JP2013133093A - Rod protective structure of hydraulic cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate both disadvantages of a prior art dust boot and anti-dust cover by applying a structure for protecting a hydraulic cylinder rod used for driving a steering wheel of a steering axle of an industrial vehicle etc.SOLUTION: There are provided: a dust boot 5 having a bellows-like cylindrical body 5a that is disposed at a rod 4c of a hydraulic cylinder 4, that can be extended or retracted and has a length of its maximum extended state which is shorter than a stroke length of the rod 4c, having one end fixed to a rod end of the hydraulic cylinder 4, the another end that is a free end and an engagement part 5c protruding in a radial direction being formed at the free end; and an anti-dust cover 6 fixed to an axle beam 2, having a cylindrical body 5a of the dust boot 5 inserted thereinto to allow the cylindrical body to move and in turn formed with an insertion part to be engaged with the engagement part 5c, the engagement part 5c being engaged with the insertion part when the rod of the hydraulic cylinder 4 is extended to cause the cylindrical body 5a to be extended.

Description

  The present invention relates to a structure for protecting a rod of a hydraulic cylinder for turning wheels fixed to a turning axle of an industrial vehicle such as a forklift or a construction vehicle.

  Conventionally, as shown in FIGS. 9 to 11, an all-hydraulic rear axle is supported on a vehicle body frame (not shown) so as to be swingable by a center pin 3 projecting forward and backward, and the rear axle beam 2 is The center has a hydraulic cylinder 4 and the left and right opposite turning wheels 7, the rim 8 and the hub 9 are centered on left and right knuckles 10 and a king pin 11 which can rotate substantially perpendicular to the ground on both ends of the rear axle beam 2. is set up. The left and right knuckle 10 is configured by connecting the arm 12 of the knuckle 10 and the rod end of the hydraulic cylinder 4 with a yoke 13.

  However, there are cases where dirt such as mud and wet waste paper is scattered and deposited on the road surface in the environment where the vehicle is used. In such a usage environment, the dust on the road surface is often scooped up by the rotating wheel 7 that rotates while the vehicle is running and adheres to the rod 4c of the hydraulic cylinder 4. In particular, when wet waste paper or the like adheres to the rod 4c, it is dried and firmly fixed.

  A large amount of such dust adheres to the rod 4c, and thus passes or damages the dust seal of the cylinder cap 4b, damages the packing inside the cylinder, and finally causes a problem of oil leakage of the hydraulic cylinder 4.

  Therefore, as shown in FIGS. 12 and 13, a cover 6X is installed in a portion where the hydraulic cylinder 4 is mounted between the upper flange plate 2a (FIG. 13) and the lower flange plate 2b of the rear axle beam 2, and dust A structure to prevent this has been proposed.

  The cover 6X shown in FIGS. 12 and 13 can be manufactured at low cost, but the sliding of the arm 12 of the knuckle 10 and the yoke according to the expansion and contraction of the hydraulic cylinder 4 when the turning wheel 7 (see FIG. 11) is steered. Since 13 moves, there are many portions that do not cover the rod 4c, that is, there are many gaps in which dust enters, which is not sufficient as dust removal. As an improvement, for example, a cylinder cover for an industrial vehicle disclosed in Patent Document 1 is also known. However, this also does not sufficiently cover the rod of the hydraulic cylinder, and is still unacceptable as dust removal. It was enough.

  As a structure for completely covering the rod of the hydraulic cylinder 4, a structure in which a dust boot 5X is put on the rod 4 as shown in FIGS. 14 and 15 is known. The material of the dust boot 5X is rubber, cloth, or general-purpose resin. This type of dust boot is mainly bellows-shaped, and the insertion port side is fixed to the cylinder cap of the hydraulic cylinder 4 with a band 15. Such a dust boot 5X protects the rod of the hydraulic cylinder 4 by interlocking the bellows portion of the dust boot 5X with the expansion and contraction of the hydraulic cylinder 4.

  In such a dust boot 5X, the outer shape of the bellows part of the dust boot 5X becomes large according to the expansion / contraction distance. That is, when the maximum extension distance (stroke) of the rod of the hydraulic cylinder 4 becomes longer, the outer shape of the dust boot 5X becomes larger.

However, when the clearance CL (see FIG. 12) between the web plate 2c to which the hydraulic cylinder 4 of the rear axle beam 2 is fixed and the rod of the hydraulic cylinder 4 is small, the outer shape of the bellows portion of the dust boot 5X is increased. I can't. In order to increase the extension distance of the dust boot 5X and reduce the outer shape of the bellows portion, it is necessary to increase the number of bellows valleys. It is necessary to maintain a relationship of L _min > LB between the minimum length L _min when the rod is reduced (see FIG. 11) and the minimum length LB when the dust boot is reduced. Since the thickness of the material of the dust boot 5X is overlapped when the boot is reduced, the relationship of L _min > LB may not be maintained. In such a case, the dust boot 5X is crushed when the rod is reduced. May end up. In the relationship of L _min <LB, a problem of early wear of the dust boot 5X occurs due to interference between the boot end 5e and the yoke 13.

JP 2006-160151 A

  The present invention can overcome the disadvantages of both the conventional dust boot and the conventional dust-removal cover as a structure for protecting the rod of the hydraulic cylinder used for the turning wheel drive of the turning axle of an industrial vehicle or the like from dust. The main object is to provide a rod protection structure for a hydraulic cylinder.

  In order to achieve the above object, the present invention provides a rod protection structure for a diverting wheel drive hydraulic cylinder fixed to an axle beam, which is attached to the rod of the hydraulic cylinder and is extendable and retractable at the maximum extension. An engaging portion protruding in the radial direction has a bellows-like cylindrical body whose length is shorter than the stroke length of the rod, one end is fixed to the rod end of the hydraulic cylinder and the other end is a free end. It is fixed to at least one of the dust boot formed at the free end, the axle beam and the cylinder main body of the hydraulic cylinder, and allows the cylindrical main body to move by inserting the cylindrical main body of the dust boot. On the other hand, an insertion portion that is engaged with the engagement portion is formed, and dust that extends the cylindrical body by engaging the engagement portion with the insertion portion when the rod of the hydraulic cylinder is extended. Characterized in that it comprises a bar, a.

  The axle beam includes an upper and lower flange plate, a web plate that connects the upper and lower flange plates, and a center pin fixing plate that connects the upper and lower flange plates at an intermediate portion between the front and rear surfaces of the flange plate, The hydraulic cylinder is fixed to the web plate, the dust cover is fixed to an axle beam, and extends between the upper and lower flange plates from the end surface of the center pin fixing plate to the web plate. preferable.

  One end of the dust cover may be connected to the cylinder body of the hydraulic cylinder, and the insertion portion may be formed at the other end.

  The dust cover may have a box shape that covers a cylinder body of the hydraulic cylinder, and insertion portions may be formed on both end faces.

  According to the present invention, the length of the dust boot can be shortened compared to the conventional dust boot that completely covers the rod, and the rod portion exposed by shortening the dust boot can be covered with the dust cover. Even in the case of a hydraulic cylinder having a long stroke length, it is possible to almost prevent dust from adhering to the rod and protect the rod without causing damage to the constituent members.

FIG. 3 is a partial cross-sectional plan view taken along the line II of FIG. 2 showing a first embodiment of the hydraulic cylinder protection structure according to the present invention. It is a front view of FIG. FIG. 3 is a partial cross-sectional enlarged right side view taken along line III-III in FIG. 2. It is a principal part enlarged view of FIG. It is a fragmentary sectional top view which expands and shows the principal part of 2nd Embodiment of the protection structure of the hydraulic cylinder which concerns on this invention. It is a fragmentary sectional side view which shows 2nd Embodiment of this invention. It is a fragmentary sectional top view which shows 3rd Embodiment of the protection structure of the hydraulic cylinder which concerns on this invention. It is a fragmentary sectional top view which expands and shows the principal part of 4th Embodiment of the protection structure of the hydraulic cylinder which concerns on this invention. It is a partially omitted plan view showing a conventional rear axle. It is a front view of the rear axle of FIG. FIG. 2 is a partial cross-sectional plan view showing a steered wheel operating state of the rear axle of FIG. 1. It is a fragmentary sectional top view which shows the rod protection structure of the conventional hydraulic cylinder. It is a front view of the rod protection structure of FIG. It is a fragmentary sectional top view which shows the other example of the rod protection structure of the conventional hydraulic cylinder. It is a front view of the rod protection structure of FIG.

  A first embodiment of a hydraulic cylinder protection structure according to the present invention will be described below with reference to FIGS. In addition, about all embodiment including a prior art example, the same code | symbol is attached | subjected to the same component and duplication description may be abbreviate | omitted.

  1 is a partial cross-sectional plan view showing a protective structure of a hydraulic cylinder according to a first embodiment, FIG. 2 is a front view, FIG. 3 is a partial cross-sectional enlarged right side view, and FIG. 4 is an enlarged view of a main part of FIG. .

  The axle beam 2 of the rear axle 1 has a cross-sectional shape that is substantially H-shaped steel or substantially I-shaped steel, and upper and lower flange plates 2a and 2b are connected by a web plate 2c, and the front and rear surfaces of the flange plates 2a and 2b are connected. A center pin fixing plate 2d is connected between the upper and lower flange plates 2a, 2b at the intermediate portion, and the center pin 3 projects from the center pin fixing plate 2d in the front-rear direction.

  The hydraulic cylinder 4 is fixed to the web plate 2 c of the axle beam 2. The hydraulic cylinder 4 includes a cylinder body 4ab including a cylinder tube 4a and a cylinder cap 4b, and a rod 4c that expands and contracts. In the illustrated example, the cylinder caps 4b and 4b of the hydraulic cylinder 4 are screwed to the web plate 2c with fixing screws 4d. The illustrated hydraulic cylinder 4 is a double-acting cylinder having rods 4c and 4c on both sides, but can be replaced with two single-acting cylinders (not shown).

The dust boot 5 attached to the rod 4c of the hydraulic cylinder 4 is formed of rubber, cloth, general-purpose resin or the like, and can be expanded and contracted, and the length when fully extended (when fully extended) is the hydraulic cylinder 4. A fixed end having a bellows-like cylindrical main body 5a (FIG. 4) shorter than the stroke length _Lmax (see FIG. 11) and having one end fixed to the rod end (rod end surface) of the hydraulic cylinder 4 with a fixing screw 5s. 5b and the other end is a free end, and a locking portion 5c protruding in the radial direction is formed at the free end. The rod end of the rod 4c is provided with a rod end fitting 4e for pin connection with the yoke 13, and the fixed end 5b of the boot 5 is formed with a rectangular hole 5d (FIG. 3) through which the rod end fitting 4e is passed. Has been. The locking portion 5c can have a bowl shape, but may have other shapes. The stroke length _Lmax corresponds to the maximum extension length of the rod 4c.

The dust cover 6 is fixed to the upper and lower flange plates 2a and 2b of the axle beam 2 by fixing screws 6a. Dust cover 6 is formed of a metal plate, partially covers the end face 2d ₁ of the center pin fixing plate 2d toward the upper and lower flanges plate 2a, a rear side surface of the 2b on the left and right sides, the middle web plate 2c The rod 4c and the dust boot 5 are orthogonally crossed and an insertion portion 6b (FIG. 3) is formed on the intersecting surface. The dust cover 6 is designed to have a position and dimensions that do not interfere with the left and right turning wheels 7 and 7 at the angle position of the maximum steering angle (for example, 75 to 80 °) of the turning wheel 7 (see FIG. 11).

  The insertion portion 6b is formed by a U-shaped notch (see FIG. 3), and allows the movement of the cylindrical body 5a of the dust boot 5 within a certain range, while being engaged with the engagement portion 5c. The size and shape are such that the stopper 5c does not pass through. Therefore, when the rod 4c is extended by cutting the steering (not shown) from the state shown in FIG. 1 (straight forward steering position), the locking part 5c is locked to the edge of the insertion part 6b during the extension, The cylindrical main body 5a extends. The insertion portion 6b can also pass the yoke 13 when the rod 4c is contracted. The insertion part can also be formed by a through hole.

  According to the protective structure of the hydraulic cylinder having the above configuration, the maximum extension length of the bellows-like cylindrical main body 5a is shorter than the stroke length of the rod 4c, so that the locking portion 5c is inserted into the dust cover 6 when the rod 4c is extended. The dust boot 5 can be extended by engaging with the edge of the portion 6b. Further, when the rod 4 c is contracted, the dust boot 5 can be contracted by coming into contact with the cylinder cap 4 b of the hydraulic cylinder 4. Such a dust boot 5 can be made shorter than a conventional dust boot completely covering the rod 4c, so that the outer diameter can be kept small, and even a long stroke hydraulic cylinder can be crushed. Absent. Further, since one end of the dust boot 5 is fixed to the rod end, it does not interfere with the yoke 13 and is not damaged. The dust cover 6 and the dust boot 5 cooperate to close the rod 4c of the hydraulic cylinder 4 from the outside to prevent dust and other dust from adhering to the rod 4c.

  5 and 6 show a second embodiment of the protection structure for a hydraulic cylinder according to the present invention. In the second embodiment, the dust cover 6A is different from the dust cover 6 of the first embodiment. The dust cover 6A has a cross-sectional shape that matches the outer diameter of the cylinder cap 4b (in the figure, a U-shape), and one end contacts the outer peripheral surface of the cylinder cap 4b of the hydraulic cylinder 4, and the other end side An insertion portion 6b is formed on the end surface 6e. The dust cover 6 is in contact with the web plate 2c to form a closed space that prevents dust from entering the rod 4c. The dust cover 6A is fixed to the cylinder cap 4b with fixing screws 6s, but may be fixed to the web plate 2c by screwing or the like. Other configurations are the same as those in the first embodiment.

  FIG. 7 shows a third embodiment of the protective structure for the hydraulic cylinder according to the present invention. The dust cover 6B of the third embodiment is formed in a box shape that covers the entire cylinder body 4ab and extends to the left and right rods 4c, 4c, and has insertion portions 6b at both ends. Other configurations are the same as those of the second embodiment.

  FIG. 8 shows a fourth embodiment of the protective structure for the hydraulic cylinder according to the present invention. The fourth embodiment is a modification of the second embodiment, and the dust cover 6C has a cylindrical shape and forms a closed space by itself. The dust cover 6C is bonded and fixed to the cylinder cap 4b.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Rear axle 2 Axle beam 3 Center pin 4 Hydraulic cylinder 4ab Cylinder main body 4c Rod 5 Dust boot 5a Cylindrical main body 5c Locking part 6, 6A, 6B, 6C Dust cover 6b Insertion part

Claims (4)

A rod protection structure for a hydraulic cylinder for turning wheels fixed to an axle beam,
It has a bellows-like cylindrical body that is attached to the rod of the hydraulic cylinder and can be extended and contracted, and has a length at maximum extension shorter than the stroke length of the rod, and one end is fixed to the rod end of the hydraulic cylinder And the other end is a free end, and a dust boot in which a locking portion protruding in the radial direction is formed at the free end,
An insertion that is fixed to at least one of the axle beam and the cylinder main body of the hydraulic cylinder and that allows the cylindrical main body of the dust boot to pass therethrough and allows the cylindrical main body to move while locking to the locking portion. A dust cover that extends the cylindrical main body by locking the locking portion to the insertion portion when the rod of the hydraulic cylinder is extended,
A rod protection structure for a hydraulic cylinder, comprising: The axle beam includes an upper and lower flange plate, a web plate that connects the upper and lower flange plates, and a center pin fixing plate that connects the upper and lower flange plates at an intermediate portion between the front and rear surfaces of the flange plate,
The hydraulic cylinder is fixed to the web plate;
2. The rod protection according to claim 1, wherein the dust cover is fixed to an axle beam, and extends between the upper and lower flange plates from an end surface of the center pin fixing plate to the web plate. Construction.   The rod protection structure according to claim 1, wherein the dust cover has one end connected to a cylinder body of the hydraulic cylinder and the other end formed with the insertion portion. The rod protection structure according to claim 1, wherein the dust cover has a box shape covering a cylinder body of the hydraulic cylinder, and the insertion portions are formed on both end surfaces.

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