Transmission

Abstract

The transmission comprises a multi-stage speed change assembly, a differential assembly, an upper box body and a lower box body, the upper box body and the lower box body are connected, the multi-stage speed change assembly is arranged in the upper box body, the upper half portion of the differential assembly is arranged in the lower portion of the upper box body, and the lower half portion of the differential assembly is arranged in the lower box body. A final-stage gear of the multi-stage speed change assembly is meshed with a driven gear of the differential mechanism assembly to achieve driving. The plane where the cross shaft of the differential mechanism assembly is located serves as a datum plane, the plane where the driven gear is located is parallel to but offset relative to the datum plane, an outer shell of the differential mechanism assembly is also offset relative to the datum plane, and the offset direction of the outer shell is the same as that of the driven gear. On one hand, the problem that the bottom under the speed reducer protrudes and conflicts with an installation space is solved; on the other hand, the low-noise requirement can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical transmission, in particular to a transmission. Background Art

[0002] Transmissions are widely used in various industries, such as electric vehicles. Chinese Patent Publication No. CN 210978405 discloses a two-speed reducer for new energy vehicles. The reducer comprises an input shaft assembly, an intermediate shaft assembly, a differential assembly, a shift fork, a shift lever, and a shift motor. The input shaft assembly, intermediate shaft assembly, and differential assembly are connected to the housing via ball bearings at each end, and power is transmitted through gear meshing. The front end of the input shaft assembly is designed with internal splines for connection to the vehicle's power motor. The side gears at each end of the differential also have internal splines for connection to the drive shafts of the vehicle's left and right wheels. The intermediate shaft is designed with two idler gears and a synchronizer, enabling gear shifting based on the vehicle's driving conditions. The shift motor and the shift lever transmit power through gear meshing. The shift lever and the shift fork interact with each other via a shift knob, converting the shift lever's rotational motion into the up-and-down reciprocating motion of the shift fork. This achieves both power transmission and gear shifting in the reducer.

[0003] Common transmission mechanisms utilize a package-within-a-package design, where the differential assembly housing is enclosed within the transmission's outer housing. The outer housing is typically formed by two interlocking halves, with the interlocking surface largely aligning with the plane of the differential's cross-shaft. The two halves, along with the differential assembly, maintain a roughly symmetrical interlocking surface. However, as different industries demand different transmission stages and require smooth, low-noise transmissions, the number of gears and shafts integrated within the transmission has increased, leading to increased size. This often results in a mismatch between the transmission and the installation space.

[0004] This patent proposes a transmission precisely to solve the installation layout problem, which can be widely used as a transmission device in various industries such as electric two-wheeled vehicles, three-wheeled vehicles, and four-wheeled vehicles. Utility Model Content

[0005] The utility model provides a transmission, which solves the problem in the prior art that the transmission often fails to match the installation space layout.

[0006] In order to solve the above-mentioned technical problems, the technical solution of the present utility model is:

[0007] A transmission comprises a multi-speed transmission assembly and a differential assembly, as well as an upper case body and a lower case body connected thereto, wherein the multi-speed transmission assembly is arranged in the upper case body, the upper half of the differential assembly is arranged in the lower part of the upper case body, and the lower half of the differential assembly is arranged in the lower case body, and the final gear of the multi-speed transmission assembly is meshed with the driven gear of the differential assembly to achieve drive; with the plane where the cross shaft of the differential assembly is located as the reference plane, the plane where the driven gear is located is parallel to but offset from the reference plane, and the outer housing of the differential assembly is also offset from the reference plane and the offset direction is the same as that of the driven gear.

[0008] Preferably, the outer housing of the differential assembly comprises a left housing and a right housing that are connected, and a connection surface between the left housing and the right housing coincides with the reference plane.

[0009] Preferably, the driven gear and the right housing are both arranged on the right side of the reference plane, and the half-shaft gear located on the right side of the reference plane in the differential assembly is connected to the output shaft; the left housing and the right housing are respectively connected between the upper and lower housings through bearings.

[0010] Preferably, the differential assembly further comprises a counterweight block arranged on the offset side of the driven gear.

[0011] Preferably, the counterweight block and the driven gear are an integral structure, and the counterweight block adopts a mounting step structure for connecting to the outer housing of the differential assembly.

[0012] Preferably, when the multi-stage speed change assembly is a three-stage reducer, the multi-stage speed change assembly includes, from top to bottom, a first-stage gear shaft assembly, a second-stage gear shaft assembly and a third-stage gear shaft assembly, the first-stage gear shaft assembly is spline-connected to the output shaft of the external power source, the first-stage gear shaft assembly and the second-stage gear shaft assembly, the second-stage gear shaft assembly and the third-stage gear shaft assembly are driven by gear meshing, the gear installed on the third-stage gear shaft assembly is a low-speed gear that meshes with the driven gear to drive the driven gear to rotate, and the axes of the first-stage gear shaft assembly, the second-stage gear shaft assembly, the third-stage gear shaft assembly and the driven gear are all on the same plane.

[0013] Preferably, the gears of the three-stage reducer and the driven gears are all helical gears or cylindrical gears.

[0014] Preferably, the upper box body is provided with a mounting platform facing the lower box body and a mounting cover facing the external power source. The mounting cover is formed by extending from the edge of the upper box body where the first-stage gear shaft assembly and the second-stage gear shaft assembly are located. The mounting platform, the mounting cover and the upper box body are an integral one-piece structure.

[0015] Preferably, the mounting cover is on the same side as the driven gear.

[0016] Compared with the prior art, the beneficial effects of the present invention are: on the one hand, it avoids the problem of the bottom protrusion directly below the reducer conflicting with the installation space; on the other hand, it can ensure low noise requirements: 1. The overall structural rigidity of the upper box is good, the processing technology is good, the coaxiality accuracy of the paired bearings is high, the transmission of the first-stage gear shaft assembly has the greatest impact on noise, and the multi-stage transmission is arranged in the upper box, which helps to reduce noise; 2. The shaft of the first-stage gear shaft assembly is directly designed into the multi-stage speed change assembly, and is splined to the output shaft of the external power source. Compared with the direct-plug structure of the output shaft, it eliminates the noise impact of the external output shaft on the first-stage gear shaft assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic diagram of a three-dimensional modeling structure in one embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the cross-sectional structure along the axial direction of the multi-stage speed change assembly in one embodiment of the present utility model.

[0019] Figure 3 for Figure 1 Right side view of the embodiment shown in .

[0020] Figure 4 This is a structural schematic diagram of a differential assembly in an embodiment of the present utility model. DETAILED DESCRIPTION

[0021] The following further describes specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the descriptions of these embodiments are intended to aid understanding of the present invention and do not constitute limitations on the present invention. Furthermore, the technical features involved in the various embodiments of the present invention described below may be combined with one another as long as they do not conflict with one another.

[0022] like Figures 1 to 4 As shown, a transmission comprises a multi-speed transmission assembly and a differential assembly, as well as an upper case 1 and a lower case 2 connected thereto. Figure 1 As shown, the upper housing 1 and the lower housing 2 are joined to form a closed outer shell, within which the multi-speed transmission assembly and the differential assembly are assembled. To facilitate the structural description of this case, the end of the multi-speed transmission assembly's output shaft connected to an external power source (such as a motor) is defined as the upper end, and the end opposite the upper end (usually also farther from the external power source) is defined as the lower end. The straight line between the upper and lower ends is perpendicular to the gear shaft of the multi-speed transmission assembly. The axial direction of the gear shaft of the multi-speed transmission assembly toward the external power source is defined as right, and the direction opposite to right is defined as left.

[0023] The multi-speed transmission assembly is arranged in the upper case 1, the upper half of the differential assembly is arranged in the lower part of the upper case 1, and the lower half of the differential assembly is arranged in the lower case 2. Semicircular holes are opened on the left and right sides of the connecting ends of the upper case 1 and the lower case 2 to form a mounting shaft hole for the left and right half-shafts to pass through. The final gear of the multi-speed transmission assembly is engaged with the driven gear 21 of the differential assembly to achieve drive. Taking the plane where the cross shaft 22 of the differential assembly is located as the reference plane, the plane where the driven gear 21 is located is parallel to but offset from the reference plane, and the outer shell of the differential assembly is also offset from the reference plane and the offset direction is the same as that of the driven gear 21. Due to the offset setting, the shape of the bottom shell of the lower case 2 that accommodates the differential assembly can be designed to converge inward. Figure 2 In one embodiment, the bottom housing shape is omitted; the omitted portion is a freely designed feature that avoids the problem of a protruding bottom directly below the lower housing 2 conflicting with the installation space. Furthermore, the upper housing 1 is a monolithic structure, which reduces housing gaps and abnormal noise, and provides high structural strength. The multi-speed transmission assembly is housed within the upper housing 1, eliminating the need for excessive left-right alignment during assembly. As long as the corresponding mounting position of the multi-speed transmission assembly on the upper housing 1 is machined accurately and the multi-speed transmission assembly is properly installed, assembly accuracy is guaranteed.

[0024] The differential assembly in this case is relatively easy to install. The outer housing of the differential assembly comprises a connected left housing 201 and a right housing 202. The connecting surface of the left housing 201 and the right housing 202 coincides with the reference plane. The left and right half-shafts of the differential assembly are placed in the mounting holes. This means that the left and right axial directions of the differential assembly require no additional adjustment and are automatically locked in place by the left and right semi-circular holes of the lower housing 2. For example, with a rightward offset, the driven gear 21 and the right housing 202 are both positioned to the right of the reference plane. The half-shaft gear 203 of the differential assembly located to the right of the reference plane is connected to the output shaft. The left and right housings 201 and 202 are connected between the upper housing 1 and the lower housing 2 via bearings.

[0025] To adjust the center of gravity of the entire differential assembly, the differential assembly also includes a counterweight 204 positioned to the side offset from the driven gear 21. For example, if the left housing 201 is longer and the center of gravity needs to be shifted to the right, a counterweight can be placed on the right side to shift the center of gravity to the right. This adjusts the center of gravity of the entire transmission and ensures balanced force and stability at all installation locations. To reduce unnecessary installation steps, the counterweight 204 is integral with the driven gear 21. The counterweight 204 utilizes a stepped mounting structure for connection to the outer housing of the differential assembly, serving not only as a counterweight but also as a limiter.

[0026] The multi-stage transmission assembly in this case does not exclude the situation where there are only two-stage gear shifting. However, usually after the two-stage gear transmission is integrated as a whole, the external dimensions are relatively small, which generally does not conflict with the spatial layout of the installation location. Therefore, the multi-stage transmission assembly mostly refers to a three-stage or more gear transmission structure. Despite this, the interpretation of the multi-stage transmission assembly should not exclude the two-stage gear structure.

[0027] Taking the three-stage gear structure as an example, an applicable embodiment scenario of this case is described. Figure 2 As shown, when the multi-stage speed change assembly is a three-stage reducer, the multi-stage speed change assembly includes, from top to bottom, a primary gear shaft assembly 11, a secondary gear shaft assembly 12, and a tertiary gear shaft assembly 13. The primary gear shaft assembly 11 is connected to the output shaft of the external power source through a spline, and the primary gear shaft assembly 11 and the secondary gear shaft assembly 12, the secondary gear shaft assembly 12 and the tertiary gear shaft assembly 13 are driven by gear meshing. The gear installed on the tertiary gear shaft assembly 13 is a low-speed gear that meshes with the driven gear 21 to drive the driven gear 21 to rotate. The axes of the primary gear shaft assembly 11, the secondary gear shaft assembly 12, the tertiary gear shaft assembly 13 and the driven gear 21 are all on the same plane, as shown in FIG. Figure 3 Multi-speed transmission can be achieved by switching the gear shift mechanism. The gear shift mechanism is not the key point of protection in this case and will not be described in detail.

[0028] The first-stage gear shaft assembly 11, the second-stage gear shaft assembly 12, the third-stage gear shaft assembly 13 and the shaft of the driven gear 21 are all on the same plane, which can ensure the stability of the gear transmission and reduce noise, and it is easier to ensure the processing accuracy of the installation position of each gear shaft of the upper box 1. The three gear shafts are installed on the same plane, which is easy to achieve during installation. For example, the same assembly structure is used to slide each gear shaft to the preset position in turn, as can be seen in the subsequent instructions.

[0029] In the preferred matching tooth shape, the gears of the three-stage reducer and the driven gear 21 are both helical gears or cylindrical gears.

[0030] The outer housing serves as the foundation of the transmission mechanism. Besides possessing sufficient strength and rigidity, it must also be easy to install and secure. Therefore, the upper housing 1 is equipped with a mounting platform 14 facing the lower housing 2 and a mounting cover 15 facing the external power source. The mounting platform 14 is provided with mounting holes for bolt connections. The mounting cover 15 is formed on the same side as the driven gear 21 and extends from the edge of the upper housing 1 where the primary and secondary gear shaft assemblies 11 and 12 are located. The mounting platform 14, mounting cover 15, and upper housing 1 form a monolithic, integrated structure.

[0031] The assembly sequence for the three-stage gear structure is as follows:

[0032] 1. First, assemble the right bearing of the first-stage gear shaft assembly 11. Insert the first-stage gear shaft assembly 11 through the left shaft hole and install it on its right bearing. Then assemble the left bearing, retaining spring and blind cover of the first-stage gear shaft assembly 11.

[0033] 2. Install the secondary gear shaft assembly 12 from the right side. Figure 2 (As shown, the direction toward the reader is the rear direction in the drawing) so that the front side of the first gear shaft assembly 11 is close to the front inner wall of the upper housing 1, and the left bearing, retaining spring and blind cover of the second gear shaft assembly 12 are installed. The second gear shaft assembly 12 continues to move to the left and is installed in its left bearing, and then the right bearing, retaining spring and blind cover are installed;

[0034] 3. Install the three-stage gear shaft assembly 13 from the shaft hole on the right side of the upper box body 1. The three-stage gear shaft assembly 13 leans forward so that the front side of the three-stage gear shaft assembly 13 is close to the front inner wall of the upper box body 1, and install its left side bearing, retaining ring and blind cover. The three-stage gear shaft assembly 13 continues to move to the left and install it into its left side bearing, and then install its right side bearing, retaining ring and blind cover.

[0035] The above assembly sequence is to assemble each stage gear shaft assembly separately. Since the first-stage gear shaft assembly 11, the second-stage gear shaft assembly 12, the third-stage gear shaft assembly 13 and the axis of the driven gear 21 are all on the same plane, the same assembly tool can be used for positioning during assembly, which can improve assembly accuracy and reduce assembly difficulty.

[0036] Of course, for efficient and rapid assembly, a synchronous assembly method can also be adopted: the first-stage gear shaft assembly 11 remains the same as the above-mentioned assembly embodiment, and the second-stage gear shaft assembly 12 and the third-stage gear shaft assembly 13 are assembled synchronously, which will not be repeated here.

[0037] This patented solution can ensure low noise requirements: 1. The overall structural rigidity of the upper housing 1 is good, the processing technology is good, the coaxiality accuracy of the paired bearings is high, the transmission of the first-stage gear shaft assembly 11 has the greatest impact on noise, and the multi-stage transmission is arranged in the upper housing 1, which helps to reduce noise; 2. The shaft of the first-stage gear shaft assembly 11 is directly designed into the multi-stage speed change assembly, and is spline-connected to the output shaft of the external power source (such as the motor shaft). Compared with the direct-plug structure of the output shaft, it eliminates the noise impact of the external output shaft on the first-stage gear shaft assembly 11.

[0038] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term and should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0039] It should be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or system. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the product or system comprising the element.

[0040] The foregoing description shows and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the inventive concept described herein by the teachings above or by techniques or knowledge in the relevant art. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be within the scope of the appended claims.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A transmission, characterized in that: The invention comprises a multi-speed transmission assembly and a differential assembly, and an upper housing (1) and a lower housing (2) connected thereto. The multi-speed transmission assembly is arranged in the upper housing (1), the upper half of the differential assembly is arranged in the lower part of the upper housing (1), and the lower half of the differential assembly is arranged in the lower housing (2). The final gear of the multi-speed transmission assembly is meshed with the driven gear (21) of the differential assembly to realize driving. The plane where the cross shaft (22) of the differential assembly is located is used as a reference plane. The plane where the driven gear (21) is located is parallel to but offset from the reference plane. The outer housing of the differential assembly is also offset from the reference plane and the offset direction is the same as that of the driven gear (21).

2. A transmission according to claim 1, characterized in that: The outer housing of the differential assembly comprises a left housing (201) and a right housing (202) connected to each other, and the connection surface between the left housing (201) and the right housing (202) coincides with the reference surface.

3. A transmission according to claim 2, characterized in that: The driven gear (21) and the right housing (202) are both arranged on the right side of the reference plane; the half-shaft gear (203) located on the right side of the reference plane in the differential assembly is connected to the output shaft; the left housing (201) and the right housing (202) are respectively installed between the upper housing (1) and the lower housing (2) through bearings.

4. The transmission according to claim 1, characterized in that: The differential assembly further includes a counterweight (204) arranged on an offset side of the driven gear (21).

5. A transmission according to claim 4, characterized in that: The counterweight (204) and the driven gear (21) are an integrated structure, and the counterweight (204) adopts a mounting step structure for connecting to the outer housing of the differential assembly.

6. A transmission according to any one of claims 1 to 5, characterized in that: When the multi-stage speed change assembly is a three-stage speed reducer, the multi-stage speed change assembly comprises, from top to bottom, a first-stage gear shaft assembly (11), a second-stage gear shaft assembly (12), and a third-stage gear shaft assembly (13); the first-stage gear shaft assembly (11) is connected to the output shaft of the external power source via a spline; the first-stage gear shaft assembly (11) and the second-stage gear shaft assembly (12), the second-stage gear shaft assembly (12) and the third-stage gear shaft assembly (13) are driven by gear meshing; the gear installed on the third-stage gear shaft assembly (13) is a low-speed gear meshing with the driven gear (21) to drive the driven gear (21) to rotate; the axes of the first-stage gear shaft assembly (11), the second-stage gear shaft assembly (12), the third-stage gear shaft assembly (13), and the driven gear (21) are all on the same plane.

7. A transmission according to claim 6, characterized in that: The gears of the three-stage speed reducer and the driven gear (21) are both helical gears or cylindrical gears.

8. The transmission according to claim 6, characterized in that: The upper box body (1) is provided with a mounting platform (14) facing the lower box body (2) and a mounting cover (15) facing the external power source. The mounting cover (15) is formed by extending from the edge of the upper box body (1) where the first-stage gear shaft assembly (11) and the second-stage gear shaft assembly (12) are located. The mounting platform (14), the mounting cover (15) and the upper box body (1) are an integral one-piece structure.

9. A transmission according to claim 8, characterized in that: The mounting cover (15) is on the same side as the driven gear (21).

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