Balancer device

Abstract

The present disclosure provides a balancer device capable of reducing noise while ensuring durability. The balancer device (1) includes: a driven gear (2) engaged with a driving gear (100) in an internal combustion engine, the driving gear (100) being a helical gear connected to a crankshaft; a balance shaft (3) connected to the driven gear (2) in a manner rotatable with the driven gear (2); and a force applying portion (4) provided between the driven gear (2) and the balance shaft (3). The driven gear (2) is a helical gear, thereby configured to generate a thrust force (F1) in one side (a direction) of an axial direction (x2) when engaged with and rotated by the driving gear (100), and the force applying portion (4) is capable of applying an acting force (F2) in the other side (b direction) of the axial direction (x2) to the driven gear (2).

Description

Technical Field

[0001] This invention relates to a balancer device. Background Technology

[0002] Previously, a balancer device for reducing vibrations caused by rotation in an internal combustion engine has been proposed, in which annular grooves are provided on both surfaces of the gears (for example, see Patent Document 1). In the balancer device described in Patent Document 1, vibrations generated between the gears are absorbed by forming annular grooves on the gears, thereby reducing grinding noise.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-134230 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, when the gear is prone to deformation due to the grooves formed as described in Patent Document 1, the durability of the gear tends to decrease. That is, in a structure that uses the deformation of the gear to absorb vibration, if it is easy to deform, the durability decreases; if it is difficult to deform, it is difficult to absorb vibration, making it difficult to balance noise reduction and durability.

[0008] The present invention was made in view of the above-mentioned problems, and its object is to provide a balancer device that can reduce noise while ensuring durability.

[0009] Solutions for solving technical problems

[0010] To achieve the above objectives, the balancer device of the present invention includes: a driven gear that meshes with a driving gear in an internal combustion engine, the driving gear being a helical gear connected to a crankshaft; a balance shaft connected to the driven gear in a manner capable of rotating together with the driven gear; and a force-applying part disposed between the driven gear and the balance shaft, the driven gear being a helical gear configured to generate a thrust in the axial direction when meshing and rotating with the driving gear, the force-applying part being capable of applying a force in the axial direction to the driven gear on the other side.

[0011] In one embodiment of the balancer device of the present invention, an intermediate member is provided between the force-applying part and the driven gear. The intermediate member is configured to move along the axial direction together with the driven gear, and in the rotating state of the driven gear, it can restrict movement to one side by abutting against the balance shaft.

[0012] In one embodiment of the balancer device of the present invention, the force-applying part is configured to have an annular elastic member, the inner peripheral surface of the elastic member is fixed to the balance shaft side and the outer peripheral surface is fixed to the driven gear side, and the elastic member tilts towards the other side as it moves towards the outer peripheral side when the driven gear is in a stopped state.

[0013] Invention Effects

[0014] The balancer device according to the present invention can reduce noise while ensuring durability. Attached Figure Description

[0015] Figure 1 This is a perspective view showing the driven gear of a balancer device according to an embodiment of the present invention.

[0016] Figure 2 This is a cross-sectional view showing the driven gear in a stopped state in the balancer device according to an embodiment of the present invention.

[0017] Figure 3 This is a cross-sectional view showing the configuration in which the driven gear is in a rotating state in the balancer device according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures

[0019] 1…balancer device, 2…driven gear, 21…through hole, 3…balance shaft, 31…expanded diameter section, 4…force application section, 41…inner peripheral side connection section, 42…outer peripheral side connection section, 43…elastic member, 5…intermediate member, 51…cylindrical section, 52…annular section, 53…outer peripheral surface, 100…drive gear Detailed Implementation

[0020] The following is a reference to the appendix. Figure 1 The embodiments of the present invention will be described below. For example... Figures 1-3 As shown, the balancer device 1 according to an embodiment of the present invention includes: a driven gear 2 that meshes with a driving gear 100 in an internal combustion engine, the driving gear 100 being a helical gear connected to a crankshaft; a balance shaft 3 connected to the driven gear 2 in a manner that allows it to rotate together with the driven gear 2; and a force-applying part 4 disposed between the driven gear 2 and the balance shaft 3. The driven gear 2 is a helical gear, thereby being configured to generate a thrust F1 in one direction (a direction) toward the axis x2 when meshing and rotating with the driving gear 100, and the force-applying part 4 is capable of applying a force F2 to the driven gear 2 in the other direction (b direction) toward the axis x2.

[0021] A balancer device 1 is provided in an internal combustion engine, which includes a crankshaft and a drive gear 100, which is a helical gear connected to the crankshaft. That is, when the crankshaft rotates, the drive gear 100 also rotates. The axis x1 of the drive gear 100 (i.e., the central axis of the crankshaft) extends parallel to the axis x2 of the driven gear 2 (i.e., the central axis of the balance shaft 3). Hereinafter, for ease of explanation, arrow a (refer to...) in the directions of axes x1 and x2 will be... Figures 1-3 The direction is set to one side, and arrow b (refer to) will be placed in the x-direction of the axis. Figure 1 The direction is set to the other side. Furthermore, the direction in which axes x1 and x2 are aligned is set to the Z direction, and the direction orthogonal to axes x1, x2, and the Z direction is set to the Y direction. In the following description, the positional relationships and directions of the components are shown only in the accompanying drawings and do not represent the positional relationships and directions when assembled into an actual vehicle, etc.

[0022] The driving gear 100 is a helical gear, which has the ability to change direction with orientation. Figure 1 The drive side is tilted towards direction b (the other side) from the positive rotation direction R1. Furthermore, the drive gear 100 is preferably made of resin, but it may also be made of metal materials such as iron.

[0023] In addition to the driven gear 2, balance shaft 3, force application part 4, the balancer device 1 also includes an intermediate component 5.

[0024] Driven gear 2 is a helical gear, which has the characteristic of changing direction with the direction of rotation. Figure 1 The driven gear 2 is tilted towards direction b (the other side) from the positive rotation direction R2. It should be noted that when the driving gear 100 rotates in the positive rotation direction R1, the driven gear 2 rotates in the positive rotation direction R2. Furthermore, the driven gear 2 is preferably made of resin, but it can also be made of metal materials such as iron. A circular through hole 21 extending along the axis x2 is formed in the center of the driven gear 2.

[0025] The driving gear 100 and driven gear 2 are helical gears, thus generating a thrust that separates them in the directions of axes x1 and x2 when they rotate. With the aforementioned inclined orientation, during rotation in the positive directions R1 and R2, the driven gear 2 experiences a force from the driving gear 100 in the direction a (one side), and the driving gear 100 experiences a force from the driven gear 2 in the direction b (the other side) (see reference). Figure 3 That is, the driven gear 2 is a helical gear, which generates a thrust F1 to one side in the direction of axis x2 when it meshes with and rotates with the driving gear 100.

[0026] The balance shaft 3 is a rod-shaped (cylindrical) member extending along the axis x2, and it passes through the through hole 21 of the driven gear 2. A flange-shaped enlarged diameter portion 31 is formed at the end of the balance shaft 3 in the a direction. That is, at the enlarged diameter portion 31, the balance shaft 3 protrudes outward from the portion where the force-applying portion 4 is connected, as described later. It should be noted that the enlarged diameter portion 31 can be formed as a continuous ring in the circumferential direction centered on the axis x2, or it can be provided only in a portion of the circumferential direction. In addition, the enlarged diameter portion 31 can be integrally formed with the balance shaft 3, or it can be constituted as a component different from the shaft body of the balance shaft 3 and assembled to the shaft body.

[0027] The force-applying part 4 includes: an inner peripheral connecting part 41 fixed to the outer peripheral surface of the balance shaft 3; an outer peripheral connecting part 42 fixed to the inner peripheral surface of the cylindrical part 51 of the intermediate member 5 (described later); and an elastic member 43 disposed between the inner peripheral connecting part 41 and the outer peripheral connecting part 42. That is, the inner peripheral surface of the elastic member 43 is fixed to the balance shaft 3 side via the inner peripheral connecting part 41, and the outer peripheral surface is fixed to the driven gear 2 side via the outer peripheral connecting part 42 and the intermediate member 5.

[0028] The elastic member 43 is composed of elastic components such as rubber and elastic elements, and is integrally formed into a cylindrical shape (in this embodiment, it is cylindrical) extending along the axis x2 direction. In addition, the elastic member 43 is inclined such that, in its natural state (undeformed state), it faces the b direction as it moves toward the outer peripheral side (i.e., the driven gear 2 side).

[0029] The intermediate member 5 is, for example, a resin gear insert, integrally formed as a cylindrical shape (in this embodiment, a cylindrical shape) extending along the axis x2. It is disposed on the outside of the balance shaft 3 and inside the through hole 21, and is radially positioned between the driven gear 2 and the balance shaft 3 with respect to the axis x2. The intermediate member 5 has a cylindrical portion 51 extending along the axis x2 and an annular portion 52 continuous with the a-direction end of the cylindrical portion 51. The annular portion 52 is a reduced-diameter portion extending from the cylindrical portion 51 toward the inner circumference.

[0030] The intermediate member 5 is fixed to the driven gear 2 while its outer peripheral surface 53 contacts the inner peripheral surface of the through hole 21 of the driven gear 2. Thus, the intermediate member 5 rotates together with the driven gear 2 when the driven gear 2 rotates, and the intermediate member 5 moves together with the driven gear 2 when the driven gear 2 moves along the axis x2.

[0031] The outer diameter of the balance shaft 3 is larger than the inner diameter of the annular portion 52 at the enlarged diameter portion 31, and smaller than the inner diameter of the annular portion 52 in the portion excluding the enlarged diameter portion 31. Furthermore, the annular portion 52 is positioned relative to the enlarged diameter portion 31 on the b-direction side. Therefore, when the balance shaft 3 is inserted into the intermediate member 5, and the intermediate member 5 moves a predetermined distance in the a-direction, the annular portion 52 comes into contact with the enlarged diameter portion 31, thus restricting its movement.

[0032] In the balancer device 1, the driven gear 2 is connected to the balance shaft 3 via the force-applying part 4 and the intermediate member 5. This allows the rotation of the driven gear 2 to be transmitted to the balance shaft 3, causing the driven gear 2 and the balance shaft 3 to rotate together. Furthermore, the driven gear 2 and the balance shaft 3 can move relative to each other in the x2 direction. Additionally, the driven gear 2, balance shaft 3, force-applying part 4, and intermediate member 5 are all arranged coaxially.

[0033] Here, details of the shape, configuration, and operation of each part of the balancer device 1 in both the non-rotating and rotating states of the drive gear 100 will be explained.

[0034] With the driving gear 100 not rotating, the driven gear 2 also remains stationary. Figure 2 This stopped state is equivalent to the assembled state in which the driven gear 2, balance shaft 3, force-applying part 4, and intermediate member 5 are assembled. In the stopped state of the driven gear 2, the elastic member 43 is in its natural state. It should be noted that the elastic member 43 can also be slightly deformed from its natural state, tilting in the same way as in its natural state, towards the outer periphery and towards direction b.

[0035] When the driving gear 100 rotates in the positive rotation direction R1, the driven gear 2 rotates in the positive rotation direction R2, thus entering a rotating state. Figure 3 At this time, a thrust F1 acts on the driven gear 2 as described above. Under the action of this thrust F1, the driven gear 2 and the intermediate member 5 move in the direction a. At this time, the balance shaft 3 does not move along the axis x2, while the driven gear 2 and the intermediate member 5 move while deforming the elastic member 43 of the force-applying part 4. Through the deformation of the elastic member 43, an action force F2 is generated under the action of the restoring force. The action force F2 is the force that wants to move the driven gear 2 and the intermediate member 5 in the direction b, and the distance by which the thrust F1 and the action force F2 move the driven gear 2 becomes equal.

[0036] When the driven gear 2 is rotating, it receives a thrust F1 from the driving gear 100 and a counterforce F2 from the force-applying part 4. As a result, the tooth surface of the driven gear 2 is pressed against the tooth surface of the driving gear 100 under the action of force F2, and remains in this pressed state. That is, backlash is reduced. When the rotational speed of the driving gear 100 changes, the driven gear 2 moves along the axis x2 according to the change in thrust F1, thus the force F2 also changes, maintaining contact between the tooth surface of the driven gear 2 and the tooth surface of the driving gear 100.

[0037] The magnitude of the thrust F1 depends on the rotational speed of the driving gear 100 and the driven gear 2. When the thrust F1 increases, the amount of movement of the driven gear 2 in the direction a also increases. When the rotational speed is a specified value and the driven gear 2 and the intermediate member 5 move a specified distance in the direction a, as described above, the annular portion 52 abuts against the expanded diameter portion 31, and the movement is restricted.

[0038] Thus, the balancer device 1 according to an embodiment of the present invention, by providing a force-applying part 4 capable of applying a force in the opposite direction to the thrust F1 to the driven gear 2, can reduce backlash and maintain contact between the gear tooth surfaces even with changes in rotational speed. This suppresses grinding noise between the driving gear 100 and the driven gear 2, reducing noise levels. Furthermore, there is no need to deform the gears themselves to reduce noise, thereby ensuring durability.

[0039] In addition, by utilizing the force-applying part 4 to reduce noise, for example, compared with structures using scissors gear, it is possible to reduce costs.

[0040] Furthermore, the intermediate member 5 abuts against the balance shaft 3, thereby limiting movement in the direction a, which in turn limits excessive movement when the rotational speed increases. This prevents the elastic member 43 from being damaged due to excessive deformation.

[0041] Furthermore, the elastic member 43 is tilted such that it faces the b direction towards the outer periphery when the driven gear 2 is stationary. When the driven gear 2 rotates, the elastic member 43 deforms in a compressed manner. Therefore, compared with a structure that deforms in a stretched manner, the possibility of the elastic member 43 breaking can be suppressed.

[0042] In addition, if the drive gear 100 is made of resin, it can mitigate the impact on the drive gear 100 and the driven gear 2 during rotation, thereby improving durability.

[0043] It should be noted that the present invention is not limited to the above-described embodiments, and also includes other structures that can achieve the purpose of the present invention. The variations shown below are also included in the present invention. For example, in the above-described embodiments, the intermediate member 5 abuts against the balance shaft 3 to restrict movement in the direction a. However, movement can also be restricted by the intermediate member abutting against components other than the balance shaft, or by the driven gear abutting against the balance shaft or other components. Furthermore, movement can be unrestricted, for example, when the rotational speed of the driven gear is difficult to increase and the amount of movement in the axial direction is small, or when the durability of the force-applying part is sufficiently high, and the elastic member is unlikely to be damaged.

[0044] Furthermore, in the above embodiment, the elastic member 43 is inclined in the direction b as it moves towards the outer periphery when the driven gear 2 is in the stopped state. However, the elastic member may not have such an inclination, or it may have an inclination in the opposite direction. In addition, the force-applying part can be any elastic member with a suitable shape, such as a coil spring or other elastic member.

[0045] Furthermore, in the above embodiment, the balancer device 1 includes only one balance shaft 3, but the balancer device may also include multiple balance shafts. That is, the balance shaft 3 in the above embodiment may also be used as the driving shaft, and a driven shaft that rotates with it may be provided.

[0046] While embodiments of the present invention have been described above, the present invention is not limited to the balancer device described in the above embodiments, but includes all the embodiments encompassed by the concept of the present invention and the patent claims. Furthermore, in order to enable at least some of the aforementioned problems and effects to function, the various structures may be selectively combined as appropriate. For example, the shape, material, arrangement, size, etc., of the structural elements of the above embodiments may be appropriately modified according to the specific usage of the present invention.

Claims

1. A balancing device, wherein, include: The driven gear meshes with the driving gear in the internal combustion engine. The driving gear is a helical gear connected to the crankshaft, and a circular through hole is formed in the center of the driven gear along the axial direction. A balance shaft is connected to the driven gear in a manner that allows it to rotate together with the driven gear, and is inserted through the through hole of the driven gear; and The force-applying part is located between the driven gear and the balance shaft. The driven gear is a helical gear, which is configured to generate a thrust in the axial direction when it meshes and rotates with the driving gear. The force-applying part can apply a force to the driven gear on the other side in the direction of the axis. An intermediate member is provided between the force-applying part and the driven gear. This intermediate member is positioned radially between the driven gear and the balance shaft, with the axis as a reference, by being disposed outside the balance shaft and inside the through hole. The intermediate member has a cylindrical portion extending along the axial direction and an annular portion continuous with one end of the cylindrical portion, the annular portion being a tapered portion extending from the cylindrical portion toward the balance shaft side. The force-applying part has: an inner peripheral connecting part, fixed to the outer peripheral surface of the balance shaft; and an outer peripheral connecting part, fixed to the inner peripheral surface of the cylindrical part of the intermediate member. An elastic member is disposed between the inner peripheral connecting portion and the outer peripheral connecting portion. The elastic member, in the stopped state of the driven gear, tilts toward the other side as it moves toward the driven gear side.

2. The balancer device according to claim 1, wherein, The intermediate member is configured to move along the axial direction together with the driven gear, and in the state of rotation of the driven gear, the movement of the intermediate member to one side can be restricted by abutting against the balance shaft.

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