CN115076313A - One-way cam pressurized continuously variable transmission - Google Patents

One-way cam pressurized continuously variable transmission Download PDF

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Publication number
CN115076313A
CN115076313A CN202210791972.1A CN202210791972A CN115076313A CN 115076313 A CN115076313 A CN 115076313A CN 202210791972 A CN202210791972 A CN 202210791972A CN 115076313 A CN115076313 A CN 115076313A
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cam
driven
driving
pressurizing
disc
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顾万玉
肖艳
程越
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Changzhou Dongfeng Cvt Co ltd
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Changzhou Dongfeng Cvt Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F16H9/16—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts
    • F16H9/18—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts only one flange of each pulley being adjustable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H53/00—Cams ; Non-rotary cams; or cam-followers, e.g. rollers for gearing mechanisms
    • F16H53/08—Multi-track cams, e.g. for cycles consisting of several revolutions; Cam-followers specially adapted for such cams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/32—Friction members
    • F16H55/52—Pulleys or friction discs of adjustable construction
    • F16H55/56—Pulleys or friction discs of adjustable construction of which the bearing parts are relatively axially adjustable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F16H61/66254—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members controlling of shifting being influenced by a signal derived from the engine and the main coupling
    • F16H61/66268—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members controlling of shifting being influenced by a signal derived from the engine and the main coupling using purely mechanical sensing or control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F16H61/66272—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members characterised by means for controlling the torque transmitting capability of the gearing

Abstract

The invention relates to a one-way cam pressurized stepless speed changer, which is characterized in that a pressurizing track line is a monotonously-changing two-dimensional line segment, so that a cam pressurizing mechanism is a one-way pressurizing cam, and a limited disc spring is used as an elastic pressurizing element to meet the requirement of back dragging pressurization caused in the one-way transmission process, so that the pressurizing cam of the whole stepless speed changer has a wider compensation range and a more compact structure, and is more suitable for being applied to the working conditions with larger speed ratio range and/or the requirement of no positive and negative rotation.

Description

One-way cam pressurized continuously variable transmission
Technical Field
The invention belongs to the field of power mechanical transmissions, and particularly relates to a stepless transmission pressurized by a one-way cam.
Background
The cone disc type continuously variable transmission is more and more widely used in machinery, and in the prior art, a pressurizing mechanism is mostly arranged on the side of a movable cone disc, for example, a method of pressurizing the movable cone disc of the continuously variable transmission in real time by matching an end face cam with a hydraulic system or a space cam mechanism directly pressurizing the movable cone disc is adopted. The stroke of the common end face cam in the arrangement mode cannot meet the axial stroke required by the speed regulation of the movable cone disc. Or the axial stroke required by the speed regulation of the movable conical disc is met by matching with a hydraulic system or adding an axial gear of a cam mechanism. The structure is more complex and not compact enough.
At present, the conical disc type stepless speed changer is mainly used in a bidirectional power machine, so that the use effect is better, but in the actual use process, a plurality of unidirectional power machines are provided, and the rotating direction and the load direction of the unidirectional power machines are kept unchanged in one direction, such as a hydraulic machine, a wind power generation machine, a propeller plane and the like; or the difference of the loading magnitudes in the positive and negative loading directions is large, for example, the difference between the driving torque of the transportation machinery and the anti-drag torque of the engine is large.
Chinese patent CN103867678B discloses a conical disc type continuously variable transmission, specifically discloses a pressure mechanism with an end cam, and a pressure structure with a V-groove structure, the pressure structure thus arranged realizes bidirectional pressure in forward and reverse directions, so that the service life of the system is prolonged, and the reliability is improved. However, in the case of large difference between the forward and reverse loads or one-way transmission, the reverse cam groove causes the stroke of the pressurizing roller to be long, thereby affecting the dynamic performance of the system and the service life of the whole system.
Disclosure of Invention
In view of the above technical problems, the present invention aims to provide a one-way cam pressurized continuously variable transmission with low cost, high reliability and good transmission efficiency.
The method is realized by the following technical means:
a stepless speed changer with one-way cam pressurization comprises a driving shaft, a driving fixed cone disc, a driving movable cone disc, a driven shaft, a driven fixed cone disc, a driven movable cone disc and a steel flexible transmission element, wherein the driving fixed cone disc and the driving movable cone disc form a driving cone disc set, the driven fixed cone disc and the driven movable cone disc form a driven cone disc set, and the driving cone disc set and the driven cone disc set work in an environment with lubricating oil through the clamped steel flexible transmission element.
The stepless transmission also comprises a one-way cam pressurizing mechanism, and the one-way cam pressurizing mechanism is arranged on the back of the driving fixed cone disc and/or the driven fixed cone disc; the one-way cam pressurizing mechanism comprises a driving cam, a driven cam, a rolling body and an elastic pressurizing element, wherein the driving cam is connected with a driving shaft and/or a driven shaft in a non-rotation-allowed mode (such as direct fixed connection, key, welding, press fitting, interference fit or bonding); the driven cam is connected with the driving fixed cone disc and/or the back of the driven fixed cone disc in a mode (such as direct fixed connection, key connection, welding, press fitting, interference fit or adhesion) that mutual rotation is not allowed; the end surfaces of the driving cam and the driven cam are respectively provided with n raceways or pressurizing surfaces which are uniformly distributed in the circumferential direction; the n rolling bodies are arranged in the roller path between the driving cam and the driven cam; wherein n is more than or equal to 3 and less than or equal to 9; the raceway comprises a starting section, a pressurizing section and a terminating section after being unfolded along the circumferential direction, the raceways or the pressurizing surfaces of the driving cam and the driven cam are arranged oppositely, and the driving cam and the driven cam are connected through rolling bodies clamped between the oppositely arranged raceways or the pressurizing surfaces.
The pressurizing section is a one-way pressurizing section, the pressurizing section is a three-dimensional curved surface which is constructed by the movement of a semicircular cross section consisting of two sections of non-concentric circular arcs along a trajectory line on a cylindrical surface which is parallel to the axis of the conical disk and takes the axis of the conical disk as the rotation center, the cylindrical surface where the trajectory line is positioned is unfolded into a plane, namely, an unfolding line of the trajectory line of the pressurizing section is unfolded, and the unfolding line of the trajectory line of the pressurizing section is a two-dimensional line section which changes monotonously.
Preferably, the included angle between the pressurizing section, which is formed by expanding the raceway or the pressurizing surface on the end surface of the driving cam along the circumferential direction, and the vertical plane of the rotation center line of the conical disc is alpha 1 (ii) a The included angle between the pressurizing section and the vertical plane of the rotation center line of the conical disc after the roller path or the pressurizing surface on the end surface of the driven cam is expanded along the circumferential direction is alpha 2 (ii) a Gamma is the included angle between the conical surface generatrix of the driving conical disk group and the driven conical disk group of the continuously variable transmission and the vertical plane of the conical disk rotation center line, or the included angle between the tangent line of the conical surface generatrix of the driving conical disk group and the driven conical disk group of the continuously variable transmission at the geometric midpoint and the vertical plane of the conical disk rotation center line;
i max is a continuously variable transmissionThe designed maximum transmission ratio of (a) is,
Figure BDA0003734198070000031
wherein R is Wmin1 The minimum working radius of the driving cone disk group is the minimum enveloping radius of a contact area of the cone disk and the steel flexible transmission element; r Wmax2 For the maximum working radius of the driven cone disk group, namely the maximum enveloping radius of a contact area of the cone disk and the steel flexible transmission element, the parameters satisfy the following relation:
Figure BDA0003734198070000032
Figure BDA0003734198070000033
preferably, a needle bearing is arranged between the driving cone disc set and/or the driven cone disc set connected with the driven cam and the driving shaft and/or the driven shaft; elastic pressing elements are arranged between the driving shaft and/or the driven shaft and the driving cam and/or between the driven cam and the conical disc.
Preferably, the elastic pressing element is a helical spring or the elastic pressing element is one or more disc springs, one axial end of each disc spring is in contact with the one-way cam pressing mechanism in a direct or indirect mode, the other end of each disc spring is in contact with the driving shaft or the driven shaft in a direct or indirect mode, the main pressing direction of each disc spring is the axial direction, and the maximum total axial thrust of the elastic pressing element is F 1 In units of kilonewtons (kN), R max1 Is the maximum value of the outer radius of the driving cone group and has the unit of mm, R max2 The included angle between the vertical plane of the cone disc rotation center line and the generatrix of the cone disc conical surfaces of the driving cone disc set and the driven cone disc set of the continuously variable transmission or the included angle between the vertical plane of the cone disc rotation center line and the tangent line of the geometric midpoint of the cone disc conical surface generatrix of the driving cone disc set and the driven cone disc set of the continuously variable transmission is the maximum value of the outer radius of the driven cone disc set, and the unit is mm; t is the input maximum torque of the continuously variable transmission inNewton-meter (N.m) satisfies
Figure BDA0003734198070000041
Preferably, the rolling bodies are steel balls, and the diameter d of the steel balls is more than or equal to 0.04 (R) max1 +R max2 ) Wherein R is max1 Is the maximum value of the outer radius of a driving cone disc group of the continuously variable transmission, and the unit is mm and R max2 The maximum value of the outer radius of the driven cone disc set of the continuously variable transmission is expressed in mm.
Preferably, the surface hardness of the cam race is more than or equal to HRC 56; the surface hardness of the rolling element is HRC58 or more.
A power machine uses the aforementioned one-way cam-pressurized continuously variable transmission.
Preferably, the power machine is a flight machine, a power generation machine or an agricultural power machine.
Preferably, the agricultural power machine is a tractor.
The term "monotonic variation" as used herein refers to a tendency of a mathematical curve to monotonically increase or decrease.
The invention has the technical effects that:
1, because the roller path of the cam is only provided with a pressurizing section in one direction and is not provided with a reverse pressurizing section, the cam-pressurized continuously variable transmission with one-way arrangement is provided, compared with the structure (the same pressurizing sections, namely the so-called V-shaped sections, are arranged in both directions) utilizing a V-shaped roller path or a pressurizing surface in the prior art, the axial movement caused by system deflection and system deformation in the speed ratio change process can be better compensated by arranging a unilateral roller path structure, the structure is more compact, and the cam-pressurized continuously variable transmission is more suitable for working condition application with larger speed ratio range and/or larger torque, and is provided with cam compensation amount caused by corresponding system deflection in different speed ratio ranges of a common straight bus continuously variable transmission shown in figure 1. The invention is more suitable for occasions with unidirectional rotation and unidirectional torque requirements, has simpler structure and low processing and assembling cost.
2, in order to ensure the reliability of the friction type stepless speed change transmission and reduce the power loss caused by overlarge pressurizing force, the pressurizing angle is optimized, and the pressurizing angle determined by the formula set by the invention can lower the power loss and improve the system efficiency on one hand, and can ensure the realization of the pressurizing function and improve the system reliability on the other hand.
3, the diameter of the cam roller (namely the rolling body) is specifically limited, so that the cam roller is more suitable for the specific working mode of the pressurization of the one-way cam, the contact strength of the cam roller during the high-load working is improved, and the fatigue life of the system is prolonged.
4, through specifically limiting the axial elastic pressurizing element (preferably a disc spring), and specifically limiting the range value of the maximum thrust of the elastic pressurizing element, compared with the bidirectional cam pressurizing mechanism which needs to provide the axial force required by the forward and reverse power switching, the arrangement mode of the invention is more suitable for the occasions with little requirement on unidirectional rotation or reverse torque, and can effectively avoid the slippage of rigid flexible transmission elements such as chains and the like on the surface of a conical disc under impact load and the chain slippage caused by reverse dragging, thereby greatly improving the overall service life of the system.
Drawings
Fig. 1 shows the cam compensation amount caused by the corresponding system offset in the speed range of 4.5 of the ordinary straight-bus stepless speed change device.
Fig. 2 is a three-dimensional exploded view of a continuously variable transmission according to embodiment 1 of the present invention.
Fig. 3 is a schematic structural view of an active cam according to embodiment 1 of the present invention.
Fig. 4 is a circumferential raceway development of the active cam raceway or pressing surface of embodiments 1 and 2 of the present invention.
Fig. 5 is a three-dimensional exploded view of a continuously variable transmission according to embodiment 2 of the present invention.
Fig. 6 is a vehicle speed change diagram in the case of low-speed rapid acceleration according to embodiment 2 of the present invention.
Fig. 7 is a vehicle speed change diagram for the case of low-speed rapid acceleration of comparative example 2 of the present invention.
Wherein: 1, a driving shaft; 2, an active cam; 3-1, a coil spring; 3-2, a disc spring; 4, rolling bodies; 5, actively fixing a cone disc; 6, a steel flexible transmission element; 7, driving the cone disc; 8, a driven shaft; 9, driven fixed cone disc; 10, driven dynamic conical disks; 11, a disc spring seat; 201, the end section of the raceway or the pressing surface; 202, a pressing section of a raceway or pressing surface; 203, initial section of the raceway or pressing surface.
Detailed Description
The stepless speed changer is in friction transmission, the cam pressurizing mechanism needs to ensure that the flexible transmission element and the conical disc surface are always kept in a pressing state, in order to ensure the processing aspect and the contact strength of the flexible transmission element and the conical surface, the existing conical disc mostly adopts a straight bus conical disc, when the transmission ratio is changed, the flexible transmission element moves up and down along the conical disc surface to generate radial and axial displacement, and because the working radiuses of a driving shaft and a driven shaft are not completely the same in the speed ratio changing process, the length of the flexible transmission element is assumed to be constant, the outward movement or inward movement distance of the contact point of the flexible transmission element of the driving shaft and the outward movement or inward movement distance of the contact point of the flexible transmission element of the driven shaft are not the same, the flexible transmission element inevitably generates axial deflection in the speed changing process, as shown in figure 1, the compensating amount of the pressurizing mechanism caused by system deflection under different speed ratios can be changed, and the problem that along with the increase of the speed ratio range can be undoubtedly found, the amount of compensation increases. In practical situations, the amount of compensation required is greater due to system degeneration and elongation of the flexible transmission element. The axial force required by the transmission of the flexible transmission element is provided by the cam pressurizing mechanism, the smaller the included angle value between the vertical plane of the rotating central line of the conical disc and the raceway or pressurizing surface after being unfolded along the circumferential direction is, the larger the axial force can be provided, and the axial stroke amount which can be compensated by the cam is reduced, so that the circumferential waste is caused in the situation of power positive and negative asymmetry of the bidirectional cam pressurizing mechanism.
Example 1
As shown in fig. 2, the present embodiment provides a continuously variable transmission pressurized by a one-way cam, which includes a driving shaft, a driving cone disc set, a driven shaft, a driven cone disc set, a one-way cam pressurizing mechanism, and a steel flexible transmission element. The driving conical disc set comprises a driving fixed conical disc and a driving movable conical disc, the driven conical disc set comprises a driven fixed conical disc and a driven movable conical disc, and the driving conical disc set and the driven conical disc set clamp the steel flexible transmission element to work in a lubricating oil environment. The maximum value of the outer radius of the driving cone disc set is 109mm, the maximum value of the outer radius of the driven cone disc set is 109mm, the included angle between the conical surface generatrix of the driving cone disc set and the conical surface generatrix of the driven cone disc set of the continuously variable transmission and the vertical plane of the rotating center line of the conical discs is 11 degrees, and the back of the driving fixed cone disc is provided with a one-way cam pressurizing mechanism.
The one-way cam pressurizing mechanism comprises a driving cam, a driven cam, a rolling body and an elastic pressurizing element, wherein the driving cam is connected with a driving shaft through a spline, and the driven cam and the driving fixed cone disc are integrated and arranged on the back of the driving fixed cone disc. The end faces of the driving cam and the driven cam are respectively provided with 5 raceways or pressurizing faces which are uniformly distributed in the circumferential direction, the structure of the driving cam is shown in fig. 3, each raceway or pressurizing face comprises an initial section 201, a pressurizing section 202 and a termination section 203, the included angle between the pressurizing section and the vertical plane of the rotation center line of the conical disc is single, the end faces where the raceways or pressurizing faces of the driving cam and the driven cam are located are oppositely arranged, and the driving cam and the driven cam are connected through rolling bodies clamped between the raceways or pressurizing faces on the oppositely arranged end faces.
After the raceway or the pressurizing surface on the end surface of the driving cam is expanded along the circumferential direction, as shown in fig. 4, except for 2 parts of the initial section and the terminating sections 201 and 203 of the raceway or the pressurizing surface, the included angle between the other main pressurizing sections 202 and the vertical plane of the rotation center line of the conical disc is 6.8 degrees; after the roller path or the pressurizing surface on the end surface of the driven cam is expanded along the circumferential direction, except 2 parts of the initial section and the end sections 201 and 203 of the roller path or the pressurizing surface, the included angles between the other main pressurizing sections 202 and the vertical plane of the rotation center line of the conical disc are also 6.8 degrees, so that the requirement of meeting the requirement of the rotation center line of the conical disc is met
Figure BDA0003734198070000071
The requirements of (2).
The elastic pressurizing elements are 3-1 helical springs, the number of the helical springs is 3, the helical springs are annularly and uniformly distributed in the circumferential direction between the driving cam and the driven cam, the driving cam and the driven cam are abutted through the helical springs, and one end of each spring is abutted against the pressurizing driving camThe direction of a main pressurizing surface of the contact connection is the tangential direction of the rotation of the driving cam; the other end of the spring is in contact connection with a driven cam of the driving fixed cone disc, the direction of a main pressurizing surface of the spring is the tangential direction of the rotation of the driven cam, the maximum compression force of the single spiral spring is 0.17kN, and the requirement of the requirement on the contact of the other end of the spring and the driven cam of the driving fixed cone disc is met
Figure BDA0003734198070000072
The requirements of (1).
In order to ensure that the transmission is compact, the outer diameters of the driving cam and the driven cam are smaller than those of the driving cone disc set and the driven cone disc set, and the diameter of the corresponding roller path or the pressing surface of the embodiment in the circumferential direction is 120 mm.
In this embodiment, the rolling elements are preferably steel balls, and the diameter d of the steel balls is preferably 25mm, so that d is greater than or equal to 0.04 (R) max1 +R max2 ) The requirements of (1).
In this embodiment, preferably, the height of the rotating bus of the conical-disc convex conical surface relative to the connecting straight line at the two ends of the bus is higher, that is, in the same rotating plane where the rotating center line of the conical disc is located, the shortest distance between the tangent line of the rotating bus, which is parallel to the connecting straight line at the two ends of the rotating bus, and the connecting straight line at the two ends of the rotating bus and the diameter of the conical disc is greater than or equal to 1/200.
Comparative example 1
The stepless speed changer adopting bidirectional cam pressurization comprises a driving shaft, a driving cone disc set, a driven shaft, a driven cone disc set, a bidirectional cam pressurization mechanism and a steel flexible transmission element. The drive cam and the driven cam roller path or the pressurizing surface of the bidirectional cam pressurizing mechanism are of V-shaped roller path or V-shaped pressurizing surface structures and comprise a forward pressurizing section, a reverse pressurizing section, a transition section and a termination section which are connected with each other. The included angle between the forward pressurizing section and the vertical plane of the conical disc rotation center line is 6.8 degrees, and the included angle between the reverse pressurizing section and the vertical plane of the conical disc rotation center line is 6.8 degrees. The other arrangement is the same as in embodiment 1.
Compared with the continuously variable transmission of the embodiment 1, under the condition that the input torque is 630Nm, the length of the flexible transmission element is 939mm, the corresponding rigidity is 0.00092913KN/mm, the axial stroke compensation amount of the cam pressurizing mechanism of the embodiment 1 is 4.5mm, the axial stroke compensation amount of the cam pressurizing mechanism of the embodiment 1 is 3mm, when the speed ratio range is 5, the compensation amount of the pressurizing mechanism requirement caused by system deviation is 2mm, the tension of the flexible transmission element is 13.2KN, the contact point of the flexible transmission element of the driving shaft is outwards moved, the axial stroke of the corresponding cam roller path is required to be compensated for being more than 1mm, the flexible transmission element of the embodiment 1 is caused to skid, and the transmission reliability is reduced.
Example 2
A continuously variable transmission with one-way cam pressurization is shown in figure 5 and comprises a driving shaft, a driving conical disc set, a driven shaft, a driven conical disc set, a one-way cam pressurization mechanism and a steel flexible transmission element. The driving cone disc set comprises a driving fixed cone disc and a driving movable cone disc, the driven cone disc set comprises a driven fixed cone disc and a driven movable cone disc, and the driving cone disc set and the driven cone disc set clamp the steel flexible transmission element to work in a lubricating oil environment. The maximum value of the outer radius of the driving conical disc group is 109mm, the maximum value of the outer radius of the driven conical disc group is 109mm, the included angle between the conical surface generatrix of the driving conical disc group and the conical surface generatrix of the driven conical disc group of the continuously variable transmission and the vertical plane of the rotation center line of the conical discs is 11 degrees, and a one-way cam pressurizing mechanism is arranged on the back of the driving fixed conical disc.
The one-way cam pressurizing mechanism comprises a driving cam, a driven cam, a rolling body and an elastic pressurizing element, wherein the driving cam is connected with a driving shaft through a spline, and the driven cam and the driving fixed cone disc are integrated and arranged on the back of the driving fixed cone disc. The end faces of the driving cam and the driven cam are respectively provided with 5 roller paths or pressurizing faces which are uniformly distributed along the circumferential direction with the diameter of 200mm, the included angle between each roller path or pressurizing face and the vertical face of the rotation center line of the conical disc is single, the end faces where the roller paths or pressurizing faces of the driving cam and the driven cam are located are arranged oppositely, and the driving cam and the driven cam are connected through rolling bodies clamped between the roller paths or pressurizing faces on the end faces which are arranged oppositely.
After the raceway or the pressurizing surface on the end surface of the driving cam is expanded along the circumferential direction, the rest parts except 2 parts of the initial section and the final section 201 and 203 of the raceway or the pressurizing surface are mainly addedThe included angle between the pressing part 202 and the vertical plane of the rotation center line of the conical disc is 6.8 degrees; after the roller path or the pressurizing surface on the end surface of the driven cam is expanded along the circumferential direction, except 2 parts of the initial section and the end sections 201 and 203 of the roller path or the pressurizing surface, the included angle between the rest main pressurizing part 202 and the vertical plane of the rotation center line of the conical disc is also 6.8 degrees, so that the requirement of meeting the requirement of the rotation center line of the conical disc is met
Figure BDA0003734198070000091
The requirements of (1).
The elastic pressurizing element is a disc spring 3-2, the disc springs are 3 pieces, one end of an axial groove of the disc spring is abutted against the driving cam, the other end of the axial groove of the disc spring is placed in the disc spring seat 11 and abutted against the driving shaft through the disc spring seat, the direction of a main pressurizing surface of the disc spring is axial, and the total maximum compression force F is 1 16kN, satisfies
Figure BDA0003734198070000092
Figure BDA0003734198070000093
The requirements of (1).
In this embodiment, the rolling element is a steel ball, and the diameter d of the steel ball is 25mm, which satisfies d is not less than 0.04 (R) max1 +R max2 ) The requirements of (1).
The rotating bus of the conical disc convex conical surface is higher than the connecting straight line at the two ends of the bus, namely, in the same rotating plane where the rotating center line of the conical disc is located, the shortest distance between the tangent line of the rotating bus, which is parallel to the connecting straight line at the two ends of the rotating bus, and the connecting straight line at the two ends of the rotating bus is greater than or equal to 1/200 of the diameter of the conical disc.
Comparative example 2
The stepless speed changer adopting bidirectional cam pressurization comprises a driving shaft, a driving cone disc set, a driven shaft, a driven cone disc set, a bidirectional cam pressurization mechanism and a steel flexible transmission element. The drive cam and the driven cam rolling way or the pressurizing surface of the bidirectional cam pressurizing mechanism are in a V-shaped rolling way or V-shaped pressurizing surface structure (the lengths of two pressurizing sections are basically equal), and the bidirectional cam pressurizing mechanism comprises a forward pressurizing section, a reverse pressurizing section and a transition pressurizing section which are connected with each otherThe elastic pressurizing element is 3 disc springs, one end of an axial groove of each disc spring is abutted against the driving cam, the other end of the axial groove of each disc spring is placed in the disc spring seat and is abutted against the driving shaft through the disc spring seat, the direction of a main pressurizing surface of the disc spring seat is axial, and the total maximum compression force F is 1 4 kN. The other arrangement is the same as in example 2.
In the continuously variable transmission of the comparative example 2 and the embodiment 2, in the same road, the transmission is connected with a speed regulating motor, a rapid acceleration test (keeping the engine speed at 500rpm stable, rapidly increasing the throttle opening to 99% within 2s, and then rapidly releasing) is carried out under the condition of low speed, the speed change of the transmission in the embodiment 2 and the comparative example 2 is shown in fig. 6 and 7, for the embodiment 2, after the throttle is rapidly stepped on, the speed ratio of the transmission is steadily changed from large to small, corresponding to the steady increase of the rotation speed of the shaft II, and after the throttle is rapidly released, the speed ratio of the transmission is steadily changed from small to large, corresponding to the steady decrease of the rotation speed of the shaft II; in the comparative example 2, as shown in fig. 7, after the throttle is quickly stepped on, the speed ratio of the gearbox changes from large to small, and fluctuates at a certain frequency, corresponding to the fact that the rotating speed of the shaft II fluctuates at a certain frequency in the process of reaching the peak rotating speed, and after the throttle is quickly loosened, the speed ratio of the gearbox changes from small to large, corresponding to the fact that the rotating speed of the shaft II tends to steadily decrease after small oscillation at a certain frequency. It can thus be seen that example 2 has higher system reliability and overall lifetime than comparative example 2.

Claims (10)

1. A stepless speed changer pressurized by a one-way cam comprises a driving shaft, a driving fixed cone disc, a driving movable cone disc, a driven shaft, a driven fixed cone disc, a driven movable cone disc and a steel flexible transmission element, wherein the driving fixed cone disc and the driving movable cone disc form a driving cone disc group, the driven fixed cone disc and the driven movable cone disc form a driven cone disc group, and the driving cone disc group and the driven cone disc group work in an environment with lubricating oil through the clamped steel flexible transmission element; the method is characterized in that:
the stepless transmission also comprises a one-way cam pressurizing mechanism, and the one-way cam pressurizing mechanism is arranged on the back of the driving fixed cone disc and/or the driven fixed cone disc; the one-way cam pressurizing mechanism comprises a driving cam, a driven cam, a rolling body and an elastic pressurizing element, wherein the driving cam is connected with a driving shaft and/or a driven shaft in a mode of not allowing mutual rotation (such as direct fixed connection, keying, welding, press fitting, interference fit or bonding); the driven cam is connected with the driving fixed conical disc and/or the back surface of the driven fixed conical disc in a mode (such as direct fixed connection, key connection, welding, press fitting, interference fit or adhesion) that mutual rotation is not allowed; the end surfaces of the driving cam and the driven cam are respectively provided with n raceways or pressurizing surfaces which are uniformly distributed in the circumferential direction; the n rolling bodies are arranged in the roller path between the driving cam and the driven cam; wherein n is more than or equal to 3 and less than or equal to 9; the raceway comprises an initial section, a pressurizing section and a termination section after being expanded along the circumferential direction, the raceways or pressurizing surfaces of the driving cam and the driven cam are arranged oppositely, and the driving cam and the driven cam are connected through rolling bodies clamped between the oppositely arranged raceways or pressurizing surfaces;
the pressurizing section is a one-way pressurizing section, the pressurizing section is a three-dimensional curved surface which is constructed by the movement of a semicircular cross section consisting of two sections of non-concentric circular arcs along a trajectory line on a cylindrical surface which is parallel to the axis of the conical disk and takes the axis of the conical disk as the rotation center, the cylindrical surface where the trajectory line is positioned is unfolded into a plane, namely, an unfolding line of the trajectory line of the pressurizing section is unfolded, and the unfolding line of the trajectory line of the pressurizing section is a two-dimensional line section which changes monotonously.
2. The single-direction cam-pressurized continuously variable transmission according to claim 1, wherein the angle between the pressurized segment of the end surface of the drive cam after the raceway or pressurized surface is expanded in the circumferential direction and the vertical plane of the center line of rotation of the conical disk is α 1 (ii) a The included angle between the pressurizing section and the vertical plane of the rotation center line of the conical disc after the roller path or the pressurizing surface on the end surface of the driven cam is expanded along the circumferential direction is alpha 2 (ii) a Gamma is the included angle between the conical surface generatrix of the driving conical disk group and the driven conical disk group of the continuously variable transmission and the vertical surface of the rotating center line of the conical disk, or the included angle between the tangent line of the conical surface generatrix of the driving conical disk group and the driven conical disk group of the continuously variable transmission at the geometric midpoint and the vertical surface of the rotating center line of the conical diskDegree;
i max the maximum gear ratio is designed for the continuously variable transmission,
Figure FDA0003734198060000021
wherein R is Wmin1 The minimum working radius of the driving cone disk group is the minimum enveloping radius of a contact area of the cone disk and the steel flexible transmission element; r Wmax2 The maximum working radius of the driven cone disc group, namely the maximum enveloping radius of the contact area of the cone disc and the steel flexible transmission element, satisfies the following relationship:
Figure FDA0003734198060000022
Figure FDA0003734198060000023
3. the one-way cam-pressurized continuously variable transmission of claim 1, wherein a needle bearing is provided between the driving cone pulley set and/or the driven cone pulley set to which the driven cam is connected and the driving shaft and/or the driven shaft; elastic pressurizing elements are arranged between the driving shaft and/or the driven shaft and the driving cam and/or between the driven cam and the conical disc.
4. A one-way cam-pressurized continuously variable transmission as claimed in claim 3, wherein said elastic pressurizing member is a coil spring or said elastic pressurizing member is one or more disc springs, one axial end of said disc spring is in contact with said one-way cam pressurizing mechanism directly or indirectly, the other end of said disc spring is in contact with said driving shaft or driven shaft directly or indirectly, the main pressurizing direction of said disc spring is axial, and the total axial maximum thrust of said elastic pressurizing member is F 1 In units of kilonewtons (kN), R max1 Is the maximum value of the outer radius of the driving cone group and has the unit of mm, R max2 Of the outer radius of the driven cone-disc setThe maximum value is in mm, and gamma is an included angle between a conical surface generatrix of the driving conical disk group and a conical surface generatrix of the driven conical disk group of the continuously variable transmission and a vertical plane of a conical disk rotation central line, or an included angle between a tangent line of the conical surface generatrix of the driving conical disk group and the conical surface generatrix of the driven conical disk group of the continuously variable transmission at a geometric midpoint and a vertical plane of the conical disk rotation central line; t is the maximum torque input by the continuously variable transmission, and the unit is Newton-meter (N.m), so that the requirements of the continuously variable transmission are met
Figure FDA0003734198060000031
Figure FDA0003734198060000032
5. The single direction cam pressurized continuously variable transmission of claim 1, wherein said rolling elements are steel balls having a diameter d ≥ 0.04(R ≥ R) max1 +R max2 ) Wherein R is max1 Is the maximum value of the outer radius of a driving cone disc group of the continuously variable transmission, and the unit is mm and R max2 The maximum value of the outer radius of the driven cone pulley set of the continuously variable transmission is in mm.
6. The single direction cam pressurized variable transmission of claim 1, wherein the surface hardness of the raceway of the cam is equal to or greater than HRC 56.
7. The one-way cam-pressurized continuously variable transmission of claim 1, wherein the surface hardness of the rolling elements is HRC58 or more.
8. A power machine characterized by using a continuously variable transmission pressurized by a one-way cam according to any one of claims 1 to 7.
9. The power machine of claim 8, wherein the power machine is a flight machine, an electric power generation machine, or an agricultural power machine.
10. The power machine of claim 9, wherein the agricultural power machine is a tractor.
CN202210791972.1A 2022-07-07 2022-07-07 One-way cam pressurized continuously variable transmission Pending CN115076313A (en)

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