JP2013104249A - Hydraulic pressure pulsation reducing device for work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic pressure pulsation reducing device for a work machine, capable of improving habitability in a cab by efficiently reducing the propagation of hydraulic pressure pulsation into the cab.SOLUTION: The hydraulic pressure pulsation reducing device includes an engine 31 mounted via a vibration proof rubber 35 on a base 23, a hydraulic pump 33 to be driven by the engine 31, a hydraulic pipe connected to the hydraulic pump 33, a hydraulic pressure pulsation reducing branch hose 39 whose base end side is connected to the discharge side of the hydraulic pump 33 and whose front end side is closed, and fixing means for fixing the branch hose 39 at its front end side. The used fixing means is a flange 42 formed integrally with a suction pipe 37, or a bracket 51 mounted on the engine 31 or the hydraulic pump 33.

Description

  The present invention relates to a hydraulic pulsation reducing device for a work machine, and more particularly to a means for reducing propagation of hydraulic pulsation into a cab that occurs when a hydraulic pump is operated.

  A work machine such as a hydraulic excavator is provided with a hydraulic pump driven by an engine and a hydraulic actuator driven by pressure oil supplied from the hydraulic pump. The hydraulic pump and the hydraulic actuator are connected to a hydraulic pipe. Are connected to each other.

  Since the hydraulic oil discharged from the hydraulic pump causes pulsation due to flow fluctuations, etc., among the hydraulic piping connecting the hydraulic pump and the hydraulic actuator, the hydraulic piping on the discharge side connected to the discharge port of the hydraulic pump (hereinafter referred to as the hydraulic pump) The pulsation is transmitted to the pressure oil flowing in the discharge pipe), and the discharge pipe vibrates with the pulsation of the pressure oil. This vibration increases and decreases according to changes in the discharge pressure of the hydraulic oil from the hydraulic pump and the rotation speed of the hydraulic pump. When the discharge pipe vibrates with the pulsation of the pressure oil, the vibration propagates to hydraulic equipment such as a hydraulic actuator to which the discharge pipe is connected, and a base that fixes the hydraulic pump and the discharge pipe. The working environment around the hydraulic pump deteriorates due to damage to the sound and the noise caused by vibration.

  As means for improving such problems, conventionally, a branch port communicating with a discharge port is provided in a hydraulic pump, and a branch hose made of a flexible hose with a closed end is connected to the branch port, and a discharge pipe is connected. A technique for attenuating the pulsation of pressure oil circulating inside is known.

  In this technology, the proximal end side of the branch hose with the closed end is connected to the branch port communicating with the discharge port of the hydraulic pump, so a part of the pressure oil discharged from the hydraulic pump to the discharge pipe when the hydraulic pump is operated. Is introduced into the branch hose, and the introduced pressure oil is reflected at the closed end and returns to the base end side, and merges with the pressure oil discharged to the discharge pipe. For this reason, the pulsation of the pressure oil returning to the base end side of the branch hose and the pulsation of the pressure oil discharged to the discharge pipe interfere and cancel each other. As a result, the pulsation of the pressure oil flowing through the discharge pipe is attenuated. Is done.

  As a hydraulic pulsation reducing device using this type of branch hose, the applicant of the present application first connects the base ends of two branch hoses to a branch block of a hydraulic pump, and these two branch hoses are reversed to each other. There has been proposed one in which the tip end side is fixed to a bracket welded to the base of the work machine in a state of being bent in the direction (see, for example, Patent Document 1). According to this hydraulic pulsation reducing device, the load acting on the bracket from the front end side of each branch hose is offset in the opposite direction, so that deformation and breakage of the bracket and its peripheral portion can be prevented. Moreover, since the force acting on the bracket can be suppressed, the bracket can be reduced in size and rigidity, the welding work of the bracket to the base can be facilitated, and the cost of the hydraulic pulsation reducing device can be reduced. Can do.

JP-A-8-296788

  However, since the hydraulic pulsation reducing device previously proposed by the present applicant is configured to fix the tip of the branch hose to the bracket welded to the base of the work machine, the hydraulic pulsation that could not be completely removed is It was transmitted to the cab through the base, and it was found that there was a problem that the comfortability in the cab could not be improved sufficiently.

  The present invention has been made in view of such problems of the prior art, and an object thereof is a work machine capable of efficiently reducing the propagation of hydraulic pulsation into the cab and improving the comfortability in the cab. An object of the present invention is to provide a hydraulic pulsation reducing device.

  In order to solve the above-mentioned problems, the present invention provides a prime mover mounted on a base via an anti-vibration rubber, a hydraulic pump attached to the prime mover and driven by the prime mover, and connected to the hydraulic pump. A hydraulic pipe, a branch hose for reducing hydraulic pulsation whose proximal end is connected to the discharge side of the hydraulic pump or in the middle of the hydraulic pipe, and whose distal end is closed, and fixing means for fixing the distal end of the branch hose In the hydraulic pulsation reducing device, the fixing means is provided in any one of the prime mover and the hydraulic pump or a device indirectly attached to the prime mover or the hydraulic pump via another member. .

  The engine is mounted on the base of the work machine through vibration-proof rubber, and the hydraulic pump is mounted on the engine. Therefore, when the distal end side of the branch hose is fixed to the fixing means attached to the prime mover or the hydraulic pump, the hydraulic pulsation of the branch hose is absorbed by the vibration isolating rubber, so that the propagation of the hydraulic pulsation to the base is prevented. The same applies to the case where the fixing means is provided not on the prime mover or the hydraulic pump itself but on a device indirectly attached to the prime mover or the hydraulic pump via another member. Therefore, propagation of hydraulic pulsation from the base to the cab is prevented, and the comfortability in the cab can be improved.

  According to the present invention, in the hydraulic pulsation reducing device for a work machine having the above-described configuration, a flange formed integrally with a suction pipe attached to the suction side of the hydraulic pump is used as the fixing means.

  A suction pipe is a member for connecting a suction side hydraulic pipe (hereinafter referred to as a suction pipe) to a suction port of a hydraulic pump, and is generally formed of an aluminum casting, and has a cylindrical rubber connected to one end. It is attached to the suction port of the hydraulic pump. Therefore, if the flange is formed integrally with the suction pipe and the tip end side of the branch hose is fixed to this flange, the hydraulic pulsation of the branch hose is absorbed by the anti-vibration rubber and is not propagated to the base, so that the comfortability in the cab is improved. Improved. In addition, a dedicated part such as a bracket for fixing the distal end side of the branch hose is not required, so that the cost of the work machine can be reduced by reducing the number of parts. Furthermore, since the fixing of the branch hose to the fixing means can be completed when the hydraulic pump is assembled to the engine, the fixing work of the branch hose can be facilitated.

  Further, the present invention provides a hydraulic pulsation reducing device for a work machine having the above-described configuration, wherein a bracket made of a plate material is used as the fixing means, and a base end portion of the bracket is fixed to the casing of the prime mover or the hydraulic pump. Features.

  When a bracket is used as a fixing means for fixing the distal end side of the branch hose, a general-purpose suction pipe having no flange can be used, so that an increase in component costs can be prevented. In addition, since the bracket can be assembled anywhere using bolts, nuts, etc., the degree of freedom in designing around the engine can be increased.

  In the present invention, the fixing means for fixing the distal end side of the branch hose is provided in any of the prime mover and the hydraulic pump or the equipment indirectly attached to the prime mover or the hydraulic pump via another member. Propagation of hydraulic pulsation to the base can be prevented, propagation of hydraulic pulsation from the base into the cab can be prevented, and comfort in the cab can be improved.

1 is a side view of a hydraulic excavator according to an embodiment. It is AA sectional drawing of FIG. It is a principal part perspective view in the machine room of the hydraulic shovel which concerns on embodiment. It is a perspective view of the suction pipe concerning an embodiment. It is a perspective view of the bracket which concerns on embodiment.

  Hereinafter, embodiments of a hydraulic pulsation reducing device according to the present invention will be described with reference to the drawings. The present invention can be applied to all work machines including a hydraulic pump driven by an engine such as a hydraulic excavator, a wheel loader, a dump truck, a bulldozer, and the like, and a hydraulic actuator driven by pressure oil discharged from the hydraulic pump. In the following description, a hydraulic pulsation reducing device provided in a hydraulic excavator will be described as an example.

  As shown in FIG. 1, the hydraulic excavator according to the embodiment is provided on a lower traveling body 1 driven to travel by a traveling hydraulic motor (not shown) and on the upper portion of the lower traveling body 1 so as to be capable of turning via a turning device 2a. The upper swing body 2 is driven to swing by a swing hydraulic motor (not shown), and the front working mechanism 3 provided in the upper swing body 2 is mainly configured. In addition, in the example of FIG. 1, although the crawler is used as the lower traveling body 1, it can replace with this and a tire can also be used.

  The upper swing body 2 is provided with a cab 5 that encloses the driver's seat 4 on the front side thereof, and a required operating device is provided in the cab 5. A counterweight 6 is provided at the rear end portion of the upper swing body 2, and a machine chamber 7 in which an engine, a hydraulic pump, and the like are accommodated is provided at a front portion of the counterweight 6.

  The front working mechanism 3 includes a boom 11 having one end rotatably connected to the upper swing body 2, a boom hydraulic cylinder 12 that drives the boom 11 up and down, and an arm having one end rotatably connected to the boom 11. 13, an arm hydraulic cylinder 14 for driving the arm 13 up and down, a bucket 15 whose one end is rotatably connected to the arm 13, and a bucket hydraulic cylinder 16 for driving the bucket 15 up and down. In addition, it can replace with the bucket 15 and can also attach other attachments, such as a crusher or a grappler.

  As shown in FIG. 2, the machine room 7 includes a base 23 composed of a turning frame 21 fixed to the turning device 2 a and a bottom plate 22 attached to the turning frame 21, and a cover that covers an upper portion of the base 23. It is comprised with the member 24. FIG. The machine room 7 houses an engine (prime mover) 31, a radiator 32 for cooling the engine 31, and a hydraulic pump 33 driven by the engine 31. The hydraulic pump 33 supplies pressure oil to the traveling hydraulic motor, the turning hydraulic motor, the boom hydraulic cylinder 12, the arm hydraulic cylinder 14, and the bucket hydraulic cylinder 16 through the discharge pipe 34 connected to the discharge port. Supply. In this example, a double hydraulic pump is used as the hydraulic pump 33.

  As shown in FIG. 3, the engine 31 is mounted on the center beam 21 a of the revolving frame 21 via a vibration isolating rubber 35. The hydraulic pump 33 is attached to the engine 31 via a bell flange 36. A suction pipe 38 is attached to the suction port of the hydraulic pump 33 via a cylindrical rubber 37, and a suction pipe (not shown) is connected to the other end side of the suction pipe 38.

  Reference numeral 39 in FIGS. 2 and 3 denotes a branch hose for reducing hydraulic pulsation. The branch hose 39 introduces a part of the pressure oil discharged from the hydraulic pump 33 to the discharge pipe 34, reflects the introduced pressure oil at the closed distal end side, and returns it to the proximal end side, thereby branching hose. The pulsation of the pressure oil returning to the base end side of 39 and the pulsation of the pressure oil discharged to the discharge pipe 13 are made to cancel each other, and the pulsation of the pressure oil flowing through the discharge pipe 13 is attenuated. The branch hose 39 is formed with a flexible hose, and a sealing plug 40 for screwing the portion to the closed end is screwed to the distal end side. The length of the branch hose 39 is set to a length that maximizes the canceling action of the hydraulic pulsation. As shown in FIG. 3, the branch hose 39 configured in this way is connected to the branch port of the hydraulic pump 33 on the base end side and is fixed to the suction pipe 37 via the sealing plug 40.

  The hydraulic pump 33 is driven by the engine 31 and sucks hydraulic oil from a hydraulic oil tank (both not shown) through the suction pipe and discharges it as pressure oil to the discharge pipe 34. The hydraulic oil discharged from the hydraulic pump 33 is suppressed in hydraulic pulsation by the branch hose 39 and supplied to each hydraulic motor and each hydraulic cylinder through the discharge pipe 34. Supply of the pressure oil to each hydraulic motor and each hydraulic cylinder is adjusted according to the operation amount and the operation direction of the operating device provided in the cab 5. As a result, the lower traveling body 1, the upper swing body 2 and the front work mechanism 3 are appropriately driven to perform necessary work such as excavation work.

  As shown in FIG. 4, the suction pipe 37 includes an elbow-shaped main body portion 41, two flanges 42 projecting symmetrically from the side surface portion of the main body portion 41, and a rear portion of the main body portion 41. And a rib 44 stretched between the flange 42 and the boss 43. These portions are integrally formed with an aluminum casting. A bolt through hole 45 is formed in the flange 41, and by screwing a screw portion of the bolt 46 penetrating through the bolt through hole 45 into a screw hole formed in the front portion of the sealing plug 40, The front end side of the branch hose 39 is fixed.

  In the hydraulic pulsation reducing device of this example, the flange 42 that is a fixing means of the branch hose 39 is formed integrally with the suction pipe 37, so that the hydraulic pulsation of the branch hose 39 is caused by the suction pipe 37, the cylindrical rubber 37, and the hydraulic pump 33. However, since the hydraulic pulsation propagated to the engine 31 is absorbed by the anti-vibration rubber 35, the hydraulic pulsation is not propagated to the turning frame 21 of the base 23. Therefore, propagation of hydraulic pulsation from the turning frame 21 into the cab 5 is prevented, and the comfortability in the cab 5 can be improved. Further, since the flange 42 is formed integrally with the suction pipe 37 made of an aluminum casting having excellent vibration absorption characteristics, the effect of absorbing hydraulic pulsation by the suction pipe 37 can be expected. Furthermore, since a dedicated part such as a bracket for fixing the distal end side of the branch hose 39 is not required, the cost of the work machine can be reduced by reducing the number of parts.

  In addition, since the fixing of the branch hose tip side can be completed when the hydraulic pump 33 is assembled to the engine 31, the fixing operation of the branch hose 39 can be facilitated, and the assembly cost of the work machine can be reduced. Can do. That is, when the distal end side of the branch hose 39 is fixed to the bracket attached to the turning frame 21 as in the prior art, the proximal end side of the branch hose 39 is hydraulically mounted when the hydraulic pump 33 is assembled to the engine 31. After the engine assembly connected to the branch port of the pump 33 and mounted with the hydraulic pump 33 is mounted on the turning frame 21 of the base 23, the work of fixing the distal end side of the branch hose 39 to the bracket must be performed. However, if the tip end side of the branch hose 39 is fixed to the suction pipe 37, the assembly of both ends of the branch hose 39 can be completed when the hydraulic pump 33 is assembled to the engine 31. Can be reduced.

  In the above embodiment, the flange 42 that is a fixing means for the branch hose 39 is formed integrally with the suction pipe 37. However, the gist of the present invention is not limited to this, and the engine 31, the hydraulic pump 33, Alternatively, the distal end side of the branch hose 39 can be fixed to another member connected to the engine 31 or the hydraulic pump 33 via a required connecting member. In this case, a plate-like bracket whose one end is fixed to the engine 31 or the like can be used as a fixing means for fixing the distal end side of the branch hose 39. FIG. 5 shows an example of a bracket applicable to this application. The bracket 51 of this example is formed in an L shape with a metal plate material, and two bolt through holes 52 and 53 are formed on each surface. The bolt through hole 52 is for penetrating a bolt for fixing the bracket 51 to the engine block or the like, and the bolt through hole 53 is for penetrating a bolt for fixing the distal end side of the branch hose 39.

  When the bracket 51 is used as a fixing means for the branch hose 39, a general-purpose suction pipe that does not have the flange 42 can be used, so that an increase in component costs can be prevented. In addition, since the bracket 51 can be assembled anywhere using bolts and nuts, the degree of freedom in designing around the engine can be increased. The effect of reducing hydraulic pulsation is the same as when the flange 42 formed on the suction pipe 37 is used as a fixing means for the branch hose 39.

  The present invention can be used for hydraulic work machines such as a hydraulic excavator, a wheel loader, and a dump truck.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper turning body 2a Turning apparatus 3 Front work mechanism 4 Driver's seat 5 Cab 6 Counterweight 7 Machine room 11 Boom 12 Boom hydraulic cylinder 13 Arm 14 Arm hydraulic cylinder 15 Bucket 16 Bucket hydraulic cylinder 21 Turning frame 21a Center beam 22 Bottom plate 23 Base 24 Cover member 31 Engine (motor)
32 Radiator 33 Hydraulic Pump 34 Discharge Piping 35 Anti-Vibration Rubber 36 Bell Flange 37 Cylindrical Rubber 38 Suction Pipe 39 Branch Hose 40 Sealing Plug 41 Main Body 42 Flange 43 Boss 44 Rib 45 Bolt Through Hole 51 Bracket 52, 53 Bolt Through Hole

Claims (3)

A prime mover mounted on a base via a vibration isolating rubber, a hydraulic pump attached to the prime mover and driven by the prime mover, a hydraulic pipe connected to the hydraulic pump, and a base end side of the hydraulic pump In a hydraulic pulsation reducing device comprising a branch hose for hydraulic pulsation reduction that is connected to the discharge side or in the middle of the hydraulic piping and whose tip side is closed, and a fixing means that fixes the tip side of the branch hose,
A hydraulic pulsation reduction device for a work machine, comprising: the fixing device provided in any one of the prime mover and the hydraulic pump or a device indirectly attached to the prime mover or the hydraulic pump via another member.   2. The hydraulic pulsation reducing device for a work machine according to claim 1, wherein a flange formed integrally with a suction pipe attached to the suction side of the hydraulic pump is used as the fixing means.   2. The hydraulic pulsation reduction device for a work machine according to claim 1, wherein a bracket made of a plate material is used as the fixing means, and a base end portion of the bracket is fixed to a casing of the prime mover or the hydraulic pump.