JPH0988119A - Hydraulic oil pulsation reducing device for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unreasonable force from being exerted when a side branch is vibrated due to vibration of a construction machine during operation. SOLUTION: In a hydraulic oil pulsation reducing device in which the pulsation of hydraulic oil generated in a hydraulic pump 2 mounted on a building machine is transmitted into a side branch through a discharge side passage, and is reflected by a reflecting surface in the branch so as to reduce the pulsation, a delivery port of the hydraulic pump 2 is connected thereto with delivery port blocks 4a, 4b. Side branch pipe lines 7a, 7b having opposite ends opened so as to constitute the side branch, are connected at their one end to side branch connecting ports 6a, 6b so as to be communicated with a discharge side passage from the hydraulic pump within the delivery port blocks 4a, 4b in order to be fixed to the hydraulic pump, and are fixed with their other end abutted on wall surfaces 8a, 8b of the hydraulic pump. The wall surfaces 8a, 8b are used as the reflecting surfaces in the side branch. Thus, the side branch is constituted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a side branch having one end branched and connected to a discharge side flow path of a hydraulic pump mounted on a construction machine, and a reflecting surface provided at the other end. The present invention relates to a pressure oil pulsation reducing device for a construction machine, in which the pulsation of the pressure oil is reduced by the side branch.

[0002]

2. Description of the Related Art In construction machines such as hydraulic excavators and hydraulic cranes, a hydraulic pump such as a plunger pump is mounted as a source of pressure oil for driving actuators such as a traveling motor and a boom. Pump
Pulsation of pressure oil is generated during the repeated process of discharge and suction of the hydraulic pump. The pulsation of the pressure oil propagates in the pressure oil pipeline,
Since it is transmitted to various hydraulic devices connected to this pipeline and causes noise, and in some cases it may cause resonance and damage pipes and hydraulic devices, it is necessary to reduce it as much as possible. Conventionally, a side-branch type pressure oil pulsation reducing device has been generally known as one of means for reducing such pressure oil pulsation.

This side-branch type pressure oil pulsation reducing device branches and attaches a bottomed branch side branch to a pressure oil passage through which pulsating pressure oil passes, thereby pulsating the pressure oil of a specific frequency component. The pulsation of the pressure oil passing through the inside of the pressure oil pipe is propagated from the base end opening of the side branch into the side branch, and then with the reflecting surface forming the tip closing part of the side branch. The light is reflected and returned to the pressure oil pipe. Since the side-branch pressure oil pulsation reducer employs such a configuration, the pulsating wave of the pressure oil of the specific frequency component to be reduced is predetermined, and the length of the side-branch passage is set according to the frequency. With proper adjustment, the pulsating wave of pressure oil that travels back and forth through the side branch and returns to the conduit of pressure oil collides with the pulsating wave of pressure oil that passes through the conduit of pressure oil and the peaks and troughs of the wave. Since they can be interfered with each other in a matching relationship, the pulsation of the specific frequency component of the pulsation of the pressure oil passing through the pressure oil conduit can be reduced intensively.

[0004] The actual Kaihei 6 listed here to show the prior art
No. 18465 discloses such a side-branch type pressure oil pulsation reducing device. This pressure oil pulsation reduction device is for reducing pump noise caused by pressure oil pulsation of the hydraulic pump mounted on the construction machine, and is provided in the discharge side flow path of the hydraulic pump formed in the delivery port block. It has a side branch with one end branched and connected and a reflection surface provided on the other end, and the pulsation of pressure oil generated by the hydraulic pump is propagated into the side branch through the discharge side flow path and reflected by the reflection surface. By doing so, the amount is reduced. In this publication, when the side branch of the pressure oil pulsation reducing device is attached to a construction machine such as a hydraulic excavator, conventionally, the base end opening part of the side branch is connected to the delivery port side of the hydraulic pump and attached, and the tip closing part is attached. Since it was fixed to a bracket or the like above the rubber mount for engine mounting, it could be damaged by the vibration of the construction machine and cause oil leakage, and we have proposed a side branch mounting structure to solve these problems. The side branch mounting structure is that "the side branch is formed to have rigidity and is set to a predetermined length, and the base end opening of the side branch is connected and fixed to the delivery port side of the hydraulic pump, and The closing part is not fixed, or the tip closing parts of a plurality of side branches are connected via an unfixed block material. "

[0005]

However, the side branch attached to the construction machine such as a hydraulic excavator has a length of about 1 m, which is long. Therefore, for example, the technique disclosed in the above-mentioned publication is used. Even if it is made to have rigidity as described above, it is inevitable that the tip closed portion side, which is the free end, is vibrated by the vibration during the operation of the construction machine. Depending on the type of work, the construction machine may generate a large vibration during the work, and when the side branch is vibrated by such a large vibration and this is repeated, the side branch fixed to the delivery port side of the hydraulic pump. Fatigue occurs on the base end opening side of the branch, and in the worst case, it may be damaged and cause oil leakage.
For this reason, it is preferable that the side branch is fixed so that the tip closing portion does not move toward the main body of the construction machine as long as it is possible to prevent an excessive force from being applied when the side branch is vibrated.

The present invention was created based on this recognition of the prior art. The purpose of the present invention is to make the side branch work when the construction machine is working even if the tip of the side branch is fixed to the construction machine body side. It is an object of the present invention to provide a pressure oil pulsation reducing device for a construction machine, which is not subjected to an excessive force or damaged when being vibrated by the vibration.

[0007]

The object of the present invention is to provide a "side branch having one end branched and connected to the discharge side flow path of a hydraulic pump mounted on a construction machine and a reflecting surface provided at the other end. In the pressure oil pulsation reducing device of the construction machine, the pulsation of the pressure oil generated in the hydraulic pump is reduced by propagating it into the side branch through the discharge side flow path of the hydraulic pump and reflecting it on the reflecting surface. , One end of the side branch pipe, which is open at both ends to form the side branch, is connected to the discharge side flow passage of the hydraulic pump and fixed to the hydraulic pump, and the other end is brought into contact with the wall surface of the hydraulic pump. By fixing and also using this wall surface as the reflecting surface of the side branch, the side branch is formed and attached. " It is achieved by the construction machine of the hydraulic fluid pulsation reducing device as it is.

[0008]

Since the pressure oil pulsation reducing apparatus for a construction machine according to the present invention has such a structure, when pressure oil pulsation occurs in the hydraulic pump, the pressure oil pulsation is generated in the discharge side flow path of the hydraulic pump. And the pulsation of the pressure oil propagated in the side branch pipeline is reflected by the wall surface of the hydraulic pump and returns to the discharge side flow path of the hydraulic pump again. The pulsation is reduced by interfering with the pulsation of the pressure oil passing through the discharge side flow path. Since both ends of the side branch composed of the side branch pipe and the wall surface of the hydraulic pump are fixed to the hydraulic pump at the same time, they are in phase with the hydraulic pump when they are vibrated by the vibration during the work of the construction machine. It vibrates and is not subject to excessive force.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a top view of a pressure oil pulsation reducing device for a construction machine according to an embodiment of the present invention. A pressure oil pulsation reducing device for a construction machine according to an embodiment of the present invention is a hydraulic pump 2 mounted on a construction machine, similar to the conventional technique proposed in the above-mentioned publication.
For reducing the pulsation of the pressure oil, the side having one end branched and connected to the discharge side flow path of the hydraulic pump 2 formed in the delivery port blocks 4a and 4b and the other end provided with a reflection surface. The pulsation of the pressure oil generated by the hydraulic pump 2 has a branch, and is propagated into the side branch through the discharge side flow path and reflected by the reflection surface to reduce the pulsation. Is no different from conventional technology.

The technical contents of this embodiment will be described in detail with reference to FIG. 1. In FIG. 1, 1 is an engine, 2 is a hydraulic pump which is driven by the engine 1 and serves as a source of pressure oil for driving an actuator. 4a and 4b are delivery port blocks connected to the hydraulic pump 2, and 7a and 7b.
b is a side branch pipe for forming a side branch connected to the delivery port blocks 4a and 4b, and 9a and 9b are also delivery port blocks 4a and 4b.
It is a delivery hose connected to 4b. Hydraulic pump 2
Consists of 2 independent plunger pumps, so 2
There are two delivery ports, and two delivery port blocks are provided, including blocks 4a and 4b. As described above, the hydraulic pump 2 including the two independent plunger pumps is shown in this embodiment only in that the basic configuration is adapted to the technology disclosed in the above-mentioned publication. The number of pumps is not a critical factor in practicing the present invention. Further, the hydraulic pump does not necessarily have to be the plunger pump as in the present embodiment, but may be another type of hydraulic pump such as a vane pump or a gear pump.

Each delivery port block 4a, 4b has a delivery port connecting port 3a, 3b for connecting to the delivery port of the hydraulic pump 2 and a delivery hose connecting port for connecting to each inlet of the delivery hoses 9a, 9b. 5a, 5b and side branch pipe line 7
Side branch connecting ports 6a and 6b for connecting to the respective inlets of a and 7b are formed. The delivery port blocks 4a and 4b include delivery port connection ports 3a and 3b and delivery hose connection port 5.
A discharge side flow path of the hydraulic pump communicating with a and 5b, and a branch flow path which is branched and connected to the discharge side flow path of the hydraulic pump and communicates with the side branch connecting ports 6a and 6b are formed. . The delivery port blocks 4a and 4b are
In this embodiment, the hydraulic pump 2 is attached to the outer surface of the casing, but it may be attached to the casing.

Both ends of the side branch conduits 7a and 7b are open, and one end thereof is connected to the side branch connecting port 6
a and 6b are connected to the delivery port blocks 4a and 4b through branch flow passages in the blocks 4a and 4b.
Connect to the discharge side flow path of the hydraulic pump inside. The side branch conduits 7a, 7b are connected at their one ends to the flow paths in the delivery port blocks 4a, 4b in this way,
The hydraulic pump 2 is fixed via the blocks 4a and 4b. Also, at the other end, a flange portion 7c,
7d is provided, and the flange portions 7c and 7d are brought into contact with and fixed to the wall surfaces 8a and 8b of the hydraulic pump 2,
8b forms the reflecting surface of the side branch, and the hydraulic pump 2
The wall surfaces 8a and 8b are also used as the reflecting surfaces of the side branches. In the present embodiment, the side branch is different from the conventional one in this way, and the side branch line 7
a, 7b and the wall surfaces 8a, 8b of the hydraulic pump 2. An appropriate fixing means can be used to fix the other ends of the side branch conduits 7a, 7b to the wall surfaces 8a, 8b of the hydraulic pump 2. Side branch pipeline 7
Although a and 7b are made of metal pipes in this embodiment, they may be made of flexible and pressure-resistant hoses. The delivery hoses 9a and 9b form a part of the pipeline of the hydraulic drive circuit of the construction machine, and the main pipeline of the circuit is connected.

Since the pressure oil pulsation reducing device of the construction machine of this embodiment has such a structure, when pressure oil pulsation occurs in the hydraulic pump 2, this pressure oil pulsation is generated by the respective port for connecting the delivery ports. The side branch connection ports 6a, 6 propagate from the delivery port 3a, 3b to the discharge side flow passage of the hydraulic pump in each delivery port block 4a, 4b, and through the branch flow passage in each delivery port block 4a, 4b.
It also propagates from b to the inside of each side branch pipeline 7a, 7b. The pulsation of the pressure oil propagating in the side branch pipelines 7a, 7b is reflected by the wall surfaces 8a, 8b of the hydraulic pump 2, and again delivered through the branch passages in the delivery port blocks 4a, 4b. Port blocks 4a, 4
It returns to the discharge side flow path of the hydraulic pump in b and interferes with the pulsation of the pressure oil passing through the discharge side flow path to reduce the pulsation.
Further, since both ends of the side branch constituted by the side branch pipes 7a, 7b and the wall surfaces 8a, 8 and b of the hydraulic pump 2 are fixed to the hydraulic pump 2 by the vibration during the work of the construction machine. When vibrated, it does not vibrate in the same phase as the hydraulic pump 2 and receives an unreasonable force. That is, the side branch vibrates along with the hydraulic pump 2 when the hydraulic pump 2 vibrates during the operation of the construction machine, but both ends are fixed to the hydraulic pump 2, and the side branches have a relative end portion. Since the positional relationship does not substantially change even when vibrating, the side branch is not twisted or pulled, and an unreasonable force is not applied.

Therefore, according to this embodiment, even if the tip of the side branch is fixed to the construction machine body side, an excessive force is applied when the side branch is vibrated by the vibration during the work of the construction machine. A pressure oil pulsation reducing device for a construction machine that is not damaged can be obtained, and therefore, the side branch does not leak oil. Further, since the wall surface 8a, 8b of the hydraulic pump 2 is used in place of the reflective surface forming component to be provided at the tip of the side branch conduits 7a, 7b, the processing and assembling steps of such component can be omitted. It also contributes to the reduction of production costs.

[0015]

As is apparent from the above description, the present invention is directed to a pressure oil pulsation reducing device for a side-branch construction machine, in which a side-branch line is open at both ends for forming a side-branch. One end is connected to the discharge side flow path of the hydraulic pump and fixed to the hydraulic pump, and the other end is brought into contact with and fixed to the wall surface of the hydraulic pump, and this wall surface is also used as the reflecting surface of the side branch. Since the end of the side branch is fixed to the main body of the construction machine, the side branch receives an excessive force or is damaged when it is vibrated by the vibration during the work of the construction machine. It is possible to obtain a pressure oil pulsation reduction device for a construction machine that does not suffer from rust. Further, since the wall surface of the hydraulic pump is also used as the reflecting surface of the side branch, it contributes to the reduction of the manufacturing cost of the pressure oil pulsation reducing device.

[Brief description of drawings]

FIG. 1 is a top view of a pressure oil pulsation reducing device for a construction machine according to an embodiment of the present invention.

[Explanation of symbols]

 1 Engine 2 Hydraulic Pump 3a, 3b Delivery Port Connection Port 4a, 4b Delivery Port Block 5a, 5b Delivery Hose Connection Port 6a, 6b Side Branch Connection Port 7a, 7b Side Branch Pipeline 7c, 7d Side Branch Pipe Flange Parts 8a, 8b Walls of hydraulic pump 9a, 9b Delivery hose

Claims (1)

[Claims] 1. A side branch having one end branched and connected to a discharge side flow path of a hydraulic pump mounted on a construction machine and a reflecting surface provided at the other end, for pulsating pressure oil generated in the hydraulic pump. In a pressure oil pulsation reducing device for a construction machine, which is propagated into a side branch through a discharge side flow path of a hydraulic pump and reflected by a reflection surface of the side branch,
Both ends for forming a side branch are open, and one end of the side branch pipe is connected to the discharge side flow passage of the hydraulic pump and fixed to the hydraulic pump, and the other end is abutted and fixed to the wall surface of the hydraulic pump. A pressure oil pulsation reducing device for a construction machine, characterized in that the wall is also used as a reflecting surface of the side branch to form and attach the side branch.