Long-life, impact-resistant cam pressure mechanism and continuously variable transmission

Abstract

The present invention belongs to the field of transmissions, and specifically relates to a long-life, impact-resistant cam pressurizing mechanism and a continuously variable transmission using such a pressurizing mechanism. By improving the specific arrangement of components such as the cam raceway, rolling body and elastic pressurizing element, the cam operating point switching is made more stable. Compared with traditional cam pressurizing mechanisms, it can better buffer the drastic and repeated changes in load, and the pressurizing mechanism is more stable and reliable.

Description

Technical Field

[0001] The invention belongs to the field of power mechanical transmissions, and in particular relates to a long-life impact-resistant cam pressurizing mechanism and a continuously variable transmission using the cam pressurizing mechanism. Background Art

[0002] The main operating principle of a cone-disc continuously variable transmission (CVT) is to transmit power through a friction pair consisting of a cone-disc and a flexible transmission element. A pressure mechanism maintains pressure between the flexible transmission element and the cone-disc, thereby ensuring the friction required for power transmission. Since the early 21st century, a series of electromechanically controlled cone-disc CVTs have matured and are widely used in road, vehicle, and general machinery applications due to their low cost, high efficiency, and high reliability.

[0003] Chinese patent publication CN110762174A discloses a cam-pressurized cone-disc continuously variable transmission. This includes a cam pressurizing mechanism with a V-groove structure on the fixed cone. The angle and relationship between the pressurizing mechanism and related components are set to improve the system's dynamic response. This technical solution features identical designs for the forward and reverse pressurizing sections or surfaces of the V-groove, making it suitable for power machines with identical forward and reverse external characteristic curves. However, for normally operating single-direction power machines such as diesel and gasoline engines, the reverse pressurizing section is primarily caused by backdraft. Designing the forward and reverse pressurizing sections identically for the V-groove structure creates redundancy. Furthermore, under conditions of frequent switching between forward and reverse pressurization, this unsuitable structure can lead to increased wear on the cam groove, which in turn affects wear on the cone and chain, shortening the system life. Summary of the Invention

[0004] In view of the above technical problems, the purpose of the present invention is to provide a cam pressurizing mechanism that is suitable for frequent forward and reverse pressurization switching, has a long service life and high reliability, and a continuously variable transmission using this structure.

[0005] This is achieved through the following technical means:

[0006] A long-life, impact-resistant cam pressure mechanism, the cam pressure mechanism being arranged on the back side of the driving fixed cone plate and / or the driven fixed cone plate of a continuously variable transmission, the cam pressure mechanism comprising a driving cam, a driven cam, a rolling body and an elastic pressure element, the driving cam being connected to the driving shaft and / or the driven shaft of the continuously variable transmission in a manner that does not allow mutual rotation; the driven cam being connected to the back side of the driving fixed cone plate and / or the driven fixed cone plate of the continuously variable transmission in a manner that does not allow mutual rotation; an elastic pressure element being provided between the driving shaft and / or the driven shaft of the continuously variable transmission and the driving cam, and / or between the driven cam and the driving fixed cone plate and / or the driven fixed cone plate of the continuously variable transmission; and n circumferentially uniformly distributed rolling paths or pressure surfaces being respectively provided on the end surfaces of the driving cam and the driven cam.

[0007] The raceways or pressure surfaces of the active cam and the driven cam are arranged opposite to each other, and the active cam and the driven cam are connected by rolling bodies clamped between the oppositely arranged raceways or pressure surfaces; the raceways include a positive pressure section, a transition section, a negative pressure section and a termination section, and the positive pressure section, the transition section and the negative pressure section are three-dimensional surfaces constructed by moving along a straight line parallel to the axis of the cone disk as the generatrix and a trajectory line on a cylindrical surface with the axis of the cone disk as the rotation center after the cross-sections of the positive pressure section, the transition section and the negative pressure section have the same shape (the same shape is, for example, a semicircle composed of two non-concentric arcs or a semi-ellipse composed of two non-concentric arcs, etc.); the trajectory line is divided into three parts: the positive pressure section trajectory line, the transition section trajectory line and the negative pressure section trajectory line. After the cylindrical surface where the trajectory line is located is unfolded into a plane, the three parts of the positive pressure section trajectory line, the transition section trajectory line and the negative pressure section trajectory line are unfolded into three line segments: the positive pressure section trajectory line unfolding line, the transition section trajectory line unfolding line and the negative pressure section trajectory line unfolding line.

[0008] The transition segment trajectory expansion line is a curve including a monotonically rising section and a monotonically falling section.

[0009] The forward pressurization segment trajectory expansion line and the reverse pressurization segment trajectory expansion line are respectively a monotonically rising line segment and a monotonically descending line segment, and the forward pressurization segment trajectory expansion line and the reverse pressurization segment trajectory expansion line are respectively connected to the transition segment trajectory expansion line in a tangent form.

[0010] Preferably, n rolling bodies are provided in n circumferentially uniformly distributed raceways respectively provided on the end faces of the driving cam and the driven cam, and the n rolling bodies are clamped between the driving cam and the driven cam; n ≥ 3; the surface hardness of the raceways is greater than or equal to HRC56; the surface hardness of the rolling bodies is greater than or equal to HRC58.

[0011] Preferably, the length of the forward pressurizing section trajectory is not equal to the length of the reverse pressurizing section trajectory (preferably, the length of the longer trajectory is 1.05 to 1.8 times the length of the shorter trajectory).

[0012] Preferably, the rolling element is a steel ball, the diameter of which is d≥0.06(R max1 +R max2 ), where R max1 is the maximum outer radius of the active cone-disc group of the continuously variable transmission, R max2 It is the maximum value of the outer radius of the driven cone-disc group of the continuously variable transmission.

[0013] As a preference, the direction parallel to the cone axis on the unfolding plane is the y-axis, the direction perpendicular to the y-axis on the unfolding plane is the x-axis, and the line segment consisting of the unfolding line of the positive pressurization section trajectory, the unfolding line of the transition section trajectory, and the unfolding line of the reverse pressurization section trajectory is expressed as a function f(x). The first-order derivative of f(x) is It is continuous everywhere within the range of the expansion line of the forward pressurization section trajectory line, the expansion line of the transition section trajectory line and the expansion line of the reverse pressurization section trajectory line. Preferably, the third-order derivative f″′(x) of f(x) is continuous everywhere within the range of the expansion line of the forward pressurization section trajectory line, the expansion line of the transition section trajectory line and the expansion line of the reverse pressurization section trajectory line.

[0014] Preferably, the theoretical curvature radius of f(x) at any position within the range of the unfolding line of the forward pressurizing section trajectory, the unfolding line of the transition section trajectory and the unfolding line of the reverse pressurizing section trajectory is greater than or equal to the radius of the rolling body.

[0015] Preferably, the cross-section of the movement along the forward pressurization section trajectory line, the transition section trajectory line and the reverse pressurization section trajectory line includes two non-concentric arcs, the curvature radius of the two arcs is equal, and the curvature radius of the arc is R, satisfying R≥(d+0.25mm) / 2, where d is the diameter of the rolling body.

[0016] A long-life, impact-resistant, cam-pressurized continuously variable transmission, the continuously variable transmission comprising a driving shaft, a driving cone disc group, a driven shaft, a driven cone disc group, a cam pressurizing mechanism, and a steel flexible transmission element, the cam pressurizing mechanism being the above-mentioned long-life, impact-resistant cam pressurizing mechanism, the driving cone disc group comprising a driving fixed cone disc and a driving driven cone disc, the driven cone disc group comprising a driven fixed cone disc and a driven driven cone disc, the cam pressurizing mechanism being provided on the back side of the driving cone disc group and / or the driven cone disc group, a needle bearing being provided between the driving cone disc group and / or the driven cone disc group connected to the driven cam and the driving shaft and / or the driven shaft; and an elastic pressurizing element being provided between the driving shaft and / or the driven shaft and the driving cam, and / or between the driven cam and the driving fixed cone disc and / or the driven fixed cone disc.

[0017] As a preference, the angle between the positive pressure section after the raceway or pressure surface on the end face of the active cam is expanded in the circumferential direction and the vertical plane of the cone disk rotation centerline is α 11 The angle between the reverse pressure section after the raceway or pressure surface on the end face of the active cam is expanded in the circumferential direction and the vertical plane of the cone disk rotation centerline is α 12 The angle between the positive pressure section and the vertical plane of the cone disk rotation centerline after the raceway or pressure surface on the end face of the driven cam is expanded in the circumferential direction is α 21 The angle between the reverse pressure section after the raceway or pressure surface on the end face of the driven cam is expanded in the circumferential direction and the vertical plane of the cone disk rotation centerline is α 22 ; and satisfy:

[0018]

[0019]

[0020]

[0021]

[0022] γ is the angle between the cone surface generatrix of the driving cone disc group and the driven cone disc group of the continuously variable transmission and the perpendicular plane of the cone disc rotation centerline, or the angle between the tangent line of the cone surface generatrix of the driving cone disc group and the driven cone disc group of the continuously variable transmission at the geometric midpoint and the perpendicular plane of the cone disc rotation centerline; i max It is the maximum transmission ratio of the continuously variable transmission.

[0023] Preferably, the elastic pressure element is one or more disc springs, one axial end of the disc spring is in direct or indirect contact with the long-life impact-resistant cam pressure mechanism, and the other end is in direct or indirect contact with the driving shaft or the driven shaft. The main pressure direction of the disc spring is axial, and the total maximum thrust of the disc spring is F2, in kilonewtons (kN), meeting Where T is the maximum input torque of the continuously variable transmission, in Newton meters (N m), and R max1 is the maximum outer radius of the active cone-disc group of the continuously variable transmission, R max2 is the maximum outer radius of the driven cone-disc assembly of the continuously variable transmission. is the designed maximum transmission ratio of the continuously variable transmission.

[0024] The so-called "continuous" in the present invention means that the derivative of the function is within the range of the expansion line and no step occurs at any point.

[0025] The technical effects of the present invention are:

[0026] 1. The present invention can greatly reduce the impact of the rolling body on the cam raceway, thereby reducing the wear of the cam raceway, by specifically configuring the cam pressurizing mechanism, configuring the connection mode between the forward pressurizing section, the reverse pressurizing section and the transition section, and especially configuring the structural features of the transition section.

[0027] 2. The present invention specifically sets the physical dimensions and surface hardness of the contact pair of the rolling element and the cam raceway, thereby ensuring the contact strength and contact life of the rolling contact pair.

[0028] 3. In order to ensure the reliability of the friction-type continuously variable transmission and reduce the wear of the chain, cam raceway, roller and other parts of the system caused by excessive pressure, the present invention optimizes the pressure angle. The pressure angle determined by the formula set by the present invention will, on the one hand, reduce system wear and improve system efficiency; on the other hand, it ensures the realization of the pressure function and improves the reliability of the system.

[0029] 4. The present invention specifically defines the elastic pressure element, making it more suitable for the specific working mode of the present invention. On the one hand, it ensures sufficient preload under impact load and reduces the wear of the system due to elastic deformation and sliding friction under impact load. On the other hand, it reduces unnecessary preload under relatively stable load, thereby increasing the fatigue life of the system and reducing system wear.

[0030] 5. The present invention makes the transition curve smooth by specifically setting its shape (expressed as the continuity of first-order and specific higher-order derivatives), ensuring that when switching between positive and negative loads (such as torque and steering), the maximum movement speed and movement acceleration of the rolling body will not reach a large extreme value, thereby reducing the impact on the raceway and improving the life of the system.

[0031] 6. The present invention sets the length of the reverse cam roller shorter than that of the forward cam roller, and cooperates with the elastic pressure element and the pressure characteristics of the elastic pressure element to effectively utilize the cam roller to form a torsional vibration reduction effect, thereby reducing the impact of the impact load on the roller; at the same time, the total length of the cam roller is reduced, so that more cam rollers can be arranged, effectively dispersing the load and improving the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A three-dimensional diagram of a continuously variable transmission according to an embodiment of the present invention.

[0033] Figure 2 This is a planar expansion diagram of a cylindrical surface where the driving cam or driven cam raceway or the pressure surface is located according to an embodiment of the present invention.

[0034] Figure 3It is a cross-sectional view of the trajectory motion of the forward pressurization section, transition section and reverse pressurization section of the present invention.

[0035] Wherein: 1. driving shaft, 2. elastic pressure element, 3. driving cam, 4. rolling element, 5. driving fixed cone, 6. steel flexible transmission element, 7. driving movable cone, 8. driven shaft, 9. driven fixed cone, 10. driven movable cone, 11. disc spring seat, 301. unfolding line of the forward pressure section trajectory, 302. unfolding line of the transition section trajectory, 303. unfolding line of the reverse pressure section trajectory, 304. unfolding line of the terminal section trajectory; R. radius of curvature of the cross-section arc of the trajectory motion. DETAILED DESCRIPTION

[0036] A cone-disc continuously variable transmission (CVT) consists of a driving shaft, a driving cone-disc assembly, a driven shaft, a driven cone-disc assembly, a pressure mechanism, and a flexible transmission element. The pressure mechanism provides the axial force required to clamp the flexible transmission element. The cam pressure mechanism, through the movement of the rolling elements on a given angle of the raceway or pressure surface, can provide varying axial forces depending on the engine's output torque, achieving higher efficiency. As a key component of the CVT, the contact strength between the rolling elements and the raceway must be ensured while ensuring smooth rolling motion. For single-rotational power machines like diesel and gasoline engines, forward and reverse travel is primarily achieved through the shift mechanism. Due to back-drag, the requirements for the reverse pressure section or pressure surface differ from those for the forward section or pressure surface, resulting in frequent and short switching times. This switching process is prone to sudden speed changes, altered contact conditions, and roller jumps.

[0037] Example 1

[0038] like Figure 1 The long-life, impact-resistant cam pressure mechanism shown is arranged on the back of the active cone disc group. The active cone disc group includes an active fixed cone disc and an active movable cone disc, and the driven cone disc group includes a driven fixed cone disc and a driven movable cone disc. The active cam is connected to the active shaft in a manner that does not allow mutual rotation, and the driven cam is connected to the active fixed cone disc in a manner that does not allow mutual rotation. The cam pressure mechanism includes an active cam, a driven cam, a rolling body, and an elastic pressure element.

[0039] The raceways or pressure surfaces of the active cam and the driven cam are arranged opposite to each other, and the active cam and the driven cam are connected by a rolling body clamped between the oppositely arranged raceways; the raceways, when unfolded in the circumferential direction, include a positive pressure section, a transition section, a negative pressure section, and a terminal section. The positive pressure section, transition section, and negative pressure section are three-dimensional curved surfaces constructed by moving along a trajectory line on a cylindrical surface parallel to the axis of the cone disk and with the cone disk axis as the center of rotation, with the same cross section; the trajectory line is divided into three parts: the positive pressure section trajectory line, the transition section trajectory line, and the negative pressure section trajectory line. Figure 2As shown, after the cylindrical surface where the trajectory line is located is unfolded into a plane, the three parts of the forward pressurization segment trajectory line, the transition segment trajectory line and the reverse pressurization segment trajectory line are unfolded into three two-dimensional line segments: the forward pressurization segment trajectory line unfolding line, the transition segment trajectory line unfolding line and the reverse pressurization segment trajectory line unfolding line.

[0040] The unfolding line of the transition segment trajectory is a two-dimensional curve including a monotonically rising section and a monotonically falling section, and the monotonically rising and monotonically falling curves are connected in a tangent form.

[0041] The forward pressurization segment trajectory line expansion line and the reverse pressurization segment trajectory line expansion line are respectively a monotonically rising two-dimensional line segment and a monotonically descending two-dimensional line segment, and the forward pressurization segment trajectory line expansion line and the reverse pressurization segment trajectory line expansion line are respectively connected to the transition segment trajectory line expansion line in a tangent form.

[0042] In this embodiment, five rolling bodies are provided in five circumferentially evenly distributed raceways respectively provided on the end faces of the driving cam and the driven cam, and the five rolling bodies are clamped between the driving cam and the driven cam; the surface hardness of the raceways is greater than or equal to HRC56; the surface hardness of the rolling bodies is greater than or equal to HRC58.

[0043] In this embodiment, the length of the forward pressurization section trajectory is not equal to the length of the reverse pressurization section trajectory, and the length of the forward pressurization section trajectory is 1.31 times the length of the reverse pressurization section trajectory.

[0044] This embodiment features a long-life, impact-resistant continuously variable transmission with a maximum transmission ratio of 4. Needle roller bearings are installed between the driving fixed cone, which is connected to the driven cam, and the driving shaft. Both the driving and driven cone assemblies have an outer radius of 109 mm. Five circumferentially evenly spaced raceways are located on the end faces of each cam.

[0045] The rolling element is a steel ball with a diameter of d=30 mm, satisfying the formula d≥0.06(R max1 +R max2 ) requirements.

[0046] The included angle between the positive pressurizing section after the raceway or pressurizing surface on the end face of the active cam is expanded in the circumferential direction and the vertical plane of the cone disc rotation centerline is 6.8°; the included angle between the negative pressurizing section after the raceway or pressurizing surface on the end face of the active cam is expanded in the circumferential direction and the vertical plane of the cone disc rotation centerline is 6.8°; the included angle between the positive pressurizing section after the raceway or pressurizing surface on the end face of the driven cam is expanded in the circumferential direction and the vertical plane of the cone disc rotation centerline is 6.8°; the included angle between the generatrix of the cone surface of the cone disc and the vertical plane of the cone disc rotation centerline is 11°, and each angle satisfies The maximum transmission ratio is defined as where R Wmin1 is the minimum working radius of the active cone disc group, that is, the minimum envelope radius of the contact area between the cone disc and the steel flexible transmission element; R Wmax2 It is the maximum working radius of the driven cone disc group, that is, the maximum envelope radius of the contact area between the cone disc and the steel flexible transmission element.

[0047] The elastic pressure element of this embodiment is a three-piece disc spring. One axial end of the disc spring is in direct contact with the long-life and impact-resistant cam pressure mechanism, and the other end is in direct contact with the driving shaft or the driven shaft. The main pressure direction of the disc spring is axial. The maximum compression force of the disc spring at the maximum working stroke is 25KN, which meets the requirements. requirements.

[0048] In this embodiment, the direction parallel to the cone axis on the expansion plane is defined as the y-axis, and the direction perpendicular to the y-axis on the expansion plane is defined as the x-axis. The three two-dimensional line segments, namely, the expansion line of the forward pressurization segment trajectory, the expansion line of the transition segment trajectory, and the expansion line of the reverse pressurization segment trajectory, are represented as a line segment function f(x). The third-order derivative f″′(x) of f(x) is continuous throughout the expansion range of the forward pressurization segment trajectory, the expansion line of the transition segment trajectory, and the reverse pressurization segment trajectory.

[0049] like Figure 3 As shown, the cross sections of the forward pressurizing section, transition section, and reverse pressurizing section comprise two non-concentric arcs, the arcs have equal curvature radii, and the arc curvature radius R=16 mm, meeting the requirement of R≥(d+0.25 mm) / 2.

[0050] Comparative Example 1

[0051] The other settings of this comparative example are the same as those of Example 1, except that the diameter d of the steel ball is 10 mm, R max1 109mm, R max2 is 109 mm, which does not satisfy the formula d≥0.04(Rmax1 +R max2 ) requirement, corresponding to an arc curvature radius of R = 10.5mm. This satisfies the requirement of R ≥ (d + 0.25mm) / 2. Comparative torque testing under the same conditions as Example 1 revealed that, given the outer radii of the driving and driven cone disc groups capable of transmitting torque, the contact strength between the cam and the raceway in this comparative example was insufficient. Compared to Example 1, this comparative example failed to meet the strength requirements, resulting in indentations on the raceway surface.

[0052] Comparative Example 2

[0053] The other settings of this comparative example are the same as those of Example 1, except that the length of the trajectory line of the forward pressurizing section is equal to the length of the trajectory line of the reverse pressurizing section. Through the comparative impact load test under the same conditions as Example 1, it is found that the cam raceway of this comparative example is limited by the circumferential size under the condition of ensuring the transmission torque (given angle), and it is easy to cause the steel ball to roll over the raceway surface and fall out under the positive impact load. Compared with Example 1, this comparative example cannot adapt to the working conditions of frequent unidirectional power impact loads and has low reliability.

[0054] Comparative Example 3

[0055] The other settings of this comparative example are the same as those of Example 1, except that the third-order derivative f″′(x) of f(x) is discontinuous within the expansion range of the trajectory line of the forward pressurization section, the expansion line of the transition section trajectory and the expansion range of the trajectory line of the reverse pressurization section. Through the comparative test of frequent rapid deceleration under the same conditions as Example 1, it is found that the speed of the power source of this comparative example and Example 1 will be increased during the rapid deceleration process, causing back-dragging, and the forward and reverse pressurization are frequently switched. During the switching process of this comparative example, the contact characteristics of the steel ball and the cam raceway surface are converted from two-point contact to four-point contact, which will generate infinite acceleration corresponding to infinite force, resulting in excessive vibration. Compared with Example 1, this comparative example cannot adapt to complex operating conditions and the cam raceway is worn.

[0056] Comparative Example 4

[0057] The other settings of this comparative example are the same as those of Example 1, except that the arc curvature radii are not equal, specifically, the arc curvature radii R1 = 16 mm, R2 = 17 mm. Through the durability comparison test under the same conditions as Example 1, it was found that the cam raceway surface contact area of ​​this comparative example was out of tolerance, the cam was overloaded during the pressurization process, and the unilateral contact strength of the steel ball and raceway contact point was insufficient. Compared with Example 1, the life and reliability of this comparative example were low, and indentations appeared on the unilateral raceway surface.

[0058] Comparative Example 5

[0059] The other configurations of this comparative example are the same as those of Example 1, except that the radius of curvature of the arc, R = 15.1 mm. This does not meet the requirement of R ≥ (d + 0.25 mm) / 2. Comparative impact load tests under the same conditions as Example 1 revealed that this comparative example easily causes the steel ball to become stuck and unable to apply pressure, resulting in poor followability of the pressurizing cam mechanism and frequent system slippage. Compared to Example 1, this comparative example has low reliability, is unable to adapt to impact loads, and exhibits wear on the raceway surface.

[0060] Comparative Example 6

[0061] The other settings of this comparative example are the same as those of Example 1, except that the maximum compression force of the disc spring at the maximum working stroke is 6KN, which does not meet the requirements. Through the comparative test of frequent rapid deceleration under the same conditions as Example 1, it was found that the chain slipped during the axial feeding of the pressurized cam of this comparative example. Compared with Example 1, the service life of this comparative example was shortened and the flexible transmission element was severely worn.

Claims

1. A long-life, impact-resistant cam pressurizing mechanism, characterized by: A cam pressure mechanism is disposed on the backside of the driving fixed cone and / or driven fixed cone of the continuously variable transmission, and includes a driving cam, a driven cam, a rolling element, and an elastic pressure element. The driving cam is connected to the driving shaft and / or driven shaft of the continuously variable transmission in a manner that does not allow for mutual rotation; the driven cam is connected to the backside of the driving fixed cone and / or driven fixed cone in a manner that does not allow for mutual rotation; an elastic pressure element is disposed between the driving shaft and / or driven shaft and the driving cam, and / or between the driven cam and the driving fixed cone and / or driven fixed cone; and n circumferentially uniformly distributed raceways are disposed on the end faces of the driving cam and the driven cam, respectively. The raceways of the active cam and the driven cam are arranged relative to each other, and the active cam and the driven cam are connected by the rolling elements clamped between the raceways; the raceways include a positive pressure section, a transition section, a reverse pressure section and a termination section, and the positive pressure section, the transition section and the reverse pressure section are three-dimensional surfaces constructed by the movement of the track line on the cylindrical surface with a straight line parallel to the axis of the cone as the generatrix and the axis of the cone as the center of rotation; the track line is divided into three parts: the positive track line, the transition track line and the reverse track line. After the cylindrical surface is unfolded into a plane, the positive trajectory line, transition trajectory line, and reverse trajectory line are unfolded into three line segments: the positive unfolding line, transition unfolding line, and reverse unfolding line. The transition unfolding line is a curve consisting of a monotonically rising segment and a monotonically falling segment. The positive unfolding line and reverse unfolding line are respectively a monotonically rising segment and a monotonically falling segment, and the positive unfolding line and reverse unfolding line are respectively tangent to the transition unfolding line. The lengths of the positive trajectory line and the reverse trajectory line are unequal, and the length of the longer trajectory line is 1.05 to 1.8 times that of the shorter trajectory line. The surface hardness of the raceway is greater than or equal to HRC56; the surface hardness of the rolling element is greater than or equal to HRC58.

2. The long-life impact-resistant cam pressing mechanism according to claim 1, characterized in that: N rolling bodies are arranged in n circumferentially uniformly distributed raceways respectively arranged on the end faces of the driving cam and the driven cam, and the n rolling bodies are clamped between the driving cam and the driven cam; the n is ≥3.

3. The long-life impact-resistant cam pressurizing mechanism according to any one of claims 1 to 2, characterized in that: The rolling element is a steel ball, the diameter of which is d≥ ,in is the maximum outer radius of the active cone disc group of the continuously variable transmission, It is the maximum value of the outer radius of the driven cone-disc group of the continuously variable transmission.

4. The long-life impact-resistant cam pressing mechanism according to claim 1, characterized in that: The direction parallel to the cone axis on the expansion plane is the y-axis, the direction perpendicular to the y-axis on the expansion plane is the x-axis, and the line segment composed of the positive expansion line, the transition expansion line and the reverse expansion line is expressed as the function f(x). The first derivative of f(x) is The third derivative of f(x) is continuous within the range of the positive expansion line, transition expansion line and reverse expansion line. It is continuous everywhere within the range of the positive expansion line, transition expansion line and reverse expansion line.

5. The long-life impact-resistant cam pressing mechanism according to claim 4, characterized in that: The theoretical curvature radius of f(x) at any position within the positive development line, the transition development line and the reverse development line is greater than or equal to the radius of the rolling element.

6. The long-life impact-resistant cam pressing mechanism according to claim 1, characterized in that: The cross section of the movement along the positive trajectory line, transition trajectory line and reverse trajectory line includes two non-concentric arcs, the curvature radius of the two arcs is equal, and the curvature radius of the arc is R, satisfying R≥(d+0.25mm) / 2, where d is the diameter of the rolling element.

7. A long-life, impact-resistant, cam-pressurized continuously variable transmission, characterized by: The continuously variable transmission includes a driving shaft, a driving cone disc group, a driven shaft, a driven cone disc group, a cam pressing mechanism, and a steel flexible transmission element. The cam pressing mechanism is the long-life, impact-resistant cam pressing mechanism according to any one of claims 1 to 6. The driving cone disc group includes a driving fixed cone disc and a driving driven cone disc, and the driven cone disc group includes a driven fixed cone disc and a driven driven cone disc. The cam pressing mechanism is provided on the back of the driving cone disc group and / or the driven cone disc group. A needle bearing is provided between the driving cone disc group and / or the driven cone disc group connected to the driven cam and the driving shaft and / or the driven shaft; and an elastic pressing element is provided between the driving shaft and / or the driven shaft and the driving cam, and / or between the driven cam and the driving fixed cone disc and / or the driven fixed cone disc.

8. The long-life, shock-resistant, cam-loaded continuously variable transmission according to claim 7, wherein: The angle between the positive pressure section after the raceway on the end face of the active cam is expanded in the circumferential direction and the vertical plane of the cone disk rotation centerline is α 11 The angle between the reverse pressure section and the vertical plane of the cone disk rotation centerline after the raceway on the active cam end surface is expanded in the circumferential direction is α 12 The angle between the positive pressure section and the vertical plane of the cone disk rotation centerline after the raceway on the end face of the driven cam is expanded in the circumferential direction is α 21 The angle between the reverse pressure section and the vertical plane of the cone disk rotation centerline after the raceway on the end face of the driven cam is expanded in the circumferential direction is α 22 ; and satisfy: ; ; ; γ is the angle between the cone surface generatrix of the driving cone disc group and the driven cone disc group of the continuously variable transmission and the vertical plane of the cone disc rotation centerline, or the angle between the tangent line of the cone surface generatrix of the driving cone disc group and the driven cone disc group of the continuously variable transmission at the geometric midpoint and the vertical plane of the cone disc rotation centerline; It is the maximum transmission ratio of the continuously variable transmission.

9. The long-life, shock-resistant, cam-loaded continuously variable transmission according to claim 8, characterized in that: The elastic pressure element is one or more disc springs, one axial end of the disc spring is in direct or indirect contact with the long-life impact-resistant cam pressure mechanism, and the other end is in direct or indirect contact with the driving shaft or the driven shaft. The main pressure direction of the disc spring is axial, and the total maximum thrust of the disc spring is F2, in kilonewtons, meeting , where T is the maximum input torque of the continuously variable transmission, in Newton meters.

Images