Valve timing variation device

Abstract: Since the conventionally the chip seal 14, 16 and the metallic blade spring 15, 17 have been formed separately, assembly efficiency has been poor (for example when the chip seal 14, 16 is inserted, the metallic blade spring 15, 17 detaches and falls out) which lowers productivity. As a result, the cross sectional shape of the chip seal 21 which pushes against the rotor 13 is made in the shape of a letter L.

Description: Field of the Invention The present invention relates to a valve timing variation device which controls the timing-of the opening and closing of a valve. Description of the Prior Art Figures 5 and 6 are cross sections showing a conventional valve timing variation device. Figures 7A and 7B are cross sections showing the structure of a chip seal of a valve timing variation device. In the figures, reference numeral 1 denotes an electronic control unit (hereafter ECU) which controls the oil control valve 2 and the like. 2 is an oil control valve (hereafter OCV) which supplies working oil to the actuator 3 under the control of the ECU 1. 3 is an actuator which controls the displacement angle of the camshaft 6 with respect to the timing pulley 8 when the working oil is supplied from the OCV 2 and which continuously regulates the timing of the opening and closing of the air intake valve. 4 and 5 are oil passages through which the working oil which is supplied from the OCV 2 flows. 6 is a camshaft which drives the opening and closing of the intake valve of the engine. 7 is a cam of the camshaft 6. 8 is a timing pulley arranged on one end of the camshaft 6. 9 is a bearing of the camshaft 6. 10 is a housing mounted so as to be freely rotatable with respect to the camshaft 6. 11 is a case fixed to the housing 10. 12 is a bolt which fixes the case 11 to the housing 10. 13 is a rotor which is fixed to the camshaft 6 and which rotates relative to the case 11. 14 and 16 are chip seals which prevent the movement of oil between the oil chambers 18 which are separated by the case 11 and the rotor 13. 15 is a metallic blade spring which is disposed between case 11 and the chip seal 14 and which pressures the chip seal 14 against the rotor 13. 17 is a metallic blade spring which is disposed between rotor 13 and the chip seal 14 and which pressures the chip seal 16 against the case 11. 18 are oil chambers which are separated by the case 11 and the rotor 13. Next the operation of the invention will be explained. Although the valve timing variation device controls the rotational direction of the housing 10 and the timing of the opening and closing of the air intake and exhaust valves of the engine by controlling of the amount of oil flowing into each oil chamber 18, in order to prevent the movement of oil between the oil chambers 18, a chip seal 14 is pushed against the rotor 13 and a chip seal 16 is pushed against the case 11. In other words, as shown in Figure 7A, the chip seal 14 is pushed against the rotor 13 by the blade spring 15 disposed between the case 11 and the chip seal 14. Furthermore the chip seal 16 as shown in Figure 7B, is pushed against the case 11 by the blade spring 17 which is disposed between the rotor 13 and the chip seal 16. The attachment of the chip seals 14 and 16 is performed by insertion between the case 11 and the rotor 13 in the direction from the left side of Figures 7A and 7B (the front of Figure 6) to the right side (the back of Figure 7) so that the chip seals 14, 16 and the metallic blade springs 15; 17 do not become disassembled. Apart from the conventional example given above, a similar arrangement is disclosed in JP-A-9-324611. Since conventional valve timing variation devices are constructed as above, chip seals 14, 16 are pushed onto the rotor 13 or the case 11 using blade springs 15, 17. However since the chip seals 14, 16 and the blade springs 15, 17 have different structures, the problem has arisen that assembly efficiency is extremely poor (for example when the chip seals 14, 16 are inserted the blade spring 15, 17 becomes detached and fall out) which reduces productivity. Summary of the Invention The present invention is proposed to solve the above problems and has the objective of obtaining a valve timing variation device which can increase assemblying efficiency when the chip seals are assembled. The object is solved by the subject matter defined in claims 1 and 2. According to one embodiment of the invention, the chip seal of the valve timing variation device has the shape of a letter "L" when taken in cross section. According to this embodiment of the invention, since the cross sectional shape of the chip seal has the shape of a letter "L", the efficiency of assembling the chip seal can be increased. According to a further embodiment of the present invention, the valve timing-variation device is adapted to fix the flexible member which has lower hardness than the chip-seal to the chip seal. Accordingly, by fixing the flexible member which has lower hardness than the chip seal to the chip seal, it is possible to lower manufacturing costs and to conspicuously increase assembling efficiency of the chip seal. According to still another embodiment of the present invention, the valve timing variation device is adapted so that the flexible member is formed by two legs. According to this embodiment, since the flexible member is formed by two legs it is possible to improve assembling efficiency of the chip seal. According to another embodiment of the invention, the valve timing variation device is adapted to construct the member on the rotor side of the chip seal using soft flexible resin. Accordingly, using soft flexible resin to construct the member on the rotor side of the chip seal enables the flexible member to be dispensed with. According to still another embodiment of the present invention, the valve timing variation device is adapted so that the chip seal is pushed towards the case side by the flexible member. According to this embodiment, since the chip seal is pushed towards the case side by the flexible member, it is possible to prevent the movement of oil between the oil chambers which are separated by the case and the rotor. According to a further embodiment, the valve timing variation device is adapted so that the chip seal is pushed towards the rotor side by the flexible member. Accordingly, since the chip seal is pushed towards the rotor side by the flexible member, it is possible to prevent the movement of oil between the oil chambers which are separated by the case and the rotor. Brief Description of the Drawings Figures 1A and 1B are cross sections which show the structure of a chip seal of a valve timing variation device according to one embodiment of the present invention. Figures 2A and 2B are cross sections which show the structure of a chip seal of a valve timing variation device according to still another embodiment of the present invention. Figures 3A and 3B are cross sections which show the structure of a chip seal of a valve timing variation device according to another embodiment of the present invention. Figures 4A and 4B are cross sections which show the structure of a chip seal of a valve timing variation device according to a further embodiment of the present invention. Figure 5 is a cross section showing a conventional valve timing variation device. Figure 6 is a cross section showing a conventional valve timing variation device. Figures 7A and 7B are cross sections which show the structure of a chip seal of a valve timing variation device. Detailed Description of the Preferred Embodiments below. Embodiment 1 Figures 1A and 1B are cross sections which show the structure of a chip seal of a valve timing variation device according to the first embodiment of the present invention. In the figures, reference numeral 11 denotes a case fixed to a housing 10, 11a is a notch of the case 11 which stores the chip seal 21 and 13 is a rotor which fixed to the camshaft 6 and which rotates relative to the case 11. 13a is a notch of the rotor 13 which stores the chip seal 23. 21 and 23 are chip seals which prevent the movement of oil between the oil chambers 18 which are separated by the case 11 and the rotor 13. 21a and 23a are distal sections of the chip seals 21, 23. 22 is a metallic blade spring (flexible member) which is disposed between the case 11 and the chip seal 21 and which pressures the chip seal 21 against the rotor 13. 24 is a is a metallic blade spring (flexible member) which disposed between the rotor 13 and the chip seal 23 and which pressures the chip seal 23 against the case 11. Next the operation of the invention will be explained. The valve timing variable device controls the axial direction of the housing and the timing of the opening and closing of the exhaust valve and the air intake valve of an engine by controlling the amount of oil entering the oil chambers 18. In order to prevent the movement of oil between each oil chamber 18, a chip seal 21 is pressed against the rotor 13 and a chip seal 23 is pressed against the case 11. In other words, as shown in Figure 1A, the chip seal 21 is pressed against the rotor 13 by the metallic blade spring 22 disposed between the case 11 and the chip seal 21. The chip seal 23 as shown in Figure 1B is pressed against the case 11 by the metallic blade spring 22 disposed between the rotor 13 and the chip seal 23. However the chip seals 21, 23 are different from conventional chip seals 14, 16. Their cross sectional shape is in the shape of a letter L and the sealing performance of the lateral sections of the chip seals 21, 23 is improved as the lateral sections of the chip seals 21, 23 are stored in the notches 11a, 13a of the rotor 13 and the case 11. The assembly of the chip seal 21, 23 is performed by insertion between the case 11 and the rotor 13 from the left side of Figures 1A and 1B (the front of Figure 8) towards the right side (the rear of Figure 8) so that the chip seals 21, 23 and the metallic blade springs 22, 24 do not become disassembled. The insertion of the tip 21a, 23a of the chip seals 21, 23 is easy due to the fact that the tip 21a, 23a of the chip seals 21, 23 is narrow in comparison with conventional chip seals 14, 16. Hence the ease of assembly of the chip seal can be improved. Embodiment 2 The chip seal can be integrated with the flexible member. However as shown in Figures 2A and 2B, a flexible member of lower hardness than the chip seal may be fixed to the chip seal. In other words, as shown in Figure 2A, when the chip seal 31a is pushed against the rotor 13, the chip seal 31 on the rotor side 13 is constructed using a hard highly slidable resin such as nylon or carbon. The chip seal 31b (flexible member) on the case side 11 is constructed using a soft resin with high flexibility such as rubber or elastomer. Furthermore as shown in Figure 3B, when the chip seal 32a is pushed against the case 11, the chip seal 32a on the case side 11 is constructed using a hard highly slidable resin such as nylon or carbon. The chip seal 32b (flexible member) on the rotor side 13 is constructed using a soft resin with high flexibility such as rubber or elastomer. In this way since a flexible member such as the metallic blade spring becomes redundant, costs are reduced and assembling efficiency is conspicuously improved. Embodiment 3 In embodiment 3, as shown in Figures 3A and 3B, leg sections are laminated to the slidable surface of the chip seals 29, 30 and both legs 29a, 29b, 30a, 30b may be constructed using a soft highly flexible resin such as rubber or elastomer. Hence, as a flexible member such as a metallic blade spring becomes redundant, costs are reduced and the assembly efficiency is conspicuously improved. Embodiment 4 In embodiment 2 above, a bilayer of two resins of different hardness was formed to construct the chip seal. However as shown in Figures 4A and 4B, the cross sectional shape of the chip seal may be in the shape of a letter L. In this way, the same effect as embodiment 2 above is achieved and the performance of the seal on the lateral surface of the chip seal is enhanced.

Claims: A valve timing variation device comprising a case (11) which is fixed to a housing (10), a rotor (13) which is fixed to a camshaft (6) and which rotates relative to the case and a chip seal (21, 23, 31a, 32a) which prevents the movement of oil between oil chambers (18), which are separated by the case and the rotor, the chip seal being pushed by a flexible member (22, 24, 31b, 32b) characterized in that the cross sectional shape of the chip seal is in the shape of a letter L, wherein the cross section is taken along a line within a plane containing the camshaft axis. A valve timing variation device comprising a case (11) which is fixed to a housing (10), a rotor (13) which is fixed to a camshaft (6) and which rotates relative to the case and a chip seal (25, 27, 29, 30, 31a, 32a) which prevents the movement of oil between oil chambers (18), which are separated by the case and the rotor, the chip seal being pushed by a flexible member (26, 28, 29a, 29b, 30a, 30b,-31b, 32b) characterized in that the chip seal is integrally formed with the flexible member, wherein the flexible member (29a, 29b, 30a, 30b, 31b, 32b) is of lower hardness than that of the chip seal(29, 30, 31a, 32a) and fixed to the chip seal. A valve timing variation device according to claim 2,wherein the flexible member (29a, 29b, 30a, 30b, 31b, 32b) of lower hardness than that of the chip seal(29, 30, 31a, 32a) is fixed to the chip seal, characterized in that the flexible member is formed by two legs. A valve timing variation device according to any one of the preceding claims characterized in that said chip seal (23, 27, 30, 32a) is pushed on the case side (11) by a flexible member (24, 28, 30a, 30b, 32b). A valve timing variation device according to any one of the preceding claims characterized in that the chip seal (21, 25, 29, 31a) is pushed on the rotor side (13) by a flexible member (22, 26, 29a, 29b, 31b).

Inventors: FUKUHARA KATUYUKI, SEKIYA MUTSUO, YAMAUCHI MAKOTO, FUKUHARA, KATUYUKI, SEKIYA, MUTSUO, YAMAUCHI, MAKOTO, Fukuhara, Katuyuki, c/oMitsubishi Electric Control
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1999
Main classification: F01L1
IPC codes: F02F11, F01L1