Speed-change device and traveling vehicle

Abstract

Provided are: a speed-change device that has a simple configuration, is capable of suppressing a manufacturing cost and achieving miniaturization and weight reduction and has a high layout flexibility; and a traveling vehicle.　In a speed-change device (100), rotation is transmitted at a plurality of speed ratios between a first shaft (101) and a second shaft (102) which have substantially parallel rotation shafts. The first shaft (101) has a first rotating body (110), a second rotating body (120), and a switching rotating body (150) which are coaxially rotatable. The second shaft (102) has a third rotating body (130) and a fourth rotating body (140). Rotation is transmitted to the first rotating body (110) and the third rotating body (130) via a first transmission member (111). Rotation is transmitted to the second rotating body (120) and the fourth rotating body (140) via a second transmission member (121). The switching rotating body (150) is configured to be able to switch between a first transmission state in which power is transmitted from the switching rotating body (150) to the first rotating body (110) and a second transmission state in which power is transmitted from the switching rotating body (150) to the second rotating body (120).

Description

Transmission and a traveling vehicle

[0001] The present invention relates to a transmission having a first shaft and a second shaft with substantially parallel rotation axes, and transmitting rotation at a plurality of gear ratios between the first shaft and the second shaft, and a traveling vehicle equipped with the transmission.

[0002] Conventionally, a transmission having a first shaft and a second shaft with substantially parallel rotation axes, and transmitting rotation at a plurality of gear ratios between the first shaft and the second shaft, and a traveling vehicle equipped with the transmission are known (see, for example, Patent Document 1). An automatic transmission A (the names and symbols of the components in this paragraph follow the notation of Patent Document 1) known in Patent Document 1 and an automobile equipped with the automatic transmission A have an auxiliary transmission 3 that transmits power from a torque converter 2 connected to an engine output shaft 1 to a main transmission 4. The auxiliary transmission 3 has a chain drive mechanism 32 that transmits power from an input shaft 31 to an input shaft 41 via a clutch 34, a chain drive mechanism 32 that transmits power from the input shaft 31 to the input shaft 41 via a clutch 36, and a chain drive mechanism 33 with different gear ratios, and is configured to be shiftable by selectively connecting the clutch 34 and the clutch 36.

[0003] Japanese Patent Laid-Open No. 63-083449

[0004] The automatic transmission A (the names and symbols of the components in this paragraph follow the notation of Patent Document 1) known in Patent Document 1 and the like is configured to switch power transmission by two sets of clutches 34 and 36 for two sets of chain drive mechanisms 32 and 33. Therefore, an increase in the number of parts may cause the automatic transmission A to become larger, and there is a risk that the manufacturing cost and weight will increase. In addition, it is necessary to arrange two sets of clutches 34 and 36 and drive sprockets 32a and 33a of two sets of chain drive mechanisms 32 and 33 on the input shaft 31, and there is a risk that the layout freedom of the automatic transmission A will decrease.

[0005] In particular, when used in electric vehicles that use electric motors as a power source, electric motors can generate greater torque than internal combustion engines even at low rotational speeds, so a multi-speed transmission is not an essential component. Furthermore, due to the high cost of batteries that supply power to the motor, transmissions are very often not installed at all. In addition, in small electric vehicles, vehicle costs and layout space are limited, making it difficult to install large, expensive transmissions. Also, due to limitations on motor output imposed by standards, it is difficult to increase motor output. In such cases, the absence of a transmission may result in the inability to properly transmit power from the motor according to driving conditions, potentially leading to adverse effects on driving performance, such as insufficient climbing ability making it impossible to climb hills. Moreover, the transmissions used in automobiles powered by internal combustion engines may be excessive in terms of performance, cost, and size.

[0006] The present invention aims to solve these problems and to provide a transmission and vehicle that have a simple configuration, can reduce manufacturing costs, can be miniaturized and lightweight, and offer a high degree of layout flexibility.

[0007] The present invention provides a transmission device having a first shaft and a second shaft having substantially parallel rotating shafts, and transmitting rotation between the first shaft and the second shaft at a plurality of gear ratios, wherein the first shaft has a first rotating body and a second rotating body that are rotatable coaxially, and a switching rotating body provided between the first rotating body and the second rotating body and rotating together with the first shaft, the second shaft has a third rotating body that rotates in conjunction with the first rotating body and a fourth rotating body that rotates in conjunction with the second rotating body, the rotation of the first rotating body and the third rotating body is transmitted via a first transmission strip, the rotation of the second rotating body and the fourth rotating body is transmitted via a second transmission strip, and the switching rotating body is configured to be switchable between a first transmission state in which power is transmitted from the switching rotating body to the first rotating body and a second transmission state in which power is transmitted from the switching rotating body to the second rotating body, thereby solving the aforementioned problems. Furthermore, the present invention provides a vehicle that is equipped with the above-described transmission device, thereby solving the aforementioned problems.

[0008] According to the inventions of claims 1 and 4, the first shaft has a first rotating body and a second rotating body that are rotatable coaxially, and a switching rotating body provided between the first rotating body and the second rotating body that rotates together with the first shaft. As a result, the speed change operation can be performed with only one switching rotating body, reducing the number of parts and lowering manufacturing costs. Furthermore, because the switching rotating body is provided between the first rotating body and the second rotating body, the switching rotating body and the first rotating body, and the switching rotating body and the second rotating body can each be used as members of a friction clutch, eliminating the need to provide a separate clutch mechanism. This reduces the overall width in the direction of the rotation axis, enabling miniaturization, weight reduction, and improved layout flexibility. Furthermore, since the rotation is transmitted between the first and third rotating bodies via the first transmission strip, and between the second and fourth rotating bodies via the second transmission strip, the distance between the first and second axes can be freely set, improving layout flexibility. In addition, even if there are manufacturing errors in the distance or parallelism of the first and second axes, or if there are axial displacements or tilts when the first and second rotating bodies receive axial forces as members of a friction clutch, rotation can be transmitted without problems, thereby reducing manufacturing costs. Moreover, since the switching rotating body is configured to be switchable between a first transmission state in which power is transmitted from the switching rotating body to the first rotating body, and a second transmission state in which power is transmitted from the switching rotating body to the second rotating body, even when the drive source of the vehicle is an electric motor and there are limitations on motor output, the driving performance can be improved by, for example, setting the first transmission state to a low-speed gear for acceleration and the second transmission state to a high-speed gear for reducing power consumption.

[0009] According to the configuration described in claim 2, the switching rotating body is movable in the axial direction of the first shaft, and when the switching rotating body moves toward the first rotating body, a first transmission state is realized when one axial side surface of the switching rotating body comes into contact with the axial side surface of the first rotating body toward the switching rotating body, and when the switching rotating body moves toward the second rotating body, a second transmission state is realized when the other axial side surface of the switching rotating body comes into contact with the axial side surface of the second rotating body toward the switching rotating body, thereby enabling the first and second transmission states to be switched by axial movement of the switching rotating body alone, eliminating the need to add a separate clutch member, and further miniaturization and weight reduction can be achieved.

[0010] According to the configuration described in claim 3, the first transmission strip is composed of a chain wrapped around the first rotating body and the third rotating body, and the second transmission strip is composed of a chain wrapped around the second rotating body and the fourth rotating body, thereby enabling reliable transmission of power input to the first shaft to the second shaft.

[0011] A schematic diagram of a vehicle according to one embodiment of the present invention. A schematic diagram of the neutral position of a transmission according to one embodiment of the present invention. A schematic diagram of the first transmission state of a transmission according to one embodiment of the present invention. A schematic diagram of the second transmission state of a transmission according to one embodiment of the present invention.

[0012] The transmission and vehicle of the present invention will be described below with reference to the drawings. A vehicle 200 according to one embodiment of the present invention has, as schematically shown in Figure 1, two driven wheels 203 at the front in the direction of travel (in the direction of the white arrows shown by solid lines in Figure 1) and two drive wheels 202 at the rear in the direction of travel. The two drive wheels 202 are driven by the rotation of the output shaft of a drive device 201 such as an electric motor or engine, which is transmitted to the drive wheel shaft 204 via the transmission 100 and differential 205, thereby driving the vehicle 200 forward or backward. Further power transmission paths may be added after the transmission 100 so that all four wheels are drive wheels 202, and furthermore, any number of drive wheels and driven wheels in the vehicle as a whole is acceptable as long as at least one drive wheel is driven via the transmission 100.

[0013] A transmission 100 according to one embodiment of the present invention has, as schematically shown in Figure 2, a first shaft 101 to which the rotation of the output shaft of the drive unit 201 is transmitted, and a second shaft 102 to which the rotation is transmitted to the drive wheel 202. The first shaft 101 has a first sprocket 110, which is a first rotating body, and a second sprocket 120, which is a second rotating body, which are coaxial and rotatable independently of the first shaft 101, and a switching rotating body 150 provided between the first sprocket 110 and the second sprocket 120, which rotates integrally with the first shaft 101 and is movable in the axial direction.

[0014] The second shaft 102 has a third sprocket 130, which is a third rotating body, and a fourth sprocket 140, which is a fourth rotating body, both of which rotate together. The third sprocket 130 rotates in conjunction with the first sprocket 110 via a first chain 111, which is a first transmission link, and the fourth sprocket 140 rotates in conjunction with the second sprocket 120 via a second chain 121, which is a second transmission link. The tooth ratio of the first sprocket 110 and the third sprocket 130 is set to be different from the tooth ratio of the second sprocket 120 and the fourth sprocket 140. By adjusting the number of teeth of the first sprocket 110 and the third sprocket 130, and the number of teeth of the second sprocket 120 and the fourth sprocket 140, the gear ratio can be freely set to match the driving performance of the vehicle 200.

[0015] The switching rotating body 150 is configured to be movable in the axial direction of the first shaft 101 and to be fixed in its axial position by an operating means (not shown). A first clutch surface 151 is formed on the axial side of the switching rotating body 150 on the first sprocket 110 side, and a second clutch surface 152 is formed on the axial side of the switching rotating body 120 side. A first clutch receiving surface 112 is formed on the axial side of the first sprocket 110 on the switching rotating body 150 side, and a second clutch receiving surface 122 is formed on the axial side of the second sprocket 120 on the switching rotating body 150 side.

[0016] As shown in Figure 2, when the switching rotating body 150 is in a neutral position relative to the first sprocket 110 and the second sprocket 120, and the first clutch surface 151 and the first clutch receiving surface 112, and the second clutch surface 152 and the second clutch receiving surface 122 are not in contact, both the first sprocket 110 and the second sprocket 120 are configured to rotate independently of the first shaft 101, and therefore no rotation is transmitted between the first shaft 101 and the second shaft 102.

[0017] As shown in Figure 3, the switching rotating body 150 is moved toward the first sprocket 110 by the operating means, and the first clutch surface 151 is pressed against the first clutch receiving surface 112, resulting in a first transmission state in which rotation is transmitted from the first shaft 101 - switching rotating body 150 - first sprocket 110 - first chain 111 - third sprocket 130 - second shaft 102 (in the order of the arrows shown by solid lines in Figure 3). At this time, the rotational speeds of the first shaft 101 and the second shaft 102 are determined by the tooth ratio of the first sprocket 110 and the third sprocket 130. Here, the rotational speeds of the first shaft 101 and the second shaft 102 can be freely set by changing the number of teeth of the first sprocket 110 and the third sprocket 130 to adjust the tooth ratio.

[0018] As shown in Figure 4, the switching rotating body 150 is moved towards the second sprocket 120 by the operating means, and the second clutch surface 152 is pressed against the second clutch receiving surface 122, resulting in a second transmission state in which rotation is transmitted from the first shaft 101 - switching rotating body 150 - second sprocket 120 - second chain 121 - fourth sprocket 140 - second shaft 102 (in the order of the arrows shown by solid lines in Figure 4). At this time, the rotational speeds of the first shaft 101 and the second shaft 102 are determined by the tooth ratio of the second sprocket 120 and the fourth sprocket 140. Here, the rotational speeds of the first shaft 101 and the second shaft 102 can be freely set by changing the number of teeth of the second sprocket 120 and the fourth sprocket 140 to adjust the tooth ratio.

[0019] The gear ratio of the first sprocket 110 and the third sprocket 130 is set to be different from the gear ratio of the second sprocket 120 and the fourth sprocket 140, so that the gear can be changed by switching between the first and second transmission states. The gear shift device 100 has only one switching rotating body 150 and is configured to allow gear changes by switching between the first and second transmission states only by moving it in the axial direction of the first shaft 101 using an operating means, so that it can be made smaller and lighter, and the time required for gear changes can also be shortened. In addition, in the gear shift device 100, the surface properties of the first clutch surface 151 and the first clutch receiving surface 112 and the second clutch surface 152 and the second clutch receiving surface 122, as well as the pressing force of the switching rotating body 150 can be appropriately set according to the required performance, etc. For example, if excessive external force is input to the transmission 100 from the drive unit 201 or drive wheels 202, the surface properties and pressing force can be set so that the first clutch surface 151 and the first clutch receiving surface 112 or the second clutch surface 152 and the second clutch receiving surface 122 slide against each other, thereby preventing damage to each component while power transmission is performed.

[0020] Although one embodiment of the present invention has been described above, the present invention is not limited to the above configuration. In this embodiment, the rotation of the output shaft of the drive device 201 is transmitted to the first shaft 101 in the traveling vehicle 200, and the rotation is transmitted from the second shaft 102 to the drive wheel 202, but the connection may be reversed, and it may also be used for purposes other than traveling vehicles. In addition, the distance in the rotational axis direction between the first clutch receiving surface 112 of the first sprocket 110 and the second clutch receiving surface 122 of the second sprocket 120 is greatly exaggerated in the illustration, but this distance should be greater than the width between the first clutch surface 151 and the second clutch surface 152 of the switching rotating body 150, and should be such that both the first clutch surface 151 and the first clutch receiving surface 112, and the second clutch surface 152 and the second clutch receiving surface 122 do not come into contact at the same time.

[0021] Furthermore, the first clutch receiving surface 112 of the first sprocket 110, the second clutch receiving surface 122 of the second sprocket 120, and the first clutch surface 151 and second clutch surface 152 of the switching rotating body 150 may be the surfaces of friction members provided on the sides of the first sprocket 110, the second sprocket 120, and the switching rotating body 150, and either of the contacting surfaces may be the surface of the material of the first sprocket 110, the second sprocket 120, and the switching rotating body 150 itself.

[0022] Furthermore, the first sprocket 110 and the second sprocket 120 may be allowed to move toward the switching rotating body 150 if the axial movement of the first shaft 101 is restricted when the switching rotating body 150 is pressed against them. Also, the third sprocket 130 and the fourth sprocket 140 may be allowed to move toward the axial direction of the second shaft 102 to the extent that they follow the movement of the first sprocket 110 and the second sprocket 120. Moreover, the switching rotating body 150 may rotate integrally with the first shaft 101 and be fixed in the axial direction, and the first sprocket 110 and the second sprocket 120 may be configured to be switchable between a first transmission state, a neutral state, and a second transmission state by moving toward the axial direction.

[0023] In this embodiment, the first, second, third, and fourth rotating bodies are sprockets, and the first and second transmission strips are chains, but a combination of pulleys and a belt may also be used. Guide members for guiding the first and second transmission strips, and tensioner members for adding tension may also be provided. In this embodiment, the first and second transmission states can be switched using the switching rotating body 150, but by having multiple similar configurations, it may be possible to configure the system to switch between three or more transmission states. Furthermore, by arranging multiple sets of sprockets and switching rotating bodies that rotate in conjunction via a chain or belt alternately, it may be possible to configure the system to switch between three or more transmission states.

[0024] 100... Transmission 101... First shaft 102... Second shaft 110... First sprocket (first rotating body) 111... First chain (first transmission string) 112... First clutch receiving surface (axial side) 120... Second sprocket (second rotating body) 121... First chain (second transmission string) 122... Second clutch receiving surface (axial side) 130... Third sprocket (third rotating body) 140... Fourth sprocket (fourth rotating body) 150... Switching rotating body 151... First clutch surface (axial side) 152... Second clutch surface (axial side) 200... Vehicle 201... Drive unit 202... Drive wheel 203... Driven wheel 204... Drive wheel shaft 205... Differential

Claims

1. A transmission having a first shaft and a second shaft having substantially parallel rotating axes, and transmitting rotation between the first shaft and the second shaft at a plurality of gear ratios, wherein the first shaft has a first rotating body and a second rotating body that are rotatable coaxially, and a switching rotating body provided between the first rotating body and the second rotating body and rotating together with the first shaft, the second shaft has a third rotating body that rotates in conjunction with the first rotating body, and a fourth rotating body that rotates in conjunction with the second rotating body, the rotation of the first rotating body and the third rotating body is transmitted via a first transmission strip, the rotation of the second rotating body and the fourth rotating body is transmitted via a second transmission strip, and the switching rotating body is configured to be switchable between a first transmission state in which power is transmitted from the switching rotating body to the first rotating body, and a second transmission state in which power is transmitted from the switching rotating body to the second rotating body.

2. The transmission according to claim 1, characterized in that the switching rotating body is movable in the axial direction of the first shaft, and the first transmission state is realized when the switching rotating body moves toward the first rotating body and one axial side surface of the switching rotating body comes into contact with the axial side surface of the first rotating body toward the switching rotating body, and the second transmission state is realized when the switching rotating body moves toward the second rotating body and the other axial side surface of the switching rotating body comes into contact with the axial side surface of the second rotating body toward the switching rotating body.

3. The transmission according to claim 1, characterized in that the first transmission strip is composed of a chain wrapped around the first rotating body and the third rotating body, and the second transmission strip is composed of a chain wrapped around the second rotating body and the fourth rotating body.

4. A vehicle equipped with a transmission in the power transmission path from a drive source to the drive wheels, wherein the transmission is configured as the transmission described in any one of claims 1 to 3.

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