis type hydraulic motor and slant axis control mechanism with which 4th Embodiment of this invention is equipped. It is a hydraulic circuit diagram which shows the principal part structure of the traveling apparatus of the conventional wheel type construction machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire 2 Traveling body 4 Main body 6 Work tool 7 Swash plate type hydraulic motor (variable capacity hydraulic motor)
10 Swash plate control mechanism (capacity control device)
11 Servo cylinder 12 Control pressure supply line 13 Large diameter chamber 14 High pressure supply line 15 Small diameter chamber 17 Restriction (first restriction)
18 Connection pipeline 19 Restriction (second restriction)
20 Housing 21 Sub-housing 22 Swash Plate 23 Shoe 24 Piston 25 Cylinder Block 26 Drive Shaft 30 Oblique Shaft Type Hydraulic Motor (Variable Capacity Hydraulic Motor)
31 Casing 32 Head Sector 33 Valve Plate 34 Cylinder Block 35 Center Rod 36 Piston 37 Disk Drive 38 Clearance 39 Oblique Shaft Control Mechanism (Capacity Control Device)

Claims (7)

Provided in a wheel-type construction machine equipped with a traveling body having tires,
A variable displacement hydraulic motor that drives the tire, and a displacement control device that controls the displacement of the variable displacement hydraulic motor,
The capacity control device includes a servo cylinder, a large-diameter chamber disposed at one end of the servo cylinder and connected to a control pressure supply line, to which a control pressure guided by the control pressure supply line is applied, and the servo cylinder In the traveling device of the wheel type construction machine having a small-diameter chamber that is arranged at the other end and connected to the high-pressure supply pipe and is given a high pressure guided by the high-pressure supply pipe,
A first throttle provided in the control pressure supply pipe, a connection pipe communicating the large diameter chamber and the small diameter chamber, and a second throttle provided in the connection pipe are provided. A traveling device for wheeled construction machines. In the traveling apparatus of the wheel type construction machine according to claim 1,
The variable displacement hydraulic motor includes a swash plate, a plurality of pistons each having a shoe slidably contacting the swash plate, a cylinder block in which these pistons are inserted and rotated as the piston reciprocates, and the swash plate A swash plate type hydraulic motor having a plate, a piston, a housing in which the cylinder block is accommodated, and a drive shaft that rotates integrally with the cylinder block and transmits a rotational force to the tire,
A traveling device for a wheel type construction machine, wherein the capacity control device comprises a swash plate control mechanism that is provided in the housing and controls the tilt of the swash plate. In the traveling device of the wheel type construction machine according to claim 2,
A traveling apparatus for a wheel-type construction machine, wherein the connecting pipe, the first throttle, and the second throttle are provided in the housing. In the traveling apparatus of the wheel type construction machine according to claim 1,
The variable displacement hydraulic motor includes a swingable valve plate, a cylinder block that is slidably contacted with the valve plate, a center rod that forms a central axis of the cylinder block, and a plurality of pieces that are fitted into the cylinder block. A piston, a part of the valve plate, the cylinder block, the center rod, and a casing in which the piston is accommodated, and each of the center rod and the piston are connected to each other and rotate as the cylinder block rotates. A slant shaft type hydraulic motor having a disk drive for transmitting rotational force to the tire,
A wheel characterized in that the capacity control device comprises a slant axis control mechanism that is connected to the casing and is provided in a head sector in which a part of the valve plate is accommodated, and controls swinging of the valve plate. Traveling equipment for construction machines. In the traveling device of the wheel type construction machine according to claim 4,
A traveling apparatus for a wheel type construction machine, wherein the connection pipe line, the first throttle, and the second throttle are provided in the head sector. In the traveling device of the wheel type construction machine according to claim 4,
Providing the first aperture in the head sector;
A traveling device for a wheel type construction machine, wherein the connecting pipe line and the second throttle are provided in the servo cylinder. In the traveling device of the wheel type construction machine according to claim 4,
Providing the first aperture in the head sector;
The connection pipe and the second throttle are formed of a gap formed between the outer peripheral surface of the servo cylinder and the inner peripheral wall of the head sector that houses the servo cylinder and faces the outer peripheral surface of the servo cylinder. A traveling device for a wheel-type construction machine.

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