JPH08218426A - Hydraulic pulsation reducer - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the pulsation of the pressure oil flowing through the hydraulic pipe connected to the hydraulic pump, and to suppress the vibration of the hydraulic pipe due to the pulsation of the pressure oil and the noise caused by this vibration. A tip end side of a branch hose 17 is fixed to a mounting bracket 18 via an elastic member 24, and the elastic member 24
A hard rubber 25 and a soft rubber 26 having different elastic constants from each other.
It is configured by combining and. As a result, the pulsation of the pressure oil can be attenuated by the pulsating interference action of the branch hose 17, and
The hard rubber 25 constituting the elastic member 24 prevents the pulsation in the frequency band that cannot be attenuated by the pulsation interference action of the branch hose 17,
Of the soft rubbers 26, the soft rubbers 26 can mainly dampen, so the pulsation reducing effect of the branch hose 17 and the pulsation reducing effect of the hard rubber 25 and the soft rubber 26
The pulsation of the pressure oil flowing through the hydraulic pipe can be reduced over a wide frequency band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pulsation reducing device for reducing the occurrence of vibration or noise in hydraulic piping connected to a hydraulic pump due to pulsation of pressure oil discharged from the hydraulic pump.

[0002]

2. Description of the Related Art Generally, a hydraulic device represented by a construction machine comprises a hydraulic pump and a hydraulic actuator operated by pressure oil supplied from the hydraulic pump. The hydraulic pump and the hydraulic actuator are connected via a hydraulic pipe. Are connected to each other to form a hydraulic circuit.

By the way, the pressure oil discharged from the hydraulic pump, which is the hydraulic pressure source, causes pulsation, and therefore, of the hydraulic pipes connecting the hydraulic pump and the hydraulic actuator, particularly on the discharge side connected to the discharge port of the hydraulic pump. Pulsations are transmitted to the pressure oil flowing in the hydraulic pipe (hereinafter referred to as the discharge side pipe). Therefore, the discharge side pipe vibrates with the pulsation of the pressure oil, and this vibration increases or decreases according to the discharge pressure of the pressure oil from the hydraulic pump and the change in the rotational speed of the hydraulic pump. And
When the discharge side pipe vibrates with the pulsation of pressure oil, hydraulic equipment such as a hydraulic actuator to which the discharge side pipe is connected,
There are problems that vibration propagates to a structure such as a frame that supports the discharge side pipe, damages these hydraulic devices and structures, and causes noise associated with the vibration to deteriorate the work environment around the hydraulic pump.

In order to improve such a problem, for example, as disclosed in Japanese Utility Model Publication No. 6-18465, a branch hose is connected to the discharge port of the hydraulic pump separately from the discharge side pipe. Therefore, it is known that the pulsation of the pressure oil flowing in the discharge side pipe can be attenuated.

The tip end side of this branch hose is a closed end, and when the hydraulic pump operates, a part of the pressure oil discharged from the hydraulic pump to the discharge side pipe is introduced into the branch hose.
Then, the pressure oil introduced into the branch hose is reflected at the closed end of the branch hose and returns to the base end side, and merges with the pressure oil discharged to the discharge side pipe, whereby mutual pulsations are interfered with each other to cancel each other. As a result, the pulsation of the pressure oil flowing through the discharge side pipe can be damped.

[0006]

By connecting the branch hose to the discharge port of the hydraulic pump separately from the discharge side pipe as described above, the pulsation of the pressure oil flowing through the discharge side pipe can be reduced. However, the pulsation that can be damped by the interference effect of the branch hose is normally limited to within a certain frequency band, so that the pulsation outside this frequency band remains undamped. For this reason, minute pulsations are constantly generated on the tip side of the branch hose, and the pulsations generated on the tip side of the branch hose propagate to structures such as hydraulic equipment and frames to induce noise. There is a problem that the working environment around the pump is significantly deteriorated.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to reduce the pulsation of the pressure oil discharged from the hydraulic pump and reduce the vibration and noise of the hydraulic piping due to the pulsation of the pressure oil. An object is to provide a hydraulic pulsation reduction device.

[0008]

In order to solve the above-mentioned problems, the present invention provides a hydraulic pump, a hydraulic pipe connected to the hydraulic pump, and a basal end for reducing pulsation generated in the hydraulic pipe. Side is connected to the discharge side of the hydraulic pump or in the middle of the hydraulic pipe and the tip side is closed, a part of the pressure oil is introduced, a fixing means for fixing the branch hose, and the fixing means. On the other hand, the present invention is applied to a hydraulic pulsation reducing device including an elastic member provided between the fixing means and the branch hose so as to elastically support the branch hose.

The feature of the configuration adopted by the invention of claim 1 is that the elastic member is located on the first elastic body that abuts on the outer peripheral side of the branch hose, and is located outside the first elastic body. It is composed of a second elastic body, and the elastic constants of the first and second elastic bodies are different from each other.

In this case, it is preferable that the elastic constant of the first elastic body is larger than that of the second elastic body.

According to a third aspect of the present invention, the fixing means includes a pressing plate for sandwiching the branch hose with the mounting bracket through the first and second elastic bodies, and the pressing plate. And a fastening member that fastens the first and second elastic bodies between the mounting bracket, and the first and second fastening members by the fastening member.
It is preferable that the second elastic body is composed of a spacer provided between the mounting bracket and the pressing plate to adjust the fastening force with respect to the second elastic body.

Further, according to the invention of claim 4, a branch block is provided on the discharge side of the hydraulic pump, and the hydraulic pipe is connected to the branch block and the proximal end side of the branch hose is connected. be able to.

[0013]

According to the structure of claim 1, a part of the pressure oil discharged to the discharge side of the hydraulic pump or the pressure oil flowing through the hydraulic piping is introduced into the branch hose, and the pressure oil introduced into the branch hose is introduced. Are reflected at the closed end of the branch hose and return to the base end side, and merge with the pressure oil discharged to the discharge side of the hydraulic pump or the pressure oil flowing in the hydraulic pipe, so that the pulsations interfere with each other and cancel each other out. Thus, the pulsation generated in the hydraulic pipe is damped. At this time, the minute pulsation generated on the tip side of the branch hose due to the pulsation that cannot be completely damped by the pulsation interference action of the branch hose is damped by the elastic member composed of the first and second elastic bodies. At this time, since the elastic constants of the first elastic body and the second elastic body are different from each other, the pulsation that cannot be completely damped by the branch hose is damped by the elastic body having the lower elastic constant. Can be made.

In this case, according to the second aspect of the invention, the branch hose is firmly supported by the first elastic body which is in contact with the outer peripheral side of the branch hose, and the pulsation of the branch hose is of the first elastic body. It is damped by the second elastic body located outside and having a small elastic constant.

According to the third aspect of the invention, the branch hose is fastened by the fastening member between the mounting bracket and the pressing plate via the first and second elastic bodies. At this time,
By adjusting the fastening force of the fastening member with respect to the first and second elastic bodies by the spacer, it is possible to prevent the deformation due to the excessive fastening force acting on the first and second elastic bodies.

Further, according to the structure of claim 4, when the pressure oil flows to the hydraulic pipe through the branch block provided on the discharge side of the hydraulic pump, the base end side is connected to the branch block. Part of the pressure oil is introduced into the branch hose,
The pressure oil introduced into the branch hose is reflected at the closed end of the branch hose and returns to the base end side, whereby the pulsation of the pressure oil generated in the hydraulic pipe near the discharge port of the hydraulic pump is attenuated.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First, FIGS. 1 to 5 show a first embodiment of the present invention.
The above embodiment is shown in a state in which it is applied to a hydraulic pump arranged in a machine room of a hydraulic excavator.

In FIG. 1, 1 is a lower traveling body, 2 is an upper revolving body provided on the lower traveling body 1 so as to be rotatable, and the upper revolving body 2 is provided with a revolving device (not shown). A swivel frame 3 provided on the lower traveling structure 1 so as to be swivelable, a driver's cab 4 provided on the front side of the swivel frame 3, and an operator's cab
A machine room 5 located on the rear side of the machine room 5 and provided on the revolving frame 3 and a counterweight 6 installed on the rear side of the machine room 5 are roughly configured. Reference numeral 7 denotes a working device located laterally of the operator's cab 4 and provided on the front side of the revolving frame 3 so that the working frame 7 can be lifted and lowered.
The hydraulic cylinders 8 are provided with 8, ...

Reference numeral 11 denotes a hydraulic pump arranged in the machine room 5 of the hydraulic excavator, and the hydraulic pump 11 is the machine room 5
It is fixed inside a housing of an engine (not shown) or the like provided on the revolving frame 3 and discharges pressure oil when the engine is in operation.

Reference numeral 12 denotes a suction side pipe whose base end side is connected to the suction port side of the hydraulic pump 11, and the suction side pipe 12
The tip end side of is extended into the hydraulic oil tank (not shown) through the subframe 3A extending upward from the swivel frame 3.

Reference numeral 13 denotes a branch block connected to the discharge port side of the hydraulic pump 11, and the branch block 13
Has a main port to which a discharge side pipe 14 described later is connected and a branch port to which a branch hose 17 is connected.

Reference numeral 14 denotes a discharge side pipe connected to the discharge port of the hydraulic pump 11 via the branch block 13.
The discharge side pipe 14 has a branching block 13 at the base end side.
The front end side is connected to the manifold of the multi-valve 15, respectively. Here, the multiple valve 15 is an assembly of control valves for controlling the supply of pressure oil to various hydraulic actuators mounted on the hydraulic excavator, and the discharge side pipe 1
The pressure oil from the hydraulic pump 11 supplied to the manifold of the multiple valve 15 via 4 is passed through a hydraulic pipe (not shown) connected to the discharge port of each control valve forming the multiple valve 15. And is selectively supplied to a predetermined hydraulic actuator. Reference numeral 16 is a return oil pipe whose base end side is connected to the manifold of the multiple valve 15 and whose front end side extends into the tank. The return oil pipe 16 returns the hydraulic oil returned from the hydraulic actuator to the multiple valve 15 to the tank. It is for.

Reference numeral 17 denotes a branch hose whose base end side is connected to the branch port of the branch block 13 and is connected to the discharge port side of the hydraulic pump 11 via the branch block 13, and the tip end side of the branch hose 17 is shown. Has a closed end 17A. Then, the branch hose 17 introduces a part of the pressure oil discharged from the hydraulic pump 11 into the discharge side pipe 14, reflects the introduced pressure oil at the closed end 17A and returns it to the base end side, and the discharge side pipe 14 By merging with the pressure oil discharged to
The pulsations of the pressure oil flowing through the discharge side pipe 14 are attenuated by interfering and canceling each other's pulsations.

Reference numeral 18 is a mounting bracket for fixing the tip end side of the branch hose 17 to the revolving frame 3, and the mounting bracket 18 has a bent shape as shown in FIG. 3, and the lower end side thereof has a plurality of bolts 19, 19. , And are fixed to the sub-frame 3A of the revolving frame 3. Further, on the upper end side of the mounting bracket 18, two bolt insertion holes 18A, 18A are formed as shown in FIG.

Reference numeral 20 denotes a fixing means for fixing the tip end side of the branch hose 17 to the mounting bracket 18, and the fixing means 20 is roughly composed of a pressing plate 21, a fastening member 22, a cylindrical spacer 23 and the like which will be described later. There is.

Reference numeral 21 denotes a pressing plate that holds the tip end side of the branch hose 17 between it and the mounting bracket 18 via an elastic member 24, which will be described later. The pressing plate 21 is formed of a steel plate material or the like into a rectangular plate shape. , Each bolt insertion hole 1 of the mounting bracket 18
Bolt insertion holes 21A, 21A are formed at two locations corresponding to 8A.

Reference numeral 22 is a fastening member for fastening the elastic member 24 between the mounting bracket 18 and the pressing plate 21, and the fastening member 22 is each bolt insertion hole 21A of the pressing plate 21 and each bolt insertion hole 18A of the mounting bracket 18. It is composed of bolts 22A and 22A which are inserted into and, and nuts 22B and 22B which tighten the bolts 22A from the mounting bracket 18 side.

Reference numerals 23 and 23 denote a pair of cylindrical spacers which are arranged between the mounting bracket 18 and the pressing plate 21 and each bolt 22A is inserted in the hollow portion.
3 acts on the elastic member 24 when the elastic member 24 is fastened by the fastening member 22 between the mounting bracket 18 and the pressing plate 21 by setting the distance between the mounting bracket 18 and the pressing plate 21. The tightening force is adjusted. This prevents the elastic member 24 from being deformed due to an excessive fastening force acting on the elastic member 24 and impairing the pulsation damping action of the elastic member 24.

Reference numeral 24 designates an elastic member located on the outer peripheral side of the branch hose 17 and provided between the mounting bracket 18 and the pressing plate 21, and the elastic member 24 is provided at its central portion with the cap portion 17B of the branch hose 17. Semi-circular engagement recess 25 that fits in
A pair of hard rubbers 25, 25 as first elastic bodies in which A is formed and spacer insertion holes 25B, 25B are formed at two positions sandwiching the engagement recess 25A, and the outside of each hard rubber 25. And a pair of soft rubbers 26, 26 as a second elastic body having two spacer insertion holes 26A, 26A in the longitudinal direction.
5 is formed in a block shape, and each soft rubber 26 is formed in a plate shape.

Here, the hard rubber 25 and the soft rubber 26 are formed with elastic constants different from each other, and the hard rubber 25 as the first elastic body is the base 17 of the branch hose 17.
It is made of a hard rubber material (having a large elastic constant) that is excellent in wear resistance in order to prevent wear of the contact portion with B. On the other hand, the soft rubber 26 as the second elastic body does not directly contact the branch hose 17 but also contacts the hard rubbers 25 with a relatively large area, so that the damping force against pulsation is exclusively increased. It is made of a soft (small elastic constant) rubber material.

When the tip end side of the branch hose 17 is fixed to the mounting bracket 18 via the elastic member 24, the base 17B of the branch hose 17 is sandwiched by the engaging recess 25A of the hard rubber 25 and the hard rubber 25
With the soft rubber 26 in contact with the outside of the hard rubber 2
After inserting the cylindrical spacer 23 into the spacer insertion hole 25B of 5 and the spacer insertion hole 26A of the soft rubber 26, the branch hose 17, the elastic member 24, and the cylindrical spacer 23 are sandwiched between the mounting bracket 18 and the pressing plate 21, and the bolt 22A. Are sequentially inserted into the bolt insertion hole 21A of the pressing plate 21, the hollow portion of the cylindrical spacer 23, and the bolt insertion hole 18A of the mounting bracket 18, and the nut 22B is tightened from the mounting bracket 18 side. As a result, the pressing plate 21 is bolted to the mounting bracket 18 via the cylindrical spacer 23, and the tip end side of the branch hose 17 is elastically supported between the mounting bracket 18 and the pressing plate 21 via the elastic member 24. To be done.

The hydraulic pulsation reducing device according to this embodiment has the above-mentioned structure, and its operation will be described below.

First, the engine operates to operate the hydraulic pump 11
By driving the hydraulic pump 1, the hydraulic oil in the tank is sucked into the hydraulic pump 11 via the suction side pipe 12, and the hydraulic pump 1
Pressure oil accompanied by pulsation is discharged from the discharge port No. 1. Then, most of this pressure oil is introduced into the discharge side pipe 14 via the branching block 13 and is supplied to a predetermined hydraulic actuator via the multiple valve 15 or the like to operate the hydraulic actuator.

On the other hand, a part of the pressure oil discharged from the discharge port of the hydraulic pump 11 is introduced into the branch hose 17 through the branch block 13, and the closed end 17 of the branch hose 17 is introduced.
It reflects at A and returns to the branch block 13, and the discharge side pipe 1
It joins with the pressure oil introduced in 4. As a result, the pulsation of the pressure oil returning from the closed end 17A of the branch hose 17 and the pulsation of the pressure oil discharged to the discharge side pipe 14 interfere with each other to cancel each other, and as a result, the pressure oil flowing through the discharge side pipe 14 is canceled. Pulsations are dampened.

At this time, on the tip side of the branch hose 17,
Although the pulsation interference effect of the branch hose 17 as described above causes a minute pulsation that cannot be completely attenuated, the tip end side of the branch hose 17 is made of a hard rubber 25 and a soft rubber 26 having an elastic constant smaller than that of the hard rubber 25. Since it is sandwiched between the mounting bracket 18 and the pressing plate 21 via the elastic member 24, the minute pulsation generated on the tip side of the branch hose 17 can be effectively damped mainly by the soft rubber 26. Therefore, it is possible to suppress the vibration and noise accompanying the minute pulsation generated on the tip end side of the branch hose 17 from propagating to the swing frame 3 via the mounting bracket 18, the subframe 3A, etc. It is possible to maintain a comfortable working environment in the cab 4 of the hydraulic excavator.

When the tip end side of the branch hose 17 is supported between the mounting bracket 18 and the pressing plate 21 via the elastic member 24, the hard rubber 2 which constitutes the elastic member 24.
5, hard rubber 25 having a large elastic constant of soft rubber 26
Is brought into contact with the mouthpiece portion 17B of the branch hose 17, and the soft rubber 26 is disposed outside the hard rubber 25, so that the tip end side of the branch hose 17 is attached to the mounting bracket 18 and the pressing plate 2.
It can be elastically and firmly supported between the two. Moreover, since the hard rubber 25 has excellent wear resistance, it is possible to reduce the wear of the contact portion with the branch hose 17, and the hard rubber 2
5. The pulsation damping action of the elastic member 24 made of the soft rubber 26 can be appropriately maintained for a long period of time.

As described above, according to this embodiment, most of the pulsation of the pressure oil generated during the operation of the hydraulic pump 11 can be damped by the pulsating interference action of the branch hose 17, and the pulsating interference action of the branch hose 17 can be reduced. The pulsation in the frequency band that cannot be completely attenuated by the soft rubber 2 having a small elastic constant among the hard rubber 25 and the soft rubber 26 constituting the elastic member 24.
It can be attenuated by 6. Therefore, the pulsation reducing action of the branch hose 17 and the pulsation reducing action of the elastic member 24 made of the hard rubber 25 and each soft rubber 26 can reduce the pulsation of the pressure oil during the operation of the hydraulic pump 11 over a wide frequency band. The working environment in the cab 4 of the hydraulic excavator can always be kept in a comfortable state. Moreover, since the wear of the elastic member 24 can be reduced by bringing the hard rubber 25 having a large elastic constant into contact with the outer periphery of the branch hose 17, the pulsation damping action of the elastic member 24 can be appropriately maintained for a long period of time. it can.

Further, by changing the elastic constants of the hard rubber 25 and the soft rubber 26 in various ways, it is possible to prepare a combination of the elastic members 24 which can obtain an optimum pulsation damping action according to the frequency band of pulsation. Therefore, the pulsation frequency changes according to the discharge pressure of the pressure oil from the hydraulic pump 11 and the rotational speed of the hydraulic pump 11, and the pulsation in a specific frequency band that cannot be attenuated by the pulsating interference action of the branch hose 17 increases. Even in the case of doing, by using the elastic member 24 that can obtain the optimum pulsation damping action with respect to the pulsation of this specific frequency band,
The pulsation can be effectively damped.

Further, at low temperature, the rubber material is hardened and the damping action against pulsation is also reduced. However, by combining the hard rubber 25 and the soft rubber 26 having improved pulsation damping characteristics at low temperature, the hydraulic pressure is maintained even at low temperature. Pump 1
The pulsation of the pressure oil during the operation of No. 1 can be attenuated, and the vibration and noise accompanying this pulsation can be suppressed.

Next, FIGS. 6 and 7 show a second embodiment of the present invention.
Is shown. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

In the figure, 31 indicates a mounting bracket fixed to the suction side pipe 12, and the mounting bracket 31 is a pair of leg portions 31 facing each other while being separated in the axial direction of the suction side pipe 12.
A, 31A and a supporting portion 31 connecting between the leg portions 31A
Each of the legs 31 </ b> A is welded to the outer circumference of the discharge side pipe 14 and is firmly fixed to the suction side pipe 12. Then, the support portion 3 of the mounting bracket 31
The tip end side of the branch hose 17 is attached to 1B via an elastic member 24.

The present embodiment has the above-mentioned structure, and other structures and operations are similar to those of the first embodiment.

According to this embodiment, however, the branch hose 1
Since the tip end side of 7 is fixed to the suction side pipe 12 via the mounting bracket 31 and the elastic member 24, the branch hose 17 can be arranged along the suction side pipe 12, The space required to accommodate 17 can be reduced.

In each of the above embodiments, the hard rubber 25 is used as the first elastic body forming the elastic member 24, and
The case where the soft rubber 26 is used as the elastic body has been described as an example, but the present invention is not limited to this. For example, as the first elastic body, two or more kinds of rubbers having different elastic constants are combined. The second elastic body may be a combination of two or more kinds of rubbers having different elastic constants.

In each of the above embodiments, the hydraulic pump 11
The branch block 13 is provided on the discharge port side of the above, and the case where the base end side of the branch hose 17 is connected to this branch block 13 has been described as an example, but the present invention is not limited to this, and for example, The base end side of the branch hose 17 may be connected to the middle of the side pipe 14, the position of the multiple valve 15, or the like.

Further, in each of the above-mentioned embodiments, the case where the present invention is applied to the hydraulic pump arranged in the machine chamber 5 of the hydraulic excavator has been described as an example, but the present invention is not limited to this, and for example, the hydraulic pressure is used. It can be widely applied to other construction machines such as cranes, bulldozers, and wheel loaders, as well as hydraulic pumps provided in various industrial machines.

[0048]

As described above in detail, according to the invention of claim 1, when the branch hose is fixed by the fixing means,
An elastic member provided between the fixing means and the branch hose is composed of a first elastic body that abuts on the outer peripheral side of the branch hose and a second elastic body located outside the first elastic body. However, since the elastic constants of the first and second elastic bodies are made different from each other, the pulsation generated in the hydraulic pipe can be damped by the pulsating interference action of the branch hose, and the pulsating interference action of the branch hose is damped. The pulsation in the frequency band that cannot be completely suppressed can be attenuated by the elastic body having the lower elastic constant, of the first and second elastic bodies. Therefore,
Due to the pulsation damping action of the branch hose and the pulsation damping action of the elastic member composed of the first and second elastic bodies, the pulsation of the pressure oil during the operation of the hydraulic pump can be reduced over a wide frequency band, and the pulsation is accompanied. By suppressing the vibration and noise, the working environment around the hydraulic pump can be always kept comfortable.

According to the invention of claim 2, the wear of the contact portion of the elastic member with the branch hose is reduced by increasing the elastic constant of the first elastic body contacting the outer peripheral side of the branch hose. it can. Therefore, the pulsation damping action of the elastic member including the first and second elastic bodies can be appropriately maintained for a long period of time. Further, by changing the elastic constants of the first and second elastic bodies in various ways, it is possible to create a combination of elastic members that can obtain an optimum pulsation damping action according to the pulsation frequency band. Therefore, when the pulsation frequency changes according to the discharge pressure of the hydraulic oil from the hydraulic pump and the rotational speed of the hydraulic pump, and the pulsation in a specific frequency band that cannot be attenuated by the pulsating interference action of the branch hose increases. Also, the pulsation can be effectively damped by using the elastic member that can obtain the optimum pulsation damping action with respect to the pulsation in the specific frequency band. Further, by improving the pulsation damping characteristics of the first and second elastic bodies forming the elastic member at low temperatures, it is possible to effectively dampen the pulsations of pressure oil generated in the hydraulic pipe even at low temperatures. .

According to the third aspect of the present invention, the branch hose is fastened by the fastening member between the mounting bracket and the pressing plate via the first and second elastic bodies. Since the fastening force with respect to the first and second elastic bodies can be adjusted by the spacer, the first and second elastic bodies are deformed by the excessive fastening force acting on the first and second elastic bodies. It is possible to prevent the pulsation damping action from being impaired.

Further, according to the invention of claim 4, by connecting the branch hose to the branch block provided on the discharge side of the hydraulic pump, the hydraulic pressure near the discharge port of the hydraulic pump can be maintained when the hydraulic pump is in operation. Since the pulsation of the pressure oil flowing in the pipe can be attenuated, the pulsation generated in the hydraulic pipe connected to the discharge side of the hydraulic pump can be attenuated over substantially the entire area.

[Brief description of drawings]

FIG. 1 is an external view showing a hydraulic excavator to which an embodiment of the present invention is applied.

FIG. 2 is an external view showing the hydraulic pulsation reducing device according to the first embodiment of the present invention in a state where the hydraulic pulsation reducing device is arranged in a machine chamber of a hydraulic excavator.

FIG. 3 is an enlarged view of a main part with a partially broken view showing a fixing means, an elastic member and the like shown in FIG.

FIG. 4 is an exploded perspective view of fixing means, elastic members and the like shown in FIG.

FIG. 5 is an enlarged cross-sectional view seen from the direction VV of the arrow in FIG.

FIG. 6 is an external view of a hydraulic pulsation reducing device according to a second embodiment of the present invention at the same position as in FIG.

FIG. 7 is an enlarged cross-sectional view taken along the line VII-VII in FIG.

[Explanation of symbols]

 11 Hydraulic Pump 12 Suction Side Pipe (Hydraulic Pipe) 13 Branch Block 14 Discharge Side Pipe (Hydraulic Pipe) 17 Branch Hose 18, 31 Mounting Bracket 20 Fixing Means 21 Pressing Plate 22 Fastening Member (Fixing Means) 22A Bolt (Fastening Member) 22B Nut (fastening member) 23 Cylindrical spacer (fixing means) 24 Elastic member 25 Hard rubber (first elastic body) 26 Soft rubber (second elastic body)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Uchike 650 Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Engineering Co., Ltd.

Claims (4)

[Claims] 1. A hydraulic pump, a hydraulic pipe connected to the hydraulic pump, and a basal end side connected to a discharge side of the hydraulic pump or in the middle of the hydraulic pipe in order to reduce pulsation generated in the hydraulic pipe. And a branch hose whose front end is closed and a part of the pressure oil is introduced, fixing means for fixing the branch hose, and branching with the fixing means for elastically supporting the branch hose with respect to the fixing means. In the hydraulic pulsation reducing device including an elastic member provided between the hose and the hose, the elastic member is located outside the first elastic body and a first elastic body that abuts an outer peripheral side of the branch hose. And a second elastic body, wherein the first and second elastic bodies have different elastic constants from each other. 2. The elastic constant of the first elastic body is set to the second constant.
The hydraulic pulsation reducing device according to claim 1, wherein the elastic constant is larger than the elastic constant of the elastic body. 3. The pressing means holds the branch hose via the first and second elastic bodies with a mounting bracket, and the fixing means includes the pressing plate and the mounting bracket. A fastening member for fastening the first and second elastic bodies, and a spacer provided between the mounting bracket and the pressing plate for adjusting the fastening force of the fastening member with respect to the first and second elastic bodies. The hydraulic pulsation reducing device according to claim 1 or 2, wherein the hydraulic pulsation reducing device comprises: 4. A branching block is provided on the discharge side of the hydraulic pump, and the branching block is connected to the hydraulic pipe and to the proximal end side of the branching hose. The hydraulic pulsation reducing device described in.