RU50922U1 - GEARBOX AND GEARSHIFT GEARBOX GEARBOXES - Google Patents

Abstract

Appointment: various branches of mechanical engineering, in particular transport mechanical engineering, for example, tractor engineering, is intended for use as a separate gearbox as a whole or as a modular unit for creating gearboxes of a modular design with an extended transmission range. EFFECT: increased transmission efficiency, reduced axial dimension of the box, reduced manufacturing and repair costs, reduced switching efforts. The essence of the group of utility models: it is proposed a gearbox on the input and output shafts of which at least four pairs of gears of constant engagement are placed, installed in alternating order so that the gear rigidly connected to the shaft alternates with the gear freely mounted on it, and each gear pair is formed freely installed a gear with a rigidly connected gear and between two adjacent freely mounted gears there is a switching mechanism made common to them in the form of a three-position hydraulic cylinder a, the cavity of which is formed by recesses in the hubs of these gears, and the piston is made ring-shaped covering the shaft having a constant connection with it, for example, a spline connection. The piston is a working body of the mechanism and its contact elements, for example, splines, alternately interacts with the response elements of a particular gear, connecting it to the shaft. When the gear is rigidly connected to the shaft between these gears, it is mounted on the piston with the help of a splined joint so that the piston does not completely disengage from it. The cylinder cavity is connected to an external electro-hydraulic control system through channels made in the shaft and a hydraulic switch installed on it. Switching can be carried out on the input and output shafts - this extends the range of gears. The mechanism is compact, does not require additional space to accommodate its components; hydraulics reduce switching forces.

Description

A group of utility models relates to mechanical engineering, more precisely to gears with a stepwise change of gear ratio for various engineering industries, it is intended mainly for vehicles, mainly for industrial purposes, in particular tractors, and can be used as a separate gearbox as a whole or as modular unit for creating modular gearboxes with a wide range of gears.

The problem solved by the proposed group of utility models is to create an economical compact gearbox with a high level of unification and simplification and improved ergonomic performance.

Known gearboxes (RF patents No. 1463526, 60 K 17/08, 1989 and No. 2216455, 60 K 17/08, 2003), containing input and output shafts, several pairs of gears of constant gearing, one of which rigidly connected with the shaft, while others are freely mounted on it, and a gear switching mechanism with a controlled working body, made with contact elements interacting with the mating elements of the shaft and gears. The disadvantages of these analogues include the presence of additional intermediate shafts with gears and other elements, which leads to an increased number of parts and connections in the gearbox and does not allow to reduce its overall axial size, and also worsens its output parameters due to power losses in additional gears, and due to transmission range limitations, as switching mechanisms are provided only on separate shafts, for example: on the input shaft, as in the design of the RF patent No. 1463526; at the intermediate and output as in the design according to the patent of the Russian Federation No. 2216455.

Known gearbox, the design of which is compact (RF patent No. 1698536, F 16 H 3/08, 1991), containing two parallel shafts: input and output, located on these shafts several pairs of gears of constant meshing, one of which is rigidly connected to the shaft, and others are freely mounted on it, and a gear switching mechanism made with a controlled movable working body interacting with the shaft and gears.

This gearbox by the number of matching essential features is the closest analogue of the proposed and is defined as a prototype.

The prototype contains five pairs of gears of constant gearing. On the input shaft, one gear is rigidly connected to the shaft, the rest on this shaft are installed freely, on the output shaft of the gear are installed freely. The output shaft is hollow, a pull-out key is located inside it, which is a movable working body of the switching mechanism - it engages with the reciprocal grooves of one or another gear, connecting it to the shaft.

The disadvantages of the prototype:

- reduced efficiency due to the large number of gears, i.e. the length of the kinematic chain along which power is transmitted;

- reduced power due to the presence of serious stress concentrators on the driven shaft (it is hollow, and it has a slot for the exhaust key);

- increased axial clearance due to the execution of gears in blocks with a small number of gears.

The technical result obtained from the implementation of the proposed gearbox is to increase the reliability and efficiency of the transmission, reducing the axial dimension of the box while expanding the gear range, reducing the cost of manufacturing and repairing the product.

The technical result is achieved in that in a gearbox containing two parallel shafts: input and output, several pairs of gears of constant gear located on these shafts, some of which are rigidly connected to the shaft and others are freely mounted on it, and the gear shifting mechanism, made with a controlled movable working body with contact elements interacting with the mating elements of the shaft and gears, unlike the prototype, at least four shocks are installed on the input and output shafts gears and one of the aforementioned switching mechanism, the gears on each shaft are arranged in alternating order so that the freely mounted gear alternates with the gear rigidly connected to the shaft, and the engagement pair is formed by a rigidly connected gear with a freely installed gear; the switching mechanism is located on the shaft between two adjacent freely mounted gears and is made common to them, and the gear placed between them in alternating order is made with the possibility of constructive alignment with the switching mechanism, for example, mounted on its working body.

In particular types of box construction, the first gear on the input shaft is rigidly connected to the shaft, or is freely mounted on it.

Placing the gears on the shaft in alternating order and composing a pair of permanent gearing from two gears with different types of interconnection with the shaft (freely installed with rigidly connected) ensures a significant reduction in the axial dimension of the box when a sufficiently wide range of gear ratios is achieved, and at the same time

power transmission chains are getting shorter, therefore power losses are reduced and transmission efficiency is increased.

The presence of a switching mechanism for each pair of freely mounted gears, i.e. on each shaft, extends the gear range, allows the transmission of torque along shortened kinematic chains.

Thanks to the use of similar parts and assemblies in the construction of the box, a high level of simplification and unification is achieved, which makes the manufacture and repair of the product as a whole and its individual components cheaper.

The placement of one of the gears together with the working body of the gear mechanism also ensures a compact gearbox.

Known mechanisms for switching gears in gearboxes containing a working body movable along the shaft, interacting selectively with gears, in which, to ensure the compactness of the gearbox, the working body is located inside the hollow shaft and is made in the form, for example, of an exhaust key (RF patent No. 1698536, F 16 3/08, 1991) or a displacement sleeve with jammed bodies - balls (RF patent No. 1749065, 60 K 17/08, 1992).

The disadvantage of these analogues is the decrease in reliability due to the fact that the shafts are hollow and they have serious stress concentrators.

The closest analogue of the proposed mechanism is the gear shift mechanism according to the USSR patent No. 692748, 60 K 17/08, 1979, made common to two adjacent gears freely mounted on the shaft, containing a working body movable along the shaft from the drive, provided with external contact elements (splines) for interacting with mating gear elements located on the surface of recesses made in gear hubs, and internal (also splines) for interacting with mating shaft elements.

By the number of matching essential features, this analogue is defined as a prototype of the proposed switching mechanism.

In the prototype, the working body of the mechanism is made up of several parts of a relatively complex configuration and is driven through mechanical multi-link kinematics, which leads to high costs for the manufacture and repair of the product, increased dimensions of the gearbox as a whole, and is also inconvenient in operation, because requires increased muscular effort of the operator. The presence of a large number of parts with connections in the design of the mechanism negatively affects the efficiency and reliability of the gears in general.

The technical result obtained from the use of the proposed gearshift mechanism is to implement the task posed to the group of utility models: ensuring compactness, increasing efficiency and reliability of the gearbox, as well as improving its ergonomic performance by facilitating working conditions (gear shifting without great physical effort of the operator )

To achieve a technical result, a gearbox gear shifting mechanism comprising a working body movable from a drive along the shaft, provided with contact elements, for example, splines, external for interacting with mating gear elements in recesses made in their hubs and internal for interacting with mating shaft elements, unlike the prototype, it is made in the form of a hydraulic cylinder with an annular piston covering the shaft as a working body and an electro-hydraulic control system as a drive. The cylinder cavity is formed by the aforementioned internal recesses in the hubs of the gears, which are sealed, and is connected to the electrohydraulic control system with the possibility of providing controlled positioning of the piston in three positions: two extreme - working and intermediate - neutral, while the piston is made with the possibility of fixing it relative to the shaft.

Additional differences are that:

- the cylinder cavity is connected to the electro-hydraulic control system for channels made in the shaft body through a hydraulic switch mounted on the shaft;

- the mechanism is equipped with a spring-loaded ball retainer interacting selectively with the internal radial grooves on the piston.

Figure 1 shows the layout of the gearbox;

figure 2 is a General view of the gearbox in the context:

figure 3 is a General view of the switching mechanism in the form of a hydraulic cylinder with a piston;

figure 4 - section aa along the shaft of figure 3;

5 is a section bB along the shaft of figure 3;

6 is a section bb in the shaft of figure 3;

Fig.7 is a sectional view of a piston of a hydraulic cylinder;

Fig.8 is a section GG in Fig.7 (view of the radial grooves);

Fig.9 is a General view of the gears;

figure 10-13 - illustration of the operation of the gearbox;

In the gearbox housing 1, the input shaft 2 and the output shaft 3 are located, and several pairs, at least four, gears of constant gear located on these shafts are located, some of which are rigidly connected to the shaft, and others are freely mounted for rotation relative to the shaft.

On each shaft, the gears are arranged in the following alternating order: the freely installed (SU) gear alternates with the gear rigidly connected to the shaft (ZhS). So in a specific example of the design of the gearbox (Fig. 1; 2), two ZhS gears 4 and 5 and two SU gears 6 and 7 are installed on the shaft 2, i.e. starting from the ZhS gear, and on the shaft 3: two gears SU 8 and 9 and two gears ZhS 10 and 11, i.e. starting from SU gear. The type of the first gear on the input shaft (SU or ZhS) varies based on the specific constructive design of the gearbox and it determines the general order of alternating gears on both shafts of this gearbox, in which each gearing pair is formed by the SU gear of one shaft and the ZhS gear of the other shaft.

On the input shaft 2 between two adjacent control gears 6 and 7 and on the output shaft 3 also between two adjacent control gears 8 and 9 are placed switching mechanisms 12 and 13, respectively. Each of them, to ensure the compactness of the gearbox, is common to the corresponding two gears and can have any known structural form, for example, in the form of a gear or disk friction hydraulic clamping clutch.

The gears are connected to the shaft when interacting with it moving along the shaft of the working body of the mechanism.

The most effective in solving the problem of ensuring the compactness of the box is the proposed design of the switching mechanism (Fig. 3), made in the form of a three-position hydraulic cylinder with a ring-shaped piston 14 covering the shaft as a movable working body and an external electro-hydraulic control system, as a drive that includes discharge lines, drain line, three-position spools, pump (not shown in the drawing).

The cavity 15 of the hydraulic cylinder is formed by internal recesses 17 in the hubs of the gears and the end sealing rings 18 and 19 (figure 3). The piston 14 covers the shaft and interacts with it by contact elements 20, for example splines, on the inner diameter. The outer diameter of the piston 14 has contact elements 21, for example splines, for interaction with mating contact elements 23 made in the recesses 17.

The cavity 15 of the hydraulic cylinder is connected to an external electro-hydraulic control system through channels 24, 25 and 26, made in the shaft, two of which 24 and 26 exit, respectively, to the left and right (according to the drawing) parts of the cavity 15, channel 25 goes to the internal splined surface of the piston 14 so that it overlaps in the middle position of the piston 14 and opens when the piston 14 is in one of the extreme positions. To supply the control pressure to the cavity 15, which provides controlled positioning of the piston 14 in three positions: two extreme (working) and intermediate (neutral), a hydraulic switch 27 is mounted on the shaft, the channels of which 28, 29 and 30 are connected to the electrohydraulic control system, and with which channels 24, 25, 26 connected cavity 15.

To fix the preset position of the piston 14 when relieving pressure in the switching mechanism, there is a spring-loaded ball retainer 31, selectively interacting with one of the three grooves 32 made on the inner diameter of the piston.

The switching mechanisms 12 and 13 are made identically and connected to the common mentioned electrohydrosystem control.

When placing another ZhS 5 gear between two adjacent SU gears 6 and 7 (Fig. 3), gear 5 is installed using a spline connection on the piston 14 and the inner surface of its hub is the part forming the cavity 15. The piston 14 the neutral position is completely in contact with the gear 5, and when moving to one of the extreme positions, is in contact with it its surface. Thus, through the chain gear-piston-shaft, this gear is constantly rigidly connected to the shaft. To protect against axial displacements of this gear, thrust rings 33 and 34 are made of antifriction material. At the same time, these rings seal the cavity 15.

Gear shifting is carried out as follows.

The movement of the piston 14 is due to the differential pressure of the oil supplied through the channels 24, 25, 26. At the initial moment, the oil is supplied simultaneously through all three channels, while the piston 14 remains in the position that it had previously occupied before the moment of gear shifting. The movement of the piston 14 will occur after the oil pressure is removed in one of the channels due to the connection to the drain line of the electrohydro control system. At the same time, lowering the oil pressure in the cavity 15 to the left or to the right of the piston 14 will cause it to move all the way to the low pressure side. To move the piston 14 to the neutral position, the pressure in the channel 25 is removed, while the piston will begin to move until it blocks the channel 25, then the pressures to the right and left of the piston 14 will equalize and the piston will take a neutral position.

After the gearshift process is completed, the pressure in the channels must be relieved, and the desired piston position is supported by the clamp 31.

A description of the operation of the gearbox with the proposed switching mechanism is given on a specific example of its implementation with four pairs of gears of constant gearing (Fig.10-13).

In the initial position (figure 2), none of the freely installed gears 6, 7, 8, 9 are not connected to its shaft, i.e. the pistons 14 and 14 'of the switching mechanisms 12 and 13 are in the middle neutral position, respectively, the torque from the shaft 2 to the shaft 3 is not transmitted. To engage the transmission, one of the freely installed gears 6, 7, 8 or 9 must be connected to its shaft. Since each gearing pair is formed by one freely mounted gear and one gear having a rigid connection with its shaft, then after the connection

freely mounted gears with a shaft, torque will be transmitted from shaft 2 to shaft 3.

The connection of freely mounted gears 6 or 7 with the shaft 2 is carried out by displacing the piston 14, respectively, to the left or right position.

In order to shift the piston 14 to the left position, the channel 26 is connected to the discharge line of the electro-hydraulic control system, and the channel 24 is connected to the drain, the channel 25 is closed. To move the piston 14 to the right position, channel 24 is connected to the discharge line of the electrohydrosystem, and channel 26 is connected to the drain, channel 25 is closed. In order to move the piston 14 to the middle position from any extreme, it is necessary to connect the channel 25 to the drain, and the channels 24 and 26 to the discharge line of the electrohydrosystem, then the piston 14 will be shifted to the middle position until it blocks channel 25 and the pressure in the extreme parts of the cavity 15 is not equal. After the transmission is engaged, the pressure in the channels is removed, and the piston 14 is held in position by means of a ball lock 31.

Similarly, the operation of the switching mechanism 13 of the freely mounted gears 8 and 9 of the shaft 3 occurs with a controlled three-position movement of the piston 14 '.

First stage.

The torque is transmitted from the shaft 2 to the gear 4 rigidly sitting on it, from the gear 4 to the gear 8 freely mounted on the shaft 3, from the splines on the gear hub 8 to the outer splines of the piston 14 ', from the piston 14' to the shaft 3.

Second stage.

The torque is transmitted from the shaft 2 to the gear 5 through the piston 14, from the gear 5 to the gear 9 freely mounted on the shaft 3, from the splines on the hub of the gear 9 to the outer splines of the piston 14 ', from the piston 14' to the shaft 3.

Third stage.

The torque is transmitted from the shaft 2 to the piston 14, from the external splines of the piston 14 to the splines of the hub of the gear 6 freely mounted on the shaft 2, from the gear 6 to the gear 10, from the gear 10 to the piston 14 ', from the piston 14' to the shaft 3.

Fourth step.

The torque is transmitted from the shaft 2 to the piston 14, from the external splines of the piston 14 to the splines of the hub of the gear 7 freely mounted on the shaft 2, from the gear 7 to the gear 11 rigidly mounted on the shaft 3, from the gear 11 to the shaft 3.

The implementation of the switching mechanism due to the surfaces of the gears makes it as compact as possible, its placement does not require additional space and, therefore, helps to reduce the axial dimension of the box.

The use of hydraulic pressure as a control drive reduces the switching effort, facilitates the working conditions of the vehicle operator, helps to automate the shift, improves the ergonomic performance of the gearbox.

Such a hydraulically controlled switching mechanism is the simplest in design and has smaller dimensions compared to mechanically controlled (lever) drives.

Claims (6)

1. A gearbox containing two parallel shafts: input and output, located on these shafts are several pairs of gears of constant gearing, some of which are rigidly connected to the shaft, while others are freely mounted on it, and a gear shifting mechanism made with a controlled movable working body with elements interacting with the mating elements of the shaft and gears, characterized in that at least four gears and one said switching mechanism are installed in it on the input and output shaft, the gears on the shaft are arranged in alternating order so that the freely mounted gear alternates with the gear rigidly connected to the shaft, and the pair of gears is formed by a rigidly connected gear with a freely installed gear, the switching mechanism is located on the shaft between two adjacent freely installed gears and is common to them, and the gear located between them in alternating order is made with the possibility of constructive alignment with the switching mechanism, for example, mounted on its working body. 2. The gearbox according to claim 1, characterized in that the first gear on the input shaft is made rigidly connected with the shaft. 3. The gearbox according to claim 1, characterized in that the first gear on the input shaft is made freely mounted on the shaft. 4. The mechanism for switching gears of the gearbox, comprising a working body movable from the drive along the shaft, provided with contact elements, for example, splines: external for interacting with mating gear elements in recesses made in gear hubs and internal for interacting with mating shaft elements, characterized in that it is made in the form of a hydraulic cylinder with an annular piston covering the shaft as a working body and a control electro-hydraulic system as a drive, the cylinder cavity is formed at omyanutymi internal recesses in the hubs of the gears, a seal and is connected to the control elektrogidrosisteme managed to provide a positioning of the piston in three positions: two extreme - the working and intermediate - neutral, wherein the piston is configured to lock it relative to the shaft. 5. The switching mechanism according to claim 4, characterized in that the cylinder cavity is connected to the control electro-hydraulic system by channels made in the shaft body through a hydraulic switch mounted on the shaft. 6. The switching mechanism according to claim 4, characterized in that it has a spring-loaded ball retainer that selectively interacts with grooves on the piston.