The invention concerns a radial-piston hydraulic motor equipment.

In the prior art, a number of solutions of axial-piston hydraulic motors are known, in which a high torque is achieved with high speeds of rotation only. In the present patent application, attempts have been made to find out an assembly of a hydraulic motor apparatus of a novel type in which a high torque is achieved at low speeds of rotation.

According to the invention, as the hydraulic motor, an axial-piston hydraulic motor is used, which comprises a cam ring placed in a stationary position, the press wheels of the piston in the piston mechanism being fitted to move along the cams in the cam ring. Into the piston space in the piston mechanism, a pressure medium, preferably hydraulic fluid, is passed through a system of medium ducts placed in a distributor that is in a stationary position, so that the pistons present in the power stage move with a force towards the wave-shaped cam face of the cam ring and produce rotation of the rotor part of the piston mechanism. The rotor part itself operates as a constructional part that forms the cylinder spaces for the pistons that are fitted radially along the circumference. Those pistons that are not in the power stage transfer the fluid out of the piston space back towards the pump. In the cylinder spaces of the pistons that are in the idling stage, the medium, preferably hydraulic fluid, has a pressure lower than in the power stage. The pressure is, however, such that it also keeps the cam wheels of the pistons that are in the idling stage pressed against the wave-shaped face of the cam ring. Depending on the number of piston parts that are subjected to the working pressure, it is possible to regulate the speed of rotation of the hydraulic motor and the output torque of the hydraulic motor, which torque depends on said speed of rotation. The pressure of the medium, preferably hydraulic fluid, is passed to the pistons through a distributor valve, into

which distributor valve the pressure is passed from a pump. By reversing the direction of circulation of the fluid pumping in the pump, it is possible to reverse the sense of rotation of the hydraulic motor. The sense of rotation can also be reversed by using a directional valve and by passing the pressure fluid either into the inlet port or into the outlet port. By means of the distributor valve constructed in connec¬ tion with the hydraulic motor, the pressurized medium is passed, depending on the position of the distributor valve, either into three outlets or into six outlets of the distributor, in which case, optionally, the pressurized medium, preferably hydraulic fluid, is passed simultaneously either to two pistons present in the power stage or, at a low speed of rotation and a higher torque of the motor, to four pistons present in the power stage.

The changing of speed takes place so that, at a higher speed, every other outlet in the distributor is closed. In one position of the valve, the hydraulic fluid is made to flow simultaneously into two groups of sets of ducts, each of said groups of sets of ducts consisting of three separate outlets. In a corresponding way, the pistons present in the non-power stage communicate, at the same time, through the distributor, with the space of pressure-free fluid, and in this way the pumping of fluid produced by the pistons is permitted as a return flow towards the pump and back into the hydraulic-fluid tank.

Thus, according to the invention, the pressurized medium is made to flow into one or several groups of pistons at the same time, depending on the desired speed of rotation. The solution of equipment comprises a cam disc, whose inside is wave- shaped and which is stationary in relation to the casing frame of the hydraulic motor, the pistons of the hydraulic motor being fitted to move along the wave-shaped face of the cam disc while the pistons comprise wheels or equivalent at their ends, said wheels or equivalent being fitted to move in compliance with the face form of the cam disc while pressed by means of the pressure medium against the face of the cam disc. Thus, the pressurized medium forces the rotor part, which operates as the cylinder frame of the device, and the shaft connected to same to revolve.

According to the invention, at one end, the shaft comprises a sun wheel connected with the shaft, which sun wheel is fitted to rotate the planetary wheels, which are mounted in a stationary position on the planetary support, and which sun wheel is further fitted to rotate the rim wheel, which is a part of the revolving casing of the device.

In a first preferred embodiment of the device the shaft comprises a coupling com¬ posed of two parts, in which coupling a spring equipment is fitted between two axially displaceable press frames. By means of the spring device, the press member of the press frame is kept in a position in which the press member presses the lamellae connected with the shaft of the lamellar coupling into engagement with the lamellae connected with the body of the sun wheel. Thus, in said position of the coupling, the sun wheel is rotated directly by means of the shaft and, further, the planetary wheels are rotated by the intermediate of the teeth on the sun wheel, and the rim wheel of the construction is rotated by the intermediate of the planetary wheels, which rim wheel is a part of the casing frame of the device. In this position of operation of the device, pressurized medium is also passed to the other coupling, said other coupling being in the open position and rotation of the rim wheel being permitted.

When the first coupling is kept in the open position and the second coupling in the closed position, the rotation is passed from the shaft directly to the casing frame of the equipment, in which case the shaft directly rotates the other devices related to the casing frame.

According to the invention, in a second preferred embodiment of the device, the equipment comprises a sun wheel of the planetary gear, which sun wheel is con¬ nected with the shaft and rotates the planetary wheels and, via them, further the rim wheel, which is a part of the revolving casing frame of the equipment. In this embodiment of the invention, the invention comprises a coupling provided with one press member, said coupling being opened by means of the pressure of a medium, preferably the pressure of hydraulic fluid, against the spring force of a spring, which

spring force, in the idling position, keeps the coupling closed and the lamellae of the lamellar support, which are connected with the shaft, in engagement with the lamellae connected with the support frame of the planetary wheels. Since the support frame of the planetary wheels is of fixed construction, in said stage of operation of the equipment the shaft is locked in relation to the frame. In a corresponding way, the rim wheel of the device, which is a part of the casing frame of the device, is, thus, also locked. Thus, the coupling arrangement also operates as a brake of the device.

The radial-piston hydraulic motor equipment in accordance with the invention is mainly characterized in that the equipment comprises a sun wheel driven by the shaft as well as planetary wheels, which are fitted to be rotated by the sun wheel, and that the equipment comprises a rim wheel, which is driven by the planetary wheels either directly or indirectly and which rim wheel is a part of the outside casing frame of the equipment, which casing frame can be fitted to revolve.

In the following, the invention will be described with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying draw¬ ings, the invention being, however, not supposed to be confined to said embodiments alone.

Figures 1 A and IB show the first position of regulation - low speed - of the radial- piston hydraulic motor in accordance with the invention. Fig. 1A shows the setting of the valve, and Fig. IB shows the distribution of the working pressure into the pistons in the power stage.

Figures 2 A and 2B show the second position of regulation of the hydraulic motor, with which position a higher speed is attained. Fig. 2 A shows the position of the valve spindle. Fig. 2B shows the distribution of the working pressure into the pistons at the power stage through the distributor.

Figure 3 shows a hydraulic diagram for a valve construction that is suitable for

three-speed control and in which solution of equipment such a cam disc is used in which every second cam is of different height.

Figure 4 shows a first preferred embodiment of a radial-piston hydraulic motor equipment in accordance with the invention.

Figure 5 shows a second preferred embodiment of a radial-piston hydraulic motor equipment in accordance with the invention.

Figure 6 shows the area A in Fig. 4, and what is shown is an embodiment of the invention in which the support 28 is connected through a toothed coupling to rotate the sun wheel.

Figure 7 shows the area B in Fig. 5, and what is shown is an embodiment of the invention in which the sun wheel is mounted freely with a glide fitting around the shaft and the movement from the shaft to the sun wheel is transferred through a toothed coupling between the coupling-disc fastening frame and the sun wheel.

Figure 8 shows an embodiment of the invention in which there are second planetary wheels.

Figure 9 shows an equipment in which the frame connected with the planetary wheels is in engagement with the rim wheel and with an intermediate wheel.

Figure 10 shows an equipment in which the sun wheel is a floating construction and is placed at the end of the drive shaft.

Figure 11 shows a construction in which the drive from the shaft can be transferred through a coupling directly to the rim wheel.

Figs. 1A...1B show a radial-piston hydraulic motor related to the equipment in accordance with the invention. Figs. 1B,2B correspond to sectional views along the

line I-I in Fig. 4 and also in Fig. 5. The radial-piston hydraulic motor is in itself known, but it will be described in the following in view of permitting an understand¬ ing of the whole of the invention. Fig. 1A shows the distributor- valve 13, into which, at the low speed of the device, the pressurized medium is passed through the inlet duct A. The valve comprises a spindle K and therein spindle portions K _j and K ₂ of larger diameter, which are interconnected by a spindle portion K ₃ of smaller diameter. The control pressure to the end of the valve spindles is passed along the control-pressure ducts C _j and C ₂ . In the position shown in Fig. 1A, the pressurized medium is passed into the duct A and distributed in the valve housing, in the position of operation shown in the figure, into the ducts Ai and A ₂ , from which the pressurized medium is made to flow further into the two duct groups Ai ' and A ₂ ' in the distributor 17. The return flow takes place from the cylinders into which high- pressure medium is not passed, and in the embodiment shown in Fig. 1A the return flow takes place through the ducts B _j ' and B _j . In Fig. IB, the distributor outlets related to the duct A _j are denoted with A , and the distributor outlets related to the duct A ₂ are denoted with A' ₂ , and the distributor outlets related to the duct B _j are denoted with B _j ' .

Fig. IB illustrates the operation corresponding to the valve position shown in Fig. 1A. Each of the pistons 15a** ,15a ₂ ... and 15a ₈ , which are placed in the cylinder spaces 14a ₁ ,14a ₂ ...14a _g in the rotor 14, comprises a wheel 16 or equivalent at its end, which wheel or equivalent is fitted to follow the wave form of the inner face of the cam disc 12. In the embodiment of the invention the cam disc 12 is non-revolv¬ ing, and so is the distributor 17. On the contrary, the rotor 14, which operates as the cylinder frame for the pistons 15, revolves and rotates the shaft 18 connected to the rotor. Fig. IB shows the cylinders that are pressurized with the spindle position shown in Fig. 1A. The pistons in said cylinders operate as working pistons, and the remaining pistons, in whose cylinders the hydraulic-fluid space is indicated by darker shading, are idling cylinders, and in them a pressure is maintained that is just slightly higher than the fluid pressure in the casing outside the pistons, in order that it should be possible to keep the pistons and their rollers 16 in contact with the wave-shaped face of the cam disc 12. The pistons that are in the power stage press

the wheels 16 with a force against the curved cam face on the cam disc, whereby a rotating torque is produced in the rotor 14.

Fig. 2 A shows a position of regulation of the spindle K of the distributor valve 13 in which the control pressure has been passed into the duct C _j and the spindle K has been shifted to the right in the way shown in the figure, the high pressure being distributed through the duct A into the distributor duct system A _j only, while the duct systems A ₂ and B are in the non-pressurized state or at the maximum in a state of slight pressure.

Fig. 2B shows the state of loading of the pistons corresponding to the position of the spindle K of the distributor valve shown in Fig. 2A. The dark shading represents the pressurized pistons, and those outlets of the distributor are shown into which high- pressure hydraulic fluid is not passed from the pump. Thus, in the embodiment of Fig. 2B, two pistons 15aι ,15a ₄ only are in the power stage at the same time.

In the state of regulation shown in Figs. 2A,2B, a higher speed of rotation of the shaft 18 is obtained than with the regulation shown in Figs. 1A and IB. In the regulation of Figs. 2A,2B, there are two pistons in the power stroke at the same time, whereas in the case of Figs. 1A and IB there were four pistons in the power stroke at the same time.

Fig. 3 shows a hydraulic diagram of an arrangement of equipment in which every other cam 12aι ,12a ₃ ,12a ₅ in the cam disc 12 is of a height different from the height of the remaining cams 12a ₂ ,12a ₄ ,12a ₆ ... Thus, in the hydraulic diagram shown in the figure, the valve has three different blocks. When the middle block valve has been switched on, the feed pressure is distributed in the distributor two openings clockwise, in which case a cam of different height is taken to use. The speed that is attained is higher than the speed attained in the position of regulation shown in Figs. 1 A, IB but lower than the speed that is attained in the position of regulation shown in Figs. 2 A and 2B.

Fig. 4 shows a first preferred embodiment of the radial-piston hydraulic motor equipment in accordance with the invention. The radial-piston hydraulic motor equipment 10 in accordance with the invention comprises a casing 11- of the hydrau¬ lic motor, with which casing a cam disc 12 is connected, which is in a stationary, non-revolving position and which comprises a wave-shaped inside cam shape 12'. The cam disc comprises a number of cams 12a _{1 ;} 12a ₂ ...

According to the invention, the casing frame 11 comprises a distributor valve 13 that has been formed into the casing, the pressurized fluid being distributed in the desired way into the distributor 17 by displacing the spindle K of said valve 13 by means of the control pressure. The equipment comprises a revolving rotor 14, which operates as a cylinder frame for a number of radial pistons 15aι ,15a ₂ ...15a ₈ , each of which pistons comprises a roller 16a ₁ ,16a ₂ ...16a ₈ or equivalent placed at the end of the piston and pressed against the cam disc. When the working pressure is passed through the distributor valve 13 into the distributor 17, which distributor is in a stationary, non-revolving position, the pressurized medium is distributed from the outlet of the system of ducts in the distributor into the cylinder frame 14 of the rotor and through its system of ducts D further into the cylinder spaces 14aι ,14a ₂ ...14a ₈ in the cylinder frame of the rotor, in which cylinder spaces the pistons 15aι ,15a ₂ ...15a ₈ are placed. The rotor 14 is connected by means of grooves E or, for example, a key, non-re volvingly to the shaft 18, whereby, when the pistons are pressed with the force of the pressure of the hydraulic fluid against the cam shape 12a ₁ ,12a ₂ ... of the cam disc, the rotor 14 and the shaft 18 attached to it by means of the grooves E are forced to revolve.

In Fig. 4, the dotted areas represent the system of ducts A _j and A ₂ , into which the pressurized medium is passed in the embodiment shown in the figure and which corresponds to the low speed in Figs. 1A and IB. From the piston 15, away from its cylinder space, the return flow of the hydraulic fluid takes place. In the system of ducts B** ' shown in the figure, a lower pressure is present than in the working pistons, to which the pressure is passed in the situation of regulation of Fig. 4 through the systems of ducts A _j and A . In the embodiment of the figure, the return

pressure is somewhat higher than the pressure present in the casing space F outside the pistons. In such a case, the pistons can be kept in contact with the wave face of the cam disc 12 also in the case of the pistons that are not subjected to the working pressure.

The equipment comprises an end disc 20, which includes the pressure-medium ducts through which the pressure medium is passed to the couplings so as to control the couplings. Thus, the end disc 20 includes the medium ducts 21a and 21b. The shaft 18 is fitted to revolve on support of the bearings G _j and G ₂ .

Fig. 4 shows the first, preferred embodiment of the invention, which comprises a first coupling 22. Around the shaft 18, a first press frame 23 and a second press frame 24 are fitted as freely revolving, a spring device 25, preferably cup springs, being fitted in the space defined by said frames in their interior. By means of grooves 27 or, for example, a key, a fastening frame 26 for the coupling discs 30a is attached to the shaft 18 in a stationary position, said frame 26 revolving along with the shaft 18. When grooves are employed, they extend around the shaft 18, and corresponding grooves are provided on the fastening frame 26. Coupling discs 30b are attached to the frame 28 of the sun wheel 29. The coupling discs 30a,30b are fitted conventionally as interlocking one another, and they can be displaced into contact with one another so as to form a friction engagement. The sun wheel 29 and the related frame 28 are fitted around the shaft 18 with a glide fitting.

The planetary wheels 31aι ,31a ₂ ...13a _n are attached and journalled to revolve in a planetary support frame 32 placed in a stationary position.

The rim wheel 34 is a part of the casing 33 of the device, which casing is fitted to revolve and to which casing the driven device, for example a wheel of a vehicle, can be fixed. The casing 33 and the rim wheel 34 which constitutes a part of same are journalled and supported by bearing means 35a,35b, preferably by means of conical roller bearings, on the support frame 32 for the planetary wheels 13a*ι ,13a ₂ .

Further, the equipment comprises a second coupling 36. The coupling discs 37b are connected with the casing frame 33 of the rim wheel, inside the casing frame 33. The coupling discs 37a, which are placed as interlocking the coupling discs 37b, are attached to the fastening frame 38 that is coupled with the shaft 18. The fastening frame 38 is connected to the shaft 18 non-revolvingly by means of grooves 39 or, for example, by means of a key. Thus, the fastening frame 38 revolves along with the shaft 18. The pressurized medium, preferably hydraulic fluid, is passed along the duct 21a from outside the device in a bore placed in the axial direction of the shaft 18 to the first coupling 22 into the fluid space Mi placed between the press frame 23 and the fastening frame 26 for the coupling discs, and, in a corresponding way, the pressurized medium, preferably hydraulic fluid, is passed through the duct 21b into the space M ₂ between the second press frame 24 and the fastening frame 38.

When said spaces between the press frames and the fastening frames are not pressurized, the spring device 25 keeps the couplings 22,36 in the closed positions, and in such a case the shaft 18 is locked in relation to the outside casing 33. When the pressurized medium is introduced along the duct 21a, the coupling 22 is opened and the rotation is transferred from the shaft 18 via the coupling 36 directly to the rotated casing 33.

If the coupling 36 is open and, thus, the pressure medium is passed along the duct 21b into the space M ₂ , and the first coupling 22 is in the closed position, the rotation is transferred from the shaft 18 via the first coupling 22 to the sun- wheel frame 28 and through it to the sun wheel 29, which is provided with teeth 29a. The teeth 29a are operationally connected with the teeth 31a ₁ ',31a ₂ ' on the planetary wheels 31a _j ,31a ..., and, thus, the sun wheel rotates the planetary wheels 31a _{1 ;} 31a ₂ ... , which are further operationally connected, by the intermediate of their teeth, with the teeth 34a on the rim wheel 34. The rim wheel 34 is a part of the casing 33 of the device, which is fitted to revolve. The planetary wheels 31a-i ,31a ₂ ... are connected so that they are fitted as revolving, but in a stationary revolving position, on the planetary-wheel support frame 32. In the embodiment of Fig. 4, if the hydraulic motor 10 comprises three speeds, by means of the connections shown in

Fig. 4, three further speeds are obtained additionally if the rotation is transferred from the shaft 18 through the planetary gear out. The original three speeds are obtained by using the couplings in the way described above and by transferring the movement from the shaft 18 directly to the rotatable outside casing 33.

Fig. 5 shows an embodiment of the invention that is in other respects similar to the embodiment shown in Fig. 4 except that the rotation from the shaft 18 is, always in connection with the operation of the shaft, transferred through the planetary gear to the outside casing. In the embodiment shown in the figure, there is one coupling 220 only, to which the pressure-medium duct 21a is passed along the shaft 18 from the end of the shaft. The equipment comprises a press frame 23, which is fitted to glide around the shaft 18 and which is fitted to be pressed by a spring device 25, preferab¬ ly cup springs, so that the shoulder 23' presses the coupling discs 30a provided on the coupling fastening frame 26 into contact with the coupling discs 30b fitted on the stationary planetary support frame 32. Thus, when pressure medium is not passed into the pressure-medium duct 21a, the spring device 25 keeps the press frame 23 in contact with the package of coupling discs 30a,30b, in which case the coupling is in the closed position and the shaft 18 is locked with the support frame 32 of the planetary wheel. The spring 25 is placed between the press frame 23, which is displaceable in the direction of the central axis X of the shaft 18, and the back-up part 40 of the spring 25 that is placed stationarily on the shaft 18. When pressurized medium is passed along the medium duct 21a into the space M-*. between the press frame 23, which is fitted to glide around the shaft 18, and the coupling-disc 30a fastening frame 26, which is attached to the shaft stationarily by means of grooves e or, for example, by means of a key, the coupling is opened and it is permitted that the rotation is transferred from the shaft 18 via the teeth on the sun wheel 29, which is attached directly to the shaft 18, to the planetary wheels 31a ₁ ,31a ..., which are placed in a stationary position of rotation in the support frame 32 for the planetary wheels, and from which planetary wheels 31a _j ,31a ₂ ... the rotation is transferred further to the rim wheel 34, whose teeth 34a have been formed as a part of the casing 33 of the device, which casing is fitted to revolve. The driven device, such as a wheel of a vehicle, is connected to the casing 33.

Fig. 6 shows the area A in Fig. 4. The embodiment of Fig. 6 is in the other respects fully similar to the embodiment of Fig. 4, except that there is a toothed coupling 41 between the frame 28 and the sun wheel 29. The movement from the shaft 18 through the coupling discs of the coupling 22 is transferred, when the coupling 22 is closed, to the sun- wheel support frame 28 and from it through the separate toothed coupling 41 to the sun wheel 29. The sun wheel 29 is fitted with a free glide fitting around the shaft 18. The coupling 41 comprises a toothing 41a on the support frame 28, which toothing is fitted to surround the toothing 29a on the sun wheel 29. By means of the arrangement mentioned above, the sun wheel 29 is given a certain play, in which case it is possible to transfer the torque uniformly to several planetary wheels 31a ₁ ,31a ₂ ...31a _n at the same time.

Fig. 7 shows the area B in Fig. 5. The embodiment of Fig. 7 is in the other respects fully similar to the embodiment of Fig. 5, except that the sun wheel 29 is fitted with a glide fitting around the shaft 18, and the movement from the shaft 18 is transferred via the coupling-disc fastening frame 26 to the sun wheel 29 through the toothed coupling 42 between the fastening frame 26 and the sun wheel 29. The fastening frame 26 comprises an inner toothing 42a, which is fitted to surround the toothing 29a on the sun wheel 29. Thus, the sun wheel 29 is given a certain play in order that it should be possible to transfer the torque uniformly to several planetary wheels 31a ₁ ,31a ₂ ...31a _n at the same time.

The embodiments shown in Figs. 8 to 11 are sectional views of the equipment limited to the centre line of the drive shaft 18. Since the construction is rotationally symmetric, the other half of the equipment is similar and is, thus, not shown.

Fig. 8 shows a new embodiment of the invention. By means of the construction as shown in Fig. 8, for example, in transfer operation, a transmission ratio of 1.7 is attained, and in working operation a transmission ratio of 9.1. In the way shown in Fig. 8, the power is transferred from the rotation shaft 18 either through the first coupling lOOa _j or through the second coupling 100a ₂ . The medium ducts 21a _j and 21a ₂ in the shaft 18 communicate with the first coupling lOOa _j and with the second

coupling 100a ₂ .

The first coupling lOOa _j comprises a spring lOla _j and a press member 102. The press member 102 comprises a first frame portion 102a _j and a second frame portion 102a , which is shaped as an annular flange and is parallel to the shaft. The coupling construction comprises a common middle frame 103, which is permanently con¬ nected with the shaft 18 by means of locking members, such as cotters 104a _{l 5} 104a ₂ .

The rotation drive is passed to the shaft 18 from the hydraulic-piston motor. The shaft 18 is journalled to revolve on bearing means G _j ,G ₂ , preferably conical roller bearings. The construction of the hydraulic motor is not illustrated separately in Fig. 5 (should read: Fig. 8 - note by the translator), but the construction is similar to that shown in Fig. 4 and on the basis of the preceding illustrations.

The coupling construction further comprises a second press member 105. Between the middle frame 103 and the frame 102a _j there is a medium space N _j , and between the press member 105 and the frame 102a _! there is a second medium space N ₂ . The press members 105,102 have been fitted to move as a single package by means of glide fitting on the shaft 18. The press member 105 is permanently connected to the frame portion 102a ₂ .

The coupling 100a-; comprises the coupling discs 106a ₁ ,106a ₂ ,106a ₃ ;106b ₁ ,106b ₂ , 106b ₃ ... , which are placed as interlocked. The coupling discs 106a ₁ ,106a ₂ ... are connected with the frame portion 29' of the frame 29 of the sun wheel, and, in a corresponding way, the second coupling discs 106b ₁ ,106b ₂ ... , which are placed as interlocked with said first coupling discs, are connected with the coupling frame 107 conventionally, e.g. , by the intermediate of grooves E. The coupling frame 107 is connected to the shaft 18 permanently. In a corresponding way, the second coupling 100a ₂ comprises a coupling frame 108 and the first coupling discs 109a-* ,109a ₂ ... and the second coupling discs 109b _j ,109b ₂ ... , which first and second discs are placed as interlocked. The coupling discs 109a _j ,109a are connected with the coupling frame 108, and the second coupling discs 109b ₁ ,109b ₂ ... are connected

with the intermediate wheel 110, with its frame portion, with the end of the frame portion. The coupling frame 108 is permanently connected with the shaft 18 by means of grooves E or equivalent.

The intermediate wheel 110 comprises a toothing HOa _j in its middle area. The intermediate wheel 110 is an annular cog-wheel placed around the shaft 18, the rotation drive being distributed through said cog-wheel to the rim wheel 34 optional¬ ly either through the first coupling lOOa _j or through the second coupling 100a ₂ .

When the pressure of the medium is introduced into the space N _j , the coupling discs 106a ₁ ,106a ₂ ...;106b ₁ ,106b ₂ ... are pressed against one another against the spring force of the springs 101 a _{1 ;} and, thus, the rotation drive can be transferred from the shaft 18 through the coupling lOOa*, to the frame part 29' of the sun wheel 29 and further to the frame part 29" . The toothing 29a of the sun wheel 29 is in engagement with the toothings on the first planetary wheels 31a _{1 ;} 31a ₂ .

The frame parts 29' and 29" of the sun wheel 29 are interconnected, e.g., by means of a groove joint E. The frame part 29" is placed freely around the shaft 18.

The first planetary wheels 31a ₁ ,31a ₂ ..., which are rotated by the sun wheel 29, have a construction as follows. For example, the planetary wheel 3^ comprises a revolving frame part 310 and therein a shaft 311 journalled by means of a central bearing 312. The shaft 311 is connected with a circumferential, annular frame 313, and it comprises a toothing 313aι . The shaft 311 is placed centrally in the frame part 310 and, thus, the bearings 312 are placed between the shaft 311 and the frame part 310. The toothing 313a** is in engagement with the toothing 110a-; of the intermedi¬ ate wheel 110.

The frame 313 is an annular part, to which all the planetary wheels 31aι ,31a ₂ ... are connected by their shafts 311. Thus, the toothing 313aι is a circular toothed rim, which is fitted around the toothing HOa- of the intermediate wheel 110. Thus, a sort of a groove joint is formed. The toothed rim 31a ₁ ',31a ₂ '... of each planetary wheel

31a _l5 31a ₂ follows both the toothing 29a on the sun wheel 29 and the stationary toothing 32a*L on the support frame 32. Said toothing 32a _j is a circular toothed rim. It is a non-revolving constructional part placed in a stationary position and followed by the planetary wheels 31a _1? 31a ₂ ...

In engagement with the intermediate wheel 110, there are the second planetary wheels 31bι ,31b ₂ ,31b ₃ ... , which are revolving but otherwise in a stationary position. Each planetary wheel comprises a toothing 31b _j ' on its circumference. The construc¬ tion of planetary wheel comprises a shaft 311' and a bearing 312', the frame 310' of the planetary wheel being fitted to revolve on support of the bearings 312'. The shaft 311' is fitted in a stationary, non-revolving position on the planetary support frame 32 that is placed in a stationary position. The wheels 31b*L,31b ₂ ..., a number of such wheels being preferably provided, are, by the intermediate of their toothings 31b ₁ ',31b ₂ ',31b ₃ ', also in engagement with the toothing 34a _j on the rim wheel 34. Thus, by the intermediate of the shaft 18, it is possible to rotate the casing 33 and further, for example, a wheel of a vehicle.

In Fig. 8, the transfer of power in working operation is indicated by the arrows O _j (through the coupling lOOa _j ), and the transfer of rotation drive in transfer operation by the arrows O ₂ (through the coupling 100a ₂ ). The casing 33 is journalled by means of conical roller bearings G ₁₀ ,G ₂₀ on the stationary support frame 32.

Thus, in the construction in accordance with the invention shown in Fig. 8, there are two sets of planetary wheels: the first planetary wheels 31a _j ,31a ₂ ... , which are used when the transfer of power takes place through the coupling lOOa _j ; and the second planetary wheels 31b ₁ ,31b ₂ .... which are used always when the rotation drive arrives at the rim wheel 34.

Fig. 9 shows a second preferred embodiment of the device in accordance with the invention. The construction is in the other respects similar to that shown in Fig. 8, except that the second planetary wheels are missing completely in the solution. In the solution, the frame 313, which is also an annular part and which is connected with

the shafts 311 of the planetary wheels 31a ₁ ,31a ₂ ... , comprises a toothing 313a ₂ , which toothing constitutes the outer circumference of the frame 313 and is oper¬ ationally connected with the toothing 34a _j or with equivalent grooves on the rim wheel 34. The frame 313 additionally comprises a toothing 313a _{1 ;} which is in engagement with the toothing 110a- on the intermediate wheel 110. When the coupling lOOa _j has been switched on, the rotation drive is transferred from the shaft 18 to the planetary wheels 31a _l5 31a ₂ ... and from the frames 310 of the planetary wheels further via the toothing 313a ₂ to the rim wheel 34. The toothing of each planetary wheel 31a _{1 (} 31a ₂ is additionally in contact with the toothed rim 32a _} placed in a stationary position on the stationary planetary support frame 32.

On the other hand, if the movement is transferred from the shaft 18 through the coupling 100a ₂ , the rotation drive is transferred from the shaft 18 to the intermediate wheel 110 and further through the toothings 110a ₁ ,313a ₁ to the circumferential annular frame part 313 and further via the toothing 313a ₂ on its outer circumference to the rim wheel 34.

Fig. 10 shows an embodiment of the invention in which the coupling construction corresponds to the embodiments shown in Figs. 5 and 6 (should read: Figs. 8 and 9 - note by the translator), but in this construction the coupling construction is placed closer to the hydraulic motor. In the construction, there is a separate floating sun wheel 29 at the end of the construction. Also, in this construction, the frame of the sun wheel consists of two parts 29' and 29", which parts are interconnected by means of a groove joint E. The first planetary wheels 31a _j ,31a ₂ ... are connected with the floating sun wheel 29 so that the toothings 31a-ι ,31a ₂ ... of the planetary wheels 31aι ,31a ₂ ... are in engagement with the toothing 29a _j on the sun wheel 29. The planetary wheels are additionally in engagement with the rim wheel 34, with its toothing 34a _j . In each planetary wheel, the shafts 311 of the planetary wheels 31a _! ,31a ₂ ... are connected with the annular circumferential frame 313, which comprises a toothing 313a** , a toothed rim, which is in engagement with the toothed rim HOa _j on the face of the intermediate wheel 110.

In a corresponding way, the toothed rim 110a-: of the intermediate wheel 110 is in engagement with the second planetary wheels 31b _j ,31b ₂ ... by means of their toothings 31bι ',31b ₂ '... Said planetary wheels are additionally in contact with the toothing 34a _j on the rim wheel 34.

In the embodiment of Fig. 10, the frame parts of the couplings 100aι ,100a ₂ are permanently attached to the shaft 18. The coupling construction is similar to that shown in Figs. 5 and 6 (should read: Figs. 8 and 9 - note by the translator). The second planetary wheels 31b _{l 5} 31b ₂ ... are, by the intermediate of their shafts, permanently connected with the support 32, which is placed in a stationary position.

Fig. 11 shows an embodiment of the invention whose coupling construction is similar, e.g. , to the embodiment shown in Fig. 5 (should read: Fig. 8 - note by the translator). The solution comprises a first coupling 100aι and a second coupling 100a ₂ . When the second coupling 100a ₂ has been switched on, the rotation drive is transferred from the shaft 18 directly to the rim wheel 34 via its grooves 34a ₂ . When the first coupling lOOa _j has been switched on, the rotation drive is transferred from the shaft 18 to the sun wheel 29 and from the sun wheel 29 to the planetary wheels 31a _j ,31a ₂ ... The planetary wheels 31aι ,31a ₂ ... are in contact with the toothing 29a _j on the sun wheel 29 and with the stationary toothing 32a _j on the stationary support frame 32. Further, the planetary wheels 31a-. ,31a ₂ comprise a second toothing 31a _j ",31a ₂ " on their frame 310, which second toothing is in contact with the toothing, grooves 34a-: or equivalent on the outside rim wheel 34, either directly or by means of an intermediate ring 200.

Thus, the rotation drive can be transferred from the shaft 18 either directly through the coupling 100a ₂ to the rim wheel 34 or through the coupling lOOa _j to the sun wheel 29, the planetary wheels 31a _j ,31a ₂ ... and further from the planetary wheels to the rim wheel 34.