Drive force transmission device

Abstract

According to the oil supply section (7) of the transmission device (1), the coil springs (9a, 9b) apply force to the oil supply body (8) in the following third direction. That is, when the rotational axis of the pinion (2) is taken as the first direction, and the direction of a specific tangent in the tangent line of the circle drawn when the outermost circumference of the needle roller (4) revolves is taken as the second direction, the third direction is a direction perpendicular to both the first and second directions. As a result, the decrease in the oil supply capacity to the needle roller (4) due to wear of the oil supply body (8) can be suppressed.

Description

Technical Field

[0001] This disclosure relates to a driving force transmission device. Background Technology

[0002] In the past, for example, such as Figure 20 As shown, in the pinion 101 of the rack and pinion drive force transmission device 100, a so-called needle roller type is sometimes used for the purpose of preventing backlash, etc. (for example, see Patent Document 1). Here, the needle roller type pinion 101 includes, for example, a plurality of needle rollers 102 as described below and two support bodies 103 that support these needle rollers 102.

[0003] That is, the needle roller 102 is, for example, a metal cylinder, and two support bodies 103 support multiple needle rollers 102 at both ends in the axial direction, so that the multiple needle rollers 102 are arranged in a cylindrical shape parallel to the rotational axis of the pinion 101. Furthermore, in the drive force transmission device 100, while each needle roller 102 meshes with other gears as tooth tips, it drives the pinion 101 to rotate, for example.

[0004] However, in the drive force transmission device 100 using the aforementioned needle roller type pinion 101, oil needs to be supplied to the surface of the gears in order for the needle roller 102 to mesh smoothly with other gears. Therefore, to avoid the inconvenience of manually applying oil directly to the gears, a structure is disclosed in which an oil supply unit 104 is installed on the pinion 101 and supplies oil to the needle roller 102.

[0005] That is, the oil supply unit 104 has an oil supply body 105 and a force application unit 106. Here, the oil supply body 105 is the source of oil supplied to the needle roller 102, for example, an oleopolymer. Furthermore, the oil supply body 105 has a cylindrical surface 107, which has a radius substantially the same as the radius of revolution of the outermost circumference of the needle roller 102 when the pinion 101 rotates. Furthermore, the force application unit 106 applies force to the oil supply body 105 so that the cylindrical surface 107 contacts the outermost circumference of the needle roller 102.

[0006] Furthermore, the oil supply section 104 slides on the cylindrical surface 107 via the outermost periphery of the needle roller 102, accompanying the rotation of the pinion 101, thereby supplying oil from the oil supply body 105 to the needle roller 102. In this manner, oil is supplied to the needle roller 102 in the drive force transmission device 100, ensuring smooth engagement.

[0007] In addition, according to the driving force transmission device 100, the oil supply body 105 is arranged in an arc shape. The coil springs 106a and 106b constituting the force application unit 106 apply force to the oil supply body 105 in a direction that is perpendicular to the tangent of the arc at each part and perpendicular to the rotation axis of the pinion 101 at each part, thereby pressing the cylindrical surface 107 against the needle roller 102.

[0008] Furthermore, in the drive force transmission device 100, the two ends of the oil supply body 105 are hooked by the hooks 108 to hold the oil supply body 105 as a whole. Moreover, the oil supply capacity to the pinion 101 is determined based on the pressing force on the needle roller 102, which is approximately the sum of the pressing force on the needle roller 102, the force applied by the force application unit 106, and the elastic force accompanying the elastic deformation of the oil supply body 105.

[0009] However, in this manner, when the cylindrical surface 107 wears and retracts, the elastic coefficient of the oil supply body 105 changes significantly. Consequently, the pressing pressure also changes significantly, and the oil supply capacity to the pinion 101 decreases substantially. Existing technical documents Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2013-19435 Summary of the Invention The technical problem that the invention aims to solve

[0011] The technical problem of this disclosure is to suppress the decrease in the oil supply capacity to the needle rollers due to wear of the oil supply body in a drive force transmission device that includes a needle roller type pinion and supplies oil to the needle rollers from an oil supply body so that the needle roller type pinion smoothly meshes with other gears. Technical solutions adopted to solve technical problems

[0012] According to a first embodiment of this disclosure, the driving force transmission device includes a pinion that meshes with other gears and an oil supply section that supplies oil to the pinion. Furthermore, in the pinion, a plurality of cylindrical needle rollers are arranged parallel to the axis of rotation of the pinion and in a cylindrical shape, with each needle roller serving as a tooth tip that meshes with other gears.

[0013] Furthermore, the oil supply unit includes an oil supply body and a force application unit. The oil supply body, which is the source of oil supplied to the needle rollers, has a cylindrical surface with a radius substantially the same as the radius of revolution of the outermost circumference of the needle rollers when the pinion rotates. The force application unit applies force to the oil supply body to bring the cylindrical surface into contact with the outermost circumference of the needle rollers. In the oil supply unit, the outermost circumference of the needle rollers slides on the cylindrical surface as the pinion rotates, thereby supplying oil from the oil supply body to the needle rollers.

[0014] Furthermore, when the axis of rotation of the pinion is referred to as the first direction, and the direction of a specific tangent in the circle traced by the outermost periphery of the needle roller during its revolution is referred to as the second direction, the force-applying unit applies force to the oil supply body at at least two locations along a third direction perpendicular to both the first and second directions. Furthermore, according to the second embodiment of the drive force transmission device of this disclosure, the oil supply body, through its own elasticity, brings its cylindrical surface into contact with the outermost periphery of the needle roller. Thus, the drive force transmission device of this disclosure, in a drive force transmission device that includes a needle roller-type pinion and supplies oil to the needle roller from the oil supply body to ensure smooth meshing of the needle roller-type pinion with other gears, potentially suppresses the decrease in oil supply capacity to the needle roller due to wear of the oil supply body. Attached Figure Description

[0015] Figure 1 This is a front view showing the interior of the driving force transmission device (Example 1). Figure 2 This is a perspective view of the driving force transmission device (Example 1). Figure 3 This is a three-dimensional view showing the interior of the driving force transmission device (Example 1). Figure 4 This is an exploded perspective view of the oil supply unit (Example 1). Figure 5 This is a top view of the oil supply body (Example 1). Figure 6 This is a front view of the oil supply body (Example 1). Figure 7 This is a top view of the casing (Example 1). Figure 8 This is the front view of the casing (Example 1). Figure 9 This is an explanatory diagram showing the state of the oil supply section before wear (Example 1). Figure 10 This is an explanatory diagram showing the state of the oil supply section after wear (Example 1). Figure 11 This is an explanatory diagram showing the state of the adjusted oil supply section (Example 1). Figure 12 This is an exploded perspective view of the oil supply unit (Example 2). Figure 13 This is an explanatory diagram showing the configuration of the oil supply section before wear (Example 2). Figure 14 This is an explanatory diagram showing the configuration of the oil supply section after wear (Example 2). Figure 15 This is an explanatory diagram showing the configuration of the adjusted oil supply section (Example 2). Figure 16This is an explanatory diagram showing the engagement structure of the indicator section on one side and the indicator section on the other side before wear (Example 2). Figure 17 This is an explanatory diagram showing the engagement structure of the indicator section on one side and the indicator section on the other side after wear (Example 2). Figure 18 This is a front view showing the interior of the driving force transmission device (Example 3). Figure 19 This is a three-dimensional view showing the interior of the driving force transmission device (Example 4). Figure 20 This is a front view showing the interior of the drive force transmission device before wear (existing example). Figure 21 This is a front view showing the interior of the drive force transmission device after wear (existing example). Detailed Implementation

[0016] The following examples illustrate in detail the methods for implementing this disclosure. Example

[0017] [Structure of Example 1] Use Figures 1 to 11 The driving force transmission device 1 (hereinafter referred to as transmission device 1) of Embodiment 1 will be described. Transmission device 1 is, for example, as shown in the following description. Figure 1 As shown, this is a gear and rack type consisting of a pinion 2 and a rack 3 meshing together. Furthermore, the transmission device 1 moves various items, for example, by moving the housing (not shown) that houses the pinion 2. Additionally, for example, by driving the pinion 2 to rotate, the pinion 2 moves along the rack 3 while its teeth mesh with the teeth of the rack 3. Moreover, the teeth of the rack 3 have a profile that follows a predetermined cycloidal curve.

[0018] Next, the structure of pinion 2 will be explained (refer to...). Figures 1-3 The pinion 2 is a so-called needle roller type. That is, the pinion 2 includes a plurality of cylindrical metal needle rollers 4 and two support bodies 5A and 5B, which support the plurality of needle rollers 4 at both ends in the axial direction so that the plurality of needle rollers 4 are arranged in a cylindrical shape parallel to the axis of rotation of the pinion 2. In addition, the two support bodies 5A and 5B are, for example, a support body 5A with a cylindrical flange and a support body 5B without a cylindrical flange, respectively. Furthermore, the transmission device 1 drives the pinion 2 to rotate while the individual needle rollers 4 mesh with the teeth of the rack 3 as tooth tips, thereby causing the pinion 2 to travel along the rack 3.

[0019] Here, supports 5A and 5B are each provided with the same number of circular holes as the needle rollers 4 at equal angular intervals. These circular holes accommodate bearings (not shown). Furthermore, supports 5A and 5B are configured such that their respective circular holes face each other, and each needle roller 4 is inserted between supports 5A and 5B. Additionally, portions of the needle rollers 4 on one axial end and the other end are supported by bearings to allow them to rotate within their respective circular holes.

[0020] Furthermore, the transmission device 1 includes an oil supply section 7 to ensure smooth meshing between the needle roller 4 and the teeth of the rack 3. The oil supply section 7 supplies oil to the needle roller 4 and includes an oil supply body 8 and a force application unit 9.

[0021] First, the oil supply body 8 is the source of oil supplied to the needle roller 4, for example, an oil-containing resin. Furthermore, the oil supply body 8 has a cylindrical surface 11, which has a radius substantially the same as the radius of revolution of the outermost circumference of the needle roller 4 when the pinion 2 rotates (see reference). Figure 1 (etc.). In addition, the force application unit 9 applies force to the oil supply body 8 so that the cylindrical surface 11 contacts the outermost periphery of the needle roller 4. Furthermore, when the pinion 2 rotates, the force application unit 9 also supplies oil to the needle roller 4 by pressing the cylindrical surface 11 against the needle roller 4.

[0022] That is, the oil supply section 7 slides on the cylindrical surface 11 via the outermost periphery of the needle roller 4 as the pinion 2 rotates, thereby supplying oil from the oil supply body 8 to the needle roller 4. In addition, the force application unit 9, for example as described later, consists of two coil springs 9a and 9b that serve as force application components.

[0023] In the following description, the axis of rotation of the pinion 2 is sometimes referred to as the first direction D1. Furthermore, the direction of a specific tangent in the circle traced by the outermost circumference of the needle roller 4 during its revolution is sometimes referred to as the second direction D2. Additionally, the direction perpendicular to both the first direction D1 and the second direction D2 is sometimes referred to as the third direction D3. Furthermore, in Embodiment 1, the second direction D2 is aligned with the direction of travel of the pinion 2.

[0024] For example, the force-applying unit 9 applies force to the oil supply body 8 at two locations along the third direction D3 (see reference). Figure 3 , Figure 4 , Figures 9-11 (etc.). More specifically, the force-applying unit 9 has two coil springs 9a and 9b, the bases of which are arranged along the long side on the following flat surface 12.

[0025] That is, the oil supply body 8 has a rectangular flat surface 12 on the side opposite to the cylindrical surface 11 in the third direction D3. The flat surface 12 is parallel to the first direction D1 and the second direction D2, and perpendicular to the third direction D3. Furthermore, the long side direction of the flat surface 12 is approximately aligned with the second direction D2. Additionally, the bases of the coil springs 9a and 9b are arranged along their long sides on the flat surface 12, and the coil springs 9a and 9b are respectively assembled to apply force to the oil supply body 8 from the flat surface 12 along the third direction D3. Furthermore, four side surfaces 13a to 13d (refer to...) are provided between the flat surface 12 and the cylindrical surface 11. Figure 5 , Figure 6 (etc.) slides in contact with the inner peripheral wall of the housing 15, which will be described later.

[0026] Furthermore, the oil supply unit 7 has a retraction unit 16. That is, the retraction unit 16 causes the coil springs 9a and 9b to retract relative to the oil supply body 8 along a third direction D3. More specifically, the retraction unit 16 is, for example, a stop screw (see...). Figures 9-11 (etc.), and screwed into the housing 15 as follows (hereinafter, the advance / retract unit 16 is sometimes referred to as the stop screw 16). Here, the housing 15 is assembled to cover the portion of the flat surface 12 side of the oil supply body 8, and has a top wall portion 17 and four side wall portions 18a to 18d as follows (see Figure 7 , Figure 8 wait).

[0027] That is, the top wall portion 17 is the part for the locking screw 16 to be screwed in, and it faces the flat surface 12. In addition, when the position of the coil springs 9a and 9b is changed by the locking screw 16, the side wall portions 18a to 18d slide in contact with the side surfaces 13a to 13d, respectively. Furthermore, at both ends of the long side of the top wall portion 17, there are fastening allowances 19 for threading the housing 15 to the outer casing.

[0028] Here, the plate 21 that the front end of the locking screw 16 abuts is housed in the space formed by the inner surfaces of the top wall portion 17 and the side wall portions 18a-18d and the flat surface 12 (see reference). Figures 9-11 Plate 21 is rectangular in shape, approximately the same as the flat surface 12. Furthermore, at plate 21, two guide rods 22a and 22b protrude from the side opposite to the surface abutting the locking screw 16 (see reference). Figure 4 , Figures 9-11 (etc.). Guide rods 22a and 22b pass through the inner circumference of coil springs 9a and 9b respectively and abut against the flat surface 12 to guide coil springs 9a and 9b.

[0029] Therefore, the coil springs 9a and 9b are clamped along the third direction D3 between the base provided on the oil supply body 8 side, i.e., on the flat surface 12, and the base provided on the advance / retract unit 16 side, i.e., on the plate 21, and generate an elastic force. Hereinafter, the base provided on the oil supply body 8 side is sometimes referred to as the first base. In addition, the base provided on the advance / retract unit 16 side is sometimes referred to as the second base. Furthermore, the component having the second base is sometimes referred to as the base forming component (in Embodiment 1, the plate 21 is the base forming component).

[0030] Furthermore, by moving the stop screw 16 forward and backward relative to the oil supply body 8 along the third direction D3, the plate 21, i.e., the second base, can move forward and backward along the third direction D3. In addition, the relative positions of the coil springs 9a and 9b relative to the oil supply body 8 in the third direction D3 can be changed along with the movement of the second base in the third direction D3.

[0031] [Adjustment Method in Example 1] Using Figures 9-11 The method for adjusting the oil supply capacity of the transmission device 1 in Embodiment 1 will be described. For example, when the cylindrical surface 11 retracts by a length L toward the flat surface 12 due to wear, etc., and the coil springs 9a and 9b extend by a length L along the third direction D3, the pressing force of the cylindrical surface 11 on the needle roller 4 weakens, and the oil supply capacity to the needle roller 4 decreases (see reference). Figure 9 , Figure 10 wait).

[0032] Therefore, the stop screw 16 is moved to allow the plate 21 to travel a length L (refer to) in the third direction D3 within the housing 15. Figure 11 (etc.). As a result, the second base moves along the third direction D3. As a result, the lengths of the coil springs 9a and 9b are restored to their unused state, and therefore, the pressing force of the cylindrical surface 11 on the needle roller 4 is restored, and the oil supply capacity to the needle roller 4 is also restored.

[0033] [Effects of Embodiment 1] The driving force transmission device 1 of Embodiment 1 includes a needle roller type pinion 2 that meshes with other gears and an oil supply section 7 that supplies oil to the pinion 2. The oil supply section 7 has an oil supply body 8 and coil springs 9a and 9b as force-applying members. First, the oil supply body 8 has a cylindrical surface 11, which has a radius that is substantially the same as the radius of revolution of the outermost circumference of the needle roller 4 when the pinion 2 rotates. Furthermore, the coil springs 9a and 9b apply force to the oil supply body 8 so that the outermost circumference of the needle roller 4 slides on the cylindrical surface 11 as the pinion 2 rotates.

[0034] Furthermore, when the axis of rotation of the pinion 2 is referred to as the first direction D1, and the direction of a specific tangent in the circle traced by the outermost circumference of the needle roller 4 during its revolution is referred to as the second direction D2, the coil springs 9a and 9b apply force to the oil supply body 8 along a third direction D3 that is perpendicular to the first direction D1 and the second direction D2, respectively.

[0035] Therefore, in the transmission device 1, the coil springs 9a and 9b apply force in the same direction. Consequently, the direction of the force exerted by each coil spring 9a and 9b on the cylindrical surface 11 pressing against the needle roller 4 is also the same. That is, the direction of the pressing force of each coil spring 9a and 9b is the same.

[0036] Therefore, even if the cylindrical surface 11 recedes toward the flat surface 12 due to wear, for example, the change in the elastic coefficient of the oil supply body 8 in the pressing direction can be suppressed. As a result, even if the oil supply body 8 wears, the change in elastic force accompanying the change in the elastic coefficient can be suppressed, and thus the change in pressing force accompanying the wear of the cylindrical surface 11 can be suppressed. As a result, the decrease in the oil supply capacity to the needle roller 4 caused by the wear of the oil supply body 8 can be suppressed.

[0037] Furthermore, even if the oil supply capacity decreases due to wear, it can be restored. That is, in the oil supply section 104 of the existing drive force transmission device 100, the positions of the coil springs 106a and 106b differ according to the direction of pressure (see reference). Figure 20 Therefore, when the cylindrical surface 107 of the oil supply body 105 wears and retracts, the bases of the coil springs 106a and 106b respectively provided on the oil supply body 105 will deviate, and the coil springs 106a and 106b themselves will tilt (see reference). Figure 21 Therefore, it is difficult to restore the pressing force of coil springs 106a and 106b, and thus, when the oil supply capacity decreases due to wear, it is difficult to restore the oil supply capacity.

[0038] In contrast, according to the transmission device 1, the coil springs 9a and 9b apply force in the same direction. Therefore, when the cylindrical surface 11 wears and retracts, the pressing force can be adjusted by moving the coil springs 9a and 9b along the direction of force (i.e., the third direction D3). Thus, even if the oil supply capacity decreases due to wear, the oil supply capacity can be restored.

[0039] Furthermore, according to the transmission device 1 of Embodiment 1, the oil supply unit 7 has a forward / reverse unit 16. That is, the stop screw 16, which serves as the forward / reverse unit 16, causes the relative positions of the coil springs 9a and 9b relative to the oil supply body 8 in a third direction D3 to change. Therefore, when the oil supply capacity decreases due to wear, the oil supply capacity can be restored by moving the stop screw 16, which serves as the forward / reverse unit, forward or backward.

[0040] [Structure of Embodiment 2] According to the transmission device 1 of Embodiment 2, the force application unit 9 has three coil springs 9a, 9b, and 9c (refer to...) Figure 12The bases of coil springs 9a, 9b, and 9c are arranged at equal intervals along their long sides on the flat surface 12. Furthermore, each coil spring 9a to 9c has guide rods 22a, 22b, and 22c, but no plate 21 is present within the housing 15. The guide rods 22a, 22b, and 22c extend from the inner surface of the top wall portion 17 along the third direction D3 and enter the inner periphery of the coil springs 9a, 9b, and 9c, guiding the coil springs 9a, 9b, and 9c (see reference). Figures 13-15 (etc.). In addition, the second base is disposed on the housing 15 itself. That is, in embodiment two, the housing 15 itself is a base forming member.

[0041] Furthermore, in the housing 15 of Embodiment 2, the fastening allowance 19 is provided at both ends of the side wall portion 18c, and the threaded hole 19a at the fastening allowance 19 is a longer hole in the third direction D3 (see reference). Figure 12 (etc.). Therefore, by loosening the threaded fastener at the tightening allowance 19, the housing 15 can be moved forward or backward along the third direction D3. By moving the housing 15 forward or backward along the third direction D3, the coil springs 9a, 9b, and 9c can be moved forward or backward relative to the oil supply body 8 along the third direction D3.

[0042] Furthermore, the transfer device 1 in Embodiment 2 is provided with an engaging structure for a one-side index section 23 and a other-side index section 24 (see reference). Figures 12-17 (etc.). That is, the housing 15 is provided with a side indicator 23 that does not change its relative position with the second base, and the side indicator 23 engages with the other side indicator 24 that does not change its relative position with the first base at a position that can be seen.

[0043] More specifically, the one-side indicator portion 23 is the periphery of the elongated hole 23a in the side wall portion 18a of the housing 15. Furthermore, the elongated hole 23a is positioned at the center of the side wall portion 18a and is elongated in the third direction D3. Additionally, the other-side indicator portion 24 is a protrusion 24a extending vertically from the side surface 13a of the oil supply body 8.

[0044] Furthermore, the elongated hole 23a and the protrusion 24a are configured such that the protrusion 24a can penetrate the elongated hole 23a and move along the third direction D3. In the unused state, that is, when the cylindrical surface 11 of the oil supply body 8 has not been worn down due to wear, the protrusion 24a engages with the wall on the top wall 17 side of the inner wall of the elongated hole 23a. However, as the cylindrical surface 11 is worn down due to wear and retracts towards the flat surface 12, the protrusion 24a separates from the wall on the top wall 17 side and moves towards the opening side of the housing 15.

[0045] [Adjustment Method in Example 2] Using Figures 13-15The method for adjusting the oil supply capacity of the transmission device 1 in Embodiment 2 will be described. For example, when the cylindrical surface 11 retracts by a length L toward the flat surface 12 due to wear, etc., and the coil springs 9a, 9b, and 9c extend by a length L along the third direction D3, the pressing force of the cylindrical surface 11 on the needle roller 4 weakens, and the oil supply capacity to the needle roller 4 decreases (see reference). Figure 13 , Figure 14 wait).

[0046] In this state, the protrusion 24a separates from the wall on the side of the top wall portion 17. Therefore, the threaded fastener at the fastening allowance 19 is loosened, and the housing 15 travels a length L along the third direction D3. As a result, the elongated hole 23a travels a length L along the third direction D3, and the wall on the side of the top wall portion 17 in the inner wall of the elongated hole 23a engages with the protrusion 24a (see reference). Figure 15 As a result, the lengths of the coil springs 9a, 9b, and 9c are restored to their unused state, thus restoring the pressing force of the cylindrical surface 11 on the needle roller 4 and the oil supply capacity to the needle roller 4.

[0047] [Effects of Embodiment 2] According to the transmission device 1 of Embodiment 2, the second base is disposed on the housing 15 itself. Therefore, by moving the housing 15 forward and backward along the third direction D3, the coil springs 9a, 9b, and 9c can move forward and backward relative to the oil supply body 8 along the third direction D3, thereby adjusting the oil supply capacity. Furthermore, the threaded hole 19a at the fastening allowance 19 is a longer hole in the third direction D3. Therefore, by loosening the threaded fastening at the fastening allowance 19 and moving the housing 15 forward and backward along the third direction D3, the oil supply capacity can be adjusted.

[0048] Furthermore, according to the transfer device 1 of Embodiment 2, the wall on the side of the top wall portion 17 in the inner wall of the open space 23a of the housing 15 engages with the protrusion 24a provided in the oil supply body 8 at a visually perceptible position. Moreover, in the oil supply body 8, when the cylindrical surface 11 is worn down and retracts, for example, due to wear, the protrusion 24a separates from the wall on the side of the top wall portion 17. Therefore, by visually observing the separation width between the protrusion 24a and the wall on the side of the top wall portion 17, it is possible to determine whether to adjust the oil supply capacity.

[0049] Furthermore, according to the adjustment method of the transmission device 1 in Embodiment 2, when the protrusion 24a separates from the wall on the top wall 17 side due to the retraction of the cylindrical surface 11, the housing 15 is moved forward and backward along the third direction D3 by loosening the threaded fastener at the fastening allowance 19, thereby engaging the wall on the top wall 17 side with the protrusion 24a. Thus, the oil supply capacity can be restored visually.

[0050] [Example 3] The transfer device 1 according to Example 3 differs from the transfer device 1 of Example 1, such as... Figure 18As shown, pinion 2 meshes with spur gear 26. Furthermore, the structure of the oil supply unit 7 is the same as in Embodiment 1. Additionally, the second direction D2 is, for example, set to be perpendicular to a straight line orthogonal to both the rotation axis of pinion 2 and the rotation axis of spur gear 26. With such a transmission device 1, the same effect as in Embodiment 1 can be achieved.

[0051] [Structure of Embodiment 4] The transfer device 1 according to Embodiment 4 differs from the transfer devices 1 of Embodiments 1 to 3, as follows: Figure 19 As shown, the oil supply section 7 does not have a force application unit 9. Through the elasticity of the oil supply body 8 itself, the cylindrical surface 11 contacts and presses against the outermost periphery of the needle roller 4. That is, the oil supply body 8 is, for example, obtained by impregnating oil with foaming resin, with one side of its flat surface 12 housed within the housing 15. Through the elasticity of the oil supply body 8 itself, the cylindrical surface 11 presses against the outermost periphery of the needle roller 4, and the flat surface 12 presses against the top wall portion 17. Therefore, fluctuations in the pressing force of the cylindrical surface 11 against the needle roller 4 can be suppressed, thus suppressing the decrease in the oil supply capacity to the needle roller 4.

[0052] [Modifications] Various modifications can be considered within the scope of the present invention without departing from its spirit. For example, in the transmission device 1 of Embodiment 1 and Embodiment 2, the pinion 2 is driven to rotate so that the pinion 2 travels along the rack 3. However, the pinion 2 can also be driven to rotate while its position is fixed so that the rack 3 travels. In addition, the transmission device 1 can be configured to mesh with gears other than the rack 3 and the spur gear 26.

[0053] Furthermore, in the transmission device 1 of Embodiments 1-3, the force-applying unit 9 is a coil spring as the force-applying member. However, in addition to a coil spring, a leaf spring or an elastomer such as rubber can also be used as the force-applying member. Furthermore, the force-applying unit 9 can also be structured without using such a force-applying member. For example, it can be configured to maintain the airtightness of the space formed between the flat surface 12 of the oil supply body 8 and the top wall portion 17 of the housing 15, and pressurized air with a specific pressure can be supplied to this space to apply force to the oil supply body 8. Furthermore, in the transmission device 1 of Embodiments 1-3, the oil supply body 8 is an oil-containing resin, but solid grease or oil-containing metal can also be used as the oil supply body 8.

[0054] Furthermore, in the transmission device 1 according to Embodiments 1 to 3, the advance / retreat unit moves the force-applying member such as the coil spring 9a forward and backward when the cylindrical surface 11 is reduced and retracted due to wear, etc. However, the use of the advance / retreat unit is not limited to the retraction of the cylindrical surface 11. For example, during the manufacture of the transmission device 1, the advance / retreat unit can be used to move the force-applying member forward and backward when adjusting the set force of the force-applying member. In addition, in the transmission device 1 according to Embodiments 1 to 3, the second direction D2 is consistent with the travel direction of the pinion 2, but the shape of the second direction D2 is not limited to Embodiments 1 and 2, and the second direction D2 can also be inclined relative to the travel direction of the pinion 2. Symbol Explanation

[0055] 1. Transmission device (driving force transmission device); 2. Pinion; 3. Rack (other gears); 4. Needle roller; 7. Oil supply unit; 11. Cylindrical surface; 8. Oil supply body; 9. Force application unit; D1. First direction; D2. Second direction; D3. Third direction.

Claims

1. A driving force transmission device, comprising a pinion that meshes with other gears and an oil supply unit for supplying oil to the pinion, In the pinion, a plurality of cylindrical needle rollers are arranged parallel to the axis of rotation of the pinion and in a cylindrical shape, with each needle roller serving as a tooth tip that meshes with the other gears. The driving force transmission device is characterized in that... The oil supply unit has: An oil supply body, which is the source of oil supplied to the needle rollers, and having a cylindrical surface having a radius substantially the same as the radius of revolution of the outermost circumference of the needle rollers when the pinion rotates; and A force-applying unit applies force to the oil supply body so that the cylindrical surface contacts the outermost periphery of the needle roller. As the pinion rotates, the outermost circumference of the needle roller slides onto the cylindrical surface, thereby supplying oil from the oil supply body to the needle roller. When the axis of rotation of the pinion is referred to as the first direction, and the direction of a specific tangent in the circle traced by the outermost circumference of the needle roller during its revolution is referred to as the second direction, The force-applying unit applies force to the oil supply body at at least two locations along a third direction perpendicular to both the first and second directions.

2. The driving force transmission device according to claim 1, characterized in that, The force-applying unit includes a force-applying component, which applies force to the oil supply body in the third direction through the elastic force generated by its own flexure. The oil supply unit has a retraction unit that causes the force-applying member to retract relative to the oil supply body in the third direction.

3. The driving force transmission device according to claim 1, characterized in that, The force-applying unit includes a force-applying component, which applies force to the oil supply body in the third direction through the elastic force generated by its own flexure. The oil supply unit has a base forming member, which includes a second base. The second base, together with a first base disposed on one side of the oil supply body, clamps the force-applying member in the third direction and generates an elastic force. By moving the base forming member forward and backward along the third direction, the force-applying member can be moved forward and backward relative to the oil supply body along the third direction. Furthermore, the base forming member is provided with an index portion on one side that does not change its relative position to the second base. The indicator part on one side engages with the indicator part on the other side, which does not change its relative position to the first base, at a position that is visible to the naked eye. When the cylindrical surface is cut and retracted in the oil supply body, the other side indicator part separates from the first side indicator part.

4. A method for adjusting a driving force transmission device, which is the method for adjusting a driving force transmission device as described in claim 3, characterized in that, When the other side indicator part separates from the one side indicator part due to the retraction of the cylindrical surface, the one side indicator part is engaged with the other side indicator part by moving the base forming member forward and backward along the third direction.

5. A driving force transmission device, comprising a pinion that meshes with other gears and an oil supply body for supplying oil to the pinion, wherein a plurality of cylindrical needle rollers are arranged parallel to the axis of rotation of the pinion and in a cylindrical shape, and each needle roller meshes with the other gears as a tooth tip, the driving force transmission device being characterized in that... The oil supply body is the source of oil supplied to the needle rollers, and has a cylindrical surface having a radius that is substantially the same as the radius of revolution of the outermost circumference of the needle rollers when the pinion rotates. When the axis of rotation of the pinion is referred to as the first direction, and the direction of a specific tangent in the circle traced by the outermost circumference of the needle roller during its revolution is referred to as the second direction, The cylindrical surface is pushed out along a third direction perpendicular to the first and second directions by the elasticity of the oil supply body, so that the cylindrical surface contacts the outermost periphery of the needle roller.

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