JPH0618042Y2 - Engine chain case structure - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chain case structure of an engine, and more particularly to an improvement of a chain case provided with an oil pump.

(Prior Art) Conventionally, in an engine, for example, JP-A-57-13
As disclosed in Japanese Patent No. 1808, a chain case accommodating a timing chain is detachably attached to an outer surface of an engine body, and an oil pump driven by a crankshaft is provided below the chain case. Things are known. It should be noted that the cover is made of one member as in the above-mentioned official gazette and is made of an inner member and an outer member for covering the chain from the outside, that is, the side opposite to the engine body, and storing the chain. There is a member that stores the chain so that it is sandwiched from both sides.

Further, in order to lubricate the chain housed in the chain case, an oil jet communicating with an oil supply passage formed on the engine body side is provided in a protruding manner in the chain case, or an oil supply passage is provided in the chain case. The constituent pipes are arranged and an oil jet is connected to the pipe, and the oil is sprayed from the oil jet to the chain (Japanese Patent Laid-Open No. 57-5509).
No.

(Problems to be solved by the invention) By the way, the wall thickness of the above-mentioned chain case and the oil pump housing formed in the chain case is usually
It is relatively thin in order to reduce the weight of the entire engine. However, in this case, there is a problem in that the chain case vibrates due to the operation of the oil pump, and abnormal noise or contact wear with the pump rotor easily occurs.

The present invention has been made in view of the above point, and the object thereof is to effectively increase the rigidity of the chain case while reducing the weight of the engine by utilizing the structure for lubricating the chain. This prevents the generation of abnormal noise and wear due to the vibration of the chain case.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the solution means of the present invention is such that a pulley is attached to an end of a crankshaft extending outwardly from the inside of a cylinder block and is wound around the pulley. An engine in which a chain case that covers the chain is arranged on the outer surface of the cylinder block has the following configuration.

That is, an oil pump housing that houses an oil pump driven by a crankshaft is formed in the chain case, and an intake passage and a discharge passage that communicate with the suction port and the discharge port of the oil pump are formed. The discharge port of the oil pump is provided on the upper side of the oil pump housing. An oil boss having a chain lubrication oil supply passage extending laterally from the side seal surface of the chain case to the upper end of the oil pump housing is formed in the chain case, and the oil boss is connected to the oil supply passage. The structure is such that a jetting hole that opens toward the communication chain side is provided.

(Operation) With the above configuration, according to the present invention, the chain case in which the oil pump housing is formed is formed with the oil boss extending laterally from the side seal surface thereof to the upper end of the oil pump housing. The rigidity of the chain case, especially the rigidity of the portion where the oil pump housing is formed, is increased, and vibrations due to the operation of the oil pump are suppressed. In particular, the oil boss
Since it is provided at the upper end of the oil pump housing near the discharge port of the oil pump, it is possible to effectively suppress the vibration caused by the pump pulsation that occurs near the discharge port.

Moreover, the weight reduction of the engine is not impaired by forming the oil boss on the chain case. That is, the oil boss is for forming an oil supply passage for chain lubrication, and the weight of the oil boss is smaller than that in the case where the oil supply passage is formed by a pipe arranged in the chain case as in the conventional case. It only adds to the weight of the pipe and does not add to the overall weight of the engine. Further, compared with the conventional one in which the chain lubrication oil supply passage is formed on the engine body side, in the conventional case, it is necessary to increase the wall thickness of the engine main body in order to form the oil supply passage. , In the case of the present invention in which it is not necessary to increase this wall thickness,
Looking at the engine as a whole, including the chain case, it is possible to reduce its weight.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an engine having a chain case structure according to an embodiment of the present invention, 1 is a cylinder block, 2 is an oil pan attached to the lower portion of the cylinder block 1, and 3 is a cylinder block 1. A crankshaft disposed in the cylinder block 1 of the crankshaft 3
A pulley 4 is attached to an end portion extending forward, and a chain 5 is wound around the pulley 4.

A chain case 12 that covers the chain 5 is arranged on the front outer surface of the cylinder block 1.
The chain case 12 is located on the cylinder block 1 side of the pulley 4 and has an inner member 13 detachably attached to the cylinder block 1 and a rear portion (facing the inner member 13).
An outer member 14 which is formed in a bag-like shape open to the inner member 13 and is detachably attached to the inner member 13 and is attached in an oil sheet state, and the chain 5 between the inner member 13 and the outer member 14 is formed. It is designed to be stored.

An oil pump housing 20 is formed below the inner member 13 of the chain case 12 so as to correspond to the crankshaft 3, and the crankshaft 3 is provided in the housing 20.
The oil pump 21 driven by is accommodated.
The oil pump 21 is an internal gear type having an external tooth drive gear 22 and an internal tooth driven gear 23 as a pump rotor, and the external tooth drive gear 22 is fitted and fixed to the crankshaft 3, and The internal gear driven gear 23 is rotatably fitted in the housing 20.

The structures of the inner member 13 of the chain case 12 and the oil pump housing 20 formed on the inner member 13 are shown in detail in FIGS. 3 to 16. FIG. 3 is a front view of the inner member 13 as viewed from the front (outer member 14 side), and FIG. 4 is a rear view of the inner member 13 as viewed from the rear (cylinder block 1 side). Also, FIGS. 5 and 6
Figure 7, Figure 8, Figure 8 and Figure 9 are B of Figure 3, respectively.
FIG. 10 is a view taken in the directions of arrows C, D, E, and F, and FIGS. 10 and 16 are G- of FIG. 3, respectively.
It is sectional drawing in the G line and the MM line. FIG. 11,
12, FIG. 13, FIG. 14 and FIG. 15 are cross-sectional views taken along the lines HH, I-I, JJ, KK and LL of FIG. 4, respectively. .

In FIG. 3 to FIG. 10, a joining surface 24 for joining and connecting with the outer member 14 is provided on the front surface side of the inner member 13.
And a plurality of bolt bosses 25, 25, ...
And a flange portion 26 projecting forward from the joint surface 24 is formed at the lower end of the inner member 13, and the flange portion 26 has an upper end at the front edge of the oil pan 2 as shown in FIG. Are fixed by bolts 27. Further, on the rear surface side of the inner member 13, a joining surface 2 for joining and connecting to the cylinder block 1 is formed.
8 and a plurality of bolt bosses 29, 29 having a screw hole or a bolt insertion hole are formed, and an oil pump housing 20 is formed around the lower crankshaft penetrating portion 30.

The oil pump housing 20 has an outer peripheral wall portion 20.
A peripheral portion of the oil pump cover 31 is attached to a by bolts 32 to form a space (pump chamber) for housing the oil pump 21. A suction port 34 is opened in a lower portion of the housing 20 on the suction chamber 33 (right half portion of the pump chamber in FIG. 4) side.
11 communicates with the suction passage 35 formed in the inner member 13 and the introduction pipe 36 (see FIG. 1) connected to the suction passage 35 as shown in FIG. 11, and collects at the bottom of the oil pan 2. The oil is sucked into the suction chamber 33 of the housing 20 through the introduction pipe 36 and the suction passage 35. On the other hand, the discharge chamber 37 of the housing 20 (fourth
A discharge port 38 is opened in the upper part on the left half side of the pump chamber in the figure, and the discharge port 38 is formed in the inner member 13 as shown in FIGS. 12 and 13. 39
The oil which is communicated with a and 39b and whose pressure is increased by the operation of the oil pump 21 in the housing 20 is discharged from the discharge port 3
8 through the discharge passages 39a, 39b from the inner member 13
It is designed to be discharged outside.

The upper part of the oil pump housing 20 rotatably guides the internal gear driven gear 23 of the oil pump 21 by the outer peripheral wall part 20a, while the lower part is provided inside the outer peripheral wall part 20a at a predetermined distance. The inner tooth driven gear 23 is rotatably guided by the guide wall 40, and a recirculation passage 41 extending along the guide wall 40 is provided between the guide wall 40 and the outer peripheral wall portion 20a. Are formed. One end of the recirculation passage 41 communicates with the vicinity of the suction port 34 of the suction chamber 33, while the other end of the recirculation passage 41 has a communication hole 43 in a valve housing 42 formed in the inner member 13.
Are communicated via. The valve housing 42
As shown in FIG. 14 and FIG. 15, is connected to the discharge port 38, and a relief valve 44 is provided inside thereof. The relief valve 44
Is a valve body 45 slidably fitted in the valve housing 42, an adjusting screw 46 screwed into an opening of the valve housing 42, and a compression member between the valve body 45 and the adjusting screw 46. And a spring 47 that is opened. Then, when the pressure of the oil discharged from the discharge port 38 exceeds a predetermined value, the relief valve 44 is opened and the discharged oil is returned from the discharge port 38 side to the suction chamber 33 side via the recirculation passage 41. It is supposed to be.

As a feature of the present invention, the inner member 13 is provided with an oil boss 49 having an oil supply passage 48 for chain lubrication, as shown in FIG.
It is formed so as to extend in the horizontal direction (lateral direction) across the upper ends of the oil pump housing 20 from the side edge joint surfaces (side seal surfaces) 24, 28, and the front side surface of the oil boss 49 (side surface on the outer member 14 side). ) In the oil supply passage 48
Is provided with two oil jet connection holes 50a and 50b, which communicate with each other and open toward the chain 5 side. An oil jet 51 is connected to each of the connection holes 50a and 50b as shown in FIGS. 17 and 18, and oil is sprayed from the oil jet 51 onto the chain 5 to lubricate the chain 5. There is. The oil supply passage 48 communicates with an oil supply passage 52 formed in the cylinder block 1 as shown in FIG. 1, and oil is passed through the oil supply passages 48 and 52 to the crank bearing portion of the cylinder block 1. Etc.

Therefore, in the above-described embodiment, the oil boss 48 that extends laterally from the side seal surfaces 24 and 28 of the chain member 12 of the chain case 12 in which the oil pump housing 20 is formed extends laterally from the side seal surfaces 24 and 28. By being formed, the rigidity of the oil pump housing 20 or the inner member 13 can be effectively increased in a state where the oil pump housing 20 is connected to the side seal surfaces 24, 28 having high rigidity of the inner member 13. , The oil pump housing 20 and the inner member 13 by the operation of the oil pump 21
It is possible to prevent the generation of abnormal noise and prevent contact wear with the pump rotor (external tooth drive gear 22 and internal tooth driven gear 23). In particular, since the oil boss 48 is provided at the upper end of the oil pump housing 20 near the discharge port 38 of the oil pump 21, the oil boss 48 is effective against vibration caused by pump pulsation near the discharge port 38. Can be suppressed.

Moreover, the oil boss 48 serves to form the chain lubrication oil supply passage 49, and is a side wall of the engine body (cylinder block 1) for forming a conventional oil supply passage or a pipe forming the oil supply passage. Since it is provided instead of setting the wall thickness of the engine to be thick, the weight of the engine can be reduced without increasing the weight of the entire engine.

In the above embodiment, the present invention provides a chain case 12 for accommodating the chain 5 with an inner member 13 and an outer member 14.
The present invention is applied to the case where the oil pump housing 20 is formed in the lower part of the inner member 13, but the chain case covers the chain from the outer side and stores it.
Of course, the same can be applied to the case where the oil pump housing is formed of two members and the lower part thereof is formed.

(Effects of the Invention) As described above, according to the chain case structure of the engine of the present invention, the chain case in which the oil pump housing is formed is laterally extended from the side seal surface of the chain case to the upper end portion of the oil pump housing. By forming an oil boss with an extended chain lubrication oil supply passage, while reducing the weight of the engine,
Since the rigidity of the chain case can be increased, abnormal noise and wear due to its vibration can be effectively prevented, and the chain case is excellent in practicality.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an enlarged sectional view taken along the line AA in FIG. 2, FIG. 2 is a vertical sectional front view of a chain portion of an engine, and FIG. 3 is an inner member. Front view,
FIG. 4 is a rear view of the same, and FIGS. 5, 6, 7, 8, and 9 are B, C, and D of FIG. 3, respectively.
It is the arrow line view seen from the arrow, E arrow, and F arrow direction. Tenth
The drawing is a cross-sectional view taken along the line GG in FIG.
FIG. 12, FIG. 13, FIG. 13, FIG. 14 and FIG. 15 are respectively the HH line, the I-I line, the JJ line and the KK of FIG.
FIG. 16 is a sectional view taken along the line LL, and FIG. 16 is a sectional view taken along the line MM in FIG. 17 and 18
The drawings are cross-sectional views showing the mounting state of the oil jet taken along line NN and line OO in FIG. 3, respectively. 1 ... Cylinder block, 3 ... Crank shaft, 4 ... Pulley,
5 ... Chain, 12 ... Chain case, 13 ... Inner member, 20 ... Oil pump housing, 21 ... Oil pump, 34 ... Suction port, 35 ... Suction passage, 38 ... Discharge port, 3
9a, 39a ... Discharge passage, 48 ... Oil supply passage, 49
... Oil boss, 50a, 50b ... Oil jet connection hole (spout hole).

Claims (1)

[Scope of utility model registration request] 1. An engine in which a pulley is attached to an end portion of a crankshaft extending outward from the inside of a cylinder block, and a chain case covering a chain wound around the pulley is arranged on an outer surface of the cylinder block. An oil pump housing that accommodates an oil pump driven by the crankshaft is formed in the chain case, and an intake passage and a discharge passage that communicate with the suction port and the discharge port of the oil pump are formed. The discharge port of the oil pump is provided on the upper side of the oil pump housing, and the chain case laterally extends from the side seal surface of the chain case to the upper end of the oil pump housing. An oil boss having an oil supply passage for chain lubrication is formed. Rubosu, the chain case structure for an engine, characterized in that the oil supply passage and communicating ejection holes opening toward the chain side.