JP5898896B2 - Work machine shaft seal structure - Google Patents

Description

The present invention relates to a shaft seal structure in a shaft support mechanism that swingably holds a work member such as a bucket in a work machine that performs work by operating a work device with a hydraulic actuator.

As an example of the working machine as described above, a skid steer loader, a power shovel, and the like that are used when excavating the ground or moving the excavated earth and sand are widely known. For example, a power shovel is configured by providing a working device such as a boom, an arm, and a bucket on a vehicle body provided with a traveling device, and the traveling device and the working device are driven by a hydraulically driven actuator.

In the swing mechanism of the bucket of the work machine, even when a general shaft support mechanism is employed, the soil and the like that is handled in association with the excavation work or the moving work is not recovered from the work device. It is required to prevent problems associated with entering the shaft portion by contacting the minute gaps of the moving portion or the sliding portion.

As an example of a conventional structure for sealing so that foreign substances such as earth and sand do not enter, there is a structure that prevents intrusion of earth and sand by installing a pin seal and an O-ring as shown in FIG.

For example, the shaft pin 23 serving as the central axis is inserted and fixed in the through hole of the bracket 121 on both sides fixed to the working member 20 (bucket), and the shaft pin 23 between the brackets 121 is fixed.
A shaft support mechanism for rotatably supporting the cylindrical boss portion 53a at the tip of the link arm 53 is employed on the outer periphery of the link arm 53. The shaft pin 23 is inserted into the inner periphery of the bearing hole of the cylindrical boss portion 53 a via a cylindrical bush 57, and the grease nipple 2 at the end of the shaft pin 23 is inserted into the bush 57.
The grease is supplied from 3b through the grease passage 23a and lubricated.

In that case, an annular fixing member 121b is installed at the inner end of the bracket 121 facing the both side end surfaces of the cylindrical boss 53a, and the gap between the boss 53a and the bracket 121 is adjusted. Further, in order to prevent foreign matter from entering a minute gap formed between the cylindrical boss portion 53a and the fixing member 121b on both sides, the concave groove 1 is formed on the outer peripheral portion of the fixing member 121b.
25, and a seal structure in which an O-ring 126 is mounted in the concave groove 125 is employed. A pin seal 58 (dust seal) is provided at the end of the bearing hole on the inner periphery of the boss portion 53a.
Is employed, and a structure that prevents foreign matter such as earth and sand from entering the sliding gap between the outer periphery of the shaft pin 23 and the bush 57 is employed (see FIG. 3 described later).

As another conventional shaft seal structure, Japanese Patent Application Laid-Open No. H10-228707 discloses a size of a gap formed between brackets on both sides of the cylindrical boss portion in the shaft support mechanism similar to that shown in FIG. In order to adjust the thickness, a disc-shaped shim is interposed, and a concave groove is provided in the outer peripheral portion so that foreign matter such as earth and sand does not enter the shim portion, and the shaft portion in which the O-ring is similarly installed Seal structure is adopted. In addition, in order to seal the shaft support hole in the bracket and the outer periphery of the shaft pin, it has been proposed to provide a groove on the inner peripheral surface of the shaft support hole of the bracket and attach an O-ring.

Japanese Utility Model Publication No. 7-25049

By the way, in the conventional structure of the above example shown in FIG.
If the gap between the boss portion 53a of the link arm 53 and the cylindrical boss portion 53a becomes large due to wear or deformation, the work member 20 moves relative to the link arm 53 in the longitudinal direction of the shaft and becomes loose. 126 may escape from the concave groove 125 to the outside, and the sealing performance may deteriorate. And foreign substances, such as earth and sand, the clearance gap between the boss | hub part 53a and the fixing member 121b, and the boss | hub part 5
3b and the outer periphery of the shaft pin 23 may enter the bush 57 portion, and the swingability and lubricity may be impaired.

In the other conventional structure described in Patent Document 1, two O-rings are used and an O-ring groove must be additionally formed on the working member (bucket) side, which increases the manufacturing cost. Have a problem. Further, since the axial movement of the boss portion, that is, the backlash is adjusted by the shim, there is a problem that the man-hour for adjusting the shim is required, for example, it is necessary to prepare shims having different thicknesses.

The present invention has been made in view of the problems as described above. In the shaft support mechanism of the working member, the foreign matter such as earth and sand is prevented from entering the sliding gap, and the gap between the boss portion and the fixing member. An object of the present invention is to provide a shaft seal structure for a work machine that prevents backlash in the longitudinal direction of the shaft due to fluctuations of the shaft.

In order to achieve the above object, a shaft seal structure for a work machine according to the present invention has a work device in which a swinging or rotating work member (for example, the work member 20 in the embodiment) is pivotally connected by a shaft support mechanism. In work machines,
A shaft pin attached to the working member (for example, the shaft pin 23 in the embodiment), a boss portion pivotally supported with respect to the shaft pin (for example, the boss portion 53a in the embodiment), A fixing member (for example, the fixing member 21b in the embodiment) installed on the shaft pin on both sides of the boss portion via a predetermined gap (for example, the gap G1 in the embodiment) and the gap A shaft seal member (for example, the shaft seal member 26 in the embodiment) made of an elastic material attached to
The shaft sealing member includes a plate-like portion (for example, the plate-like portion 26a in the embodiment) having a center hole (for example, the center hole 26c in the embodiment), and an outer periphery of the center hole protruding from both surfaces of the plate-like portion. A protrusion (for example, the protrusion 26b in the embodiment) formed in a protrusion on the portion, and the plate-like portion and the protrusion are formed in the same elastic material in a solid integrated structure,
The diameter of the center hole of the shaft seal member is set to be a predetermined amount smaller than the outer diameter of the shaft pin inserted through the center hole. It is configured to press contact with the peripheral surface of the inserted shaft pin,
A dimension in the thickness direction of the shaft seal member at the protrusion is set to be a predetermined amount larger than a dimension of the gap between the end face of the boss part and the end face of the fixing member, and the top end of the protrusion is the boss part. The size of the gap is regulated while ensuring a sealing function by pressing against the end surface of the first member and the end surface of the fixing member.

In the above-described shaft seal structure, a bush (
For example, it is preferable that the bush 57) in the embodiment is mounted, and a pin seal (for example, the pin seal 58 in the embodiment) that is in sliding contact with the peripheral surface of the shaft pin is installed at the end of the bush.

In the above-described shaft portion seal structure, it is preferable that the lubricating oil is supplied to the inner peripheral portion of the boss portion by a grease passage (for example, the grease passage 23a in the embodiment) formed from the end portion of the shaft pin.

In the above-described shaft seal structure, the working member is a bucket, and the shaft pin is held in a retaining state and a rotation preventing state by a bracket (for example, the bracket 21 in the embodiment) fixed to the bucket. preferable.

In the shaft seal structure according to the present invention, the protrusion of the ridge is formed in the gap between the boss portion pivotally supported by the shaft pin attached to the working member and the fixing members installed on both sides thereof. A shaft seal member made of an elastic material having a portion is mounted. For this reason, foreign matter such as earth and sand enters into the shaft support portion of the boss portion from the gap with the work, and the top portion of the projection portion of the shaft seal member presses against the boss portions on both sides and the end surfaces of the fixing member to This can be prevented by sealing. In addition, the size of the gap can be regulated by the protruding portion of the shaft seal member being in pressure contact with the end surface of the boss portion and the end surface of the fixing member, and rattling due to the movement of the boss portion in the axial longitudinal direction accompanying the expansion of the gap. Can be prevented. Thus, without using an O-ring, it is possible to obtain both the effects of preventing entry of foreign matters such as earth and sand and preventing the backlash of the boss portion from increasing in the axial direction without using an O-ring.

In the shaft seal structure described above, the shaft sealing member and the protrusion and the plate portion are integrally formed of the same resilient material, further, the diameter of the central hole of the shaft sealing member, to the central bore predetermined amount than the outer diameter of the shaft pin to be inserted is smaller is set. When the center hole diameter of the shaft seal member is set in this way, when the shaft pin is inserted into the center hole, the plate-like portion has elasticity, so that the center hole diameter is widened and the inner peripheral surface is the shaft. It can be pressed against the peripheral surface of the pin, and the sealing performance of the peripheral surface of the shaft pin can be ensured to prevent foreign matters such as earth and sand from entering from the outside through the gap in the peripheral surface of the shaft pin.

Further, in the above-described shaft seal structure, a bush is mounted between the shaft pin and the inner periphery of the boss portion, and a pin seal that is in sliding contact with the peripheral surface of the shaft pin is installed at the end of the bush. Is preferred. Thus, when a bush and pin seal are installed on the boss,
The bushing improves sliding characteristics and durability, and the pin seal improves the sealability of the outer peripheral surface of the shaft pin, thereby further preventing foreign matter from entering the bush.

In the above-described shaft portion seal structure, it is preferable that lubricating oil is supplied to the inner peripheral portion of the boss portion by a grease passage formed from an end portion of the shaft pin. As described above, when the lubricating oil is supplied by forming the grease passage, the lubricating characteristics of the boss portion with respect to the shaft pin can be secured, and the supplied lubricating oil travels around the shaft pin and reaches the shaft seal member. In addition, the lubricity of the sliding contact portion between the shaft seal member and the boss portion can be obtained, the occurrence of wear can be suppressed, and the durability can be enhanced.

In the above-described shaft seal structure, it is preferable that the working member is a bucket, and the shaft pin is held in a state in which the shaft pin is prevented from being detached and prevented from being rotated by a bracket fixed to the bucket. Thus, when the shaft support mechanism is configured so that the shaft pin is fixed to the bucket and swings with respect to the boss portion, the shaft pin does not rotate with respect to the bucket as the bucket swings. Therefore, the swing support structure between the bucket and the shaft pin is unnecessary, and the required strength for attaching the support pin to the bucket can be easily secured.

It is a side view which shows the principal part structure of the working machine which has an example working apparatus to which this invention is applied. It is sectional drawing of the shaft support mechanism which has a shaft part seal structure in alignment with the AA cross section of FIG. It is the B section enlarged view in the axial part seal structure of FIG. It is sectional drawing of the shaft support mechanism which has an example of the conventional shaft part seal structure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a working device 10 of a power shovel as an example of a working machine in which a shaft support mechanism having a shaft seal structure to which the present invention is applied is installed.

The working device 10 includes a working member 20 (bucket) at a distal end, a working arm 30 that holds the working member 20 so as to be swingable, and a working boom 40 that holds the working arm 30 so as to be able to swing up and down. A first actuator 50 (hydraulic cylinder) that swings and drives the work member 20 and a second actuator 60 (hydraulic cylinder) that swings and drives the work arm 30 are provided.

FIG. 1 shows only the main part of the work device 10 (excavator mechanism), and the base end portion of the work boom 40 is swung to the upper part of a traveling carriage (vehicle body) that travels with left and right traveling mechanisms provided, for example. A work machine is installed so as to be connected to the front part of the swivel base provided so as to be operated by the operator cabin for riding the driver standing on the upper part of the swivel base. . The shaft portion seal structure of the present invention is applicable to various work machines.

The working device 10 in FIG. 1 will be specifically described. A plate-like bracket 21 that protrudes rearward and extends parallel to the left and right is fixed to the back of the working member 20 (see FIG. 2). This bracket 21
A shaft pin 22 serving as the center of swinging of the working member 20 is disposed on the distal end side of the working member 20, and the distal end portion of the working arm 30 is pivoted by the shaft pin 22. On the other end side of the bracket 21, the working member 20
A shaft pin 23 for swinging is installed, and the tip of the first link arm 53 is pivoted.

The other end of the first link arm 53 is connected to the first actuator 5 by a shaft pin 52.
While being pivotally connected to the distal end portion of the zero extension rod 51, the proximal end portion of the second link arm 54 is also pivotally connected to the distal end portion of the extension rod 51 of the first actuator 50 by the shaft pin 52. The distal end portion of the second link arm 54 is pivotally connected to the vicinity of the distal end portion of the work arm 30 by the shaft pin 33.

A parallelogram link mechanism is formed by the first link arm 53 and the second link arm 54, and the work member 20 (bucket) according to the expansion / contraction operation of the expansion / contraction rod 51 of the first actuator 50. Is configured to swing around the shaft pin 22 on the distal end side of the bracket 21.

A substantially triangular mounting bracket 31 is fixed to the base end portion of the working arm 30, and the base end portion of the first actuator 50 is pivotally connected to the front end portion side of the mounting bracket 31 by the shaft pin 32. The first actuator 50 is disposed substantially parallel to the outside of the first actuator 50. The work arm 30 is formed in a hollow prismatic shape by appropriately combining steel plates.

The base end of the work arm 30 is pivotally connected to the tip of the work boom 40 by a shaft pin 41 serving as a swing center, and the second actuator 60 extends and contracts on the base end side of the mounting bracket 31 of the work arm 30. The tip of the rod 61 is pivotally connected by a shaft pin 62. The work arm 30 is configured to swing around the shaft pin 41 on the distal end side of the work boom 40 in accordance with the expansion / contraction operation of the telescopic rod 61 of the second actuator 60.

Next, based on FIGS. 2 and 3, the first link arm 5 centering on the shaft pin 23 is used.
The shaft support mechanism of the cylindrical boss portion 53a at the distal end portion 3 and the bracket 21 of the work member 20 will be described.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and the tip cylindrical boss portion 53 a of the first link arm 53 and the bracket 21 fixed to the working member 20 (bucket) are swung by the shaft pin 23. A shaft support mechanism that is pivotably connected is shown, and the shaft seal structure of the present invention is installed in this shaft support mechanism. Further, FIG. 3 is an enlarged view of a portion B in FIG. 2 and shows details of the shaft seal portion.

The boss portion 53a formed in a cylindrical shape at the tip of the first link arm 53 is fitted with a cylindrical bush 57 in a bearing hole on both sides with a gap in the middle portion. A pin seal 58 (dust seal) is attached to each end.

On the other hand, a plate-like bracket 21 is fixed to the back surface portion of the working member 20 at a predetermined interval, and a shaft pin 23 serving as a rotation center axis is inserted and fixed in a through hole formed in the brackets 21 on both sides.

The shaft pin 23 is fixed on the outer surface of one bracket 21 by a ring-shaped locking member 21.
a is fixed, and bolts 24 are attached to the ends of the locking member 21a and the shaft pin 23 in the diametrical direction and fastened. The bolts 24 prevent the shaft pin 23 from coming off and prevent the bracket 21 from rotating.

Further, annular fixing members 21b having a predetermined thickness are fixed to the inner end surfaces of the brackets 21 on both sides, and the first links are respectively connected to shaft pins 23 between the fixing members 21b on both sides via shaft seal members 26 described later. The tip boss portion 53a of the arm 53 is held so as to be relatively rotatable. The lubricating structure is such that the grease passage 23 communicates between the central portion of one end of the shaft pin 23 and the bushes 57 on both sides.
a is formed, and lubricating oil (grease) is supplied from a grease nipple 23b installed at the end. Part of the lubricating oil reaches the portion of the outer shaft seal member 26 beyond the pin seal 58, and lubrication between the shaft seal member 26 (projecting portion 26b) and the side end surface of the boss portion 53a is also performed. To do.

As shown in FIG. 3, the pin seal 58 has its inner peripheral tip portion in sliding contact with the outer peripheral surface of the shaft pin 23, and the inner peripheral surface of the bush 57 inside the pin seal 58 and the shaft pin 2.
The sealing function is obtained so that foreign matter does not enter the sliding gap with the outer peripheral surface 3.

The shaft seal member 26 is formed in a disk shape by an elastic material having the same elastic characteristics as the conventional O-ring, and as shown in FIG. It has a protruding portion 26b protruding from the strip. The shaft pin 23 is inserted into the center hole 26c opened at the center of the plate-like portion 26a. The inner diameter of the center hole 26c in the free state is set to be a predetermined amount smaller than the outer diameter of the shaft pin 23. The center hole 26c is enlarged and deformed so that the inner peripheral surface of the center hole 26c is pressed against the peripheral surface of the shaft pin 23 into which the center hole 26c is inserted to obtain a sealing function.

Further, the height of the projection 26b of the shaft seal member 26, that is, the dimension in the thickness direction, is larger by a predetermined amount than the dimension of the gap G1 between the end surface of the fixing member 21b of the bracket 21 and the side end surface of the boss portion 53a. At the time of mounting, the projection 26b is compressed and deformed by the axial pressing force, and the top end of the projection 26b is pressed against the end surface of the fixing member 21b and the side end surface of the boss portion 53a by the elastic force accompanying the deformation. In addition, it has the same function as the shim so as to maintain the gap G1 while ensuring the sealing function.

Further, the shaft seal member 26 also seals foreign matters such as earth and sand that enter from the outside through the gap G2 between the inner peripheral surface of the fixing member 21b and the outer peripheral surface of the shaft pin 23.

The shaft seal member 26 also functions as a shim that adjusts the size of the gap G1 as described above, and the work member 20 and the boss portion 53a of the first link arm 53 are connected to the shaft pin 23.
The material (elastic modulus) of the shaft seal member 26 and the height of the protruding portion 26b are set so as not to move relative to a predetermined amount in the axial direction.

According to the above-described embodiment, the second actuator 60 is expanded and contracted to drive the operating arm 30 to swing, and the first actuator 50 is expanded and contracted in conjunction with this to swing the work member 20. By dynamically driving, work such as excavation is performed by the work member 20 (bucket).

At that time, foreign matter such as excavated earth and sand adheres to the shaft support mechanism by the shaft pin 23 between the boss portion 53a of the first link arm 53 and the bracket 21, and as shown by an arrow D in FIG. An attempt is made to enter the gap G1 between the end surface of the fixing member 21b and the side end surface of the boss portion 53a, but the projection 26b of the shaft seal member 26 is in pressure contact with the end surface of the fixing member 21b and the side end surface of the boss portion 53a. As a result, entry into the gap G1 inside the protrusion 26b is prevented, and the slidability can be achieved without being interposed in the sliding portion between the peripheral surface of the shaft pin 23 and the inner peripheral surface of the bush 57. It can be prevented from being inhibited. Further, the pin seal 5 installed at the end of the bush 57
8 also prevents foreign matter from entering the sliding contact portion between the bush 57 and the shaft pin 23.

The center hole 26c of the seal member 26 is connected to the shaft pin 23 against foreign matter such as earth and sand entering from the outside through the gap G2 between the inner peripheral surface of the fixing member 21b and the outer peripheral surface of the shaft pin 23. Can be prevented from intruding into the portion of the bush 57, and further the pin seal 58
Will also prevent intrusion.

As described above, according to the shaft seal structure of the present invention, intrusion of earth and sand or the like into the portion of the bush 57 that slides with the outer periphery of the shaft pin 23 is prevented, and the shaft seal member 26 has the gap G1. By adjusting the size, the movement of the working member 20 and the first link arm 53 in the axial direction can be restricted, and the gap G1 can be prevented from becoming larger than a predetermined amount.

In particular, since the conventional O-ring seal structure is not adopted, the O-ring escapes to the outside with use, and the sealing characteristics are not deteriorated. Performance can be maintained, no O-ring mounting groove is required, and both low-cost prevention of entry of foreign materials such as earth and sand and prevention of increased backlash in the axial direction of the boss portion 53a are expected. can do.

In addition, this invention is not specified to the structure of the said embodiment, The various deformation | transformation aspects are included. For example, in the above-described embodiment, an example of a bucket is shown as the work member 20, but it can be applied to a work member in other work machines, and can be applied to a shaft support mechanism for its swinging or turning operation. The same function can be obtained by installing a shaft seal member having an annular protrusion in the gap between the fixing member and the boss.

DESCRIPTION OF SYMBOLS 10 Work apparatus 20 Work member 21 Bracket 21a Locking member 21b Fixing member 23 Shaft pin 23a Grease passage 23b Grease nipple 24 Bolt 26 Shaft seal member 26a Plate-like part 26b Protrusion part 26c Center hole 30 Work arm 40 Work boom 50 1st Actuator 51 Telescopic rod 53 First link arm 53a Boss portion 54 Second link arm 57 Bush 58 Pin seal 60 Second actuator G1 Gap

Claims (4)

In a working machine having a working device in which a swinging or rotating working member is pivotally connected by a shaft support mechanism,
A shaft pin attached to the working member;
A boss portion pivotally supported with respect to the shaft pin;
A fixing member installed on the shaft pin on both sides of the boss portion via an end surface of the boss portion and a predetermined gap;
It consists of a shaft seal member made of an elastic material attached to the gap,
The shaft seal member includes a plate-like portion having a center hole, and protrusions that protrude from both sides of the plate-like portion and are formed on the outer peripheral portion of the center hole, and the plate-like portion and the protrusion The part is formed of the same elastic material in a solid monolithic structure ,
The diameter of the center hole of the shaft seal member is set to be a predetermined amount smaller than the outer diameter of the shaft pin inserted through the center hole. It is configured to press contact with the peripheral surface of the inserted shaft pin,
A dimension in the thickness direction of the shaft seal member at the protrusion is set to be a predetermined amount larger than a dimension of the gap between the end face of the boss part and the end face of the fixing member, and the top end of the protrusion is the boss part. A shaft seal structure for a working machine, wherein a size of the gap is regulated while ensuring a sealing function by pressing against an end surface of the fixing member and an end surface of the fixing member.   The work according to claim 1, wherein a bush is mounted between the shaft pin and an inner periphery of the boss portion, and a pin seal is provided at an end of the bush so as to be in sliding contact with the peripheral surface of the shaft pin. Machine shaft seal structure.   The shaft seal structure for a work machine according to claim 1 or 2, wherein lubricating oil is supplied to an inner peripheral portion of the boss portion by a grease passage formed from an end portion of the shaft pin.   The work machine according to any one of claims 1 to 3, wherein the working member is a bucket, and the shaft pin is held by a bracket fixed to the bucket in a state in which the shaft pin is prevented from being detached and turned. Shaft seal structure.

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