Work machine

A work machine includes an engine, a fluid path via which a fuel oil is supplied to the engine, a first filter provided in the fluid path, a pump provided between the engine and the first filter in the fluid path to suck and output the fuel oil, a second filter provided between the engine and the pump in the fluid path, and a third filter provided between the engine and the second filter in the fluid path.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2016-191128, filed Sep. 29, 2016. The contents of this application are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a work machine.

Discussion of the Background

Japanese Unexamined Patent Application Publication No. 2007-162624 discloses a work machine having a filter for filtrating fuel oil.

The work machine disclosed in Japanese Unexamined Patent Application Publication No. 2007-162624 includes a pre-filter and a main filter each disposed on a pipe configured to supply fuel oil to an engine, the fuel oil being stored in a fuel tank. The pre-filter and the main filter remove impurities flowing in the pipe. In particular, Japanese Unexamined Patent Application Publication No. 2007-162624 discloses the technique that arranges an electromagnetic pump on an upper stream than the main filter and that arranges the pre-filter on an upper stream than the electromagnetic pump, the pre-filter having both of a function for separating the water and a function for removing the impurities. In this manner, the electromagnetic pump is prevented from being damaged by the impurities in the fuel oil.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a work machine includes an engine, a fluid path via which a fuel oil is supplied to the engine, a first filter provided in the fluid path, a pump provided between the engine and the first filter in the fluid path to suck and output the fuel oil, the pump provided between the engine and the first filter in the fluid path, a second filter provided between the engine and the pump in the fluid path, and a third filter provided between the engine and the second filter in the fluid path.

DESCRIPTION OF THE EMBODIMENTS

Referring to drawings, embodiments of the present invention will be explained below.

First Embodiment

Whole Configuration

FIG. 16toFIG. 18illustrate a work machine1according to one embodiment (a first embodiment) of the present invention. The embodiment exemplifies a backhoe as the work machine1. The backhoe is a swiveling work machine (or a turning work machine). However, the work machine1is not limited only to the backhoe but may be other work machines such as a tractor, a loader work machine (a compact track loader and the like).

The work machine1includes a machine body (a turning base)2, a travel device3, and an operation device4.

A cabin5is mounted on the machine body2. As shown inFIG. 17, an operator seat6is arranged in the cabin5. Hereinafter, in explanations of all the embodiments of the present invention, a forward direction (a direction shown by an arrowed line F inFIG. 18) corresponds to a front side of an operator seating on an operator seat6of the work machine1, a backward direction (a direction shown by an arrowed line R inFIG. 18) corresponds to a back side of the operator, a leftward direction (a direction vertically extending from a back surface to a front surface ofFIG. 18) corresponds to a left side of the operator, and a rightward direction (a direction vertically extending from the front surface to the back surface ofFIG. 18) corresponds to a right side of the operator.

In addition, a machine width direction corresponds to a horizontal direction K2(refer toFIG. 17) perpendicular to a front to rear direction K1.

The travel device3is disposed on a lower portion of the machine body2. In the embodiment, the travel device3is constituted of a crawler-type travel device. However, the travel device3may be a wheel-type travel device having a front wheel and a rear wheel. A dozer device7is attached to a front portion of the travel device3. A dozer cylinder C1is capable of being stretched and shortened. The dozer device7is moved upward and downward by the stretching and shortening of the dozer cylinder C1.

The machine body2is supported on the travel device3by a turn bearing. Thus, the machine body2is capable of being turned about a perpendicular axis (a vertical axis) of the turn bearing. The machine body2is turned by a turn motor MT. The machine body2includes a base plate (a turn base plate)9and a weight10. The base plate9is configured to turn about the vertical axis. The weight10is arranged to balance the weight of the work machine1against the operation device4. The weight10is disposed on the rear portion of the machine body2.

A support bracket13is included on the front portion of the machine body2. A swing bracket14is attached to the support bracket13. Thus, the swing bracket14is capable of being swung about the vertical axis. The operation device4is attached to the swing bracket14.

The operation device4includes a boom15, an arm16, and a bucket17. A base portion of the boom15is pivotally attached to the swing bracket14. Thus, the base portion of the boom15is capable of being turned about a horizontal axis, and thereby the boom15is capable of being swung upward and downward. The arm16is pivotally attached to a tip end portion of the boom15. Thus, the arm16is capable of being turned about the horizontal axis and thereby being swung forward and backward. The bucket17is disposed on a tip end portion of the arm16. Thus, the bucket17is capable of shoveling and dumping.

A swing cylinder C2is capable of being stretched and shortened. The swing bracket14is swung by the stretching and shortening of the swing cylinder C2. A boom cylinder C3is capable of being stretched and shortened. The boom15is swung by the stretching and shortening of the boom cylinder C3. An arm cylinder C4is capable of being stretched and shortened. The arm16is swung by the stretching and shortening of the aim cylinder C4. A bucket cylinder C5is capable of being stretched and shortened. The bucket17shovels and dumps due to the stretching and shortening of the bucket cylinder C5.

As shown inFIG. 17, an engine room ER is disposed on the rear portion of the machine body2. An engine E is arranged in the engine room ER. The engine E is a diesel engine, for example, a diesel engine (a common-rail type engine) having a common-rail fuel injection system (CRS).

The common-rail type engine includes a fuel pressuring-supplying pump (a supply pump), a common-rail (a pressure accumulation chamber), and an injector. The fuel pressuring-supplying pump generates a highly-pressured fuel. The common-rail accumulates the highly-pressured fuel generated by the fuel pump. The injector injects the highly-pressured fuel to each of cylinders of the engine E under the control by an ECU, the highly-pressured fuel being accumulated in the common-rail.

A radiator18, a fuel oil cooler19, and a fuel pump20are arranged on the right side of the engine E. A hydraulic pump21is arranged on the left side of the engine E.

A tank room TR is disposed on a right portion of the machine body2. An operation fluid tank22is arranged in the tank room TR. The operation fluid tank22stores the operation fluid that is to be supplied to the hydraulic devices. The operation fluid stored in the operation fluid tank22is supplied to the hydraulic devices by the hydraulic pump21.

A fuel tank23is arranged in front of the operation fluid tank22. The fuel tank23stores the fuel oil that is to be supplied to the engine E. The fuel oil stored in the fuel tank23is supplied to the engine E by the fuel pump20.

A first filter61is arranged in the vicinity of the operation fluid tank22. A second filter62and a third filter63are arranged behind the engine E. The first filter61, the second filter62, and the third filter63constitute a fuel filtration device60. The fuel filtration device60will be explained below.

As shown inFIG. 16, an upper portion of the machine body2is covered with a cover. The cover includes a first cover25, a second cover26, a third cover27, a fourth cover28, a fifth cover29, and a sixth cover30.

The first cover25covers an upper surface of the rear portion of the engine room ER. Hereinafter, the first cover25is referred to as “the bonnet25”. The bonnet25is capable of being opened and closed turning about a support shaft (described later) disposed in front of the bonnet25, and thus covers the upper surface of the engine E when the bonnet25is closed.

As shown inFIG. 18, a latch25ais attached to a rear lower portion of the bonnet25. The latch25ais latched to a receiving shaft811of a first bracket81when the bonnet25is closed. The first bracket81will be described later. The second cover26covers an upper surface of a right front portion of the engine room ER. The third cover27covers an upper surface of the tank room TR.

The fourth cover28covers a right side surface of the tank room TR. The fifth cover29is disposed between the cabin5and the third cover27. The sixth cover30is disposed in front of the fifth cover29.

As shown inFIG. 1, an upper structural body is disposed on the base plate9. The upper structural body includes vertical ribs (a first vertical rib31and a second vertical rib32), partition plates (a first partition plate35and a second partition plate36), a rear portion frame37, and a rear support member41. The upper structural body is integrated with the base plate9by the welding, and thus the upper structural body and the base plate9constitute a turn frame.

The first vertical rib31extends backward from the front on the base plate9, the first vertical rib31passing through a turn center of the machine body3. The second vertical rib32extends backward from the front on the base plate9, the second vertical rib32being arranged to the right of the first vertical rib31. The support bracket13is disposed between a front portion of the first vertical rib31and a front portion of the second vertical rib32. A support plate38bridges a space between an upper portion of the first vertical rib31and an upper portion of the second vertical rib32.

The first partition plate35is arranged in front of the engine room ER, and the first partition plate35extends toward the machine width direction. The second partition plate36extends leftward from the left side of the first partition plate35. The rear portion frame37is disposed on a rear portion of the base plate9and extends in the machine width direction.

The rear support member41stands at a center of the rear portion of the base plate9in the machine width direction. The rear support member41is connected to a rear portion of the rear portion frame37. The weight10is attached by fastening members (bolts) to the rear portion of the rear portion frame37and to a rear portion of the rear support member41.

The upper structural body further includes a cabin support member43, a lateral plate44, support stays45R and45L, and a left support member46.

The cabin support member43supports the cabin3with a mount member (an anti-vibration rubber and the like) sandwiched between the cabin3and the cabin support member43. The lateral plate44is connected to a rear surface of the first partition plate35. The lateral plate includes a right support portion44R and a left support portion44L. The right support portion44R and the left support portion44L supports a front portion of the engine E with a mount member sandwiched between the engine E and the right support portion44R and the left support portion44L. The support stay45R stands on a right upper portion of the rear portion frame37.

The support stay45L stands on a left upper portion of the rear portion frame37. The support stay45R and the support stay45L support a rear portion of the engine E with a mount member sandwiched between the engine E and the support stays45R and45L. The left support member46is disposed on a left portion of the base plate9. The left support member46is connected to a left portion of the second partition plate36. The left support member46supports a leg51(a first leg51) of a support frame50. The support frame50will be explained below.

The support frame50is disposed on the base plate9. The support frame50supports the covers mentioned above (the first cover (the bonnet)25to the sixth cover30). The support frame50includes the leg51, a leg52(a second leg52), a first support portion53, and a second support portion54.

The leg51(the first leg51) stands on one of sides (on the left side) of the base plate9in a width direction of the base plate9(the width direction being identical to the machine width direction). The leg52(the second leg52) stands to the right of the leg51.

The leg52includes a support pole52A and a communicating portion52B. A lower portion of the support pole52A is fixed by a bolt to a rear portion of an upper surface of the support plate38. The lower portion of the support pole52A extends upward from the upper surface of the support plate38. The communicating portion52B is disposed on the support pole52A and extends backward from an upper portion of the support pole52A.

The first support portion53is disposed on one of sides (on the left side) of the base plate9in the width direction of the base plate9. The first support portion53extends along the machine width direction, and connects an upper portion of the leg51to an upper portion of the leg52. The first support portion53supports the rear portion of the cabin3with a mount member (an anti-vibration rubber and the like) sandwiched between the cabin3and the first support member53.

The second support portion54is disposed on the other one of the sides (on the right side) of the base plate9in the width direction of the base plate9. The second support portion54supports the second cover26. The second support portion54includes a front member54A and a rear member54B. The front member54A extends from the communicating portion52B toward the machine width direction (the right direction). The rear member54B extends from the communicating portion52B toward the machine width direction (the right direction).

A support shaft (not shown in the drawings) is disposed on a rear portion of the first support portion53and on a rear portion of the second support portion54(the rear member54B). A front portion of the bonnet25is attached to the support shaft. The bonnet25turns about an axis of the support shaft, and thereby is capable of being opened and closed.

Fuel Filtration Device

As shown inFIG. 8,FIG. 17, and the like, the work machine1according to the embodiment includes the fuel filtration device60. The fuel filtration device60removes impurities included in the fuel oil that is to be supplied to the engine E. The fuel filtration device60includes the first filter61, the second filter62, and the third filter63.

The first filter61is a sedimenter to remove water included in the fuel oil that is to be supplied to the engine E. An inlet of the first filter61is connected to the tank (the fuel tank)23by a first fluid tube (a first fluid path)71. An outlet of the first filter61is connected to a suction port of the pump (the fuel pump)20by a second fluid tube (a second fluid path)72.

The first filter61separates the water included in the fuel oil from the fuel oil due to a difference between a specific weight of the water and a specific weight of the fuel oil, the fuel oil being to be supplied from the fuel tank23to the engine E. In addition, the first filter61may have a function to remove a foreign substance and the like included in the fuel oil.

The second filter62is a filter of a filtration type (a screen type). The second filter62removes the water and the impurities (the foreign substance such as particulates) both included in the fuel oil that is to be supplied to the engine E. An inlet of the second filter62is connected to an output port of the fuel pump20by a third fluid tube (a third fluid path)73.

An outlet of the second filter62is connected to the third filter63by a fourth fluid tube (a fourth fluid path)74. The fluid pump20sucks the fuel oil that passes through the first filter61and supplies the fuel oil to the second fluid tube72, and then outputs the fuel oil to the third fluid tube73.

The second filter62filtrates the fuel oil that is outputted from the fuel pump20to the third fluid tube73, and then supplies the fuel oil to the fourth fluid tube74. As shown inFIG. 5and the like, the second filter62includes a main body, a water detection sensor64, and a heater65. The main body includes a housing62aand a lid member62b.

The housing62ahas a cylindrical shape having an opening upper surface. A filter element (a filtration member) is housed in the housing62a. The filter element catches the impurities (the foreign substance such as particulates) included in the fuel oil. A water drain tube (a water drain path)77is connected to a lower portion of the housing62a.

The lid62bis attached to an upper portion of the housing62aso as to close the upper surface of the housing62a. The lid62bhas an inlet port and an outlet port. The inlet port of the lid62bis connected to the third fluid tube73. The outlet port of the lid62bis connected to the fourth fluid tube74.

The water detection sensor64is attached to a lower portion of the housing62a. The water detection sensor64detects the water included in the fuel oil. In particular, the water detection sensor64detects the water collected in the lower portion of the housing62a, the water being separated from the fuel oil due to a difference between a specific weight of the water and a specific weight of the fuel oil.

The water collected in the lower portion of the housing62ais detected by the water detection sensor64, and can be manually discharged to a drain through the water drain tube77. In this manner, when the first filter61does not remove the water sufficiently, the second filter62separates the water included in the fuel oil, detects an amount the water separated from the fuel oil, removes the water as needed, and then supplies the fuel oil to the third filter63.

In this manner, the fuel oil including little amount of the water can be supplied to the engine E.

The heater65is activated when a temperature of the fuel oil is a predetermined temperature or less, and thus warms the fuel oil. In this manner, the fuel oil is prevented from being turned into a wax state (being solidified), and thus the third filter63is prevented from being filled with the fuel oil solidified as mentioned above even when the third filter63employs a filter having a filtration fineness higher than the filtration fineness of the second filter62as described below. Thus, the fuel oil can be supplied to the engine E adequately.

The third filter63is a filter of a filtration type (a screen type) as with the second filter62. The third filter63removes the impurities (the foreign substance such as particulates) included in the fuel oil that is to be supplied to the engine E. The third filter63filtrates the fuel oil that is outputted to the fourth fluid tube74after passing through the second filter62, and then outputs the fuel oil to a fifth fluid tube (a fifth fluid path)75.

An inlet of the third filter63is connected to an outlet of the second filter62by the fourth fluid tube74. An outlet of the third filter63is connected to the engine E by the fifth fluid tube75.

As shown inFIG. 6, the third filter63includes a housing63aand a lid member63b. The housing63ahas a cylindrical shape having an opening upper surface. A filter element (a filtration member) is housed in the housing63a. The filter element catches the impurities (the foreign substance such as particulates) included in the fuel oil.

The lid63bhas an inlet port and an outlet port. The inlet port of the lid63bis connected to the fourth fluid tube74. The outlet port of the lid63bis connected to the fifth fluid tube75. In addition, an air release tube78is connected to the lid63b.

The third filter63has a filtration fineness higher than the filtration fineness of the second filter62. In other words, the third filter63includes a filter element having a mesh size smaller than a mesh size of a filter element of the second filter62. That is, in the embodiment, the filtration fineness is defined depending on the mesh size. However, the types of the filter elements of the second filter62and the third filter63are not limited to a specific type.

In addition, the third filter63has a filtration area larger than a filtration area of the second filter63. In this manner, the third filter63catches the impurities (the foreign substance such as particulates) that passes through the second filter62(that is not caught by the second filter62). A capacity of the third filter63(a capacity of the housing63a) may be set to be larger than a capacity of the second filter62(a capacity of the housing62a).

In this manner, while the third filter63tends to be clogged due to the small mesh size, the third filter63having the large capacity can be exchanged in a cycle similar to a cycle of exchanging the second filter62.

The second filter62and the third filter63both have the filtration fineness suppressing an amount of the impurities that are included in the fuel oil filtrated by the second filter62and the third filter63such that the amount of the impurities can be an allowable amount or less preliminarily determined for the common-rail engine E (for example, an allowable amount or less set on the basis of the specifications that is determined by an manufacturer of the common-rail engine E).

In this manner, the engine E receives the fuel oil having the high cleanness even in a case where the fuel oil filled in the fuel tank23has a relatively-low cleanness for example. In particular, the common-rail type engine tends to cause a trouble where the common rail is clogged by the impurities included in the fuel oil, and thus it is required to supply the fuel oil having the high cleanness with respect to the engines of other types. However, the second filter62and the third filter63according to the embodiment keep the high cleanness of the fuel oil that is to be supplied to the engine E, thereby preventing the troubles mentioned above.

Meanwhile, in a case where the fuel oil filled in the fuel tank23has a relatively-high cleanness, the second filter62and the third filter63each are solely capable of suppressing the amount of the impurities such that the amount of the impurities can be an allowable amount or less preliminarily determined for the common-rail engine E, the impurities being included in the fuel oil filtrated by the second filter62or the third filter63.

Thus, the work machine1may employ both the second filter62and the third filter63and may employ only the second filter62without employing the third filter63on the basis of the cleanness and the like of the fuel oil distributed in a region where the work machine1is used.

Among the second filter62and the third filter63, the third filter63is provided with an air release mechanism. That is, in the embodiment, the second filter62is not provided with the air release mechanism, but the third filter63is provided with the air release mechanism

The air release mechanism removes air present in the fuel oil that flows into the third filter63. As shown inFIG. 8, the air release mechanism includes an air release tube (an air release path)78and a valve79. The air release tube78connects the third filter63to a sixth fluid tube (a sixth fluid path)76described below. The valve79is disposed on an intermediate portion of the air release tube78.

In the embodiment, the third filter63is not provided with the water detection sensor and the heater. However, the third filter63may have a configuration having the water detection sensor and/or the heater similar to the water detection sensor and/or the heater of the second filter62.

The sixth fluid tube76connects the fuel tank23to the engine E. The fuel oil cooler19is disposed on an intermediate portion of the sixth fluid tube76. The fuel oil cooler19cools the fuel oil flowing in the sixth fluid tube76. The fuel oil supplied from the engine E to the sixth fluid tube76is cooled by the fuel oil cooler19, and then returns to the fuel tank23.

The fuel oil returned to the fuel tank23is sucked by the fuel pump20, and is supplied to the first filter61again through the first fluid tube71.

The air release tube78is connected to an intermediate portion of the sixth fluid tube76(between the engine E and the fuel oil cooler19). When the valve79of the air release mechanism is opened, the valve79releases the air present in the fuel oil to the sixth fluid tube76through the air release tube78, the fuel oil flowing into the third filter63.

The first fluid71to the sixth fluid tube76, the water drain tube77, and the air release tube78are constituted of tube materials such as hoses and pipes.

Filter Support Structure

As shown inFIG. 17, the second filter62and the third filter63are arranged in the rear portion of the engine room ER (arranged behind the engine E). Referring toFIG. 2toFIG. 7, support structures for the second filter62and the third filter63will be explained below.FIG. 3illustrates the weight10using the vertical lines (the two-dot chain lines).

The second filter62is supported by a support bracket80. As shown inFIG. 5andFIG. 6, the support bracket80includes a fixing portion80a, an extending portion80b, and a supporting portion80c.

The fixing portion80ahas a plate shape and includes a through hole80d. The fixing portion80ais fixed to an upper surface of the rear support member41by a bolt (not shown in the drawings) inserted into the through hole80d. The extending portion80bis extended forward and leftward from the left end of the fixing portion80a.

The extending portion80bis provided with through holes through which the water drain tube77and wirings of the water detection sensor64, the water drain tube77being connected to the second filter62. The supporting portion80cis extended upward from an end of the extension of the extending portion80b. The supporting portion80cis formed to have a plate shape, and is arranged facing one of the surfaces a right-forward direction and facing the other one of the surfaces in a right-backward direction.

An attachment hole80eis disposed on an upper portion of the supporting portion80c. The second filter62is attached to one side surface of the supporting portion81cby a bolt (not shown in the drawings) inserted into the attachment hole80e. The second filter62supported by the supporting bracket80is positioned leftward in front of an attachment portion83disposed on the weight10.

The third filter63is supported by a support mechanism. The support mechanism includes the first bracket81, a second bracket82, and the attachment portion83.

The first bracket81is a member configured to receive (latch) the bonnet25when the bonnet25is closed. As shown inFIG. 6and the like, the first bracket81includes the receiving shaft811and a support member812.

The receiving shaft811extends toward the machine width direction, and latches the latch25adisposed on a rear lower portion of the bonnet25. The latch25ais latched to the receiving shaft811(the bonnet25is received by the first bracket81) when the bonnet25is closed, and thereby the bonnet25is held under the closed state. Releasing the latching between the receiving shaft811and the latch25aof the bonnet25, the bonnet25can be opened upward.

The support member812includes a lower plate812aand a side plate812b. The lower plate812ahas a plurality of through holes812c(two through holes812c) arranged in the machine width direction. The side plate812bstands up from one of edges (a right edge) of the lower plate812ain the machine width direction. Another side plate812bstands up from the other one of the edges (a left edge) of the lower plate812ain the machine width direction. In this manner, the side plates812bsupport both of end portions of the receiving shaft811.

The attachment portion83is a portion to which the first bracket81is attached. The attachment portion83is disposed on a front surface of the weight10at a center of the weight10in the machine width direction, and the attachment portion83projects forward from an upper portion of the front surface.

As shown inFIG. 18, the attachment portion83is positioned behind the engine E. As shown inFIG. 6, the attachment portion83has an upper surface83a. The upper surface83ais substantially horizontal. And, the lower plate812aof the first bracket81is attached to the upper surface83a. The attachment portion83has an attachment hole (a screw hole)83bthat is formed downward from the upper surface83aof the attachment portion83.

The attachment portion83has a plurality of the attachment holes83b(two attachment holes83b) that are arranged at intervals in the machine width direction. The number of the attachment holes83band the intervals between the attachment holes83bcorrespond to the number of the through holes812cand intervals between the through holes812c, the through holes812cbeing disposed on the lower plate812aof the first bracket81.

The second bracket82is a member having a plate shape, and is configured to support the third filter63. The second bracket82is attached to the attachment portion83.

As shown inFIG. 6,FIG. 7A, andFIG. 7B, the second bracket82includes an intermediate portion82aand a support portion82b. The intermediate portion82ahas a substantially-rectangular shape in a plane view, the substantially-rectangular shape being elongated in the machine width direction. The intermediate portion82ahas a plurality of through holes82c(two through holes82c) arranged at intervals in the machine width direction. The support portion82bhas a substantially-rectangular shape in a plane view, the substantially-rectangular shape being elongated in the front to rear direction K1. The support portion82bhas a plurality of through holes82d(two through holes82d) arranged at intervals in the front to rear direction K1.

A nut (not shown in the drawings) is welded to a lower surface of the support portion82bsuch that the nut is concentric with the through hole82d. The intermediate portion82aand the support portion82bare connected to each other with a connection between one corner of the intermediate portion82aand one corner of the support portion82b. In this manner, the second bracket82has a substantially-L shape in a plane view as a whole.

In other words, the second bracket82has a shape removing two notched portions (a first notched portion82eand a second notched portion82f) from a rectangular shape in a plane view. The two notched portions are positioned on a diagonal line of the rectangular shape.

The first notched portion82eis employed for preventing interference between a support member55and the second bracket82in a case where the work machine1according to the embodiment (the first embodiment) employs the support member55that is to be described in a second embodiment of the present invention (refer toFIG. 12).

The second notched portion82fis employed for preventing interference between the second bracket82and a noise absorbing material such as a sponge (not shown in the drawings) attached to a front surface (an inner surface) of the weight10.

As shown inFIG. 7AandFIG. 7B, a rib82gis disposed on a lower surface of the second bracket82along an edge of one of the notched portions (an edge of the first notched portion82e). The rib82gis formed to have an L-shape extending from the intermediate portion82ato the support portion82bin a plane view.

To be detailed, the rib82gis formed along the first notched portion82eon a substantially full length (a half of length or more) of one of the longitudinal sides of the intermediate portion82aand on a substantially full length (a half of length or more) of one of the longitudinal sides of the support portion82b. The rib82gprotrudes downward.

The provision of the rib82gimproves the strength (the rigidity) of the second bracket82. Thus, the thickness of the second bracket82can be reduced.

As shown inFIG. 6and the like, the intermediate portion82ais arranged between the upper surface83aof the attachment portion83and the lower plate812aof the first bracket81. The through hole82c, the through hole812c, and the attachment hole83bare overlapped each other when the intermediate portion82ais arranged between the attachment portion83and the first bracket81.

In this manner, when a fastening member (a bolt) B1is inserted into the through hole82cand the through hole812cand then is screwed with attachment hole83b, the intermediate portion82ais attached being arranged (sandwiched) between the attachment portion83and the first bracket81.

That is, the intermediate portion82ais fastened to the attachment portion83together with the first bracket81by the fastening member (the bolt) B1, and is thereby attached to the attachment portion83.

In this manner, the second bracket82has a function of a shim (a spacer) for adjusting a clearance between the first bracket81and the attachment portion83in addition to a function of a bracket for supporting the third filter63. The attachment hole83bof the attachment portion83can be used for both of the attachment of the first bracket81and the attachment of the second bracket82.

Thus, the attachment of the second bracket82requires no attachment hole other than the attachment hole83b. However, the second bracket82may require an attachment hole other than the attachment hole83bof the weight10, which is a modified example of the embodiment.

In addition, a thin plate (a shim)84may be arranged between the intermediate portion82aand the attachment portion83, the thin plate84being employed for adjusting the clearance between the intermediate portion82aand the attachment portion83.

The support portion82bis a portion for supporting the third filter63. As shown inFIG. 5, the support portion82bprojects forward and rightward from the attachment portion83under the state where the intermediate portion82ais attached to the attachment portion83.

As shown inFIG. 6andFIG. 4, a fastening member (a bolt) B2is inserted into the through hole82dof the support portion82b. The bolt B2is screwed into the nut disposed on a lower surface of the support portion82b, and thereby the third filter63is attached to the support portion82b. In this manner, the third filter63is supported by the second bracket82rightward in front of the attachment portion83.

As shown inFIG. 3, the second bracket82supports the third filter63at a position where a connecting portion between the third filter63and the fourth fluid tube74(an upper surface of the housing63a) can be positioned at a height substantially identical to a height of a connecting portion between the second filter62and the air release tube78(an upper surface of the housing62a).

In this manner, the air can be prevented from staying in the second filter62without the air release mechanism employed in the second filter62, and thus the air can be released adequately from the second filter62and the third filter63.

In addition, it is possible to shorten a length of the hose (the fourth fluid tube74) connecting the second filter62to the third filter63. Moreover, the fuel oil can be supplied smoothly in comparison with the smoothness of a case where the height of the second filter62is largely different from the height of the third filter63is large.

The filter support structure described in the above-mentioned embodiment (the first embodiment) arranges the second filter62on one of the sides of (leftward in front of) the attachment portion83and arranges the third filter63on the other one of the sides of (rightward in front of) the attachment portion83.

That is, the second filter62and the third filter63are arranged adjacent to each other across the attachment portion83in the machine width direction. In this manner, a size of the filter support structure can be reduced, thereby increasing largely a space for installing the engine E.

In addition, when the bonnet25is opened, the second filter62and the third filter63can be easily accessed, and thus the easy access makes the maintenance operations easy, for example, replacement of the filter element.

Second Embodiment

Referring toFIG. 9toFIG. 13, a second embodiment of the present invention (the work machine1) will be explained below. The second embodiment mainly explains configurations different from the configurations of the first embodiment described above. The explanation of the configurations similar to the configurations of the first embodiment will be omitted except the configurations especially required to be explained.

As shown inFIG. 9, the work machine1according to the second embodiment includes the support frame50having a support member (a reinforcement leg)55in addition to the first leg51, the second leg52, the first support portion53, and the second support portion54. The support member55supports the support frame50from behind, and thereby reinforces the support frame50. The support member55supports the bonnet25from below.

The support member (the reinforcement leg)55stands on the rear portion of the engine room ER. In particular, the support member55includes a rear leg portion55aand a forward-extending portion55b. The rear leg portion55ais fixed to an upper surface of the rear support member41by a bolt, and extends upward from the upper surface.

The forward-extending portion55bis curved from an upper portion of the rear leg portion55a, and then passes above the engine E and extends forward to the support frame50. A first connection plate58is disposed on a front end of the forward-extending portion55b.

In addition, a second connection plate59is disposed on a rear end of the second leg52(the communicating portion52B) of the support frame50. The first connection plate58and the second connection plate59are connected to each other by a fastening member such as a bolt.

In this manner, the support member55is attached to the rear portion of the support frame50, and thus the support frame50is reinforced by the support member55. The support member55may be preliminarily attached to the support frame50as shown inFIG. 9, and may be attached later to the support frame50of a work machine (the work machine1according to the first embodiment and the like) that does not have the support member55.

The second filter62is supported by the third bracket85. As shown inFIG. 11,FIG. 12, and the like, the third bracket85is formed of a strip-shaped flat plate that is bent to have an L-shape. The third bracket85includes a fixation portion85aand a support portion85b.

The fixation portion85ais fixed to the rear leg portion55aof the support member55by the welding. The fixation portion85aextends forward and leftward from the rear leg portion55a. The support portion85bextends downward from an end of the extension of the fixation portion85a.

The support portion85bis arranged facing one of the surfaces a left-forward direction and facing the other one of the surfaces a right-backward direction. An attachment hole is disposed on a lower portion of the support portion85b. The second filter62is attached to one of side surfaces of the support portion80bby a bolt inserted into the attachment hole of the support portion85b. In this manner, the second filter62is supported by the third bracket85on the left of the rear leg portion55a.

The support mechanism for the third filter63is similar to the support mechanism of the third filter63according to the first embodiment mentioned above. In particular, the support mechanism for the third filter63includes the first bracket81, the second bracket82, and the attachment portion83that are similar to those of the support mechanism according to the first embodiment. The third filter63is supported by the second bracket82on the right of the rear leg portion55a.

In the second embodiment, an edge of one of the notched portions (the first notched portion82e) of the second bracket82extends along an outer surface (a rear surface and a right surface) of the rear leg portion55aof the support member55as shown inFIG. 13. In particular, the second bracket82has an edge (the edge of the first notched portion82e) formed by being notched to have a shape corresponding to an outer surface of the rear leg portion55aalong the outer surface of the rear leg portion55aof the support member55.

The second bracket82is arranged such that the first notched portion82eis opposed to the outer surface of the support member55at a predetermined interval. In this manner, the rear leg portion55aof the support member55can be prevented from interference with the second bracket82. Thus, the second bracket82does not interfere with the attachment of the support member55in a case where the support member55is attached for the reinforcement to a work machine (for example, the work machine1according to the first embodiment) that does not have the support member55.

In addition, the rib82gis disposed along an edge of one of the notched portions (the first notched portion82e) as in the first embodiment mentioned above. In this manner, even when the second bracket82forms the notched portion, the second bracket82is prevented from decreasing the strength of the second bracket82.

As shown inFIG. 11, the second bracket82supports the third filter63at a position where a connecting portion between the third filter63and the fourth fluid tube74(an upper surface of the housing63a) can be positioned at a height substantially identical to a height of a connecting portion between the second filter62and the air release tube78(an upper surface of the housing62a).

In this manner, the air can be prevented from staying in the second filter62without the air release mechanism employed in the second filter62, and thus the air can be released adequately from the second filter62and the third filter63.

In addition, it is possible to shorten a length of the hose (the fourth fluid tube74) connecting the second filter62to the third filter63. Moreover, the fuel oil can be supplied smoothly in comparison with the smoothness of a case where the height of the second filter62is largely different from the height of the third filter63is large.

The filter support structure described in the above-mentioned embodiment (the second embodiment) arranges the second filter62on one of the sides of (on the left of) the support member55(the rear leg portion55a) and arranges the third filter63on the other one of the sides of (on the right of) the support member55(the rear leg portion55a).

That is, the second filter62and the third filter63are arranged adjacent to each other across the support member55(the rear leg portion55a) in the machine width direction. In this manner, a size of the filter support structure can be reduced, thereby increasing largely a space for installing the engine E.

In addition, when the bonnet25is opened, the second filter62and the third filter63can be easily accessed, and thus the easy access makes the maintenance operations easy, for example, replacement of the filter element.

Third Embodiment

Referring toFIG. 14andFIG. 15, a third embodiment of the present invention (the work machine1) will be explained below. The third embodiment mainly explains configurations different from the configurations of the second embodiment described above. The explanation of the configurations similar to the configurations of the second embodiment will be omitted except the configurations especially required to be explained.

The work machine1according to the third embodiment has a support mechanism for the second filter62, the support mechanism being similar to the support mechanism according to the second embodiment. The second filter62is supported by the third bracket85on the left of the rear leg portion55aof the support member55.

The work machine1according to the third embodiment has a support mechanism for the third filter63different from the support mechanisms according to the first embodiment and the second embodiment.

The third filter63is supported by the fourth bracket86. The fourth bracket86is attached to a side of the support member55, the side being opposite to the third bracket85. In particular, the third bracket85is attached to one of the sides of (to the left of) the support member55(the rear leg portion55a), and the fourth bracket86is attached to the other one of the sides of (to the right of) the support member55(the rear leg portion55a).

The fourth bracket86has a flat plate shape, and includes a fixation portion86aand a support portion86b. The fixation portion86ais fixed to an outer surface of the rear leg portion55aof the support member55by the welding. The fourth bracket86extends backward and rightward from the rear leg portion55a. The support portion86bis arranged on the right of the rear leg portion55a.

The support portion86bis provided with an attachment hole. The third filter63is attached below the support portion86bby a bolt B3inserted into the attachment hole of the support portion86b. In this manner, the third filter63is supported by the fourth bracket86on the right of the rear leg portion55a.

The fourth bracket86supports the third filter63at a position where a connecting portion between the third filter63and the fourth fluid tube74(an upper surface of the housing63a) can be positioned at a height substantially identical to a height of a connecting portion between the second filter62and the air release tube78(an upper surface of the housing62a).

In this manner, the air can be prevented from staying in the second filter62without the air release mechanism employed in the second filter62, and thus the air can be released adequately from the second filter62and the third filter63.

In addition, it is possible to shorten a length of the hose (the fourth fluid tube74) connecting the second filter62to the third filter63. Moreover, the fuel oil can be supplied smoothly in comparison with the smoothness of a case where the height of the second filter62is largely different from the height of the third filter63is large.

The filter support structure described in the above-mentioned embodiment (the third embodiment) arranges the second filter62on one of the sides of (on the left of) the support member55(the rear leg portion55a) and arranges the third filter63on the other one of the sides of (on the right of) the support member55(the rear leg portion55a). That is, the second filter62and the third filter63are arranged adjacent to each other across the support member55(the rear leg portion55a) in the machine width direction.

In this manner, a size of the filter support structure can be reduced, thereby increasing largely a space for installing the engine E. In addition, when the bonnet25is opened, the second filter62and the third filter63can be easily accessed, and thus the easy access makes the maintenance operations easy, for example, replacement of the filter element.

In the above description, the embodiment of the present invention has been explained. However, all the features of the embodiment disclosed in this application should be considered just as examples, and the embodiment does not restrict the present invention accordingly. A scope of the present invention is shown not in the above-described embodiment but in claims, and is intended to include all modifications within and equivalent to a scope of the claims.