JP2012123725A - Control lever of work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize motion of a control lever following large vibration even when the large vibration occurs in a work machine.SOLUTION: Operation means 16 of a pilot valve device 15 provided in an operator cab has a control lever 31 consisting of a shaft part 32 and a grip part 33. A cam part 34 which presses and moves a pusher 29 is provided on the shaft part 32 of the control lever 31, and a dynamic vibration absorber 40 consisting of a mass and an elastic member is detachably provided at a position close to the grip part 33. The mass of the dynamic vibration absorber 40 is a ring-shaped member having a large diameter, and the elastic member is bonded to the inner peripheral surface of the dynamic vibration absorber. An attachment ring is fixedly mounted on the inner peripheral surface of the elastic member, and the attachment ring is fitted and fixed on the shaft part.

Description

  The present invention relates to an operation lever provided as an operation means for a work machine such as a hydraulic excavator.

  A working machine such as a hydraulic excavator includes a hydraulic pump, and a hydraulic actuator including a hydraulic cylinder and a hydraulic motor is driven by the hydraulic pump. The hydraulic pump operates multiple hydraulic actuators. Each hydraulic actuator is connected to the hydraulic pump via a control valve, and the return oil from each hydraulic actuator is returned to the hydraulic oil tank via the control valve. Is done.

  The hydraulic circuit provided in a hydraulic excavator or the like is as described above. In order to control the operation of the control valve, a traveling lever is usually provided at the front position of the driver's seat in the cab, and Operation levers are provided on both sides, and these are manually operated by an operator. One operation lever is provided on each of the left and right sides of the driver's seat, and the control valve is switched by tilting the operation lever in the left-right direction or the front-rear direction. When the control valve is controlled by a hydraulic pilot system, the operation lever is connected to the pilot valve, and the hydraulic pilot pressure from the pilot pump as the hydraulic source is configured by the operation of the operation lever. The directional switching valve is switched by being supplied to one of the pilot chambers provided at both ends of the switching valve.

  A specific configuration of the pilot valve is disclosed in Patent Document 1 and the like. The pilot valve is for connecting / blocking a pilot flow path provided between the pilot chamber of the control valve and the pilot pump. Therefore, the pilot valve has a spool for opening and closing the flow path, and a return spring acts on the spool. A pusher is provided to push the spool against the return spring. At normal times, the spool blocks the communication between the pilot pump and the pilot chamber by the action of the return spring. When the pusher is pushed against the return spring, the connection between the pilot pump and the pilot chamber is established. Thus, the pilot pressure acts in the pilot chamber, and the direction switching valve is switched. The operation lever is pivotally supported by the casing of the pilot valve, and a cam member is mounted in the vicinity of the pivot portion of the operation lever. Therefore, when the operating lever is tilted, the pusher is pushed against the return spring by the cam member, and the pilot flow path communicating with the pilot chamber of the direction switching valve to be controlled is connected to the pilot pump. The direction switching valve is switched.

JP 2007-2900 A

  By the way, the operator lever seated in the driver's seat is manually tilted back and forth and left and right, and a console box is provided on either the left or right side of the driver's seat. It is common to install. The operation lever protrudes greatly from the casing of the pilot valve, and may extend straight upward, obliquely upward, or bend in the middle. And the height, angle, etc. are set in consideration of the operability of the operation lever.

  Vibration is generated during operation of the work machine, and this vibration is also transmitted to the operation lever. The base end portion of the operation lever is pivotally supported by the pilot valve casing, and the distal end portion thereof is in a free state. Therefore, while the work machine is in operation, it vibrates continuously, the vibration is transmitted to the operation lever, and the operation lever swings around the pivot portion. Therefore, although the operation lever swings greatly due to resonance, the pusher is pushed in following the movement of the operation lever. As a result, the pilot pressure acts on the pilot chamber of the direction switching valve to switch the direction switching valve, which may impair the stability of the hydraulic actuator. In order to prevent such a situation from occurring, normally, even if the operating lever has a predetermined range of invalid stroke (play) and the operating lever is tilted to some extent, the spool does not switch for the invalid stroke. Is set.

  In working machines such as hydraulic excavators, pitching vibrations, rolling vibrations, translational vibrations, torsional vibrations, etc. occur in the swing frame when traveling on rough terrain or during work, and these vibrations are extremely large. It can be a thing. Naturally, this vibration is also transmitted to the operation lever, and depending on the magnitude of the acting vibration, the operation lever may swing greatly until it exceeds the invalid stroke. If the invalid stroke is extended to such a range, the operability of the operation lever is lowered, which is not desirable. Therefore, even if an invalid stroke is provided, there is a limit to increasing the invalid stroke.

  From the above, for example, when the excavator travels on rough terrain, the operator grips the travel lever and does not grip the front operation lever. It is inevitable that the spool is pushed by the cam member because the operating lever swings greatly due to the applied vibration. As a result, there is a risk of unintended operation of the working means and turning operation. In particular, from the viewpoint of operability of the operating lever, the operating lever is composed of a shaft provided with a grip at the tip, but the shaft is of a small diameter so that the operator can easily grip the grip on the tip. In order to achieve this, a large diameter grip portion is fitted to the shaft portion. For this reason, the tip is heavier than the base end side, and the possibility that the swing angle caused by the vibration of the operation lever exceeds the above-described invalid stroke is further increased.

  Further, if the spring force of the return spring acting on the spool is increased, the vibration resistance of the operation lever is improved, the stability thereof can be ensured, and the unintended operation can be prevented. However, since the switching operation of the spool is an operation of tilting the operation lever against the biasing force of the return spring, if the biasing force of the return spring is increased, the operability of the pilot valve switching operation is deteriorated. There is also a problem that it ends up.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress the movement of the operation lever following the vibration to a minimum even when a large vibration is generated in the work machine. Is to make it.

  In order to achieve the above-mentioned object, the present invention comprises a shaft portion and a grip portion provided at the tip of the shaft portion. An operating lever for operating and disconnecting a hydraulic pressure source and a pilot portion of the direction switching valve, wherein the shaft portion includes a mass and a spring member, and the spring member is The present invention is characterized in that a dynamic vibration absorber capable of vibrating the mass in a direction intersecting the axis of the shaft portion by being connected to the shaft portion is mounted.

  The operation lever is installed in the cab of a hydraulic excavator that performs work such as excavation of earth and sand on a work machine, such as rough terrain. Vibrations are transmitted to the operation lever during operation, and the vibration continues. A resonance phenomenon will occur. In addition, even if it is not a hydraulic shovel, it can also provide in self-propelled working machines, such as a hydraulic crane and a wheel loader.

  The dynamic vibration absorber is composed of a mass and a spring member, but the mass can be composed of a heavy metal member such as steel. The spring-like member can also be composed of an elastic member such as rubber, or a spring such as a leaf spring or a coil spring. The mass is provided with a through hole, and the spring member is mounted on the inner peripheral side of the mass through hole. The frequency that can be absorbed by the dynamic vibration absorber is determined by the weight of the mass and the spring constant of the spring member. The operation lever is composed of a shaft portion and a grip portion, and the dynamic vibration absorber is provided on the shaft portion so as not to obstruct the operation of the operation lever. The base end portion of the shaft portion is normally pivotally supported by the casing of the pilot valve unit, and the dynamic vibration absorber is provided at a position as far as possible from the pivotally supported portion, preferably close to the grip portion. .

  In order to attach the dynamic vibration absorber to the shaft portion, the spring member provided on the inner peripheral surface of the mass through hole is fixed to the inner surface of the through hole, and the spring member is fixed to the shaft portion. Retained. Although it is possible to fix the spring member directly to the shaft part, it is possible to attach the spring member to the outer peripheral surface of this mounting ring using the mounting ring, and detachably fix the mounting ring to the shaft part. It is desirable to adopt a configuration to do so. The connection of the spring-like member to the attachment ring and the mass may be detachable or may be fixed. In the case of fixing, it can be performed using an adhesive, but when the spring-like member is constituted by a leaf spring, it can be fixed by means such as welding and further on the outer peripheral surface of the mounting ring. A slit may be provided so that the end of a spring-like member made of a leaf spring is inserted.

  When traveling on rough terrain or when excavating earth and sand, the vibration is transmitted to the operating lever consisting of the shaft and grip, and swings around the pivot, further swinging due to resonance. To do. Since the dynamic vibration absorber is a main vibration system and suppresses swinging around the pivot of the operation lever, the mass is in the direction intersecting the axis of the shaft, preferably in the direction perpendicular to the axis of the shaft. An effective vibration absorbing function will be exhibited by vibrating it. It is not desirable in terms of the vibration absorbing function that the mass moves in the axial direction of the shaft portion or in a shallow angle direction with respect to the axial line. For this reason, it can be set as the structure which provides the stopper which restrict | limits the movement to the axial direction of the said shaft of the said mass in the both ends of an attachment ring.

  As a work machine, for example, in a driver's cab of a hydraulic excavator, a console is usually provided on both the left and right sides of the driver's seat, and an operation lever is attached to this console. Some of them are arranged so as to be inclined toward the operator side. In this case, the operating lever is directional in the direction of gravity, that is, because the load acts downward. In such a case, measures can be taken to decenter the mass. For example, when it is bent downward, the center of gravity of the mass is a diagonally upward position.

  In the pilot valve, the valve member operated by the operation lever is mounted so as to protrude from the upper surface of the casing. For this reason, in order to prevent foreign matter such as dust from entering between the valve member and its sliding portion, a flexible structure such as a bellows structure is provided between the upper surface of the pilot valve and the shaft portion of the operation lever. Generally, a boot made of a member is attached. In this case, it is desirable from the viewpoint of appearance and the like that the dynamic vibration absorber is provided inside the boot.

  Even if a large vibration occurs in the work machine, it is possible to minimize the movement of the operating lever following this vibration, and the swinging of the operating lever is restricted, causing unintended operation, that is, unintentional turning. There is less risk of movement or movement of the working means.

It is composition explanatory drawing of the hydraulic excavator as an example of the construction machine with which a pilot valve apparatus is equipped. It is a figure which shows the circuit structure of a pilot valve apparatus and the control valve controlled by this pilot valve apparatus. It is sectional drawing of the pilot valve apparatus which shows one Embodiment of this invention. It is a disassembled perspective view which shows the mounting part to the operation lever of the dynamic vibration damper of FIG. 3A and 3B show the dynamic vibration absorber of FIG. 3, in which FIG. 3A is a plan view and FIG. 3B is a longitudinal sectional view. The dynamic vibration absorber in a 2nd form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in a 3rd form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in a 4th form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in a 5th form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in a 6th form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in the 7th form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. The dynamic vibration absorber in the 8th form is shown, Comprising: (a) is a top view, (b) is a longitudinal cross-sectional view. It is a longitudinal cross-sectional view which shows the dynamic vibration damper in a 9th form. It is a longitudinal cross-sectional view which shows the dynamic vibration damper in a 10th form.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 shows an overall configuration of a hydraulic excavator as an example of a construction machine. In the figure, 1 is a lower traveling body, 2 is an upper revolving body, and 3 is a revolving device provided between the lower traveling body 1 and the upper revolving body 2. The upper swing body 2 is provided with a cab 4 for an operator to sit on and operate the machine, and a working means 5 is mounted. The working means 5 includes a boom 6, an arm 7, and a bucket 8 as a front attachment.

  The traveling by the lower traveling body 1 and the turning of the upper turning body 2 by the turning device 3 are each driven by a hydraulic motor. The boom 6, the arm 7 and the bucket 8 are driven by a boom cylinder 6a, an arm cylinder 7a and a bucket cylinder 8a which are hydraulic cylinders, respectively. Each of these hydraulic motors and hydraulic cylinders is provided with a pair of input / output ports as hydraulic actuators. And it drives by supplying pressure oil to one port and making the other port the return side.

  For this reason, the input / output port of the hydraulic actuator is connected to the hydraulic pump 11 and the hydraulic oil tank 12 via the control valve 10 so as to be switchable as shown in FIG. The control valve 10 is switched by a hydraulic pilot system, and hydraulic pilot pipes 13L and 13R are connected to both hydraulic pilot portions 10L and 10R of the control valve 10, respectively. Then, switching control of the control valve 10 is performed by connecting one of the hydraulic pilot pipes 13L and 13R to the pilot pump 14 and connecting the other to the hydraulic oil tank 12.

  In order to perform the switching control of the control valve 10 described above, a pilot valve device 15 is provided in the cab 4. As shown in FIG. 3, the pilot valve device 15 includes an operation means 16 and a valve unit 17. The valve casing 18 of the valve unit 17 has a hydraulic pilot pipe 13 </ b> L described above as an output pipe. , 13R are connected. Further, a hydraulic pipe 19 from the pilot pump 14 and a return pipe 20 to the hydraulic oil tank 12 are connected to the valve unit 17, and when the operating means 16 is operated, one of the pilot pipes 13L and 13R is connected to the valve unit. As a result of being connected to the hydraulic pipe 19 connected to 17 and the other connected to the return pipe 20, a differential pressure is generated between the hydraulic pilot portions 10L and 10R of the control valve 10, and the control valve 10 is switched. .

  The pilot valve device 15 is for a front operating lever, and is provided on a console cover 21 provided on the side of the driver's seat in the cab. The valve unit 17 constituting the pilot valve device 15 is disposed below the console cover 21, and the operation means 16 protrudes from the console cover 21. The valve casing 18 of the valve unit 17 is provided with valve chambers 22, 22 on the left and right, and a spool 23 is slidably mounted in both valve chambers 22. The valve chamber 22 is provided with a hydraulic port 24 connected to the hydraulic pipe 19 on the high pressure side, and a low pressure port 25 connected to the return pipe 20. The spool 23 connects the output port 26 with the low pressure port 25 and hydraulic pressure. This is for switching to and from the port 24. Therefore, the spool 23 is in a state where both the output ports 26 are connected to the low pressure port 25 by the biasing force of the return spring 27, and either one of the spools 23 resists the biasing force of the return spring 27. Then, the output port 26 is connected to the hydraulic port 24 and the hydraulic pilot signal is supplied to either the hydraulic pilot portion 10L or 10R in the control valve 10.

  The return spring 27 acts on a spring receiver 28, and a tip of a connecting rod 23 a connected to the spool 23 is attached to the spring receiver 28. A pusher 29 is in contact with the spring receiver 28. A valve end plate 30 is connected to the upper end of the valve casing 18 constituting the valve unit 17, and the pusher 29 protrudes upward from the surface of the valve end plate 30. The valve end plate 30 is attached to the console cover 21, and the pilot valve device 15 is fixed to the console cover 21. The switching of the flow path in the valve unit 17 described above is performed by pushing one of the pushers 29. In addition, the valve unit 17 including the valve chamber 22, the spool 23, and the pusher 29 is provided in two sets on the front and rear and on the left and right, for a total of four sets.

  The operating means 16 for operating the valve unit 17 is for pushing the pusher 29 and slidingly displacing the spool 23 in the valve chamber 22. For this purpose, the operation means 16 has an operation lever 31 for front operation, and the operation lever 31 is provided with a grip portion 33 on the shaft portion 32 for an operator to hold and operate. A cam portion 34 is provided at the base end side position of the shaft portion 32 of the operation lever 31, and the cam surface 34 a of the cam portion 34 is in contact with the distal end portion of the pusher 29. In order to push and operate any one of the four pushers 29 provided by the cam portion 34, the operation lever 31 is supported by the valve end plate 30 so as to be tiltable left and right and back and forth. A pivot portion 35 is provided so as to protrude, and an operation means 16 including an operation lever 31 and a cam portion 34 is connected to the pivot portion 35 via a universal joint 36.

  In a state where the pilot valve device 15 is mounted on the console cover 21, the universal joint 36 projecting upward and the abutting portion between the cam portion 34 and the pusher 29 are covered, and from the valve end plate 30 of the pusher 29. A seal member 37 is attached to the protruded portion, and an airtight structure is used in order to enhance the sealability of this portion. Therefore, a boot 38 is mounted between the boundary portion between the grip portion 33 and the shaft portion 32 of the operation lever 31 and the valve end plate 30, and the inside of the boot 38 is sealed. The boot 38 has a bellows structure composed of a spring member such as rubber.

  As is clear from FIG. 4, the grip portion 33 connected to the shaft portion 32 is composed of a grip portion 33 a and a core material 33 b made of a member such as plastic or rubber, and the tip of the boot 38 is at this tip. It is inserted between the grip portion 33a and the core material 33b. The core material 33b is provided with a screw hole, and the tip end portion of the shaft portion 32 is screwed into the screw hole. A dynamic vibration absorber 40 is attached to the shaft portion 32 in the vicinity of the tip thereof, that is, in the vicinity of the grip portion 33.

  As is clear from FIG. 5, the dynamic vibration absorber 40 includes a mass 41 and an elastic member 42, and the mass 41 is formed of a ring-shaped member having a predetermined weight, for example, a metal material. For example, it is made of rubber or the like and is also formed in an annular shape. Then, by setting the weight of the mass 41 and the spring constant of the elastic member 42 so as to be approximately equal to the natural frequency of the operation lever 31 constituting the main vibration system, the vibration of the dynamic vibration absorber 40 is applied to the operation lever 31. The control lever 31 can be prevented or suppressed from swinging due to the balance with the transmitted vehicle vibration.

  Fig.5 (a) is a top view of the dynamic vibration damper 40, FIG.5 (b) is a longitudinal cross-sectional view including the center position. The mass 41 in the dynamic vibration absorber 40 is located on the outer peripheral side, and the elastic member 42 is located on the inner peripheral side. The mass 41 and the elastic member 42 are fixed by means such as adhesion. The inner peripheral surface of the elastic member 42 is fixed to the outer peripheral surface of the mounting ring 43 by means such as adhesion, and the mounting ring 43 is detachably fixed to the shaft portion 32. The dynamic vibration absorber 40 is disposed inside the boot 38, and its mounting ring 43 is attached to the shaft portion 32. Upper and lower stoppers 45 and 46 are provided at upper and lower positions of the mounting ring 43, and the mounting ring 43 is sandwiched between the upper and lower stoppers 45 and 46. A nut 47 is screwed into a position below the stoppers 45 and 46 in the shaft portion 32, and the mounting ring 43 and both stoppers 45 and 46 are fixedly held by the grip portion 33 by the nut 47. ing.

  The stopper 45 on the upper side is provided integrally with the core member 33b of the grip portion 33, or is configured as a separate member. Then, the nut 47 is screwed into the shaft portion 32, and the stopper 46 and the dynamic vibration absorber 40 are sequentially screwed into the shaft portion 32. In this state, the tip of the shaft portion 32 is screwed into the core member 33b of the grip portion 33. By doing so, the shaft part 32 and the grip part 33 are connected in a state in which the dynamic vibration absorber 40 is incorporated. Here, the shaft portion 32 and the attachment ring 43 are screwed together, whereby there is no possibility that the attachment portion of the dynamic vibration absorber 40 to the shaft portion 32 is rattled. The dynamic vibration absorber 40 is disposed between the stoppers 45 and 46, although the mass 41 is interposed through a slight gap, and between the mass 41 and the elastic member 42 and between the elastic member 42 and the mounting ring 43. Even if the adhesive between the two deteriorates, there is no possibility of dropping off from the shaft portion 32.

  The dynamic vibration absorber 40 is for suppressing the vibration of the operation lever 31 by resonating with the vibration of the operation lever 31 when the operation lever 31 vibrates. In order to effectively suppress the vibration of the operation lever 31, it is necessary to appropriately set the weight of the mass 41 and the spring constant of the elastic member 42 as a spring member in accordance with the relationship between the total length and the total weight of the operation lever 31. is there. Since the movement of the operation lever 31 is oscillating around the pivot portion 35, the vibration direction of the mass 41 in the dynamic vibration absorber 40 is a direction substantially perpendicular to the axis of the shaft portion 32 or a slight angle therefrom. By limiting to the holding direction, a higher vibration absorbing function is exhibited.

  The stoppers 45 and 46 are for limiting the movement of the mass 41 to a direction substantially orthogonal to the axis of the shaft portion 32, and there is a slight gap between the stoppers 45 and 46 and the mass 41. Thus, the movable range is limited. However, flange portions 43a and 43a having a predetermined thickness are formed at the upper and lower ends of the mounting ring 43. Therefore, the elastic member 42 is kept in a non-contact state with respect to the stoppers 45 and 46, and the mass 41 The movement is prevented from being restricted by the stoppers 45 and 46.

  While the hydraulic excavator is in operation, the entire upper swing body 2 vibrates, and this vibration is transmitted to the operation lever 31, and the tip side swings around the pivot portion 35, and swings greatly due to the resonance action. It will be. A dynamic vibration absorber 40 is mounted on the shaft portion 32 of the operation lever 31. The mass 41 constituting the dynamic vibration absorber 40 follows the swing of the operation lever 31 in a direction intersecting the axis of the shaft portion 32. As a result of vibration, the swing of the operation lever 31 constituting the main vibration system is suppressed. Therefore, a situation in which one of the hydraulic actuators is operated despite unintentional occurrence does not occur.

  As described above, the dynamic vibration absorber 40 is provided in order to exhibit the vibration absorption function of the operation lever 31. The dynamic vibration absorber 40 is a small and compact structure that is mounted around the shaft portion 32 of the operation lever 31. Therefore, the operation lever 31 as a whole is not significantly enlarged. In addition, since the dynamic vibration absorber 40 is provided inside the boot 38 and is not exposed to the outside, there is no difference in appearance from the case where the vibration absorbing mechanism of the operation lever 31 is not provided.

  By the way, although the shaft part 32 can also be made into a straight rod-like member as a whole, in consideration of the operability of the operation lever 31 performed while sitting on the driver's seat, as shown in FIG. Is tilted. For this reason, the shaft portion 32 is bent at an intermediate position thereof, and the portion from the base end side to the middle becomes the vertical portion 32a, and the vertical portion 32a becomes the inclined portion 32b. A bent portion is formed at the base end, and the base end side extends straight from the bent portion B and is pivotally attached to the pivot portion 35. Accordingly, the grip portion 33 connected to the front end side of the shaft portion 32 is bent so that the front end side rises toward the front side of the operator seated in the driver's seat, thereby reducing the burden on the operation of the grip portion 33. ing.

  Thus, in the operation lever 31 having the shaft portion 32 composed of the vertical portion 32a and the inclined portion 32b, the position of the center of gravity is the position of the vertical line of the pivot portion 35 that becomes the swing center of the operation lever 31. It is a position that is biased from. Therefore, when the excavator is in operation, the operation lever 31 has a large swing width in the direction in which the grip portion 33 is inclined, that is, in the gravity direction, and a small swing width in the opposite direction, that is, in the antigravity direction. For this purpose, the mass constituting the dynamic vibration absorber and the spring member are not concentric with the mounting ring, but are eccentric.

  The dynamic vibration absorber 40A shown in FIGS. 6 (a) and 6 (b) uses a mass 41A having an elliptical shape to form a through hole at a position offset in the longitudinal direction from the center thereof, and has the above-mentioned inside. The elastic member 42A similar to that shown in the first embodiment is fixed by an adhesive means. The elastic member 42A is fixedly provided on the outer peripheral surface of the mounting ring 43A. Further, the dynamic vibration absorber 40B shown in FIGS. 7A and 7B is rectangular in a planar state and uses a mass 41B having a predetermined thickness, and is attached to the mass 41B at a position offset in the longitudinal direction. A through hole for mounting the elastic member 42B connected to the ring 43B is formed.

  The dynamic vibration absorbers 40A and 40B are fixed to the inclined portion 32b of the shaft portion 32 with the protruding sides of the masses 41A and 41B directed in the antigravity direction, that is, upward. As a result, when the operation lever 31 is swung, the inertial force acts in the anti-gravity direction when the masses 41A and 41B vibrate with respect to the movement in the direction of falling downward. A high vibration absorbing function can be exerted on the operation lever 31.

  When the hydraulic excavator is operated, the upper swing body 2 provided with the cab 4 vibrates in various directions. Specifically, pitching vibration, rolling vibration, translational vibration, torsional vibration, and the like. Four pushers 29 with which the cam surface 34a of the cam portion 34 abuts are provided. Therefore, the operation lever 31 swings in the left and right and front and rear directions, and the swinging direction and the inertial force acting when swinging differ depending on the direction. For example, the pitching vibration that acts during excavation of earth and sand has a large vibration amplitude, the rolling vibration has a relatively small amplitude, and both have different vibration frequencies. The pitching vibration mainly acts in the front-rear direction of the upper swing body 2, and the rolling vibration mainly acts in the left-right direction of the upper swing body 2. Therefore, as shown in FIGS. 8A and 8B, as the dynamic vibration absorber 40C, the elastic member 42C provided between the mass 41C and the mounting ring 43C is used regardless of the size and shape of the mass 41C. A circular ring formed by connecting arc-shaped pieces of approximately 90 degrees can be used. And the spring constant of each piece which comprises the elastic member 42C is changed. In the drawing, the arc-shaped piece 42hC is a hard piece having a large spring constant, and the arc-shaped piece 42sC is a soft piece having a small spring constant. For example, for pitching vibrations that vibrate up and down at a relatively high frequency, the upper and lower pieces are composed of hard pieces 42hC, and for rolling vibrations that vibrate in a horizontal direction at a relatively low frequency, the left and right pieces are The soft piece is 42sC. Accordingly, the dynamic vibration absorber 40 can have an optimal spring constant according to the nature of the vibration that acts.

  In each of the above-described embodiments, the elastic member such as rubber is used as the springy member constituting the dynamic vibration absorber. However, as shown in FIGS. 9A and 9B, the mass 51 The dynamic vibration absorber 50 having a configuration in which the leaf spring 52 is interposed between the mounting ring 53 and the mounting ring 53 can be used. The leaf spring 52 is formed by bending so as to have a mountain fold portion and a valley fold portion, and has an endless shape in which both ends are connected so as to form an annular shape. The tip of the bent portion of the leaf spring 52 is assembled to the inner peripheral surface of the mass, and the tip of the valley bent portion is pressed to the outer peripheral surface of the mounting ring 53.

  Here, the dynamic vibration absorber 50 is fixed in a state where the mounting ring 53 is inserted through the shaft portion 32 of the operation lever 31, and the dynamic vibration absorber 50 absorbs the swinging motion around the pivot portion 35 of the operation lever 31. Done. In order to absorb the swinging motion of the operation lever 31, it is desirable that the mass 51 basically vibrates in a direction orthogonal to the axis of the shaft portion 32 and does not vibrate in other directions. The mass 51 is orthogonal to the axis of the shaft portion 32 when an external force is applied by fixing the mountain-folded portion and the valley-folded portion of the leaf spring 52 to the inner peripheral surface of the mass 51 and the outer peripheral surface of the mounting ring 53. The vibration of the shaft portion 32 as the main vibration system can be suppressed by the resonance action. As described above, since the spring member is composed of the leaf spring 52, the mass 51 can move only in this vibration absorption direction, and does not move in other directions, for example, in the axial direction of the shaft portion 32 or the like. Therefore, it exhibits a high vibration absorption function.

  In this dynamic vibration absorber 50, the leaf spring 52 bends in the direction of the plate surface and does not deform in other directions. Therefore, when the motion absorber 50 is mounted on the shaft portion 32, it is not necessary to regulate the movement of the mass 51 in the axial direction of the shaft portion 32, and it is necessary to provide a stopper for regulating the movement of the mass 51. Absent. However, the dynamic vibration absorber 50 is provided with stoppers 55 and 56 at both ends of the mounting ring 53 in order to prevent the mass 51 and the leaf spring 52 from falling off. Since the mass 51 does not move in the axial direction of the shaft portion 32 due to the action of the leaf spring 52, the stoppers 55 and 56 are at least partially brought into contact with both end faces of the mass 51.

  Further, as shown in FIGS. 10A and 10B, flange portions 51Af and 53Af are formed at both ends on the inner peripheral surface of the mass 51A constituting the dynamic vibration absorber 50A and the outer peripheral surface of the mounting ring 53A, respectively. And it can also comprise so that the mountain fold part and valley fold part of 52 A of leaf | plate springs may be clamped, respectively. With this configuration, the dynamic vibration absorber 50A can be assembled so that the leaf spring 52A is sandwiched between the mass 51A and the mounting ring 53A. In this state, the mass 51 </ b> A and the leaf spring 52 </ b> A are stably held, and there is no possibility of dropping off from the attachment ring 53 </ b> A, so there is no need to provide a stopper.

  The dynamic vibration absorber 50B shown in FIGS. 11 (a) and 11 (b) uses a plurality of leaf springs 52B formed in a V-shape, and the leg pieces that the leaf springs 52B expand are as follows. Inserted into mounting grooves 54B formed at predetermined angular intervals on the outer peripheral surface of the mounting ring 53B. The apex portion of each leaf spring 52B is in pressure contact with the inner peripheral surface of the mass 51B, whereby the mass 51B is fixedly held by the attachment ring 53B via the leaf spring 52B. In this case, since the mass 51B is not fixed, the mass 51B is sandwiched between the stoppers 55B and 56B in order to prevent dropping. Moreover, the mounting groove 54B is open at the end of the mounting ring 53B on the side where the stopper 56B is joined, and the leaf spring 52B is held by the flange portion 56B so that the leaf spring 52B does not fall off by incorporating the stopper 56B. .

  Furthermore, the dynamic vibration absorber 50C shown in FIGS. 12A and 12B uses a plurality of leaf springs 52C, one end side of which is the inner peripheral surface of the mass 51C, and the other end side is the attachment ring 53C. It is set as the structure welded to the outer peripheral surface.

  Even when a leaf spring is used as the spring member, as shown in FIGS. 7A and 7B, the spring constant is made different depending on the vibration direction as in the case of the dynamic vibration absorber 40C. It can also be configured. For example, as shown in FIG. 13, a configuration in which a leaf spring 52D bent so as to have a mountain fold portion and a valley fold portion is interposed between a mass 51D constituting the dynamic vibration absorber 50D and a mounting ring 53D. The pitch interval of the leaf spring 52D can be varied such that the upper and lower parts of the leaf spring 52D are denser and the left and right parts are rougher. Further, as shown in FIG. 14, in the dynamic vibration absorber 50E in which a plurality of leaf springs 52E are fixed between the mass 51E and the mounting ring 53E, the number of leaf springs 52D and the fixing positions are determined. Can also be configured to vary in the circumferential direction.

DESCRIPTION OF SYMBOLS 1 Lower traveling body, 2 Upper turning body, 4 Operator's cab, 15 Pilot valve apparatus, 16 Operation means, 17 Valve unit, 21 Console cover, 23 Spool, 27 Return spring, 29 Pusher, 31 Operation lever, 32 Shaft part, 33 Grip part, 34 cam part, 40, 40A, 40B, 40C, 50, 50A, 50B, 50C, 50D, 50E Dynamic vibration absorber, 41, 41A, 41B, 41C, 51, 51A, 51B, 51C, 51D, 51E Mass 42, 42A, 42B, 42C Elastic member, 52, 52A, 52B, 52C, 52D, 52E Leaf spring, 43, 43A, 43B, 43C, 53, 53A, 53B, 53C, 53D, 53E, 45, 46, 44 , 55, 56, 55B, 56B Stopper

Claims (5)

It consists of a shaft part and a grip part provided at the tip of this shaft part, and is provided in the pilot valve unit, and by operating the tilting operation, the valve member of the pilot valve unit is operated to An operating lever that communicates with and disconnects from the pilot section.
The shaft portion includes a mass and a spring-like member, and the spring-like member is connected to the shaft portion so as to vibrate the mass in a direction intersecting the axis of the shaft portion. An operation lever for a working machine, characterized in that the operation lever is mounted. A mounting ring is mounted on the shaft portion, the mass is a ring-shaped member inserted through the shaft portion, and the spring member is fixedly provided on an inner peripheral surface of the ring-shaped member. 2. The structure according to claim 1, wherein an elastic member is fitted to the mounting ring, and stoppers are provided at both ends of the mounting ring to limit movement of the mass in the axial direction of the shaft. The operating lever of the described working machine. The shaft portion is formed with a bent portion in the middle, and the mounting ring is provided closer to the grip portion than the bent portion of the shaft portion, and is mounted so that the position of the center of gravity of the mass is eccentric. The operating lever of the work machine according to claim 2, wherein the operating lever is configured as described above. The operation lever of the work machine according to claim 3, wherein the gravity center position of the mass in the shaft portion is mounted so as to be eccentric in the antigravity direction. The side of the pilot valve from which the valve member protrudes is covered with a boot made of a flexible member, and the dynamic vibration absorber is arranged inside the boot. The operation lever of the working machine according to claim 4.

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