Neutral return mechanism

Abstract

A neutral return mechanism (26) comprises: an interlocking shaft (31) that is pushed and pulled in an axial direction (D3) in conjunction with a pivoting operation of an operation member (80); a housing member (32) in which the interlocking shaft (31) is supported so as to be capable of movement in the axial direction and accommodated with one side thereof protruding; and a neutral return spring (33) that returns the interlocking shaft (31) to an initial position (P4) prior to being operated from a movement position (P5, P6) by the operation member (80), and that is accommodated along the axial direction (D3) of the interlocking shaft (31) within the housing member (32). The housing member (32) has a supported section (39) supported by a bracket member (53) between a protrusion hole (48) from which the interlocking shaft (31) protrudes and a spring accommodation section (40) in which the neutral return spring (33) is accommodated.

Description

[Technical field]

[0001] The present invention relates to a neutral return mechanism that returns an operating member such as a lever or a pedal to a neutral position. [Background technology]

[0002] 2. Description of the Related Art A working machine disclosed in Patent Document 1 is known in the art. The working machine disclosed in Patent Document 1 is provided with an operating member (dozer lever) that can be swung in one direction and the other direction from a neutral position and that operates a control valve that hydraulically controls a hydraulic actuator. The operating member operates a pilot valve, which in turn operates a control valve that hydraulically controls a hydraulic actuator. A neutral return mechanism that returns the operating member to a neutral position is incorporated in the pilot valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication "JP Patent Publication No. 2015-22642" Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there is a demand for a compact neutral return mechanism that returns an operating member that operates a hydraulic actuator to a neutral position. The present invention aims to provide a compact neutral return mechanism that can be operated to swing in one direction from a neutral position and in another direction opposite to the one direction, and that returns to a neutral position an operating member that operates a control valve that hydraulically controls a hydraulic actuator. [Means for solving the problem]

[0005] The neutral return mechanism according to one aspect of the present invention is configured to move in one direction from a neutral position and in another direction opposite to the one direction. Around the rotation axisA neutral return mechanism for returning an operating member that can be swung and that operates a control valve that hydraulically controls a hydraulic actuator to the neutral position, the neutral return mechanism comprising: an interlocking shaft that is pushed and pulled in an axial direction in association with the swinging operation of the operating member; a housing member that supports the interlocking shaft so that it can move in the axial direction and that accommodates the interlocking shaft so that one end side of the interlocking shaft protrudes; and a neutral return spring that returns the interlocking shaft from a moved position operated by the operating member to an initial position before the operation, the neutral return spring being accommodated in the housing member along the axial direction of the interlocking shaft, the interlocking shaft has a connecting portion that is pivotally connected to an interlocking arm that protrudes radially outward from a rotation shaft that rotates about the rotation axis parallel to a direction perpendicular to the axis of the interlocking shaft in response to the pivoting operation of the operating member, The housing member has a supported portion supported by a bracket member between a spring accommodating portion that accommodates the neutral return spring and a projection opening from which the interlocking shaft projects. The supported portion has a bearing portion extending in a direction parallel to the axis of the rotating shaft and perpendicular to the axis of the interlocking shaft, and the bearing portion is supported on the bracket member via a pivot pin so as to be rotatable around the axis in the direction extending from the supported portion.

[0006] Also, The spring accommodating portion and the supported portion are provided adjacent to each other in the axial direction of the interlocking shaft, the spring accommodating portion has a cylindrical accommodating hole concentric with the axial center of the interlocking shaft and an opening formed on the supported portion side, and the supported portion has a through hole through which the interlocking shaft is inserted, the through hole communicating with the accommodating hole and formed to pass through in the axial direction of the interlocking shaft, and the protrusion. . Further, the axial length of the interlocking shaft within the supported portion is smaller than the axial length of the neutral return spring of the interlocking shaft when the interlocking shaft is in the initial position.

[0007] The neutral return mechanism further comprises a first spring support member and a second spring support member which are accommodated in the spring accommodating portion at a distance from each other in the axial direction of the interlocking shaft and have the neutral return spring composed of a coil spring interposed between them, the interlocking shaft having an end portion provided on the other end side opposite the one end side of the interlocking shaft, the first spring support member being restricted in its movement in a protruding direction, in which the interlocking shaft protrudes from the housing member, by the supported portion and moving integrally with the interlocking shaft in a retracting direction, in the direction opposite to the protruding direction, and the second spring support member being restricted in its movement in the retracting direction by a portion on the housing member side and moving integrally with the end portion in the protruding direction.

[0008] The actuator further has a detent mechanism that holds the interlocking shaft in the operated position outside the stroke range of the interlocking shaft, which is the range in which the interlocking shaft automatically returns from the moved position operated by the operating member to the initial position before being operated by the neutral return spring. The detent mechanism further includes a detent ball, a pressure ball, and a biasing member housed in an end portion on the other end side of the interlocking shaft, the detent ball being movable radially of the interlocking shaft and protruding radially outward from the end portion outside the stroke range and engaging with an engagement recess provided in the spring accommodating portion to hold the interlocking shaft in a position where it is operated, and the biasing force of the biasing member presses the detent ball radially outward of the interlocking shaft. Effect of the Invention

[0009] According to the above-mentioned neutral return mechanism, the neutral return spring that returns the interlocking shaft, which is pushed and pulled in the axial direction in conjunction with the swinging operation of the operating member, from a moved position to an initial position is accommodated within the housing member along the axial direction of the interlocking shaft, and a supported portion supported by the bracket member is provided in the housing member between the spring accommodating portion and the opening from which the interlocking shaft protrudes, thereby making it possible to configure a compact mechanism. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a side cross-sectional view of the neutral return mechanism according to the first embodiment. [Diagram 2] FIG. 2 is a side view showing an attached state of the neutral return mechanism according to the first embodiment. [Diagram 3] FIG. 2 is a front view showing an attached state of the neutral return mechanism according to the first embodiment. [Figure 4] FIG. 2 is a perspective view showing a state in which the neutral return mechanism according to the first embodiment is attached. [Diagram 5] FIG. 11 is a side cross-sectional view of a neutral return mechanism according to a second embodiment. [Figure 6] FIG. [Figure 7] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 show a first embodiment of the neutral return mechanism 26. Fig. 1 is a side cross-sectional view of the neutral return mechanism 26, Fig. 2 is a side view showing the installation state of the neutral return mechanism 26, and a front view showing the installation state of the neutral return mechanism 26, Fig. 3 is a front view showing the installation state of the neutral return mechanism 26, and Fig. 4 is a perspective view showing the neutral return mechanism 26 installed on an operating member.

[0012] The neutral return mechanism 26 is a mechanism for returning the swingable operating member 80 from the operated position to the neutral position P1. As shown in Fig. 4, in this embodiment, the operating member 80 is configured as a lever. The operating member 80 may be a pedal. The lever 80 has a grip 80A that is held by an operator, and a lever shaft 80B to which the grip 80A is attached at the upper part. One end of a rotation shaft 27 that is rotatable around an axis (rotation axis) X2 that extends in a direction perpendicular to an axis X5 of the lever shaft 80B is fixed to the lower end side of the lever shaft 80B.

[0013] 2, the rotating shaft 27 is attached to the wall 54 to which the neutral return mechanism 26 is attached by a shaft attachment member (not shown), and is supported by the shaft attachment member so as to be rotatable about a rotation axis X2. An interlocking arm 29 is fixed to the rotating shaft 27. The interlocking arm 29 protrudes from the rotating shaft 27 radially outward. As shown by the dotted line in Figure 2, the lever 80 can be swung to a first operating position P2, which is a position where the lever shaft 80B is swung in one direction D1 around the rotation axis X2 from a neutral position P1, where the lever shaft 80B extends in the vertical direction, and to a second operating position P3, which is a position where the lever 80 is swung from the neutral position P1 in another direction D2, which is the opposite direction to the one direction D1, around the rotation axis X2.

[0014] As shown in FIG. 4, the operation direction (swing direction) and operation amount (swing amount) of the lever 80 are detected by an angle sensor S1. The angle sensor S1 is composed of, for example, a potentiometer. The angle sensor S1 is connected to a control device U1. The control device U1 can acquire detection information (operation direction and operation amount of the lever 80) of the angle sensor S1. Therefore, a detection signal detected by the angle sensor S1 is sent to the control device U1, and the control device U1 electrically controls a control valve (hydraulic solenoid valve) V1 that hydraulically controls a hydraulic cylinder C1, which is an operation object operated by the lever 80, based on the detection signal of the angle sensor S1. In other words, when the lever 80 is operated, the control device U1 controls the current supplied to the control valve V1 (or transmits a signal to the control valve V1), and the hydraulic cylinder C1 operates. Therefore, the lever 80 is an operation member that operates the control valve V1 that hydraulically controls the hydraulic cylinder (hydraulic actuator) C1, and is used to electrically control the control valve V1 that hydraulically controls the hydraulic cylinder (hydraulic actuator) C1.

[0015] As shown in Figs. 1 and 2, the neutral return mechanism 26 has an interlocking shaft 31, a housing member 32, and a neutral return spring 33. The interlocking shaft 31 has a bifurcated connecting portion 34 at one end side (one end side in the axial direction) 35A in the axial direction D3. The connecting portion 34 is pivotally connected to the interlocking arm 29 by a connecting pin 36. Therefore, when the lever 80 is swung to rotate the rotating shaft 27, the interlocking arm 29 swung about the rotation axis X2, and the interlocking shaft 31 is pushed and pulled in the axial direction. In other words, the interlocking shaft 31 is pushed and pulled in the axial direction D3 in conjunction with the swinging operation of the lever (operating member) 80.

[0016] As shown in FIG. 1, the other end side (the other end side in the axial direction) 35B of the interlocking shaft 31 in the axial direction (also called the interlocking shaft axial direction) D3 is formed with a small diameter portion 31B formed with a diameter smaller than the outer diameter of the shaft body 31A of the interlocking shaft 31. Also, the other end side 35B in the axial direction of the interlocking shaft 31 is formed with a screw hole 37 along the interlocking shaft axial direction D3 from the other end side 35B to the one end side 35A (from the small diameter portion 31B to the shaft body 31A). The screw hole is a hole with a female thread on the inner surface of the hole. Also, the interlocking 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 is screwed into the screw hole 37 and attached 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 interlocking shaft 31.

[0017] 1, the housing member 32 supports the interlocking shaft 31 movably in the axial direction D3 and accommodates the interlocking shaft 31 so that one end side (axial end side 35A) of the interlocking shaft 31 protrudes. In other words, the housing member 32 supports the interlocking shaft 31 movably in a protruding direction D4, which is the direction in which the interlocking shaft 31 protrudes from the housing member 32, and a retracting direction D5, which is the opposite direction to the protruding direction D4.

[0018] The housing member 32 has a supported portion 39 on one axial end side 35A of the interlocking shaft 31, and a spring accommodating portion 40 on the other axial end side 35B of the interlocking shaft 31. The supported portion 39 and the spring accommodating portion 40 are formed separately. The supported portion 39 has a through hole 46 formed penetrating in the axial direction D3 of the interlocking shaft. The interlocking shaft 31 has a shaft body 31A inserted into the through hole 46, and is supported by the supported portion 39 via a bush 47 fitted into the inner surface of the through hole 46 so as to be movable in the axial direction D3. One end side (one end side 35A in the axial direction) of the through hole 46 is formed as a protruding opening 48 from which the interlocking shaft 31 protrudes. Therefore, the supported portion 39 is provided between the spring accommodating portion 40 and the protruding opening 48. A dust seal 49 is provided on the protruding opening 48 side of the bush 47.

[0019] As shown in FIG. 1, the supported portion 39 is formed with a bearing portion 50 and a connecting portion 51. As shown in FIG. 3, the bearing portion 50 includes a first bearing portion 50A and a second bearing portion 50B that extend integrally from the main body portion 39A of the supported portion 39, which is the portion where the through hole 46 is formed. The first bearing portion 50A extends in a direction D6 perpendicular to the axis X3 of the interlocking shaft 31. The first bearing portion 50A has a first support hole 52A formed from the extending end toward the main body portion 39A. The second bearing portion 50B extends in a direction D7 perpendicular to the axis X3 of the interlocking shaft 31, 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 the extending end toward the main body portion 39A. The first support hole 52A and the second support hole 52B have concentric axes perpendicular to the axis X3 of the interlocking shaft 31.

[0020] 2 and 3, the supported portion 39 is pivotally supported by a 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. 2, the upper wall 53a is disposed above the supported portion 39 and the axial one end side 35A of the interlocking shaft 31, and is attached by bolts 56 to a protruding portion 55 that protrudes downward from a wall portion 54 located above the bracket member 53. The first side wall 53b extends from the upper wall 53a toward the first bearing portion 50A, and has a first pivot wall 53d located to the side of the first bearing portion 50A. A first pivot pin that penetrates the first pivot wall 53d and is inserted into the first support hole 52A is attached to the first pivot wall 53d. (Pivot pin) The first bearing portion 50A is pivotally supported by the second support hole 52B. The second side wall 53c extends from the upper wall 53a toward the second bearing portion 50B and has a second pivot wall 53e located to the side of the second bearing portion 50B. A second pivot pin is inserted through the second pivot wall 53e and into the second support hole 52B. (Pivot pin) The second bearing portion 50B is pivotally supported by 57B.

[0021] 2, the first pivot pin 57A and the second pivot pin 57B have an axis X4 parallel to the rotation axis X2. That is, the supported portion 39 is supported by the bracket member 53 to be rotatable about an axis parallel to the axis of the rotation shaft 27 (rotation axis X2). As shown in FIG. 3, the first pivot pin 57A and the second pivot pin 57B are prevented from coming off by a retaining member 58.

[0022] As shown in Fig. 3, a pair of connecting parts 51 are provided. One connecting part 51 extends in a direction perpendicular to the axis of the interlocking shaft 31. The other connecting part 51 extends in a direction perpendicular to the axis X3 of the interlocking shaft 31, in a direction opposite to the direction in which the one connecting part 51 extends. As shown in Fig. 1, each connecting part 51 is formed with a screw hole 51a. 1, the spring accommodating portion 40 has a cylindrical accommodating hole 59 that is concentric with the axis X3 of the interlocking shaft 31. The accommodating hole 59 is formed in a bottomed cylindrical shape that is open at one axial end side 35A of the interlocking shaft 31 and closed at the other axial end side 35B. The accommodating hole 59 communicates with the through hole 46 of the supported portion 39, and the other axial end side of the interlocking shaft 31 is inserted into the accommodating hole 59.

[0023] The spring accommodating portion 40 has a pair of connecting portions 60 corresponding to the connecting portions 60 of the supported portion 39. A screw hole 60a is formed through the connecting portions 60. The connecting portions 51 and 60 are screwed together by screwing a bolt 61 into the screw holes 51a, 60a, thereby connecting the supported portion 39 and the spring accommodating portion 40. The neutral return spring 33 is accommodated in the accommodation hole 59 (inside the housing member 32). The neutral return spring 33 is formed by a compression coil spring, and is accommodated concentrically in the accommodation hole 59. In other words, the neutral return spring 33 is accommodated in the housing member 32 along the interlocking shaft axial direction D3.

[0024] A first spring support member 62 and a second spring support member 63 that receive the load of the neutral return spring 33 are housed in the housing hole 59. The first spring support member 62 and the second spring support member 63 are housed in the spring housing portion 40 with a gap therebetween in the axial direction D3 of the interlocking shaft. The neutral return spring 33 is interposed between the first spring support member 62 and the second spring support member 63. The first spring bearing member 62 has a cylindrical portion 62a arranged on the outer circumferential side of the shaft body 31A of the interlocking shaft 31, a first portion 62b extending radially outward from one end side of the cylindrical portion 62a and abutting against the supported portion 39, and a second portion 62c extending radially inward from the other end side of the cylindrical portion 62a and engaging with a step portion 64 between the shaft body 31A and the small diameter portion 31B. Therefore, the movement of the first spring bearing member 62 in the protruding direction D4 is restricted by the supported portion 39, and it moves integrally with the interlocking shaft 31 in the retracting direction D5.

[0025] The second spring receiving member 63 has a tubular portion 63a disposed outside the head portion 38a of the end portion 38, a first portion 63b extending radially inward from one end side of the tubular 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 side of the tubular portion 63a and abutting against the spring accommodating portion 40. Therefore, the movement of the second spring receiving member 63 in the retracting direction D5 is restricted by the portion on the housing member 32 side (the spring accommodating portion 40), and the second spring receiving member 63 moves integrally with the end portion 38 (the interlocking shaft 31) in the protruding direction D4.

[0026] 1 and 2, in the neutral return mechanism 26, when the lever 80 is in the neutral position P1, the interlocking shaft 31 is in an initial position P4 (neutral position of the interlocking shaft 31), which is the position before the lever 80 is operated. In this initial position P4, the interlocking shaft 31 is disposed so that the axis X3 extends horizontally. When the lever 80 is operated from the neutral position P1 to the first operating position P2, the interlocking shaft 31 moves from the initial position P4 to a first moving position (moving position) P5, which is a position operated by the lever 80. When the interlocking shaft 31 moves to the first moving position P5, the second spring support member 63 moves integrally with the end portion 38 (interlocking shaft 31) in the protruding direction D4, and the neutral return spring 33 is compressed.

[0027] Furthermore, when the lever 80 is operated from the neutral position P1 to the second operating position P3, the interlocking shaft 31 moves from the initial position P4 to a second movement position (movement position) P6, which is a position operated by the lever 80. When the interlocking shaft 31 moves to the second movement position P6, the first spring support member 62 moves integrally with the step portion 64 (interlocking shaft 31) in the retraction direction D5, and the neutral return spring 33 is compressed.

[0028] By compressing the neutral return spring 33, an operation load is applied to the lever 80. In addition, by adopting (replacing) a neutral return spring 33 with a different load, the operation load of the lever 80 can be changed. When the operating force of the lever 80 is released or the lever 80 is returned to the neutral position P1, the biasing force of the neutral return spring 33 causes the interlocking shaft 31 to return from the movement position (the first movement position P5 or the second movement position P6) to the initial position P4.

[0029] In addition, the stroke H1 between the initial position P4 and the first moving position P5, and the stroke H2 between the initial position P4 and the second moving position P6 are set, for example, to be approximately the same as the distance H3 between the second portion 62c and the first portion 63b when the interlocking shaft 31 is in the initial position P4. 1, in the neutral return mechanism 26 configured as described above, the axial length L1 of the interlocking shaft 31 in the supported portion 39 is smaller than the length L2 in the axial direction D3 of the neutral return spring 33 when the interlocking shaft 31 is in the initial position P4, thereby forming a compact neutral return mechanism 26. In addition, the length L3 in the axial direction D3 of the supported portion 39 is smaller than the length L4 in the axial direction D3 of the spring housing portion 40.

[0030] Also, for example, if a stay member is fixed to the other axial end side 35B of the interlocking shaft 31 in the spring accommodating portion 40 to pivotally support the housing member 32 on the wall portion 54 side, and this stay member is pivotally supported by a bracket member attached to the wall portion 54, the neutral return mechanism 26 will become larger in size in the axial direction D3 of the interlocking shaft. In contrast, in this embodiment, a supported portion 39 pivotally supported by a bracket member 53 attached to the wall portion 54 is provided between the spring accommodating portion 40 and the protruding opening 48, so that the neutral return mechanism 26 can be formed compactly.

[0031] In the above embodiment, the supported portion 39 is pivotally supported (supported to be rotatable about the axis X4) by the bracket member 53, but the present invention is not limited to this and the supported portion 39 may be fixedly supported (supported non-rotatably) by the bracket member 53. In this case, although not limited to this, for example, a pin insertion hole for inserting the connecting pin 36 is formed in the interlocking arm 29 as an elongated hole so that the interlocking shaft 31 moves linearly when the interlocking arm 29 moves about the rotation axis X2.

[0032] FIG. 5 shows a second embodiment of the return-to-neutral mechanism 26. In this second embodiment, end portion 38 and small diameter portion 31B are integrally formed, and small diameter portion 31B is formed separately from shaft body 31A, and a threaded shaft portion 65 formed integrally with small diameter portion 31B is screwed into a threaded hole 66 formed in shaft body 31A, thereby attaching small diameter portion 31B and end portion 38 to shaft body 31A.

[0033] The end portion 38 is formed in a cylindrical shape having an outer diameter larger than that of the small diameter portion 31B, and the outer diameter is formed to be substantially the same as that of the shaft body 31A. The first portion 63b of the second spring receiving member 63 engages with a step portion 67 between the small diameter portion 31B and the end portion 38. An accommodation chamber 68 is formed in the end portion 38. The accommodation chamber 68 is formed by drilling a hole extending in the axial direction D3 from the other axial end side 35B to the one end side 35A of the interlocking shaft 31. The accommodation chamber 68 includes a first accommodation chamber 68A at the one axial end side 35A of the interlocking shaft 31 and a second accommodation chamber 68B at the other axial end side 35B of the interlocking shaft 31. The first accommodation chamber 68A is formed by a hole with a smaller diameter than the second accommodation chamber 68B.

[0034] The end portion has a through-portion 69 formed radially penetrating from the inner surface of the second housing chamber 68B to the outer surface of the end portion . A detent mechanism 70 is accommodated in the accommodation chamber 68 (end portion 38). The detent mechanism 70 holds the interlocking shaft 31 in an operated position outside the range of strokes H1, H2 of the interlocking shaft 31, which is the range in which the interlocking shaft 31 automatically returns from the movement positions (first movement position P5, second movement position P6) to the initial position P4 by the neutral return spring 33. The detent mechanism 70 has a detent ball 71, a pressing ball 72, and a biasing member 73.

[0035] The detent ball 71 is accommodated in the second accommodation chamber 68B. More specifically, the detent ball 71 is disposed at a position corresponding to the through-hole 69, and is movable through the through-hole 69 in the radial direction of the end portion 38 (interlocking shaft 31). In the second embodiment, a plurality (four) of the through-holes 69 are formed at equal intervals in the circumferential direction of the end portion 38. A plurality (four) of the detent balls 71 are provided corresponding to the four through-holes 69.

[0036] The pressing ball 72 is disposed between the detent ball 71 and the first housing chamber 68A in the second housing chamber 68B. The pressing ball 72 is formed to have a size capable of pressing the four detent balls 71. The biasing member 73 is formed of a coil spring and is housed in the first housing chamber 68A, and biases the pressing ball 72. The biasing force of the biasing member 73 acts in a direction in which the pressing ball 72 presses the detent ball 71. In other words, the pressing ball 72 presses the detent ball 71 radially outwardly of the interlocking shaft 31 due to the biasing force of the biasing member 73.

[0037] In the second embodiment, the spring accommodating portion 40 includes an accommodating portion main body 40A and a sleeve 40B accommodated in the accommodating portion main body 40A. The accommodating portion main body 40A has an opening 74 on the other end side 35B in the axial direction of the interlocking shaft 31. The sleeve 40B is inserted into the accommodating portion main body 40A from the opening 74 and is prevented from coming off by a spacer 75 and a retaining member (snap ring) 79. The second portion 63c of the second spring receiving member 63 abuts against the sleeve 40B (the portion on the housing member 32 side), thereby restricting movement in the retracting direction D5.

[0038] The inner circumferential side of the sleeve 40B is provided with a tapered portion 88, a positioning protrusion 89, and an engagement recess 90, which are formed in this order from the other axial end side 35B to the one end side 35A of the interlocking shaft 31. The tapered portion 88, the positioning protrusion 89, and the engagement recess 90 are formed from the midpoint of the sleeve 40B in the axial direction toward the one end side 35A of the interlocking shaft 31. The tapered portion 88 is formed in a tapered shape that gradually increases in diameter from the other end side 35B in the axial direction of the interlocking shaft 31 toward the one end side 35A (positioning projection 89).

[0039] The positioning projection 89 is formed as a convex strip that projects toward the inner periphery of the sleeve 40B and is formed in the circumferential direction of the sleeve 40B. The engagement recess 90 is formed by a circumferential groove formed in the circumferential direction on the inner periphery of the sleeve 40B. 5, when the interlocking shaft 31 is in the initial position P4, the detent ball 71 is located on the other axial end side 35B of the interlocking shaft 31 relative to the tapered portion 88. When the lever 80 is operated from the neutral position P1 to the first operating position P2 and the interlocking shaft 31 moves to the first moving position P5, the detent ball 71 moves from the small diameter side to the large diameter side of the tapered portion 88 while moving radially outward of the interlocking shaft 31, and comes into contact with the positioning protrusion 89.

[0040] When the lever 80 is further swung in one direction D1 from the first operating position P2 from the position where the detent ball 71 abuts against the positioning projection 89 (when the interlocking shaft 31 is in the first moving position P5), the detent ball 71 climbs over the positioning projection 89 and fits into the engagement recess 90, and the interlocking shaft 31 moves to the detent position P7. When the detent ball 71 fits into the engagement recess 90, the interlocking shaft 31 does not return to the initial position P4 by the biasing force of the neutral return spring 33, and is held at the detent position P7. In other words, the detent ball 71 protrudes radially outward from the end portion 38 of the interlocking shaft 31 outside the range of strokes H1 and H2, which are the ranges for automatic return by the neutral return spring 33, and engages with the engagement recess 90 provided in the spring accommodating portion 40, thereby being able to hold the interlocking shaft 31 at the position where it was operated (detent position P7).

[0041] In the second embodiment, the distance H5 between the second portion 62c of the first spring support member 62 and the first portion 63b of the second spring support member 63 when the interlocking shaft 31 is in the initial position P4 is set to be approximately the same as the stroke H4 between the initial position P4 and the detent position P7. On the other hand, when the lever 80 is operated to the second operating position P3 and the interlocking shaft 31 is moved to the second moving position P6, the detent ball 71 moves the cylindrical portion of the inner surface of the sleeve 40B to the other axial end side 35B of the interlocking shaft 31.

[0042] The other configurations of the second embodiment are similar to those of the first embodiment, and therefore will not be described. 6 and 7 show a working machine 1 employing a neutral return mechanism 26. Fig. 6 is a schematic plan view showing the overall configuration of the working machine 1. Fig. 7 is a perspective view of a driving section of the working machine 1. In this embodiment, a backhoe, which is a rotating working machine, is exemplified as the working machine 1.

[0043] As shown in Fig. 6, the work machine 1 includes a machine body (swivel base) 2, a traveling device 3, and a work device 4. A cabin 5 is mounted on the machine body 2. Inside the cabin 5, a driver's seat 6 is provided where a driver (operator) is seated. In this embodiment, the direction toward the front of the driver seated in the driver's seat 6 of the work machine 1 (the direction of arrow A1 in Fig. 6) will be described as the forward direction, the direction toward the rear of the driver (the direction of arrow A2 in Fig. 6) as the rear direction, the direction of arrow K1 in Fig. 6 as the front-rear direction, the left side of the driver (the front side in Fig. 6) as the left side, and the right side of the driver (the back side in Fig. 6) as the right side. The horizontal direction that is perpendicular to the front-rear direction K1 will be described as the machine body width direction (the width direction of the machine body 2).

[0044] As shown in Fig. 6, the traveling device 3 has a traveling frame 3A, a first traveling device 3L provided on the left side of the traveling frame 3A, and a second traveling device 3R provided 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 configured by hydraulic motors (hydraulic actuators).

[0045] As shown in Fig. 6, a dozer device 7 is attached to the front of the traveling device 3. The dozer device 7 has a dozer arm 7A whose rear part is pivotally supported by the traveling frame 3A and can swing up and down, and a dozer blade 7B provided on the front part of the dozer arm 7A. The dozer device 7 can be raised and lowered (the dozer blade 7B can be raised and lowered) by extending and retracting a dozer cylinder (hydraulic actuator).

[0046] 6, the machine body 2 is supported on a traveling frame 3A so as to be rotatable about a rotation axis X1 via a rotation bearing 8. A support bracket 20 is provided at the front of the machine body 2, and a swing bracket 21 is supported on the support bracket 20 so as to be rotatable about a vertical axis (an axis extending in the up-down direction). As shown in FIG. 6, the working device 4 has a boom 22, an arm 23, and a bucket (working tool) 24. The base of the boom 22 is pivotally attached to an upper portion of the swing bracket 21 so as to be rotatable about a horizontal axis (an axis extending in the width direction of the machine body). The arm 23 is pivotally attached to the tip side of the boom 22 so as to be rotatable about the horizontal axis. The bucket 24 is provided at the tip side of the arm 23 so as to be capable of scooping and dumping operations. The scooping operation is an operation of swinging the bucket 24 in a direction approaching the boom 22, for example, an operation for scooping up soil and sand. The dumping operation is an operation of swinging the bucket 24 in a direction away from the boom 22, for example, an operation for dropping (discharging) the scooped up soil and sand.

[0047] The work machine 1 can be equipped with other working tools (hydraulic attachments) that can be driven by a hydraulic actuator, instead of or in addition to the bucket 24. Examples of other working tools include a hydraulic breaker, a hydraulic crusher, an angle broom, an earth auger, a pallet fork, a sweeper, a mower, and a snow blower. The swing bracket 21 can swing by extending and retracting a swing cylinder C2 provided on the machine body 2. The boom 22 can swing by extending and retracting a boom cylinder C3. The arm 23 can swing by extending and retracting an arm cylinder C4. The bucket 24 can perform scooping and dumping operations by extending and retracting a bucket cylinder C5. The swing cylinder C2, boom cylinder C3, arm cylinder C4, and bucket cylinder C5 are hydraulic cylinders (hydraulic actuators).

[0048] As shown in Fig. 6, a control device 41 is provided inside the cabin 5. The control device 41 is provided in front of the driver's seat 6. The driver's seat 6 and the control device 41 constitute a driving section 42 that drives the work machine 1 (controls the machine body 2, the traveling device 3, the work device 4, the swing bracket 21, etc.). 7, the driver's seat 6 is supported via a seat base 76 and the like on a floor portion 5B that constitutes the bottom of the cabin 5. A suspension device 77 is provided on the seat base 76, and the driver's seat 6 is provided on the suspension device 77 via a slide rail 78 so that its position can be adjusted forward and backward.

[0049] As shown in FIG. 7, the control device 41 includes a control stand 81, a control member 82, a monitor 84, a travel pedal 85, a lever 80, and the like. The control console 81 is provided in front of the driver's seat 6 on the aircraft body 2, and has a base 86 erected on the floor 5B (aircraft body 2) and a control console main body 87 arranged on the upper part of the base 86. The control members 82 are members that are held and operated by the operator, and are attached to the control platform main body 87 (control platform 81). The control members 82 include a first control handle 82L and a second control handle 82R that are arranged side by side in the width direction of the machine body. The first control handle 82L and the second control handle 82R can be used to perform, for example, rotation operation of the machine body 2, swing operation of the boom 15, swing operation of the arm 23, and swing operation of the bucket 24.

[0050] As shown in Fig. 7, the control console main body 87 has armrests 93 provided on the left and right sides of the control console main body 87. The first armrest 93L, which is the left armrest 93, has an armrest base 93L1 and an armrest main body 93L2 pivotally supported at the rear of the armrest base 93L1. The second armrest 93R, which is the right armrest 93, has an armrest base 93R1 and an armrest main body 93R2 formed integrally with the armrest base 93R1. The armrest main body 93L2 and the armrest main body 93R2 have elbow rests 93A at their rear on which the driver's elbows are placed.

[0051] The lever 80 is a dozer lever 80 that operates the dozer device 7. The dozer lever 80 can be swung forward (one direction D1) and backward (the other direction D2) from a neutral position P1. The neutral return mechanism 26 of the first and second embodiments is used to return the dozer lever 80 to the neutral position P1. The second armrest 93R is hollow, and the neutral return mechanism 26 and the rotating shaft 27 are housed inside an armrest base 93R1 of the second armrest 93R. The wall portion 54 to which the neutral return mechanism 26 and the rotating shaft 27 are attached is the upper wall of the second armrest 93R.

[0052] The neutral return mechanism 26 can be used to return the travel pedal 85 to the neutral position. The neutral return mechanism 26 can also be used to return a swing pedal that swings the swing bracket 21 to the neutral position. The neutral return mechanism 26 can also be used to return an AUX pedal that operates a hydraulic attachment that is attached instead of or in addition to the bucket 24 to the neutral position. The neutral return mechanism 26 may also be used to return other levers and pedals to the neutral position.

[0053] In the neutral return mechanism 26 of the second embodiment, a dozer control valve is provided with a floating position that allows the dozer blade 7B to descend under its own weight (allowing the hydraulic cylinder that moves the dozer arm 7A up and down to freely expand and contract). In the neutral return mechanism 26 of the second embodiment, the dozer control valve is switched to the floating position by moving the interlocking shaft 31 to the detent position P7. In other words, by holding the interlocking shaft 31 at the detent position P7, the dozer control valve can be held at the floating position.

[0054] The neutral return mechanism 26 of this embodiment is a neutral return mechanism that returns an operating member 80 that can be swung from a neutral position P1 in one direction D1 and in another direction D2 that is the opposite direction of the one direction D1 and that operates a control valve V1 that hydraulically controls a hydraulic actuator C1 to the neutral position P1. The neutral return mechanism 26 includes an interlocking shaft 31 that is pushed and pulled in an axial direction D3 in conjunction with the swinging operation of the operating member 80, and a housing that supports the interlocking shaft 31 movably in the axial direction D3 and accommodates the interlocking shaft 31 so that one end side of the interlocking shaft 31 protrudes. The housing member 32 includes a neutral return spring 33 that returns the interlocking shaft 31 from a moving position (first moving position P5, second moving position P6) operated by the operating member 80 to an initial position P4 before the operation, the neutral return spring 33 being accommodated within the housing member 32 along the axial direction D3 of the interlocking shaft 31, and the housing member 32 has a supported portion 39 supported by the bracket member 53 between a spring accommodating portion 40 that accommodates the neutral return spring 33 and an opening 48 from which the interlocking shaft 31 protrudes.

[0055] According to this configuration, the neutral return spring 33, which returns the interlocking shaft 31, which is pushed and pulled in the axial direction D3 in conjunction with the swinging operation of the operating member 80, from the moving positions P5, P6 to the initial position P4, is accommodated within the housing member 32 along the axial direction of the interlocking shaft 31, and by providing the housing member 32 with a supported portion 39 supported by the bracket member 53 between the spring accommodating portion 40 and the projection port 48 from which the interlocking shaft 31 protrudes, the neutral return mechanism 26 can be formed compactly.

[0056] In addition, the interlocking shaft 31 has a connecting portion 34 that is pivotally connected to an interlocking arm 29 that protrudes radially outward from a rotating shaft 27 that rotates around an axis X2 parallel to a direction perpendicular to the axis X3 of the interlocking shaft 31 in response to the swinging motion of the operating member 80, and the supported portion 39 has a bearing portion 50 that is supported on a bracket member 53 so as to be rotatable around an axis X4 parallel to the axis of the rotating shaft 27.

[0057] According to this configuration, the neutral return mechanism 26 can be caused to follow the movement of the interlocking arm 29 around the rotation shaft 27 . Further, the axial length L1 of the interlocking shaft 31 within the supported portion 39 is smaller than the length L2 of the neutral return spring 33 in the axial direction D3 of the interlocking shaft 31 when the interlocking shaft 31 is in the initial position P4.

[0058] According to this configuration, the housing member 32 can be made compact, and therefore the neutral return mechanism 26 can be made compact. The spring accommodating portion 40 also includes a first spring support member 62 and a second spring support member 63 which are accommodated at a distance from each other in the axial direction D3 of the interlocking shaft 31 and have a neutral return spring 33 composed of a coil spring interposed therebetween. The interlocking shaft 31 has an end portion 38 provided on the other end side opposite to the one end side of the interlocking shaft 31. The first spring support member 62 is restricted in movement in the protruding direction D4, in which the interlocking shaft 31 protrudes from the housing member 32, by the supported portion 39, and moves integrally with the interlocking shaft 31 in the retracting direction D5, which is the direction opposite to the protruding direction D4. The second spring support member 63 is restricted in movement in the retracting direction D5 by a portion on the housing member 32 side (spring accommodating portion 40, sleeve 40B), and moves integrally with the end portion 38 in the protruding direction D4.

[0059] According to this configuration, the neutral return spring 33 can be accommodated compactly within the spring accommodating portion 40. In addition, the interlocking shaft 31 has a detent mechanism 70 that holds the interlocking shaft 31 in an operated position (detent position P7) outside the range of strokes H1, H2 of the interlocking shaft 31, within which the interlocking shaft 31 automatically returns from the moved position operated by the operating member 80 to the initial position P4 before operation by the neutral return spring 33.

[0060] According to this configuration, the operating member 80 can be held outside the range of strokes H1, H2 of the interlocking shaft 31 that is automatically returned by the neutral return spring 33. The detent mechanism 70 has a detent ball 71, a pressure ball 72 and a biasing member 73 housed in the end portion 38 on the other end side of the interlocking shaft 31, and the detent ball 71 is freely movable in the radial direction of the interlocking shaft 31 and protrudes radially outward from the end portion 38 outside the range of strokes H1, H2. The detent ball 71 can engage with an engagement recess 90 provided in the spring accommodating portion 40 to hold the interlocking shaft 31 in a position where it is operated (detent position P7), and the biasing force of the biasing member 73 presses the detent ball 71 radially outward on the interlocking shaft 31.

[0061] According to this configuration, it is possible to realize the detent mechanism 70 that holds the operating member 80 outside the range of strokes H1, H2 of the interlocking shaft 31 that is automatically returned by the neutral return spring 33. Although one embodiment of the present invention has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0062] 26 Neutral return mechanism 27 Rotating shaft 29 Interlocking Arm 31 Interlocking shaft 32 Housing material 33 Neutral return spring 34 Connecting part 38 End section 39 Supported part 40 Spring accommodating portion (housing member side portion) 40B Sleeve (Housing member side part) 48 Output 50 Bearing section 53 Bracket member 62 First spring support member 63 Second spring support member 70 Detent mechanism 71 Detent Ball 72 Pressing Ball 73 Pressing member 90 Engagement recess 80 Operating member C1 Hydraulic Actuator D1 One direction D2 Other direction D3 Axial direction (interlocking shaft axis direction) D4 Projection direction D5 Evacuation direction H1 Stroke H2 Stroke L1 Axial length L2 Length P1 neutral position P4 initial position P5 Movement position (1st movement position) P6 Movement position (2nd movement position) V1 Control valve X2 axis (rotation axis) X3 axis center X4 axis center

Claims

1. A neutral return mechanism that returns an operating member that can be pivoted around a rotation axis from a neutral position in one direction and in another direction opposite to the one direction and that operates a control valve that hydraulically controls a hydraulic actuator to the neutral position, An interlocking shaft that is pushed and pulled in an axial direction in conjunction with the swinging operation of the operating member; a housing member that supports the interlocking shaft so as to be axially movable and accommodates the interlocking shaft so that one end side of the interlocking shaft protrudes; a neutral return spring that returns the interlocking shaft from a moved position operated by the operating member to an initial position before the operation, the neutral return spring being accommodated in the housing member along the axial direction of the interlocking shaft; Equipped with the interlocking shaft has a connecting portion that is pivotally connected to an interlocking arm that protrudes radially outward from a rotation shaft that rotates about the rotation axis parallel to a direction perpendicular to the axis of the interlocking shaft in response to the pivoting operation of the operating member, The housing member includes: a support portion supported by a bracket member is provided between a spring accommodating portion that accommodates the neutral return spring and an opening from which the interlocking shaft protrudes, the supported portion has a bearing portion extending in a direction parallel to an axis of the rotation shaft and perpendicular to an axis of the interlocking shaft, The bearing portion is supported on the bracket member via a pivot pin so as to be rotatable about an axis extending from the supported portion.

2. The spring accommodating portion and the supported portion are provided adjacent to each other in an axial direction of the interlocking shaft, The spring accommodating portion has a cylindrical accommodating hole that is concentric with the axis of the interlocking shaft and that is open toward the supported portion, The neutral return mechanism according to claim 1, wherein the supported portion has a through hole through which the interlocking shaft is inserted, the through hole being connected to the accommodating hole and extending in the axial direction of the interlocking shaft, and the protrusion.

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

4. a first spring bearing member and a second spring bearing member that are accommodated in the spring accommodating portion at an interval in the axial direction of the interlocking shaft and between which the neutral return spring constituted by a coil spring is interposed; The interlocking shaft has an end portion provided on the other end side opposite to the one end side of the interlocking shaft, The first spring bearing member is restricted in movement in a protruding direction, which is a direction in which the interlocking shaft protrudes from the housing member, by the supported portion, and moves integrally with the interlocking shaft in a retracting direction, which is a direction opposite to the protruding direction, The neutral return mechanism according to any one of claims 1 to 3, wherein the second spring support member is restricted in its movement in the retraction direction by a portion on the housing member side and moves integrally with the end portion in the protruding direction.

5. The neutral return mechanism according to any one of claims 1 to 4, further comprising a detent mechanism for holding the interlocking shaft in an operated position outside a stroke range of the interlocking shaft within which the interlocking shaft is automatically returned by the neutral return spring from a moved position operated by the operating member to an initial position before the operation.

6. The detent mechanism includes a detent ball, a pressure ball, and a biasing member accommodated in an end portion on the other end side of the interlocking shaft, the detent ball is movable in the radial direction of the interlocking shaft, protrudes from the end portion in the radial direction of the interlocking shaft outside the range of the stroke, and engages with an engagement recess provided in the spring accommodating portion to hold the interlocking shaft in a position where it is operated, The neutral return mechanism according to claim 5 , wherein the pressing ball presses the detent ball radially outwardly of the interlocking shaft by the biasing force of the biasing member.

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