Cylinder cover, hydraulic cylinder, and work machine

Abstract

Provided are a cylinder cover (25), a hydraulic cylinder (24), and a work machine (1) that can operate smoothly.　The cylinder cover (25) comprises: a cover body (33) of which a first edge side is attached to the tip-end side of a cylinder rod (32), and which moves together with the cylinder rod (32) as the hydraulic cylinder (24) extends and contracts; and a guide part (25E) that supports the cover body (33) slidably along the extending direction of the cylinder rod (32). The guide part (25E) comprises a guide plate (34) provided on the outer circumferential part of a cylinder tube (31) of the hydraulic cylinder (24) and extending in an outer circumferential tangential direction of a cross section perpendicular to the extending direction of the cylinder tube (31), and a pair of end parts (35) provided on opposite edge parts (41) of the guide plate (34) in the tangential direction. The cover body (33) has a first portion (37a) facing a first side surface (42) that is a surface of the end parts (35) opposite to the cylinder tube (31), a second portion (37b) facing an edge surface (45) of the end parts (35) in the tangential direction, and a third portion (37c) facing a second side surface (43) that is a surface of the end parts (35) adjacent to the cylinder tube (31). The end parts (35) have, at the edge surface (45), a first convex surface part (51) bent to be convex to the second portion (37b).

Description

Technical Field

[0001] The present invention relates to a cylinder cover, a hydraulic cylinder, and a working machine provided with the same.

Background Art

[0002] Conventionally, as a cylinder cover attached to a hydraulic cylinder of a working machine such as a backhoe, a cover member disclosed in Patent Document 1 is known.

[0003] The cover member disclosed in Patent Document 1 includes a mounting plate fixed to a cylinder tube of a working tool cylinder, a pair of guide members respectively mounted so as to cover attachment portions projecting left and right from the mounting plate, a pair of slide members extending in the same direction as the extending direction of the cylinder tube, a support body supporting the slide members, and a mounting body connected to a piston rod of the working tool cylinder and holding the support body. The guide members provided at the left and right end portions of the mounting plate are respectively inserted into inner groove portions of the slide members, whereby the mounting plate is slidably connected to the mounting body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, with this type of cylinder cover, variations in assembly precision with respect to the hydraulic cylinder and distortion over time can cause a misalignment between the extension direction of the hydraulic cylinder and the extension direction of the sliding member (groove). In such cases, the end face of the guide member may come into contact with the inner surface of the groove of the sliding member, increasing sliding resistance and potentially leading to abnormal noise or malfunction during operation. On the other hand, increasing the gap between the guide member and the sliding member to avoid the above contact can lead to increased vibration of the cylinder cover. Furthermore, foreign matter may enter the inside of the sliding member through the gap, potentially causing malfunction.

[0006] The present invention was made to solve these problems, and aims to provide a cylinder cover, a hydraulic cylinder, and a work machine equipped therewith that can operate smoothly while suppressing the generation of abnormal noise and vibration. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention employs the following technical means.

[0008] A cylinder cover according to one aspect of the present invention is a cylinder cover mounted on a hydraulic cylinder to protect the cylinder rod of the hydraulic cylinder, comprising: a cover body whose first end is attached to the tip of the cylinder rod and moves together with the cylinder rod in accordance with the extension and contraction of the hydraulic cylinder; and a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, wherein the guide portion comprises: a guide plate provided on the outer circumference of the cylinder tube of the hydraulic cylinder extending in the tangential direction of the outer circumference of a cross section perpendicular to the extension direction of the cylinder tube; and a pair of end portions provided at both ends of the guide plate in the tangential direction, wherein the cover body has a first portion facing a first side surface which is the side of the end portion opposite to the cylinder tube; a second portion facing the end surface in the tangential direction of the end portion; and a third portion facing the second side surface which is the side of the end portion facing the cylinder tube, wherein the end portion has a first curved convex surface portion on the end surface which is curved to be convex toward the second portion. The first curved convex portions of each end provided on both sides in the tangential direction are formed in a concentric arc shape when viewed from the direction normal to the surface of the guide plate.It is.

[0010] A cylinder cover according to one aspect of the present invention is a cylinder cover mounted on a hydraulic cylinder to protect the cylinder rod of the hydraulic cylinder, comprising: a cover body whose first end is attached to the tip of the cylinder rod and moves together with the cylinder rod in accordance with the extension and contraction of the hydraulic cylinder; and a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, wherein the guide portion comprises: a guide plate provided on the outer circumference of the cylinder tube of the hydraulic cylinder extending in the tangential direction of the outer circumference of a cross section perpendicular to the extension direction of the cylinder tube; and a pair of end portions provided at both ends of the guide plate in the tangential direction, wherein the cover body has a first portion facing a first side surface which is the side of the end portion opposite to the cylinder tube; a second portion facing the end surface in the tangential direction of the end portion; and a third portion facing the second side surface which is the side of the end portion facing the cylinder tube, wherein the end portion has a first curved convex surface portion on the end surface which is curved to be convex toward the second portion. The first curved convex portion is, The shape of the guide plate as viewed from the direction normal to the plate surface is, The second portions provided on both sides of the cover body in the tangential direction are formed in an arc shape that forms part of a circle with a diameter smaller than the distance between them. ru .

[0011] The first curved convex portions of each end provided on both sides in the tangential direction may be formed in a concentric arc shape.

[0012] The end face may have inclined surfaces on both sides of the first curved convex portion in the direction of extension of the cylinder rod, such that the further away from the first curved convex portion in the direction of extension of the cylinder rod the further away from the second portion the further away the second portion the further away it is from the first curved convex portion in the direction of extension of the cylinder rod.

[0013] The end face may have a curved shape such that the cross-sectional shape perpendicular to the extension direction of the cylinder rod is convex toward the second portion, or it may have a shape in which the corner opposite to the cylinder tube and the corner on the cylinder tube side of the cross-sectional shape perpendicular to the extension direction of the cylinder rod are chamfered.

[0014] The end portion may have a second curved convex surface portion on at least one of the first and second side surfaces, which is curved to be convex in the direction normal to the surface of the guide plate.

[0015] The second curved convex portion may have a cross-sectional shape perpendicular to the extension direction of the cylinder rod, which is formed in an arc shape.

[0016] The end portion may be formed of a resin material.

[0017] A hydraulic cylinder according to one aspect of the present invention is fitted with the cylinder cover.

[0018] The working machine according to one aspect of the present invention includes a machine body and a working device mounted on the machine body, and the working device includes the hydraulic cylinder.

[0019] A work machine according to one aspect of the present invention comprises a machine body and a work device attached to the machine body, The working device A hydraulic cylinder, a cylinder cover mounted on the hydraulic cylinder to protect the cylinder rod of the hydraulic cylinder, has a cylinder bracket that supports a first end portion on the tip side of the cylinder rod and, and The cylinder cover comprises a cover body whose first end is attached to the tip of the cylinder rod and moves together with the cylinder rod in accordance with the extension and retraction of the hydraulic cylinder, and a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, the guide portion comprising a guide plate provided on the outer circumference of the cylinder tube of the hydraulic cylinder extending in the tangential direction of the outer circumference of a cross section perpendicular to the extension direction of the cylinder tube, and a pair of end portions provided at both ends of the guide plate in the tangential direction, the cover body having a first portion facing a first side surface which is the side of the end portion opposite to the cylinder tube, a second portion facing the end surface in the tangential direction of the end portion, and a third portion facing the second side surface which is the side of the end portion facing the cylinder tube, the end portion having a first curved convex surface portion on the end surface which is curved to be convex toward the second portion, the cylinder bracket has a pair of bracket side plates that are erected at intervals in one direction and sandwich the first end portion, and a cover plate that covers a separation portion between the bracket side plates. The bracket side plate has a cutout portion, and the cover plate has a lid piece that covers the cutout portion. ru .

[0020] The lid piece may be formed by bending a part of the cover plate.

[0021] The first end side of the cylinder cover is attached to the tip side of the cylinder rod by a bolt from the first direction, and the cover plate may be provided at a position that does not overlap with the bolt mounting portion when viewed from the first direction.

[0022] The cutout portion may be a notch formed at the tip edge portion of the bracket side plate.

Effect of the Invention

[0024] According to the above cylinder cover, the gap between the end face of the end portion and the second portion of the cover body can be reduced, and the contact resistance between the end face and the second portion can also be reduced. Therefore, it is possible to suppress the generation of abnormal noise and vibration and to operate smoothly.

Brief Description of the Drawings

[0025] [Figure 1] It is a left front perspective view of the working machine. [Figure 2] It is a left side view of the working machine. [Figure 3] It is a top view of the swivel base. [Figure 4] This is a front perspective view of the work equipment. [Figure 5] This is a partially disassembled perspective view of the area around the hydraulic cylinder. [Figure 6] This is a downward cross-sectional view of the cylinder cover. [Figure 7] This is a front view cross-sectional view of the cylinder cover. [Figure 8] This is a partially disassembled perspective view of the area around the third cylinder bracket. [Figure 9] This is a perspective view of the area around the third cylinder bracket. [Figure 10] This is a downward cross-sectional view of a cylinder cover showing another embodiment. [Modes for carrying out the invention]

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0027] As shown in Figures 1 and 2, the implement 1 of this embodiment is a backhoe equipped with a turntable (machine body) 2, a traveling device 3, and a work device 4. A cabin 5 is mounted on the turntable 2. As shown in Figure 2, a driver's seat 6 is provided inside the cabin 5 where the operator sits. Note that the implement 1 is not limited to a backhoe and may be other types of implements.

[0028] Hereinafter, the direction the driver seated in the driver's seat 6 is facing (direction X1 as seen by the arrow in Figures 1 and 2, etc.) will be referred to as the front of the turntable 2, and the opposite direction (direction X2 as seen by the arrow in Figures 1 and 2, etc.) will be referred to as the rear of the turntable 2. Also, the left side of the driver (direction Y1 as seen by the arrow in Figures 1 and 3, etc.) will be referred to as the left side of the turntable 2, and the right side of the driver (direction Y2 as seen by the arrow in Figures 1 and 3, etc.) will be referred to as the right side of the turntable 2. Furthermore, the area above the driver (direction Z1 as seen by the arrow in Figures 1 and 2, etc.) will be referred to as the upper side of the turntable 2, and the area below the driver (direction Z2 as seen by the arrow in Figures 1 and 2, etc.) will be referred to as the lower side of the turntable 2.

[0029] <Aircraft> As shown in Figure 2, the turntable (machine body) 2 is supported on the upper part of the traveling device 3 via a slewing bearing 7 so that it can rotate left and right. In other words, the turntable 2 is supported so that it can rotate around the slewing axis (axis extending in the vertical direction) L1 relative to the traveling device 3. The slewing axis L1 is the rotation center of the slewing bearing 7.

[0030] As shown in Figure 3, a prime mover U1 is mounted inside the rear of the turntable 2. The prime mover U1 is a diesel engine. The prime mover U1 may also be a gasoline engine, an electric motor, or a hybrid of an engine and an electric motor. A hydraulic pump U2 is connected to the prime mover U1. The hydraulic pump U2 is driven by the power of the prime mover U1 and supplies hydraulic fluid (pressurized oil) to hydraulic actuators such as the hydraulic motor and hydraulic cylinder 24 equipped on the work machine 1, which will be described later.

[0031] <Traction device> As shown in Figures 1 and 2, the running device 3 has a running frame 3A and a running mechanism 3B. The running frame (track frame) 3A is a structure to which the running mechanism 3B is attached and which supports the turntable 2 from below. The running mechanism 3B is, for example, a crawler type. A dozer device 14 is attached to the front of the running device 3. Note that the running device 3 is not limited to a crawler type, but may also be a wheeled type.

[0032] <Working equipment> The working device 4 is located on the front side of the turntable 2 and is driven by hydraulic fluid discharged from the hydraulic pump U2. The working device 4 is connected to a support bracket 2A located on the front of the turntable 2 via a swing bracket 2B. The swing bracket 2B is pivotally supported on the front of the support bracket 2A so as to be able to swing around a vertical axis (an axis extending in the vertical direction).

[0033] The work device 4 includes a boom 21, an arm 22, and a bucket (working tool) 23. The base end of the boom 21 is pivotally supported on the swing bracket 2B so as to be able to swing around a horizontal axis (an axis extending in the left-right direction). In other words, the boom 21 is pivotally connected to the swing bracket 2B so as to be able to swing up and down. The base end of the arm 22 is pivotally supported on the tip of the boom 21 so as to be able to swing around a horizontal axis (an axis extending in the left-right direction). In other words, the arm 22 is pivotally connected to the boom 21 so as to be able to swing in the front-rear and up-down directions. The base end of the bucket 23 is pivotally supported on the tip of the arm 22 so as to be able to swing around a horizontal axis (an axis extending in the left-right direction). In other words, the bucket 23 is pivotally connected to the arm 22 so as to be able to perform scooping and dumping operations. The work machine 1 can be fitted with other working tools (hydraulic attachments) that can be driven by hydraulic fluid in place of or in addition to the bucket 23. Other tools include hydraulic breakers, hydraulic crushers, angle brooms, earth augers, pallet forks, sweepers, mowers, and snow blowers.

[0034] The work device 4 is driven by a hydraulic cylinder 24. The hydraulic cylinder 24 includes a swing cylinder C1, a boom cylinder C2, an arm cylinder C3, and a bucket cylinder (work tool cylinder) C4. The swing bracket 2B is swingable by the extension and retraction of the swing cylinder C1. The boom 21 is swingable by the extension and retraction of the boom cylinder C2. The arm 22 is swingable by the extension and retraction of the arm cylinder C3. The bucket 23 is capable of scooping and dumping operations by the extension and retraction of the bucket cylinder C4. As shown in Figure 2, the swing cylinder C1 is located at the lower front of the turntable 2 and connects the machine frame of the turntable 2 to the swing bracket 2B. As shown in Figures 1, 2, and 4, the boom cylinder C2 is located at the base end of the lower surface of the boom 21 (the front base end of the boom 21 when it is raised upward) and connects the swing bracket 2B to the boom 21. The arm cylinder C3 is located on the upper tip side of the boom 21 (the rear tip side of the boom 21 when it is raised upwards) and connects the boom 21 and the arm 22. The bucket cylinder C4 is located on the upper side of the arm 22 (the front side of the arm 22 when it is folded downwards) and connects the arm 22 and the bucket 23.

[0035] The hydraulic cylinder 24 is fitted with a cylinder cover 25 that protects the cylinder rod 32 of the hydraulic cylinder 24. In this embodiment, the cylinder cover 25 is provided at three locations: the boom cylinder C2, the arm cylinder C3, and the bucket cylinder C4. However, it may also be provided at two locations: the arm cylinder C3 and the bucket cylinder C4, or at only one location: the boom cylinder C2, the arm cylinder C3, or the bucket cylinder C4.

[0036] Although the swing cylinder C1, boom cylinder C2, arm cylinder C3, and bucket cylinder C4 differ in stroke length, pressure performance, and mounting position, their overall basic configuration is the same. Therefore, the basic configuration of the hydraulic cylinder 24 will be explained below using the bucket cylinder C4 as an example. As shown in Figure 5, the bucket cylinder C4 has a cylinder tube 31 and a cylinder rod 32. The cylinder tube 31 is a cylindrical body, and its base end 31e is connected to the front upper end of the bucket 23. The cylinder rod 32 is a cylindrical shaft, and is inserted and held inside the cylinder tube 31, protruding in the extension direction from the tip 31f of the cylinder tube 31. That is, the cylinder rod 32 is inserted and held inside the cylinder tube 31 so as to be slidable in the extension direction of its axis L2. The base end 32e of the cylinder rod 32 is inserted inside the cylinder tube 31, and its tip 32f is connected to the front of the arm 22.

[0037] As shown in Figures 1, 2, and 4, the working device 4 has a first cylinder bracket 71, a second cylinder bracket 72, a third cylinder bracket (cylinder bracket) 73, and a fourth cylinder bracket 74. The first cylinder bracket 71 is provided on the first surface portion 21A of the circumferential surface of the boom 21. The second cylinder bracket 72 is provided on the second surface portion 21B of the circumferential surface of the boom 21. The third cylinder bracket 73 is provided at the base end of the arm 22. The fourth cylinder bracket 74 is provided at the base end of the bucket 23.

[0038] The boom cylinder C2 has the tip 32f of the cylinder rod 32 pivotally connected to the first cylinder bracket 71, and the base end 31e of the cylinder tube 31 pivotally connected to the swing bracket 2B. The arm cylinder C3 has the tip 32f of the cylinder rod 32 pivotally connected to the third cylinder bracket 73, and the base end 31e of the cylinder tube 31 pivotally connected to the second cylinder bracket 72. The bucket cylinder C4 has the tip 32f of the cylinder rod 32 pivotally connected to the third cylinder bracket 73, and the base end 31e of the cylinder tube 31 pivotally connected to the fourth cylinder bracket 74. The detailed structure of the third cylinder bracket 73 will be described later.

[0039] <Cylinder cover> As shown in Figure 5, the cylinder cover 25 of this embodiment comprises a cover body 33 and a guide portion 25E. The guide portion 25E also comprises a guide plate 34 and an end cap (end portion) 35. The cover body 33 is a long frame with a flattened, approximately U-shaped cross-section, and is provided on the front side of the bucket cylinder C4 (outside the cylinder rod 32) extending in the same direction as the axis L2, that is, in the same direction as the extension direction of the cylinder rod 32 (hydraulic cylinder 24). For the purpose of describing the cylinder cover 25, the extension direction of the cylinder rod 32 (extension direction of the axis L2) is referred to as the length direction of the cylinder cover 25, the width direction of the cover body 33 that is perpendicular to the extension direction of the cylinder rod 32 is referred to as the lateral width direction of the cylinder cover 25, and the thickness direction of the cover body 33 that is perpendicular to the extension direction of the cylinder rod 32 is referred to as the vertical width direction of the cylinder cover 25.

[0040] The base end portion 33e of the cover body 33 is fixed to the connection portion J1 between the tip portion 32f of the cylinder rod 32 and the arm 22 by bolts 38 from the direction normal to the support surface of the connection portion J1. That is, the cover body 33 is configured so that its base end portion (first end side) 33e is attached to the tip side (connection portion J1) of the cylinder rod 32 by bolts 38, and is movable together with the cylinder rod 32 in accordance with the extension and retraction of the hydraulic cylinder 24. On the outer surface (cover outer surface) 33a of the cover body 33, which is the surface opposite to the cylinder tube 31, there is a V-shaped reinforcing rib 36 formed to be convex outward in the vertical direction (direction normal to the outer surface 33a). The reinforcing rib 36 extends in the longitudinal direction along the center of the lateral direction of the cover outer surface 33a. In this embodiment, as shown in Figure 6, the reinforcing rib 36 is made of a separate component from the cover body 33 and is fixed to the outer surface 33a of the cover by welding or the like. However, it may also be integrally formed in the central part of the outer surface 33a of the cover in the width direction by bending or pressing. A slide groove 37 with a U-shaped cross-section is provided on the inner surface side of the cover body 33, which is the surface facing the cylinder tube 31. The slide groove 37 extends in the longitudinal direction along the side edge 33b in the width direction of the cover body 33 and opens towards the center side (inward in the width direction) of the cover body 33 in the width direction.

[0041] The guide plate 34 is a rectangular plate that is elongated in the width direction of the cylinder cover 25, and is provided on the outer surface of the cylinder tube 31, extending in the tangential direction of the outer surface of the cross-section perpendicular to the extension direction of the cylinder tube 31. That is, the guide plate 34 is fixed to the cylinder tube 31 with its short end faces (guide ends) 41 on both sides protruding circumferentially from the outer surface of the cylinder tube 31 (see Figure 6). End caps 35 are attached to the guide ends 41. As shown in Figure 6, each guide end 41 is inserted into the slide groove 37 from the center side (inside) in the width direction of the cover body 33. As a result, the cover body 33 is engaged with and held to the cylinder cover 25 so as to be slidable in the length direction (axis L2 direction). In this configuration, the end cap 35 has a first side surface (first cap side surface) 42, which is the side opposite to the cylinder tube 31, that contacts and engages with the side of the slide groove 37 opposite to the cylinder tube 31 (first portion) 37a, and a second side surface (second cap side surface) 43, which is the side facing the cylinder tube 31, that contacts and engages with the side facing the cylinder tube 31 (third portion) 37c. In this embodiment, both the first cap side surface 42 and the second cap side surface 43 are formed in a planar shape.

[0042] The end cap 35 is a flat cap body having an insertion hole in its inner end face 44 for inserting the guide plate 34, and is fixed by being placed over the guide end 41. As shown in Figure 7, the tangential end face (cap end face) 45 of the end cap 35 is formed in a substantially V shape such that when viewed from the direction normal to the plate surface of the guide plate 34, it is convex toward the inner surface portion 37b of the slide groove portion 37.

[0043] The first curved convex portion 51, which is the protruding end of the cap end face 45, is curved in an arc shape so that when viewed from the direction normal to the surface of the guide plate 34, it is convex toward the inner surface portion 37b of the slide groove portion 37. The distance between the first curved convex portions 51 of the cap end faces 45 on both sides in the tangential direction (cap end dimension) W1 is set to be smaller than the spacing between the inner surface portions 37b of the groove on both sides in the tangential direction (inner surface portion dimension) W2. Therefore, a gap is formed between the first curved convex portion 51 and the inner surface portion 37b so that the first curved convex portion 51 is not in constant close contact with the inner surface portion 37b. The first curved convex portion 51 is formed in an arc shape that forms part of a circle with a diameter smaller than the inner surface portion dimension W2. In this embodiment, the first curved convex portion 51 is formed in an arc shape with the same diameter as the cap end dimension W1, and its arc center L3 coincides. In other words, the first curved convex portions 51 on both sides in the tangential direction are formed in a concentric arc shape.

[0044] On the cap end face 45, inclined surfaces 52 are provided on both sides of the first curved convex surface 51 in the direction of extension of the cylinder rod 32. Each inclined surface 52 is inclined such that it moves away from the groove inner surface (second portion) 37b as it moves away from the first curved convex surface 51 in the direction of extension of the cylinder rod 32. In this embodiment, the inclined surface 52 is inclined by 5 degrees from the direction parallel to the axis L2. Furthermore, the inclined surface 52 extends in the tangential direction of the outer circumference of the first curved convex surface 51. That is, the inclined surface 52 is formed continuously from the outer circular arc surface of the first curved convex surface 51 in the tangential direction. Also, as shown in Figure 6, both the corner 53 on the opposite side of the cylinder tube 31 and the corner 54 on the cylinder tube 31 side of the cap end face 45 are formed as tapered surfaces at approximately 45 degrees. In other words, the cap end face 45 is formed such that both the corner 53 on the opposite side of the cylinder tube 31 and the corner 54 on the cylinder tube 31 side in a cross section perpendicular to the extension direction of the cylinder rod 32 are chamfered. Therefore, a predetermined gap is defined between the corners 53 and 54 and the inner corner of the slide groove 37.

[0045] In this embodiment, the end cap 35 is made of a synthetic resin material such as polyvinyl chloride resin or polycarbonate resin. On the other hand, the cover body 33 is made of a metal material such as iron or stainless steel. That is, the end cap 35 and the cover body 33 are made of dissimilar materials. Furthermore, the end cap 35 may be made of an elastic material. This makes it possible to suppress noise, damage, deformation, etc. caused by friction or contact between the end cap 35 and the cover body 33.

[0046] <Cylinder bracket> As shown in Figures 4 and 8, the third cylinder bracket (cylinder bracket) 73 has a bracket side plate 75 and a cover plate 76. The bracket side plate 75 is a substantially flat plate and is provided in pairs spaced apart on the first surface portion 22A of the circumferential surface of the arm 22. The tip portion 32f of the cylinder rod 32 of the arm cylinder C3 and the tip portion 32f of the cylinder rod 32 of the bucket cylinder C4 are pivotally supported while being sandwiched between the bracket side plates 75.

[0047] The bracket side plates 75 are made of thick metal plates with high bending rigidity so as not to bend due to the stress applied from the arm cylinder C3 and bucket cylinder C4 while the work device 4 is being driven. As shown in Figure 8, the space S1 between the bracket side plates 75 houses a potentiometer 55 for detecting the amount of oscillation of the arm 22 and bucket 23, and hydraulic hoses 56 for guiding hydraulic fluid to each hydraulic cylinder 24. Therefore, the bracket side plates 75 also serve to protect the potentiometer 55, hydraulic hoses 56, etc. from collisions with external objects.

[0048] The bracket side plate 75 has a weight-reducing section 77. In this embodiment, the weight-reducing section 77 is a notch formed in a substantially arc shape when viewed from the direction normal to the surface of the bracket side plate 75 at the leading edge 75a of the bracket side plate 75. The weight-reducing section 77 is formed in a position and size that does not overlap with the mounting sections of the potentiometer 55, hydraulic hose 56, etc., when viewed from the direction normal to the surface of the bracket side plate 75. The weight-reducing section 77 may also be a through hole that penetrates between the surfaces of the bracket side plate 75.

[0049] A cover support portion 78 is horizontally positioned between the left and right bracket side plates 75. The cover support portion 78 is a substantially flat plate and is supported and fixed to the surface of each bracket side plate 75 on the side of the separated portion S1. The cover support portion 78 is provided with screw holes 80 into which cover fixing screws 79 can be screwed in. The cover fixing screws 79 are screwed into the screw holes 80 from the direction normal to the plate surface of the cover support portion 78, sandwiching the cover plate 76 between them. In other words, the cover plate 76 is connected and fixed to the cover support portion 78 by the cover fixing screws 79.

[0050] The cover support portion 78 is positioned near the tip 32f of the cylinder rod 32 of the arm cylinder C3, and near the tip edge 75a of the bracket side plate 75 at the tip 32f of the cylinder rod 32 of the bucket cylinder C4.

[0051] The cover support portion 78 on the bucket cylinder C4 side is positioned outward in the extension direction of the cover body 33 (towards the center of the third cylinder bracket 73) from the base end portion 33e of the cylinder cover 25. In other words, the cover support portion 78 is provided in a position that does not overlap with the mounting portion of the bolt 38 when viewed from the axial direction (first direction) of the bolt 38 that attaches the base end portion 33e of the cylinder cover 25 to the connection portion J1.

[0052] The cover plate 76 is a metal plate that is thinner and lighter than the bracket side plate 75, and is supported and fixed along the inside of the leading edge 75a of the bracket side plate 75. The cover plate 76 covers the space S1 between the bracket side plates 75 from the leading edge 75a side of the bracket side plate 75. The cover plate 76 has a cover body 81, a fixing piece 82, and a lid piece 83.

[0053] The cover body 81 is formed in the shape of a rectangular flat plate with a left-right width dimension approximately the same as the separation portion S1. The fixing piece 82 is a rectangular flat plate piece and is provided on both short edges of the cover body 81. The fixing piece 82 has a screw insertion hole 84 through which the cover fixing screw 79 can be inserted. The fixing piece 82 is supported in a face-to-face state with the cover support portion 78 and is fixed by the cover fixing screw 79. That is, as shown in Figure 9, the cover plate 76 is fixed in a position that does not overlap with the mounting portion of the bolt 38 when viewed from the axial direction (first direction) of the bolt 38 that fixes the base end portion 33e of the cylinder cover 25 to the connection portion J1. As a result, the cylinder cover 25 can be replaced without removing the cover plate 76 from the cover support portion 78.

[0054] The cover piece 83 is a plate piece having an edge shape substantially the same as the cutout portion 77 of the bracket side plate 75, and is provided on both long edges of the cover body 81. The cover piece 83 is formed by bending toward one side of the plate surface of the cover body 81. In this way, the cover piece 83 is formed in a substantially arc shape when viewed from the direction normal to the plate surface of the bracket side plate 75, and when the cover plate 76 is attached to the bracket side plate 75 as described above, it covers the entire cutout portion 77 from the inside of the bracket side plate 75. This prevents foreign matter such as soil and dust from entering the separated portion S1.

[0055] In this embodiment, each of the cover pieces 83 is bent approximately 90 degrees in the direction normal to one of the plate surfaces of the cover body 81. As a result, the cover plate 76 has higher rigidity than a simple flat plate. Moreover, when the cover plate 76 is attached to the bracket side plate 75, the cover pieces 83 are pressed against the inside of the bracket side plate 75 by the restoring force against their bending. That is, the cover pieces 83 can cover the weight-reducing portion 77 in close contact with the inside of the bracket side plate 75. As a result, the intrusion of foreign matter into the separated portion S1 can be suppressed more effectively.

[0056] <Other Embodiments> In the above embodiment, the first curved convex portion 51 is formed in an arc shape with the same diameter as the distance between the cap ends W1. However, if it is possible to reduce the contact resistance between the end cap 35 and the slide groove portion 37, it may be formed in an arc shape with a smaller diameter than the distance between the cap ends W1 (for example, a semicircular small-diameter convex shape).

[0057] Furthermore, in the above embodiment, the first curved convex portions 51 of the end caps 35 on both sides in the tangential direction are formed in a concentric arc shape. However, if it is possible to reduce the contact resistance between the end cap 35 and the slide groove portion 37, the first curved convex portions 51 of the end caps 35 on both sides in the tangential direction may be formed eccentrically in the direction of extension of the cylinder rod 32 or perpendicular to the direction of extension when viewed from the direction normal to the surface of the guide plate 34.

[0058] Furthermore, in the above embodiment, the cap end face 45 is formed in a V-shape when viewed from the direction normal to the surface of the guide plate 34, and the adjacent surfaces (inclined surfaces) 52 on both sides of the first curved convex surface 51 in the extension direction of the cylinder rod 32 are inclined surfaces. However, if it is possible to prevent parts of the end cap 35 other than the first curved convex surface 51 from contacting the inner surface 37b of the groove when an angular displacement occurs in the extension direction of the slide groove 37 relative to the guide plate 34, the adjacent surfaces 52 may be formed in a planar shape substantially parallel to the inner surface 37b of the groove.

[0059] In the above embodiment, the end cap 35 is configured such that the surface opposite to the cylinder tube 31 (first cap side surface) 42 and the surface on the cylinder tube 31 side (second cap side surface) 43 are both formed in a planar shape and make surface contact with the first portion 37a and the third portion 37c of the slide groove 37. However, as shown in Figure 10, a second curved convex surface portion 61 is provided on at least one of the first cap side surface 42 and the second cap side surface 43, which is curved so as to be convex in the direction normal to the surface of the guide plate 34. The second curved convex surface portion 61 may also be formed in an arc shape in cross-section perpendicular to the extension direction of the cylinder rod 32. Furthermore, the second curved convex surface portion 61 may be formed only in the central part of the first cap side surface 42 and the second cap side surface 43, or it may be formed over the entire surface between the left and right sides of the first cap side surface 42 and the second cap side surface 43. Furthermore, if the contact resistance between the end cap 35 and the slide groove 37 can be reduced, the second curved convex portion 61 may be formed in a spherical shape or in an arc shape when viewed from the tangential direction. In addition, multiple second curved convex portions 61 may be provided on the first side surface 42 and the second side surface 43 of the cap.

[0060] Furthermore, although the above embodiment describes a configuration in which end caps (end portions) 35 are attached to both ends of the guide plate 34, the configuration of the end portions is not limited to this. For example, the end portions may have a different shape from the cap shape, or the end portions may be integrally formed with the guide plate 34.

[0061] <Effects> As described above, the cylinder cover 25 of the above embodiment is a cylinder cover 25 that is attached to a hydraulic cylinder 24 and protects the cylinder rod 32 of the hydraulic cylinder 24, and comprises a cover body 33 whose first end side (base end 33e) is attached to the tip side (connection part J1) of the cylinder rod 32 and moves together with the cylinder rod 32 in accordance with the extension and retraction of the hydraulic cylinder 24, and a guide part 25E that supports the cover body 33 so as to be slidable along the extension direction of the cylinder rod 32, and the guide part 25E comprises a guide plate 34 that is provided on the outer circumference of the cylinder tube 31 of the hydraulic cylinder 24 and extends in the tangential direction of the outer circumference of the cross section perpendicular to the extension direction of the cylinder tube 31, and The cover body 33 comprises a pair of end portions (end caps) 35 provided at both ends (guide ends) 41 in the tangential direction of the side plate 34, and the cover body 33 has a first portion 37a facing the first side surface (first cap side surface) 42 which is the side of the end portion 35 opposite to the cylinder tube 31, a second portion (groove inner side surface) 37b facing the tangential end surface (cap end surface) 45 of the end portion 35, and a third portion 37c facing the second side surface (second cap side surface) 43 which is the side of the end cap 35 that faces the cylinder tube 31, and the end portion 35 has a first curved convex surface portion 51 on the end surface 45 which is curved to be convex toward the second portion 37b.

[0062] This configuration allows for a smaller gap between the end face 45 of the end portion 35 and the second portion (groove inner side portion) 37b of the cover body 33, as well as a reduced contact resistance between the end face 45 and the second portion 37b. This suppresses the generation of abnormal noise and vibration, and enables smooth operation.

[0063] Furthermore, the first curved convex portion 51 is formed in an arc shape when viewed from the direction normal to the surface of the guide plate 34. This configuration allows for a smaller contact resistance between the end portion 35 and the cover body 33, resulting in smoother operation.

[0064] Furthermore, the first curved convex portion 51 is formed in an arc shape that forms part of a circle with a diameter smaller than the distance W2 between the second portions (groove inner surface portions) 37b provided on both sides of the cover body 33 in the tangential direction. If the radius of curvature of the first curved convex portion 51 is large, the contact area will increase with deformation depending on the material of the end portion 35. However, with the above configuration, the contact area between the end portion 35 and the cover body 33 can be reduced, thus enabling smoother operation.

[0065] Furthermore, the first curved convex portions 51 of each end portion 35 provided on both sides in the tangential direction are formed in a concentric arc shape. With this configuration, the stress when the first curved convex portion 51 of each end portion 35 contacts the second portion 37b is concentrated in the same central direction, making it difficult for the cover body 33 to shift in the sliding direction. Therefore, the generation of abnormal noise and vibration can be suppressed, and smoother operation is also possible.

[0066] Furthermore, the end face 45 has inclined surfaces 52 on both sides of the first curved convex surface 51 in the direction of extension of the cylinder rod 32, such that the further it moves away from the first curved convex surface 51 in the direction of extension of the cylinder rod 32, the further it moves away from the second portion 37b. With this configuration, even if there is an angular misalignment in the direction of extension of the cover body 33 relative to the guide plate 34, the parts of the end portion 35 other than the first curved convex surface 51 are less likely to come into contact with the second portion 37b, thus reducing the contact resistance between the end portion 35 and the cover body 33. As a result, the generation of abnormal noise and vibration can be further suppressed, and smoother operation is also possible.

[0067] Furthermore, the end face 45 has a curved shape such that the cross-sectional shape perpendicular to the extension direction of the cylinder rod 32 is convex toward the second portion 37b, or the corner 53 on the opposite side of the cylinder tube and the corner 54 on the cylinder tube 31 side of the cross-sectional shape perpendicular to the extension direction of the cylinder rod 32 are chamfered. With this configuration, the contact resistance between the end portion 35 and the cover body 33 can be reduced, allowing for smoother operation.

[0068] In another embodiment, the end portion 35 may be provided with a second curved convex portion 61 on at least one of the first side surface 42 and the second side surface 43, which is curved to be convex in the direction normal to the surface of the guide plate 34. With this configuration, the second curved convex portion (support projection) 61 provided on the first side surface 42 or the second side surface 43 of the end portion 35 contacts the opposing surface portion (first portion 37a or third portion 37c) of the cover body 33, thereby reducing the contact resistance between the end portion 35 and the cover body 33. As a result, smoother operation becomes possible.

[0069] Furthermore, the second curved convex portion 61 has an arc-shaped cross-section perpendicular to the extension direction of the cylinder rod 32. This configuration allows for reduced contact resistance between the end portion 35 and the cover body 33, resulting in smoother operation.

[0070] Furthermore, the end portion 35 may be made of a resin material. This configuration reduces contact noise and friction noise between the end portion 35 and the cover body 33.

[0071] Furthermore, the hydraulic cylinder 24 of this embodiment is fitted with the cylinder cover 25 with the above configuration. This configuration makes it possible to realize a hydraulic cylinder that can operate smoothly while properly protecting the cylinder rod 32 of the hydraulic cylinder 24.

[0072] Furthermore, the work machine 1 of this embodiment comprises a machine body (turntable) 2 and a work device 4 attached to the machine body 2, and the work device 4 is equipped with a hydraulic cylinder 24 with the above configuration. With this configuration, the cylinder rod 32 of the hydraulic cylinder 24 can be properly protected while the work device 4 can be operated smoothly, thus realizing a work machine that can operate stably over a long period of time.

[0073] Furthermore, the working device 4 has a cylinder bracket 73 that supports the first end 32f at the tip of the cylinder rod 32. The cylinder bracket 73 is erected spaced apart in one direction and has a pair of bracket side plates 75 that clamp the first end 32f, and a cover plate 76 that covers the spaced portion S1 between the bracket side plates 75. The bracket side plates 75 have weight-reducing cutouts 77, and the cover plate 76 has a lid piece 83 that covers the weight-reducing cutouts 77.

[0074] Generally, the cylinder bracket 73 is made of a thick metal plate with high rigidity so that it does not easily deform due to the stress applied from the hydraulic cylinder 24 while the work device 4 is being driven. However, this increases the overall weight of the work device 4, impairing its maneuverability. In contrast, with the above configuration, the weight reduction portion 77 provided in the bracket side plate 75 makes the cylinder bracket 73 lighter, thus improving the maneuverability of the work device 4. Moreover, with this configuration, the cover plate 76 prevents foreign matter such as soil and dust from entering the gap S1 between the bracket side plates 75 from the weight reduction portion 77, thus improving the operational stability of the work device 4.

[0075] Furthermore, the lid piece 83 is formed by bending a part of the cover plate 76.

[0076] With this configuration, even if a relatively thin and lightweight plate material is used, the overall rigidity of the cover plate 76 can be increased, making it possible to further reduce the weight of the cylinder bracket 73.

[0077] Furthermore, the first end of the cylinder cover 25 is attached to the tip of the cylinder rod 32 from the first direction by a bolt 38, and the cover plate 76 is positioned so as not to overlap with the mounting portion of the bolt 79 when viewed from the first direction.

[0078] With the above configuration, the cylinder cover 25 can be installed and removed without removing the cover plate 76 from the cover support part 78, thus improving maintainability.

[0079] Furthermore, the weight-reducing portion 77 is a notch formed in the leading edge portion 75a of the bracket side plate 75.

[0080] With the above configuration, a wider area for forming the weight-reducing portion 77 can be secured, making it possible to further reduce the weight of the cylinder bracket 73. This further improves the mobility of the work device 4.

[0081] The work machine 1 comprises a machine body 2 and a work device 4 attached to the machine body 2. The work device 4 includes a hydraulic cylinder 24 for driving the work device 4 and a cylinder bracket 73 for supporting the first end 32f of the hydraulic cylinder 24. The cylinder bracket 73 has a pair of bracket side plates 75 that are spaced apart in one direction and clamp the first end 32f, and a cover plate 76 that covers the spaced portion S1 between the bracket side plates 75. The bracket side plates 75 have weight-reducing cutouts 77, and the cover plate 76 has a cover piece 83 that covers the weight-reducing cutouts 77.

[0082] With the above configuration, the weight reduction of the cylinder bracket 73 can be achieved by the weight reduction cutouts 77 provided in the bracket side plate 75, thereby improving the mobility of the work device 4. Moreover, with this configuration, the cover plate 76 prevents foreign matter such as soil and dust from entering the gap S1 between the bracket side plates 75 from the weight reduction cutouts 77, thus improving the operational stability of the work device 4.

[0083] Having described the present invention above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended to be included.

[0084] Furthermore, although the embodiments described above illustrate the application of the present invention to work machines such as backhoes, the scope of application of the present invention is not limited to these. For example, it may be applied to other construction machinery such as wheel loaders, compact track loaders, and skid steer loaders, or to agricultural machinery such as tractors, combine harvesters, rice transplanters, and lawnmowers. [Explanation of symbols]

[0085] 1. Work machine 2. Turntable (aircraft) 3. Traveling device 4. Working equipment 21 Boom 22 Arms 23 Work Tools 24 Hydraulic Cylinders 25 Cylinder Cover 25E Guide Section 31 Cylinder tube 32 Cylinder rod 32f Tip (1st end) 33 Cover body 33b Side edge 34 Guide Plate 35 End cap (end section) 37 Slide groove 37a Part 1 37b Groove inner side surface (second part) 37c Part 3 41 Guide end (end) 42 Cap, first side (first side) 43 Cap, second side (second side) 45 Cap end face (end face) 51 1st curve convex part 52 Slope section 53 Corner 54 corners 73. Third cylinder bracket (cylinder bracket) 75 Bracket side panel 76 Cover plate 77. Weight reduction section 83 Lid piece W2 Separation width

Claims

1. A cylinder cover that is attached to a hydraulic cylinder and protects the cylinder rod of the hydraulic cylinder, A cover body, the first end of which is attached to the tip of the cylinder rod, moves together with the cylinder rod in accordance with the extension and retraction of the hydraulic cylinder, The cover body is provided with a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, The aforementioned guide portion is A guide plate is provided on the outer circumference of the cylinder tube of the hydraulic cylinder, extending in the tangential direction of the outer circumference of the cross-section perpendicular to the extension direction of the cylinder tube, The guide plate comprises a pair of end portions provided at both ends in the tangential direction, The cover body has a first portion facing the first side surface, which is the side of the end portion opposite to the cylinder tube, a second portion facing the tangential end surface of the end portion, and a third portion facing the second side surface, which is the side of the end portion facing the cylinder tube. The end portion has a first curved convex portion on its end face that is curved to be convex toward the second portion, The first curved convex portions of each end are formed in a concentric arc shape when viewed from the direction normal to the surface of the guide plate, in a cylinder cover.

2. A cylinder cover that is fitted to a hydraulic cylinder and protects the cylinder rod of the hydraulic cylinder, A cover body, the first end of which is attached to the tip of the cylinder rod, moves together with the cylinder rod in accordance with the extension and retraction of the hydraulic cylinder, The cover body is provided with a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, The aforementioned guide portion is A guide plate is provided on the outer circumference of the cylinder tube of the hydraulic cylinder, extending in the tangential direction of the outer circumference of the cross-section perpendicular to the extension direction of the cylinder tube, The guide plate comprises a pair of end portions provided at both ends in the tangential direction, The cover body has a first portion facing the first side surface, which is the side of the end portion opposite to the cylinder tube, a second portion facing the tangential end surface of the end portion, and a third portion facing the second side surface, which is the side of the end portion facing the cylinder tube. The end portion has a first curved convex portion on its end face that is curved to be convex toward the second portion, The first curved convex portion is a cylinder cover in which the shape, when viewed from the direction normal to the surface of the guide plate, is formed in the shape of an arc that forms part of a circle with a diameter smaller than a circle whose diameter is the distance between the second portions provided on both sides of the cover body in the tangential direction.

3. The cylinder cover according to claim 2, wherein the first curved convex portions of each end provided on both sides in the tangential direction are formed in a concentric arc shape.

4. The cylinder cover according to claim 3, wherein the end face has inclined surfaces on both sides of the first curved convex surface in the direction of extension of the cylinder rod, such that the distance from the second portion increases as the distance from the first curved convex surface in the direction of extension of the cylinder rod increases.

5. The cylinder cover according to claim 3, wherein the end face has a curved shape such that the cross-sectional shape perpendicular to the extension direction of the cylinder rod is convex toward the second portion, or the corner opposite to the cylinder tube and the corner on the cylinder tube side of the cross-sectional shape perpendicular to the extension direction of the cylinder rod are chamfered.

6. The cylinder cover according to claim 1, wherein the end portion is provided with a second curved convex portion on at least one of the first side surface and the second side surface, which is curved to be convex in the direction normal to the surface of the guide plate.

7. The cylinder cover according to claim 6, wherein the second curved convex portion has a cross-sectional shape perpendicular to the extension direction of the cylinder rod, which is formed in an arc shape.

8. The cylinder cover according to claim 1, wherein the end portion is formed of a resin material.

9. A hydraulic cylinder fitted with a cylinder cover according to any one of claims 1 to 8.

10. The system comprises an aircraft body and a work device attached to the aircraft body, The work device is a work machine equipped with the hydraulic cylinder described in claim 9.

11. comprising a machine body and a work device attached to the machine body, The aforementioned work apparatus is Hydraulic cylinder and A cylinder cover is attached to the hydraulic cylinder to protect the cylinder rod of the hydraulic cylinder, The cylinder has a cylinder bracket that supports the first end of the cylinder rod on the tip side, The cylinder cover is A cover body, the first end of which is attached to the tip of the cylinder rod, moves together with the cylinder rod in accordance with the extension and retraction of the hydraulic cylinder, The cover body is provided with a guide portion that slidably supports the cover body along the extension direction of the cylinder rod, The aforementioned guide portion is A guide plate is provided on the outer circumference of the cylinder tube of the hydraulic cylinder, extending in the tangential direction of the outer circumference of the cross-section perpendicular to the extension direction of the cylinder tube, The guide plate comprises a pair of end portions provided at both ends in the tangential direction, The cover body is, A first portion facing the first side surface, which is the side of the end portion opposite to the cylinder tube, The second portion of the end portion facing the tangential end face, It has a third portion that faces the second side surface, which is the surface on the cylinder tube side of the end portion, The end portion has a first curved convex portion on its end face that is curved to be convex toward the second portion, The aforementioned cylinder bracket is A pair of bracket side plates are erected spaced apart in one direction and clamp the first end, It has a cover plate that covers the space between the bracket side plates, The bracket side plate has a weight-reducing portion, The cover plate is a work machine having a lid piece that covers the weight-reducing portion.

12. The work machine according to claim 11, wherein the lid piece is formed by bending a part of the cover plate.

13. The first end of the cylinder cover is attached to the tip of the cylinder rod by a bolt from the first direction. The work machine according to claim 11, wherein the cover plate is provided in a position that does not overlap with the bolt mounting portion when viewed from the first direction.

14. The work machine according to claim 11, wherein the weight-reducing portion is a notch formed in the leading edge of the bracket side plate.

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