Hydrostatic stepless speed change mechanism and speed change device

Abstract

An HST and a speed change device, the HST of the present invention comprises a main plate and a sub-plate which clamp a central portion, a pump side inclined plate bracket and a motor side inclined plate bracket by inner surfaces facing each other. The main plate is provided with an extension area extending outward in the surface direction from the installation space of the central portion, the pump side inclined plate bracket and the motor side inclined plate bracket and the sub-plate when viewed along the direction in which the main plate and the sub-plate face each other.

Description

Technical Field

[0001] The present invention relates to a hydrostatic continuously variable transmission (HST) having a hydraulic pump and a hydraulic motor connected in fluidic connection, and a transmission device including the HST. Background Art

[0002] The HST capable of continuously variable speed change is suitably used as a part or the whole of a transmission device of a travel system in a working vehicle such as a combine harvester or a tractor.

[0003] Patent document 1 listed below discloses a transmission device that transmits rotational power from an engine arranged in the front to rear wheels serving as drive wheels, and includes a housing having an opening opened upward and an HST accommodated in the housing, wherein all components of the HST are supported by a cover that closes the opening.

[0004] The transmission described in Patent Document 1 is useful in that the HST can be removed by removing the cover from the case in a state where the case is provided.

[0005] However, in the structure described in Patent Document 1, all the components of the HST are supported by the cover in a cantilevered state, which leads to a problem of lack of support stability.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 53-016223 Summary of the invention

[0009] The present invention is made in view of the above-mentioned prior art, and its first object is to provide an HST that can be integrally mounted and removed from a transmission in a work vehicle without disassembling the components while stabilizing the support of the components including a central portion, a pump side swash plate bracket, and a motor side swash plate bracket.

[0010] In addition, the second object of the present invention is to provide a speed change device that changes the speed of rotational power input from a driving source working place, the speed change device maintaining the setting state of the transmission while seeking to stabilize the support of the HST components including the central part, the pump side inclined plate bracket and the motor side inclined plate bracket, and can be loaded and unloaded relative to the transmission without disassembling the HST.

[0011] In order to achieve the first object, the present invention provides an HST, comprising: a pump shaft; a pump body supported on the pump shaft in a manner that cannot rotate relative to each other; a pump side inclined plate that divides the capacity of the pump body; a pump side inclined plate bracket that supports the back side of the pump side inclined plate; a motor shaft; a motor body supported on the motor shaft in a manner that cannot rotate relative to each other; a motor side inclined plate that divides the capacity of the motor body; a motor side inclined plate bracket that supports the back side of the motor side inclined plate; a central part that directly or indirectly slides in contact with the pump body and the motor body and forms an oil passage that fluidly connects the two; and a main plate and a sub-plate that clamp the central part, the pump side inclined plate bracket and the motor side inclined plate bracket using inner surfaces that are opposite to each other, and an extension area is provided on the main plate that extends outward in the surface direction of the sub-plate than the installation space of the central part, the pump side inclined plate bracket and the motor side inclined plate bracket when viewed along the direction in which the main plate is opposite to the sub-plate.

[0012] According to the HST of the present invention, the support of the components including the center portion, the pump-side swash plate bracket, and the motor-side swash plate bracket can be stabilized, and the HST can be integrally attached to and detached from the transmission in the work vehicle without disassembling the components.

[0013] In a first example of one aspect, the HST is configured as a tandem type in which the pump body and the motor body are coaxially arranged on one side and the other side in the thickness direction of the central portion.

[0014] In a second example of one aspect, the pump body is arranged on one side of the central portion in the thickness direction, and the motor body is arranged on the other side of the central portion in the thickness direction with the axis thereof being parallel to the axis of the pump body at a different position.

[0015] In the above aspect, preferably, a pump-side recess into which the pump-side sloping plate bracket is engaged and a motor-side recess into which the motor-side sloping plate bracket is engaged are provided on the inner surface of at least one of the main plate and the sub-plate.

[0016] The pump side recess and the motor side recess are configured to prevent the pump side swash plate bracket and the motor side swash plate bracket from moving away from the central portion in the thickness direction or to prevent the pump side swash plate bracket and the motor side swash plate bracket from moving toward the central portion in the thickness direction.

[0017] In the above aspect, it is preferable that a central portion recess into which the central portion is inserted so as to be unable to move in the thickness direction is provided on the inner surface of at least one of the main plate and the sub-plate.

[0018] In another embodiment, the HST is a side-by-side type in which the pump body and the motor body are arranged parallel to each other on one side in the thickness direction of the central portion.

[0019] The HST of the other aspect may preferably include a common swash plate bracket integrally including the pump-side swash plate bracket and the motor-side swash plate bracket.

[0020] More preferably, a recessed portion for snapping into the common inclined plate bracket and at least one of the central portion is provided on the inner surface of at least one of the main plate and the sub-plate, so as to prevent the HST pre-assembly formed by the central portion, the pump shaft, the pump body, the pump side inclined plate, the motor shaft, the motor body, the motor side inclined plate and the common inclined plate bracket from moving in the axial direction of the pump shaft.

[0021] In the above-described various configurations, at least one of the pump-side swash plate bracket and the motor-side swash plate bracket supports the back surface of the corresponding swash plate so that the corresponding swash plate can swing about the swing axis.

[0022] In this case, it is preferable that the main plate is provided with a hydraulic servo mechanism that swings a movable swash plate, one of the pump-side swash plate and the motor-side swash plate, about a corresponding swing axis.

[0023] For example, the hydraulic servo mechanism comprises: a pushing piston, which is accommodated in the main board and can reciprocate in the pushing direction, and is operatively connected to the movable inclined plate via a connecting rod in such a manner that the movable inclined plate is swung around a swing axis in accordance with the movement along the pushing direction; a first working oil chamber and a second working oil chamber are formed on the main board in such a manner that the pushing piston can be pushed to one side and the other side of the pushing direction respectively by means of the supplied pressure oil; a switching slide valve, which switches the supply and discharge of pressure oil to the first working oil chamber and the second working oil chamber according to the switching direction position; an operating piston, which is accommodated in the main board and can reciprocate in the operating direction parallel to the switching direction, and is connected to the switching slide valve via a connecting pin; the first operating oil chamber and the second operating oil chamber are formed on the main board in such a manner that the operating piston can be pushed to one side and the other side of the operating direction respectively by means of the supplied pressure oil; and an operating valve, which switches the supply and discharge of pressure oil to the first operating oil chamber and the second operating oil chamber.

[0024] In this case, it is preferable that a manual operation mechanism capable of manually changing the switching direction position of the switching slide valve is provided on the main board.

[0025] In order to achieve the second object, the present invention provides a transmission device for changing the speed of rotational power input from a driving source working position, the transmission device comprising: a gearbox; an input-side transmission shaft, which is supported by the gearbox so as to be rotatable around an axis in a state of being operatively connected to the driving source; an input-side transmission gear, which is supported by the input-side transmission shaft in the gearbox so as to be non-rotatable relative to the input-side transmission shaft; an output-side transmission shaft, which is supported by the gearbox so as to be rotatable around an axis; an output-side transmission gear, which is supported by the output-side transmission shaft in the gearbox so as to be non-rotatable relative to the output-side transmission shaft; and an HST.

[0026] Furthermore, according to the transmission of the present invention, the HST components including the center portion, the pump side swash plate bracket, and the motor side swash plate bracket can be stably supported while maintaining the setting state of the transmission and can be attached to and detached from the transmission without disassembling the HST.

[0027] In the speed change device of the present invention, the HST comprises: a pump shaft; a pump body supported on the pump shaft in a non-rotatable manner; a pump side inclined plate dividing the capacity of the pump body; a pump side inclined plate bracket supporting the back side of the pump side inclined plate and having a through hole through which the pump shaft passes; a pump side transmission gear supported on a portion of the pump shaft extending from the pump side inclined plate bracket to the opposite side of the pump body in a non-rotatable manner; a motor shaft; a motor body supported on the motor shaft in a non-rotatable manner; a motor side inclined plate dividing the capacity of the motor body; a motor side inclined plate bracket supporting the back side of the motor side inclined plate and having a through hole through which the motor shaft passes; a motor side transmission gear supported on a portion of the motor shaft extending from the motor side inclined plate bracket to the opposite side of the motor body in a non-rotatable manner; a central portion forming an oil passage connecting the pump body and the motor body fluid; and a main plate and a sub-plate clamping the central portion, the pump side inclined plate bracket and the motor side inclined plate bracket by inner surfaces facing each other.

[0028] The gearbox has a peripheral wall and an opening provided in the peripheral wall, wherein the opening is set to a size that allows components other than the main board in the HST to be inserted when the HST is in an assembled state, and the main board can be loaded and unloaded relative to the outer surface of the peripheral wall of the gearbox when the components of the HST other than the main board are accommodated in the gearbox via the opening.

[0029] The pump-side transmission gear and the motor-side transmission gear are configured to mesh with the input-side transmission gear and the output-side transmission gear, respectively, in a state in which the main plate is attached to the outer surface of the peripheral wall of the transmission case.

[0030] In one form of the speed change device of the present invention, a supply oil passage is provided on the main board, one end of which is opened on the outer surface to form an inlet for introducing oil for replenishing the working oil of the HST, an oil passage for receiving a portion of the oil introduced into the supply oil passage is provided on the pump side inclined plate bracket and the motor side inclined plate bracket, an axial hole is provided on the pump shaft to receive at least a portion of the oil introduced into the oil passage of the pump side inclined plate bracket, and an axial hole is provided on the motor shaft to receive at least a portion of the oil introduced into the oil passage of the motor side inclined plate bracket.

[0031] The axial hole of the pump shaft and the axial hole of the motor shaft are configured to supply the introduced oil to the lubricated portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a power transmission diagram of a work vehicle to which the transmission device including the HST according to the first embodiment of the present invention is applied.

[0033] Figure 2 It is an exploded perspective view of the transmission case and the HST in the transmission device.

[0034] Figure 3 is an exploded perspective view of the HST.

[0035] Figure 4 is a cross-sectional top view of the HST.

[0036] Figure 5 is a hydraulic circuit diagram of the HST.

[0037] Figure 6 It is along Figure 4 Cross-sectional view along line VI-VI.

[0038] Figure 7 It is along Figure 4 Cross-sectional view along line VII-VII.

[0039] Figure 8 It is along Figure 4 Cross-sectional view along line VIII-VIII in FIG.

[0040] Fig. 9 It is along Figure 4 Cross-sectional view along line IX-IX.

[0041] Fig.10 It is along Figure 4 Cross-sectional view of line XX.

[0042] Fig.11 It is along Figure 4 Cross-sectional view along line XI-XI.

[0043] Fig.12 This is a front view of the HST in a state of being assembled to the transmission as seen from the outside of the transmission, and is shown in cross section. Figure 2 Part XII of the .

[0044] Fig.13 It is along Fig.12 Cross-sectional view along line XIII-XIII in FIG.

[0045] Fig.14 It is along Figure 4 Cross-sectional view along line XIV-XIV in FIG.

[0046] Fig.15 It is a transmission diagram of a work vehicle to which another transmission device including the HST is applied.

[0047] Fig.16 is a longitudinal sectional view of an HST according to a second embodiment of the present invention, and is Figure 6 Corresponding longitudinal section view.

[0048] Fig.17 It is along Fig.16 Cross-sectional view along line XVII-XVII in FIG.

[0049] Fig.18 is a longitudinal sectional view of an HST according to a third embodiment of the present invention, Figure 6 and Fig.16 Corresponding longitudinal section view. DETAILED DESCRIPTION

[0050] Implementation Method 1

[0051] Hereinafter, one embodiment of the HST of the present invention will be described with reference to the drawings.

[0052] Figure 1 , a power transmission diagram of a work vehicle 1 to which a transmission device 10A including an HST 100A according to the present embodiment is applied is shown.

[0053] in addition, Figure 2 , an exploded perspective view of the transmission case 20 in the transmission device 10A and the HST 100A is shown.

[0054] and, Figure 3 to Figure 5 , an exploded perspective view, a cross-sectional top view and a hydraulic circuit diagram of the HST100A are shown respectively.

[0055] like Figure 3 and Figure 4 As shown in the examples, the HST 100A includes a pump shaft 110 which is connected to a drive source 5 (see Figure 1) inputs rotational power at the working place; a pump body 115, supported on the pump shaft 110 in a manner that cannot rotate relative to it; a pump side inclined plate 120, dividing the capacity of the pump body 115; a pump side inclined plate bracket 125A, supporting the back side of the pump side inclined plate 120; a motor shaft 130; a motor body 135, supported on the motor shaft 130 in a manner that cannot rotate relative to it; a motor side inclined plate 140, dividing the capacity of the motor body 135; a motor side inclined plate bracket 145A, supporting the back side of the motor side inclined plate 140; a central portion 150A; a main plate 160A; and a sub-plate 170A.

[0056] The HST 100A of the present embodiment is configured as a tandem type in which the pump body 115 and the motor body 135 are arranged coaxially on one side and the other side in the thickness direction of the central portion 150A, respectively.

[0057] Figure 6 In the figure, it is shown that Figure 4 Cross-sectional view along line VI-VI.

[0058] like Figure 4 and Figure 6 As shown, the pump body 115 includes a pump-side cylinder 116 and a pump-side piston 118 housed in the pump-side cylinder 116 so as to be relatively non-rotatable about the axis and to be able to move forward and backward in the axial direction.

[0059] The pump-side cylinder 116 is supported by the pump shaft 110 in a relatively non-rotatable manner in a state where a base end surface thereof directly or indirectly contacts a first end surface on one side in the thickness direction of the central portion 150A.

[0060] The pump-side swash plate 120 is engaged with the tip of the pump-side piston 118 to divide the amount of advance and retreat of the pump-side piston 118 per rotation of the pump-side cylinder 116 around the axis, that is, the capacity of the pump body 115 .

[0061] In the present embodiment, the pump side swash plate 120 is a movable swash plate that can swing about a swing axis. The amount of advance and retreat of the pump side piston 118 changes according to the swing position of the pump side swash plate 120 about the swing axis, and the volume of the pump body 115 changes.

[0062] The pump-side swash plate support 125A is disposed so as to support the back surface of the pump-side swash plate 120 (the surface on the opposite side in the axial direction to the surface engaging with the pump-side piston 118 ).

[0063] As described above, in the present embodiment, the pump-side swash plate 120 is provided as a movable swash plate that is capable of swinging about a swing axis.

[0064] Therefore, if Figure 6As shown, the pump-side swash plate support 125A has a concave support surface along the swing trajectory of the back side of the pump-side swash plate 120 when the pump-side swash plate 120 swings around the swing axis.

[0065] The pump shaft 110 supports the pump body 115 in an intermediate portion so as to be relatively non-rotatable about the axis while the base end portion and the tip end portion are supported by the central portion 150A and the pump-side swash plate bracket 125A so as to be rotatable about the axis.

[0066] Furthermore, the pump-side swash plate 120 is provided with a through hole that allows the pump shaft 110 to pass therethrough.

[0067] like Figure 4 and Figure 6 As shown, the motor body 135 includes a motor-side cylinder 136 and a motor-side piston 138 housed in the motor-side cylinder 136 so as to be relatively non-rotatable about the axis and to be able to move forward and backward in the axis direction.

[0068] The motor-side cylinder 136 is supported in a relatively non-rotatable manner by the motor shaft 130 disposed coaxially with the pump shaft 110 , with the base end surface directly or indirectly contacting the second end surface on the other side in the thickness direction of the central portion 150A.

[0069] The motor side swash plate 140 is engaged with the tip end of the motor side piston 138 so as to divide the amount of advance and retreat of the motor side piston 138 per rotation of the motor side cylinder 136 around the axis, that is, the capacity of the motor body 135 .

[0070] In the present embodiment, the motor-side slant plate 140 is provided as a fixed slant plate having a fixed inclination angle with respect to the motor shaft 130 , and the volume of the motor body 135 is fixed.

[0071] The motor-side swash plate support 145A is disposed so as to support the rear surface (the surface on the opposite side in the axial direction to the surface engaged with the motor-side piston 138 ) of the motor-side swash plate 140 .

[0072] As described above, in the present embodiment, the motor-side slant plate 140 is provided as a fixed slant plate.

[0073] Therefore, if Figure 6 As shown, the motor side slant plate bracket 145A has an inclined support surface for fixing the motor side slant plate 140 at a predetermined inclination angle.

[0074] The motor shaft 130 is coaxially arranged with the pump shaft 110 , and the motor body 135 is supported in an intermediate portion so as to be non-rotatable relative to the axis while the base end and the tip end are rotatably supported by the central portion 150A and the motor side inclined plate bracket 145A respectively.

[0075] Furthermore, the motor-side slant plate 140 is provided with a through hole that allows the motor shaft 130 to pass therethrough.

[0076] Figure 7 In the figure, it is shown that Figure 4 Cross-sectional view along line VII-VII.

[0077] like Figure 4 and Figure 7 As shown in FIG. 1 and FIG. 2 , a pair of HST hydraulic oil passages 151 for fluidly connecting the pump body 115 and the motor body 135 are formed in the central portion 150A.

[0078] The main plate 160A and the sub-plate 170A are configured to sandwich the central portion 150A, the pump-side swash plate bracket 125A, and the motor-side swash plate bracket 145A by inner surfaces facing each other.

[0079] That is, the main plate 160A is fastened by a fastening member 190 (see FIG. 1 ) such as a bolt, with the inner surface of the main plate 160A abutting against the side surface of the central portion 150A, the pump side inclined plate bracket 125A, and the motor side inclined plate bracket 145A on one side of the width direction perpendicular to the thickness direction (i.e., the axial direction of the pump shaft 110 and the motor shaft 130). Figure 3 ) are connected to these components.

[0080] The sub-plate 170A is arranged opposite to the main plate 160A in a state where the central portion 150A, the pump side inclined plate bracket 125A and the motor side inclined plate bracket 145A are arranged between the inner surface of the sub-plate 170A and the inner surface of the main plate 160A, and the inner surface of the sub-plate 170A is abutted against the side surface of the central portion 150A, the pump side inclined plate bracket 125A and the motor side inclined plate bracket 145A on the other side in the width direction, by a fastening member 191 such as a bolt (see Figure 3 ) are connected to these components.

[0081] like Figure 3 , Figure 4 , Figure 6 and Figure 7As shown in the figures, when observing along the direction relative to the main frame 160A and the sub-plate 170A (i.e., the direction orthogonal to the main frame 160A and the sub-plate 170A), the main frame 160A is provided with a setting space larger than the central portion 150A, the pump side inclined plate bracket 125A and the motor side inclined plate bracket 145A, and an extension area 162 extending outward in the surface direction of the sub-plate 170A.

[0082] According to the HST100A having such a structure, the central portion 150A, the pump-side swash plate bracket 125A, and the motor-side swash plate bracket 145A are doubly supported by the main plate 160A and the sub-plate 170A, so that the support of the components can be stabilized.

[0083] Furthermore, the transmission case 20 to which the HST 100A is mounted is provided with an opening 22 (see FIG. 1 ) which is smaller than the extension area 162 of the main plate 160A and larger than the installation space of the central portion 150A, the pump side inclined plate bracket 125A, the motor side inclined plate bracket 145A, and the sub-plate 170A. Figure 2 ), the HST100A can be attached to and detached from the transmission case 20 without disassembling the HST100A.

[0084] Therefore, it is possible to facilitate the maintenance work and parts replacement work of the HST100A.

[0085] In detail, Figure 1 and Figure 2 As shown, the transmission device 10A includes: the transmission 20; an input side transmission shaft 30 supported by the transmission 20 so as to be rotatable around the axis in a state of being operatively connected to the drive source 5; an input side transmission gear 32 supported by the input side transmission shaft 30 in a manner that cannot rotate relative to the transmission 20; an output side transmission shaft 35 supported by the transmission 20 so as to be rotatable around the axis; an output side transmission gear 37 supported by the output side transmission shaft 35 in a manner that cannot rotate relative to the transmission 20; and the HST100A. The input side transmission gear 32 and the output side transmission gear 37 are arranged in a state of being separated in the axial direction at the front half of the transmission 20.

[0086] The HST 100A is detachable from the transmission case 20 , and is configured such that, when mounted to the transmission case 20 , the pump shaft 110 is operatively connected to the input-side transmission shaft 30 , and the motor shaft 130 is operatively connected to the output-side transmission shaft 35 .

[0087] In detail, Figure 1 to Figure 4As shown in FIGS. 1 and 1 , the HST 100A further includes a pump-side transmission gear 112 supported by the pump shaft 110 in a relatively non-rotatable manner, and a motor-side transmission gear 132 supported by the motor shaft 130 in a relatively non-rotatable manner.

[0088] In this embodiment, the pump side transmission gear 112 is supported on a portion of the pump shaft 110 extending from the pump side inclined plate bracket 125A to the opposite side of the pump body 120, and the motor side transmission gear 132 is supported on a portion of the motor shaft 130 extending from the motor side inclined plate bracket 145A to the opposite side of the motor body 135.

[0089] like Figure 2 As shown, the gearbox 20 has a peripheral wall 21 and the opening 22 arranged on the peripheral wall 21 at its front half.

[0090] The opening 22 is set to have a size that allows components other than the main board 160A in the HST 100A to be inserted therethrough when the HST 100A is in an assembled state.

[0091] That is, the opening 22 is configured to be larger than the installation space of the central portion 150A, the pump-side swash plate bracket 125A, the motor-side swash plate bracket 145A, and the sub-plate 170A, and smaller than the extended region 162 of the main plate 160A.

[0092] In the present embodiment, the opening 22 is provided on a side surface of the peripheral wall 21 which is located laterally with respect to a state in which the transmission case 20 is mounted on the work vehicle 1 .

[0093] Instead of this, the opening 22 may be provided on the upper surface or the lower surface of the peripheral wall 21 .

[0094] like Figure 2 and Figure 3 As shown, a fastening hole 163 through which a fastening member such as a bolt can be inserted is formed in the extended area 162 of the main plate 160A.

[0095] The extended region 162 abuts against the outer surface of the peripheral wall 21 of the transmission 20 when the components of the HST 100A other than the main plate 160A are accommodated in the transmission 20 via the opening 22 , and is detachably connected to the outer surface via fastening components such as bolts inserted through the fastening holes 163 .

[0096] Furthermore, the pump-side transmission gear 112 and the motor-side transmission gear 132 are configured to mesh with the input-side transmission gear 32 and the output-side transmission gear 37 , respectively, in a state where the extended region 162 of the main plate 160A is connected to the outer surface of the peripheral wall 21 of the transmission case 20 .

[0097] like Figure 3 and Figure 4 As shown, in this embodiment, the inner surfaces of the main plate 160A and the sub-plate 170A are provided with central portion recesses 165 and 175 into which the central portion 150A is inserted so as to be unable to move in the thickness direction.

[0098] By having this structure, it is possible to achieve support stabilization of the HST pre-assembly formed by assembling the central portion 150A, the pump shaft 110, the pump body 115, the pump side inclined plate 120, the pump side inclined plate bracket 125A, the motor shaft 130, the motor body 135, the motor side inclined plate 140 and the motor side inclined plate bracket 145A.

[0099] In addition, in the present embodiment, the center portion recesses 165 and 175 are provided on both the main plate 160A and the sub-plate 170A, but may be provided on only one of them.

[0100] Moreover, if Figure 3 and Figure 4 As shown, in this embodiment, pump side recesses 166, 176 for the pump side inclined plate bracket 125A to be snapped into and motor side recesses 167, 177 for the motor side inclined plate bracket 145A to be snapped into are provided on the inner surfaces of the main plate 160A and the sub-plate 170A.

[0101] The pump-side recesses 166 and 176 and the motor-side recesses 167 and 177 are configured to prevent the pump-side swash plate bracket 125A and the motor-side swash plate bracket 145A from moving away from the central portion 150A in the thickness direction (the axial direction of the pump shaft 110 and the motor shaft 130 ).

[0102] like Figure 4 As shown, in the present embodiment, the pump-side recessed portions 166 , 176 include stepped portions 166 a , 176 a that engage with the end surface of the pump-side swash plate bracket 125A on the side opposite to the central portion 150A.

[0103] The motor-side recessed portions 167 , 177 include stepped portions 167 a , 177 a that engage with the end surface of the motor-side swash plate bracket 145A on the side opposite to the central portion 150A.

[0104] By providing this structure, it is possible to further stabilize the support of the HST pre-assembly.

[0105] Instead, the pump-side recessed portions 166 and 176 and the motor-side recessed portions 167 and 177 may be configured to prevent the pump-side swash plate bracket 125A and the motor-side swash plate bracket 145A from moving in the direction approaching the central portion 150A in the thickness direction.

[0106] That is, the pump side recesses 166, 176 may be configured to have a step portion that engages with an end surface of the pump side inclined plate bracket 125A on a side close to the central portion 150A, and the motor side recesses 167, 177 may be configured to have a step portion that engages with an end surface of the motor side inclined plate bracket 145A on a side close to the central portion 150A.

[0107] In this embodiment, if Figure 7 As shown, the central portion recesses 165 and 175 have step portions 165a, 165b, 175a, and 175b that are engaged with the lower surface and the upper surface of the central portion 150A.

[0108] Figure 8 and Fig. 9 In the figure, the Figure 4 Cross-sectional views along line VIII-VIII and line IX-IX.

[0109] like Figure 8 As shown, in the present embodiment, the pump-side recessed portions 166 and 176 have step portions 166 b, 176 b, 166 c, and 176 c that are engaged with the lower surface and the upper surface of the pump-side swash plate bracket 125A.

[0110] Likewise, Fig. 9 As shown, the motor-side recessed portions 167 and 177 have step portions 167 b, 177 b, 167 c, and 177 c that are engaged with the lower surface and the upper surface of the motor-side swash plate bracket 145A.

[0111] According to this configuration, it is possible to further stabilize the support of the HST pre-assembly.

[0112] In addition, in the present embodiment, the central portion recesses 165, 175 have step portions 165a, 175a engaged with the lower surface of the central portion 150A and step portions 165b, 175b engaged with the upper surface, but this can also be replaced by a deformation having only a step portion engaged with one of the lower surface and the upper surface.

[0113] In addition, the pump side recesses 166, 176 and the motor side recesses 167, 177 have step portions 166b, 176b, 167b, 177b that engage with the lower surface of the corresponding inclined plate bracket and step portions 166c, 176c, 167c, 177c that engage with the upper surface, but instead of this, they can be deformed to have only a step portion that engages with one of the lower surface and the upper surface.

[0114] In addition, in the present embodiment, the pump side recesses 166 and 176 are provided on both the main frame 160A and the sub-frame 170A, and the motor side recesses 167 and 177 are provided on the two frames 160A and 170A, but the pump side recess may be provided only on one of the main frame 160A and the sub-frame 170A, and / or the motor side recess may be provided only on one of the main frame 160A and the sub-frame 170A.

[0115] like Figure 4 and Figure 5 As shown, the HST 100A of the present embodiment further includes a hydraulic servo mechanism 200 that generates a force for swinging a movable swash plate (the pump-side swash plate 120 in the present embodiment).

[0116] In this embodiment, the hydraulic servo mechanism 200 is disposed on the main board 160A.

[0117] Fig.10 and Fig.11 In the figure, the following are shown: Figure 4 Cross-sectional views of line XX and line XI-XI.

[0118] like Figure 4 , Figure 5 , Fig.10 and Fig.11As shown, the hydraulic servo mechanism 200 comprises: a push piston 210, which is accommodated in the main plate 160A so as to reciprocate in a direction (hereinafter referred to as a push direction) orthogonal to the axis of a hydraulic body (in this embodiment, the pump body 115) whose capacity changes through the movable inclined plate (in this embodiment, the pump side inclined plate 120) and the swing axis, and is connected to the movable inclined plate via a connecting rod 205 in such a way that the movable inclined plate swings around the swing axis by moving along the pushing direction; a first working oil chamber 215 (1), 215 (2) so as to be able to use the supplied pressure oil to push the push piston 210 to one side of the pushing direction, respectively. and the other side is pushed in the main board 160A; the switching slide valve 220 can selectively select the first working position, the second working position and the closed position. In the first working position, the hydraulic source is fluidly connected to the first working oil chamber 215 (1) and the second working oil chamber 215 (2) is discharged and the pressure oil from the hydraulic source is supplied to the first working oil chamber 215 (1). In the second working position, the hydraulic source is fluidly connected to the second working oil chamber 215 (2) and the first working oil chamber 215 (1) is discharged and the pressure oil from the hydraulic source is supplied to the second working oil chamber 215 (2). In the closed position, the first working oil chamber and the second working oil chamber 2 15(1), 215(2) are closed; the operating piston 230 is housed in the main board 160A so as to be reciprocatingly movable when connected to the switching slide valve 220 via the connecting pin 225, and the switching slide valve 220 can be selected to be located in the first operating position, the closed position and the second operating position, respectively; the first operating oil chamber and the second operating oil chamber 235(1), 235(2) are formed on the main board 160A in such a way that the operating piston 230 can be pushed toward the first operating position and the second operating position, respectively, by the supplied pressure oil; and the operating valve 250 can be selectively selected to be in the first position, the second position and the closed position, and in the first operating position, the second operating position can be selected to be located in the second operating position, respectively. In the 1st position, the hydraulic source is fluidly connected to the first operating oil chamber 235 (1) and the second operating oil chamber 235 (2) is discharged, and the pressure oil from the hydraulic source is supplied to the first operating oil chamber 235 (1) to position the operating piston 230 in the first operating position. In the second position, the hydraulic source is fluidly connected to the second operating oil chamber 235 (2) and the first operating oil chamber is discharged, and the pressure oil from the hydraulic source is supplied to the second operating oil chamber 235 (2) to position the operating piston 230 in the second operating position. In the closed position, the first operating oil chamber and the second operating oil chamber 235 (1), 235 (2) are closed to position the operating piston 230 in the holding position.

[0119] In this embodiment, the switching slide valve 220 is received in an axial hole formed in the pushing piston 210 , and the reciprocating direction (switching direction) of the switching slide valve is set to be the same as the pushing direction of the reciprocating motion of the pushing piston.

[0120] In the present embodiment, the operation valve 250 is provided as a solenoid valve whose operation is controlled by a control device provided in the work vehicle 1 .

[0121] like Figure 5 and Fig.10 As shown, in the present embodiment, the first operating oil chamber 235 (1) is provided with a first spring 240 (1) for urging the operating piston 230 toward the first operating position, and the second operating oil chamber 235 (2) is provided with a second spring 240 (2) for urging the operating piston 230 toward the second operating position.

[0122] The urging force of the first and second springs 240 ( 1 ) and 240 ( 2 ) is set so that the operating piston 230 is located at the holding position when the pressure oil does not act on both the first and second operating oil chambers 235 ( 1 ) and 235 ( 2 ).

[0123] The HST 100A further includes a manual operation mechanism 260 for manually moving the switching slide valve 220 .

[0124] In detail, Figure 4 As shown, the direction of reciprocating motion of the operating piston 230 (operating direction) and the direction of reciprocating motion of the switching slide valve (switching direction) are set to be parallel to each other, and the connecting pin 225 is engaged with the switching slide valve 220 at the base end and engaged with the operating piston 230 at the top end in such a manner that the switching slide valve 220 moves along the switching direction in accordance with the movement of the operating piston 230 along the operating direction.

[0125] In this embodiment, the manual operating mechanism 260 is disposed on the main board 160A.

[0126] In detail, the manual operating mechanism 260 comprises: an operating shaft 265, which is supported on the main board 160A so as to be rotatable around an axis while being parallel to the connecting pin 225 and with the top end extending outward; and a connecting arm 270, the base end of which is connected to the operating shaft 265 so as to be non-rotatable relative to the axis and the top end of which is connected to the connecting pin 225.

[0127] When the operation shaft 265 is rotated about the axis by human operation, the switching slide valve 220 moves in the switching direction via the connection arm 270 and the connection pin 225 .

[0128] In addition to the scheme of moving the switching slide valve 220 by hydraulic pressure via the operating valve 250 by providing the manual operating mechanism 260 , the scheme of moving the switching slide valve 220 by manual operation of the operating shaft 265 may be provided.

[0129] Therefore, even if one of the control structure for electrically controlling the position of the operating valve 250 and the manual operating mechanism for manually controlling the position of the operating valve 250 fails due to some accident, the position of the operating piston 230 can be controlled by the other.

[0130] Next, the oil circuit in the HST 100A will be described.

[0131] Fig.12 , which is a front view of the HST100A in a state of being assembled to the transmission 20 as viewed from the outside of the transmission 20. Fig.12 In the figure, the cross section is used to represent Figure 2 Part XXII of the .

[0132] in addition, Fig.13 In the figure, it is shown that Fig.12 Cross-sectional view along line XIII-XIII in FIG.

[0133] and, Fig.14 In the figure, it is shown that Figure 4 Cross-sectional view along line XIV-XIV in FIG.

[0134] like Figure 2 , Figure 5 and Fig.13 As shown, the main board 160A is provided with: an oil supply circuit 310, one end of which is opened on the outer surface to form an inlet port 310P; a filling overflow valve 315 for setting the hydraulic pressure of the oil supply circuit 310; a lubricating oil circuit 320 for receiving the overflow oil of the filling overflow valve 315; and a lubricating overflow valve 325 for setting the hydraulic pressure of the lubricating oil circuit 320.

[0135] like Figure 5 As shown, in the present embodiment, pressure oil is supplied to the inlet port 310P via a pipe 305 from an auxiliary pump 9 driven by a driving source of the work vehicle 1 .

[0136] like Figure 5 and Fig.14 As shown, the downstream side of the pressure oil flow direction of the supply oil passage 310 is branched into a charging supply oil passage 311 and a servo supply oil passage 312 .

[0137] like Figure 7As shown, the downstream side of the pressure oil flow direction of the charging supply oil passage 311 opens at the contact surface with the central portion 150A to form a main plate side charging port 311P.

[0138] In this embodiment, as described above, the main board 160A is provided with a central portion recess 165 into which the central portion 150A is inserted so as to be immovable in the thickness direction, and the main board side filling port 311P is provided on the bottom surface of the central portion recess 165 .

[0139] like Figure 5 and Figure 7 As shown, in addition to the pair of HST working oil passages 151, a filling oil passage 153 having one end opened on the outer surface to form a filling port 153P on the central portion side is provided in the central portion 150A.

[0140] The downstream side of the pressure oil flow direction of the charging oil passage 153 branches into two directions, and is fluidically connected to the pair of HST working oil passages 151 via the check valve 154 .

[0141] like Figure 5 As shown, in this embodiment, the check valve 154 is provided with a high-pressure relief function, and when one HST working oil circuit 151 becomes abnormally high pressure, the pressure oil of the one HST working oil circuit 151 is caused to overflow to the other HST working oil circuit 151 .

[0142] The servo supply oil passage 312 is configured to supply pressure oil to the operation valve 250 and the switching spool valve 220 .

[0143] like Figure 8 and Fig. 9 As shown, the transmission case 20 is configured to store oil in the front half, and the oil level OL is set at a low level so that when the HST100A is assembled to the transmission case 20, it will not become a rotation resistance of the pump body 115 and the motor body 135. Figure 5 As shown in FIG. 1 , the lubricating oil passage 320 includes a pump-side lubricating oil passage 321 and a motor-side lubricating oil passage 322 to perform forced lubrication on the HST 100A.

[0144] like Figure 4 , Figure 5 and Figure 8 As shown in FIG. 1 , the pump side lubricating oil passage 321 is connected to predetermined lubricating locations such as bearings and piston shoes via the lubricating oil passage 126 formed in the pump side swash plate bracket 125A and the axial hole 111 formed in the pump shaft 110 .

[0145] like Figure 4 , Figure 5 and Fig. 9 As shown in the figures, the motor side lubricating oil passage 322 is connected to predetermined lubricating parts such as bearings and piston shoes via the lubricating oil passage 146 formed in the motor side inclined plate bracket 145A and the axial hole 131 formed in the motor shaft 130.

[0146] also, Figure 7 Reference numeral 330 in the figure is a pressure oil extraction oil passage which is connected to the HST working oil passage 151 at one end and opens at the outer surface of the main plate 160A to form an extraction port for measuring the pressure of the HST working oil passage 151. Fig.12 Reference numeral 332 in the figure is a plug for closing the removal port.

[0147] Here, the transmission device 10A will be described.

[0148] like Figure 1 As shown, in this embodiment, the transmission device 10A has: a multi-speed transmission mechanism 40, which performs multi-speed transmission on the rotational power of the output side transmission shaft 35; a differential mechanism 45, which differentially transmits the output of the multi-speed transmission mechanism 40 to a pair of left and right main drive axles 80; a running brake mechanism 50, which adds braking force to the main drive axles 80; and a power extraction mechanism 55 for auxiliary drive wheels, which can output the output of the multi-speed transmission mechanism 40 to the auxiliary drive wheels.

[0149] The speed change device 10A also has: a PTO shaft 90 capable of outputting rotational power to an external machine such as a working device; a PTO transmission shaft 92 operatively connected to the input side transmission shaft 30 ; and a PTO braking mechanism 94 and a PTO speed change mechanism 96 inserted in the PTO transmission path from the input side transmission shaft 30 to the PTO shaft 90 .

[0150] Of course, the HST 100A can also be applied to other speed change devices 10B.

[0151] Fig.15 , a power transmission diagram of a work vehicle 1 to which another transmission device 10B including the HST 100A is applied is shown.

[0152] In addition, in the drawings, the same reference numerals are given to the same components as those in the present embodiment.

[0153] The transmission device 10B includes a planetary gear mechanism 60 , a forward / reverse travel switching mechanism 65 , and a multi-speed change mechanism 70 instead of the multi-speed change mechanism 40 .

[0154] The planetary gear mechanism 60 has three planetary elements including a sun gear 61, a planetary carrier 62 and an internal gear 63, and is configured to synthesize the rotational power of the HST100A input via the output side transmission shaft 35 and the rotational power of the driving source 5 input via the input side transmission shaft 30, and output the synthesized rotational power.

[0155] In the illustrated configuration, the rotational power of the HST 100A is input to the sun gear 61 via the output-side transmission shaft 35 , the rotational power of the drive source 5 is input to the internal gear 63 via the input-side transmission shaft 30 , and the combined rotational power is output from the carrier 62 .

[0156] Implementation Method 2

[0157] Hereinafter, other embodiments of the HST of the present invention will be described with reference to the drawings.

[0158] Fig.16 , a longitudinal sectional view showing a state where the HST 100B of the present embodiment is assembled to the transmission 20 as viewed from the inner side of the transmission 20 is shown.

[0159] in addition, Fig.17 In the figure, it is shown that Fig.16 Cross-sectional view along line XVII-XVII in FIG.

[0160] In addition, in the figure, the same figure marks are attached to the same components as those in the above-mentioned embodiment 1, and their description is omitted appropriately.

[0161] The HST 100B of the present embodiment is different from the HST 100A of the first embodiment in that the pump body 115 and the motor body 135 are arranged in parallel with each other on one side in the thickness direction of the central portion 150B.

[0162] Specifically, the HST100B comprises: a central portion 150B; a pump side inclined plate bracket 125B; a motor side inclined plate bracket 145B; a main plate 160B and a sub-plate 170B, wherein the central portion 150B, the pump side inclined plate bracket 125B and the motor side inclined plate bracket 145B are clamped in a state where both the pump side inclined plate bracket 125B and the motor side inclined plate bracket 145B are arranged on one side in the thickness direction of the central portion 150B; the pump shaft 110 is supported by the central portion 150B and the pump side inclined plate bracket 125B. The pump body 115 is supported on the pump shaft 110 in a manner that it cannot rotate relative to the pump shaft 110; the pump side inclined plate 120 is supported on the back by the pump side inclined plate bracket 125B; the motor shaft 130 is supported by the central part 150B and the motor side inclined plate bracket 145B in a state parallel to the pump shaft 110 so as to be able to rotate freely around the axis; the motor body 135 is supported on the motor shaft 130 in a manner that it cannot rotate relative to the motor shaft 130; and the motor side inclined plate 140 is supported on the back by the motor side inclined plate bracket 145B.

[0163] like Fig.16 and Fig.17 As shown, in the present embodiment, the pump-side swash plate bracket 125B and the motor-side swash plate bracket 145B are formed by a single common swash plate bracket 180 .

[0164] That is, the HST 100B includes the common swash plate bracket 180 integrally including a portion functioning as the pump-side swash plate bracket 125B and a portion functioning as the motor-side swash plate bracket 145B, and the main plate and the sub-plate are configured to sandwich the central portion and the common swash plate bracket.

[0165] Similar to the main board 160A in the first embodiment, when viewed in the direction relative to the main board 160B and the sub-board 170B, the main board 160B is provided with a setting space larger than the central portion 150B, the pump side inclined plate bracket 125B and the motor side inclined plate bracket 145B (i.e., the common inclined plate bracket 180) and an extension area 162 extending outward in the surface direction of the sub-board 170B.

[0166] On the inner surfaces of the main plate 160B and the sub-plate 170B, recessed portions for the common inclined plate bracket 180 and the central portion 150B to be inserted are provided to prevent the HST pre-assembly from moving in the axial direction.

[0167] In this embodiment, if Fig.16 and Fig.17As shown, on the inner surface of the main board 160B, as the snap-in recess, there are provided: a recess 350 for the inclined plate bracket, formed with a step portion 350a that is snap-fitted to the end surface of the common inclined plate bracket 180 on the opposite side to the central portion 150B; and a recess 355 for the central portion, formed with a step portion 355a that is snap-fitted to the end surface of the central portion 150B on the opposite side to the common inclined plate bracket 180.

[0168] In addition, on the inner surface of the sub-plate 170B, as the snap-in recess, there are provided: a recess 360 for an inclined plate bracket, which is formed with a step portion 360a that is snap-fitted to the end surface of the common inclined plate bracket 180 on the side opposite to the central portion 150B; and a recess 365 for a central portion, which is formed with a step portion 365a that is snap-fitted to the end surface of the central portion 150B on the side opposite to the common inclined plate bracket 180.

[0169] By providing this structure, it is possible to stabilize the support of the HST pre-assembly by the main plate 160B and the sub-plate 170B.

[0170] Implementation 3

[0171] Hereinafter, other embodiments of the HST of the present invention will be described with reference to the drawings.

[0172] Fig.18 , a longitudinal sectional view showing a state where the HST 100C of the present embodiment is assembled to the transmission 20 as viewed from the inner side of the transmission 20 is shown.

[0173] In addition, in the figure, the same figure marks are attached to the same components as those in the above-mentioned Embodiments 1 and 2, and their descriptions are appropriately omitted.

[0174] The HST100C of this embodiment is similar to the HST100A of the first embodiment in that the pump body 115 and the motor body 135 are respectively arranged on one side and the other side of the thickness direction of the central portion 150C, but is different from the HST100A in that the axial positions of the pump body 115 and the motor body 130 are different.

[0175] That is, in the HST100C of this embodiment, the pump body 115 is arranged on one side of the central portion 150C in the thickness direction, and on the other hand, the motor body 135 is arranged on the other side of the thickness direction of the central portion 150C with its axis parallel to the axis of the pump body 115 and located at a different position.

[0176] Specifically, if Fig.18As shown, the HST100C comprises: a central portion 150C; a pump side inclined plate bracket 125C; a motor side inclined plate bracket 145C; a main plate 160C and a sub-plate 170C, wherein the central portion 150C, the pump side inclined plate bracket 125C and the motor side inclined plate bracket 145C are clamped in a state where the pump side inclined plate bracket 125C and the motor side inclined plate bracket 145C are respectively arranged on one side and the other side in the thickness direction of the central portion 150B; the pump shaft 110 is supported by the central portion 150C and the pump side inclined plate bracket 125C to be around the axis The pump body 115 is supported on the pump shaft 110 in a manner that it cannot rotate relative to the pump shaft 110; the pump side inclined plate 120 is supported on the back by the pump side inclined plate bracket 125C; the motor shaft 130 is supported by the central part 150C and the motor side inclined plate bracket 145C in a manner that is parallel to the pump shaft 110 and has a different axial position so as to be able to rotate freely around the axis; the motor body 135 is supported on the motor shaft 130 in a manner that it cannot rotate relative to the motor shaft 130; and the motor side inclined plate 140 is supported on the back by the motor side inclined plate bracket 145B.

[0177] Similar to the main board 160A of the first embodiment and the main board 160B of the second embodiment, when viewed in the direction relative to the main board 160C and the sub-board 170C, the main board 160C is provided with a setting space larger than the central portion 150C, the pump side inclined plate bracket 125C and the motor side inclined plate bracket 145C, and an extension area 162 extending outward in the surface direction of the sub-board 170C.

[0178] The inner surfaces of the main plate 160C and the sub-plate 170C are also provided with recessed portions for the pump side inclined plate bracket 125C, the central portion 150C and the motor side inclined plate bracket 145C to be inserted into, so as to prevent the HST pre-assembly from moving in the axial direction.

[0179] The engaging recess for the central portion 150C is formed to have a step portion that engages with the end surfaces on one side and the other side in the thickness direction of the central portion 150C.

[0180] The engaging recessed portion for the pump-side swash plate bracket 125C is formed to have a step portion that engages with the end surface of the pump-side swash plate bracket 125C on the side opposite to the central portion 150C.

[0181] The engaging recessed portion for the motor-side swash plate bracket 145C is formed to have a step portion that engages with an end surface of the motor-side swash plate bracket 145C on the opposite side to the central portion 150C.

[0182] Description of Reference Numerals

[0183] 10A~10C Speed ​​change device

[0184] 20 Gearbox

[0185] 21 Wall

[0186] 22 Opening

[0187] 30 Input side drive shaft

[0188] 32 Input side transmission gear

[0189] 35 Output side transmission shaft

[0190] 37 Output side transmission gear

[0191] 100A~100C HST

[0192] 110 Pump shaft

[0193] 112 Pump side transmission gear

[0194] 115 Pump body

[0195] 120 Pump side ramp

[0196] 125A~125C Pump side inclined plate bracket

[0197] 130 Motor shaft

[0198] 132 Motor side transmission gear

[0199] 135 Motor body

[0200] 140 Motor side ramp

[0201] 145A~145C Motor side inclined plate bracket

[0202] 150A~150C Central part

[0203] 160A~160C Mainboard

[0204] 162 Extended Area

[0205] 165 Concave for central part

[0206] 166 Pump side recess

[0207] 167 Motor side recess

[0208] 170A~170C Sub-board

[0209] 175 Recessed part for central part

[0210] 176 Pump side recess

[0211] 177 Motor side recess

[0212] 180 Common inclined plate bracket

[0213] 200 Hydraulic servo mechanism

[0214] 205 Connecting rod

[0215] 210 Push piston

[0216] 215(1), 215(2) 1st working oil chamber and 2nd working oil chamber

[0217] 220 Switching slide valve

[0218] 225 Connecting pin

[0219] 230 Operating piston

[0220] 235(1), 235(2) 1st operating oil chamber and 2nd operating oil chamber

[0221] 250 Operating valve

[0222] 260 Manual operating mechanism

[0223] 350, 355, 360, 365 snap into recess

Claims

1. A hydrostatic continuously variable transmission mechanism, It is characterized in that have: A pump shaft; a pump body supported on the pump shaft in a manner that cannot rotate relative to the pump shaft; a pump side inclined plate that divides the capacity of the pump body; a pump side inclined plate bracket that supports the back side of the pump side inclined plate; a motor shaft; a motor body supported on the motor shaft in a manner that cannot rotate relative to the motor shaft; a motor side inclined plate that divides the capacity of the motor body; a motor side inclined plate bracket, supporting the back side of the motor side inclined plate; a central portion, directly or indirectly in sliding contact with the pump body and the motor body and forming an oil path for fluidly connecting the two; and a main plate and a sub-plate, using inner surfaces facing each other to clamp the central portion, the pump side inclined plate bracket and the motor side inclined plate bracket, The main plate is provided with an extension region extending outward in a surface direction from the central portion, installation spaces for the pump-side sloping plate bracket and the motor-side sloping plate bracket, and the sub-plate when viewed in a direction in which the main plate and the sub-plate are opposed to each other.

2. The hydrostatic continuously variable transmission mechanism according to claim 1, It is characterized in that The pump body and the motor body are coaxially arranged on one side and the other side in the thickness direction of the central portion.

3. The hydrostatic continuously variable transmission mechanism according to claim 1, It is characterized in that The pump body is disposed on one side of the central portion in the thickness direction, and the motor body is disposed on the other side of the central portion in the thickness direction so that the axis thereof is parallel to the axis of the pump body at a different position.

4. The hydrostatic continuously variable transmission mechanism according to claim 2 or 3, It is characterized in that A pump side recess for the pump side inclined plate bracket to be inserted into and a motor side recess for the motor side inclined plate bracket to be inserted into are provided on the inner surface of at least one of the main plate and the sub-plate. The pump side recess and the motor side recess are configured to prevent the pump side swash plate bracket and the motor side swash plate bracket from moving away from the central portion in the thickness direction or to prevent the pump side swash plate bracket and the motor side swash plate bracket from moving toward the central portion in the thickness direction.

5. The hydrostatic continuously variable transmission mechanism according to any one of claims 2 to 4, It is characterized in that A central portion recess into which the central portion is inserted so as to be immovable in the thickness direction is provided on the inner surface of at least one of the main plate and the sub-plate.

6. The hydrostatic continuously variable transmission mechanism according to claim 1, It is characterized in that The pump body and the motor body are arranged on one side in the thickness direction of the central portion in a state of being parallel to each other.

7. The hydrostatic continuously variable transmission mechanism according to claim 6, It is characterized in that A common swash plate bracket integrally including the pump-side swash plate bracket and the motor-side swash plate bracket is provided.

8. The hydrostatic continuously variable transmission mechanism according to claim 7, It is characterized in that On the inner surface of at least one of the main plate and the sub-plate, there is a recessed portion for the common inclined plate bracket and at least one of the central portion to be inserted, so as to prevent the static hydraulic continuously variable transmission mechanism formed by the central portion, the pump shaft, the pump body, the pump side inclined plate, the motor shaft, the motor body, the motor side inclined plate and the common inclined plate bracket from being pre-assembled and moving in the axial direction of the pump shaft.

9. The hydrostatic continuously variable transmission mechanism according to any one of claims 1 to 8, It is characterized in that At least one of the pump-side swash plate bracket and the motor-side swash plate bracket supports the back surface of the corresponding swash plate so that the corresponding swash plate can swing around the swing axis. The main plate is provided with a hydraulic servo mechanism that causes a movable swash plate, which is supported so as to be swivelable about a swivel axis, to swivel about a corresponding swivel axis, among the pump-side swash plate and the motor-side swash plate.

10. The hydrostatic continuously variable transmission mechanism according to claim 9, It is characterized in that The hydraulic servo mechanism comprises: a pushing piston, which is accommodated in the main board and can reciprocate in the pushing direction, and is connected to the movable inclined plate via a connecting rod in a manner that the movable inclined plate is swung around a swing axis in accordance with the movement along the pushing direction; a first working oil chamber and a second working oil chamber are formed on the main board in a manner that the pushing piston can be pushed to one side and the other side of the pushing direction by the supplied pressure oil; a switching slide valve, which switches the supply and discharge of pressure oil to the first working oil chamber and the second working oil chamber according to the switching direction position; an operating piston, which is accommodated in the main board and can reciprocate in the operating direction parallel to the switching direction, and is connected to the switching slide valve via a connecting pin; the first operating oil chamber and the second operating oil chamber are formed on the main board in a manner that the operating piston can be pushed to one side and the other side of the operating direction by the supplied pressure oil; and an operating valve, which switches the supply and discharge of pressure oil to the first operating oil chamber and the second operating oil chamber, The main board is provided with a manual operation mechanism capable of manually changing the switching direction position of the switching slide valve.

11. A speed change device that changes the speed of rotational power input from a driving source. It is characterized in that have: a gearbox; an input-side transmission shaft supported on the gearbox so as to be rotatable about an axis in a state of being operatively connected to the drive source; an input-side transmission gear supported on the input-side transmission shaft in the gearbox so as to be non-rotatable relative to the input-side transmission shaft; an output-side transmission shaft supported on the transmission case so as to be rotatable about an axis; an output-side transmission gear supported on the output-side transmission shaft in the transmission case so as to be non-rotatable relative to the output-side transmission shaft; and a hydrostatic continuously variable transmission mechanism, The hydrostatic continuously variable transmission mechanism comprises: a pump shaft; a pump body supported on the pump shaft in a relatively non-rotatable manner; a pump side inclined plate dividing the capacity of the pump body; a pump side inclined plate bracket supporting the back side of the pump side inclined plate and provided with a through hole for the pump shaft to pass through; a pump side transmission gear supported on a portion of the pump shaft extending from the pump side inclined plate bracket to the opposite side of the pump body in a relatively non-rotatable manner; a motor shaft; a motor body supported on the motor shaft in a relatively non-rotatable manner; a motor side inclined plate dividing the capacity of the motor body; a motor side inclined plate bracket, supporting the back side of the motor side inclined plate and provided with a through hole for the motor shaft to pass through; a motor side transmission gear, supported in a relatively non-rotatable manner on a portion of the motor shaft extending from the motor side inclined plate bracket to the opposite side of the motor body; a central portion, formed with an oil passage for fluidly connecting the pump body and the motor body; and a main plate and a sub-plate, using inner surfaces facing each other to clamp the central portion, the pump side inclined plate bracket and the motor side inclined plate bracket, The transmission case has a peripheral wall and an opening provided in the peripheral wall, wherein the opening is set to a size that allows components other than the main plate in the hydrostatic continuously variable transmission mechanism to be inserted when the hydrostatic continuously variable transmission mechanism is assembled. The main plate can be attached to and detached from the outer surface of the peripheral wall of the transmission case in a state where the components of the hydrostatic continuously variable transmission mechanism other than the main plate are accommodated in the transmission case through the opening. The pump-side transmission gear and the motor-side transmission gear respectively mesh with the input-side transmission gear and the output-side transmission gear in a state where the main plate is mounted on the outer surface of the peripheral wall of the transmission case.

12. The speed change device according to claim 11, It is characterized in that The main board is provided with an oil supply passage having one end opened on the outer surface to form an inlet for introducing oil for replenishing the working oil of the hydrostatic continuously variable transmission mechanism. A portion of the oil introduced into the oil supply passage is introduced into the axial hole of the pump shaft and the axial hole of the motor shaft via the pump-side inclined plate bracket and the motor-side inclined plate bracket, respectively, and is supplied to the lubricated part via the axial hole.

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