JP2009113658A - Opening/closing structure for engine hood - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an opening/closing of an engine hood capable of certainly holding the engine hood even if an opening angle of the engine hood of a construction machine is made sufficiently large. <P>SOLUTION: The opening/closing structure 21 for the engine hood is an opening/closing structure for the engine hood 20 covering an upper part of an engine room 6 of a hydraulic shovel 1, and includes the engine hood 20; a gas spring 33; and maximum opening angle enlargement mechanisms (34, 35). The engine hood 20 is supported in the engine room 6 of the construction machine so as to be turnable. The gas spring 33 gives urging force to the engine hood 20 when the engine hood 20 is opened. The maximum opening angle enlargement mechanisms (34, 35) permit the opening of the engine hood 20 to be further opened from a state that the gas spring 33 is stretched to the maximum length. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an opening / closing structure of an engine hood attached so as to cover a part of an engine room that houses a power source such as an engine mounted on a construction machine such as a hydraulic excavator.

  In recent years, in construction machines, in order to block noise generated from a power chamber including a power source, a structure in which a power chamber storing these components is covered with an exterior cover is generally used.

  On the other hand, the power source in the power chamber covered by the exterior cover needs to be regularly maintained and inspected, and may require urgent maintenance. In this case, for example, it is very inefficient to perform the work by removing the exterior cover fixed to the frame by fastening members such as bolts and nuts each time, and there is a possibility that the operator may be burdened.

  Therefore, even when the maintenance of the equipment stored in the power room becomes necessary, it is attached to cover the upper surface of the exterior cover so that the maintenance inside the exterior cover can be easily performed. An open / close structure for the engine hood has been proposed.

  For example, an engine hood opening / closing structure that opens and closes an engine hood via a hinge that is pivotable about an axis that is disposed along a horizontal direction is known (see, for example, Patent Document 1).

  An engine hood opening / closing structure is also known in which a gas spring is provided as a part of the engine hood opening / closing structure in order to assist an operation performed by a person when the engine hood is opened (for example, Patent Documents). 2).

  The gas spring is a device that assists the operating force during the opening operation by the biasing force of the compressed gas in the gas spring. Also, if the reaction force of the gas spring is set large, the engine hood will not close even if a random force acts in the direction to close the engine hood. That is, the gas spring also has a function of holding the engine hood in an open state.

The gas spring is composed of a tube and a piston and a rod that are slidable in the axial direction within the tube. The tube of the gas spring is divided into two chambers by a piston, and both chambers are filled with compressed gas. Both chambers communicate with each other through an orifice, and the rod-side chamber has a smaller area for receiving gas pressure than the other chambers, so that the rod always has a repulsive force in the extending direction.
JP 2006-056326 A (published March 2, 2006) JP 2007-169926 A (published July 5, 2007)

  However, the conventional engine hood opening and closing structure has the following problems.

  Generally, a gas spring needs to be used so that a tensile force does not act in order to prevent breakage. Therefore, the engine hood of a construction machine is used so that it does not open any more before the tensile force acts on the gas spring.

  However, in order to improve maintainability in construction machines, it has been studied to further increase the opening angle of the engine hood. In this case, for example, the following problems are concerned.

  For example, if the engine hood tilts until the center of gravity of the engine hood is located on the opening side of the rotation axis of the engine hood, the gas hood will be further pulled from the maximum length state as the engine hood tries to open further by its own weight. . When such a large tensile load is applied, the gas spring is easily damaged. If the gas spring breaks, the engine hood cannot be held sufficiently.

  An object of the present invention is to provide an open / close structure of an engine hood that can reliably hold the engine hood even if the opening angle of the engine hood of the construction machine is sufficiently large.

  An engine hood opening / closing structure according to a first aspect of the present invention is an engine hood opening / closing structure that covers an upper portion of an engine room of a construction machine, and includes an engine hood, a gas spring, and a maximum opening angle expansion mechanism. The engine hood is rotatably supported in the engine room. The gas spring applies a biasing force to the engine hood when the engine hood is opened. The maximum opening angle expansion mechanism allows the engine hood to be further opened from the state in which the gas spring is extended to the maximum length.

  In this structure, the gas spring assists the operating force when the engine hood is opened. As the opening angle of the engine hood increases, the gas spring extends. When the engine hood is further opened from the state where the gas spring is extended to the maximum length, the engine hood is further opened by the maximum opening angle extending mechanism. Therefore, a tensile load does not act on the gas spring in the maximum length state, and therefore the gas spring is not easily damaged. As a result, even if the opening angle of the engine hood of the construction machine is sufficiently increased, the engine hood can be reliably held.

  In the opening and closing structure of the engine hood according to the second invention, in the first invention, the engine hood can be opened until the center of gravity of the engine hood is located on the opening side from the rotation center of the engine hood. Further, when the position of the center of gravity of the engine hood is located on the opening side from the rotation center of the engine hood, the gas spring has the maximum length.

  In this structure, even when the center of gravity of the engine hood is inclined to the opening side from the rotation center of the engine hood and the engine hood tries to open further by its own weight, no tensile load acts on the gas spring in the maximum length state. Furthermore, when the engine hood is closed, the reaction force of the gas spring does not act until the center of gravity of the engine hood is positioned closer to the closing side than the rotation center of the engine hood, so that the operation force can be reduced.

  In the opening and closing structure of the engine hood according to the third invention, in the first or second invention, the maximum opening angle extending mechanism is configured such that when the engine hood is opened, the urging force of the gas spring is extended until the gas spring extends to the maximum length. And a support portion that allows the gas spring to leave when the engine hood is further opened from the state where the gas spring is extended to the maximum length.

  In this structure, when the engine hood is opened, the support portion of the maximum angle expansion mechanism receives the biasing force of the gas spring. And this structure permits a gas spring to leave | separate from a support part, when opening an engine hood further from the state which extended the gas spring to the maximum length.

  In the engine hood opening and closing structure according to the fourth invention, in the first or second invention, the maximum opening angle extending mechanism has a link mechanism for connecting the gas spring to the engine room.

  In this structure, the link mechanism allows the engine hood to be further opened from the state where the gas spring extends to the maximum length.

  In the engine hood opening and closing structure according to the fifth invention, in the fourth invention, the link mechanism is rotatably connected to the engine room and a first end portion rotatably connected to one end of the gas spring. A link member having a second end portion and a support portion fixed to the engine room and receiving a biasing force of the gas spring through the link member until the engine hood opens at a predetermined angle.

  In this structure, when the engine hood is opened, the support portion of the link mechanism receives the urging force of the gas spring via the link member. Then, when the engine hood is further opened from the state in which the gas spring is extended to the maximum length, the link member rotates around the second end. That is, the gas spring follows the engine hood without receiving a pulling force with the maximum length.

  In the opening / closing structure of the engine hood according to the sixth aspect of the present invention, in the first or second aspect, the maximum opening angle expanding mechanism has a guide rail that supports the gas spring in the engine room.

  In this structure, the guide rail allows the engine hood to be further opened from the state where the gas spring is extended to the maximum length.

  In the opening and closing structure of the engine hood according to the seventh invention, in the sixth invention, the guide rail includes a support portion that receives a biasing force of the gas spring until the engine hood is opened, and a guide that extends from the support portion to the opening side of the engine hood. Part.

  In this structure, when the engine hood is opened, the support portion receives the biasing force of the gas spring. Then, when the engine hood is further opened from the state where the gas spring is extended to the maximum length, the gas spring is separated from the support portion. That is, the gas spring follows the engine hood without receiving a tensile force with the maximum length.

  In the engine hood opening and closing structure according to the eighth invention, in any one of the first to seventh inventions, the maximum opening angle of the engine hood is limited, and the engine hood is closed by a random force from a state where the engine hood is opened by a predetermined angle. It further includes a stay mechanism that restricts this.

  In this structure, the stay hood prevents the engine hood from opening further in a state where it is opened at a predetermined angle. Further, the stay mechanism prevents the engine hood from being closed by a random force from a state where the engine hood is opened at a predetermined angle.

  In the engine hood opening and closing structure according to the ninth invention, in the eighth invention, the stay mechanism has a stay having one end rotatably connected to the engine room and the other end connected to the engine hood. A protrusion is formed on the other end of the stay. The engine hood has a guide rail on which the protrusion is guided.

  In this structure, when the engine hood is opened, the stay rotates with respect to the engine room while the stay protrusion is guided by the guide rail of the engine hood.

  In the engine hood opening and closing structure according to the tenth invention, in the ninth invention, the guide rail receives a reaction force from the protrusion so that the engine hood does not open any more when the engine hood is opened at a predetermined angle; and And a second support portion that receives a reaction force from the protrusion so that the engine hood does not close when a random force is applied in a closing direction from a state where the engine hood is opened at a predetermined angle.

  In this structure, with the engine hood opened at a predetermined angle, the stay projections apply a reaction force to the first support portion of the guide rail, thereby supporting the engine hood so that it cannot be opened any further. Yes. Further, in a state where the engine hood is opened at a predetermined angle, the stay projection applies a reaction force to the second support portion of the guide rail, thereby supporting the engine hood so as not to be closed. As described above, the engine hood is maintained in an open state unless a special operation is performed by a human hand while the engine hood is open at a predetermined angle.

  In the engine hood opening and closing structure according to the eleventh aspect of the invention, in the tenth aspect of the invention, the guide rail has a linearly extending guide portion. The first support part and the second support part are provided at one end of the guide part.

  In this structure, the stay protrusion moves in the guide portion of the guide rail when the engine hood is opened, and is positioned in the vicinity of the first support portion and the second support portion when the engine hood is opened at a predetermined angle. Furthermore, the protrusion of the stay moves away from the vicinity of the first support portion and the second support portion of the guide rail when the engine hood is closed.

  According to the engine hood opening and closing structure according to the present invention, the engine hood can be reliably held even if the opening angle of the engine hood of the construction machine is sufficiently large.

  A hydraulic excavator 1 equipped with an engine hood opening and closing structure according to an embodiment of the present invention will be described below with reference to FIGS.

1. Overall Configuration of Hydraulic Excavator 1 As shown in FIG. 1, a hydraulic excavator 1 according to the present embodiment includes a lower traveling body 2, a swivel base 3, a work implement 4, a counterweight 5, an engine room 6, and equipment. A chamber 9, a cab 10, an opening / closing structure 21 for the engine hood 20, and a main frame (not shown) are provided.

  The lower traveling body 2 has the crawler belt P wound around the left and right ends of the traveling direction rotated to move the excavator 1 forward and backward, and the swivel base 3 is mounted on the upper surface side in a swingable state. .

  The swivel base 3 can be swung in any direction on the lower traveling body 2 and has a work machine 4, a counterweight 5, an engine room 6, and a cab 10 mounted on the upper surface.

  The work machine 4 is configured to include a boom 11, an arm 12 attached to the tip of the boom 11, and a bucket 13 attached to the tip of the arm 12. The work machine 4 is a civil engine that excavates earth and sand and gravel while moving the boom 11, arm 12, bucket 13, and the like up and down by hydraulic cylinders 11 a, 12 a, and 13 a included in a hydraulic circuit (not shown). Work at the construction site.

  The counterweight 5 is made of, for example, scrap iron or concrete in a box formed by assembling steel plates and is hardened. The counterweight 5 is an engine room 6 on the swivel 3 for balancing the vehicle body during mining. It is provided behind.

  The engine room 6 is disposed at the rear end of the swivel base 3 on a main frame (not shown) so as to be adjacent to the counterweight 5. In addition, the engine room 6 has an outer frame portion formed by an exterior frame, and forms a storage space for the engine and the like inside. The engine room 6 stores an engine, an aftercooler, and the like, which are power sources for driving the lower traveling body 2 and the work machine 4, in an internal storage space.

  Further, as shown in FIGS. 2 and 3, the engine room 6 has an opening for maintenance on the upper surface, and this opening is opened by an engine hood 20 that can be opened and closed via a hinge 22 except during maintenance. Covered.

  The equipment room 9 is disposed behind the work machine 4 and houses a fuel tank, a hydraulic oil tank, an operation valve, and the like (not shown).

  The cab 10 is a driver's cab in which an operator of the excavator 1 gets on and off, and is disposed on the left front side on the swivel 3 so that the tip of the work machine 4 can be seen. .

2. Engine Hood Open / Close Structure As shown in FIG. 2, the engine hood 20 open / close structure 21 is an open / close structure of the engine hood 20 mounted on the engine room 6 so as to cover a part of the upper surface of the engine room 6. .

  As shown in FIG. 2, the engine hood 20 is a substantially box-shaped lid member that is opened and closed during maintenance in the engine room 6. The engine hood 20 has a hinge 22 attached to the counterweight 5 side as a rotation center. Opened and closed in the front-rear direction.

  A pair of lock portions 23 are attached to the surface of the engine hood 20 on the side of the cab 10 so that the engine hood 20 does not shift to the open state when the engine hood 20 is closed. To fix.

  The handle 24 is disposed between the pair of lock portions 23 in the engine hood 20 and is used as a handle when the engine hood 20 is opened and closed.

  As shown in FIGS. 3 and 4, the opening / closing structure 21 of the engine hood 20 mainly includes an engine hood 20, a gas spring support mechanism 32, and a stay support mechanism 41.

(1) Gas Spring Support Mechanism The gas spring support mechanism 32 is composed of a pair of structures provided on both sides of the engine hood 20. In the following description, only the structure on one side will be described and replaced with the description on the structure on both sides.

  In FIG. 5, the left side of the drawing is the front side of the excavator 1 and the closing side of the engine hood 20. Further, the right side of the figure is the rear side of the excavator 1 and the open side of the engine hood 20. In FIG. 5, the closed position of the engine hood 20 is indicated by a broken line, and the open position is indicated by a solid line.

  The gas spring support mechanism 32 is a device that assists the operating force during the opening operation with the compressed gas in the gas spring. As shown in FIG. 5, the gas spring support mechanism 32 is disposed in the vicinity of the hinge 22 below the engine hood 20 with the engine hood 20 closed. The gas spring support mechanism 32 includes a gas spring 33, a link mechanism 34, and a support plate 35. The gas spring 33 and the link mechanism 34 are disposed closer to the engine hood than the hinge 22.

  The gas spring 33 has a general structure, and includes a tube 33a and a rod 33b that can be expanded and contracted therefrom. As shown in FIG. 5, the end of the tube 33 a of the gas spring 33 is rotatably connected to the engine hood 20. The end of the rod 33 b of the gas spring 33 is connected to the link mechanism 34. The link mechanism 34 has a link plate 34a. The first end of the link plate 34a is rotatably connected to the end of the rod 33b by a pin. The second end of the link plate 34a is rotatably connected to the exterior frame of the engine room 6 by a pin. Thereby, the link plate 34a can be rotated around the second end. The support plate 35 is a member fixed to the exterior frame of the engine room 6.

  In a state where the engine hood 20 is in the closed posture, the gas spring 33 is positioned such that the end of the rod 33b is below the end of the tube 33a and on the hinge 22 side. The first end of the link plate 34a is located below the second end and on the side opposite to the hinge 22 side. In this state, the surface of the link plate 34 a opposite to the gas spring 33 is in contact with the support plate 35. With the above arrangement, the reaction force of the gas spring 33 acts on the engine hood 20 and further acts on the support plate 35 via the link plate 34a.

  When opening the engine hood 20, for example, as shown in FIGS. 3 and 4, the operator 31 gets on the upper part of the engine room 6 and opens the engine hood 20. At this time, the operating force for opening the engine hood 20 is assisted by the reaction force of the gas spring 33.

  When the engine hood 20 is opened to the position shown by the solid line in FIG. 5 (about 65 degrees), the gas spring 33 extends to the maximum length, and extends in the vertical direction in the figure. At this time, the center of gravity 37 of the engine hood 20 is located closer to the engine hood closing side (left side in FIG. 5) than the hinge 22 that is the rotation center of the engine hood 20. When the engine hood 20 is further tilted to the opening side from this state, the gas spring 33 follows the movement of the engine hood 20 in a state where the gas spring 33 extends to the maximum length. As shown in FIG. 6, the link plate 34a rotates around the first end, and the second end follows the rod 33b. As described above, when the opening angle of the engine hood 20 becomes equal to or larger than the predetermined angle and the gas spring 33 reaches the maximum length, no pulling force acts on the gas spring 33 thereafter. Therefore, the gas spring 33 is not easily damaged. In the state shown in FIG. 6, the engine hood 20 is open so as to extend in the vertical direction, and the center of gravity 37 of the engine hood 20 is on the opening side of the engine hood 20 (see FIG. 6 on the right). In this case, the engine hood 20 tends to tilt further to its open side by its own weight, but even in that case, no tensile force acts on the gas spring 33. From the above, the gas spring 33 is hardly damaged.

  When the engine hood 20 is closed, a reaction force from the gas spring 33 does not act up to a predetermined angle (for example, about 65 degrees), so that a large force is not required for closing. Then, when the center of gravity 37 of the engine hood 20 moves to the closing side from the hinge 22 that is the center of rotation, the resistance due to the reaction force of the gas spring 33 is reduced by the self-weight of the engine hood 20 thereafter.

(2) Stay support mechanism The stay support mechanism 41 is a mechanism for restricting the maximum opening angle of the engine hood 20 and restricting the engine hood 20 from being closed by a random force from a state where the engine hood 20 is opened by a predetermined angle. As shown in FIG. 4, the stay support mechanism 41 is disposed at an intermediate position in the width direction of the engine hood 20 (slightly right from the center in the figure).

  In FIG. 7, the left side of the drawing is the front side of the excavator 1 and the closing side of the engine hood 20. Further, the right side of the figure is the rear side of the excavator 1 and the open side of the engine hood 20. In FIG. 7, the closed position of the engine hood 20 is indicated by a broken line, and the open position is indicated by a solid line.

  The stay support mechanism 41 mainly includes a stay main body 42 and a guide rail 44. The stay main body 42 is an elongated rod-like member. A protrusion 43 at the lower end of the stay main body 42 is rotatably supported by a part of the engine room. A protrusion 42a at the upper end of the stay main body 42 has a cylindrical shape and engages with a guide rail 44 (described later).

  The guide rail 44 is a plate-like member attached to the back side surface of the engine hood 20. The guide rail 44 has a slit-shaped guide portion 45 that extends in the front-rear direction of the engine hood 20 (left-right direction in FIG. 7). The guide portion 45 includes a straight portion 46 extending in the front-rear direction of the engine hood 20 and a support portion 47 formed at one end thereof (the right end in FIG. 7) in the state indicated by the broken line in FIG. The support portion 47 is a substantially circular portion wider than the straight portion 46. More specifically, in the state shown by the broken line in FIG. 7, the left end of FIG. 7 (the front end of the excavator 1) of the linear portion 46 is positioned below the right end of FIG. 7 (the rear end of the excavator 1). Further, the support portion 47 is located slightly above the straight portion 46. That is, the support portion 47 does not have a portion protruding downward in the state of FIG. 7 with respect to the straight portion 46, and protrudes only upward.

  In the closed posture of the engine hood 20 indicated by the broken line on the left side of FIG. 7, the protrusion 42 a of the stay main body 42 is located at one end of the straight portion 46 of the guide portion 45 (the end opposite to the support portion 47 side). When the engine hood 20 is opened, the engine hood 20 rotates about the hinge 22. At this time, the protrusion 42 a of the stay main body 42 moves the linear portion 46 of the guide portion 45 toward the support portion 47. In addition, what is shown by the alternate long and short dash line in FIG. 7 is the track of the protrusion 42 a of the stay main body 42.

  In the open posture of the engine hood 20 indicated by the solid line on the right side of FIG. 7, the engine hood 20 extends substantially in the vertical direction. At this time, the protrusion 42 a of the stay main body 42 has moved to the support portion 47 of the guide portion 45. Therefore, the engine hood 20 is immovable by the stay main body 42 neither on the opening side nor on the closing side (described later). In this state, the center of gravity 37 of the engine hood 20 is located on the opening side (right side in FIG. 7) of the engine hood 20 from the hinge 22 of the engine hood 20. For this reason, engine hood 20 is going to open further with dead weight.

  FIG. 8 shows a support relationship when the engine hood 20 is going to be further opened by its own weight. In addition, the dashed-dotted line Q shown in the figure is the track | orbit of the protrusion 42a of the stay main body 42, and the protrusion 42a cannot take positions other than this track | orbit. In FIG. 8, the support portion 47 is continuous while smoothly curving from the straight portion 46 to the right side. In particular, the left side wall of the guide portion 45 in FIG. 8 is a portion where the protrusion 42 a of the stay body 42 slides when the engine hood is opened, and is smoothly continuous from the straight portion 46 to the support portion 47. On the other hand, the boundary between the straight portion 46 and the support portion 47 on the right side wall of the guide portion 45 in FIG. This is because the support portion 47 has a substantially circular shape and is shifted from the traveling direction of the straight portion 46 to the right side in FIG.

  In FIG. 8, the protrusion 42 a of the stay main body 42 is in contact with the first support portion 47 a of the support portion 47. The first support portion 47a of the support portion 47 is a lower portion in FIG. 8 (a portion continuing from the left side wall of the straight portion 46 in FIG. 8). In this state, the engine hood 20 is about to rotate further about the hinge 22, and the first support portion 47a applies a load to the protrusion 42a of the stay main body 42 (the broken line M in FIG. This is the rotation trajectory of the hood 20, and the first support portion 47a applies a force to the protrusion 42a along that. As a result, the protrusion 42 a of the stay main body 42 applies a reaction force to the first support portion 47 a of the support portion 47. In this state, since the structure of the support portion 47 blocks the track of the protrusion 42a of the stay main body 42, the engine hood 20 cannot be further opened from the state of FIG.

  Next, the support relationship when the engine hood 20 is about to be closed by a random external force from the state of FIG. 8 will be described. When the engine hood 20 rotates to the side close to the hinge 22, the engine hood 20 is rotated by the stay main body 42 as shown in FIG. 9 when the engine hood 20 and the stay main body 42 are slightly rotated. Stop (described later). That is, the engine hood 20 is not closed by a random external force.

  Specifically, as shown in FIG. 9, the second support portion 47 b of the support portion 47 is supported by the protrusion 42 a of the stay main body 42. In this state, the second support portion 47b applies a load to the protrusion 42a along the rotation direction of the engine hood 20 (the broken line M in FIG. 9 is the rotation track of the engine hood 20, and the second support portion 47b applies a force to the protrusion 42a along with it.) As a result, the protrusion 42 a of the stay main body 42 applies a reaction force to the second support portion 47 b of the support portion 47. In this state, the structure of the support portion 47 blocks the track of the protrusion 42a of the stay main body 42, so the engine hood 20 cannot be further closed from the state of FIG.

  In order to close the engine hood 20 from the state of FIG. 8, the operator 31 needs to operate both the stay main body 42 and the engine hood 20. Specifically, from the state of FIG. 8, the stay main body 42 is rotated to the engine hood closing side to move the protrusion 42a from the support portion 47 to the linear portion 46 side, and at the same time, the engine hood 20 is tilted to the closing side. . Thereby, the protrusion 42 a of the stay main body 42 moves from the support portion 47 to the linear portion 46.

3. Summary of opening and closing operation of front cover (1) Operation of opening engine hood 20 When opening the engine hood 20, the operator 31 lifts the tip of the engine hood 20. The operating force for opening the engine hood 20 is assisted by the reaction force of the gas spring 33 of the gas spring support mechanism 32 up to the first predetermined angle.

  When the engine hood 20 reaches the first predetermined angle or more, the engine hood 20 opens in a state where no tensile force acts on the gas spring 33. In particular, since the engine hood 20 is inclined to the opening side by its own weight beyond a certain angle, the operating force for the opening operation of the engine hood 20 can be small.

  When the engine hood 20 reaches the second predetermined angle, the protrusion 42 a of the stay main body 42 of the stay support mechanism 41 fits into the support portion 47 of the guide portion 45 of the guide rail 44. Thereby, the engine hood 20 does not open any more. Further, even if a random external force acts in the closing direction on the engine hood 20 in this state, the engine hood 20 is not closed by the engagement between the protrusion 42 a and the support portion 47.

(2) Operation for Closing Engine Hood 20 When closing the engine hood 20, the operator 31 pulls the stay main body 42 forward and tilts the engine hood 20 forward. Thereby, the engagement between the protrusion 42a and the support portion 47 is released, and the engine hood 20 can be turned to the closing side.

  Until the engine hood 20 reaches the first predetermined angle, the engine hood 20 does not receive a reaction force from the gas spring 33 of the gas spring support mechanism 32. Therefore, the operator 31 can rotate the engine hood 20 with a small force. Further, when the second predetermined angle is reached, the reaction force from the gas spring 33 acts on the engine hood 20 thereafter, but the engine hood 20 is inclined to the closed side by its own weight below this angle. The operating force for the closing operation is small.

4). Features of the Invention (1) The engine hood opening / closing structure 21 is an opening / closing structure of the engine hood 20 that covers the upper part of the engine room of the excavator 1, and includes an engine hood 20, a gas spring 33, and a maximum angle expansion mechanism ( 34, 35). The engine hood 20 is rotatably supported in the engine room 6 of the excavator 1. The gas spring 33 applies a biasing force to the engine hood 20 when the engine hood 20 is opened. The maximum opening angle expansion mechanism (34, 35) allows the engine hood 20 to be further opened from the state in which the gas spring 33 is extended to the maximum length.

  In this structure, when the engine hood 20 is opened, the gas spring 33 assists the operating force. As the opening angle of the engine hood 20 increases, the gas spring 33 extends. When the engine hood 20 is further opened from the state in which the gas spring 33 is extended to the maximum length, the engine hood 20 is further opened by the maximum opening angle expansion mechanism (34, 35). Therefore, a tensile load does not act on the gas spring 33 in the maximum length state. From the above, the gas spring 33 is not easily damaged. As a result, even if the opening angle of the engine hood 20 of the excavator 1 is sufficiently large, the engine hood 20 can be reliably held.

  (2) The engine hood 20 can be opened to a state where the center of gravity 37 of the engine hood 20 is located on the opening side with respect to the rotation center (22) of the engine hood 20. Moreover, when the gravity center position of the engine hood 20 is located on the opening side with respect to the rotation center (22) of the engine hood, the gas spring 33 has the maximum length.

  In this structure, even if the center of gravity 37 of the engine hood 20 is inclined to the opening side from the rotation center of the engine hood 20 and the engine hood 20 tries to open further by its own weight, no tensile load acts on the gas spring 33 in the maximum length state.

  (3) When the engine hood 20 is opened, the maximum opening angle expansion mechanism (34, 35) receives the urging force of the gas spring 33 until the gas spring 33 extends to the maximum length, and the gas spring 33 extends to the maximum length. And a support plate 35 that allows the gas spring 33 to be separated when the engine hood 20 is opened.

  In this structure, when the engine hood 20 is opened, the support plate 35 of the maximum opening angle expansion mechanism (34, 35) receives the urging force of the gas spring 33. The support plate 35 allows the gas spring 33 to move away from the support plate 35 when the engine hood 20 is further opened from the state in which the gas spring 33 extends to the maximum length.

  (4) The maximum opening angle expansion mechanism (34, 35) has a link mechanism 34 that connects the gas spring 33 to the engine room 6.

  In this structure, the link mechanism 34 allows the engine hood 20 to be further opened from the state in which the gas spring 33 extends to the maximum length.

  (5) The link mechanism 34 includes a link plate 34a having a first end pivotally connected to one end of the gas spring 33 and a second end pivotally connected to the engine room 6, and an engine room. 6 and a support plate 35 that receives the urging force of the gas spring 33 through the link plate 34a until the engine hood 20 opens at a predetermined angle.

  In this structure, when the engine hood 20 is opened, the support plate 35 of the link mechanism 34 receives the urging force of the gas spring 33 via the link plate 34a. Then, when the engine hood 20 is further opened from the state in which the gas spring 33 is extended to the maximum length, the link plate 34a rotates around the second end portion. That is, the gas spring 33 follows the engine hood 20 without receiving a tensile force with the maximum length.

  (6) The engine hood opening / closing structure 21 further includes a stay support mechanism 41 that limits the maximum opening angle of the engine hood 20 and restricts the engine hood 20 from being closed by a random force from a state where the engine hood 20 is opened by a predetermined angle. Yes.

  In this structure, the stay support mechanism 41 prevents the engine hood 20 from being opened further in a state where the engine hood 20 is opened at a predetermined angle. Further, the stay support mechanism 41 prevents the engine hood 20 from being closed by a random force from a state where the engine hood 20 is opened by a predetermined angle.

  (7) The stay support mechanism 41 includes a stay main body 42 having one end rotatably connected to the engine room 6 and the other end connected to the engine hood 20. A protrusion 42 a is formed on the other end of the stay main body 42. The engine hood 20 has a guide portion 45 through which the protrusion 42a is guided.

  In this structure, when the engine hood 20 is opened, the stay main body 42 rotates with respect to the engine room 6 of the excavator 1 while the protrusion 42 a of the stay main body 42 is guided by the guide portion 45 of the engine hood 20.

  (8) The guide portion 45 is a first support portion 47a that receives a reaction force from the protrusion 42a so that the engine hood 20 is not opened further when the engine hood 20 is opened at a predetermined angle, and a direction in which the engine hood 20 is closed from a state where the engine hood 20 is opened at a predetermined angle. And a second support portion 47b that receives a reaction force from the protrusion 42b so as not to be closed when a random force is applied.

  In this structure, with the engine hood 20 opened at a predetermined angle, the protrusion 42a of the stay main body 42 applies a reaction force to the first support portion 47a of the guide portion 45. Supports not to open. In addition, in a state where the engine hood 20 is opened at a predetermined angle, the protrusion 42a of the stay main body 42 applies a reaction force to the second support portion 47b of the guide portion 45 so that the engine hood 20 is not closed. I support it. As described above, the engine hood 20 is maintained in a state where the engine hood 20 is opened at a predetermined angle unless a special operation is performed by a human hand.

  (9) The guide part 45 has a linear part 46 extending linearly. The first support portion 47 a and the second support portion 47 b are provided at one end of the linear portion 46.

  In this structure, the protrusion 42a of the stay main body 42 moves along the straight portion 46 of the guide portion 45 when the engine hood 20 is opened, and the first support portion 47a and the second support portion 47a when the engine hood 20 is opened at a predetermined angle. Located in the vicinity of the support portion 47b. Further, when the engine hood 20 is closed, the protrusion 42a of the stay main body 42 moves away from the vicinity of the first support portion 47a and the second support portion 47b of the guide portion 45 and moves on the linear portion 46.

  (10) The hydraulic excavator 1 is often used at a construction site as a construction machine. Therefore, sometimes it is necessary to move the engine hood 20 in an open state. In this case, since the engine hood 20 is securely held by the stay support mechanism 41 on both the open side and the closed side, the engine hood 20 does not rotate suddenly. That is, it is difficult for the engine hood 20 to suddenly close or the gas spring 33 to be damaged.

  Further, when the excavator 1 is used on an inclined ground, it can be used even when the engine hood 20 is opened as described above. In that case, it is conceivable that the positional relationship between the center of gravity and the rotation center of the engine hood 20 set on the basis of a flat ground is reversed. However, since the engine hood 20 is securely held by the stay support mechanism 41 on both the opening side and the closing side, the engine hood 20 does not rotate suddenly. That is, it is difficult for the engine hood 20 to suddenly close or the gas spring 33 to be damaged.

3. Second Embodiment FIGS. 10 and 11 show another embodiment of a gas spring support mechanism according to the present invention.
The gas spring support mechanism 61 is a device that assists the operating force during the opening operation with the compressed gas in the gas spring.

  As shown in FIG. 10, the gas spring support mechanism 61 is disposed below the engine hood 20 with the engine hood 20 closed. The gas spring support mechanism 61 includes a gas spring 62 and a guide rail 63.

  The gas spring 62 has a general structure, and includes a tube 62a and a rod 62b that can be expanded and contracted therefrom. As shown in FIG. 10, the end of the tube 62 a of the gas spring 62 is rotatably connected to the engine hood 20. The end of the rod 62b of the gas spring 62 is supported by the guide rail 63 (described later).

  The guide rail 63 is a member for supporting the gas spring 62 in the engine room 6 and allows the engine hood 20 to be further opened from the state in which the gas spring 62 extends to the maximum length.

  The guide rail 63 is a member provided at the upper part of the exterior frame of the engine room 6 and is a plate member that extends long in the left-right direction (front-rear direction of the hydraulic excavator 1) in FIG. A guide portion 64 extending in the left-right direction in FIG. 10 is formed on the guide rail 63. The guide portion 64 is a slit, and a protrusion 62 c provided at the end of the rod 62 b of the gas spring 62 is engaged with the guide portion 64. The left end of the guide portion 64 in FIG. 10 is a support portion that receives the reaction force of the gas spring 62 until the gas hood 62 reaches its maximum length by opening the engine hood 20.

  Next, the operation when opening the engine hood 20 will be described. When the engine hood 20 is opened, the left end in FIG. 10 of the guide portion 64 receives the urging force of the gas spring 62. When the engine hood 20 is opened to the position shown on the right side of FIG. 10, the gas spring 62 extends to the maximum length. At this time, the center of gravity of the engine hood 20 is located on the closing side (left side in FIG. 10) of the engine hood 20 with respect to the hinge 22 that is the rotation center of the engine hood 20. When the engine hood 20 is further tilted to the open side from this state, the gas spring 62 follows the movement of the engine hood 20 in a state where the gas spring 62 extends to the maximum length. That is, the protrusion 62c of the rod 62b of the gas spring 62 moves to the right side in the guide portion 64 of the guide rail 63. As described above, when the opening angle of the engine hood 20 becomes equal to or larger than the predetermined angle and the gas spring 62 reaches the maximum length, no pulling force acts on the gas spring 62 thereafter. Therefore, the gas spring 62 is not easily damaged.

4). Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

  (A) In the above embodiment, a hydraulic excavator has been described as an example of a construction machine to which the engine hood opening and closing structure of the present invention is applied. However, the present invention is not limited to this. For example, the present invention can be similarly applied to an engine room of a wheel loader.

  (B) In the embodiment, both the gas spring support mechanism and the stay support mechanism are applied to one construction machine, but only one of them may be provided.

  The opening and closing structure of the engine hood of the present invention has an effect that the engine hood can be securely held even if the opening angle of the engine hood of the construction machine is sufficiently large. It can be widely applied to various construction machines equipped.

The perspective view which shows the structure of the external appearance of the hydraulic shovel which employ | adopted the opening / closing structure of the engine hood which concerns on one Embodiment of this invention. FIG. 2 is a perspective view showing a configuration around an engine room and a counterweight including an opening / closing structure of an engine hood mounted on the rear side of the hydraulic excavator in FIG. 1. The side view which shows the open state of an engine hood. The figure seen from the left side of FIG. 4 which shows the open state of an engine hood. The side view which shows the relationship between a gas spring and a link mechanism in the state which closed the engine hood and opened about 65 degree | times. The side view which shows the relationship between a gas spring and a link mechanism in the state which opened the engine hood about 90 degree | times. The side view which shows the change of the attitude | position of a stay support mechanism in an engine hood closed state and the state opened about 90 degree | times. The side view which shows the relationship between a stay support mechanism and a guide rail when the force which tries to open an engine hood acts on an engine hood in the state which the engine hood opened about 90 degree | times. The side view which shows the relationship between a stay mechanism and a guide rail when the force which tries to close an engine hood acts on an engine hood in the state which the engine hood opened about 90 degree | times. In 2nd Embodiment, the side view which shows the relationship between a gas spring and a guide rail in the state which the engine hood opened about 60 degree | times. The side view which shows the relationship between a gas spring and a guide rail in the state which the engine hood opened about 90 degree | times in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Lower traveling body 3 Swivel base 4 Working machine 5 Counterweight 6 Engine room 9 Equipment room 20 Engine hood 21 Engine hood opening / closing structure 22 Hinge 23 Lock part 24 Handle 32 Gas spring support mechanism 33 Gas spring 33a Tube 33b Rod 34 link mechanism 34a link plate 35 support plate 41 stay support mechanism 42 stay main body 42a protrusion 44 guide rail 45 guide part 46 linear part 47 support part 47a first support part 47b second support part 61 gas spring support mechanism 62 gas spring 62a tube 62b Rod 63 Guide rail 64 Guide part

Claims (11)

An opening and closing structure of an engine hood that covers an upper part of an engine room of a construction machine,
An engine hood rotatably supported in the engine room;
A gas spring that applies a biasing force to the engine hood when the engine hood is opened;
A maximum opening angle expansion mechanism that allows the engine hood to open from a state where the gas spring extends to a maximum length;
Engine hood opening and closing structure equipped with. The engine hood can be opened until the position of the center of gravity of the engine hood is located on the opening side of the rotation center of the engine hood,
2. The engine hood opening and closing structure according to claim 1, wherein the gas spring has a maximum length when a position of a center of gravity of the engine hood is located on an opening side with respect to a rotation center of the engine hood.   The maximum opening angle extending mechanism receives the biasing force of the gas spring until the gas spring extends to a maximum length when the engine hood is opened, and the engine hood is further opened from a state where the gas spring is extended to the maximum length. The opening / closing structure of the engine hood according to claim 1, further comprising a support portion that allows the gas spring to be sometimes separated.   The engine hood opening and closing structure according to claim 1, wherein the maximum opening angle extending mechanism includes a link mechanism that connects the gas spring to the engine room.   The link mechanism is fixed to the engine room, a link member having a first end pivotally connected to one end of the gas spring and a second end pivotally connected to the engine room. The opening / closing structure of the engine hood according to claim 4, further comprising: a support portion that receives an urging force of the gas spring through the link member until the engine hood opens at a predetermined angle.   The engine hood opening and closing structure according to claim 1, wherein the maximum opening angle extending mechanism includes a guide rail that supports the gas spring in the engine room.   The engine hood according to claim 6, wherein the guide rail includes a support portion that receives an urging force of the gas spring until the engine hood is opened, and a guide portion that extends from the support portion toward the opening side of the engine hood. Opening and closing structure.   8. The stay mechanism according to claim 1, further comprising a stay mechanism that limits a maximum opening angle of the engine hood and restricts the engine hood from being closed by a random force from a state where the engine hood is opened at a predetermined angle. Engine hood opening and closing structure. The stay mechanism has a stay having one end rotatably connected to the engine room and the other end connected to the engine hood.
A protrusion is formed on the other end of the stay,
The engine hood opening and closing structure according to claim 8, wherein the engine hood includes a guide rail through which the protrusion is guided.   The guide rail includes a first support portion that receives a reaction force from the protrusion so that the engine hood is not opened any more when the engine hood is opened at a predetermined angle, and a random force in a direction to close the engine hood when the engine hood is opened at a predetermined angle. The open / close structure for an engine hood according to claim 9, further comprising: a second support portion that receives a reaction force from the protrusion so as not to close when acted upon. The guide rail has a guide portion extending linearly,
The engine hood opening and closing structure according to claim 10, wherein the first support part and the second support part are provided at one end of the guide part.

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