JP2020051584A - transmission - Google Patents

Abstract

To reduce noise caused by resonance occurring in a space part between a case of a transmission and an external component fixed to the case from the outer side.SOLUTION: A transmission includes: a transmission mechanism; a case which houses the transmission mechanism; an exterior component fixed to the case from the outer side; a space part defined between an outer surface of the case and the exterior component; a cavity part formed at the case; and a communication passage which allows communication between the space part and the cavity part. The cavity part and the communication passage form a helmholtz resonator.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a transmission that includes a transmission mechanism and a case that houses the transmission mechanism.

  Conventionally, at least a pair of gears arranged inside the case, a resonance type silencer arranged at a corner above the meshing position of the gears inside the case, and an oil sump provided below the gear position Is known (for example, see Patent Document 1). The muffler of this transmission is configured by adding another wall to the two side walls forming the corners, and the center frequency of resonance is matched with the meshing frequency of the pair of gears. .

Japanese Patent No. 3184615

  In the above-mentioned conventional transmission, the noise of a specific frequency out of the noise generated by the engagement of the pair of gears inside the case can be reduced by the silencer, and the transmission to the outside of the case can be suppressed. However, the noise generated by the transmission is not limited to that generated inside the case, but is generated in a space (gap) between the case of the transmission and an exterior component fixed from the outside to the case. Noise due to resonance (spatial resonance) may be a problem.

  Therefore, an object of the present disclosure is to reduce noise due to resonance generated in a space between a case of a transmission and an exterior component fixed from the outside to the case.

  A transmission according to an embodiment of the present disclosure includes a transmission mechanism, a case accommodating the transmission mechanism, an exterior component fixed from the outside to the case, and an outer surface of the case and the exterior component. A transmission including a hollow portion formed in the case, and a communication path communicating the space portion with the hollow portion.

  In the transmission according to the present disclosure, the cavity formed in the case, and the communication path that communicates the space between the outer surface of the case and the exterior component with the cavity constitute a Helmholtz resonator. Thereby, the resonance frequency (natural frequency) of the Helmholtz resonator is adjusted to the resonance frequency generated in the space by adjusting the volume of the cavity, the cross-sectional area and the length of the communication path, etc. The noise due to the resonance can be favorably reduced without disposing a silencer outside.

1 is a schematic configuration diagram illustrating a transmission according to the present disclosure. FIG. 2 is a partial cross-sectional view illustrating a main part of the transmission according to the present disclosure. FIG. 11 is a partial cross-sectional view illustrating a main part of another transmission according to the present disclosure. FIG. 11 is a partial cross-sectional view illustrating a main part of still another transmission according to the present disclosure. FIG. 9 is a partial cross-sectional view illustrating a modified example of the case of the transmission according to the present disclosure.

  Next, an embodiment for carrying out the invention of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a transmission 1 according to the present disclosure. The transmission 1 shown in FIG. 1 changes the power from an internal combustion engine (engine) mounted on a vehicle and transmits the power to drive wheels. The transmission 1 includes a transmission mechanism 2 and a transmission case 3 that accommodates the transmission mechanism 2. And an electronic control unit (ECU) 4 for controlling the transmission mechanism 2 (a hydraulic control unit not shown). The transmission mechanism 2 is a stepped automatic transmission mechanism or a mechanical or electric continuously variable transmission mechanism. The transmission case 3 includes a first case 31 and a second case 32 formed by casting a metal material such as an aluminum alloy, for example, and an oil pan 33 is fixed below the first case 31. As shown in FIG. 2, the electronic control unit 4 includes a circuit board 40 on which an electronic circuit is mounted, and a resin case 41 formed so as to seal the circuit board 40 and the like. It is fixed to the one case 31 from outside via a bolt or the like (not shown).

  FIG. 2 is a partial cross-sectional view illustrating a main part of the transmission 1. As shown in the figure, the first case 31 of the transmission case 3 includes an outer wall 310 that covers the transmission mechanism 2 and the like, and a first end face 31 a formed at an end of the outer wall 310. In addition, the second case 32 includes a second end surface 32a that closely abuts against the first end surface 31a of the first case 31 (outer wall portion 310). The first and second cases 31, 32 are fixed (coupled) to each other via a bolt or the like (not shown) in a state where the first end face 31a and the second end face 32a abut each other. In the present embodiment, the electronic control device 4 as an exterior component is fixed to the outer wall 310 of the first case 31 from outside via a bolt or the like (not shown), and the electronic control device 4 and the outer surface of the outer wall 310 are connected to each other. A space portion X is defined between them.

  Further, as shown in FIG. 2, the outer wall portion 310 of the first case 31 is provided so as to be located inside the space X between the electronic control device 4 and the outer wall portion 310 (on the speed change mechanism 2 side). The bottom cylindrical protrusion 311 is formed by casting. The protruding portion 311 defines a concave portion 315 having a circular cross section that opens in the space portion X and is depressed inward (toward the transmission mechanism 2). The annular closing member 35 having the through hole H is screwed. As a result, a cavity Z is defined by the protruding portion 311 (outer wall portion 310) and the closing member 35 that closes the opening of the concave portion 315, and the through hole H of the closing member 35 as a communication passage allows the electronic control device 4 to communicate with the electronic control device 4. The space X and the cavity Z between the outer wall 310 are communicated with each other. The closing member 35 may be welded (joined) to the outer wall 310 so as to close the opening of the recess 315.

Here, when a space portion X is defined between the first case 31 (outer wall portion 310) and the electronic control device 4 as an exterior component fixed from the outside to the first case 31, the space is defined. Noise caused by resonance (spatial resonance) generated in the part X may be a problem. On the other hand, in the transmission 1, the cavity Z formed in the outer wall 310 of the first case 31, the space X between the electronic control unit 4 and the outer surface of the outer wall 310, and the cavity Z And a through-hole H as a communication path for communicating with the device constitutes a Helmholtz resonator. Further, the resonance frequency (natural frequency) f _hr of such a Helmholtz resonator is represented by the following equation (1). In the equation (1), “C” is the speed of sound, “S” is the cross-sectional area of the through-hole H, “V” is the volume of the cavity Z, and “L” is the through-hole. The length (axial length) of the hole H, and “r” is the radius of the through hole H. Therefore, in the transmission 1, the resonance frequency f _hr of the Helmholtz resonator is adjusted in the space X by adjusting the volume V of the cavity Z and the sectional area S, the radius r, and the length L of the through hole H. By matching (matching) the frequency, it is possible to reduce noise due to the resonance satisfactorily without disposing a silencer outside the transmission case 3.

f _hr = C · 2π · √ (S / (V · (L + 1.7r))) (1)

Further, in the transmission 1, the closing member 35 is joined (screw-fit) to the opening of the concave portion 315 formed in the outer wall 310 so as to open in the space X and to be depressed inward (toward the transmission mechanism 2). A cavity Z is defined by the outer wall 310 and the closing member 35, and the space X and the cavity Z are communicated by a through hole H formed in the closing member 35. Thereby, the interference between the first case 31 and the electronic control unit 4 as the exterior component is effectively reduced while eliminating the interference between the transmission 1 and the surrounding members. It becomes possible. Further, since the volume V of the cavity Z and the length L of the through hole H can be adjusted by changing the thickness of the closing member 35, the resonance frequency f _hr of the Helmholtz resonator is changed to the resonance frequency generated in the space X. Satisfactorily. Further, in the transmission 1, the concave portion 315, that is, the cavity Z is defined so as not to communicate with the inside of the transmission case 3 (the accommodation space of the transmission mechanism 2). ) Does not leak out of the transmission case 3 through the through hole H of the closing member 35.

  FIG. 3 is a partial cross-sectional view illustrating a main part of another transmission 1 </ b> B of the present disclosure. Note that, among the components of the transmission 1B, the same components as those of the above-described transmission 1 are denoted by the same reference numerals, and redundant description will be omitted. In the transmission 1B shown in FIG. 3, the first case 31B of the transmission case 3 is located inside the space X between the electronic control unit 4 and the outer wall 310 (on the side of the transmission mechanism 2) to form the hollow part Z. Includes a defining protrusion 311B. The protruding portion 311B is formed by an extending portion 310e that extends further inward (toward the transmission mechanism 2) from the inner surface of the outer wall portion 310. That is, the extension 310e is bent together with the outer wall 310 so as to define the cavity Z, and the free end of the extension 310e is tightly joined to the inner surface of the outer wall 310 by welding. As a result, a cavity Z is defined between the extension 310e and the inner surface of the outer wall 310. In the outer wall 310, a through-hole H having a circular cross section is formed as a communication path for communicating the space X and the cavity Z between the electronic control device 4 and the outer wall 310.

In such a transmission 1B, the cavity Z defined by the outer wall 310 and the extension 310e of the first case 31B and the through hole H formed in the outer wall 310 constitute a Helmholtz resonator. Thereby, the resonance frequency f _hr of the Helmholtz resonator is adjusted to the resonance frequency generated in the space X by adjusting the volume V of the cavity Z and the sectional area S, the radius r, and the length L of the through hole H ( By doing so, it is possible to eliminate interference between the transmission 1 </ b> B and members around the transmission 1 </ b> B, and to favorably reduce noise due to the resonance without disposing a muffler outside the transmission case 3. . Further, the transmission 1B, it is possible to adjust the volume V of the cavity portion Z by changing the extending length of the extending portion 310e, favorably to the frequency of resonance for generating the resonance frequency f _hr in space X It becomes possible to match. Further, in the transmission 1B, the free end of the extension 310e that defines the cavity Z is tightly joined to the inner surface of the outer wall 310 by welding. Oil) does not leak out of the transmission case 3 through the cavity Z and the through hole H.

  FIG. 4 is a partial cross-sectional view illustrating a main part of still another transmission 1 </ b> C of the present disclosure. Note that, among the components of the transmission 1C, the same components as those of the above-described transmission 1 and the like are denoted by the same reference numerals, and redundant description will be omitted. In the transmission 1C shown in FIG. 4, the first case 31C of the transmission case 3 is opened only at the first end face 31a, and is inside the space X between the electronic control unit 4 and the outer wall 310 (on the side of the transmission mechanism 2). ), And a through hole H formed in the outer wall portion 310 so as to communicate the inside of the hole portion 310Z and the space portion X with each other. When the first and second cases 31C and 32 are fixed to each other, the opening of the hole 310Z is closed by the second end face 32a abutted against the first end face 31a. As a result, a cavity Z communicating with the space X via the through hole H as a communication passage is defined in the transmission case 3. In the present embodiment, the hole 310Z is formed, for example, in a circular cross-section, but the cross-sectional shape of the hole 310Z is not limited to this, and is arbitrarily determined.

In such a transmission 1C, the hollow portion Z defined by the hole 310Z of the first case 31C and the second end surface 32a of the second case 32, and the through hole H formed in the outer wall portion 310 form a Helmholtz resonator. Constitute. Thereby, the resonance frequency f _hr of the Helmholtz resonator is adjusted to the resonance frequency generated in the space X by adjusting the volume V of the cavity Z and the sectional area S, the radius r, and the length L of the through hole H ( By doing so, it is possible to eliminate interference between the transmission 1 </ b> C and its surrounding members, and to reduce noise due to the resonance satisfactorily without disposing a muffler outside the transmission case 3. . Further, in the transmission 1C, the volume V of the cavity Z can be adjusted by changing dimensions such as the cross-sectional area (inner diameter) and the length of the hole 310Z, so that the resonance frequency f _hr of the Helmholtz resonator is changed to the space X. Can be satisfactorily tuned to the frequency of the resonance that occurs. Further, in the transmission 1 </ b> C, the opening of the hole 310 </ b> Z that defines the cavity Z is closed by the second end surface 32 a closely abutting on the first end surface 31 a, so that the lubricating oil supplied to the transmission mechanism 2 is provided. (Hydraulic oil) does not leak out of the transmission case 3 through the cavity Z and the through hole H. When the electronic control device 4 as an exterior component is fixed to the second case 32 from the outside, a hole defining the cavity Z may be formed in the second case.

  In the transmissions 1, 1B, and 1C, the transmission case 3 may be replaced with a transmission case 3D shown in FIG. The transmission case 3D shown in FIG. 5 includes an outer wall portion 300 that covers a transmission mechanism and the like and external components such as an electronic control unit are fixed from the outside, a cavity Z and a communication passage P, and the cavity Z is a communication passage. And a resonance container 30 which is screwed or welded to the outer wall portion 300 from the inside so as to communicate with the space portion X via P. Also in the transmission 1 and the like including the transmission case 3D, the interference between the transmission 1 and the like and the surrounding members is eliminated, and the resonance generated in the space X without disposing the muffler outside the transmission case 3D. Noise can be satisfactorily reduced. Further, the exterior component fixed to the transmission cases 3 and 3D via the space X may be a component other than the electronic control device 4, such as a hydraulic control device (valve body).

  As described above, the transmission according to the present disclosure includes the transmission mechanism (2), the case (3, 3D) that houses the transmission mechanism (2), and the externally fixed to the case (3, 3D). (1, 1B, 1C) including an exterior part (4) to be formed and a space (X) defined between an outer surface of the case (3, 3D) and the exterior part (4). ), Including a cavity (Z) formed in the case (3, 3D), and a communication path (H, P) for communicating the space (X) with the cavity (Z). It is a thing.

  In the transmission according to the present disclosure, the cavity formed in the case, and the communication path that communicates the space between the outer surface of the case and the exterior component with the cavity constitute a Helmholtz resonator. Thereby, the resonance frequency (natural frequency) of the Helmholtz resonator is adjusted to the resonance frequency generated in the space by adjusting the volume of the cavity, the cross-sectional area and the length of the communication path, etc. The noise due to the resonance can be favorably reduced without disposing a silencer outside.

  The case (3) includes an outer wall portion (310) that covers the transmission mechanism (2) and to which the exterior component (4) is fixed from the outside. And a recess (315) formed in the outer wall (310), the opening of the recess (315) defining a closure (Z) with the outer wall (310). (35), and the communication path (H) may be formed in the closing member (35). Accordingly, it is possible to satisfactorily reduce noise due to resonance generated in the space between the case and the exterior component while eliminating interference between the transmission and members around the transmission. In addition, in such a transmission, since the volume of the cavity and the length of the communication path can be adjusted by changing the thickness of the closing member, the resonance frequency of the Helmholtz resonator is changed to the resonance frequency generated in the space. Good matching can be achieved.

  The case (3) further includes an outer wall (310) that covers the transmission mechanism (2) and to which the exterior component (4) is fixed from the outside, and extends inward from the inner surface of the outer wall (310). An extended portion (310e) which is bent together with the outer wall portion (310) so as to define the hollow portion (Z) and whose free end is joined to the inner surface. 310e) and a through hole (H) formed in the outer wall portion (310) so as to function as the communication passage. Also in such a transmission, it is possible to satisfactorily reduce noise due to resonance generated in a space between the case and the exterior component while eliminating interference between the transmission and members around the transmission. In addition, in such a transmission, since the volume of the cavity can be adjusted by changing the extension length of the extension, the resonance frequency of the Helmholtz resonator can be favorably adjusted to the resonance frequency generated in the space. It becomes possible to match.

  The case (3) has a first case (31C) having a first end face (31a), a second end face (32a), and has the first end face (31a) and the second end face (32a). And a second case (32) fixed to the first case (31C) in a state in which the first and second cases (31, 32) are in contact with each other. A hole (2) formed to open at the two end surfaces (31a, 32a) and closed by the second or first end surface (31a, 32a) so as to define the cavity (Z). 310Z) and a through hole (H) functioning as the communication path. Also in such a transmission, it is possible to satisfactorily reduce noise due to resonance generated in a space between the case and the exterior component while eliminating interference between the transmission and members around the transmission. In addition, in such a transmission, since the volume of the cavity can be adjusted by changing the dimensions of the hole, the resonance frequency of the Helmholtz resonator can be satisfactorily adjusted to the resonance frequency generated in the space. Becomes

  Further, the case (3D) covers the transmission mechanism (2) and the outer wall portion (300) to which the exterior component (4) is fixed from the outside, the hollow portion (Z) and the communication passage (P). And a container (30) joined from the inside to the outer wall (300).

  Further, the exterior component may be a control device (4) for controlling the speed change mechanism (2). However, the exterior component may be a component other than the control device of the transmission mechanism.

  The invention of the present disclosure is not limited to the above embodiment at all, and it goes without saying that various changes can be made within the scope of the present disclosure. Furthermore, the form for carrying out the above-described invention is merely a specific form of the invention described in the section of the means for solving the problem, and is described in the section of the means for solving the problem. It does not limit the elements of the invention.

  The invention of the present disclosure can be used in the transmission manufacturing industry and the like.

  1, 1B, 1C transmission, 2 transmission mechanism, 3, 3D transmission case, 30 resonance container, 31, 31B, 31C first case, 31a first end face, 32 second case, 32a second end face, 33 oil pan, 35 closing member, 300, 310 outer wall, 310Z hole, 310e extension, 311, 311B protrusion, 315 recess, 4 electronic control unit, 40 circuit board, 41 resin case, H through hole, P communication path, X Space, Z cavity.

Claims (6)

A speed change mechanism including a speed change mechanism, a case accommodating the speed change mechanism, an exterior component fixed to the case from outside, and a space defined between an outer surface of the case and the exterior component. Machine,
A cavity formed in the case;
A communication passage for communicating the space and the cavity,
Transmission equipped with. The transmission according to claim 1,
The case includes an outer wall portion that covers the transmission mechanism and the exterior component is fixed from the outside, and a concave portion formed in the outer wall portion so as to be opened in the space portion and depressed inward,
The opening of the recess is closed by a closing member that defines the cavity together with the outer wall,
The transmission, wherein the communication passage is formed in the closing member. The transmission according to claim 1,
The case includes an outer wall portion that covers the transmission mechanism and the exterior component is fixed from the outside, and an extension portion that extends inward from an inner surface of the outer wall portion, and the hollow portion together with the outer wall portion. A transmission comprising: an extension portion which is bent so as to define a free end portion and a free end portion is joined to the inner surface; and a through hole formed in the outer wall portion so as to function as the communication passage. The transmission according to claim 1,
The case includes a first case having a first end face, and a second case having a second end face and fixed to the first case in a state where the first end face and the second end face abut against each other. ,
One of the first and second cases is formed to be open at the first or second end face, and the opening is closed by the second or first end face so as to define the cavity. A transmission including a hole and a through hole functioning as the communication path. The transmission according to claim 1,
The transmission includes an outer wall that covers the transmission mechanism and to which the exterior component is fixed from the outside, and a container that has the cavity and the communication path and is joined to the outer wall from the inside.   The transmission according to any one of claims 1 to 5, wherein the exterior component is a control device that controls the transmission mechanism.

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