Neutral return mechanism

Abstract

The neutral return mechanism (26) includes: a link shaft (31) that is pushed and pulled in the axial direction (D3) in conjunction with the swing operation of the operation member (80); a housing member (32) that houses the link shaft (31) in a manner that the link shaft is movably supported in the axial direction and protrudes from one end side thereof; and a neutral return spring (33) that returns the link shaft (31) from a moved position (P5, P6) after the operation by the operation member (80) to an initial position (P4) before the operation, and that is housed in the housing member (32) in the axial direction (D3) of the link shaft (31), the housing member (32) having a supported portion (39) that is supported by a support member (53) between a spring housing portion (40) that houses the neutral return spring (33) and a protruding exit (48) from which the link shaft (31) protrudes.

Description

Technical Field

[0001] This invention relates to a neutral return mechanism that returns operating components such as levers and pedals to a neutral position. Background Technology

[0002] In the prior art, there is a known operating machine disclosed in Patent Document 1.

[0003] The work machine disclosed in Patent Document 1 is equipped with an operating component (bulldozer operating lever) that can swing from a neutral position in one direction and another and operate a control valve that provides hydraulic control to a hydraulic actuator.

[0004] The operating component operates a pilot valve, which in turn operates a control valve to hydraulically control the hydraulic actuator. A neutral return mechanism, which returns the operating component to the neutral position, is assembled to the pilot valve.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-22642 Summary of the Invention

[0008] (The problem that the invention aims to solve)

[0009] However, it is desirable to construct a neutral return mechanism that compactly returns the operating components of the hydraulic actuator to the neutral position.

[0010] The object of the present invention is to compactly construct a neutral return mechanism that can swing from a neutral position in one direction and in the opposite direction, i.e., another direction, and return the operating component of the control valve that hydraulically controls the hydraulic actuator to the neutral position.

[0011] (Technical solutions used to address the problem)

[0012] One aspect of the invention relates to a neutral return mechanism capable of oscillating from a neutral position in one direction and in the opposite direction (i.e., another direction) and returning an operating component of an operating control valve to the neutral position, wherein the control valve hydraulically controls a hydraulic actuator. The neutral return mechanism comprises: a linkage shaft that is pushed or pulled in the axial direction in conjunction with the oscillating operation of the operating component; a housing component that supports the linkage shaft in a manner that allows it to move along the axial direction and allows one end of the linkage shaft to protrude; and a neutral return spring that returns the linkage shaft from a moved position after operation by the operating component to an initial position before operation, the neutral return spring being housed within the housing component along the axial direction of the linkage shaft, the housing component having a supported portion supported by a bracket component between a spring housing portion housing the neutral return spring and a protrusion for the linkage shaft to protrude.

[0013] Furthermore, the linkage shaft has a connecting portion pivotally supported and connected to the linkage arm. The linkage arm and the swing operation of the operating component are linked together, with the linkage shaft protruding radially outward from the rotation shaft. The rotation shaft rotates about an axis parallel to the axis perpendicular to the axis of the linkage shaft. The supported portion has a bearing portion in the bracket component that is rotatably supported about an axis parallel to the axis of the rotation shaft.

[0014] Furthermore, the axial length of the linkage shaft within the supported portion is less than the length of the neutral return spring in the axial direction of the linkage shaft when the linkage shaft is in its initial position.

[0015] Furthermore, the spring receiving portion includes a first spring bearing member and a second spring bearing member, which are housed at a distance from each other in the axial direction of the linkage shaft. A neutral return spring composed of a helical spring is sandwiched between the first spring bearing member and the second spring bearing member. The linkage shaft has an end portion located on the opposite side of the first end portion of the linkage shaft, i.e., the other end portion. The first spring bearing member is restricted from moving in the protruding direction by the supported portion and moves integrally with the linkage shaft in the retraction direction, which is the direction in which the linkage shaft protrudes from the housing component. The second spring bearing member is restricted from moving in the retraction direction by a portion on the housing component side and moves integrally with the end portion in the protruding direction.

[0016] In addition, the linkage shaft has a stop mechanism that holds the linkage shaft in the post-operation position outside the range of the linkage shaft's travel distance from the moving position after operation by the operating component to the initial position before operation by the neutral return spring.

[0017] Furthermore, the stop mechanism has a stop ball, a pressing ball, and a force-applying component housed at the end of the other end of the linkage shaft. The stop ball is freely movable in the radial direction of the linkage shaft and protrudes radially outward from the end of the linkage shaft outside the range of the stroke, engaging with a locking recess provided in the spring housing to hold the linkage shaft in the position after operation. The pressing ball uses the force of the force-applying component to press the stop ball radially outward from the linkage shaft.

[0018] (Invention effect)

[0019] According to the above-mentioned neutral return mechanism, the neutral return spring, which is pushed and pulled in the axial direction in conjunction with the swing operation of the operating component, returns from the moving position to the initial position, is housed in the housing component along the axial direction of the linkage shaft. Furthermore, a supported part supported by the bracket component is provided in the housing component between the spring housing part and the protrusion of the linkage shaft, thereby enabling the neutral return mechanism to be compactly formed. Attached Figure Description

[0020] Figure 1 This is a side sectional view of the neutral return mechanism according to the first embodiment.

[0021] Figure 2 This is a side view showing the installation state of the neutral return mechanism according to the first embodiment.

[0022] Figure 3 This is a front view showing the installation state of the neutral return mechanism according to the first embodiment.

[0023] Figure 4 This is a perspective view showing the installation state of the neutral return mechanism according to the first embodiment.

[0024] Figure 5 This is a side sectional view of the neutral return mechanism according to the second embodiment.

[0025] Figure 6 This is a side view of the machine.

[0026] Figure 7 It is a 3D view of the driver's compartment. Detailed Implementation

[0027] An embodiment of the present invention will now be described with reference to the accompanying drawings.

[0028] Figures 1 to 4 This represents the first implementation of the neutral return mechanism 26. Figure 1 This is a side sectional view of the neutral return mechanism 26. Figure 2 This is a side view showing the installation state of the neutral return mechanism 26. Figure 3 This is the main view showing the installation status of the neutral return mechanism 26. Figure 4 This is a perspective view showing the state in which the neutral return mechanism 26 is installed on the operating component.

[0029] The neutral return mechanism 26 is a mechanism that enables the swing operation component 80 to return from the operation position to the neutral position P1.

[0030] like Figure 4 As shown, in this embodiment, the operating component 80 is composed of an operating lever. Alternatively, the operating component 80 may also be a pedal. The operating lever 80 has a handle 80A for the operator to grip and an operating lever shaft 80B mounted on the upper part of the handle 80A. At the lower end of the operating lever shaft 80B, one end of a rotating shaft 27 is fixed, which can rotate about an axis (rotation axis) X2 extending in a direction perpendicular to the axis X5 of the operating lever shaft 80B.

[0031] like Figure 2 As shown, the rotating shaft 27 is mounted on the wall portion 54 where the neutral return mechanism 26 is mounted via a shaft mounting member (not shown), and is supported by the shaft mounting member in a manner that allows it to rotate about the rotating axis X2. The linkage arm 29 is fixed to the rotating shaft 27. The linkage arm 29 protrudes radially outward from the rotating shaft 27.

[0032] like Figure 2 As shown by the double-dotted line, the operating lever 80 can swing to a first operating position P2 and a second operating position P3. The first operating position is the position where the operating lever axis 80B extends in the vertical direction, i.e., the neutral position P1, and the position where it swings around the rotation axis X2 in one direction D1. The second operating position is the position where it swings around the neutral position P1 in the opposite direction of the rotation axis X2, i.e., the other direction D2.

[0033] like Figure 4As shown, the operating direction (swing direction) and operating amount (swing amount) of the operating lever 80 are detected by the angle sensor S1. The angle sensor S1 is, for example, a potentiometer. The angle sensor S1 is connected to the operating device U1. The operating device U1 can obtain the detection information (operating direction and operating amount of the operating lever 80) from the angle sensor S1. Therefore, the detection signal detected by the angle sensor S1 is sent to the operating device U1, and the operating device U1 electrically controls the control valve (hydraulic solenoid valve) V1 according to the detection signal from the angle sensor S1. This control valve hydraulically controls the hydraulic cylinder C1, which is operated by the operating lever 80. That is, when the operating lever 80 is operated, the operating device U1 controls the current supplied to the control valve V1 (or sends a signal to the control valve V1), and the hydraulic cylinder C1 operates. Therefore, the operating lever 80 is the operating component for operating the control valve V1 that hydraulically controls the hydraulic cylinder (hydraulic actuator) C1, and is used for electrically controlling the control valve V1 that hydraulically controls the hydraulic cylinder (hydraulic actuator) C1.

[0034] like Figure 1 and Figure 2 As shown, the neutral return mechanism 26 includes a linkage shaft 31, a housing component 32, and a neutral return spring 33. The linkage shaft 31 has a two-strand connecting portion 34 at one end (the axial direction end side) 35A in the axial direction D3. The connecting portion 34 is pivotally connected to the linkage arm 29 via a connecting pin 36. Therefore, when the rotating shaft 27 is rotated by the swinging operation of the operating lever 80, the linkage arm 29 swings about the rotation axis X2, causing the linkage shaft 31 to be pushed and pulled in the axial direction. In other words, the linkage shaft 31 is pushed and pulled in the axial direction D3 in conjunction with the swinging operation of the operating lever (operating component) 80.

[0035] like Figure 1 As shown, a small-diameter portion 31B with a diameter smaller than the outer diameter of the shaft body 31A is formed on the other end side (the other end side of the axis direction) 35B of the linkage shaft 31 in the axial direction (also referred to as the linkage shaft axis direction) D3. Furthermore, a threaded hole 37 is formed on the other end side 35B of the linkage shaft 31 in the axial direction, extending from the other end side 35B to the other end side 35A (from the small-diameter portion 31B to the shaft body 31A) along the linkage shaft axis direction D3. A threaded hole is a hole with internal threads cut on its inner surface. Additionally, the linkage shaft 31 has an end portion 38 on the other end side 35B in the axial direction. The end portion 38 is formed by a bolt and screwed into the threaded hole 37 to be mounted to the small-diameter portion 31B and the shaft body 31A. The rotation axis X2 is parallel to a direction perpendicular to the axis X3 of the linkage shaft 31.

[0036] like Figure 1As shown, the housing component 32 supports the linkage shaft 31 in a manner movable in the axial direction D3, and houses the linkage shaft 31 such that one end of the linkage shaft 31 (one end in the axial direction 35A) protrudes. In other words, the housing component 32 supports the linkage shaft 31 in a manner movable in the direction in which the linkage shaft 31 protrudes from the housing component 32, i.e., the protrusion direction D4, and in the opposite direction of the protrusion direction D4, i.e., the retraction direction D5.

[0037] The housing component 32 has a supported portion 39 at one end 35A in the axial direction of the linkage shaft 31 and a spring receiving portion 40 at the other end 35B in the axial direction of the linkage shaft 31. The supported portion 39 and the spring receiving portion 40 are formed separately.

[0038] The supported portion 39 has a through hole 46 formed in the axial direction D3 of the linkage shaft. The linkage shaft 31, with its shaft body 31A inserted through the through hole 46, is supported on the supported portion 39 in a movable manner in the axial direction D3 by a bushing 47 fitted into the inner surface of the through hole 46. One end of the through hole 46 (one end 35A in the axial direction) becomes a protrusion 48 of the linkage shaft 31. Therefore, the supported portion 39 is disposed between the spring receiving portion 40 and the protrusion 48. A dustproof seal 49 is provided on the protrusion 48 side of the bushing 47.

[0039] like Figure 1 As shown, a bearing portion 50 and a connecting portion 51 are formed in the supported portion 39.

[0040] like Figure 3 As shown, the bearing portion 50 includes a first bearing portion 50A and a second bearing portion 50B that integrally extend from the body portion 39A, which is supported by the support portion 39, at the location where the through hole 46 is formed. The first bearing portion 50A extends in a direction D6 perpendicular to the axis X3 of the linkage shaft 31. The first bearing portion 50A has a first support hole 52A formed from its extension end toward the body portion 39A. The second bearing portion 50B extends in a direction D7, which is perpendicular to the axis X3 of the linkage shaft 31 and opposite to the direction D6 in which the first bearing portion 50A extends. The second bearing portion 50B has a second support hole 52B formed from its extension end toward the body portion 39A. The first support hole 52A and the second support hole 52B have concentric axes in a direction perpendicular to the axis X3 of the linkage shaft 31.

[0041] like Figure 2 and Figure 3 As shown, the supported portion 39 is pivotally supported on the bracket member 53. The bracket member 53 has: an upper wall 53a; a first side wall 53b extending downward from one side of the upper wall 53a; and a second side wall 53c extending downward from the other side of the upper wall 53a.

[0042] like Figure 2As shown, the upper wall 53a is positioned above the axial end 35A of the supported portion 39 and the linkage shaft 31, and is mounted to the protrusion 55 protruding downward from the wall portion 54 located above the bracket member 53 by bolts 56. A first side wall 53b extends from the upper wall 53a toward the first bearing portion 50A and has a first pivot support wall 53d located on the side of the first bearing portion 50A. The first bearing portion 50A is pivotally supported on the first pivot support wall 53d by a first pivot support pin 57A, which passes through the first pivot support wall 53d and is inserted through a first support hole 52A. A second side wall 53c extends from the upper wall 53a toward the second bearing portion 50B and has a second pivot support wall 53e located on the side of the second bearing portion 50B. The second bearing portion 50B is pivotally supported on the second pivot support wall 53e by the second pivot support pin 57B, which passes through the second pivot support wall 53e and is inserted through the second support hole 52B.

[0043] like Figure 2 As shown, the first pivot support pin 57A and the second pivot support pin 57B have an axis X4 parallel to the rotation axis X2. That is, the support portion 39 is supported on the bracket member 53 in a manner that allows rotation about an axis parallel to the axis of rotation 27 (rotation axis X2). Figure 3 As shown, the first pivot support pin 57A and the second pivot support pin 57B are prevented from detaching by the anti-detachment component 58.

[0044] like Figure 3 As shown, a pair of connecting portions 51 are provided. One connecting portion 51 extends in a direction perpendicular to the axis of the linkage shaft 31. The other connecting portion 51 extends in the opposite direction to the direction in which the first connecting portion 51 extends, perpendicular to the axis X3 of the linkage shaft 31. Figure 1 As shown, threaded holes 51a are formed in each joint 51.

[0045] like Figure 1 As shown, the spring receiving part 40 has a cylindrical receiving hole 59 concentric with the axis X3 of the linkage shaft 31. The receiving hole 59 is formed as a bottomed cylindrical shape with one end 35A open in the axial direction of the linkage shaft 31 and the other end 35B closed in the axial direction. The receiving hole 59 communicates with the through hole 46 of the supported part 39, and the other end of the linkage shaft 31 in the axial direction is inserted into the receiving hole 59.

[0046] The spring receiving portion 40 has a pair of connecting portions 60 corresponding to the connecting portion 51 of the supported portion 39. A threaded hole 60a is formed through the connecting portion 60. The connecting portions 51 and 60 are threadedly connected by screwing a bolt 61 into the threaded holes 51a and 60a, thereby connecting the supported portion 39 and the spring receiving portion 40.

[0047] The neutral return spring 33 is housed in the receiving hole 59 (within the housing component 32). The neutral return spring 33 is formed of a compression coil spring and is concentrically housed in the receiving hole 59. That is, the neutral return spring 33 is housed in the housing component 32 along the axis D3 of the linkage shaft.

[0048] The receiving hole 59 houses a first spring bearing member 62 and a second spring bearing member 63 that bear the load of the neutral return spring 33. The first spring bearing member 62 and the second spring bearing member 63 are housed in the spring receiving part 40 at a distance from each other in the axial direction D3 of the linkage shaft. The neutral return spring 33 is located between the first spring bearing member 62 and the second spring bearing member 63.

[0049] The first spring bearing member 62 has: a cylindrical portion 62a disposed on the outer periphery of the shaft body 31A of the linkage shaft 31; a first portion 62b extending radially outward from one end of the cylindrical portion 62a and abutting against the supported portion 39; and a second portion 62c extending radially inward from the other end of the cylindrical portion 62a and engaging with the stepped portion 64 between the shaft body 31A and the small-diameter portion 31B. Therefore, the first spring bearing member 62 is restricted from moving in the protruding direction D4 by the supported portion 39, and moves integrally with the linkage shaft 31 in the retraction direction D5.

[0050] The second spring bearing member 63 has: a cylindrical portion 63a disposed on the outer side of the head 38a of the end portion 38; a first portion 63b extending radially inward from one end of the cylindrical portion 63a and engaging with the flange portion 38b of the end portion 38; and a second portion 63c extending radially outward from the other end of the cylindrical portion 63a and abutting against the spring receiving portion 40. Therefore, the movement of the second spring bearing member 63 in the retraction direction D5 is restricted by the portion (spring receiving portion 40) on the housing member 32 side, and it moves integrally with the end portion 38 (linkage shaft 31) in the protrusion direction D4.

[0051] like Figure 1 and Figure 2 As shown, in the neutral return mechanism 26 described above, when the operating lever 80 is in the neutral position P1, the linkage shaft 31 is in the position before being operated, i.e., the initial position (neutral position of the linkage shaft 31) P4. In this initial position P4, the linkage shaft 31 is configured such that the axis X3 extends in the horizontal direction.

[0052] When the operating lever 80 is moved from the neutral position P1 to the first operating position P2, the linkage shaft 31 moves from the initial position P4 to the position operated by the operating lever 80, i.e., the first moving position (moving position) P5. When the linkage shaft 31 moves to the first moving position P5, the second spring bearing member 63 and the end 38 (linkage shaft 31) move together in the protruding direction D4 to compress the neutral return spring 33.

[0053] Furthermore, when the operating lever 80 is moved from the neutral position P1 to the second operating position P3, the linkage shaft 31 moves from the initial position P4 to the position after the operation of the operating lever 80, namely the second moving position (moving position) P6. When the linkage shaft 31 moves to the second moving position P6, the first spring bearing member 62 and the step portion 64 (linkage shaft 31) move together in the retraction direction D5 to compress the neutral return spring 33.

[0054] The operating load is applied to the operating lever 80 by compression of the neutral return spring 33. Furthermore, the operating load of the operating lever 80 can be changed by using (replacing) neutral return springs 33 with different loads.

[0055] When the operating force of the operating lever 80 is released or the operating lever 80 is returned to the neutral position P1, the linkage shaft 31 returns from the moving position (first moving position P5 or second moving position P6) to the initial position P4 through the force of the neutral return spring 33.

[0056] Furthermore, the travel H1 between the initial position P4 and the first moving position P5 and the travel H2 between the initial position P4 and the second moving position P6 are, for example, set to be approximately the same as the interval H3 between the second part 62c and the first part 63b when the linkage shaft 31 is in the initial position P4.

[0057] In the neutral return mechanism 26 constructed as described above, such as Figure 1 As shown, the axial length L1 of the linkage shaft 31 within the supported portion 39 is formed to be smaller than the length L2 of the neutral return spring 33 in the linkage shaft axis direction D3 when the linkage shaft 31 is in the initial position P4, so that the neutral return mechanism 26 is formed compactly. Furthermore, the length L3 of the supported portion 39 in the linkage shaft axis direction D3 is formed to be smaller than the length L4 of the spring housing portion 40 in the linkage shaft axis direction D3.

[0058] Furthermore, for example, in order to pivotally support the housing component 32 to the wall portion 54 side, a retaining member is fixed to the other end 35B of the linkage shaft 31 in the spring receiving portion 40 in the axial direction, and this retaining member is pivotally supported on the bracket component mounted on the wall portion 54. This configuration results in a larger neutralization return mechanism 26 in the linkage shaft center direction D3. In contrast, in this embodiment, a supported portion 39 is provided between the spring receiving portion 40 and the protrusion 48, pivotally supported on the bracket component 53 mounted on the wall portion 54, thus allowing for a compact neutralization return mechanism 26.

[0059] Furthermore, in the above embodiment, the supported portion 39 is pivotally supported on the bracket member 53 (supported so as to be rotatable about the axis X4), but this is not limited to this. The supported portion 39 may also be fixedly supported on the bracket member 53 (supported so as not to be rotatable). In this case, although there is no limitation, for example, the pin insertion hole formed in the linkage arm 29 for the insertion of the connecting pin 36 may be formed as an elongated hole so that the linkage shaft 31 may move linearly by the movement of the linkage arm 29 about the rotation axis X2.

[0060] Figure 5 This represents the second implementation of the neutral return mechanism 26.

[0061] In this second embodiment, the end portion 38 and the small diameter portion 31B are integrally formed, and the small diameter portion 31B is separately formed from the shaft body 31A. The threaded shaft portion 65 integrally formed in the small diameter portion 31B is screwed into the threaded hole 66 formed in the shaft body 31A, so that the small diameter portion 31B and the end portion 38 are mounted on the shaft body 31A.

[0062] The end portion 38 is formed as a cylinder with an outer diameter larger than that of the minor diameter portion 31B, and the outer diameter is formed to be approximately the same as that of the shaft body 31A. The first portion 63B of the second spring bearing member 63 engages with the step portion 67 between the minor diameter portion 31B and the end portion 38.

[0063] A receiving chamber 68 is formed at end 38. The receiving chamber 68 is formed by passing through a hole extending in the axial direction D3 from one end side 35B to one end side 35A in the axial direction of the linkage shaft 31. The receiving chamber 68 includes a first receiving chamber 68A at one end side 35A in the axial direction of the linkage shaft 31 and a second receiving chamber 68B at the other end side 35B in the axial direction of the linkage shaft 31. The first receiving chamber 68A is formed by a hole with a diameter smaller than that of the second receiving chamber 68B.

[0064] Furthermore, the end portion 38 has a through portion 69 formed radially through the inner surface of the second receiving chamber 68B and the outer surface of the end portion 38.

[0065] A stop mechanism 70 is housed in the receiving chamber 68 (end 38). The stop mechanism 70 holds the linkage shaft 31 in the operating position outside the range of the automatic return of the linkage shaft 31 from the moving position (first moving position P5, second moving position P6) to the initial position P4 by the neutral return spring 33, i.e., the range of the travel H1, H2 of the linkage shaft 31. The stop mechanism 70 has a stop ball 71, a pressing ball 72, and a force-applying component 73.

[0066] The stop ball 71 is housed within the second receiving chamber 68B. Specifically, the stop ball 71 is positioned corresponding to the through portion 69 and is freely movable within the through portion 69 in the radial direction of the end portion 38 (linkage shaft 31). In the second embodiment, a plurality of (four) through portions 69 are formed at equal intervals in the circumferential direction of the end portion 38. A plurality of (four) stop balls 71 are provided corresponding to the four through portions 69.

[0067] The press ball 72 is positioned between the stop ball 71 in the second containment chamber 68B and the first containment chamber 68A. The press ball 72 is sized to press all four stop balls 71.

[0068] The force-applying component 73 is formed by a coil spring and housed within the first receiving chamber 68A to apply force to the pressing ball 72. The force of the force-applying component 73 acts in the direction in which the pressing ball 72 presses the stop ball 71. That is, the pressing ball 72 uses the force of the force-applying component 73 to press the stop ball 71 radially outward toward the linkage shaft 31.

[0069] In the second embodiment, the spring receiving portion 40 includes a receiving portion body 40A and a sleeve 40B housed within the receiving portion body 40A. The receiving portion body 40A has an opening 74 at its opposite end 35B in the axial direction of the linkage shaft 31. The sleeve 40B is inserted into the receiving portion body 40A through the opening 74 and is prevented from disengaging by a washer 75 and an anti-disengagement member (clamp) 79. The second portion 63c of the second spring bearing member 63 abuts against the sleeve 40B (the portion on the housing member 32 side), thereby restricting its movement in the retraction direction D5.

[0070] On the inner circumference of the sleeve 40B, a tapered portion 88, a positioning protrusion 89, and an engaging recess 90 are provided, which are formed sequentially from one end 35B to one end 35A in the axial direction of the linkage shaft 31. The tapered portion 88, the positioning protrusion 89, and the engaging recess 90 are formed from the middle part in the axial direction of the sleeve 40B towards the vicinity of one end 35A of the linkage shaft 31.

[0071] The tapered portion 88 is formed into a tapered shape that gradually expands in diameter as it moves from the other end 35B in the axial direction of the linkage shaft 31 toward one end 35A (positioning protrusion 89).

[0072] The positioning protrusion 89 protrudes into the inner circumferential side of the sleeve 40B and is formed as a convex strip formed in the circumferential direction of the sleeve 40B.

[0073] The engaging recess 90 is formed on the inner circumference of the sleeve 40B by a circumferential groove formed in the circumferential direction.

[0074] In this second embodiment, such as Figure 5As shown, when the linkage shaft 31 is in the initial position P4, the stop ball 71 is located on the other end 35B of the linkage shaft 31 in the axial direction. When the operating lever 80 is operated from the neutral position P1 to the first operating position P2 to move the linkage shaft 31 to the first moving position P5, the stop ball 71 moves radially outward on the linkage shaft 31 while moving from the small diameter side to the large diameter side of the tapered portion 88, and abuts against the positioning protrusion 89.

[0075] When the operating lever 80 is swung further in one direction D1 from the position where the stop ball 71 abuts against the positioning protrusion 89 (when the linkage shaft 31 is in the first moving position P5), the stop ball 71 passes over the positioning protrusion 89 and engages with the engaging recess 90, and the linkage shaft 31 moves to the stop position P7. When the stop ball 71 engages with the engaging recess 90, the linkage shaft 31 will not return to the initial position P4 under the force of the neutral return spring 33, but will be held in the stop position P7. That is, the stop ball 71 protrudes radially outward from the end 38 towards the linkage shaft 31 outside the range of automatic return by the neutral return spring 33, i.e., the range of strokes H1 and H2, and engages with the engaging recess 90 provided in the spring receiving part 40 to hold the linkage shaft 31 in the operating position (stop position P7).

[0076] In this second embodiment, the distance H5 between the second part 62c of the first spring bearing member 62 and the first part 63b of the second spring bearing member 63 when the linkage shaft 31 is in the initial position P4 is set to be approximately the same as the travel H4 between the initial position P4 and the stop position P7.

[0077] On the other hand, when the operating lever 80 is operated to the second operating position P3 and the linkage shaft 31 is moved to the second moving position P6, the stop ball 71 moves the cylindrical part of the inner circumferential surface of the sleeve 40B to the other end 35B in the axial direction of the linkage shaft 31.

[0078] The other components of the second embodiment are the same as those of the first embodiment described above, so the description is omitted.

[0079] Figure 6 and 7 This indicates that the work machine 1 uses a neutral return mechanism 26. Figure 6 This is a top view showing the overall structure of the work machine 1. Figure 7 This is a perspective view of the driver's cab of the work machine 1. In this embodiment, a rotating work machine, i.e., an excavator, is illustrated as the work machine 1.

[0080] like Figure 6As shown, the work machine 1 includes a body (rotating platform) 2, a traveling device 3, and a working device 4. The driver's cab 5 is mounted on the body 2. Inside the driver's cab 5, there is a driver's seat 6 for the driver (operator).

[0081] In this embodiment, the driver, who sits in the driver's seat 6 of the machine 1, faces forward ( Figure 6 The direction of arrow A1 in the image is set to forward, and the driver's facing direction is set to the rear. Figure 6 The direction of arrow A2 in the image is set to backward. Figure 6 Arrow K1 is set to the forward / backward direction, positioning the driver's left side ( Figure 6 The front side is set to the left, and the driver's right side is set to the right. Figure 6 The depth side of the fuselage will be described as the right side. The direction perpendicular to the front-rear direction K1, i.e., the horizontal direction, will be described as the width direction of the fuselage (the width direction of fuselage 2).

[0082] like Figure 6 As shown, the traveling device 3 includes: a traveling frame 3A; a first traveling device 3L disposed on the left side of the traveling frame 3A; and a second traveling device 3R disposed on the right side of the traveling frame 3A. The first traveling device 3L is driven by a first traveling motor M1, and the second traveling device 3R is driven by a second traveling motor M2. The first traveling motor M1 and the second traveling motor M2 are composed of hydraulic motors (hydraulic actuators).

[0083] like Figure 6 As shown, a bulldozing device 7 is mounted at the front of the traveling unit 3. The bulldozing device 7 has a bulldozing arm 7A that is pivotally supported at the rear by the traveling frame 3A so as to be able to swing in the vertical direction, and a bulldozing blade 7B provided at the front end of the bulldozing arm 7A. The bulldozing device 7 can be raised and lowered (by extending and retracting the bulldozing cylinder (hydraulic actuator)) to raise and lower the bulldozing blade 7B.

[0084] like Figure 6 As shown, the body 2 is supported on the running frame 3A by a rotating bearing 8 in a manner that allows it to rotate about a rotation axis X1. A support bracket 20 is provided at the front of the body 2, and a swing bracket 21 is supported on this support bracket in a manner that allows it to rotate about a vertical axis (an axis extending in the vertical direction).

[0085] like Figure 6As shown, the working device 4 includes a boom 22, a stick 23, and a bucket (working tool) 24. The base of the boom 22 is pivotally connected to the upper part of the swing bracket 21 in a manner that allows it to rotate about a horizontal axis (an axis extending in the width direction of the machine body). The stick 23 is pivotally connected to the front end of the boom 22 in a manner that allows it to rotate about a horizontal axis. The bucket 24 is provided on the front end of the stick 23 in a manner that allows it to perform pushing and tipping actions. The pushing action is an action that causes the bucket 24 to swing in a direction close to the boom 22, for example, in the case of scooping up soil or sand. Furthermore, the tipping action is an action that causes the bucket 24 to swing in a direction away from the boom 22, for example, in the case of causing the scooped soil or sand to fall (discharge).

[0086] The work machine 1 can be equipped with other working tools (hydraulic attachments) driven by hydraulic actuators in place of the bucket 24, or in addition to the bucket, other working tools (hydraulic attachments) driven by hydraulic actuators can be installed. Examples of other working tools include hydraulic crushers, hydraulic breakers, angled brooms, burrs, pallet forks, sweepers, lawn mowers, snow blowers, etc.

[0087] The swing bracket 21 can swing by extending and retracting the swing cylinder C2 mounted on the machine body 2. The boom 22 can swing by extending and retracting the boom cylinder C3. The stick 23 can perform pushing and tipping actions by extending and retracting the stick cylinder C4. The swing cylinder C2, boom cylinder C3, stick cylinder C4, and bucket cylinder C5 are hydraulic cylinders (hydraulic actuators).

[0088] like Figure 6 As shown, a control device 41 is installed inside the cab 5. The control device 41 is located in front of the driver's seat 6. The driver's seat 6 and the control device 41 constitute the driving unit 42 of the driving work machine 1 (control body 2, travel device 3, work device 4, swing support 21, etc.).

[0089] like Figure 7 As shown, the driver's seat 6 is supported on the floor portion 5B that forms the bottom of the cab 5 by means of a seat platform 76, etc. A suspension device 77 is provided on the seat platform 76, and the driver's seat 6 is mounted on the suspension device 77 in a manner that allows for adjustment of its fore-and-aft position via a slide rail 78.

[0090] like Figure 7 As shown, the control device 41 includes a control panel 81, control components 82, a monitor 84, a driving pedal 85, and a control lever 80.

[0091] The control panel 81 is located in front of the pilot's seat 6 on the fuselage 2, and has a base 86 erected on the floor 5B (fuselage 2) and a control panel body 87 disposed above the base 86.

[0092] The control component 82 is a component for the operator to grip and operate, and it is mounted on the control panel body 87 (control panel 81). The control component 82 includes a first control handle 82L and a second control handle 82R arranged side by side in the width direction of the machine body. The first control handle 82L and the second control handle 82R can, for example, perform the rotation operation of the machine body 2, the swing operation of the boom 22, the swing operation of the stick 23, and the swing operation of the bucket 24.

[0093] like Figure 7 As shown, the control panel body 87 has armrests 93 arranged on the left and right sides of the control panel body 87. The left armrest 93, namely the first armrest 93L, has an armrest base 93L1 and an armrest body 93L2 pivotally supported at the rear of the armrest base 93L1. The right armrest 93, namely the second armrest 93, has an armrest base 93R1 and an armrest body 93R2 integrally formed with the armrest base 93R1. The armrest bodies 93L2 and 93R2 have elbow rests 93A at their rear for placing the driver's elbow.

[0094] The operating lever 80 is the bulldozing operating lever 80 for manipulating the bulldozing device 7. The bulldozing operating lever 80 can swing forward (in one direction D1) and backward (in another direction D2) from the neutral position P1. The neutral return mechanism 26 of the first and second embodiments described above is used to return the bulldozing operating lever 80 to the neutral position P1.

[0095] The second handrail 93R is hollow, and the neutral return mechanism 26 and the rotating shaft 27 are housed inside the handrail base 93R1 of the second handrail 93R. The wall 54 on which the neutral return mechanism 26 and the rotating shaft 27 are installed is the upper wall of the second handrail 93R.

[0096] Furthermore, the neutral return mechanism 26 can be used to return the travel pedal 85 to the neutral position. Additionally, the neutral return mechanism 26 can be used to return the swing pedal of the swing operation swing bracket 21 to the neutral position. Furthermore, the neutral return mechanism 26 can be used to return the AUX pedal, which is used to operate hydraulic attachments installed in place of or in addition to the bucket 24, to the neutral position. It can also be used to return other operating levers and pedals to the neutral position.

[0097] In the neutral return mechanism 26 of the second embodiment, the control valve for bulldozing employs a mechanism that provides a floating position for lowering the bulldozer blade 7B by its own weight (allowing free extension and retraction of the hydraulic cylinder that moves the bulldozer blade arm 7A up and down). In the neutral return mechanism 26 of the second embodiment, the control valve for bulldozing is switched to the floating position by moving the linkage shaft 31 to the stop position P7. That is, the control valve for bulldozing is kept in the floating position by holding the linkage shaft 31 in the stop position P7.

[0098] The neutral return mechanism 26 of this embodiment is a neutral return mechanism 26 that can swing from the neutral position P1 in one direction D1 and in the opposite direction of direction D1, namely another direction D2, and return the operating component 80 of the operating control valve V1 to the neutral position P1. The control valve V1 hydraulically controls the hydraulic actuator C1. The neutral return mechanism 26 includes: a linkage shaft 31, which is pushed and pulled in the axial direction D3 in conjunction with the swinging operation of the operating component 80; and a housing component 32 that houses the linkage shaft 31 to allow the linkage shaft 31 to move in the axial direction D3. The linkage shaft 31 is supported in a manner that allows one end of the linkage shaft 31 to protrude; and a neutral return spring 33 that returns the linkage shaft 31 from the moving position (first moving position P5, second moving position P6) after being operated by the operating member 80 to the initial position P4 before operation, and the neutral return spring is housed in the housing member 32 along the axial direction D3 of the linkage shaft 31, the housing member 32 having a supported portion 39, which is supported by a bracket member 53 between the spring housing portion 40 that houses the neutral return spring 33 and the protrusion 48 protruding from the linkage shaft 31.

[0099] According to this configuration, the neutral return spring 33, which pushes and pulls the linkage shaft 31 in the axial direction D3 in conjunction with the swing operation of the operating member 80, returns from the moving position P5, P6 to the initial position P4, is housed in the housing member 32 along the axial direction of the linkage shaft 31. Furthermore, a supported part 39, supported by the bracket member 53, is provided in the housing member 32 between the spring housing part 40 and the protrusion 48 protruding from the linkage shaft 31, thereby enabling the neutral return mechanism 26 to be compactly formed.

[0100] Furthermore, the linkage shaft 31 has a connecting portion 34 that is pivotally supported and connected to the linkage arm 29. The linkage arm 29, in conjunction with the swing operation of the operating component 80, protrudes radially outward from the rotation shaft 27, which rotates about an axis X2 parallel to the axis X3 of the linkage shaft 31. The supported portion 39 is supported in the bracket component 53 by a bearing portion 50 that is rotatable about an axis X4 parallel to the axis of the rotation shaft 27.

[0101] According to this structure, the neutral return mechanism 26 can follow the movement of the linkage arm 29 around the rotation axis 27.

[0102] Furthermore, the axial length L1 of the linkage shaft 31 within the supported portion 39 is less than the length L2 of the neutral return spring 33 in the axial direction D3 of the linkage shaft 31 when the linkage shaft 31 is in the initial position P4.

[0103] According to this structure, the housing component 32 can be compactly formed, thereby enabling the neutral return mechanism 26 to be compactly formed.

[0104] Furthermore, the spring receiving part 40 includes a first spring bearing member 62 and a second spring bearing member 63 located at a distance between the neutral return spring 33, which is formed by a helical spring, and is housed on the axial direction D3 of the linkage shaft 31. The linkage shaft 31 has an end portion 38 provided on the other end side opposite to one end side of the linkage shaft 31. The first spring bearing member 62 is restricted by the support part 39 to move in the direction of the linkage shaft 31 protruding from the housing part 32, i.e., the protrusion direction D4, and moves integrally with the linkage shaft 31 in the direction opposite to the protrusion direction D4, i.e., the retraction direction D5. The second spring bearing member 63 is restricted by the portion on the housing part 32 side (spring receiving part 40, sleeve 40B) to move in the retraction direction D5 and moves integrally with the end portion 38 in the protrusion direction D4.

[0105] According to this configuration, the neutral return spring 33 can be compactly housed within the spring receiving portion 40.

[0106] In addition, the linkage shaft 31 has a stop mechanism 70, which keeps the linkage shaft 31 in the operating position (stop position P7) outside the range of the range of the stroke H1 and H2 of the linkage shaft 31 that the linkage shaft 31 automatically returns to the initial position P4 before operation by the neutral return spring 33 after the linkage shaft 31 moves from the position operated by the operating member 80.

[0107] According to this configuration, the operating component 80 can be kept outside the range of the stroke H1, H2 of the linkage shaft 31 that automatically returns via the neutral return spring 33.

[0108] Furthermore, the stop mechanism 70 has a stop ball 71, a pressing ball 72, and a force-applying member 73 housed at the end 38 on the other end side of the linkage shaft 31. The stop ball 71 moves freely in the radial direction of the linkage shaft 31 and protrudes from the end 38 toward the radially outer side of the linkage shaft 31 outside the range of strokes H1 and H2, engaging with the engaging recess 90 provided in the spring housing 40 to hold the linkage shaft 31 in the operating position (stop position P7). The pressing ball 72 presses the stop ball 71 toward the radially outer side of the linkage shaft 31 using the force of the force-applying member 73.

[0109] According to this configuration, a stop mechanism 70 can be realized that keeps the operating component 80 outside the range of the stroke H1, H2 of the linkage shaft 31, which automatically returns via the neutral return spring 33.

[0110] While one embodiment of the invention has been described above, the disclosed embodiments are illustrative in all respects and should not be considered limiting. The scope of the invention is not defined by the foregoing description but by the scope of the claims, which includes all modifications within the scope of the claims.

[0111] (Label Explanation)

[0112] 26 Neutral Return Agency

[0113] 27 Rotating shaft

[0114] 29. Linkage Arm

[0115] 31 linkage shaft

[0116] 32. Housing components

[0117] 33 Neutral Return Spring

[0118] 34 Connecting parts

[0119] 38 end

[0120] 39 Supported part

[0121] 40 Spring receiving part (part on the housing component side)

[0122] 40B Sleeve (part on the housing component side)

[0123] 48 Protruding mouth

[0124] 50 Bearing section

[0125] 53 Bracket Components

[0126] 62 First spring bearing component

[0127] 63 Second spring bearing component

[0128] 70 Stopping Mechanism

[0129] 71. Stop ball

[0130] 72 Pressing Ball

[0131] 73 Force-applying components

[0132] 90 engagement recess

[0133] 80 Operating components

[0134] C1 Hydraulic Actuator

[0135] D1 One direction

[0136] D2 Another direction

[0137] D3 Axis direction (direction of the linkage axis)

[0138] D4 Prominent Direction

[0139] D5 Retreat Direction

[0140] H1 Itinerary

[0141] H2 Itinerary

[0142] L1 Axial length

[0143] L2 length

[0144] P1 Neutral Position

[0145] P4 Initial Position

[0146] P5 Move position (first move position)

[0147] P6 Move position (second move position)

[0148] V1 control valve

[0149] X2 axis (rotation axis)

[0150] X3 axis

[0151] X4 axis.

Claims

1. A neutral return mechanism, capable of oscillating from a neutral position about a rotation axis in one direction and in the opposite direction (i.e., another direction) and returning an operating component of an operating control valve to the neutral position, wherein the control valve hydraulically controls a hydraulic actuator. The neutral return mechanism has the following features: The linkage shaft is pushed or pulled in the axial direction in conjunction with the swing operation of the operating component; A housing component that supports the linkage shaft in a manner that allows it to move along the axial direction and allows one end of the linkage shaft to protrude. A neutral return spring returns the linkage shaft from its moved position after being operated by the operating component to its initial position before operation. The neutral return spring is housed within the housing component along the axial direction of the linkage shaft. The linkage shaft has a connecting portion pivotally supported and connected to the linkage arm. The linkage arm and the swinging operation of the operating component are linked together, with the linkage protruding radially outward from the rotation axis. The rotation axis rotates about a rotation axis that is parallel to and perpendicular to the axis of the linkage shaft. The housing component has a supported portion, which is supported by a bracket component between a spring receiving portion that houses the neutral return spring and a protrusion for the linkage shaft to protrude. The supported portion has a bearing portion extending in a direction parallel to the axis of rotation and perpendicular to the axis of linkage. The bearing portion is supported on the bracket component by a pivot support pin in a manner that allows it to rotate about an axis extending from the supported portion.

2. The neutral return mechanism according to claim 1, wherein, The spring receiving portion and the supported portion are arranged adjacent to each other in the axial direction of the linkage shaft. The spring receiving portion has a cylindrical receiving hole concentric with the axis of the linkage shaft, and the receiving hole is formed as an opening on the side of the supported portion. The supported part has a through hole and the protrusion. The linkage shaft is inserted through the through hole, which is connected to the receiving hole and is formed in a through shape in the axial direction of the linkage shaft.

3. The neutral return mechanism according to claim 1, wherein, The axial length of the linkage shaft within the supported portion is less than the length of the neutral return spring in the axial direction of the linkage shaft when the linkage shaft is in its initial position.

4. The neutral return mechanism according to any one of claims 1 to 3, wherein, The neutral return mechanism includes a first spring bearing component and a second spring bearing component within the spring receiving portion. The first spring bearing component and the second spring bearing component are housed at a distance from each other in the axial direction of the linkage shaft, and a neutral return spring composed of a helical spring is sandwiched between the first spring bearing component and the second spring bearing component. The linkage shaft has an end, which is located on the opposite side of the first end, i.e., the other end. The first spring-bearing component is restricted from moving in the protruding direction by the supported portion and moves integrally with the linkage shaft in the retraction direction, which is the direction in which the linkage shaft protrudes from the housing component. The second spring bearing member is restricted from moving in the retraction direction by a portion on the side of the housing member and moves integrally with the end in the protruding direction.

5. The neutral return mechanism according to any one of claims 1 to 3, wherein, The linkage shaft has a stop mechanism that holds the linkage shaft in the post-operation position outside the range of the linkage shaft's travel distance from the moving position after being operated by the operating component to the initial position before operation via the neutral return spring.

6. The neutral return mechanism according to claim 5, wherein, The stopping mechanism includes a stopping ball, a pressing ball, and a force-applying component housed at the other end of the linkage shaft. The stop ball is freely movable in the radial direction of the linkage shaft and protrudes radially outward from the end of the linkage shaft outside the range of the stroke, engaging with the engaging recess provided in the spring receiving part to hold the linkage shaft in the position after operation. The pressing ball uses the force of the force-applying component to press the stop ball radially outward toward the linkage shaft.

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