SE1251112A1 - Control cylinder for a gearbox, a gearbox with such control cylinder, and a vehicle with such a gearbox - Google Patents

Description

“IO 15 20 25 30 which are designed in a cylinder housing. A piston in the control cylinder is mounted against the inside of the cylinder housing by means of annular body parts, which have recesses for seals.

The seals thus absorb a substantial force according to this embodiment. At the same time must the cylinder housing has a considerable length in order to be able to be designed with a sufficient long bearing surface for the annular body parts.

Document US-A-45 93 606 discloses an operating cylinder for a gearbox for a vehicle.

The control cylinder is equipped with an extra piston, which enables a main piston to be engaged. placed in an intermediate position. The main piston is provided on its outside with a circumferential plain bearing, which abuts the inside of the cylinder housing. In order for the main piston to be able to stored against the inside of the cylinder housing, the cylinder housing must have a sufficient length.

SUMMARY OF THE INVENTION Despite known solutions, there is a need to further develop a control cylinder, which has a smaller axial extent than existing control cylinders, so that the space the need for the control cylinder at the gearbox decreases and so that everyone for the gearbox necessary components can be fitted to the gearbox.

The object of the present invention is to provide an operating cylinder for one gearbox with small dimensions.

Another object of the invention is to provide a compact control cylinder for a gearbox with low manufacturing cost.

These objects are achieved with an actuating cylinder for a gearbox of it initially said type, which is characterized by the features set forth in claim 1.

A further object of the invention is to provide a gearbox with a maneuverable ver cylinder with small dimensions.

“IO 15 20 25 30 This object is achieved with a gearbox which comprises an operating cylinder of the initial said type, which is characterized by the features stated in the claim 10.

A further object of the invention is to provide a vehicle with a gearbox with a control cylinder with small dimensions.

This object is achieved with a vehicle which initially comprises a gearbox thereof said kind, which is characterized by the features set forth in claim ll.

Such an actuating cylinder has a smaller axial extent than existing actuators. cylinders, which means that the space requirement for the control cylinder at the gearbox decreases, so that all the components necessary for the gearbox can fit in the gearbox.

Gearboxes for vehicles usually have a number of gear stages, which means fl era control cylinders need to be arranged in the gearbox. Thus, the requirement further increases that each control cylinder has small dimensions. Due to the fact that the can be designed with smaller dimensions also reduces the need for materials, which leads to reduced manufacturing costs of the control cylinder. The gearbox can as whole is compactly constructed when the control cylinder has small dimensions, which leads to reduced weight of the vehicle. This also reduces the vehicle's fuel consumption. ning.

Additional advantages of the invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, as an example, a preferred embodiment of the invention is described. one with reference to the accompanying drawings, in which: Pig. 1 shows a schematic side view of a vehicle with an operating cylinder and a gearbox according to the present invention, “IO 15 20 25 30 Fig. 2 shows a sectional view of the operating cylinder according to a first embodiment of the present invention in a first end position, Fig. 3 shows a sectional view of the operating cylinder according to the first embodiment of the present invention in an intermediate position, Fig. 4 shows a sectional view of the operating cylinder according to the first embodiment of the present invention in a second end position, and Fig. 5 shows a sectional view of the operating cylinder according to a second embodiment of present invention in a first end position.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Fig. 1 shows a schematic side view of a vehicle 1, for example a truck. Vehicle 1 is equipped with an internal combustion engine 2, which is connected to a gearbox 4. The gearbox 4 is connected to the drive wheel 6 of the vehicle 1 via a propeller shaft 8. The gearbox 4 is provided with an actuating cylinder 10, which has the task of actuating one or more gears 12 in gear gearbox 4 in order to change the gearbox through gearbox 4. E fi as gearboxes 4 for Vehicle 1 usually comprises a number of gear stages and requires several control cylinders 10 is arranged in the gearbox 4. The operating cylinder 10 is preferably of the pneumatic type and affected by compressed air. However, other fl uids can be used to control the control cylinder 10, for example hydraulic oil.

The gearbox 4 in a truck often consists of an automatic gearbox 4, which comprises one large number of cooperating components to effect the automatic shifting.

The operating cylinder 10 must therefore be designed as small as possible so that all components shall be fitted to the gearbox 4.

Fig. 2 shows a sectional view of the operating cylinder 10 according to a first embodiment of the present invention. present invention in a first end position. The operating cylinder 10 comprises a cylinder “IO 15 20 25 30 house 14, which is provided with a first and second gable 16 resp. 18 to form one space 20 in which a piston 22 is arranged to be able to be moved axially back and forth.

A piston rod 24 is connected to the piston 22 via a fastening element 26. An opening 28 is arranged in the first end wall 16 through which opening 28 the piston rod 24 is arranged to stretch. The piston rod 24 is provided at its end facing away from the piston 22 with a fastening device 30 for connecting an arm 32, which actuates those present in the gearbox 4 give the gears 12 when shifting.

The piston 22 divides it from the cylinder housing 14, the first end 16 and the second end 18 forming the space 20 in a first and second space 34 resp. 36. A first port 38 communicates with the first space 34 and a second port 40 communicates with the second space 36. Through the first and second ports 38, 40 access and removal a fl uid is moved to surface the piston 22 relative to the cylinder housing 14. The first and the second ports 38, 40 are connected to a pressure source 42 for fl uid via the first and second valves valves 44, 46. The valves 44, 46 are preferably controlled by signals from a control unit 48. To the control unit 48 is also connected to a sensor 50, which is mounted in the second end wall 18 and which senses the position of the piston 22 in the cylinder housing 14. This is achieved by partly a pin 52, which is connected to the piston 22, which pin 52 extends into one elongate recess 54 in the transducer 50. Preferably, the transducer 50 is provided with a not shown coil, which by induction registers where the outer end of the pin 52 is located in relation to the coil. By using the sensor 50 sense was in the elongated In the recess 54 the pin 52 is located, the position of the piston 22 in the cylinder housing 14 can be sued.

A third port 56 is provided in the cylinder housing 14, which third port 56 communicates with ambient atmospheric pressure. The third port 56 is in contact with a third outlet. space 58, which is formed between the piston 22 and the cylinder housing 14 and a first and a second radial seal 60 resp. 62, which are arranged between the piston 22 and the cylinder housing 14.

Radial seals 60, 62 are designed to slide on the piston 22 and the cylinder housing 14 at the axial movement of the piston 22 relative to the cylinder housing 14. The radial seals 60, 62 ensures that pressurized fl uid will not be able to flow between the first, second and third 10 15 20 25 30 spaces 34, 36, 58. The third gate 56 has the task of leveling any underpressure and overpressure to atmospheric pressure in the third space 58.

The first and second radial seals 60, 62 are provided with stiffening elements 64, which are intended to co-operate with a circumferential fl end 68 arranged on the piston 22.

Thus, the radial seals 60, 62 can also act as secondary pistons and transfer the force from the pressurized fl uide on the flange 68 of the piston 22 to thereby exert one on acting axial force of the piston 22.

The piston 22 is provided with an axial bore 70, which is arranged by means of a sliding bearing 72. to abut against a lug 74 arranged on the second end wall 18. The bore 70 has preferably a substantially circular shape with a center axis 76 as substantially coincides with the center axis 78 of the piston 22. Preferably, the lug 74 has a substantially circular shape with a diameter smaller than the diameter of the bore 70. For in the case where both the bore 70 and the lug 74 have a circular shape, the sliding bearing 72 is also substantially circular, so that a stable bearing for the piston 22 is obtained. To the piston 22 shall obtain a stable bearing along its entire stroke, the bore 70 and the lug have 74 has an axial extent equal to or greater than the stroke of the piston 22. The the first end 16 is provided at its opening with a piston rod bearing 80, which together man with a piston rod seal 79 stores and absorbs radial forces between the piston rod a 24 and the first gable 16. The sliding bearing 72 between the piston 22 and the lug 74 thereon the second end 18 together with the piston rod bearing 80 causes piston 22 and piston rod 24 with high stability can be moved back and forth in the cylinder housing 14. Sliding bearing 72 between the piston 22 and the lug 74 on the second end wall 18 also means that the operating The axial width of the lindem 10 can be reduced, which means that the space requirement for the operating cylinder 10 at the gearbox 4 decreases, so that all necessary for the gearbox 4 components can be fitted to the gearbox 4. Due to the fact that the control cylinder l0 can be formed with smaller dimensions also reduces the need for materials, which leads to increased manufacturing costs of the control cylinder l0. Gearbox 4 can as a whole is compactly constructed when the control cylinder l0 has small dimensions, which leads to reduced weight of the vehicle 1. This also reduces the fuel consumption of the vehicle. ning. 10 15 20 25 30 According to the first embodiment of the invention shown in Fig. 2, the sliding bearing 72 is used. arranged in a circumferential recess 82 in the bore 70 of the piston 22. 72 to follow the piston 22 in its reciprocating motion. Preferably it is circumferential recess 82 disposed near an end face 84 of the facing piston 22 from the piston rod 24, which results in an increased stability along the entire stroke of the piston 22.

As mentioned above, the actuating cylinder 10 affects the gears in the gearbox 4 len 12 when changing. Because the shift is performed from one shift step to another with one intermediate neutral position, the piston 22 must be steerable to three positions in the cylinder housing 14, which correspond to a first and a second end position and an intermediate position.

To move the piston 22 from that of the fi g. 2 shows the first end position of one shown in FIG intermediate position is supplied pressurized id uid both the first and second spaces 34, 36 in the cylinder the housing 14 through both the first and second ports 38, 40. Thus, the valves 44, 46 and pressurized fl uid from the pressure source 42 are supplied to the first and second spaces. Coal- vein 22 will then be displaced to the intermediate position shown in Fig. 3. The radial seals 60, 62, which abut against the circumferential fl end 68 of the piston 22, act in part with the the forces on the piston 22, partly sealing against that formed between the radial seals 60, 62 third space 58, so that the pressurized fluide is retained in the first and second tube 34, 36, and can not reach the third space 58 so as not to be able to leave the cylinder housing 14 through the third port 56. Preferably, the inside of the cylinder housing 14 is provided with a circumferential projection 86, which forms abutment surfaces 88 for radial sealing. 60, 62. The circumferential projection 86 preferably has an axial extent which corresponds to the axial extent of the circumferential fl end 68. By arranging the circumferential projection 86 substantially centrally in the cylinder housing 14, it will be shown in FIG. 3 is obtained by both the circumferential projection 86 on the cylinder the housing 14 and the circumferential 68 end 68 of the piston 22 fi are axed between each radial seal 60, 62. In the intermediate position shown in Fig. 3, the operating cylinder 10 has controlled the in the gearbox 4 existing gears 12 to a neutral position. At the movement of the piston 22 from the first position to the intermediate position, the pin 52 has been moved further into the recess 50 of the sensor 50 54. The sensor 50 thereby sends signals to the control unit 48 about the position of the piston 22 in the cylindrical position. 10 15 20 25 30 housing 14, which means that the control unit 48 can determine which gear is involved. set in gearbox 4. For clarification purposes, control unit 48, valves 44, 46 and pressure source 42 with associated connections and wires omitted in Fig. 3.

To move the piston 22 from that of the fi g. 3 shows the intermediate position to a second shown in Fig. 4 end position is supplied pressurized id uid the first space 34 through the first port 38, together early as the second space 36 is evacuated on fl uid through the second port 40. For to avoid a negative pressure in the third space 58 will fl uid flow in through the third port 56. Thus, the first valve 44 is opened and pressurized fl uid from the pressure source 42 is supplied to the first space 34. The second valve 46 ensures that fl uid can be evacuated through the second port 40. The piston 22 will then be displaced thereto second end position, shown in fi g. 4. The first radial seal 60 will abut sealing against the circumferential projection 86 in the cylinder housing 14 and preventing pressurization id uid to reach the third space 58 formed between the radial seals 60, 62, so that it pressurized fl uide is retained in the first space 34, and cannot reach the third space 58 so as not to be able to leave the cylinder housing 14 through the third port 56. I In the intermediate position shown in Fig. 4, the actuating cylinder 10 has controlled those present in the gearbox 4. gear gears 12 to a second gear position. When the piston 22 moves from the intermediate position to the second end position, the pin 52 has been inserted further into the recess 54 of the sensor 50. The sensor thereby sends signals to the control unit 48 about the position of the piston 22 in the cylinder housing 14. I For clarification purposes, control unit 48, valves 44, 46 and pressure source 42 with associated connections and wires omitted in fi g. 4.

To return the piston 22 to the first end position, the second space 36 is supplied to the second space. whereupon the first and third spaces 34, 58 are evacuated on fl uid. Preferably there is one passage 90 past the sliding bearing 72, so that fl uid can flow to and from the axial of the piston 22 bore 70 via a transverse channel 91 arranged in the second end wall 18, which transverse channel 91 is connected to the second space 36. Thus, the second channel the tube 36 connects to the axial bore 70 of the piston 22 via the passage 90. The the transverse channel 91 extends substantially radially, while the passage 90 extends extends essentially axially.

Fig. 5 shows a sectional view of the operating cylinder 10 according to a second embodiment of present invention in a first state of mind. What distinguishes the first embodiment from the second embodiment is that the sliding bearing 72 is arranged on the lug 74. none of the plain bearings 72 on the lug 74 means that it can be easily disassembled and replaced out by separating the second end wall 18 from the cylinder housing 14 and reassembling it that a new plain bearing 72 is mounted on the lug 74.

The stated components and features stated above may be within the scope of the invention combined between different specified embodiments.

Claims (11)

10 15 20 25 30 10 Patent claims An operating cylinder for a gearbox (4), comprising a cylinder housing (14), which is provided with a first and second end (16, 18) to form a space (20), a piston (22), which is provided with a piston rod (24), which piston (22) divides said space (20) into a first and a second space (34, 36); an opening (28) in the first end (16) through which the piston rod (24) is arranged to extend; a first port (38) in communication with the first space (34); and a second port (40) in communication with the second space (36), through which ports (38, 40) a fl uid are supplied and removed to move the piston (22) relative to the cylinder housing (14), in that the piston (22) is provided with an axial bore (70), which by means of a sliding bearing (72) is arranged to abut against a lug (74) arranged on the second end (18). Cylinder according to Claim 1, characterized in that the bore (70) has a substantially circular shape with a center axis (76) which substantially coincides with the center axis (78) of the piston (22). Cylinder according to Claim 2, characterized in that the lug (74) has a substantially circular shape with a diameter which is smaller than the diameter of the bore (70). Cylinder according to one of the preceding claims, characterized in that the bore (70) and the lug (74) have an axial extension which is equal to or exceeds the stroke of the piston (22). Cylinder according to one of the preceding claims, characterized in that the plain bearing (72) is substantially circular. Cylinder according to one of the preceding claims, characterized in that a third port (56) is arranged in the cylinder housing (14) for removing bort uid from the first and second spaces (34, 36). 10 15 20 11 Cylinder according to one of the preceding claims, characterized in that a first and a second radial seal (60, 62) are arranged between the piston (22) and the cylinder housing (14), which radial seals (60, 62) are designed to slide on the piston (22 ) and the cylinder housing (14) when the piston (22) moves relative to the cylinder housing (14). Cylinder according to one of the preceding claims, characterized in that the plain bearing (72) is arranged in the bore (70) of the piston (22). Cylinder according to one of Claims 1 to 7, characterized in that the plain bearing (72) is arranged on the lug (74). Gearbox (4), characterized in that it comprises an operating cylinder (10) according to any one of claims 1-9. ll. Vehicle (1), characterized in that it comprises a gearbox (4) according to claim 10.