SE532439C2 - Hydraulic motor - Google Patents

Description

20 25 30 533 4139 and less penetration of moisture and dirt, which increases the service life of the gasket and thus the engine.

When mounting the engine described in the above-mentioned Sauer-Danfoss Tech Note, the drive shaft and bearings are assembled into one unit before being mounted in the motor housing. The inner cups of the roller bearings are pressed onto the shaft in such a way that one inner cup rests against a shoulder on the shaft. A spacer ring is arranged between the outer shells of the roller bearings to secure the distance between the roller bearings when the motor is clamped. This is important, among other things, for the tolerances in the roller bearings. The second inner cup is typically held in place by means of a nut which is chipped on the drive shaft before and / or after the joined unit is pressed into place in the motor housing. It is now also desired for motors of this kind to move the high-pressure gasket from the exposed position, where the shaft projects from the motor housing, to a position between the roller bearings where the deflection of the shaft is smaller. However, the above-mentioned inner shoulder of the motor housing on which the gasket is placed prevents both roller bearings from being inserted into the motor housing from the same end, and thereby the roller bearings accumulating on the shaft prior to mounting in the motor housing.

The invention is intended to provide a solution to the above-mentioned problem. This is achieved by arranging the high-pressure gasket in the spacer ring which is placed between the outer cups of the roller bearings, e.g. in an annular recess in the spacer ring, in such a way that the gasket seals between the spacer ring and the outside of the drive shaft. It is achieved that the gasket is placed between the roller bearings where the deflection of the drive shaft is smaller, and that the roller bearings and the ring can be mounted on the drive shaft before the joined unit is mounted in the motor housing. Where the drive shaft protrudes from the motor housing, an additional gasket calculated for a lower jaw can be arranged to prevent moisture and dirt from penetrating into the first roller bearing, which can otherwise be filled with grease or hypo gear oil. surfaces, an O-ring can be mounted in a recess in the outer surface of the spacer ring, in such a way that the O-ring seals: between this surface and the inside of the motor housing.

The roller bearings are typically mounted on the drive shaft with a press fit. Thus, when the first roller bearing is mounted on the shaft, it should typically be pressed past the area of the drive shaft that later forms the sealing surface for the high pressure pacing. In order to avoid that the sealing surface is damaged in this case, the part of the shaft which after assembly forms the sealing surface can be machined so that it has a smaller radius than the hole in the inner bowl of the first roller bearing. After mounting the motor, the spacer ring should not normally have contact with the drive shaft and will therefore have a larger inner radius than the sealing surface on the shaft. The spacer ring will thus not be centered during the mounting of roller bearings and ring on the drive shaft. In order to achieve centering of the spacer ring and thus of the high-pressure gasket, the spacer ring can have an outer radius corresponding to the radius of the inside of the motor housing. . The centering can alternatively be achieved in that the spacer ring has annular projections which fit into corresponding depressions in the outer cups of one or both roller bearings.

The invention is described in more detail below with reference to the accompanying figures, of which Figure 1 shows an axial section through a hydraulic motor according to the prior art, and of which Figure 2 shows an axial section through a preferred embodiment of the bearing housing of a hydraulic motor according to the invention.

The drive element in the motor (1) in Figure 1 consists of a set of teeth (2) which is clamped between an end cap (3) and a bearing housing (4). The tooth set (2) consists of an outer ring gear (5) with teeth on the inside and an inner gear (6) with teeth on the outside. A number of rollers (7) are stored in the tooth cavity of the ring gear (5) to reduce the friction and increase the tightness between the parts of the tooth set (2). The gears (5) and the gear wheel (6) have different numbers of teeth, whereby the gear wheel (6) can rotate eccentrically in relation to the latter when engaging in the ring gear (5). Thereby a number of chambers (14) are formed which cyclically change volume during the rotation of the gear (6). By pumping liquid under high pressure into the chambers (14) whose volume is increased, and simultaneously allowing the outflow of liquid from the chambers (14) whose volume is reduced, a torque is achieved on the gear wheel (6) relative to the ring gear (5) and thus to the motor housing.

Typically, the gear (6) has one tooth less than the ring gear (5). This achieves that the gear (6) rotates more slowly than the eccentric movement, which increases the torque.

Inside the end cap (3) a channel disc (8), a valve (9) and a balance disc (10) are arranged in order from the tooth set (2). A number of channels (11) in these connect the A-port (12) and B-port (13) of the motor (1) to the chambers (14) in the tooth set (2). The orientation of the duct plate (8) in relation to the ring gear (5) is secured during the mounting of a guide pin (15). The gear (6) causes the valve (9) to rotate via a valve cardan shaft (16). The balance plate (10) is secured against rotation relative to the end cap (3) with a pipe pin (17). The valve (9) cooperates with the duct plate (8) and the balance plate (10) as a commutator for the motor (1) in that its ducts (11) cyclically overlap differently during the rotation of the valve (9). An example of this is 53.2 435 ta is described in U.S. Pat. No. 3,964,842. A curved spring (18) presses the balance disc (10) and thus the valve (9) against the channel disc (8) and thereby ensures that the hydraulic fluid does not deviate along their mutual surfaces. A spacer (19) holds the valve stem shaft (16) in place axially in the direction of the end cap (3). The end cap (3) and the tooth mounting ring (2) are clamped to the bearing housing (4) by means of a number of through bolts (20), and a number of gaskets such as O-rings are arranged at different places in the joints to hold them. seal. The force transmission from the gear wheel (6) to the drive shaft (21) takes place via a propeller shaft (22) which at the ends is provided with teeth which engage with internal teeth on the gear wheel (6) and the drive shaft (21), respectively. The drive shaft (21) is mounted in the bearing housing (4) by means of two oppositely directed, conical roller bearings (23, 24) which are held in place axially by a front cover (25) which is clamped in the bearing housing (4) by means of a number of bolts (26). Each of the roller bearings (23, 24) consists of a number of bearing rollers (27) which are arranged between an inner bowl (28) and an outer bowl (29). When mounting the drive shaft (21), the first roller bearing (23) is pressed down over the drive shaft (21) in such a way that the inner shell (28) of the roller bearing (23) abuts against a shoulder (30) on the drive shaft (21). Then a spacer ring (32) is mounted, after which the second roller bearing (24) is pressed down over the drive shaft (21). Finally, secure the roller bearings (23, 24) with a nut (31) which is screwed onto the drive shaft (21). During and after mounting the second roller bearing (24), the spacer ring (32) secures the distances between the outer cups (29) of the two roller bearings (23, 24). From the tooth set ring (2) a certain amount of hydraulic fluid is diverted which is used to lubricate the bearings in the motor (1). The liquid is supplied via the cavity (33) in the drive shaft (21), in which the cardan shaft (22) is stored, is passed on via a number of drainage channels (34) and the cavity tube around the roller bearings (23, 24) to the drainage connection (35). A gasket (36) prevents the liquid from flowing directly from the cavity (33) to the drain connection (35). A simmer ring (37) prevents the bag from running out between the drive shaft (21) and the front cover (25).

The swimming ring (35) must now be able to seal satisfactorily and to withstand the drainage pressure, which can be relatively high, depending on how the drainage connection (35) is connected to the hydraulic tank. However, depending on the use of the motor (1), the drive shaft (21) may be subjected to radial forces which cause the drive shaft (21) to deflect. These requirements cannot normally be optimally met by one and the same type of gasket, so the service life of the ring (37) is relatively short. Dirt that penetrates between the simmer ring (37) and the drive shaft (21) also contributes to damaging the drive shaft (21) itself, which is why repairing the motor (1) often requires replacement of both the gear ring (37) and the drive shaft (21). Figure 2 shows how the invention can extend the life of the engine (1) by arranging the high-pressure gasket (102) in a position on the drive shaft (21) where the deflection 532 of one of them is smaller. Numbered positions on the med clock with numbers below 100 correspond to the positions in Figure 1.

The shape of the spacer ring (32) is changed so that its outer side abuts against the inner side (103) of the bearing housing (4). Against the inner cups (28) of both roller bearings (23, 24), the spacer ring (32) is provided with annular depressions (100) which prevent contact between the immovable spacer ring (32) and the rotating inner cups (28). In a further recess (101) in the spacer ring (32) is a gasket (102), e.g. in the form of a BAHD type ring from the Freudenberg company. The mounting ring (102) is pressed into the spacer ring (32) during assembly and is otherwise held in place by the overpressure in the motor (1). Since the deflection of the drive shaft (21) here is less than where the drive shaft (21) projects from the bearing housing (4), and when the gasket (102) in this position is less exposed to dirt from outside, the service life of the gasket (102) in the position shown in FIG. The motor (1) shown in Fig. 2 is longer than for the corresponding gasket (37) in the motor (1) shown in Fig. 1.

In order to seal against leakage along the surface (103) between the spacer ring (32) and the bearing housing (4), an O-ring (105) is arranged in an outer annular recess (104) in the spacer ring (32). The first roller bearing (23) and the cavity around it are filled with grease or hypo-gear oil which lubricates the roller bearing (23) and at the same time prevents moisture and dirt from penetrating further into the bearing housing (4).

Where the drive shaft (21) projects from the front cover (25), a gasket (106) in the form of a yarn marrow, a dust seal (107) in the form of a so-called lip seal and a simmer ring (108) are arranged in order from the outside. , tex. of the type BABSL from fi nna Freudenberg. These gaskets and seals (106, 107, 108) serve to hold the grease or oil in place in the cavity around the first roller bearing (23) and to prevent moisture and dirt from penetrating the same cavity.

The sealing ring (102) must, in order to seal satisfactorily, abut against a smooth surface (109). When the bearings (23, 24) are pressed onto the drive shaft (21), scratches can occur in the surface of the drive shaft (21) during assembly. In order to prevent such scratches from occurring on the abutment surface (109) of the simmer ring (102), the surface (109) is machined so that it has a smaller radius than the inner surface of the inner bowl (23) of the inner bearing (23), whereby the roller bearing (23) can avoid (109) during assembly.

The bearing housing (4) and the spacer ring (32) are provided with bevelled edges (110, 1 1 1) which ensure that the spacer ring (32) is centered during assembly in relation to the bearing housing (4) and thus to the drive shaft (21), the best operating conditions for the simmer ring (102) are achieved.

Figure 2 also shows the internal toothing (112) in which the PTO shaft (22) is mounted, as well as a hole (113) in the drive shaft (21) in which a pin can be fitted to secure a crown nut which is used to clamp t. ex. a machine part driven by the motor (1) on the drive shaft (21). E32 435 In addition to the example shown in Figure 2, the invention can be used in other ways. Thus, it is e.g. it is not necessary to arrange the gasket (102) in a recess (101) in the spacer ring (32).

A suitable gasket (102) can e.g. also arranged on the inner surface of the spacer ring (32).

There are also roller bearings (23, 24) having both an outer and an inner spacer ring (32) abutting the outer bearing cup (29) and the inner bearing cup (28), respectively, and where the spacer rings (32) are adapted to secure a certain bias of the roller bearings (23, 24) during axial compression of the bearing package. In this case, the inner spacer ring (32) will rotate with the drive shaft (21) and thus the gasket (102) can be arranged so that it seals between these two spacer rings (32) instead of between the outer spacer ring (32) and the drive shaft (21). ).

Claims (1)

1 0 15 20 25 532 439 Patent claims. Hydraulic motor (1) with a motor housing (4) and a drive shaft (21) mounted in the motor housing (4) by means of two oppositely directed, conical roller bearings (23, 24), each consisting of a number of bearing rollers (27) arranged between an inner bowl (28) and an outer bowl (29), the outer shells (29) of which are kept at a distance from each other by a first spacer ring (32), characterized in that a first gasket (102) is arranged on such that it seals between the first spacer ring (32) and a bearing surface (109) on the drive shaft (21). . Hydraulic motor according to claim 1, characterized in that a second gasket (105) is arranged in such a way that it seals between the first spacer ring (32) and the motor housing (4). . Hydraulic motor according to Claim 1 or 2, characterized in that the abutment surface (109) has a smaller radius than the inner surface of at least one of the inner cups (28) of the two bearings (23, 24). . Hydraulic motor according to one of Claims 1 to 3, characterized in that a third gasket (106, 107, 108) is arranged so that it seals between the drive shaft (21) and the motor housing (4) where the drive shaft projects from the motor housing ( 4). . Hydraulic motor according to one of Claims 1 to 4, characterized in! in that the abutment surface (109) rests on a second spacer ring arranged on the drive shaft (21) between the inner shells (28) of the bearings (23, 24) in such a way that the first gasket (102) seals between the first the spacer ring (3 2) and the other spacer ring. . Hydraulic motor according to claim 5, characterized! that a fourth gasket is arranged in such a way that it seals between the second spacer ring and the drive shaft (21).