continuously variable transmission

Abstract

continuously variable transmission (10) an input shaft (20), an output shaft (30), an intermediate shaft (40), a variator gearbox (50), a hydrostatic transmission (60), a housing (70) and a bearing plate (80), wherein the housing (70) at least partially encloses all shafts and components, and has an input side for power introduction and an output side for power output, wherein the continuously variable transmission (10) has an installation position which is provided for during operation, wherein the input shaft (20) is connected to the intermediate shaft (40) via one or more tooth engagements by means of gears, wherein the variator transmission (50) is arranged on the intermediate shaft (40), wherein the intermediate shaft (40) is connected to the output shaft (30) via one or more tooth engagements, wherein the hydrostatic transmission (60) is arranged geometrically parallel to the variator transmission (50) in a lateral view in the installed position, and the power flow can be divided between the hydrostatic transmission (60) and the variator transmission (50), wherein the output shaft (30) is offset horizontally and vertically to the input shaft (20) in the installed position, viewed in the axial direction, wherein the housing (70) is one-piece and open on one side, and the components within the continuously variable transmission (10) are held in the housing (70) by the bearing plate (80) in the assembled state, wherein the housing (70) and / or the bearing plate (80) have flat surfaces on the outer sides which are designed to fasten module components on an outer side of the continuously variable transmission (10).

Description

[0001] The invention is a continuously variable transmission with a hydraulic component for use in vehicles.

[0002] Continuously variable transmissions with hydraulic components are used in agricultural vehicles. Their operation allows the drive power to be distributed across a hydraulic and a mechanical branch of the transmission, along with continuously variable shifting of the respective gears or gear ranges. Agriculture places different driving demands on the drive. On the one hand, driving on roads is a prerequisite for transport work with low to medium torque. On the other hand, working fields with the help of attachments with medium to high torque is necessary. Hydraulic continuously variable transmissions have proven advantageous in this field. Maintenance and robustness are advantageous in these areas, along with a long service life.

[0003] Hydraulic continuously variable transmissions generally feature a hydrostatic drive, a shift range, and a mechanism for switching between forward and reverse operation. To increase the efficiency of such a transmission, the number of meshing points between the gears used is typically minimized.

[0004] The installation space of the transmission is limited by the components connected to it, particularly the overall length in the vehicle direction of such transmissions. At the same time, the overall height, the vertical extension, is also limited by the axle positions within the transmission relative to the input and output shafts, so that any arbitrary reduction of the transmission space is not possible.

[0005] The present invention solves the problems mentioned by providing a continuously variable transmission with a smaller installation space. Furthermore, the invention minimizes gear meshes.

[0006] The continuously variable transmission according to the invention comprises an input shaft, an output shaft, an intermediate shaft, a variator transmission, a hydrostatic transmission, a housing, and a bearing plate, wherein the housing at least partially encloses all shafts and components and has an input side for power introduction and an output side for power output, wherein the continuously variable transmission has an installation position which is provided for during operation, wherein the input shaft is connected to the intermediate shaft via one or more tooth engagements by means of gears, wherein the variator transmission is arranged on the intermediate shaft, wherein the intermediate shaft is connected to the output shaft via one or more tooth engagements, wherein the hydrostatic transmission is arranged geometrically parallel to the variator transmission in a side view in the installation position, and the power flow can be divided between the hydrostatic transmission and the variator transmission,wherein the output shaft, viewed in the axial direction, is offset horizontally and vertically relative to the input shaft in the installed position, wherein the housing is integral and open on one side, and the components within the continuously variable transmission are held in the housing by the bearing plate in the assembled state, wherein the housing and / or the bearing plate have flat surfaces on the input and / or output side which are designed to fasten module components to an outer side of the continuously variable transmission.

[0007] The input shaft transfers the drive power from the input shaft to the continuously variable transmission. The drive power is transmitted to connected modules via the intermediate shaft and the output shaft. The variator transmission is able to provide different speed ranges for driving the vehicle using gear couplings and clutches. The hydrostatic transmission within the continuously variable transmission represents a power branch through which part of the power is transferred parallel to the variator transmission. The invention thus enables a compact design of a continuously variable transmission with a shortened overall length. The offset and the geometric parallel installation position of the shafts, i.e. the installation position on the same section in the longitudinal direction, saves additional installation space and can therefore be used for additional modules, such as a lubricant supply or all-wheel drive.

[0008] In a further development, the output shaft (30) has a forward-reverse clutch (90).

[0009] By providing the forward-reverse clutch on the output shaft, further installation space can be saved in the length of the gearbox.

[0010] In a further embodiment of the invention, the output shaft has a forward clutch and the intermediate shaft has a reverse clutch.

[0011] The arrangement allows for space-saving accommodation of the reverse clutch and the associated intermediate gear for reversing the direction of rotation.

[0012] In a further development, the output shaft has a reverse clutch and the intermediate shaft has a forward clutch.

[0013] The arrangement allows for space-saving accommodation of the reverse clutch and the associated intermediate gear for reversing the direction of rotation.

[0014] In a further embodiment of the invention, the variator transmission is an epicyclic gear transmission and / or a superposition gear transmission.

[0015] The epicyclic gear design allows for a compact installation space while simultaneously providing a high gear ratio spread. The epicyclic gear design is highly efficient due to the minimal required gear mesh. The superposition gear design allows the hydrostatic transmission and its power output to be used as an additional input for the variator transmission.

[0016] In a further development, the continuously variable transmission has a secondary shaft. The secondary shaft can be used for the arrangement of the hydrostatic transmission.

[0017] In a further embodiment of the invention, the intermediate shaft is connected to an input of the hydrostatic transmission via one or two tooth engagements, and an output of the hydrostatic transmission is connected to an input of the variator transmission by means of a tooth engagement.

[0018] Minimizing the necessary gear meshing improves the efficiency of the continuously variable transmission and its impact on noise and driving comfort.

[0019] In a further development, the output shaft is shorter than the input shaft and is arranged offset in the axial direction in the installation position to the input shaft.

[0020] Shortening the output shaft reduces the installation space in the longitudinal direction of the continuously variable transmission. Offsetting the output shaft means that all gears on the input and output shafts are located on a vertical plane, either with a tooth flank or with the center of the tooth width. This arrangement enables a uniform dimension for supporting the gears and the shaft in the bearing plate. The bearing plate can thus be designed in a flat shape without any protrusions. This, in turn, leads to material savings, weight reduction, and a robust seal between the housing and the bearing plate, as a complicated sealing geometry is avoided.

[0021] According to one embodiment, the hydrostatic transmission (60) is arranged in an installation position in the lowest position under all other shafts.

[0022] The placement of the hydrostatic transmission at the lowest position in the installation position allows for a space layout in which the input shaft and output shaft are positioned higher and simultaneously offset from each other in both horizontal and vertical directions. This arrangement allows for a significant reduction in the required installation space lengthwise, as the individual components are arranged parallel.

[0023] In a further embodiment of the invention, the arranged gears are located on one side inside the housing in the installation position in the longitudinal direction with the tooth flank on the same plane, or with the center of the respective tooth width on a common plane which is perpendicular to the shafts.

[0024] The transverse alignment of all gears on one side of the transmission offers the possibility of creating a common bearing in the housing's bearing plate. This arrangement allows for a flat end for the bearing plate, so that it also has a continuous plane. This is particularly advantageous for connecting additional modules to the continuously variable transmission.

[0025] In a further development, the input shaft is arranged in a side view in the installation position at the top position above all other shafts.

[0026] The top-mounted arrangement, together with the hydrostatic transmission in the bottom position, saves installation space and allows for a compact arrangement of the hydrostatic transmission and variator transmission in a parallel design. The overall length of the continuously variable transmission is reduced, and less material is used overall.

[0027] In a further embodiment of the invention, the bearing shield is designed to be open or closed.

[0028] In the open design, the bearing shield can have openings for the passage of operating fluids, such as lubricant. Openings can also be provided for hydraulic lines, electrical cables, or even mechanical shafts or connections. This design allows for the direct connection of additional functional modules to the housing or bearing shield of the continuously variable transmission.

[0029] Further embodiments of the invention are described with reference to the figures. Fig. 1 a diagram of the continuously variable transmission; Fig. 2 a transverse view of the installation position with the positions of the shafts in the continuously variable transmission.

[0030] The continuously variable transmission 10 has an input shaft 20, which is connected to the intermediate shaft 40 via at least one toothed engagement. The intermediate shaft 40 is connected on the one hand to an input of the variator transmission 50, and on the other hand, via further toothed engagements, to the auxiliary shaft 100, which in turn is connected to the input of the hydrostatic transmission 60. On an output side of the hydrostatic transmission 60, the input to an input of the variator transmission 50 takes place via a further toothed engagement. The variator transmission 50 is connected to an output via toothed engagement with the forward-reverse unit 90 and its clutch. Downstream of the forward-reverse unit 90, the power is delivered to connected modules and to the drive system.

[0031] The input shaft 20 can have a toothing on one side, which translates the power to the intermediate shaft 40. The translation from the intermediate to the auxiliary shaft 40, 100 can be carried out with a reversal of the direction of rotation, as in Fig. 1. The hydrostatic transmission 60 represents one power branch, the variator transmission 50 another. The power branches are summed in the variator transmission 50, and the sum is transmitted to the forward-reverse unit 90 via a gearing. The forward-reverse unit 90 switches between forward and reverse via a clutch.

[0032] The variator transmission 50 can be designed as an epicyclic transmission, whereby the output torque and the output speed are determined by means of superposition, i.e. by means of the speed and torque differences occurring between the two power branches.

[0033] Fig. Figure 1 shows a so-called stick diagram, which illustrates the functional relationships between the shafts and elements. Thus, the local arrangement of the shafts is not shown. The hydrostatic transmission 60 is provided at the lowest position in the invention, so that the output shaft 30 is arranged in a central position. Fig. 1 does not contradict the arrangement, but describes the functioning of the continuously variable transmission 10 in a two-dimensional representation.

[0034] Fig. 1 shows that the gearing of the input shaft 20 and the intermediate shaft 40 are arranged in one plane.

[0035] Fig.Figure 2 describes an embodiment of the continuously variable transmission 10 with a shaft arrangement in a longitudinal view in the axial direction. The housing 70 at least partially encloses the individual components of the continuously variable transmission 10. The housing is covered or closed by the bearing plate 80. The bearing plate 80 can have openings through which operating fluids are introduced or mechanical connections are established. The bearing plate 80 can also be arranged in a completely sealed configuration, so that only mechanical connections are realized by means of shafts, whereby the shafts are sealed.

[0036] The input shaft 20 is in the uppermost position in the installed position. This arrangement allows the distance between the input and output shafts 20, 30 to be increased, allowing all components to be arranged on the respective shaft sections. The intermediate shaft 40 is arranged horizontally and vertically offset below. The intermediate shaft 40 includes the variator transmission 50 and is connected to the input shaft 20 by a toothed mesh.

[0037] The output shaft 30 is arranged horizontally and vertically offset from the input shaft 20 and the intermediate shaft 40 below the intermediate shaft 40. This arrangement has the advantage that the installation space for the variator transmission 50 and the hydrostatic transmission 60 can be optimally arranged in the housing 70. Furthermore, it is possible to arrange both transmissions 50 and 60 parallel to each other.

[0038] The hydrostatic transmission 60 is located in the lowest position in the installation position of the continuously variable transmission 10. This arrangement allows for optimal use of installation space and easy maintenance access within the housing 70.

[0039] The power path of the continuously variable transmission 10 is routed via the input shaft 20 and is split on the intermediate shaft 40 via one or more meshing engagements between the hydrostatic transmission 60 and the variator transmission 50. After the hydrostatic transmission 60, the power path is recombined in the variator transmission 50, with the variator transmission 50 being designed as a superposition transmission. The power path is then routed to the output shaft 30 via the forward / reverse clutch 90.

[0040] The continuously variable transmission 10 presented here enables a compact design, short in terms of installation space along the shaft, which allows for advantageous integration into the vehicle drivetrain. The invention expands the application possibilities and enables a modular drivetrain design. Additional modules and components can be connected to the flat outer surfaces of the continuously variable transmission 10 in a standardized design with reduced effort. The continuously variable transmission 10 allows scaling across additional model series and standardization of the connection modules.

Claims

[1] Continuously variable transmission (10) comprising an input shaft (20), an output shaft (30), an intermediate shaft (40), a variator gearbox (50), a hydrostatic transmission (60), a housing (70) and a bearing plate (80), wherein the housing (70) at least partially encloses all shafts and components, and has an input side for power introduction and an output side for power output, wherein the continuously variable transmission (10) has an installation position which is provided for during operation, wherein the input shaft (20) is connected to the intermediate shaft (40) via one or more tooth engagements by means of gears, wherein the variator transmission (50) is arranged on the intermediate shaft (40), wherein the intermediate shaft (40) is connected to the output shaft (30) via one or more tooth engagements, wherein the hydrostatic transmission (60) is arranged geometrically parallel to the variator transmission (50) in a lateral view in the installed position, and the power flow can be divided between the hydrostatic transmission (60) and the variator transmission (50), wherein the output shaft (30) is offset horizontally and vertically to the input shaft (20) in the installed position, viewed in the axial direction, wherein the housing (70) is one-piece and open on one side, and the components within the continuously variable transmission (10) are held in the housing (70) by the bearing plate (80) in the assembled state, wherein the housing (70) and / or the bearing plate (80) have flat surfaces on the outer sides which are designed to fasten module components on an outer side of the continuously variable transmission (10). [2] Continuously variable transmission (10) according to claim 1, characterized by that the output shaft (30) has a forward-reverse clutch (90). [3] Continuously variable transmission (10) according to claim 1, characterized by that the output shaft (30) has a forward clutch and the intermediate shaft (40) has a reverse clutch. [4] Continuously variable transmission (10) according to claim 1, characterized by that the output shaft (30) has a reverse clutch and the intermediate shaft (40) has a forward clutch. [5] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the variator transmission (50) is an epicyclic transmission and / or a superposition transmission. [6] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the continuously variable transmission (10) has a secondary shaft. [7] Continuously variable transmission (10) according to one of the preceding claims, characterized bythat the intermediate shaft (40) is connected to an input of a hydrostatic transmission (60) via one or two tooth engagements, an output of the hydrostatic transmission (60) is connected to an input of the variator transmission (60) by means of a tooth engagement. [8] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the output shaft (30) is shorter than the input shaft (20) and is arranged offset in the axial direction in the installation position to the input shaft (20). [9] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the hydrostatic transmission (60) is arranged in an installation position in the lowest position below all other shafts. [10] Continuously variable transmission (10) according to one of the preceding claims, characterized bythat the arranged gears on one side inside the housing (70) in the installed position lie with the tooth flank on the same plane, or lie with the center of the respective tooth width on a common plane which is perpendicular to the shafts. [11] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the input shaft (20) is arranged in a side view in the installed position in the uppermost position above all other shafts. [12] Continuously variable transmission (10) according to one of the preceding claims, characterized by that the bearing shield (80) is open or closed.

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