CN113226902A

CN113226902A - Construction machine

Info

Publication number: CN113226902A
Application number: CN202080007494.XA
Authority: CN
Inventors: 关口良明; 安田有多贺; 清水胜美; 田边慎一
Original assignee: Hitachi Construction Machinery Co Ltd
Current assignee: Hitachi Construction Machinery Co Ltd
Priority date: 2019-03-22
Filing date: 2020-02-17
Publication date: 2021-08-06
Anticipated expiration: 2040-02-17
Also published as: KR102466125B1; JP7016828B2; CN113226902B; WO2020195315A1; KR20210103535A; JP2020152334A

Abstract

The invention provides a construction machine, which supports an idler wheel (3b) of a crawler belt (3) in a manner of moving along the front-back direction through a yoke (28), connects a cylinder component (36) of an auxiliary cylinder (30) with the yoke (28) through a compression spring (41), and makes the bias force of the compression spring (41) act on the idler wheel (3b) corresponding to the expansion and contraction of the auxiliary cylinder (30) so as to adjust the tension of the crawler belt (3 e). A cylinder housing (43) which can expand and contract while keeping oil-tight inside and outside is constituted by a front housing member (44) fixed to a yoke (28) and a rear housing member (45) fixed to a cylinder member (36) of an auxiliary cylinder (30), a compression spring (41) is housed in the cylinder housing and grease (50) is sealed in the cylinder housing, an air hole (48) is provided through the upper portion of the cylinder housing (43), and the air hole (48) is closed by a waterproof fiber sheet (49).

Description

Construction machine

Technical Field

The present invention relates to a construction machine including a crawler portion.

Background

For example, a construction machine such as a hydraulic excavator or a bulldozer includes a pair of left and right crawler units, and each crawler unit is configured by winding a crawler belt formed in an endless shape around a drive sprocket, an idler pulley, a crawler idler wheel, and a carrier roller. The crawler belt is driven by a drive sprocket to run the construction machine, and gradually wears and reduces tension along with running of the crawler belt. Therefore, the tension adjusting operation is periodically performed by the crawler adjusting device.

For example, the crawler belt adjusting device is configured by coupling an auxiliary cylinder to an idler wheel via a compression spring, and adjusts the tension of the crawler belt by increasing or decreasing the amount of grease supplied to the grease in the auxiliary cylinder and applying the biasing force of the compression spring to the idler wheel.

During operation of the construction machine, wind and rain including muddy water and salt may act on the compression spring of the track-adjusting device, and these components may be corroded and damaged. As a countermeasure, in the technique described in patent document 1, the compression spring of the crawler belt adjusting device is covered with the bellows member, thereby preventing muddy water, salt, and the like from entering the inside.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Hei-3-59288

Disclosure of Invention

Problems to be solved by the invention

However, when the crawler belt adjusting apparatus is assembled, air is enclosed in the bellows member together with the compression spring, and the compression spring is corroded due to moisture contained in the air. Further, since the bellows member is required to have flexibility that allows expansion and contraction of the compression spring, it is manufactured using a material having not so high strength, such as rubber. Therefore, during operation of the construction machine, the construction machine may be broken by contact with crushed stones or the like, and in this case, the function of preventing intrusion of muddy water, salt, or the like is impaired. Thus, there is still room for improvement in preventing corrosion of the compression spring.

Further, since the bellows member has flexibility, a function of protecting the compression spring cannot be expected at all. This is because the bellows member is likely to be deflected when it comes into contact with a crushed stone or the like, and the crushed stone or the like collides with the compression spring.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a construction machine capable of preventing corrosion of a compression spring of a track adjustment device due to muddy water, salt, or the like, and damage due to collision of crushed stones or the like from occurring.

Means for solving the problems

In order to achieve the above object, a construction machine according to the present invention is a construction machine in which a crawler belt formed in an endless shape is wound and suspended between a drive sprocket and an idler pulley to form a crawler belt portion, a movable member of an auxiliary cylinder is connected to a yoke that movably supports the idler pulley in a front-rear direction via a compression spring, biasing force of the compression spring acts on the idler pulley in accordance with expansion and contraction of the auxiliary cylinder to adjust tension of the crawler belt, the construction machine comprising a cylinder housing capable of accommodating the auxiliary cylinder, and an air hole communicating inside and outside is provided through an upper portion of the cylinder housing, the cylinder housing comprising: a 1 st housing member fixed to the yoke; a 2 nd case member which is slidably and rotatably engaged with the 1 st case member; and a sealing member that seals the 1 st case member and the 2 nd case member.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the construction machine of the present invention, it is possible to prevent the compression spring of the track adjustment device from being corroded by muddy water, salt, or the like and being damaged by collision with crushed stones or the like.

Drawings

Fig. 1 is a side view showing a hydraulic excavator of an embodiment.

Fig. 2 is a detailed view of a portion a of fig. 1 with the side wall removed from the side frame.

Fig. 3 is a plan view corresponding to fig. 2.

Fig. 4 is a perspective view showing a support structure of the idler.

Fig. 5 is a V-V line sectional view of fig. 3 showing an internal configuration of the track adjusting device.

Fig. 6 is a sectional view taken along line VI-VI of fig. 3 showing the internal configuration of the track adjusting device.

Fig. 7 is a partially enlarged view of fig. 5 showing the air hole and the sealing member.

Detailed Description

Hereinafter, an embodiment in which the present invention is embodied in a hydraulic excavator will be described.

Fig. 1 is a side view showing a hydraulic excavator according to the present embodiment, and first, a schematic configuration of the hydraulic excavator will be described based on the drawing. In the following description, the operator riding on the hydraulic excavator mainly expresses the front-back, left-right, and up-down directions.

The lower traveling structure 2 of the hydraulic excavator 1 includes a pair of left and right crawler units 3, and each crawler unit 3 is configured by winding a crawler belt 3e formed in an endless shape around a drive sprocket 3a located on the rear side, an idler wheel 3b located on the front side, a pair of carrier rollers 3c located on the upper side, and a plurality of crawler idler wheels 3d located on the lower side. The crawler belt 3e is driven by a traveling hydraulic motor, not shown, via a drive sprocket 3a, and thereby the hydraulic excavator 1 travels.

The lower traveling structure 2 is provided with an upper revolving structure 4, and the upper revolving structure 4 is driven to revolve by a not-shown revolving hydraulic motor. An articulated work front member 5 is provided at the front portion of the upper slewing body 4, and the work front member 5 is composed of a boom 6, an arm 7, and a bucket 8. Boom 6 is changed in angle by boom cylinder 6a, arm 7 is changed in angle by arm cylinder 7a, and bucket 8 is changed in angle by bucket cylinder 8 a.

A cab 10 on which an operator rides is provided in a front portion of a frame 9 of the upper slewing body 4, and a fuel tank 11, a machine room 12, a counterweight 13, and the like are provided on the frame 9 on a rear side of the cab 10. Although not shown, an engine is mounted in the machine room 12, and the hydraulic motor for traveling or turning and the cylinders 6a to 8a are operated by supplying hydraulic oil from a hydraulic pump driven by the engine.

Fig. 2 is a detailed view of a portion a of fig. 1 with side walls removed from side frames, fig. 3 is a plan view corresponding to fig. 2, fig. 4 is a perspective view showing a support structure of an idler 3b, fig. 5 is a cross-sectional view taken along line V-V of fig. 3 showing an internal structure of a track adjusting device, and fig. 6 is a cross-sectional view taken along line VI-VI of fig. 3 showing the internal structure of the track adjusting device. In the following description, the crawler belt adjusting device 21 for adjusting the tension of the crawler belt 3e of the left crawler belt portion 3 will be described, and the right side has the same structure in bilateral symmetry.

As shown in fig. 3 and 6, the track frame 22 of the lower traveling structure 2 is formed by connecting side frames 24 to both the left and right sides of a center frame 23, and a drive sprocket 3a, an idler 3b, a carrier roller 3c, and a track roller 3d are supported by the side frames 24.

As shown in fig. 2 to 5, base ends of a pair of left and right guide rails 26 are fixed to a front wall 25 of the side frame 24, and guide grooves 27 extending in the front-rear direction are formed between a pair of upper and

lower rail members

26a, 26b constituting each guide rail 26. A pair of distal end portions 28a of a yoke 28 having a Y-shape in plan view are slidably disposed in the respective guide grooves 27 in the front-rear direction, and both ends of a shaft 29 of an idler pulley 3b disposed between the guide rails 26 are rotatably supported by the distal end portions 28a of the yoke 28. A base end portion 28b of the yoke 28 extending rearward projects into the side frame 24 through the communication hole 25a of the front wall 25 and is connected to an assist cylinder 30 of the crawler belt adjusting device 21. As shown in fig. 1, the support structure of the idler pulley 3b is covered by a side wall 31 of the side frame 24.

As shown in fig. 3 and 5, in side frame 24, assist cylinder 30 is disposed between front wall 25 and partition wall 33, and cylinder base 34 of assist cylinder 30 is fixed to partition wall 33. The proximal end of the fixed rod 35 is fixed to the cylinder base 34, and a cylinder member 36 (corresponding to a movable member of the present invention) is slidably fitted to the distal end of the fixed rod 35 directed forward, and defines a cylinder chamber 37. The cylinder chamber 37 communicates with one end of a grease hole 38 formed in the fixing rod 35, and the other end of the grease hole 38 communicates with a pipe joint 39 fixed to the outer peripheral surface of the cylinder base 34.

The movable rod 36a of the cylinder member 36 is directed forward, and the distal end thereof is inserted into a rod hole 28c provided through the base end 28b of the yoke 28, and is prevented from coming off by a nut 40 screwed from the opposite side. The auxiliary cylinder 30 is constituted by the above-described cylinder base 34, fixed rod 35, and cylinder member 36, and the compression spring 41 is disposed on the outer peripheral side of the auxiliary cylinder 30 with the axis L thereof as the center. The compression spring 41 has a tip end abutting against the flange portion 28d formed at the base end portion 28b of the yoke 28 and a rear end abutting against the flange portion 36b of the cylinder member 36. Thus, the biasing force of the compression spring 41 acts in a direction in which the sub-cylinder 30 is separated from the yoke 28, and the yoke 28 receives the biasing force and abuts against the nut 40 to restrict the forward movement.

The grease is supplied/discharged into/from the cylinder chamber 37 through the pipe joint 39, and the volume of the cylinder chamber 37 changes in accordance with the grease supply/discharge, thereby extending/contracting the auxiliary cylinder 30. Therefore, the front-rear positions of the yoke 28 and the idler pulley 3b are changed, and the biasing force of the compression spring 41 acts on the idler pulley 3b to adjust the tension of the crawler belt 3 e. When a crushed stone or the like collides with the crawler belt portion 3 while the hydraulic excavator 1 is moving forward, the rearward position of the idler pulley 3b changes, and the compression spring 41 flexes via the yoke 28 to absorb the impact.

On the other hand, the compression spring 41 of the crawler belt adjusting device 21 of the present embodiment is housed in the cylinder housing 43.

As shown in fig. 3, 5, 6, and 7, the cylinder housing 43 is formed by a front-side housing member 44 (corresponding to the 1 st housing member of the present invention) and a rear-side housing member 45 (corresponding to the 2 nd housing member of the present invention) which are formed in a bottomed cylindrical shape with the axis L of the auxiliary cylinder 30 as the center. In the present embodiment, the two

case members

44 and 45 are made of a steel plate by press forming, but the present invention is not limited thereto, and may be configured by welding, for example. The front and

rear case members

44 and 45 are disposed so that their open ends face each other, and through

holes

44b and 45b are provided through the bottom surfaces 44a and 45a, respectively.

The base end portion 28b of the yoke 28 is fitted into the through hole 44b of the front side housing member 44, and the bottom surface 44a is sandwiched between the flange portion 28d thereof and the front end of the compression spring 41, whereby the front side housing 44 is fixed to the yoke 28 and integrally changes in the front-rear direction. The cylinder member 36 is fitted into the through hole 45b of the rear side housing member 45, and the bottom surface 45a is sandwiched between the flange portion 36b and the rear end of the compression spring 41, whereby the rear side housing member 45 is fixed to the cylinder member 36 and integrally changes in the front-rear direction.

The rear housing member 45 has a diameter slightly smaller than that of the front housing member 44, and the rear housing member 45 is inserted into the front housing member 44. A seal 46 is provided on the outer peripheral surface of the open end of the rear case member 45, and the seal 46 abuts against the inner peripheral surface of the front case member 44. Further, a seal 47 is provided on the inner peripheral surface of the rod hole 28c of the yoke 28, and the seal 47 abuts on the outer peripheral surface of the movable rod portion 36 a. Thereby, the cylinder housing 43 expands and contracts in the front-rear direction, in other words, in the axial line L direction of the assist cylinder 30 while maintaining oil-tight inside and outside.

An air hole 48 is provided through the upper portion of the rear case member 45, and the air hole 48 is closed by a waterproof fiber sheet 49 adhered to the inner peripheral surface of the rear case member 45. The waterproof fiber sheet 49 is an oil absorbing member described in japanese patent No. 4053712. Therefore, the description of the material examples and properties described in this publication is also common to the waterproof fiber sheet 49 of the present embodiment. Specifically, the water-repellent fiber sheet 49 is made of one or more materials such as felt, cotton, polymer absorber, cloth, and paper, and has the characteristics of water repellency and affinity for lubricating oil. Further, as is clear from the description of the above materials, the material is fibrous and therefore has air permeability.

Further, grease 50 is sealed in the cylinder housing 43 and impregnated with the compression spring 41 therein. The amount of grease 50 enclosed was adjusted as follows: even when the cylinder housing 43 is expanded and becomes the maximum volume, a portion up to the upper portion of the compression spring 41 is immersed in the grease 50, and even when the cylinder housing 43 is contracted and becomes the minimum volume, the grease 50 does not overflow from the air hole 48. The grease 50 is used in order to obtain a high rust prevention effect by being wound around the compression spring 41 with a high viscosity, but is not limited thereto, and a grease with a lower viscosity may be used. The crawler belt adjusting device 21 described above is shielded by the side wall 51 of the side frame 24 as shown in fig. 1.

In the crawler belt adjusting device 21 of the present embodiment configured as described above, when the yoke 28 changes in the front-rear direction due to the tension adjustment of the crawler belt 3e, the collision of crushed stones, or the like with the crawler belt portion 3, it is necessary to circulate air inside and outside in accordance with the change in the volume of the cylinder housing 43. This is because, unlike the corrugated member having flexibility of patent document 1, the cylinder case 43 made of a steel plate does not flex, and expansion and contraction of the cylinder case 43 are hindered by the air inside. At this time, when the cylinder case 43 contracts, the air inside flows out through the waterproof fabric piece 49 and the air hole 48, and when the cylinder case 43 extends, the outside air flows in through the air hole 48 and the waterproof fabric piece 49. Therefore, expansion and contraction of the cylinder housing 43 and further positional change of the yoke 28 in the front-rear direction are allowed, and adjustment of the tension of the crawler 3e and impact absorption at the time of collision of rocks or the like with the crawler 3 can be normally performed.

In addition, although the waterproof fiber sheet 49 allows air to flow due to air permeability, moisture is blocked due to waterproofness, and salts and the like contained in the moisture are also blocked. During operation of the hydraulic excavator 1, wind and rain including muddy water and salt may act on the cylinder housing 43, but moisture, salt, and the like can be prevented from entering the cylinder housing 43. Further, even if moisture, salt, or the like intrudes into the cylinder housing 43, direct contact with the compression spring 41 impregnated in the grease 50 is prevented, and therefore, corrosion thereof can be prevented in advance.

Further, at the time of assembling the crawler belt adjusting device 21, the air with moisture is sealed in the cylinder case 43, but is similarly prevented from directly contacting the compression spring 41 by the grease 50, and therefore, corrosion does not occur. Further, since the strong cylinder case 43 made of steel plate is not damaged even when it comes into contact with crushed stones or the like during operation of the hydraulic excavator 1, the grease 50 continues to be impregnated into the compression spring 41 without leaking to the outside, and the effect of preventing corrosion can be reliably obtained for a long period of time.

On the other hand, since the cylinder housing 43 is protected from direct collision of crushed stones or the like with the compression spring 41, it is possible to prevent breakage thereof in advance.

In the present embodiment, since most of the auxiliary cylinder 30 is accommodated in the cylinder housing 43 in addition to the compression spring 41, the above-described effects of corrosion prevention and damage prevention can be obtained even in the accommodated portion.

Further, by impregnating the compression spring with the grease 50 in this manner, the corrosion resistance does not become a problem even if the coating of the compression spring 41, which has been conventionally performed, is omitted. Further, by omitting the painting operation, another effect of reducing the manufacturing cost of the crawler belt adjusting device 21 can also be obtained.

The embodiments have been described above, but the aspect of the present invention is not limited to the embodiments. For example, although the embodiment is described as the hydraulic excavator 1, the present invention is not limited to this and may be applied to a bulldozer, for example, if the construction machine includes the track portion 3.

In the above embodiment, the air holes 48 of the cylinder case 43 are closed with the waterproof fiber sheet 49, but the present invention is not limited thereto, and the waterproof fiber sheet 49 may be omitted. In this case as well, since the compression spring 41 of the cylinder housing 43 is impregnated with the grease 50, corrosion thereof can be prevented, and breakage thereof can be prevented by the strong cylinder housing 43.

Description of the reference numerals

1 Hydraulic digger (engineering machinery)

3a drive sprocket

3b idler

3e track

3 track part

28 yoke

30 auxiliary cylinder

36 Cylinder part (Movable part)

41 compression spring

43 cylinder shell

44 front side cylinder part (1 st shell part)

45 rear cylinder part (2 nd case part)

48 air holes

49 waterproof fiber sheet

Claims

1. A construction machine in which a crawler belt formed in an endless shape is wound and suspended between a drive sprocket and an idler wheel to form a crawler belt portion, a movable member of an auxiliary cylinder is connected to a yoke that supports the idler wheel so as to be movable in a front-rear direction via a compression spring, and a biasing force of the compression spring is applied to the idler wheel in accordance with expansion and contraction of the auxiliary cylinder to adjust a tension of the crawler belt,

a cylinder housing configured to be able to accommodate an assist cylinder, an air hole communicating inside and outside being provided through an upper portion of the cylinder housing, the cylinder housing including: a 1 st housing member fixed to the yoke; a 2 nd case member which is slidably and rotatably engaged with the 1 st case member; and a sealing member that seals the 1 st case member and the 2 nd case member.

2. The work machine of claim 1,

the air hole of the cylinder shell is sealed by a waterproof fiber sheet with waterproofness and air permeability.