Work machine swiveling frame and assembly method for work machine swiveling frame

Patent metadata

Field	Value
Publication number	US-12240737-B2
Application number	US-202117906231-A
Country	US
Kind code	B2
Filing date	Mar 4, 2021
Priority date	Apr 3, 2020
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

A slewing frame of a work machine and a method of assembling a slewing frame of a work machine where the slewing frame is separable into at least two front and rear members, and an operation of connecting these two members can be easily performed. A slewing frame is separable into a front frame and a rear frame. When a pin fitting portion of a rear frame is fitted on a positioning pin of a front frame, and the rear frame is rotated downward, at a position where a front pin hole and a rear pin hole are aligned with each other, a contact portion of the rear connecting portion is brought into contact with a rotation preventing portion. As a result, a connecting pin can be easily inserted into the front pin hole and the rear pin hole.

First claim

The invention claimed is:

1. A slewing frame that is supported on a lower body of a work machine so as to be turnable about a turning center axis that extends in a vertical direction, the slewing frame comprising:
a front frame that forms a front side portion of the slewing frame, and is turnably supported by the lower body; and
a rear frame that forms a rear side portion of the slewing frame, and is detachably connected to the front frame,
wherein the front frame has a pair of left and right front connecting portions each of which includes a positioning pin that extends in a left-right direction, the pair of left and right front connecting portions being disposed on a rear end portion of the front frame spaced apart from each other in the left-right direction,
in the pair of left and right front connecting portions, a front side pin hole that allows a connecting pin that connects the front frame and the rear frame to each other to pass therethrough is formed in the left-right direction below the positioning pin respectively, a distance between the front side pin hole and the positioning pin being set to a predetermined reference distance as viewed in the left-right direction,
the rear frame has a pair of left and right rear connecting portions that are disposed spaced apart from each other in the left-right direction on a front end portion of the rear frame such that the pair of left and right rear connecting portions face the pair of left and right front connecting portions in the left-right direction,
the pair of left and right rear connecting portions each include an inner peripheral surface that defines an opening portion that allows the positioning pin to pass through the opening portion in a vertical direction, and a pin fitting portion that communicates with the opening portion above the opening portion and is configured to fit on an outer peripheral surface of the positioning pin such that rear frame is rotatable about the positioning pin,
a rear side pin hole that allows insertion of the connecting pin is formed along the left-right direction in a portion of each of the pair of left and right rear connecting portions below the pin fitting portion, a distance between the pin fitting portion and the rear side pin hole is set to the reference distance as viewed in the left-right direction,
the pair of left and right front connecting portions of the front frame each have a rotation preventing portion capable of preventing rotation of the rear frame in a downward direction about the positioning pin, and
the pair of left and right rear connecting portions of the rear frame each have a contact portion that is disposed on a plane that is orthogonal to the left-right direction and passes the rotation preventing portion, the contact portion being configured to be brought into contact with the rotation preventing portion such that further rotation of the rear frame is prevented at a position where the front side pin hole and the rear side pin hole are aligned with each other in the left-right direction along with the rotation of the rear frame, wherein
the positioning pin is disposed behind the front side pin hole such that a straight line passing through a center of the positioning pin and extending in the vertical direction does not intersect the front side pin hole, and the pin fitting portion is disposed behind the rear side pin hole such that a straight line passing through a center of the pin fitting portion and extending in the vertical direction does not intersect the rear side pin hole, as viewed in the left-right direction,
each of the pair of left and right rear connecting portions further has an inclined surface that is disposed below the pin fitting portion and above the rear side pin hole, and is brought into contact and guide the positioning pin, the inclined surface being frontwardly and upwardly inclined toward a rear side so as to be connected with the inner peripheral surface that defines the pin fitting portion in a posture of the rear frame where the pin fitting portion opens downward, and
in the rear frame, the contact portion is disposed behind and below the rear side pin hole, the inclined surface is disposed above the rear side pin hole, and the rear side pin hole is formed between the contact portion and the inclined surface.

2. The slewing frame of a work machine according to claim 1 , wherein
the contact portion is disposed behind the rear side pin hole and is disposed on a circumference having the reference distance as a radius about the pin fitting portion as viewed in a left-right direction, and
the rotation preventing portion is disposed behind the front side pin hole and is disposed on a circumference having the reference distance as a radius about the positioning pin as viewed in a left-right direction.

3. A slewing frame of a work machine according to claim 1 , wherein
the contact portion is disposed behind and below the rear side pin hole, the contact portion is a recessed portion having a radially outward protruding convex surface with respect to a center of the rear side pin hole as viewed in a left-right direction, and
the rotation preventing portion is disposed behind and below the front side pin hole, and is a protruding portion having a radially outwardly protruding curved surface with respect to a center of the front side pin hole as viewed in the left-right direction, the rotation preventing portion being brought into face contact with the contact portion along with the rotation of the rear frame in a lower direction about the positioning pin.

4. The slewing frame of a work machine according to claim 1 , wherein
each of the pair of left and right front connecting portions further has a pair of left and right front connecting plates arranged to face each other in the left-right direction and a front block that is disposed above and in front of the positioning pin, and connects upper ends of the pair of left and right front connecting plates in the left-right direction,
each of the pair of left and right rear connecting portions further has a rear connecting plate that is capable of entering between the pair of left and right front connecting plates, and a rear block that is disposed on an upper end of the rear connecting plate,
the rear block has a distal end portion that is disposed above and in front of the pin fitting portion and is brought into contact with an upper surface portion of the front block when the rear frame is connected to the front frame.

5. A method of assembling a slewing frame that is supported by a lower body of a work machine so as to be turnable about a turning center axis that extends in a vertical direction, the method comprising:
a preparing step of preparing a front frame that forms a front side portion of the slewing frame is turnably mounted on the lower body, and a rear frame that forms a rear side portion of the slewing frame and is detachably connected to the front frame;
a lifting step of lifting the rear frame by a predetermined lifting device such that a pair of left and right rear connecting portions disposed on a front end portion of the rear frame respectively face a pair of left and right front connecting portions disposed on a rear end portion of the front frame in a longitudinal direction;
a positioning pin fitting step of moving the rear frame in air by the lifting device, and fitting pin fitting portions that are formed in the pair of left and right rear connecting portions on positioning pins formed in the pair of left and right front connecting portions such that the positioning pins extend in a left-right direction respectively from above;
a pin hole aligning step of rotating the rear frame downwardly about the positioning pins, bringing a contact portion of the rear frame into contact with a rotation preventing porti

Assignees

• Kobelco Constr Mach Co Ltd

Inventors

• Motoyama Yuudai
• Koyahata Akira

Classifications

• B66C2700/0371

  on a turntable · CPC title

• B66C23/365 Primary

  dismantable into smaller units for transport purposes · CPC title