Vehicular transmission

A vehicle transmission having a valve body disposed adjacently to and in parallel with a side cover covering a front or rear side or a side surface of a transmission case in a vehicle width direction in a vehicle-mounted state, the side cover connected to the transmission case, in which an electromagnetic valve is included on the side cover side of the valve body, when viewed in a direction horizontal and parallel to mating surfaces of the transmission case and the side cover, a strainer for removing a foreign material in a hydraulic oil is disposed between the side cover and the valve body to overlap with at least a portion of the electromagnetic valve, and the strainer has an inflow portion for allowing the hydraulic oil to flow in disposed vertically above an oil surface.

TECHNICAL FIELD

The present invention relates to a vehicle transmission and particularly to a vehicle transmission in which a valve body disposed in the transmission to control a hydraulic pressure supplied to a hydraulic actuator etc. is disposed on the front or rear side of a vehicle or the vehicle width side.

BACKGROUND ART

A transmission is achieved that has a valve body disposed on the front or rear side of the transmission or on the vehicle width side in a vehicle-mounted state i.e., in a state where the valve body is mounted on the vehicle with a valve body cover (side cover) connected to the valve body so as to cover the valve body. For example, a transmission of Patent Document 1 is an example thereof. In the transmission of Patent Document 1, a valve body 11 is disposed on the vehicle front side relative to a transmission mechanism, and an oil pan 3 (a valve body cover, a side cover) defined as a portion of the transmission case 1 is connected to cover the valve body 11.

PRIOR ART DOCUMENTS

Patent Documents

SUMMARY OF THE INVENTION

Problem to Be Solved by the Invention

From the view point of improvement of fuel efficiency, a consumption flow rate is further reduced in a hydraulic pressure control device including an electromagnetic valve. Means of reducing a consumption flow rate of a hydraulic pressure control device include making a valve clearance smaller in a valve including an electromagnetic valve. If the valve clearance is made smaller in this way and a foreign material enters the inside of a hydraulic circuit, the occurrence of valve stick becomes notable. Therefore, it is important to improve a filtering efficiency of a strainer in the hydraulic pressure control device. To suppress a loss at an oil pump while ensuring a filtering efficiency of a strainer, the strainer must be made larger. However, as transmissions are reduced in size, a larger strainer causes a problem that it becomes difficult to mount a strainer on a transmission.

The present invention was conceived in view of the situations and it is therefore an object of the present invention to provide a structure of a vehicle transmission improving a mountability of a strainer in a vehicle transmission having a valve body disposed on the front or rear side of a vehicle or on the vehicle width side.

Solution to Problem

To achieve the above object, a first aspect of the invention provides a vehicle transmission (a) having a valve body disposed adjacently to and in parallel with a side cover covering a front or rear side or a side surface of a transmission case in a vehicle width direction in a vehicle-mounted state, the side cover connected to the transmission case, wherein (b) an electromagnetic valve is included on the side cover side of the valve body, (c) when viewed in a direction horizontal and parallel to mating surfaces of the transmission case and the side cover, a strainer for removing a foreign material in a hydraulic oil is disposed between the side cover and the valve body to overlap with at least a portion of the electromagnetic valve, and (d) the strainer has an inflow portion for allowing the hydraulic oil to flow in disposed vertically above an oil surface (oil level).

A second aspect of the invention provides the vehicle transmission recited in the first aspect of the invention, wherein (a) a first space is formed between the side cover and the strainer, (b) a filter for filtering is disposed in the first space, (c) the strainer has an outflow portion disposed vertically under the oil surface, (d) the hydraulic oil flowing into the first space from the inflow portion passes through the filter and flows out from the outflow portion, and (e) the hydraulic oil flowing out from the outflow portion is supplied through the valve body to a lubrication required portion.

A third aspect of the invention provides the vehicle transmission recited in the first aspect of the invention, wherein (a) a first space is formed between the side cover and the strainer, (b) a filter for filtering is disposed in the first space, (c) at least one oil outflow hole is formed at positions lower than the inflow portion in the vertical direction of the strainer, (d) the hydraulic oil flowing into the first space from the inflow portion passes through the filter and flows out from the oil outflow hole, and (e) the hydraulic oil flowing out from the oil outflow hole is discharged to a second space on the transmission case side.

A fourth aspect of the invention provides the vehicle transmission recited in the second or third aspect of the invention, wherein (a) the filter is disposed in the vertical direction, and the first space is divided into two spaces by disposing the filter in the vertical direction.

Advantageous Effects of the Invention

According to the vehicle transmission recited in the first aspect of the invention, since the space is utilized that is formed by disposing the electromagnetic valves on the side cover side of the valve body between the side cover and the valve body and the strainer is disposed in the space at a position without interference of the electromagnetic valves, the strainer can be disposed without expanding the side cover. Since the inflow portion for the hydraulic oil is disposed vertically above the oil surface of the strainer, the filtering can be performed by using gravity and the hydraulic pressure loss (pressure loss) of the hydraulic oil can be reduced.

According to the vehicle transmission recited in the second aspect of the invention, since the hydraulic oil flowing into the first space passes through the filter and flows out from the outflow portion disposed vertically under the oil surface and is then supplied through the valve body to a lubrication required portion, the hydraulic oil filtered by the filter is supplied to the lubrication required portion. Since the inflow portion is disposed at a position vertically higher than the oil surface, the filtering can be performed by using gravity.

According to the vehicle transmission recited in the third aspect of the invention, since the hydraulic oil flowing into the first space passes through the filter and flows out from the oil outflow hole and is then discharged to the second space on the transmission case side, the hydraulic oil filtered by the filter is discharged to and accumulated in the second space on the transmission case side. Since the inflow portion is disposed at a position vertically higher than the oil outflow hole, the filtering can be performed by using gravity.

According to the vehicle transmission recited in the fourth aspect of the invention, the filter is disposed in the vertical direction. Consequently, the first space is vertically divided into two spaces and a foreign material in the hydraulic oil is effectively removed by the filter even during a transition period in which the hydraulic oil flowing into the first space from the inflow portion moves vertically downward due to gravity.

MODE FOR CARRYING OUT THE INVENTION

An example of the present invention will now be described in detail with reference to the drawings. In the following example, the figures are simplified or deformed as needed and portions are not necessarily precisely shown in terms of dimension ratio, shape, etc.

Example

FIGS. 1A to 1Dshow a structure of connection of a valve body12acting as a portion of a vehicle transmission10to which the present invention is preferably applied, specifically, as a portion of a hydraulic pressure control device of the vehicle transmission10, to a transmission case14.FIG. 1Ashows a state in which the valve body12is connected to the transmission case14of the vehicle transmission10.FIG. 1Bis an arrow view taken in the direction of an arrow A ofFIG. 1Aand shows a state in which a side cover16covering the valve body12is removed.FIG. 1Cshows the side cover16.FIG. 1Dshows a cross section taken along B-B ofFIG. 1B.

DescribingFIGS. 1A and 1B, the valve body12has a substantially rectangular parallelepiped shape and is disposed adjacently to the side cover16covering the valve body12on the vehicle front side in a vehicle-mounted state i.e., in a state where the valve body12is mounted on a vehicle. The valve body is disposed such that a longitudinal direction (longest part) of the valve body12is parallel with the vertical direction. In other words, the valve body12is disposed in a vertically placed state.

The valve body12is fastened by a plurality of (in this example, eleven) bolts18such that a mating surface of a stepped portion formed on both ends in the vertical direction and both ends in the vehicle width direction comes into contact with a mating surface of a stepped portion formed on the transmission case14.

The valve body12includes a plurality of (in this example, four) electromagnetic valves20on the vehicle front side, i.e., the side adjacent to the side cover. The electromagnetic valves20each have a substantially columnar shape and are disposed such that a longitudinal direction of each the electromagnetic valve20is horizontal to the ground surface. Therefore, the electromagnetic valves20are disposed laterally to the vertically-placed valve body12. Since the electromagnetic valves20are horizontally disposed (laterally placed) relative to the ground surface, a gravity effect, i.e., a valve malfunction due to gravity is suppressed. The electromagnetic valves20are arranged side by side in the vertical direction. The electromagnetic valves20are each connected at one end in the longitudinal direction to a projected portion22projected from the valve body12toward the side cover16.

As shown inFIG. 1C, the side cover16has a bottomed tray shape and is fastened by a plurality of bolts24such that a mating surface16aformed on the outer edge of the side cover16comes into contact with a mating surface14aformed on the transmission case14.

The electromagnetic valves20are laterally placed and arranged side by side in the vertical direction with both ends in the longitudinal direction aligned when viewed in the vertical direction. As a result, spaces26,28indicated by broken lines ofFIG. 1Bare formed between both ends of the electromagnetic valves20and the outer edge of the side cover16. Both the spaces26,28have a shape elongated in the vertical direction. In this example, a strainer for removing a foreign material is disposed in the space26. Specifically, when viewed in the direction parallel and horizontal to the mating surfaces14a,16aof the transmission case14and the side cover16(i.e., the direction of viewing along a plane including a point C ofFIG. 1Dand parallel to the mating surfaces14a,16a), the strainer is disposed to overlap with at least a portion of the electromagnetic valves20as indicated by a dashed-dotted line. In other words, the strainer is disposed at a position without overlap with the electromagnetic valves20when viewed in the perpendicular direction. It is noted that the spaces26,28are formed between the end portions of the electromagnetic valves20and the outer edge of the side cover16because spaces are necessary for disposing the bolts18connecting the valve body12to the transmission case14.

FIGS. 2A and 2Bshow a form in which a strainer30ais disposed in the space26formed between the valve body12and the side cover16.FIG. 2Acorresponds toFIG. 1A, andFIG. 2Bshows a hydraulic circuit, which corresponds toFIG. 2A. InFIG. 2A, the strainer30ais disposed at a position corresponding to the space26ofFIG. 1B. As can be seen fromFIG. 2A, when viewed in the direction parallel and horizontal to the mating surfaces14a,16aof the transmission case14and the side cover16(the direction of viewing along a plane including a point D ofFIG. 2Aand parallel to the mating surfaces14a,16a), the strainer30ais disposed to overlap with at least a portion of the electromagnetic valves20as indicated by a dashed-dotted line.

The side cover16and the strainer30aare each made up of a resin member. The strainer30ahas a tray shape formed longitudinally in the vertical direction and the opening side thereof is integrally connected to the side cover16by bolts not shown, for example. A first space31is formed between the side cover16and the strainer30a.

At a position higher than an oil surface (oil level) in the vertical direction of the strainer30a, an inflow portion32is disposed for allowing a hydraulic oil to flow into the first space31from the valve body12as indicated by an arrow.FIG. 2Bschematically shows a portion of the hydraulic circuit applied inFIG. 2A. The hydraulic pressure of the hydraulic oil pumped up by an oil pump33is used as a source pressure to generate a line pressure, which is supplied to a hydraulic actuator etc. not shown included in the transmission10. A portion of the fluid having hydraulic pressure is adjusted to a lower pressure and then supplied to a lubrication oil passage in the valve body12, and the hydraulic oil in the lubrication oil passage is supplied through the valve body12from the inflow portion32of the strainer30a.

At a position lower than the oil surface (oil level) in the vertical direction of the strainer30a, an outflow portion34is disposed for allowing the hydraulic oil filtered through a filter36(filter material) to flow out to the valve body12as indicated by an arrow. The hydraulic oil flowing out from the outflow portion34is supplied through the valve body12to lubrication required portions requiring lubrication and is used for lubrication of the portions.

Since the integration of the side cover16and the strainer30aas described above (a strainer-integrated cover) eliminates the need for a clearance between the side cover16and the strainer30a, a larger space can be ensured for disposing the strainer30a. Therefore, since the physical size of the strainer30acan be made larger, the strainer30acan be increased in strength and improved in filtering performance. Additionally, the lower-pressure hydraulic oil flowing from the valve body12is advantageous to the side cover16and the strainer30ain view of strength so that the side cover16and the strainer30acan be made thinner in plate thickness (resin plate thickness).

Since the inflow portion32is disposed at a position higher than the oil surface (oil level) in the vertical direction of the strainer30aand the hydraulic oil flows in via this position, the filtering can be performed by using gravity and a hydraulic pressure loss (pressure loss) of the hydraulic oil is reduced. As a result, a pumping work of the oil pump can be reduced. Additionally, the filter36is disposed such that the longitudinal dimension thereof is the vertical direction in the first space31and the first space31is divided by the filter36into two spaces elongated in the vertical direction. The hydraulic oil is filtered when passing through the two spaces formed by the filter36and, additionally, since the hydraulic oil flowing into the first space31moves vertically downward due to gravity and foreign materials in the hydraulic oil are removed also during this moving period by the filter36disposed in the vertical direction, the efficiency of the filtering by the filter36is improved.

FIGS. 3A and 3Bshow another form in which a strainer30bis disposed in the space26between the valve body12and the side cover16.FIG. 3Acorresponds toFIG. 1A, andFIG. 3Bshows a hydraulic circuit, which corresponds toFIG. 3A. InFIG. 3A, the strainer30bis disposed at a position corresponding to the space26ofFIG. 1B. As can be seen fromFIG. 3A, when viewed in the direction parallel and horizontal to the mating surfaces14a,16aof the transmission case14and the side cover16(the direction of viewing along a plane including a point E ofFIG. 3Aand parallel to the mating surfaces14a,16a), the strainer30bis disposed to overlap with a portion of the electromagnetic valves20as indicated by a dashed-dotted line.

The strainer30bis also made up of a resin member. The strainer30bhas a tray shape formed longitudinally in the vertical direction and the opening side thereof is integrally connected to the side cover16by bolts not shown, for example. A first space31is formed between the side cover16and the strainer30b.

At a position higher than an oil surface (oil level) in the vertical direction of the strainer30b, an inflow portion32is disposed for allowing a hydraulic oil to flow into the first space31from the valve body12as indicated by an arrow.FIG. 3Bschematically shows a portion of the hydraulic circuit applied inFIG. 3A. The hydraulic pressure of the hydraulic oil pumped up by an oil pump33is used as a source pressure to generate a line pressure, which is supplied to a hydraulic actuator etc. included in the transmission10. A portion of the hydraulic pressure is adjusted to a lower pressure and then supplied to the inflow portion32of the strainer30bthrough a bypass oil passage branched from the lubrication oil passage in the valve body12.

At positions lower than the inflow portion32in the vertical direction of the strainer30b, at least one oil outflow hole38is formed. Therefore, the hydraulic oil flowing in from the inflow portion32is filtered through the filter36and then drained from the oil outflow hole38as indicated by arrows and, as shown inFIG. 3A, the hydraulic oil flowing out from the oil outflow hole38are accumulated in a second space formed on the transmission case14side.

Since the integration of the side cover16and the strainer30bas described above eliminates the need for a clearance between the side cover16and the strainer30b, a larger space can be ensured for disposing the strainer30b. Therefore, since the physical size of the strainer30bcan be made larger, the strainer30bcan be increased in strength and improved in filtering performance. Additionally, since the hydraulic oil flowing through the bypass oil passage branched from a lubrication oil passage flows to the strainer30b, the hydraulic oil with a lower pressure can be allowed to flow as compared to the hydraulic oil flowing through the lubrication oil passage ofFIGS. 2A and 2Bdescribed above. This is more advantageous to the side cover16and the strainer30bin view of strength so that the side cover16and the strainer30bcan further be made thinner in plate thickness (resin plate thickness).

Since the inflow portion32is disposed at a position higher than the oil surface (oil level) in the vertical direction of the strainer30band the hydraulic oil is supplied from this position, the filtering can be performed by using gravity and a hydraulic pressure loss (pressure loss) of the hydraulic oil is reduced. Since the hydraulic oil is allowed to flow out from the entire side surface of the strainer30b, a reduction in residual pressure inside the strainer (the first space31) enables effective filtering and is also advantageous in view of strength.

As described above, according to this example, since the space26is utilized that is formed by disposing the electromagnetic valves20on the side cover16side of the valve body12between the side cover16and the valve body12and the strainer30a,30bis disposed in the space26at a position without interference of the electromagnetic valves20, the strainer30a,30bcan be disposed without expanding the side cover16. Since the inflow portion32for the hydraulic oil is disposed vertically above the oil surface of the strainer30a,30b, the filtering can be performed by using gravity and the hydraulic pressure loss (pressure loss) of the hydraulic oil can be reduced.

The example of the present invention has been described in detail with reference to the drawings, the present invention can be applied in other forms.

For example, although the valve body is disposed on the front side of the vehicle in the example, the present invention is applicable to vehicle transmission having the valve body disposed on the vehicle rear side or the vehicle lateral side i.e., at one end in the vehicle width direction.

Although the strainer30a,30bis disposed in the space26in the example, the strainer30a,30bmay be disposed in the space28. Although the two spaces of the space26and the space28are formed in the example, the present invention is applicable even when either one of the spaces is formed.

Although both the side cover16and the strainer30a,30bare made up of resin members in the example, this is not necessarily a limitation of the present invention.

Although the strainer30a,30bis formed to the vicinities of the upper and lower outer edges of the side cover16in the vertical direction in the example, this is not necessarily a limitation and the strainer30a,30bmay be formed in a part of the side cover16in the vertical direction.

The above description is merely an embodiment and the present invention may be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

REFERENCE SIGNS LIST