RU2204749C1 - High-torque variable-speed drive - Google Patents

Abstract

FIELD: mechanical engineering; smooth change of gear ratio of machine transmission at transfer of considerable power including stop of driven shaft under load and reverse. SUBSTANCE: proposed drive has housing, input and output shafts, gear ratio selector knob and three-shaft differential gear. Carrier shaft is made integral with output shaft. Fitted on two other shafts are wheels of differential gear with drive mechanisms at relative phase shift of 90 deg. Each drive mechanism includes cam mounted on input shaft , two overrunning clutches, slide block mounted in guides on housing and carriage with cylindrical journal fitted in slot of slide block. Carriage guides are perpendicular to axis of input shaft for turning relative to housing. EFFECT: simplified construction; low cost. 10 dwg

Description

 The present invention relates to mechanical engineering and is intended to smoothly change the gear ratio of the transmission of machines with a large transmitted power, including the stop of the driven shaft under load and reverse.

 High-torque variators are known in which the moment is transmitted from the input to the output shaft by means of cams, carriages, rocker arms, overrunning clutches and a three-shaft differential, and a smooth change in the gear ratio is achieved by changing the lever arms [1] or the relative movement of the rocker arm and cam [1,2]. In well-known variators, a rather complicated, expensive and bulky design takes place.

We take for the prototype the closest high-speed variator in terms of technical essence and the achieved result [3], containing the input shaft with cams and output shafts mounted on bearings in the housing, a gearshift change handle, a three-shaft differential, the carrier shaft of which with the satellite makes up a single link with the output shaft, and on the other two shafts there are mounted differential wheels coupled to the satellite, equipped with the possibility of communicating rotational motion with a relative phase shift of 90 ^o drive fur basics, each of which includes a cam mounted on the input shaft, two overrunning clutches with driven half-couplings kinematically rigidly connected to the differential wheel, mounted on the housing perpendicular to the axis of the input shaft of the guides and the carriage interacting with the cam, a two-arm lever connected to the cam by the end connected to the other end by means of a rack and pinion mechanism, with the possibility of transmitting oscillatory motion, with leading half-clutch overrunning clutches, with the average support two-shouldered ry aha made movable relative to the housing handle gear ratio change.

Signs of a known mechanism (prototype), coinciding with the claimed invention, are as follows. The well-known high-torque variator contains input and output shafts mounted on bearings in the housing, a gear shift knob, a three-shaft differential, the carrier shaft of which with the satellite makes up a single link with the output shaft, and differential wheels coupled to the satellite are fitted with the possibility of communication on two other shafts rotational motion with a relative phase shift of 90 ^o drive mechanisms, each of which includes a cam mounted on the input shaft, two overtaking f couplings with driven half couplings kinematically rigidly connected to the differential wheel, mounted in the guides interacting with the cam perpendicular to the axis of the input shaft of the guides, with the possibility of transmitting oscillatory motion to the leading half couplings of the overrunning couplings with a swinging range varied from the handle of the gear ratio.

 In the known variator, the kinematic connection of the leading coupling halves with the carriage is structurally complex, expensive and cumbersome, which is associated with the chosen method of changing the amplitude of the oscillations of the driving coupling halves of the overrunning couplings.

 The purpose of the invention is to simplify and reduce the cost of construction.

The proposed high-torque variator has the following essential features. It contains input and output shafts mounted on bearings in the housing, a gear shift knob, a three-shaft gear differential, the carrier shaft of which with the satellite makes up a single link with the output shaft, and differential wheels coupled to the satellite are fitted on two other shafts, equipped with the possibility of communicating rotational motion with relative phase shift of 90 ^o actuators, each of which includes a cam mounted on the input shaft, with two freewheel clutches kinematically the driven half-couplings firmly connected to the differential wheel mounted on rails perpendicular to the input shaft of the guides on the housing and kinematically rigidly connected to the leading half-couplings of the freewheel clutch slider with a groove perpendicular to its guide groove, a carriage mounted on the guides with a cylindrical pivot mounted on the slide groove axis of the input shaft with the possibility of rotation relative to the housing from the handle changes the gear ratio.

 Distinctive features of the prototype features of the invention are the following. In the proposed high-torque variator, the drive mechanism is equipped with guides mounted perpendicular to the input shaft on the housing and kinematically rigidly connected to the leading half-couplings of the overrunning clutches with a slider with its perpendicular guide groove, and a cylindrical axle installed in the slider groove is made on the carriage; relative to the housing from the handle changes the gear ratio.

 In Fig.1 and 2 presents a design variant of high-torque variator: Fig.1 - cross section; figure 2 is a longitudinal section; figure 3, 4 and 5 - the position of the links of the variator with different combinations of the handle changes the gear ratio; in FIG. 6 - cam; figure 7 - graphs of the angular velocities of the links of the differential gear; on Fig, 9 and 10 are fragments of design options.

High torque variator (Fig.1-5) contains installed in the bearings of the housing 1 input 2 and output 3 shafts; gear shift knob 4; a three-shaft differential, in which the carrier shaft 5 carrying the satellite 6 forms a single link with the output shaft, the other two shafts 7a and 7b with the differential wheels 8a and 8b are freely mounted on the output shaft; as well as two differential wheel drive mechanisms. Each drive mechanism includes two overrunning clutches 9 ₁ and 9 ₂ mounted on the shaft 7, the leading coupling halves of which 10 ₁ and 10 ₂ , are equipped with gear sectors 11 ₁ and 11 ₂ with an involute tooth profile; cam 12 mounted on the input shaft (two cams 12a and 12b rotated 90 ^° relative to each other); a slider 14 installed in the guides 13 on the housing, with a groove 15 perpendicular to its guide 13 and two toothed racks 16 interacting with the gear sectors 11; a carriage 17 installed in the guides 18 and in contact with the cam 12 with cylindrical protrusions 19, and with a groove 15 of the slider - an axle 20. The guides of the carriages 18 are mounted on a bearing 21 coaxial to the input shaft and are equipped with a worm gear 22 engaged with the worm 23, on which fixed gear change knob 4 with pin 24.

High torque variator works as follows (Fig.1 - 5). When the input shaft rotates at a speed of ω _{2, the} cam 12 reports the reciprocating movement of the carriage 17 along the z axis, the angle of inclination β of which can be changed with the handle of the gear ratio 4, Н is the distance between the extreme positions of the carriage. The carriage with its pin 20 transmits a reciprocating movement to the slider 14 along a straight line OA connecting the centers of the input and output shafts, h _max = Hcosβ is the distance between the extreme positions of the slider (figure 4). The slider by means of a gear transmission reports oscillatory movements to the leading coupling halves 10 of two overrunning clutches 9. In Figs. 3 and 4, the direction of transmission of rotation to the differential wheel is shown by a solid arrow, dashed - idle, i.e. when moving to the right, the slider rotates the differential wheel with a freewheel 9 ₁ , when moving to the left - a freewheel 9 ₂ . The gear train with involute gearing provides a proportional relationship of the movement of the slide h _p with the rotation angle γ of the coupling half 10, i.e.

γ = h _p / r, (1)
therefore, the swing range of the coupling half
λ (β) = h _max / r = Hcosβ / r, (2)
where r is the radius of the centroid of the gear sector.

In FIG. 3-5, three carriage positions are given. For β = 0, we have h _max = H, and the amplitude of the oscillations is maximum: λ (0) = λ _max = H / r; at β = 90 ^° we have h _max = 0, therefore, λ (90 ^° ) = 0, there is no transmission of rotation to the output shaft.

6 shows theoretical P _t and the working _Example cam profiles, α - angle of rotation of the x-axis of symmetry of the cam. The distance to the point of the theoretical profile from the O axis is R = R ₀ + h (α), where h (α) is the carriage stroke. The slider stroke is related to the angles α and β by the ratio
h _p (α, β) = h (α) cosβ. (3)
Theoretical profile П _т - the geometrical place of points in the plane of the cam of centers В of cylindrical protrusions 19 with radii r _p . The working profile P _p is the envelope of circles with radii r _p in the plane of the cam.

From the properties of the differential it follows that the angular velocity of the output shaft
ω ₃ = 0.5 (ω _8a + ω _8b ),
where ω ₈ = ω ₂ | dγ / dα | - the angular velocity of the differential wheels.

например, для |dU(α)/dα| = (2/π)sin²α это условие выполняется, а характер угловых скоростей звеньев дифференциала для этого случая показан на фиг.7.We write the angle of rotation of the leading coupling half in the form
γ _a = λU (α), γ _b = λU (α + π / 2) = γ _a (α + π / 2),
where U (α) is the cam profile function (0≤U (α) ≤1).
To ensure uniform rotation of the input shaft with ω ₂ = const, the following conditions must be met:

for example, for | dU (α) / dα | = (2 / π) sin ² α this condition is satisfied, and the nature of the angular velocities of the differential links for this case is shown in Fig. 7.

т. е. зависит только от положения рукоятки изменения передаточного отношения, что доказывает эффективность предлагаемого высокомоментного вариатора.We rewrite the expressions for γ _a using (1), (2) and (3) in the form
[h (α) cosβ] / r = [Hcosβ / r] U (α),
whence the carriage displacement is equal to h (α) = HU (α).
For one revolution of the input shaft (φ ₂ = 2π), the angle of rotation of the output shaft is
φ ₃ = 0.5 (φ _a + φ _b ) = 0.5 (4λ) = 2Hcosβ / r,
therefore, the gear ratio of the variator will be

i.e., it depends only on the position of the handle of the gear ratio change, which proves the effectiveness of the proposed high-torque variator.

 The type of rigid kinematic connection of the slider with the leading half-coupling of the freewheel is not critical.

For example, uniform rotation of the output shaft can be achieved by using hinged chains 25 ₁ and 25 ₂ pivotally connected to the slider and the driving coupling half (Fig. 8), while the support surface 26 is made on the slider, and the links of the hinged chain 27 are made with a broken contact profile 28 (Fig. 9), providing the necessary rigidity when transmitting movement of the compressed links. With a small step S of the links, relation (1) is satisfied with sufficient accuracy for practice.

In figure 10, the slider is connected to the coupling halves by means of earrings 29, transmitting movement from the slide to the leading coupling halves by means of the fingers 30 ₁ and 30 ₂ fixed to them. In this case, the variator is also operational, but will have some uneven rotation of the output shaft, due to the failure of relation (1).

 The rigid kinematic connection of the driven coupling halves with the differential wheels can be direct, i.e. by fixing two coupling halves on the differential wheel, and using intermediate kinematic links: gears, rocker arms, etc.

 CVT reverse is provided by reversing overrunning clutches.

Sources of information
1. DE 3309044 A1, F 16 H 29/08, 03/14/83 (B. Rindfleisch).

 2. RU 2169870 C2, F 16 H 29/08, 05/14/99 (B.V. Pylaev).

 3. RU 2147701 C1, F 16 H 29/08, 02/25/98 (B.V. Pylaev).

Claims (1)

High-torque variator, comprising input and output shafts mounted on bearings in the housing, a gear shift knob, a three-shaft differential, the carrier shaft of which with the satellite makes up a single link with the output shaft, and differential wheels coupled to the satellite are fitted with the possibility of communication on two other shafts rotational motion with a relative phase shift of 90 ^o drive mechanisms, each of which includes a cam mounted on the input shaft, two overrunning clutches with driven half-couplings kinematically rigidly connected to the differential wheel, mounted in the guides perpendicular to the axis of the input shaft of the guides, a carriage interacting with the cam with the possibility of transmitting oscillatory motion to the leading half-couplings of overrunning clutches with an oscillation range that varies from the handle of the gear ratio, characterized in that each drive mechanism is equipped with an installed in the guides perpendicular to the input shaft on the housing and kinematically rigidly connected to the leading half-couplings These couplings have a slide with a guide groove perpendicular to it, and a cylindrical pin mounted in the slide of the slide is mounted on the carriage, while the guide carriages are mounted with the possibility of rotation relative to the housing from the handle to change the gear ratio.

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